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Sample records for helical ct comparison

  1. Fundamental efficiency of new-style limited-cone-beam CT (3DX). Comparison with helical CT

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    Honda, Kazuya; Arai, Yoshinori; Iwai, Kazuo; Hashimoto, Koji; Shinoda, Koji [Nihon Univ., Tokyo (Japan). School of Dentistry; Saitou, Tsutomu

    2000-12-01

    Limited-cone-beam CT named 'Ortho-CT' has been used clinically for more than 2 years. On the basis of this experience we developed the new-style limited-cone-beam CT for practical use named '3DX Multi image micro CT' (3DX). Purpose of this study was to evaluate the fundamental efficiency of this new-style limited-cone-beam CT in comparison with helical-CT. The resolutions of 3DX was evaluated with MTF (Modulation transfer function). 3DX were compared with helical CT about the fundamental efficiency. The subjective image quality was evaluated with the anatomical landmarks which included inner ear, temporomandibular joint (TMJ), and the maxillary first molar and mandibular first molar. Five dental radiologists and two otolaryngologists evaluated the quality of 3DX image in comparison with that of helical CT images on the same observation point. The five-point scale used ranged from point one (inferior) to five (superior). The skin doses of 3DX and helical CT were measured using TLD on the Rando phantom. The resolution of 3DX was 3.1 line pair/mm (horizontal) and 4.2 line pair/mm (vertical). The subjective image quality of 3DX was better than that of helical CT at every observational point. The minimum score was 3.46 and maximum score was 4.03. There was a significant difference in every observation point (p<0.05). The skin doses were 1.19 mSv with 3DX and 160.0 mSv with helical CT. The skin dose of 3DX was very low compared with that of helical CT. The image showed very high resolution in comparison with that of helical CT. The skin dose was under the one-percent as against helical CT. This system is very useful for diagnosis of tooth and bone in dental and otological field. (author)

  2. Helical CT for lumbosacral spinal

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    Tatsuno, Satoshi; Fukuda, Kunihiko [Jikei Univ., Tokyo (Japan). School of Medicine

    1996-10-01

    The aim of this study was to investigate the efficacy of helical CT for lumbosacral pathology. We performed helical CT with multiplanar reconstruction, including the formation of oblique transaxial and coronal images, in 62 patients with various lumboscral disorders, including 32 non-enhanced CT and 36 CT after myelography. We correlated the appearance of the stenotic spinal canal and neoplastic disease with the findings on MRI obtained at nearly the same time. We obtained helical CT images in all cases in about 30 seconds. The diagnostic ability of helical CT was roughly equal to that of MRI in patients with spondylosis deformans, spondylolisthesis and herniated nucleus pulposus. There was no significant difference in diagnostic value for degenerative lumbosacral disease with canal and foraminal stenosis between non-enhanced and post-myelography helical CT. However, non-enhanced helical CT could not clearly demonstrate neoplastic disease because of the poor contrast resolution. Helical CT was useful in evaluating degenerative disorder and its diagnostic value was nearly equal to that of MRI. We considered that helical CT may be suitable for the assessment of patients with severe lumbago owing to the markedly shortened examination time. However, if helical CT is used as a screening method for lumbosacral disease, one must be careful of its limitations, for example, poor detectability of neoplastic disease, vascular anomalies and so on. (author)

  3. Imaging skeletal anatomy of injured cervical spine specimens: comparison of single-slice vs multi-slice helical CT

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    Obenauer, S.; Alamo, L.; Herold, T.; Funke, M.; Kopka, L.; Grabbe, E. [Department of Radiology, Georg August-University Goettingen, Robert-Koch-Strasse 40, 37075 Goettingen (Germany)

    2002-08-01

    Our objective was to compare a single-slice CT (SS-CT) scanner with a multi-slice CT (MS-CT) scanner in the depiction of osseous anatomic structures and fractures of the upper cervical spine. Two cervical spine specimens with artificial trauma were scanned with a SS-CT scanner (HighSpeed, CT/i, GE, Milwaukee, Wis.) by using various collimations (1, 3, 5 mm) and pitch factors (1, 1.5, 2, 3) and a four-slice helical CT scanner (LightSpeed, QX/i, GE, Milwaukee, Wis.) by using various table speeds ranging from 3.75 to 15 mm/rotation for a pitch of 0.75 and from 7.5 to 30 mm/rotation for a pitch of 1.5. Images were reconstructed with an interval of 1 mm. Sagittal and coronal multiplanar reconstructions of the primary and reconstructed data set were performed. For MS-CT a tube current resulting in equivalent image noise as with SS-CT was used. All images were judged by two observers using a 4-point scale. The best image quality for SS-CT was achieved with the smallest slice thickness (1 mm) and a pitch smaller than 2 resulting in a table speed of up to 2 mm per gantry rotation (4 points). A reduction of the slice thickness rather than of the table speed proved to be beneficial at MS-CT. Therefore, the optimal scan protocol in MS-CT included a slice thickness of 1.25 mm with a table speed of 7.5 mm/360 using a pitch of 1.5 (4 points), resulting in a faster scan time than when a pitch of 0.75 (4 points) was used. This study indicates that MS-CT could provide equivalent image quality at approximately four times the volume coverage speed of SS-CT. (orig.)

  4. Diagnosis of acute pulmonary embolism: Comparison between helical CT and DSA in the animal experiment; Diagnostik der akuten Lungenembolie: Vergleich zwischen Spiral-CT und DSA im Tierexperiment

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    Schmitz-Rode, T. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik; Kilbinger, M. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik; Adam, G. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik; Guenther, R.W. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik

    1995-10-01

    In 11 dogs, lobar, segmental, and subsegmental occlusions of the pulmonary arteries were produced. Subsequent to selective pulmonary angiography, the animals were examined with contrast-enhanced helical CT. In the main and lobar pulmonary arteries there was a complete correlation between CT and DSA in documentation of total and partial embolic occlusions. Identification of segmental and subsegmental pulmonary emboli by CT required a second run with optimized parameters in 7 of 11 cases. Nevertheless, 18% of the peripheral arteries could not be classified. (orig./MG) [Deutsch] In 11 Hunden wurden embolische Verschluesse lobaerer, segmentaler und subsegmentaler Pulmonalarterien erzeugt. Im Anschluss an die selektive Pulmonalisangiographie wurden die Tiere computertomographisch im Bolus-Spiral-Modus untersucht. Im Bereich der Pulmonalishauptstaemme und der Lobararterien ergab sich eine vollstaendige Uebereinstimmung von CT und DSA in der Darstellung kompletter und partieller embolischer Verschluesse. Der CT-Nachweis von Embolien auf Segment- und Subsegmentebene machte in 7 von 11 Faellen einen zweiten Untersuchungsgang mit optimierten Parametern erforderlich. Dennoch waren 18% der peripheren Arterien nicht sicher beurteilbar. (orig./MG)

  5. Helical CT findings in mesenteric ischemia

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    Kim, Seung Hoon; Lim, Hyo Keun; Lee, Won Jae; Choi, Sang Hee; Lee, Soon Jin; Cho, Jae Min; Kim, Kyung Ah; Lee, Yon Ok [Sungkyunkwan Univ. College of Medicine. Samsung Medical Center, Seoul (Korea, Republic of)

    1998-08-01

    Ischemic bowel disease is one of the common causes of acute abdomen, which results from insufficient blood flow to the small bowel and colon caused by arterial or venous occlusion or mesenteric vasoconstriction. Early diagnosis by clinical, laboratory, and radiologic findings is often difficult and delay in adequate therapy results in substantial morbidity and mortality. CT is known to be useful for the evaluation of patients with suspected bowel ischemia or infarction. This study describes the spectrum of helical CT findings in acute and chronic mesenteric ischemia due to various causes, and explains the value of CT findings for specific diagnosis.

  6. Helical CT of the urinary organs

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    Schreyer, H.H.; Uggowitzer, M.M.; Ruppert-Kohlmayr, A. [Graz Univ. (Austria). Dept. of Radiology

    2002-03-01

    Despite of the diagnostic potential of conventional CT (CCT), limitations being inherent in this technology reduce its diagnostic confidence and limit clinical CT applications as 3D imaging. Helical CT (HCT) has far overcome the limitations of CCT and has become the standard CT technology. After a short overview on the technique of HCT and its advantages over CCT, the impact of HCT on the detection of disorders of the urinary organs is discussed. Due to the high quality of 3D reconstructions, vessels are visualized free of artefacts resulting in a dramatic improvement and acceptance of CT angiography, which has become a clinically important examination in the evaluation of obstructive renal artery disease. Fast HCT provides a precise assessment of the three phases of the nephrogram and it is a prerequisite for an improved depiction of abnormal vascular perfusion and impaired tubule transit of contrast material. Helical CT enables an improved characterization of cystic mass lesions reducing the diagnosis of indeterminate masses and thus facilitating a better therapeutic management. The diagnosis of renal cell carcinomas (RCC) has improved due to an increased sensitivity in detecting small RCCs, and an increased specificity in the diagnosis of neoplastic lesions. Improved staging of RCCs is the result of accurate assessment of venous tumour extension. When planning nephron-sparing surgery 3D display of the renal tumour helps to determine the resectability of the mass depicting its relation to major renal vessels and the renal collecting system. In the evaluation of renal trauma HCT provides shorter scanning time and thus fewer artefacts in the examination of traumatized patients who cannot cooperate adequately. Three-dimensional postprocessing modalities allow the assessment of the renal vascular pedicel by CT angiography and improve the demonstration of complex lacerations of the renal parenchyma. In the evaluation of the upper urinary tract unenhanced HCT has

  7. Unenhanced helical CT in the evaluation of the urinary tract in children and young adults following urinary tract reconstruction: comparison with sonography

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    Myers, M.T.; Elder, J.S.; Sivit, C.J.; Applegate, K.E. [Dept. of Radiology, Rainbow Babies and Children' s Hospital, Cleveland, OH (United States)

    2001-03-01

    Purpose. To compare the accuracy of unenhanced, helical CT with sonography for the detection of complications of urinary tract reconstruction. Materials and methods. Forty-six kidneys in 24 patients were examined with CT and sonography. All scans were assessed for ease of renal visualization, presence of renal, ureteral, and bladder calculi, renal scars, hydronephrosis, and abdominal wall hernia. The results of both imaging modalities were independently reported. Results. CT provided excellent visualization of all 46 kidneys, while sonography provided poor visualization of 8 kidneys (17 %) (P < 0.001). CT detected calculi in 10 kidneys, 1 ureter, and 7 bladders. Sonography detected calculi in only 2 kidneys, and 2 bladders. Overall, CT detected significantly more calculi than US (18 vs 4, P = 0.01). CT detected scarring in 15 kidneys, while sonography detected scarring in 10. Hydronephrosis was detected in 6 kidneys by CT and in 8 kidneys by sonography. Three abdominal wall hernias were seen at CT that were not seen at sonography. Conclusion. CT is superior to sonography for the detection of urinary tract calculi and renal scarring. CT will demonstrate abdominal wall hernias that are unsuspected. (orig.)

  8. Helical CT defecography; La defecografia con Tomografia Computerizzata spirale

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    Ferrando, R.; Fiorini, G.; Beghello, A.; Cicio, G.R.; Derchi, L.E.; Consigliere, M.; Resasco, M. [Genua Univ., Genua (Italy). Ist. di Radiologia, Cattedra R; Tornago, S. [Genua Univ. Genua (Italy). 2 Clinica Ortopedica

    1999-11-01

    The purpose of this work is to investigate the possible role of Helical CT defecography in pelvic floor disorders by comparing the results of the investigations with those of conventional defecography. The series analyzed consisted of 90 patients, namely 62 women and 28 men, ranging in age 24-82 years. They were all submitted to conventional defecography, and 18 questionable cases were also studied with Helical CT defecography. The conventional examination was performed during the 4 standard phases of resting, squeezing, Valsalva and straining; it is used a remote-control unit. The parameters for Helical CT defecography were: 5 mm beam collimation, pitch 2, 120 KV, 250 m As and 18-20 degrees gantry inclination to acquire coronal images of the pelvic floor. The rectal ampulla was distended with a bolus of 300 mL nonionic iodinated contrast agent (dilution: 3g/cc). The patient wore a napkin and was seated on the table, except for those who could not hold the position and were thus examined supine. Twenty-second helical scans were performed at rest and during evacuation; multiplanar reconstructions were obtained especially on the sagittal plane for comparison with conventional defecographic images. Coronal Helical CT defecography images permitted to map the perineal floor muscles, while sagittal reconstructions provided information on the ampulla and the levator ani. To conclude, Helical CT defecography performed well in study of pelvic floor disorders and can follow conventional defecography especially in questionable cases. [Italian] Scopo di questo lavoro e' ricercare un ruolo per la defeco-TC con apparecchiatura elicoidale nello studio delle malattie del pavimento pelvico confrontandola con i risultati consolidati della defecografia tradizionale. Si sono visionati 90 pazienti, 62 femmine e 28 maschi, con eta' compresa tra 24 e 82 anni, con defecografia tradizionale; di questi, 18 casi con diagnosi dubbia sono stati studiati anche con defeco-TC spirale

  9. Diagnosis of lung embolism by V / Q scintigraphy. Pt. 3. Comparison with multislice-helical CT; V / Q-Szintigrafie zur Diagnostik der Lungenembolie. T. 3. Vergleich mit der Mehrzeilen-Spiral-CT

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    Schuemichen, C. [Rostock Univ. (Germany). Klinik und Poliklinik fuer Nuklearmedizin

    2008-12-15

    V / Q scintigraphy can be seen to be equal in many areas to the more modern multislice-helical CT in detecting acute pulmonary embolism and even to be superior with respect to sensitivity. Multislice-helical CT recognizes central emboli with high sensitivity and specificity, but deficits still remain in detecting peripheral embolisms, despite methodical improvements (increase up to 64 slices). Especially measured on the outcome, the overall sensitivity is still too low (ca. 75 %), the reason for this lies less in the image quality than in the evaluation. V / Q scintigraphy has deficits in detecting central emboli which either have no hemodynamic effects or are only partially occluding. Measured on the outsome, the overall sensitivity is still excellent, the number of symptomatic and fatal late embolisms in scintigraphically normal, untreated patients tends toward zero. Decisive for the prognosis are thus embolisms with hemodynamic effects in primary diagnostics. Unlike V / Q scintigraphy, multislice-helical CT also recognizes extrapulmonary diseases as alternative diagnoses, among these aortic dissection. The risk of tumor induction following radiation exposure is higher with multislice-helical CT than with V / Q scintigraphy by more than one order of magnitude. (orig.)

  10. Helical CT of calcaneal fractures: technique and imaging features

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    Wechsler, R.J.; Schweitzer, M.E.; Karasick, D.; Deely, D.M.; Morrison, W. [Thomas Jefferson University Hospital, Department of Radiology, 111 South 11th Street, Philadelphia, PA 19107 (United States)

    1998-01-01

    Since the degree of comminution, fracture alignment, and articular congruity of intra-articular calcaneal fractures are important determinants in surgical treatment and patient prognosis, we review helical computed tomographic (CT) technique and features for detecting and assessing the extent of acute calcaneal fractures. Helical CT can be used to classify these fractures and facilitate the surgeon`s understanding of the anatomy and position of the fracture components in all orthogonal planes independently of the patient`s condition, foot placement in the CT gantry, or other injuries. (orig.) With 13 figs., 13 refs.

  11. Comparison of Helical tomotherapy and Cyberknife in Spine Radiosurgery

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    Kang, Young Nam; Yoon, Se Chul; Chi, Byung Ok; Jng, Hong Suk; Sohn, Suk Hyun [Seoul ST.Mary' s Hospital, The Catholic University of Korea, Seoul (Korea, Republic of); Jung, Gee Young; Shin, Heon Ju; Choi, Ilbong; Gea, Cheol Seong [Incheon ST.Mary' s Hospital, The Catholic University of Korea, Seoul (Korea, Republic of); Kim, Hee Jong [Dept. of Radiation Oncology, Yonsei University, Seoul (Korea, Republic of)

    2011-04-15

    The purpose of this study is planning comparison of helicaltomotherapy and Cyber knife in spine radiosurgery. Spine radiosurgery is an alternative to invasive spine surgery. The tomotherapy is megavoltage CT(MVCT) based image guided helical IMRT delivery system. The cyberknife using robotic arm and image guided based fiducial marker killo voltage X-ray image. The helical tomotherapy is modulated by a 64-multileaf collimator that has paired, pneumatically driven, 6.25-mm-wide leaves calculated to open or close at approximately every 7 .deg. of LINAC rotation, or 51 times per gantry rotation. But cyber knife use 100 or more than bean path. Although, cord maximum dose in CKP is lower than HTP, target homogeneity in HTP is better than CKP. Target coverage is 85% in CKP, 92% in HTP. It was benefit of helical radiation therapy. Tomotheapy and cyberknife are useful equipment to spine radiosurgery.

  12. A rigid motion correction method for helical computed tomography (CT)

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    Kim, J.-H.; Nuyts, J.; Kyme, A.; Kuncic, Z.; Fulton, R.

    2015-03-01

    We propose a method to compensate for six degree-of-freedom rigid motion in helical CT of the head. The method is demonstrated in simulations and in helical scans performed on a 16-slice CT scanner. Scans of a Hoffman brain phantom were acquired while an optical motion tracking system recorded the motion of the bed and the phantom. Motion correction was performed by restoring projection consistency using data from the motion tracking system, and reconstructing with an iterative fully 3D algorithm. Motion correction accuracy was evaluated by comparing reconstructed images with a stationary reference scan. We also investigated the effects on accuracy of tracker sampling rate, measurement jitter, interpolation of tracker measurements, and the synchronization of motion data and CT projections. After optimization of these aspects, motion corrected images corresponded remarkably closely to images of the stationary phantom with correlation and similarity coefficients both above 0.9. We performed a simulation study using volunteer head motion and found similarly that our method is capable of compensating effectively for realistic human head movements. To the best of our knowledge, this is the first practical demonstration of generalized rigid motion correction in helical CT. Its clinical value, which we have yet to explore, may be significant. For example it could reduce the necessity for repeat scans and resource-intensive anesthetic and sedation procedures in patient groups prone to motion, such as young children. It is not only applicable to dedicated CT imaging, but also to hybrid PET/CT and SPECT/CT, where it could also ensure an accurate CT image for lesion localization and attenuation correction of the functional image data.

  13. Hepatic and vascular enhancement at dual-phase helical CT: comparison of Iobitridol 300 and Iohexol 300 in a prospective randomized study

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    Legmann, P.; Vignaux, O.; Bahurel, H.; Oudjit, A. [Dept. of Radiology, Universite Rene Descartes, Paris (France); Coste, J. [Dept. of Biostatistics and Epidemiology, Universite Rene Descartes, Paris (France)

    2001-11-01

    The purpose of this study was to determine hepatic and vascular enhancement, clinical tolerance, and iconographic quality of Iobitridol (300 mg/ml) at dual-phase helical CT and to compare it with Iohexol (300 mg/ml). One hundred forty-six patients were randomly divided into two groups. Each group received 120 ml of Iohexol (group A) or Iobitridol (group B). Mean enhancement of liver, aorta and portal vein was obtained at the arterial phase and at the portal-venous phase. Overall image quality was assessed by two independent blinded investigators. Adverse reactions were recorded. There were no significant differences in demographic characteristics and distribution of patient intrinsic parameters between the two groups, except for blood pressure but without statistical correlation between the difference in blood pressure and the impact on enhancement measurements. There was no significant difference in clinical tolerance and image quality. Mean liver as well as aortic and portal vein enhancement measurements did not show any significant difference. Iobitridol compares favorably with Iohexol. Both products have similar safety, tolerance, and efficacy. Both contrast media have equivalent blood pool concentration and interstitial compartment diffusion. (orig.)

  14. Comparison between helical computed tomography angiography and intraoperative findings

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    Abijit Shetty

    2014-01-01

    Conclusions: Helical CT is important in delineating the arterial, venous, and ureteral anatomy and can show the important incidental findings. Left renal donors and males have more variations in their renal anatomy. Technically challenging laparoscopic nephrectomy on the multiple-vessel-side donor is possible with the aid of helical CT. The importance of the CT in evaluating donor renal anatomy for a technically challenging laparoscopic donor nephrectomy is commendable.

  15. Helical CT in the detection of pulmonary embolism; Spiral-CT in der Diagnostik der Lungenembolie

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    Kauczor, H.U. [Klinik fuer Radiologie, Johannes Gutenberg-Universitaet, Mainz (Germany); Ries, B.G. [Klinik fuer Radiologie, Johannes Gutenberg-Universitaet, Mainz (Germany); Heussel, C.P. [Klinik fuer Radiologie, Johannes Gutenberg-Universitaet, Mainz (Germany); Schmidt, H.C. [Klinik fuer Radiologie, Johannes Gutenberg-Universitaet, Mainz (Germany)

    1996-08-01

    Within a few years, helical CT has proved its value as a useful, relatively risk-free and non-invasive procedure for the detection of acute and chronic pulmonary embolism. Providing the use of carefully chosen angiographic CT procedures of examination, the presence of acute pulmonary embolism may be confirmed or disproved with a high degree of sensitivity and specifity. Even though helical CT is superior to radionuclide procedures as a method of screening for acute pulmonary embolism, acute subsegmental embolism cannot be excluded in all cases, where the examination failed to reveal any particular findings. In the persistence of clinical symptoms and to resolve questions of therapeutical relevance, pulmonary angiography still has an indication. Helical CT must be regarded as the procedure of choice for the detection of chronic pulmonary embolism, while pulmonary angiography is to be used here as a supplementary method in patients undergoing surgery. (orig./VHE) [Deutsch] Die Spiral-CT hat sich innerhalb weniger Jahre als ein aussagekraeftiges, wenig belastendes und nichtinvasives Verfahren in der Diagnostik der akuten und chronischen Lungenembolie bewaehrt. Unter Verwendung gezielter CT-angiographischer Untersuchungsstrategien ist die Diagnose oder der Ausschluss einer akuten Lungenembolie bis zur Segmentebene mit hoher Sensitivitaet und Spezifitaet moeglich. Obwohl die Spiral-CT der Szintigraphie als Screeningverfahren zum Nachweis einer akuten Lungenembolie ueberlegen ist, schliesst eine unauffaellige Spiral-CT jedoch eine akute subsegmentale Lungenembolie nicht sicher aus. Bei fortbestehendem klinischem Verdacht und therapeutischer Konsequenz ist weiterhin die Pulmonalisanigographie indiziert. Fuer die Diagnostik der chronsichen Lungenembolie ist die Spiral-CT als Methode der Wahl anzusehen, die praeoperativ durch die Pulmonalisangiographie ergaenzt werden sollte. (orig./VHE)

  16. Metastatic tumor of the pancreas: helical CT findings

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    Lee, Soon Jin; Lee, Won Jae; Lim, Hyo Keun; Kim, Seung Hoon; Kim, Kyeong Ah; Choi, Sang Hee; Jang, Hyun Jung; Lee, Ji Yeon [Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul (Korea, Republic of)

    2000-04-01

    To analyze the helical computed tomographic (CT) findings of distant metastatic tumors to the pancreas and to determine the differential points between these and primary pamcreatic carcinomas. We sruveyed 22 patients with metastatic tumor of the pancreas, proven on the basis of clinical and pathological findings. Seventeen patients were men, and five were women, and their ages ranged between 36 and 83 years. Their primary conditions were lung cancer (n=3D15), rectal cancer (n=3D2), melanoma of the foot, chondrosarcoma of the sacrum, cervical cancer, leiomyosarcoma of the uterus, and extragonadal choriocarcinoma of the mediastinum. We retrospectively reviewed the abdominal helical CT findings, analysing the number, location, size and attenuation of masses, as well as secondary change, which included dilatation of the pancreatic and biliary ducts and invasion of peripancreatic tissue or vessels. We also evaluated the differential findings of primary pancreatic cancer. Sixteen patients had a solitary focal mass, while in five, two masses were present. Among the 22 patients, low-density nodular masses were present in 21; in the other, in whom multiple metastasis from chondrosarcoma had occurred, there was dense calcification. The size of metastatic masses varied, ranging from 0.6 to 6 cm in diameter. The pancreatic duct proximal to the mass was dilated in ten cases, while the bile duct was dilated in six. The metastatic masses masses demonstrated no peripancreatic or vascular invasion, though they showed a discrete margin and contour bulging. Single metastasis to the pancreas was most common, and metastatic masses had a discrete margin, with contour bulging. There was no peripancreatic or vascular invasion. If the metastasis involved a single low-attenuated mass, however, with pancreatic or biliary dilatation, it was difficult to differentiate this from primary pancreatic cancer. (author)

  17. Implementation and evaluation of two helical CT reconstruction algorithms in CIVA

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    Banjak, H.; Costin, M.; Vienne, C.; Kaftandjian, V.

    2016-02-01

    The large majority of industrial CT systems reconstruct the 3D volume by using an acquisition on a circular trajec-tory. However, when inspecting long objects which are highly anisotropic, this scanning geometry creates severe artifacts in the reconstruction. For this reason, the use of an advanced CT scanning method like helical data acquisition is an efficient way to address this aspect known as the long-object problem. Recently, several analytically exact and quasi-exact inversion formulas for helical cone-beam reconstruction have been proposed. Among them, we identified two algorithms of interest for our case. These algorithms are exact and of filtered back-projection structure. In this work we implemented the filtered-backprojection (FBP) and backprojection-filtration (BPF) algorithms of Zou and Pan (2004). For performance evaluation, we present a numerical compari-son of the two selected algorithms with the helical FDK algorithm using both complete (noiseless and noisy) and truncated data generated by CIVA (the simulation platform for non-destructive testing techniques developed at CEA).

  18. Helical CT in the primary trauma evaluation of the cervical spine: an evidence-based approach

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    Blackmore, C.C. [Washington Univ., Seattle, WA (United States). Dept. of Radiology; Center for Cost and Outcomes Research, Univ. of Washington, Seattle (United States); Dept. of Radiology, Harborview Medical Center, Seattle, WA (United States); Mann, F.A. [Washington Univ., Seattle, WA (United States). Dept. of Radiology; Harborview Injury Prevention and Research Center, University of Washington, Seattle (United States); Wilson, A.J. [Washington Univ., Seattle, WA (United States). Dept. of Radiology

    2000-11-01

    This review provides a summary of the cost-effectiveness, clinical utility, performance, and interpretation of screening helical cervical spine CT for trauma patients. Recent evidence supports the use of helical CT as a cost-effective method for screening the cervical spine in high-risk trauma patients. Screening cervical spine CT can be performed at the time of head CT to lower the cost of the evaluation, and when all short- and long-term costs are considered, CT may actually save money when compared with traditional radiographic screening. In addition to having higher sensitivity and specificity for cervical spine injury, CT screening also allows more rapid radiological clearance of the cervical spine than radiography. Patients who are involved in high-energy trauma, who sustain head injury, or who have neurological deficits are candidates for CT screening. Screening with CT may enhance detection of other potentially important injuries of the cervical region. (orig.)

  19. Three-dimensional helical CT for treatment planning of breast cancer

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    Hiramatsu, Hideko; Enomoto, Kohji; Ikeda, Tadashi [Keio Univ., Tokyo (Japan). School of Medicine] [and others

    1999-01-01

    The role of three-dimensional (3D) helical CT in the treatment planning of breast cancer was evaluated. Of 36 patients examined, 30 had invasive ductal carcinoma, three had invasive lobular carcinoma, one had DCIS, one had DCIS with minimal invasion, and 1 had Paget`s disease. Patients were examined in the supine position. The whole breast was scanned under about 25 seconds of breath-holding using helical CT (Proceed, Yokogawa Medical Systems, or High-speed Advantage, GE Medical Systems). 3D imaging was obtained with computer assistance (Advantage Windows, GE Medical Systems). Linear and/or spotty enhancement on helical CT was considered to suggest DCIS or intraductal spread in the area surrounding the invasive cancer. Of 36 patients, 24 showed linear and/or spotty enhancement on helical CT, and 22 of those 24 patients had DCIS or intraductal spread. In contrast, 12 of 36 patients were considered to have little or no intraductal spread on helical CT, and eight of the 12 patients had little or no intraductal spread on pathological examination. The sensitivity, specificity, and accuracy rates for detecting intraductal spread on MRI were 85%, 80%, and 83%, respectively. 3D helical CT was considered useful in detecting intraductal spread and planning surgery, however, a larger study using a precise correlation with pathology is necessary. (author)

  20. Severity assessment of acute pulmonary embolism: evaluation using helical CT

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    Collomb, D.; Paramelle, P.J.; Calaque, O. [Department of Radiology, CHU Grenoble, BP 218, 38043, Grenoble Cedex (France); Bosson, J.L. [Department of Statistics and Vascular diseases, CHU Grenoble, BP 218, 38043, Grenoble Cedex (France); Vanzetto, G. [Department of Cardiology, CHU Grenoble, BP 218, 38043, Grenoble Cedex (France); Barnoud, D. [Department of Medical Intensive Care, CHU Grenoble, BP 218, BP 218, 38043, Grenoble Cedex (France); Pison, C. [Department of Pulmonary Medicine, CHU Grenoble, BP 218, 38043, Grenoble Cedex (France); Coulomb, M.; Ferretti, G.

    2003-07-01

    The objective was to evaluate the helical CT (HCT) criteria that could indicate severe pulmonary embolism (PE). In a retrospective study, 81 patients (mean age 62 years) with clinical suspicion of PE explored by HCT were studied. The patients were separated into three different groups according to clinical severity and treatment decisions: group SPE included patients with severe PE based on clinical data who were treated by fibrinolysis or embolectomy (n=20); group NSPE included patients with non-severe PE who received heparin (n=30); and group WPE included patients without PE (n=31). For each patient we calculated a vascular obstruction index based on the site of obstruction and the degree of occlusion in the pulmonary artery. We noted the HCT signs, i.e., cardiac and pulmonary artery dimensions, that could indicate acute cor pulmonale. According to multivariate analysis, factors significantly correlated with the severity of PE were: the vascular obstruction index (group SPE: 54%; group NSPE: 24%; p<0.001); the maximum minor axis of the left ventricle (group SPE: 30.2 mm; group NSPE: 40.4 mm; p<0.001); the diameter of the central pulmonary artery (group SPE: 32.4 mm; group NSPE: 28.3 mm; p<0.001); the maximum minor axis of the right ventricle (group SPE: 47.5 mm; group NSPE: 42.7 mm; p=0.029); the right ventricle/left ventricle minor axis ratio (group SPE: 1.63; group NSPE: 1.09; p<0.0001). Our data suggest that hemodynamic severity of PE can be assessed on HCT scans by measuring four main criteria: the vascular obstruction index; the minimum diameter of the left ventricle; the RV:LV ratio; and the diameter of the central pulmonary artery. (orig.)

  1. Pancreatic adenocarcinoma: dual-phase helical CT with surgical and histopathologic correlation

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    Kim, Eun A; Yoon, Kwon Ha; Park, Seong Hoon; Yun, Ki Jung; Won, Jong Jin [Wonkwang University School of Medicine, Iksan (Korea, Republic of)

    2003-03-01

    To determine the accuracy of dual-phase helical CT in assessing the resectability of pancreatic ductal adenocarcinoma, and to correlate the CT findings with the surgical and histopathologic findings. Thirty patients with pathologically proven cancer of the pancreas underwent arterial-and portal-phase helical CT scanning, and in the two of these, single-level dynamic CT was performed during celiac and superior mesenteric arteriography. In 17 patients who underwent surgery for potentially resectable cancer of the pancreatic head, tumor resectability was assessed. The CT findings were analyzed and correlated with these of surgery and histopathology. In 13 (76%) of the 17 patients who underwent surgery, tumors were resectable. Their average size was 2.76 cm (arterial phase), 2.30 cm (portal phase), and 2.48 cm (pathologically determined) and the overall accuracy of helical CT for assessing resectability was 87%. In all patients, the central portion of the tumors exhibited hypoattenuation at both phases; the peripheral portion showed hypoattenuation at the arterial phase and iso- (n=10) or hyperattenuation (n=3) at the portal phase. Single-level dynamic CT depicted a persistently hypoattenuating central portion and progressive and prolonged enhancement of the periphery. CT-histopathologic correlation showed that central hypoattenuation indicated the presence of tumor cells, necrosis (n=3) and mucin (n=4), while the peripheral iso- or hyperattenuated areas seen at the portal phase represented fibrosis and inflammatory infiltration. Histopathologic examination revealed tumoral infiltration of peripancreatic fat tissue (n=11) and microvascular invasion of major peripancreatic vessels (n=7). The dual-phase helical CT is useful in the determination of resectability in pancreas cancer and CT findings represent well the histopathologic features of pancreas cancer.

  2. Rupture of an aneurysm of the coronary sinus of Valsalva: diagnosis by helical CT angiography

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    Azarine, A.; Lions, C.; Beregi, J.P. [Dept. of Vascular Surgery, Hopital Cardiologique, CHRU de Lille (France); Koussa, M. [Dept. of Vascular Radiology, Hopital Cardiologique, CHRU de Lille (France)

    2001-08-01

    A 75-year-old man presented with a 5-day history of upper chest discomfort. On auscultation, there was a systolic murmur in the left parasternal area that radiated to the apex. Electrocardiography showed flat T waves in the anterior precordial leads. Chest X ray revealed mediastinal enlargement. Transthoracic echocardiography showed a dilated proximal ascending aorta with moderate aortic regurgitation. A contrast-enhanced helical CT scan, performed to eliminate an aortic dissection, showed a ruptured left coronary sinus of Valsalva aneurysm, confirmed at surgery. This case highlights the fact that helical CT, in patients with suspected aortic dissection, may reveal other pathology that accounts for the clinical presentation. (orig.)

  3. Effect of CT contrast on volumetric arc therapy planning (RapidArc and helical tomotherapy) for head and neck cancer

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    Liu, Alan J.; Vora, Nayana [Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA (United States); Suh, Steve [Department of Radiation Physics, City of Hope National Medical Center, Duarte, CA (United States); Liu, An, E-mail: aliu@coh.org [Department of Radiation Physics, City of Hope National Medical Center, Duarte, CA (United States); Schultheiss, Timothy E. [Department of Radiation Physics, City of Hope National Medical Center, Duarte, CA (United States); Wong, Jeffrey Y.C. [Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA (United States)

    2015-04-01

    The objectives of the study were to evaluate the effect of intravenous contrast in the dosimetry of helical tomotherapy and RapidArc treatment for head and neck cancer and determine if it is acceptable during the computed tomography (CT) simulation to acquire only CT with contrast for treatment planning of head and neck cancer. Overall, 5 patients with head and neck cancer (4 men and 1 woman) treated on helical tomotherapy were analyzed retrospectively. For each patient, 2 consecutive CT scans were performed. The first CT set was scanned before the contrast injection and secondary study set was scanned 45 seconds after contrast. The 2 CTs were autoregistered using the same Digital Imaging and Communications in Medicine coordinates. Tomotherapy and RapidArc plans were generated on 1 CT data set and subsequently copied to the second CT set. Dose calculation was performed, and dose difference was analyzed to evaluate the influence of intravenous contrast media. The dose matrix used for comparison included mean, minimum and maximum doses of planning target volume (PTV), PTV dose coverage, and V{sub 45} {sub Gy}, V{sub 30} {sub Gy}, and V{sub 20} {sub Gy} organ doses. Treatment planning on contrasted images generally showed a lower dose to both organs and target than plans on noncontrasted images. The doses for the points of interest placed in the organs and target rarely changed more than 2% in any patient. In conclusion, treatment planning using a contrasted image had insignificant effect on the dose to the organs and targets. In our opinion, only CT with contrast needs to be acquired during the CT simulation for head and neck cancer. Dose calculations performed on contrasted images can potentially underestimate the delivery dose slightly. However, the errors of planning on a contrasted image should not affect the result in clinically significant way.

  4. Analysis of enhancement pattern of sellar and parasellar tumors using two-phase helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Ji Young; Na, Dong Gyu; Roh, Hong Gee; Byun, Hong Sik; Ryoo, Jae Wook [Medical School of Sungkyunkwan Univ., Seoul (Korea, Republic of)

    2002-01-01

    To assess the enhancement patterns of sellar and parasellar tumors at two-phase helical CT. Thirty-two patients with pathologically proven sellar and parasellar tumors (meningioma (n=17), pituitary mocroadenoma (n=6), neurogenic tumor (n=5), cavernous angioma (n=1), chondrosarcoma (n=1), osteosarcoma (n=1), sphenoid carcinoma (n=1)) were included in this study. Two-phase helical CT was performed after the injection of 90 mL of contrast materials at a rate of 3 mL/sec. Transverse helical CT scans were obtained during the early and late phases, with scannin dealys of 30 and 120 seconds, respectively. Delayed coronal images were obtained after delayed axial images. Attenuation change and the enhancement patterns of the tumors were visually assessed; the former was also assessed quantitatively as the ratio of the CT number at late-phase axial and coronal scanning to that at early-phase scanning. Visual assessment of two-phase helical CT images revealed decreased attenuation in all 17 meningiomas, no change in all six pituitary macroadenomas and increased attenuation in 5 all five neurogenic tumors on late-phase axial scans as compared with early phase scans. Coronal images showed decreased attenuation in all 17 meningiomas, increased attenuation in all five neurogenic tumors and no change in four pituitary macroadenomas (66.7%). The ratio of CT numbers was significantly different between meningiomas, neurogenic tumors and pituitary macroadenomas (p< 0.05). According to their histopathology, sellar and parasellar tumors showed characteristic enhancement patterns at two-phase helical CT. An analysis of the observed enhancement patterns can be useful in the differential diagnosis of juxtasellar tumors.

  5. Thin section helical CT findings of klastskin tumor and benign stricture: cholangiographic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Guk Myeong; Han, Joon Koo; Kim, Tae Kyoung; Choi, Byung Ihn; Kim, Sun Whe; Cho, Yun Ku; Han, Man Chung; Yeon, Kyung Mo [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

    1997-10-01

    The purpose of this study was (1) to describe the thin section helical CT findings of hilar cholangiocarcinoma and of benign strcture, and to discuss the differential points between the two disease entities and (2) using cholangiographic correlation, to evaluate the diagnostic accuracy of helical CT in determining the extent of hilar cholangiocarcinoma. Twenty-seven patients with hilar cholangiocarcinoma and eight with benign biliary dilatation were studied. All except four with hilar cholangiocarcinoma, who underwentCT using a conventional scanner, were studied with two-phase helical CT. In all patients, cholangiographs were obtained by digital fluoroscopy after the injection of contrast materials into PTBD catheters. The level of obstruction was classified according to Bismuth, and 35 CT scans were studied blindly and retrospectively by two radiologists. The findings were analyzed for the presence of tumor, and then divided into two groups(cholangiocarcinomas and benign strictures), and the positive predictive value was calculated. The CT images of klatskin tumor were analyzed with special emphasis on the level and shape of the hilar obstruction. The level of biliary obstruction and extent of the tumor were carefully correlated with the results of cholangiography. Thin-section spiral CT correctly identified all tumor mass as a focal wall thickening obliterating the lumen. On arterial/portal phase CT scanning, 81% of infilterative tumors showed high attenuation. In all patients, differentiation between benign stricture and klaskin tumor was possible;correct identification of the level of obstruction and extent of tumor, according to Bismuth's classification, was possible in 63% of cases. For correct diagnosis of hilar cholangiocarcinoma and differentiation of benign stricture, helical CT was highly accurate and effective. Because of limital Z-axis resolution, however, the exact intraductal extent of the tumor was less accorately diagnosed.=20.

  6. Bile duct complications of hepatic arterial infusion chemotherapy evaluated by helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Phongkitkarun, S. [Department of Diagnostic Radiology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)]. E-mail: rasih@mahidol.ac.th; Kobayashi, S. [Department of Diagnostic Radiology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Varavithya, V. [Department of Diagnostic Radiology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Huang, X. [Department of Biostatistics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Curley, S.A. [Department of Surgical Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Charnsangavej, C. [Department of Diagnostic Radiology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

    2005-06-01

    AIM: To describe the imaging findings of bile duct complications of hepatic arterial infusion chemotherapy (HAIC) using helical CT, to set diagnostic criteria, to develop a CT grading system, and to correlate these with clinical findings and laboratory data. METHODS: Follow-up helical CT of the abdomen was performed every 3 months for 60 patients receiving HAIC. Three radiologists reviewed all CT studies before and after treatment, using either the picture archiving and communication system or hard copies. The findings of bile duct abnormalities were correlated with findings from other imaging techniques, clinical symptoms and laboratory data. RESULTS: Bile duct abnormalities developed in 34 (57%) of cases either during HAIC or 1 to 12 months after treatment. In 14 (41%) of these 34 patients, enhancement of the hepatic parenchyma along the dilated bile duct or in the segmental or lobar distribution was observed. In 43 cases (72%), normal or abnormal alkaline phosphatase levels were consistent with normal or abnormal CT findings, respectively. Increasing alkaline phosphatase and bilirubin levels were related to CT grade. CONCLUSION: Imaging findings of bile duct complications of HAIC are similar to those of primary sclerosing cholangitis, and correlate well with abnormal clinical and laboratory data. In the presence of such clinical abnormalities, thin-section helical CT with careful review of the imaging studies helps to determine the correct diagnosis, monitor the changes and guide appropriate treatment.

  7. Radiologic investigation of renal colic: unenhanced helical CT compared with excretory urography.

    Science.gov (United States)

    Sourtzis, S; Thibeau, J F; Damry, N; Raslan, A; Vandendris, M; Bellemans, M

    1999-06-01

    Our aim was to compare unenhanced helical CT and excretory urography in the assessment of patients with renal colic. Fifty-three of 70 consecutive patients with acute signs of renal colic were prospectively examined with unenhanced helical CT, which was followed immediately by excretory urography. Two radiologists who were unaware of the findings independently interpreted these examinations to determine the presence or absence of ureteral obstruction. On all CT scans that had positive findings for ureteral stones or obstruction, we looked for secondary signs of obstruction (perinephric or periureteral fat stranding, ureteral wall edema, ureteral dilatation, and blurring of renal sinus fat). A stone was recovered in 45 of the 53 patients, nine before and 36 after imaging. The latter 36 patients had their stones identified on CT, whereas only 24 patients had their stones identified on excretory urography. Eight patients without stone disease had normal ureters on both CT and excretory urography. Of the 45 patients who had stone disease, 26 had ureteral dilatation on both CT and excretory urography, and 36 patients who recovered a stone after CT had secondary signs of obstruction. Of the nine patients who recovered a stone before CT, three had secondary signs of obstruction. Two patients had periureteral fat stranding, ureteral wall edema, and renal sinus fat blurring. One patient had only ureteral wall edema. Compared with excretory urography, unenhanced helical CT is better for identifying ureteral stones in patients with acute ureterolithiasis. Secondary CT signs of obstruction, including renal sinus fat blurring, were frequently present even when the stone was eliminated before imaging.

  8. Imaging of aortic dissection by helical computed tomography (CT)

    Energy Technology Data Exchange (ETDEWEB)

    Willoteaux, Serge; Lions, Christophe; Gaxotte, Virginia; Negaiwi, Ziad; Beregi, J.P. [CHRU de Lille, Department of Cardiovascular Radiology, Hopital Cardiologique, Lille (France)

    2004-11-01

    Aortic dissection is the most frequent cause of aortic emergency, and its outcome is still frequently fatal. The management of this pathology has changed with the development of endovascular means. Nowadays, imaging modalities are helpful in management decision-making by providing information such as identification of entry tears along the aorta and involvement of the visceral branches of the abdominal aorta. Multi-slice CT scanning now appears to be the modality of choice for complete examination of the entire aorta. We review the parameters of image acquisition and contrast injection; appearances on CT of acute and chronic dissection are illustrated. Diagnostic pitfalls in CT imaging of acute dissection are discussed. Imaging of the post-surgical aorta and of chronic dissection is outlined. Intra-mural hematoma and penetrating aortic ulcer are subtypes of aortic dissection, and their appearances on CT scanning are also presented. (orig.)

  9. Helical CT angiography : A single imaging modality to evaluate a live renal donor

    Directory of Open Access Journals (Sweden)

    Waheed Zaman

    2002-01-01

    Conclusions: Helical CT angiography, which is highly specific for arterial and venous anatomy as well as other anatomical and functional details, can become the single imaging modality for preoperative assessment of poten-tial donors in place of conventional angiography and IVU. CTA, being minimally invasive and cost effective, is well accepted by a normal healthy donor

  10. Non-contrast thin-section helical CT of urinary tract calculi in children

    Energy Technology Data Exchange (ETDEWEB)

    Strouse, Peter J. [Section of Pediatric Radiology, University of Michigan Medical Center, Ann Arbor, MI (United States); Bates, Gregory D. [Department of Radiology, Columbus Children' s Hospital, Columbus, OH (United States); Bloom, David A. [Department of Pediatric Imaging, Children' s Hospital of Michigan, Detroit, MI (United States); Goodsitt, Mitchell M. [Department of Radiology, University of Michigan Medical Center, Ann Arbor, MI (United States)

    2002-05-01

    Background: Non-contrast thin-section helical CT has gained acceptance for the diagnosis of urinary tract calculi in adults, but experience with the technique in children is limited. Purpose: To evaluate the utility of non-contrast thin section helical CT for the diagnosis of urinary tract calculi in children. Materials and methods: Radiology databases at three pediatric institutions were searched to identify all pediatric patients evaluated by ''renal stone'' protocol CT scans (no oral or intravenous contrast, scans covering the entire urinary tract obtained in helical mode with narrow collimation (< 5 mm)). CT scans were reviewed for the primary finding of urinary tract calculi, for secondary signs of acute urinary tract obstruction and for evidence of alternative diagnoses. Medical records were reviewed to determine clinical presentation and to confirm the eventual diagnosis. Results: One hundred thirty-seven scans of 113 children (mean age: 11.2 years) were studied. Thirty-eight of 94 examinations (40%) performed on 82 children for acute pain and/or hematuria showed ureteral calculi. Alternative diagnoses were suggested by CT on 16 scans (17%). Twenty-eight scans were performed on 10 asymptomatic children with known calculus disease confirming renal stone burden on 21 scans (75%) and persistent ureteral calculi on 6 scans (21%). Upper tract calculi were demonstrated on 10 of 15 scans (67%) performed to evaluate for calculi in patients with known non-calculus genitourinary tract abnormalities. Conclusions: Non-contrast thin section helical CT is a useful method to diagnose urinary tract calculi in children. Radiation dose in this retrospective study may exceed the lowest possible radiation dose for diagnostic accuracy. Further research is needed to optimize CT imaging parameters, while maintaining diagnostic accuracy and minimizing radiation dose. (orig.)

  11. Three-dimensional CT imaging with a helical scan on temporal bone

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Honghan; Hiraishi, Kumiko; Uesugi, Yasuo; Sakakura, Atsushi; Yoshikawa, Shuji; Shimizu, Takaya; Sueyoshi, Kozo; Narabayashi, Isamu [Osaka Medical Coll., Takatsuki (Japan)

    1996-06-01

    To evaluate the usefulness of three-dimensional (3D) CT on the lesions of temporal bone, we studied 19 patients with disorders on the region of temporal bone by high speed helical CT. The results showed that 8 patients with congenital hearing disorder had deficiency of the auditory ossicles, 2 patients with chronic otitis media had deformity and shortness of the auditory ossicles, 4 patients with trauma had fracture of the temporal bone (1 patient was complicated by doubtful fracture of the incus), 5 patients (4 patients with acquired hearing disorder and 1 patient with otorrhea) had space-occupying lesions. 3-D helical CT could detect abnormal findings on all the patients and it was an important examination for the temporal bone. (author)

  12. The usefulness of three-dimensional helical CT for the detection of abnormalities of the auditory ossicles

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Honghan; Hiraishi, Kumiko; Uesugi, Yasuo; Shimizu, Tadafumi; Narabayashi, Isamu [Osaka Medical Coll., Takatsuki (Japan)

    1996-04-01

    To evaluate the usefulness of three-dimensional (3D) helical CT for the detection of abnormalities of the auditory ossicles, 3D helical CT of the middle ear was performed in seven patients with hearing disorder. It revealed that 4 patients had congenital deficiency of the auditory ossicles, 2 patients with chronic otitis media had shortening of the incus and one patient with head injury had doubtful fracture of the incus. This study indicated that 3D helical CT of the middle ear can represent the auditory ossicles objectively and can offer detailed diagnosis. (author).

  13. Acute ureterolithiasis: Incidence of secondary signs on unenhanced helical CT and influence on patient management

    Energy Technology Data Exchange (ETDEWEB)

    Ege, G. E-mail: gurkanege@yahoo.com; Akman, H.; Kuzucu, K.; Yildiz, S

    2003-12-01

    AIM: The purpose of this study was to determine the incidence of secondary signs associated with ureteral stones on unenhanced helical computed tomography (CT) of patients with acute renal colic, and to correlate these with patient management and outcome. MATERIALS AND METHODS: One hundred and ten patients with ureterolithiasis were evaluated prospectively for the secondary signs of obstruction on unenhanced helical CT. Our attention was focused primarily on the presence or absence of seven secondary signs on unenhanced helical CT, including hydronephrosis, unilateral renal enlargement, perinephric oedema, unilateral absence of the white pyramid, hydroureter, periureteral oedema and lateroconal fascial thickening. RESULTS: Of the 110 patients, 91 (82.7%) had hydroureter, 88 (80%) had hydronephrosis, 65 (59%) had periureteric oedema and 63 (57.2%) had unilateral renal enlargement. Ninety stones passed spontaneously and 21 required intervention. CONCLUSION: Secondary signs of urinary tract obstruction are useful and supportive findings in interpretation of the CT examination. In our experience, the most reliable signs indicating ureteral obstruction are hydroureter, hydronephrosis, periureteral oedema and unilateral renal enlargement, respectively. In addition, stones larger than 6 mm, located within the proximal two thirds of the ureter, and seen associated with five or more the secondary signs of obstruction, are more likely to require endoscopic removal and/or lithotripsy.

  14. Acquiring 4D thoracic CT scans using a multislice helical method

    Science.gov (United States)

    Keall, P. J.; Starkschall, G.; Shukla, H.; Forster, K. M.; Ortiz, V.; Stevens, C. W.; Vedam, S. S.; George, R.; Guerrero, T.; Mohan, R.

    2004-05-01

    Respiratory motion degrades anatomic position reproducibility during imaging, necessitates larger margins during radiotherapy planning and causes errors during radiation delivery. Computed tomography (CT) scans acquired synchronously with the respiratory signal can be used to reconstruct 4D CT scans, which can be employed for 4D treatment planning to explicitly account for respiratory motion. The aim of this research was to develop, test and clinically implement a method to acquire 4D thoracic CT scans using a multislice helical method. A commercial position-monitoring system used for respiratory-gated radiotherapy was interfaced with a third generation multislice scanner. 4D cardiac reconstruction methods were modified to allow 4D thoracic CT acquisition. The technique was tested on a phantom under different conditions: stationary, periodic motion and non-periodic motion. 4D CT was also implemented for a lung cancer patient with audio-visual breathing coaching. For all cases, 4D CT images were successfully acquired from eight discrete breathing phases, however, some limitations of the system in terms of respiration reproducibility and breathing period relative to scanner settings were evident. Lung mass for the 4D CT patient scan was reproducible to within 2.1% over the eight phases, though the lung volume changed by 20% between end inspiration and end expiration (870 cm3). 4D CT can be used for 4D radiotherapy, respiration-gated radiotherapy, 'slow' CT acquisition and tumour motion studies.

  15. Improved detection of renal pathologic features on multiphasic helical CT compared with IVU in patients presenting with microscopic hematuria.

    Science.gov (United States)

    Lang, Erich K; Macchia, Richard J; Thomas, Raju; Watson, Richard A; Marberger, Michael; Lechner, Gerhard; Gayle, Brian; Richter, Frank

    2003-03-01

    To examine the virtues of multiphasic helical computed tomography (CT) in the diagnosis of upper urinary tract lesions refractory to identification by intravenous urography (IVU). A total of 86 patients (59 men and 27 women), 27 to 88 years old, with microscopic hematuria and negative IVU findings were examined with multiphasic helical CT consisting of a pre-enhancement, late arterial-early cortical-medullary, nephrographic, and excretory phase helical CT of the kidneys, using 3 to 5-mm collimation and 7.5-mm/s table feed. The multiphasic helical CT was conclusive in 84 lesions. Twenty-five cases of early papillary and medullary necrosis, 7 of 8 inflammatory lesions, 3 caliceal diverticula, 1 lupus nephritis, 26 small calculi, 2 medullary sponge kidney, 5 vascular anomalies, and 3 infarcts presented with characteristic manifestations on CT but lacked findings on IVU. Similarly 8 of 9 small malignant neoplasms, 2 small benign neoplasms, and 2 small cysts produced no detectable findings on IVU but were readily diagnosed on helical CT. Characteristic findings, particularly on late arterial, early corticomedullary, parenchymal, and excretory phase helical CT make possible the diagnosis of early inflammatory disease, small masses and neoplastic lesions, and vascular abnormalities. Limited resolution (needed to identify small calculi) and the lack of ability to capture phases significantly reduce the diagnostic ability of IVU.

  16. Emergencies in the retroperitoneum: assessment of spread of disease by helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Scialpi, M. E-mail: michelescialpi@libero.it; Scaglione, M.; Angelelli, G.; Lupattelli, L.; Resta, M.C.; Resta, M.; Rotondo, A

    2004-04-01

    Acute pancreatitis, leaking abdominal aortic aneurysm, and renal trauma frequently occur in the setting of patients with abdominal nontraumatic and traumatic injury; it represents the most urgent conditions that may determine the presence of fluid collections or haematoma in the retroperitoneum. Single spiral CT and multidetector-row CT (MDCT) play an important role in diagnosis of retroperitoneal emergencies, providing useful informations on the type, site, extent and management of the fluid collections. An accurate CT assessment requires the awareness of the existence of dissectable retroperitoneal fascial planes. Fluid collections or haematoma tends to escape the retroperitoneal site of origin into planes extend from the diaphragm to the pelvic floor. We assess the multicompartimental anatomy of the retroperitoneum and the pathway of spread of the most frequent retroperitoneal fluid collections or haematoma by helical CT.

  17. Diagnostic performance of reformatted isotropic thin-section helical CT images in the detection of superior semicircular canal dehiscence.

    Science.gov (United States)

    Sparacia, Gianvincenzo; Iaia, Alberto

    2017-06-01

    Purpose The purpose of this article is to assess the diagnostic performance of computed tomography (CT) reformatted images for detection of superior semicircular canal (SSC) dehiscence. Material and methods Forty-two patients, with sound- and/or pressure-induced vestibular symptoms, and 42 control participants underwent helical CT examination with a highly collimated beam (0.5 mm). Reformatted images of the vestibular labyrinth were obtained in the standard axial and coronal planes (group A images), and in a plane parallel and perpendicular to the SSC (group B images). Diagnostic performance obtained by evaluating the group A images alone and the group B images alone was analyzed by using the area under the receiver operating characteristic curve (AUC). Results The diagnostic performance of group A images was AUC = 0.929 with an overall accuracy of 92.9%. The diagnostic performance of group B images was AUC = 0.988 with an overall accuracy of 98.8%. The evaluation of group B images alone showed an improved diagnostic performance over the group A images alone. Conclusion Thin-section 0.5-mm collimation CT with reformatted images oriented in the plane parallel and perpendicular to the SSC improves diagnostic accuracy in assessing for SSC dehiscence in comparison to CT images with reconstructions limited to traditional axial and coronal planes.

  18. Detectability of cerebral aneurysms and surrounding vessels by three-dimensional evaluation using helical scanning CT (HES-CT)

    Energy Technology Data Exchange (ETDEWEB)

    Ogura, Yuko; Katada, Kazuhiro; Sano, Hirotoshi; Kato, Yoko; Kanno, Tetsuo; Takeshita, Gen; Koga, Sukehiko (Fujita Health Univ., Toyoake, Aichi (Japan))

    1994-09-01

    Helical scanning CT (HES-CT) is a new technique to enable high-speed volumetric data acquisition. We have applied HES-CT to the diagnosis of cerebral vascular diseases. In our experience, the relationship between the scanning parameters of HES-CT and image quality was complex and reciprocal, so that optimization of the parameters according to the clinical demands was essential. We compared HES-CT with conventional cerebral angiography to determine the detectability of the aneurysm and surrounding vessels, and sought the optimal parameters to delineate small vessels. All aneurysms were detected in multiplanar reconstruction (MPR) images. The smallest one was 3 x 4 mm. MPR images were found to have some advantages over conventional cerebral angiography in delineation of intracranial aneurysms: (1) scanning was over in a short time (30 s), (2) the relationship between the aneurysm and surrounding vessels was easily recognized, (3) the diameter of the neck could be measured, because the neck of the aneurysm and parent artery could be imaged on the same plane without overlapping another vessel, (4) calcified lesions on the aneurysmal wall were detected, and (5) HES-CT was done safety without arterial puncture. However, the detectability of unknown aneurysm was less than the detectability of known aneurysm in MPR images. The 180deg interpolation algorithm and 1 mm slice were effective in detecting small vessels. However, vessels with a diameter less than 1 mm could not be detected by HES-CT. HES-CT was considered to be useful as a supplementary examination to conventional angiography for the diagnosis of intracranial aneurysms. (author).

  19. Correction for human head motion in helical x-ray CT

    Science.gov (United States)

    Kim, J.-H.; Sun, T.; Alcheikh, A. R.; Kuncic, Z.; Nuyts, J.; Fulton, R.

    2016-02-01

    Correction for rigid object motion in helical CT can be achieved by reconstructing from a modified source-detector orbit, determined by the object motion during the scan. This ensures that all projections are consistent, but it does not guarantee that the projections are complete in the sense of being sufficient for exact reconstruction. We have previously shown with phantom measurements that motion-corrected helical CT scans can suffer from data-insufficiency, in particular for severe motions and at high pitch. To study whether such data-insufficiency artefacts could also affect the motion-corrected CT images of patients undergoing head CT scans, we used an optical motion tracking system to record the head movements of 10 healthy volunteers while they executed each of the 4 different types of motion (‘no’, slight, moderate and severe) for 60 s. From these data we simulated 354 motion-affected CT scans of a voxelized human head phantom and reconstructed them with and without motion correction. For each simulation, motion-corrected (MC) images were compared with the motion-free reference, by visual inspection and with quantitative similarity metrics. Motion correction improved similarity metrics in all simulations. Of the 270 simulations performed with moderate or less motion, only 2 resulted in visible residual artefacts in the MC images. The maximum range of motion in these simulations would encompass that encountered in the vast majority of clinical scans. With severe motion, residual artefacts were observed in about 60% of the simulations. We also evaluated a new method of mapping local data sufficiency based on the degree to which Tuy’s condition is locally satisfied, and observed that areas with high Tuy values corresponded to the locations of residual artefacts in the MC images. We conclude that our method can provide accurate and artefact-free MC images with most types of head motion likely to be encountered in CT imaging, provided that the motion can

  20. Correction for human head motion in helical x-ray CT.

    Science.gov (United States)

    Kim, J-H; Sun, T; Alcheikh, A R; Kuncic, Z; Nuyts, J; Fulton, R

    2016-02-21

    Correction for rigid object motion in helical CT can be achieved by reconstructing from a modified source-detector orbit, determined by the object motion during the scan. This ensures that all projections are consistent, but it does not guarantee that the projections are complete in the sense of being sufficient for exact reconstruction. We have previously shown with phantom measurements that motion-corrected helical CT scans can suffer from data-insufficiency, in particular for severe motions and at high pitch. To study whether such data-insufficiency artefacts could also affect the motion-corrected CT images of patients undergoing head CT scans, we used an optical motion tracking system to record the head movements of 10 healthy volunteers while they executed each of the 4 different types of motion ('no', slight, moderate and severe) for 60 s. From these data we simulated 354 motion-affected CT scans of a voxelized human head phantom and reconstructed them with and without motion correction. For each simulation, motion-corrected (MC) images were compared with the motion-free reference, by visual inspection and with quantitative similarity metrics. Motion correction improved similarity metrics in all simulations. Of the 270 simulations performed with moderate or less motion, only 2 resulted in visible residual artefacts in the MC images. The maximum range of motion in these simulations would encompass that encountered in the vast majority of clinical scans. With severe motion, residual artefacts were observed in about 60% of the simulations. We also evaluated a new method of mapping local data sufficiency based on the degree to which Tuy's condition is locally satisfied, and observed that areas with high Tuy values corresponded to the locations of residual artefacts in the MC images. We conclude that our method can provide accurate and artefact-free MC images with most types of head motion likely to be encountered in CT imaging, provided that the motion can be

  1. Clinical usefulness of helical CT three-dimensional images in blow-out fractures

    Energy Technology Data Exchange (ETDEWEB)

    Takeno, Naokazu; Honda, Kouichi; Ohiwa, Akira [Keiseigeka Memorial Hospital, Sapporo, Hokkaido (Japan); Miyashita, Souji; Sugihara, Tsuneki; Funayama, Emi; Maeda, Kazuhiko

    1996-12-01

    Since the bone of the orbital floor is very thin, it was previously impossible to visualize bone deficits and bone fracture lines of the orbital floor accurately in three-dimensional (3D) CT images. Since the analytical ability of CT and 3D image reconstitution have improved, however, CT imaging of thin bone has become possible. We used CT photography and 3D image reconstruction in 19 cases before surgery to correct blow-out fracture. We used the Toshiba Corporation helical CT system (X-Vigor, version 5.0A) and filmed an area 3-4 cm wide in the orbital region, mainly on the orbital floor. The X-Tension workstation (Toshiba) was used for 3D image reconstruction. All cases were filmed in 0.5-mm slices. CT scanning time was approximately 60 seconds. There were very few artifacts in the 3D images. Small bone deficits and minute bone fracture lines could be observed on the 3D images, and it was also possible to change the visual angle. The CT images were faithful, their reliability was good, and they were clinically useful. In 8 cases in which a silicon sheet was used for reconstruction of the orbital floor, 3D images were also used for postoperative evaluation. The silicon sheets used to reconstruct bone deficits could be selectively viewed on the image and their condition determined 3D CT images are therefore considered useful in both pre- and postoperative evaluation of blow-out fractures. We have utilized these 3D CT images in the evaluation of zygomatic bone and other facial fractures in addition to blow-out fractures. (author)

  2. Use of helical CT in assessment of crossing vessels in pelviureteric junction obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Lacey, N.A.; Massouh, H

    2000-03-01

    AIM: The purpose of this study is to confirm the accuracy of non-invasive helical computed tomography (CT) with multiplanar reformatting in the diagnosis of crossing vessels in patients with pelviureteric junction (PUJ) obstruction. MATERIALS AND METHODS: Nineteen patients with confirmed PUJ obstruction underwent CT of the renal area with intravenous contrast medium. Patients shown to have crossing vessels had to undergo a pyeloplasty by open surgery or laparoscopy. Patients with no vessels could have their PUJ obstruction safely treated with less invasive techniques such as balloon dilatation. RESULTS: Fourteen patients were shown to have crossing vessels. Of these, 10 had their relationship to the PUJ confirmed at a subsequent laparotomy. Of the remaining four patients, one was lost to follow-up and two were unwell due to unrelated disease. The other patient had already had a vessel moved at a previous laparotomy. Of the five patients without obstructing vessels, two were confirmed not to have a related vessel at laparotomy, one has undergone balloon dilatation and the other two were lost to follow-up. CONCLUSION: Helical CT is an accurate and non-invasive method of demonstrating crossing vessels in PUJ obstruction. Diagnosis of these vessels has a major role in the choice of therapeutic treatment. Lacey, N.A., Massouh, H. (2000)

  3. Dynamic multislice helical CT of maxillomandibular lesions. Distinction of ameloblastomas from other cystic lesions

    Energy Technology Data Exchange (ETDEWEB)

    Tozaki, Mitsuhiro; Hayashi, Katsuhiko; Fukuda, Kunihiko [Jikei Univ., Tokyo (Japan). School of Medicine

    2001-10-01

    The purpose of this study was to evaluate the clinical usefulness of dynamic multislice helical CT in differentiating ameloblastoma from other cystic lesions in cases of maxillomandibular cystic lesions. The study included 32 patients with maxillomandibular cystic lesions (ameloblastoma [n=6], myxofibroma [n=1], odontogenic keratocyst [n=3], dentigerous cyst [n=11], radicular cyst [n=11], and paradental cyst [n=2]). Dynamic study was performed before and 30 sec, and 90 sec after intravenous contrast medium administration. CT density values and percentage of density increase were calculated at 30 and 90 sec. In five cases of ameloblastoma, a rapidly enhancing area was detected within the cystic lesions at 30 sec, while no apparent rapid enhancement was seen in the other cystic lesions. Three cysts showed gradual enhancement in the marginal area at 90 sec. Comparing ameloblastoma and other kinds of cysts, we found significant differences in the percentage of density increase at 30 sec (p<0.01) and 90 sec (p<0.05). Dynamic multislice helical CT is useful in the diagnosis of cystic lesions of the maxillomandibular region, especially in the detection of neovascularities in ameloblastoma. (author)

  4. Memory-efficient algorithm for stored projection and backprojection matrix in helical CT.

    Science.gov (United States)

    Guo, Minghao; Gao, Hao

    2017-04-01

    Iterative image reconstruction is often time-consuming, especially for helical CT. The calculation of X-ray projections and backprojections are computationally expensive. Although they can be significantly accelerated by parallel computing (e.g., via graphics processing unit (GPU)), they have to be calculated numerous times on-the-fly (OTF) during iterative image reconstruction due to insufficient memory storage. In this work, the memory-efficient algorithm for stored system matrix (SSM) is developed for both projections and backprojections to avoid repeated OTF computations of system matrices. The SSM algorithm is based on the shift-invariance for projection and backprojection under a rotating coordinate. As a result, the size of projection and backprojection matrices can be significantly reduced and fully stored in memory. The proposed method can be readily incorporated into iterative reconstruction algorithm with minor modification, i.e., by replacing OTF for SSM. Rigorous mathematical analysis is carried out to establish the shift-invariance for ray-driven projection and pixel-driven backprojection. Numerical results via GPU suggest that the proposed SSM method has improved computational efficiency from the OTF method, i.e., by three- to sixfold acceleration for the projection and 3- to 16-fold acceleration for the backprojection respectively for helical CT. We propose a memory-efficient SSM algorithm for projections and backprojections so that system matrices can be fully stored on the state-of-the-art GPU to facilitate the rapid iterative helical CT image reconstruction. © 2017 American Association of Physicists in Medicine.

  5. Oral contrast-enhanced three-dimensional helical-CT cholangiography: clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Stabile Ianora, Amato Antonio; Memeo, Maurizio; Scardapane, Arnaldo; Rotondo, Antonio; Angelelli, Giuseppe [Department of Radiology, University Hospital-Policlinico of Bari, Piazza Giulio Cesare 11, 70124 Bari (Italy)

    2003-04-01

    Our objective was to define the possibility of using oral-contrast-enhanced helical CT for the assessment of patients with cholecystolithiasis and of cholecystectomized symptomatic patients. Twenty-seven patients with cholecystolithiasis and 20 with a painful abdominal symptomatology after cholecystectomy (12 laparoscopic and 8 laparotomic) were recruited for this study. Cholangio-CT was performed 12-14 h after oral administration of 6 g of hyopanoic acid. The acquired data were then transferred to a second workstation and 3D reconstruction of the biliary tract was obtained. In all the cases the extrahepatic bile ducts were recognizable. Seven patients had no gallbladder opacification: CT images showed in 3 cases an infundibular stone and in 4 cases sclero-atrophic gallbladder. The intrahepatic bile ducts were visible in 21 of 27 patients with lithiasis and in 14 of 20 cholecystectomized patients. In 5 cholecystectomized patients cholangio-CT demonstrated the presence of residual choledochal or intrahepatic stones. In 3 cholecystectomized patients 3D reconstruction allowed identification of a long and winding stump of the cystic duct. Cholangio-CT is a non-invasive method to evaluate the biliary tract in patients who cannot be subjected to cholangio-MR, or as a preliminary to endoscopic retrograde cholangiopancreatography in cases of doubtful diagnosis after US and cholangio-MR. (orig.)

  6. Preoperative evaluation of renal anatomy and renal masses with helical CT, 3D-CT and 3D-CT angiography.

    Science.gov (United States)

    Toprak, Uğur; Erdoğan, Aysun; Gülbay, Mutlu; Karademir, Mehmet Alp; Paşaoğlu, Eşref; Akar, Okkeş Emrah

    2005-03-01

    The aim of this prospective study was to determine the efficacy of three-dimensional computed tomography (3D-CT) and three-dimensional computed tomographic angiography (3D-CTA) that were reconstructed by using the axial images of the multiphasic helical CT in the preoperative evaluation of renal masses and demonstration of renal anatomy. Twenty patients that were suspected of having renal masses upon initial physical examination and ultrasonographic evaluation were examined through multiphasic helical CT. Two authors executed CT evaluations. Axial images were first examined and then used to reconstruct 3D-CT and 3D- CTA images. Number, location and size of the renal masses and other findings were noted. Renal vascularization and relationships of the renal masses with the neighboring renal structures were further investigated with 3D-CT and 3D-CTA images. Out of 20 patients, 13 had histopathologically proven renal cell carcinoma. The diagnoses of the remaining seven patients were xanthogranulomatous pyelonephritis, abscess, simple cyst, infected cyst, angiomyolipoma, oncocytoma and arteriovenous fistula. In the renal cell carcinoma group, 3 patients had stage I, 7 patients had stage II, and 3 patients had stage III disease. Sizes of renal cell carcinoma masses were between 23 mm to 60 mm (mean, 36 mm). Vascular invasion was shown in 2 renal cell carcinoma patients. Collecting system invasion was identified in 11 of 13 renal cell patients. These radiologic findings were confirmed with surgical specimens. Three-dimensional CT and 3D-CTA are non-invasive, effective imaging techniques for the preoperative evaluation of renal masses.

  7. Motion tolerant iterative reconstruction algorithm for cone-beam helical CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hisashi; Goto, Taiga; Hirokawa, Koichi; Miyazaki, Osamu [Hitachi Medical Corporation, Chiba-ken (Japan). CT System Div.

    2011-07-01

    We have developed a new advanced iterative reconstruction algorithm for cone-beam helical CT. The features of this algorithm are: (a) it uses separable paraboloidal surrogate (SPS) technique as a foundation for reconstruction to reduce noise and cone-beam artifact, (b) it uses a view weight in the back-projection process to reduce motion artifact. To confirm the improvement of our proposed algorithm over other existing algorithm, such as Feldkamp-Davis-Kress (FDK) or SPS algorithm, we compared the motion artifact reduction, image noise reduction (standard deviation of CT number), and cone-beam artifact reduction on simulated and clinical data set. Our results demonstrate that the proposed algorithm dramatically reduces motion artifacts compared with the SPS algorithm, and decreases image noise compared with the FDK algorithm. In addition, the proposed algorithm potentially improves time resolution of iterative reconstruction. (orig.)

  8. Imaging bowel obstruction: A comparison between fast magnetic resonance imaging and helical computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Beall, D.P.; Fortman, B.J.; Lawler, B.C.; Regan, F

    2002-08-01

    AIM: To compare the accuracy of fast magnetic resonance (MR) imaging using the half-Fourier single shot turbo spin echo (HASTE) sequence with helical computed tomography (CT) in diagnosing bowel obstruction. MATERIALS AND METHODS: Prospective evaluation of 44 patients with clinical evidence of bowel obstruction was conducted using various investigations including HASTE MR and helical CT. MR was performed with a Siemens 1.5 Tesla MR Imaging System and CT was performed with one of two Siemens ARHP CT systems using helical technique. MR acquisition allowed data to be gathered in 6-10 minutes and no contrast media were administered. CT imaging consisted of consecutive helical CT through the abdomen and pelvis with oral and intravenous contrast medium used when indicated. Bowel dilation along with the presence and level of obstruction were determined. RESULTS: Twenty-eight patients had bowel obstruction confirmed at laparotomy or by radiographic assessment. Of these, 25 had small bowel obstruction and three had colonic obstructions. The obstruction was due to fibrous adhesions in nine patients, metastases or primary carcinoma in seven, Crohn's disease in four, hernias in two, and inflammation or abscess in two. Other causes of obstruction included lymphoma, intussusception and anastomotic stricture. The cause of obstruction was correctly diagnosed by CT in 71%, and by MR in 95% of cases. The sensitivity, specificity and accuracy for HASTE MR imaging was 95%, 100% and 96% respectively as compared to 71%, 71% and 71% for helical CT. CONCLUSION: Fast MR imaging using the HASTE sequence is more accurate than helical CT in diagnosing bowel obstruction. Beall, D.P. et al. (2002)

  9. Helical CT findings of gastric wall thickening by peptic ulcer : compared with gastric adenocarcinoma with ulcer

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Won Jung; Choi, Jong Chul; Seo, Keum Soo; Koo, Bon Sik; Park, Byeong Ho; Kim, Chung Ku; Lee, Ki Nam; Nam, Kyung Jin [College of Medicine, Dong A University, Pusan (Korea, Republic of)

    2000-02-01

    To compare on the basis of helical CT findings gastric wall thickening of peptic gastric ulcer with that of gastric adenocarcinoma with ulcer. Thirty-eight patients with pathologically proven gastric lesion (17 cases of peptic ulcer and 21 cases of ulcerative or ulceroinfiltrative gastric cancer (Borrman type II, III)) underwent helical CT, and the findings were retrospectively reviewed in terms of maximum abnormal wall thickness, preservation of the inner enhancing layer, the presence three discriminate layers of gastric wall, and enhancement pattern. The enhancement pattern of abnormally thick wall was compared with that of the portal phase of back muscle, and was defined as low, iso, or high. The Chi-square test and Student t test were used for statistical analysis. In cases of peptic ulcer and gastric cancer with ulceration, maximum abnormal wall thickness was 7-30 (mean, 16.1)mm, and 11-33 (mean, 21.8)mm, respectively. The inner enhancing layer was preserved in 15 of 17 patients (88.2%) and one of 21 (4.8%); three discriminate layers of gastric wall were observed in 8 of 17 patients (47.0%), and one of 21 (4.8%). The enhancement pattern was low in 12 of 17 patients (70.5%), and 3 of 21 (14.3%); iso in 4 of 17 (23.5%), and 4 of 21 (19.0%), and high in one of 17 (5.9%), and 14 of 21 (66.7%). All figures refer, respectively, to the two distinct conditions. In terms of preservation of the inner enhancing layer, three discriminate layers of gastric wall, and a low enhancement pattern, there were statistically significant differences between peptic ulcer and gastric adenocarcinoma with ulcer. Where the enhancement was high, however, the statistically significant difference between the two conditions was even greater. There was no statistically significant difference in terms of gastric wall thickness or iso-attenuation of thickened gastric. Helical CT findings of gastric wall thickening, preservation of the inner enhancing layer, and three discriminate layers of

  10. Diagnosis of deep vein thrombosis using multi-detector helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Masashi; Minamiguchi, Hiroki; Sahara, Shinya [Wakayama Medical Coll. (Japan)] [and others

    2002-11-01

    The purpose of this study was to evaluate the usefulness of multi-detector helical CT (MDHCT) with contrast medium in the diagnosis of deep vein thrombosis (DVT). The bilateral veins of the dorsal pedis in 45 patients (12 men, 33 women; average age, 64 years) under clinical suspicion of DVT were first punctured using 22-G needles. Then CT scanning from the level of the foot to the inferior vena cava was started 20 sec after the initial injection of 200 mL of dilute contrast medium (50 mL nonionic iodinated contrast medium of 300 mgI/mL and 150 mL saline) at a rate of 5 mL/sec. Two patients were excluded because of unsuccessful venous puncture. The average scanning time in 43 patients was 38.5{+-}7.9 seconds. Images of veins from the foot to the inferior vena cava were clearly demonstrated in each case. MDHCT showed DVT in 32 cases and patent deep vein in 11 cases. Simultaneous venography of the lower extremity in 18 patients clearly visualized DVT at the same level detected by contrast MDHCT. MDHCT for the diagnosis of DVT has the advantages of wider scanning rage, shorter scanning time, and finer Z-axis resolution than the other diagnostic modalities. (author)

  11. Usefulness of helical CT in the diagnosis of strangulation in small bowel obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Young Hye; Kim, Won Hong; Jeon, Yong Sun; Shin, Dong Jae; Cho, Soon Gu; Lee, Chang Keun; Choi, Sun Keun [College of Medicine, Inha Univ., Incheon (Korea, Republic of)

    2004-12-01

    We wished to evaluate the usefulness of helical CT for the diagnosis of strangulation of the dilated small bowels. The CT scans of 31 patients with small bowel obstruction from various causes were reviewed retrospectively. Thirteen of these patients were confirmed as small bowel strangulation by surgery and pathology. Fourteen patients underwent surgery, but they had no strangulation. Three patients were reduced by using a nasogastric tube and one infant with intussusception was reduced by air reduction. The following CT findings of strangulation were evaluated: reduced bowel wall enhancement by visual assessment and measuring the HU, ascites, thickening of bowel wall, abnormal mesenteric vessel location and whirlpool appearance, and mesenteric venous engorgement. For the precise evaluation of reduced bowel wall enhancement, the HUs were measured by 1 mm{sup 2} of ROI, and the differences of HUs between the well enhanced bowel and poorly enhanced bowel were compared. For the diagnosis of strangulation, measurement of HU of the bowel wall could improve the sensitivity from 69% to 100%. The specificity of both methods, by visual assessment and measurement of HU, was 94%. Ascites had a sensitivity of 69% and specificity of 44%. Thickening of bowel wall had a sensitivity of 38% and specificity of 78%. Abnormal mesenteric vessel location and whirlpool appearance had a sensitivity of 38% and specificity of 83%. Mesenteric venous engorgement had a sensitivity of 31% and specificity of 72%. Measurement of HU of the bowe wall after contrast enhancement can be a useful method in the differential diagnosis between the strangulated and non-strangulated bowels in patients with small bowel obstruction.

  12. Dynamic evaluation of pelvic floor reconstructive surgery using radiopaque meshes and three-dimensional helical CT

    Directory of Open Access Journals (Sweden)

    Paulo Palma

    2010-04-01

    Full Text Available PURPOSE: This prospective study was performed to achieve visualization of the reestablishment of anatomy after reconstructive surgery in the different pelvic compartments with non-absorbable radiopaque meshes, providing valuable anatomic information for surgeons implanting meshes. MATERIALS AND METHODS: A total of 30 female patients with stress urinary incontinence (SUI, anterior and posterior vaginal wall prolapse, or both underwent surgical repair using radiopaque meshes after written informed consent. Patients with SUI underwent five different surgeries. Patients with anterior vaginal prolapse underwent a procedure using a combined pre-pubic and transobturator mesh, and those with posterior vaginal prolapse underwent posterior slingplasty. Three-dimensional reconstruction using helical CT was performed four weeks postoperatively. RESULTS: In all cases, the mesh was clearly visualized. Transobturator slings were shown at the midurethra, and the anchoring tails perforated the obturator foramen at the safety region. Mini-slings were in the proper place, and computed angiography revealed that the anchoring system was away from the obturator vessels. In patients undergoing procedure for anterior vaginal prolapse, both pre-pubic armpit and obturator slings were clearly seen and the mesh was in the proper position, supporting the bladder base and occluding the distal part of the urogenital hiatus. Transcoccygeal sacropexy revealed indirectly a well-supported "neo rectovaginal fascia" and the anchoring tails at the level of ischial spines. CONCLUSION: Three-dimensional helical tomography images of the female pelvis using radiopaque meshes have a potential role in improving our understanding of pelvic floor reconstructive surgeries. These radiopaque meshes might be the basis of a new investigative methodology.

  13. FDK-Type Algorithms with No Backprojection Weight for Circular and Helical Scan CT

    Directory of Open Access Journals (Sweden)

    A. V. Narasimhadhan

    2012-01-01

    Full Text Available We develop two Feldkamp-type reconstruction algorithms with no backprojection weight for circular and helical trajectory with planar detector geometry. Advances in solid-state electronic detector technologies lend importance to CT systems with the equispaced linear array, the planar (flat panel detectors, and the corresponding algorithms. We derive two exact Hilbert filtered backprojection (FBP reconstruction algorithms with no backprojection weight for 2D fan-beam equispace linear array detector geometry (complement of the equi-angular curved array detector. Based on these algorithms, the Feldkamp-type algorithms with no backprojection weight for 3D reconstruction are developed using the standard heuristic extension of the divergent beam FBP algorithm. The simulation results show that the axial intensity drop in the reconstructed image using the FDK algorithms with no backprojection weight with circular trajectory is similar to that obtained by using Hu's and T-FDK, algorithms. Further, we present efficient algorithms to reduce the axial intensity drop encountered in the standard FDK reconstructions in circular cone-beam CT. The proposed algorithms consist of mainly two steps: reconstruction of the object using FDK algorithm with no backprojection weight and estimation of the missing term. The efficient algorithms are compared with the FDK algorithm, Hu's algorithm, T-FDK, and Zhu et al.'s algorithm in terms of axial intensity drop and noise. Simulation shows that the efficient algorithms give similar performance in axial intensity drop as that of Zhu et al.'s algorithm while one of the efficient algorithms outperforms Zhu et al.'s algorithm in terms of computational complexity.

  14. FDK-Type Algorithms with No Backprojection Weight for Circular and Helical Scan CT.

    Science.gov (United States)

    Narasimhadhan, A V; Rajgopal, Kasi

    2012-01-01

    We develop two Feldkamp-type reconstruction algorithms with no backprojection weight for circular and helical trajectory with planar detector geometry. Advances in solid-state electronic detector technologies lend importance to CT systems with the equispaced linear array, the planar (flat panel) detectors, and the corresponding algorithms. We derive two exact Hilbert filtered backprojection (FBP) reconstruction algorithms with no backprojection weight for 2D fan-beam equispace linear array detector geometry (complement of the equi-angular curved array detector). Based on these algorithms, the Feldkamp-type algorithms with no backprojection weight for 3D reconstruction are developed using the standard heuristic extension of the divergent beam FBP algorithm. The simulation results show that the axial intensity drop in the reconstructed image using the FDK algorithms with no backprojection weight with circular trajectory is similar to that obtained by using Hu's and T-FDK, algorithms. Further, we present efficient algorithms to reduce the axial intensity drop encountered in the standard FDK reconstructions in circular cone-beam CT. The proposed algorithms consist of mainly two steps: reconstruction of the object using FDK algorithm with no backprojection weight and estimation of the missing term. The efficient algorithms are compared with the FDK algorithm, Hu's algorithm, T-FDK, and Zhu et al.'s algorithm in terms of axial intensity drop and noise. Simulation shows that the efficient algorithms give similar performance in axial intensity drop as that of Zhu et al.'s algorithm while one of the efficient algorithms outperforms Zhu et al.'s algorithm in terms of computational complexity.

  15. Diagnosis of nutcracker syndrome of the left renal vein. Value of the corticomedullary phase of helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Igari, Hidenori [Yokohama Comprehensive Care Continuum (Japan)

    2001-05-01

    The clinical significance of the corticomedullary phase of helical CT in the diagnosis of nutcracker syndrome of the left renal vein (LRV) was evaluated. A total of 38 patients with hematuria of unknown origin (12 men and 26 women, mean age 24 years [range: 18-32 years]) were examined by helical CT of the kidneys, retrograde left renal venography, and measurement of renocaval pressure gradients. The sensitivity and specificity of the corticomedullary and nephrographic phases of helical CT for detecting the nutcracker syndrome were determined. The nutcracker syndrome was diagnosed on the basis of the renography findings combined with pressure measurements in 19 patients: 12 with LRV hypertension and collateral veins, 1 with hypertension and no collateral veins, and 6 with collateral veins and normal pressure gradients or borderline hypertension. Both the corticomedullary- and nephrographic-phase images revealed distended LRVs in 26 (68%) of the 38 patients. The LRV mean attenuation values in the corticomedullary phase (164{+-}22 Hounsfield units [H], range: 138-209 H) was significantly greater (p<0.001) than in the nephrographic phase (80{+-}14 H, range: 62-100 H). During the corticomedullary phase, opacified blood from the renal vein was mixed with unopacified blood in the IVC. In the nephrographic phase, however, the IVC was enhanced homogeneously, but only slightly. Corticomedullary-phase imaging detected collateral veins that exhibited early enhancement, indicating retrograde flow from the LRVs in 15 out of 18 patients (83% of those with collateral veins), while the nephrographic-phase imaging revealed collateral veins in 8 patients (44% of those with collateral veins). The sensitivity and specificity of the corticomedullary-phase scan for detecting the nutcracker syndrome were 79% and 100%, respectively, as opposed to 42% and 100%, respectively, for the nephrographic phase. Retrograde flow from the LRV into the collateral veins in the corticomedullary phase is

  16. Investigating the minimum scan parameters required to generate free-breathing motion artefact-free fast-helical CT.

    Science.gov (United States)

    Thomas, David H; Tan, Jun; Neylon, Jack; Dou, Tai; O'Connell, Dylan; McNitt-Gray, Michael; Lee, Percy; Lamb, James; Low, Daniel A

    2018-02-01

    A recently proposed "5DCT" protocol uses deformable registration of free-breathing fast-helical CT scans to generate a breathing motion model. In order to allow accurate registration, free-breathing images are required to be free of doubling-artefacts, which arise when tissue motion is greater than scan speed. Using a unique set of digital phantoms based on patient data and verified with a motion phantom, this work identifies the minimum scanner parameters required to successfully generate free-breathing artefact-free fast-helical scans. A motion phantom and 5 patients were imaged 25 times under free-breathing conditions in alternating directions with a 64-slice CT scanner employing a low-dose fast-helical protocol. A series of high temporal resolution (0.1 s) 5DCT scan data sets was generated in each case. A simulated CT scanner was used to "image" each free-breathing data set. Various CT scanner detector widths and rotation times were simulated, and verified using the motion phantom results. Motion-induced artefacts were quantified in patient images using structural similarity maps to determine the similarity between axial slices. Increasing amounts of motion-induced artefacts were observed with increasing rotation times >0.2 s for 16 mm detector configuration. The current generation of 16-slice CT scanners, which are present in the majority of Radiation Oncology departments, are not capable of generating free-breathing sorting artefact-free images required for 5DCT. Advances in knowledge: A recently proposed "5DCT" protocol uses deformable registration of free-breathing fast-helical CT scans to generate a breathing motion model. In order to allow accurate registration, free-breathing images are required to be free of doubling-artefacts, which arise when tissue motion is greater than scan speed. The results suggest that the current generation of 16-slice CT scanners, present in the majority of Radiation Oncology departments, are not capable of generating

  17. Imaging of Blood Flow in Cerebral Arteries with Dynamic Helical Computed Tomography Angiography (DHCTA) Using a 64-Row CT Scanner

    Energy Technology Data Exchange (ETDEWEB)

    Pekkola, J.; Kangasniemi, M. (Helsinki Medical Imaging Center, Helsinki Univ. Central Hospital, Helsinki (Finland))

    2009-08-15

    Background: Cerebral computed tomography angiography (CTA) depicts a structural image of intracranial arteries without providing much time-resolved information on blood flow dynamics. Current CT technology allows obtaining of rapidly repeated helical scans during the arterial contrast filling phase after an intravenous contrast injection. Purpose: To report our experience on dynamic CT imaging in determining the direction of contrast filling within proximal intracranial arteries of operated cerebral artery aneurysm patients. Such dynamic information can help detect vascular occlusion or severe spasm. The method is here referred to as dynamic helical CT angiography (DHCTA). Material and Methods: We retrospectively collected image and related technical data for 23 patients who underwent DHCTA and CTA during their first postoperative day after cerebral artery aneurysm surgery. For DHCTA, we had helically scanned a 4-cm tissue volume three times in succession with a 64-row CT scanner at intervals of 2.6 s during arterial contrast filling after an intravenous contrast injection. We assessed how well DHCTA succeeded in demonstrating the direction of contrast filling in the proximal intracranial arteries, evaluated clinically relevant structural information provided by DHCTA and CTA, and compared radiation doses for the two methods. Results: For 21 patients, DHCTA outlined the direction of contrast filling in proximal intracranial arteries. As to arterial spasm and residual filling of the operated aneurysm, CTA and DHCTA gave similar information. Radiation doses were higher (P<0.000001) for DHCTA than for CTA at 120 kV tube voltage. At 100 kV, the difference was smaller, but doses for DHCTA still exceeded (P<0.05) those for CTA. Conclusion: DHCTA gave dynamic information unobtainable with CTA and could prove useful in selected clinical settings

  18. Comparison of excretory phase, helical computed tomography with intravenous urography in patients with painless haematuria.

    Science.gov (United States)

    O'Malley, M E; Hahn, P F; Yoder, I C; Gazelle, G S; McGovern, F J; Mueller, P R

    2003-04-01

    To compare excretory phase, helical computed tomography (CT) with intravenous (IV) urography for evaluation of the urinary tract in patients with painless haematuria. Ninety-one out-patients had IV urography followed by helical CT limited to the urinary tract. Both IV urograms and CT images were evaluated for abnormalities of the urinary tract in a blinded, prospective manner. The clinical significance of abnormalities was scored subjectively and receiver operator characteristic curve analysis was performed. In 69 of 91 patients (76%), no cause of haematuria was identified. In 22 of 91 patients (24%), the cause of haematuria was identified as follows: transitional cell cancer of the bladder (n=15), urinary tract stones (n=3), cystitis (n=2), haemorrhagic pyelitis (n=1) and benign ureteral stricture (n=1). With IV urography, there were 15 true-positive, seven false-negative and three false-positive interpretations. With CT, there were 18 true-positive, four false-negative and two false-positive interpretations. There was no significant difference between IV and CT urography for the significance of the positive interpretations (n=0.47). Excretory phase CT urography was comparable with IV urography for evaluation of the urinary tract in patients with painless haematuria. However, the study population did not include any upper tract cancers.

  19. Comparison of excretory phase, helical computed tomography with intravenous urography in patients with painless haematuria

    Energy Technology Data Exchange (ETDEWEB)

    O' Malley, M.E.; Hahn, P.F.; Yoder, I.C.; Gazelle, G.S.; McGovern, F.J.; Mueller, P.R

    2003-04-01

    AIM: To compare excretory phase, helical computed tomography (CT) with intravenous (IV) urography for evaluation of the urinary tract in patients with painless haematuria. MATERIALS AND METHODS: Ninety-one out-patients had IV urography followed by helical CT limited to the urinary tract. Both IV urograms and CT images were evaluated for abnormalities of the urinary tract in a blinded, prospective manner. The clinical significance of abnormalities was scored subjectively and receiver operator characteristic curve analysis was performed. RESULTS: In 69 of 91 patients (76%), no cause of haematuria was identified. In 22 of 91 patients (24%), the cause of haematuria was identified as follows: transitional cell cancer of the bladder (n=15), urinary tract stones (n=3), cystitis (n=2), haemorrhagic pyelitis (n=1) and benign ureteral stricture (n=1). With IV urography, there were 15 true-positive, seven false-negative and three false-positive interpretations. With CT, there were 18 true-positive, four false-negative and two false-positive interpretations. There was no significant difference between IV and CT urography for the significance of the positive interpretations (n=0.47). CONCLUSION: Excretory phase CT urography was comparable with IV urography for evaluation of the urinary tract in patients with painless haematuria. However, the study population did not include any upper tract cancers. O'Malley M. E. et al. (2003). Clinical Radiology 58, 294-300.

  20. Lung Motion Model Validation Experiments, Free-Breathing Tissue Densitometry, and Ventilation Mapping using Fast Helical CT Imaging

    Science.gov (United States)

    Dou, Hsiang-Tai

    The uncertainties due to respiratory motion present significant challenges to accurate characterization of cancerous tissues both in terms of imaging and treatment. Currently available clinical lung imaging techniques are subject to inferior image quality and incorrect motion estimation, with consequences that can systematically impact the downstream treatment delivery and outcome. The main objective of this thesis is the development of the techniques of fast helical computed tomography (CT) imaging and deformable image registration for the radiotherapy applications in accurate breathing motion modeling, lung tissue density modeling and ventilation imaging. Fast helical CT scanning was performed on 64-slice CT scanner using the shortest available gantry rotation time and largest pitch value such that scanning of the thorax region amounts to just two seconds, which is less than typical breathing cycle in humans. The scanning was conducted under free breathing condition. Any portion of the lung anatomy undergoing such scanning protocol would be irradiated for only a quarter second, effectively removing any motion induced image artifacts. The resulting CT data were pristine volumetric images that record the lung tissue position and density in a fraction of the breathing cycle. Following our developed protocol, multiple fast helical CT scans were acquired to sample the tissue positions in different breathing states. To measure the tissue displacement, deformable image registration was performed that registers the non-reference images to the reference one. In modeling breathing motion, external breathing surrogate signal was recorded synchronously with the CT image slices. This allowed for the tissue-specific displacement to be modeled as parametrization of the recorded breathing signal using the 5D lung motion model. To assess the accuracy of the motion model in describing tissue position change, the model was used to simulate the original high-pitch helical CT scan

  1. Unusual presentation of a pancreatic insulinoma in helical CT and dynamic contrast-enhanced MR imaging: case report

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias, A.; Arias, M.; Brasa, J. [Unidad de Resonancia Magnetica (Medtec), Hospital Xeral-Cies, Vigo (Spain); Casal, M. [Unidad de Radiologia Intervencionista, Hospital Xeral-Cies, Vigo (Spain); Paramo, C. [Servicio de Endocrinologia, Hospital Xeral-Cies, Vigo (Spain); Fiano, C. [Servicio de Anatomia Patologica, Hospital Xeral-Cies, Vigo (Spain)

    2001-06-01

    Insulinomas are pancreatic neoplasms that can be radiologically characterized typically because of their tendency to present intense and early contrast enhancement with a wash-out phenomenon. In this sense, we report an unusual case of a hypovascular solid pancreatic insulinoma confirmed with surgery and pathologic analysis, in a patient with normal serum insulin levels. In the two-phase helical CT, the mass behaved as a hypodense lesion with respect to the surrounding pancreatic parenchyma during the arterial phase and as a hypointense lesion during the dynamic contrast-enhanced MR imaging. Pathologic examination demonstrated a hypercellular tumor with poor vascularization of intervening stroma which showed prominent amyloid deposits. (orig.)

  2. Helical CT in the evaluation of cranio-facial fibrous dysplasia; Scanner spirale et bilan diagnostique de dysplasie fibreuse cranio-faciale

    Energy Technology Data Exchange (ETDEWEB)

    Lupescu, I.; Georgescu, S.A. [Hopital Fundeni, Service de Radiologie, Bucarest, (Romania); Hermier, M.; Froment, J.C. [Hopital Neurologique et Neurochirurgical P. Wertheimer, 69 - Lyon (France)

    2001-02-01

    Purpose. To evaluate the role of helical CT in the evaluation of skull abnormalities seen in fibrous dysplasia. Materials and Methods. Prospective study on 6 cases with cranio-facial fibrous dysplasia (3 males and 3 females) aged 8 to 59 years old, evaluated with plain radiographs, helical CT and, in 1 case, MRI. Helical CT was performed in 3 cases on a CT Twin scan (Elscint), in 3 cases on a Somatom Plus scan (Siemens). Multiplanar reconstructions and 3-D reconstructions were done in all cases. 4 cases had a histopathological confirmation of fibrous dysplasia lesions by bone-biopsy (3 cases) or surgical biopsy (1 case). Results. The 6 cases included sclerotic form in 3 cases, cystic variety in 1 case, poly-ostosis variety in 1 case, mixed form in 1 case. Topographic localizations of fibrous dysplasia were skull base involvement in 1 case, multi-zonal skull involvement in 4 cases, maxillo-mandibulary involvement (cherubism) in 1 case. Conclusion. Helical CT is an optimal method to evaluate the skull lesions of fibrous dysplasia. The review of source images must always be done. 3-dimensional bone reconstructions are better to visualize the anterior cranial vault and skull base dysmorphy. Helical acquisition is a compromise in case by case between the dose of irradiation and the quality of source images. (authors)

  3. Prospectively ECG Gated CT pulmonary angiography versus helical ungated CT pulmonary angiography: Impact on cardiac related motion artifacts and patient radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Shuman, William P., E-mail: wshuman@u.washington.edu [Department of Radiology, 1959 NE Pacific Street, Box 357115, Seattle, WA 98195 (United States); Leipsic, Jonathon A., E-mail: JLeipsic@providencehealth.bc.ca [University of British Columbia and St. Paul' s Hospital, Department of Radiology, 1081 Burrard Street, Vancouver, BC, V6Z1Y6 (Canada); Busey, Janet M., E-mail: jbonny@u.washington.edu [Department of Radiology, 1959 NE Pacific Street, Box 357115, Seattle, WA 98195 (United States); Green, Douglas E., E-mail: dougreen@uw.edu [Department of Radiology, 1959 NE Pacific Street, Box 357115, Seattle, WA 98195 (United States); Pipavath, Sudhakar N., E-mail: snjp@u.wwashington.edu [Department of Radiology, 1959 NE Pacific Street, Box 357115, Seattle, WA 98195 (United States); Hague, Cameron J., E-mail: cjhague@interchange.ubc.ca [University of British Columbia and St. Paul' s Hospital, Department of Radiology, 1081 Burrard Street, Vancouver, BC, V6Z1Y6 (Canada); Koprowicz, Kent M., E-mail: kentk@u.washington.edu [Department of Radiology, 1959 NE Pacific Street, Box 357115, Seattle, WA 98195 (United States)

    2012-09-15

    Objective: To compare prospectively ECG gated CT pulmonary angiography (CTPA) with routine helical ungated CTPA for cardiac related motion artifacts and patient radiation dose. Subjects and methods: Twenty patients with signs and symptoms suspicious for pulmonary embolism and who had a heart rate below 85 were scanned with prospectively ECG gated CTPA. These gated exams were matched for several clinical parameters to exams from twenty similar clinical patients scanned with routine ungated helical CTPA. Three blinded independent reviewers subjectively evaluated all exams for overall pulmonary artery enhancement and for several cardiac motion related artifacts, including vessel blurring, intravascular shading, and double line. Reviewers also measured pulmonary artery intravascular density and image noise. Patient radiation dose for each technique was compared. Fourteen clinical prospectively ECG gated CTPA exams from a second institution were evaluated for the same parameters. Results: Prospectively ECG gated CTPA resulted in significantly decreased motion-related image artifact scores in lung segments adjacent to the heart compared to ungated CTPA. Measured image noise was not significantly different between the two types of CTPA exams. Effective dose was 28% less for prospectively ECG gated CTPA (4.9 mSv versus 6.8 mSv, p = 0.02). Similar results were found in the prospectively ECG gated exams from the second institution. Conclusion: Compared to routine helical ungated CTPA, prospectively ECG gated CTPA may result in less cardiac related motion artifact in lung segments adjacent to the heart and significantly less patient radiation dose.

  4. Digital Assessment of the Implantation Angle of Proximal Femoral Nail Antirotation Helical Blade Using CT Three-dimensional Reconstruction.

    Science.gov (United States)

    Luan, Feiyu; Wang, Wenbo; Liu, Ning; Zhang, Yanan; Liu, Jinyi

    2017-10-30

    To facilitate simple and safe manipulation during proximal femoral nail antirotation (PFNA) operation, we studied the range of safe implantation angle of the helical blade of the PFNA system by using a digital-based three-dimensional reconstruction model of CT images. Thirty-five healthy volunteers were recruited. Original multilayer helical CT scan data of the left femur were collected and imported into Mimics software. Anatomic features of the femur, including the safe implantation angle, anterior and posterior angle, were measured. Differences in each angle between male and female subjects were compared using Student's t test, and the determinants of each angle were analyzed by linear regression. The mean safe implantation angle was 30.09° ± 4.73°, the mean anterior angle was 15.82° ± 2.07°, and the mean posterior angle was 14.27° ± 3.19°. All the three angles were greater in males than females (P angle and the diameter of the femoral neck and head were linearly correlated with the safe implantation angle, the anterior and posterior angle, respectively. Femoral neck diameter was a significant determinant of the safe implantation angle and posterior angle, respectively. Moreover, femoral neck diameter and femoral head diameter were significant determinants of the anterior angle. The study has introduced and delineated a novel parameter, the safe implantation angle, for FPNA surgery, which may help orthopedic surgeons in deciding a safe range of PFNA operation and improve the accuracy of PFNA helical blade implantation.

  5. [The effect of the severity of congenital pectus excavatum on the cardiac morphology in children: evaluation with multislice helical CT].

    Science.gov (United States)

    Lu, Tao; Deng, Kaihong

    2013-12-01

    This paper is aimed to evaluate the CT manifestation of congenital pectus excavatum and its effect on the cardiac morphology. CT features of 34 children with pectus excavatum were retrospectively reviewed. The Haller index (HI), CT depression index (CTDI), cardiac rotation angle (CRA), pulmonary vein angle (PVA), cardiac compression index (CCI) and cardiac asymmetry index (CAI) were measured from the images on the PACS system. The relationships among these indexes were evaluated. The HI was 4.12 +/- 1.48, the CTDI was 2.39+/- 0.70, CRA was (53.52 +/- 7.68) degrees, PVA was (66.51 +/- 11.02) degrees, CCI was 2.43 +/- 0.95, and CAI was 1.55 +/- 0.56. There was statistical significance of CCI and CAI between children with severe or slight pectus excavatum. The HI and CTDI were positively related with CCI and CAI respectively, whereas there was no statistical significance of CRA and PVA between children with severe or slight pectus excavatum. There was no statistical significance of HI, CTDI, CRA, PVA, CCI and CAI among different age groups. The morphological change of the heart compressed in children with pectus excavatum can be accurately evaluated by multislice helical CT.

  6. Dosimetric comparison of Helical Tomotherapy and Gamma Knife Stereotactic Radiosurgery for single brain metastasis

    Directory of Open Access Journals (Sweden)

    Linskey Mark E

    2006-08-01

    Full Text Available Abstract Background Helical Tomotherapy (HT integrates linear accelerator and computerized tomography (CT technology to deliver IMRT. Targets are localized (i.e. outlined as gross tumor volume [GTV] and planning target volume [PTV] on the planning kVCT study while daily MVCT is used for correction of patient's set-up and assessment of inter-fraction anatomy changes. Based on dosimetric comparisons, this study aims to find dosimetric equivalency between single fraction HT and Gamma Knife® stereotactic radiosurgery (GKSRS for the treatment of single brain metastasis. Methods The targeting MRI data set from the GKSRS were used for tomotherapy planning. Five patients with single brain metastasis treated with GKSRS were re-planned in the HT planning station using the same prescribed doses. There was no expansion of the GTV to create the PTV. Sub-volumes were created within the PTV and prescribed to the maximum dose seen in the GKSRS plans to imitate the hot spot normally seen in GKSRS. The PTV objective was set as a region at risk in HT planning using the same prescribed dose to the PTV periphery as seen in the corresponding GKSRS plan. The tumor volumes ranged from 437–1840 mm3. Results Conformality indices are inconsistent between HT and GKSRS. HT generally shows larger lower isodose line volumes, has longer treatment time than GKSRS and can treat a much larger lesion than GKSRS. Both HT and GKSRS single fraction dose-volume toxicity may be prohibitive in treating single or multiple lesions depending on the number and the sizes of the lesions. Conclusion Based on the trend for larger lower dose volumes and more constricted higher dose volumes in HT as compared to GKSRS, dosimetric equivalency was not reached between HT and GKSRS.

  7. Low-dose helical computed tomography (CT) in the perioperative workup of adolescent idiopathic scoliosis

    Energy Technology Data Exchange (ETDEWEB)

    Abul-Kasim, Kasim; Overgaard, Angelica; Maly, Pavel [Malmoe University Hospital, Department of Radiology, Section of Neuroradiology, University of Lund, Malmoe (Sweden); Ohlin, Acke [Malmoe University Hospital, Department of Orthopaedic Surgery, University of Lund, Malmoe (Sweden); Gunnarsson, Mikael [Malmoe University Hospital, Department of Radiation Physics, University of Lund, Malmoe (Sweden); Sundgren, Pia C. [University of Michigan Health Systems, Department of Radiology, Division of Neuroradiology, Ann Arbor (United States)

    2009-03-15

    The study aims were to estimate the radiation dose in patients examined with low dose spine CT and to compare it with that received by patients undergoing standard CT for trauma of the same region, as well as to evaluate the impact of dose reduction on image quality. Radiation doses in 113 consecutive low dose spine CTs were compared with those in 127 CTs for trauma. The inter- and intraobserver agreement in measurements of pedicular width, and vertebral rotation, measurements of signal-to-noise ratio and assessment of hardware status were the indicators in the evaluation of image quality. The effective dose of the low dose spine CT (0.37 mSv) was 20 times lower than that of a standard CT for trauma (13.09 mSv). This dose reduction conveyed no impact on image quality. This low dose spine CT protocol allows detailed evaluation that is necessary for preoperative planning and postoperative evaluation. (orig.)

  8. A BPF-FBP tandem algorithm for image reconstruction in reverse helical cone-beam CT.

    Science.gov (United States)

    Cho, Seungryong; Xia, Dan; Pellizzari, Charles A; Pan, Xiaochuan

    2010-01-01

    Reverse helical cone-beam computed tomography (CBCT) is a scanning configuration for potential applications in image-guided radiation therapy in which an accurate anatomic image of the patient is needed for image-guidance procedures. The authors previously developed an algorithm for image reconstruction from nontruncated data of an object that is completely within the reverse helix. The purpose of this work is to develop an image reconstruction approach for reverse helical CBCT of a long object that extends out of the reverse helix and therefore constitutes data truncation. The proposed approach comprises of two reconstruction steps. In the first step, a chord-based backprojection-filtration (BPF) algorithm reconstructs a volumetric image of an object from the original cone-beam data. Because there exists a chordless region in the middle of the reverse helix, the image obtained in the first step contains an unreconstructed central-gap region. In the second step, the gap region is reconstructed by use of a Pack-Noo-formula-based filteredback-projection (FBP) algorithm from the modified cone-beam data obtained by subtracting from the original cone-beam data the reprojection of the image reconstructed in the first step. The authors have performed numerical studies to validate the proposed approach in image reconstruction from reverse helical cone-beam data. The results confirm that the proposed approach can reconstruct accurate images of a long object without suffering from data-truncation artifacts or cone-angle artifacts. They developed and validated a BPF-FBP tandem algorithm to reconstruct images of a long object from reverse helical cone-beam data. The chord-based BPF algorithm was utilized for converting the long-object problem into a short-object problem. The proposed approach is applicable to other scanning configurations such as reduced circular sinusoidal trajectories.

  9. Helical CT of the paranasal sinuses prior to bone marrow transplantation; Klinische Relevanz der NNH-CT vor Knochenmarktransplantation

    Energy Technology Data Exchange (ETDEWEB)

    Oberholzer, K. [Mainz Univ. (Germany). Klinik fuer Radiologie; Kauczor, H.U. [Mainz Univ. (Germany). Klinik fuer Radiologie; Heussel, C.P. [Mainz Univ. (Germany). Klinik fuer Radiologie; Derigs, G. [Mainz Univ. (Germany). Klinik fuer Haematologie; Thelen, M. [Mainz Univ. (Germany). Klinik fuer Radiologie

    1997-06-01

    Purpose: To investigate the clinical necessity of CT of the paranasal sinuses before bone marrow or peripheral blood stem cell transplantation. Patients and methods: 80 patients with malignant disease underwent coronal CT of the paranasal sinuses prior to transplantation to exclude sinusitis. Results: CT revealed sinusitis requesting therapy in 17/80 patients (21%). Patients with leukaemia and non-Hodgkin lymphoma were significantly more affected. Chronic sinusitis was found in two patients, mucosal swelling not requesting therapy in 22, and normal findings in 39. Conclusion: CT of the paranasal sinuses is advised in patients suffering haemoblastoses with an increased risk of infectious complications during the transplantation phase, because pathological findings can be expected in 21% of the patients. Diagnosis and therapy of an infectious focus within the paranasal sinuses is especially important prior to allogenous bone marrow transplantation. (orig.) [Deutsch] Ziel: Die Studie ueberprueft die klinische Relevanz der computertomographischen Untersuchung der Nasennebenhoehlen (NNH) bei Patienten vor geplanter Knochenmarktransplantation oder peripherer Blutstammzelltransplantation. Patienten und Methode: 80 Patienten mit maligner Grunderkrankung wurden vor Transplantation zum Abschluss einer Sinusitis mit einer koronaren Spiral-CT untersucht und retrospektiv ausgewertet. Ergebnisse: In 17 Faellen (21%) zeigten sich bei der Screeninguntersuchung pathologische Befunde, die eine Therapie vor Transplantation erforderten. Patienten mit Leukaemien und Non-Hodgkin-Lymphomen waren am haeufigsten betroffen. 24 Patienten hatten eine geringgradige, nicht therapiebeduerftige Schleimhautschwellung, 39 einen Normalbefund. Schlussfolgerung: Patienten mit Haemoblastosen und erhoehtem Risiko fuer infektioese Komplikationen waehrend der Transplantationsphase sollten eine CT der NNH erhalten, da bei 21% der Patienten mit pathologischen Befunden zu rechnen ist. Die Diagnose und

  10. Size-specific, scanner-independent organ dose estimates in contiguous axial and helical head CT examinations.

    Science.gov (United States)

    McMillan, Kyle; Bostani, Maryam; Cagnon, Chris; Zankl, Maria; Sepahdari, Ali R; McNitt-Gray, Michael

    2014-12-01

    AAPM Task Group 204 introduced size-specific dose estimates for pediatric and adult patients undergoing body CT examinations. This investigation extends that work to head CT exams by using Monte Carlo simulations to develop size-specific, scanner-independent CTDIvol-to-organ-dose conversion coefficients. Using eight patient models from the GSF family of voxelized phantoms, dose to the brain and lens of the eye was estimated using Monte Carlo simulations of contiguous axial and helical scans for 64-slice multidetector CT scanners from four major manufacturers. For each patient model and scan mode, scanner-independent CTDIvol-to-organ-dose conversion coefficients were calculated by normalizing organ dose by scanner-specific 16 cm CTDIvol values and averaging across all scanners. Head size was measured using both geometric and attenuation-based size metrics. Head perimeter and effective diameter (ED), both geometric size metrics, were measured directly from the GSF data at the first slice superior to the eyes. Because the GSF models' pixel data are provided in terms of organ identification numbers instead of CT numbers, an indirect estimate of water equivalent diameter (WED), an attenuation-based size metric, was determined based on the relationships between WED and both ED and perimeter for a sample of patient data. Correlations between CTDIvol-to-organ-dose conversion coefficients and the various patient size metrics were then explored. The analysis of the patient data revealed a best-fit linear relationship (R(2) of 0.87) between ED and WED across a wide variety of patient sizes. Using this relationship along with ED determined from the GSF data, WED was estimated for each GSF model. An exponential relationship between CTDIvol normalized organ dose and WED was observed for both contiguous axial and helical scanning. For head perimeter and ED measured directly from the GSF data, an exponential relationship between CTDIvol normalized organ dose and patient size was

  11. Helical CT diagnosis of small bowel obstruction in the acute clinical setting

    Energy Technology Data Exchange (ETDEWEB)

    Scaglione, Mariano E-mail: mscaglione@tiscalinet.it; Romano, Stefania; Pinto, Fabio; Flagiello, Ferdinando; Farina, Roberto; Acampora, Ciro; Romano, Luigia

    2004-04-01

    Definite confirmation or exclusion closed loop obstruction (CLO) is one of the most difficult tasks the radiologist has to face in the clinical practice. Aim of this retrospective work was to study the value of spiral computed tomography (CT) in the diagnosis of closed loop obstruction complicated by intestinal ischemia. The state of the art CT signs of closed loop obstruction were taken into consideration. Serrated beaks with poor or no contrast enhancement of the bowel walls, ascites or engorgement of the mesenteric vasculature allowed the CT diagnosis of CLO complicated by ischaemia. U or C-sharped of dilated loops, radial distribution of the mesenteric vessels, beaks and whirls suggested CLO, but did not help differentiate CLO from strangulation. CLO is a dynamic entity which may regress or need laparotomy depending on the time and degree of rotation of the incarcerated loops. CT is a reliable imaging modality able to differentiate CLO from strangulation, which is rarely simple and obvious. Detection of ischemic changes in the bowel walls and/or attached mesentery on CT scans imply strangulation highlighting the need for laparotomy; if only signs of CLO are detected, the existence and/or development of strangulation cannot be predicted.

  12. Randomized prospective comparison of non-contrast enhanced helical computed tomography and intravenous urography in the diagnosis of acute ureteric colic.

    Science.gov (United States)

    Homer, J A; Davies-Payne, D L; Peddinti, B S

    2001-08-01

    Non-contrast enhanced helical CT has become an accepted technique for evaluating acute ureteric colic. The results of a randomized prospective comparison of the accuracy, cost and radiation dose of CT and intravenous urography (IVU) are presented. All patients presenting to the Emergency Department with symptoms and signs suggestive of ureteric colic over a 16-month period (n = 242) were randomized to CT or IVU. Follow up was obtained for 228 patients (94%), with 14 patients (6%) lost to follow up. One hundred and twenty-three patients (54%) underwent CT and 105 (46%) had an IVU. At follow up the sensitivity and specificity of CT were each 100%, while those of IVU were 99% and 100%, respectively. Computed tomography demonstrated seven of 26 (27%) potential alternative diagnoses, whereas IVU suggested one of 23 (4%). Estimates of the average effective dose were calculated for CT (4.95 mSv) and IVU (1.48 mSv, 95% confidence interval (CI) 0.7-2.27). Radiation dose and intravenous contrast material safety are discussed and the relative costs are considered. Computed tomography is as accurate as IVU in the diagnosis of acute ureteric colic. It confers certain major diagnostic benefits, and is a fast, well-tolerated technique. Its accompanying higher effective radiation dose is recognized.

  13. Radiation dose and cancer risk estimates in helical CT for pulmonary tuberculosis infections

    Science.gov (United States)

    Adeleye, Bamise; Chetty, Naven

    2017-12-01

    The preference for computed tomography (CT) for the clinical assessment of pulmonary tuberculosis (PTB) infections has increased the concern about the potential risk of cancer in exposed patients. In this study, we investigated the correlation between cancer risk and radiation doses from different CT scanners, assuming an equivalent scan protocol. Radiation doses from three 16-slice units were estimated using the CT-Expo dosimetry software version 2.4 and standard CT scan protocol for patients with suspected PTB infections. The lifetime risk of cancer for each scanner was determined using the methodology outlined in the BEIR VII report. Organ doses were significantly different (P < 0.05) between the scanners. The calculated effective dose for scanner H2 is 34% and 37% higher than scanners H3 and H1 respectively. A high and statistically significant correlation was observed between estimated lifetime cancer risk for both male (r2 = 0.943, P < 0.05) and female patients (r2 = 0.989, P < 0.05). The risk variation between the scanners was slightly higher than 2% for all ages but was much smaller for specific ages for male and female patients (0.2% and 0.7%, respectively). These variations provide an indication that the use of a scanner optimizing protocol is imperative.

  14. Radiation dose and cancer risk estimates in helical CT for pulmonary tuberculosis infections

    Directory of Open Access Journals (Sweden)

    Adeleye Bamise

    2017-12-01

    Full Text Available The preference for computed tomography (CT for the clinical assessment of pulmonary tuberculosis (PTB infections has increased the concern about the potential risk of cancer in exposed patients. In this study, we investigated the correlation between cancer risk and radiation doses from different CT scanners, assuming an equivalent scan protocol. Radiation doses from three 16-slice units were estimated using the CT-Expo dosimetry software version 2.4 and standard CT scan protocol for patients with suspected PTB infections. The lifetime risk of cancer for each scanner was determined using the methodology outlined in the BEIR VII report. Organ doses were significantly different (P < 0.05 between the scanners. The calculated effective dose for scanner H2 is 34% and 37% higher than scanners H3 and H1 respectively. A high and statistically significant correlation was observed between estimated lifetime cancer risk for both male (r2 = 0.943, P < 0.05 and female patients (r2 = 0.989, P < 0.05. The risk variation between the scanners was slightly higher than 2% for all ages but was much smaller for specific ages for male and female patients (0.2% and 0.7%, respectively. These variations provide an indication that the use of a scanner optimizing protocol is imperative.

  15. Computing the central path of colon lumen in helical CT images

    Science.gov (United States)

    Ge, Yaorong; Stelts, David R.; Zha, Xianliang; Wang, Jie; Vining, David J.

    1998-06-01

    We present an efficient algorithm for calculating the central path of a computer-generated colon model created from helical computed tomography image data. The central path is an essential aid for navigating through complex anatomy such as the colon. Our algorithm involves three steps. In the first step, we generate a 3D skeleton of the binary colon volume using a fast topological thinning algorithm. In the second step, we employ a graph search algorithm to remove extra loops and branches. These loops and branches are caused by holes in the object which are artifacts produced during image segmentation. In the final step, we compute a smooth representation of the central path by approximating the skeleton with cubic B-splines. This final step is necessary because the skeleton contains many abrupt changes in direction due to the discrete nature of image data. The user supplies two endpoints for the central path; otherwise, the algorithm is fully automated. Experimental results demonstrate that the algorithm is not only efficient but also robust. Use of this method in virtual endoscopy systems should have widespread clinical implications.

  16. Follow-up after stent insertion in the tracheobronchial tree: role of helical computed tomography in comparison with fiberoptic bronchoscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ferretti, G.R.; Kocier, M.; Calaque, O.; Coulomb, M. [Service Central de Radiologie et Imagerie Medicale, INSERM EMI 9924, CHU, BP 217, 38043, Grenoble Cedex 9 (France); Arbib, F.; Pison, C. [Departement de Medecine Aigue Specialisee (DMAS), CHU Grenoble, CHU, BP 217, 38043, Grenoble Cedex 9 (France); Righini, C. [Service d' Oto Rhino Laryngologie, CHU Grenoble, BP 217, 38043, Grenoble Cedex 9 (France)

    2003-05-01

    The aim of this study was to compare helical CT with fiberoptic bronchoscopy findings to appraise the medium-term results of proximal-airways stenting. Twenty-five patients with 28 endobronchial metallic stents inserted for local advanced malignancy (n=13) or benign diseases (n=12) underwent follow-up CT from 3 days to 50 months (mean 8 months). All studies were obtained using helical CT with subsequent multiplanar reformation and three-dimensional reconstruction including virtual bronchoscopy. The location, shape, and patency of stents and adjacent airway were assessed. The results of CT were compared with the results of fiberoptic bronchoscopy obtained with a mean delay of 2.5 days (SD 9 days) after CT scan. Twelve stents (43%) remained in their original position, patent and without deformity. Sixteen stents were associated with local complications: migration (n=6); external compression with persistent stenosis (n=4); local recurrence of malignancy (n=4); fracture (n=1); and non-congruence between the airway and the stent (n=1). The CT demonstrated all the significant abnormalities demonstrated at fiberoptic bronchoscopy except two moderate stenoses (20%) related to granulomata at the origin of the stent. Ten of 14 stents inserted for benign conditions were without complications as compared with 2 of 14 in malignant conditions (p=0.008). Computed tomography is an accurate noninvasive method for evaluating endobronchial stents. The CT is a useful technique for follow-up of patients who have undergone endobronchial stenting. (orig.)

  17. Accuracy of intraoral radiography, multidetector helical CT, and limited cone-beam CT for the detection of horizontal tooth root fracture.

    Science.gov (United States)

    Iikubo, Masahiro; Kobayashi, Kaoru; Mishima, Akira; Shimoda, Shinji; Daimaruya, Takayoshi; Igarashi, Chinami; Imanaka, Masahiro; Yuasa, Masao; Sakamoto, Maya; Sasano, Takashi

    2009-11-01

    The accuracies of intraoral radiography (IOR), multidetector helical computerized tomography (MDHCT) at slice thicknesses 0.63 mm and 1.25 mm, and limited cone-beam computerized tomography (LCBCT) were compared for detection of horizontal tooth root fracture. In 7 beagle dogs, 28 maxillary anterior teeth were used, of which 13 had artificially induced horizontal root fracture. The specimens were examined by the above-mentioned 4 modalities. Diagnosis of root fracture was based on direct visualization of radiolucent line in each image by 6 radiologists. Sensitivity, negative predictive value, and diagnostic accuracy (true positives + true negatives) for detecting fracture lines in LCBCT (0.96 +/- 0.04, 0.97 +/- 0.03, 0.93 +/- 0.04, respectively) were significantly higher than MDHCT at 0.63 mm (0.76 +/- 0.09, 0.8 +/- 0.05, 0.8 +/- 0.05, respectively), MDHCT at 1.25 mm (0.49 +/- 0.09, 0.66 +/- 0.04, 0.69 +/- 0.05, respectively), and IOR (0.51 +/- 0.18, 0.67 +/- 0.08, 0.69 +/- 0.08, respectively). Specificity and positive predictive value showed no significant intermethod difference among the 4 modalities. Limited cone-beam CT is more useful than the other 3 radiographic modalities for diagnostic imaging of horizontal tooth root fracture.

  18. Coronary artery calcification detected by a mobile helical CT unit in a mass screening. The frequency and relationship to coronary risk factors and coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Itani, Yasutaka; Watanabe, Shigeru; Masuda, Yoshiaki [Chiba Univ. (Japan). School of Medicine; Hanamura, Kazuhisa; Asakura, Kazuhiro; Sone, Shusuke; Sunami, Yuko; Shimura, Akimitsu; Miyamoto, Tadaaki

    2001-06-01

    A strong relationship is known to exist between coronary artery disease (CAD) and coronary artery calcification (CAC) detected by CT. In this study, we investigated the frequency of CAC and the relationship between coronary risk factors, CAD and CAC in a mass screening using a mobile helical CT unit. The total number of participants was 10008 people undergoing a medical examination for lung cancer and tuberculosis using a mobile helical CT unit. We measured the CT density of the coronary artery to detect CAC. The CT density threshold for determining CAC was above +110HU. The frequency of CAC was 16.0% in the overall patient population and significantly higher in males than in females (20.6% vs 10.7%). Frequency increased with age in both genders. Hypertension and diabetes mellitus were significantly related to CAC. Smoking showed a correlation with CAC only in males. A significant relationship was observed between CAD and CAC in males. In particular, the relationship between them was strongest in males under 60 years of age. Furthermore, the odds ratio of CAC in predicting CAD increased with increasing risk factors in both genders. (author)

  19. CT imaging before transcatheter aortic valve implantation (TAVI) using variable helical pitch scanning and its diagnostic performance for coronary artery disease.

    Science.gov (United States)

    Matsumoto, Shunsuke; Yamada, Yoshitake; Hashimoto, Masahiro; Okamura, Teppei; Yamada, Minoru; Yashima, Fumiaki; Hayashida, Kentaro; Fukuda, Keiichi; Jinzaki, Masahiro

    2017-05-01

    To evaluate the effectiveness of CT before TAVI using variable helical pitch (VHP) scanning and its diagnostic performance for coronary artery disease (CAD). Sixty patients (84.4 ± 4.6 years) scheduled for TAVI underwent CT using VHP scanning with the contrast material (CM) volume calculated as scanning time × weight [kg] × 0.06 mL. Retrospective electrocardiography (ECG)-gated scanning was utilized to examine the thorax, and non-ECG-gated scanning of the abdomen immediately followed. We analyzed CT attenuation values of the coronary arteries, aorta, iliac and femoral arteries. The coronary CT angiography images were evaluated for the presence of stenosis (≥50 %); invasive coronary angiography served as a reference standard. The average attenuations of all of the arteries were greater than 400 HU. We could evaluate the peripheral access vessels and dimensions of the ascending aorta, aortic root, and aortic annulus in all patients. The average volume of CM was 38.7 ± 8.5 mL. On per-patient and vessel analysis, CT showed 91.7 % and 89.5 % sensitivity, and 91.3 % and 97.4 % negative predictive value (NPV). CT using VHP scanning with an average CM volume of 38.7 mL is useful before TAVI and had a high sensitivity and NPV in excluding obstructive CAD. • TAVI-planning CT using variable helical pitch (VHP) scanning is useful. • The average volume of contrast material was 38.7 ± 8.5 mL. • The average attenuations of all the arteries were >400 HU. • This CT had a high sensitivity and NPV for excluding obstructive CAD.

  20. Unenhanced helical CT following excretory urography in the diagnosis of upper urinary tract disease: a little more cost, a lot more value.

    Science.gov (United States)

    Hu, Hong; Hu, Xiao-Yun; Fang, Xiang-Ming; Chen, Hong-Wei; Yao, Xia-Juan

    2010-04-01

    The objective of the study is to evaluate unenhanced CT following intravenous urography (IVU) for the detection of upper urinary tract (UUT) abnormalities, when IVU fails to provide the qualitative diagnosis. Helical CT scan was performed on patients with suspected disorders of UUT, after the completion of IVU for further diagnoses. In total, 124 cases of definite diagnosis and 71 cases of uncertain diagnosis via IVU were collected from 195 patients with suspected UUT disorders. Among the 71 uncertain cases, 65 patients were consent to undergo immediate or delayed CT scan. CT data were transferred to the workstation for postprocessing. Of all the 65 cases, the major CT diagnoses were the following: stone disease (n = 41), urinary tract infections (n = 4), UUT tumors (n = 7), neighboring invasion or metastasis (n = 2), congenital anomalies (n = 2), and compressed stenosis (n = 6). Among all the results, 62 cases were confirmed by surgery, pathology or clinical follow-up, while three cases (4.6%) left were still uncertain. The diagnose accordance rate of IVU + CT achieved to 95.4%. There was significant difference between IVU and IVU + CT in the determinate diagnosis of UUT diseases (chi (2) = 30.4, P < 0.05). In conclusion, IVU + CT provides more valuable information for the localization and qualitative diagnosis of UUT abnormalities. It is recommended as a cost-effective and time-saving complemental means for IVU.

  1. Helical CT of traumatic injuries of the thoracic aorta; Applicazioni della Tomografia Computerizzata spirale nello studio delle lesioni traumatiche dell'aorta toracica

    Energy Technology Data Exchange (ETDEWEB)

    Mengozzi, E.; Burzi, M.; Miceli, M.; Lipparini, M.; Sartoni Galloni, S. [Ospedale Maggiore, Azienda Unita' Sanitaria Locale, Bologna (Italy). Unita' Operativa di Radiologia I, Dipt. di Diagnostica per Immagini

    2000-09-01

    Acute thoracic aortic injuries account for up to 10-20% of fatalities in high-speed deceleration road accidents and have an estimated immediate fatality rate of 80-90%. Untreated survivors to acute trauma (10-20%) have a dismal prognosis: 30% of them die within 6 hours, 40-50% die within 24 hours, and 90% within 4 months. It was investigated the diagnostic accuracy of Helical Computed Tomography (Helical CT) in acute traumatic injuries of the thoracic aorta, and the role of this technique in the diagnostic management of trauma patients with a strong suspicion of aortic rupture. It was compared retrospectively the chest Helical CT findings of 256 trauma patients examined June 1995 through August 1999. Chest Helical CT examinations were performed according to trauma score, to associated traumatic lesions and to plain chest radiographic findings. All the examinations were performed with no intravenous contrast agent administration and the pitch 2 technique. After a previous baseline study, contrast-enhanced scans were acquired with pitch 1 in 87 patients. Helical CT showed aortic lesions in 9 of 256 patients examined. In all the 9 cases it was found a mediastinal hematoma and all of them had positive plain chest radiographic findings of mediastinal enlargement. Moreover, in 6 cases aortic knob blurring was also evident on plain chest film and in 5 cases depressed left mainstem bronchus and trachea deviation rightwards were observed. All aortic lesions were identified on axial scans and located at the isthmus of level. Aortic rupture was always depicted as pseudo diverticulum of the proximal descending tract and intimal flap. It was also found that periaortic hematoma in 6 cases and intramural hematoma in 1 case. There were non false positive results in the series: 7 patients with Helical CT diagnosis of aortic rupture were submitted to conventional aortography that confirmed both type and extension of the lesions as detected by Helical CT, and all findings were

  2. Inter laboratory comparison of industrial CT scanners

    DEFF Research Database (Denmark)

    Angel, Jais Andreas Breusch; Cantatore, Angela; De Chiffre, Leonardo

    2012-01-01

    In this report results from an intercomparison of industrial CT scanners are presented. Three audit items, similar to common industrial parts, were selected for circulation: a single polymer part with complex geometry (Item 1), a simple geometry part made of two polymers (Item 2) and a miniature ...

  3. Scan time and patient dose for thoracic imaging in neonates and small children using axial volumetric 320-detector row CT compared to helical 64-, 32-, and 16- detector row CT acquisitions

    Energy Technology Data Exchange (ETDEWEB)

    Kroft, Lucia J.M.; Roelofs, Joost J.H.; Geleijns, Jacob [Leiden University Medical Center, Department of Radiology, Leiden (Netherlands)

    2010-03-15

    Recently a 320-detector-row CT (MDCT) scanner has become available that allows axial volumetric scanning of a 16-cm-long range (50 cm field of view) in a single 0.35-s rotation. For imaging neonates and small children, volume scanning is potentially of great advantage as the entire scan range can be acquired in 0.35 s, which can reduce motion artefacts and may reduce the need for sedation in clinical CT imaging. Also, because there is no over-ranging associated with axial volumetric scanning, this may reduce patient radiation dose. To evaluate, by means of a phantom study, scan time and patient dose for thoracic imaging in neonates and small children by using axial cone-beam and helical fan-beam MDCT acquisitions. Paediatric imaging protocols were assessed for a 320-MDCT volumetric scanner (Aquilion ONE, Toshiba, Otawara, Japan). The 320-MDCT scanner allows for cone-beam acquisitions with coverage up to 160 mm, but it also allows for helical fan-beam acquisitions in 64-, 32-, or 16-MDCT modes. The acquisition configurations that were evaluated were 320 x 0.5 mm, 240 x 0.5 mm, and 160 x 0.5 mm for axial volumetric scanning, and 64 x 0.5 mm, 32 x 0.5 mm, and 16 x 0.5 mm for helical scanning. Dose assessment was performed for clinically relevant paediatric angiographic or chest/mediastinum acquisition protocols with tube voltages of 80 or 100 kVp and tube currents between 40 and 80 mA. Scan time was 0.35 s for 320-MDCT acquisitions, scan times varied between 1.9 s and 8.3 s for helical acquisitions. Dose savings varying between 18% and 40% were achieved with axial volumetric scanning as compared to helical scanning (for 320- versus 64-MDCT at 160 mm and 80 kVp, and for 320- versus 16-MDCT at 80 mm and 100 kVp, respectively). Statistically significant reduction in radiation dose was found for axial 320-MDCT volumetric scanning compared to helical 64-, 32-, and 16-MDCT scanning. Axial thoracic CT of neonates and small children with volumetric 320-MDCT can be performed

  4. CT imaging before transcatheter aortic valve implantation (TAVI) using variable helical pitch scanning and its diagnostic performance for coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Shunsuke; Yamada, Yoshitake; Hashimoto, Masahiro; Okamura, Teppei; Jinzaki, Masahiro [Keio University School of Medicine, Department of Diagnostic Radiology, Shinanomachi, Shinjuku-ku, Tokyo (Japan); Yamada, Minoru [Keio University School of Medicine, Research Park, Tokyo (Japan); Yashima, Fumiaki; Hayashida, Kentaro; Fukuda, Keiichi [Keio University School of Medicine, Department of Cardiology, Tokyo (Japan)

    2017-05-15

    To evaluate the effectiveness of CT before TAVI using variable helical pitch (VHP) scanning and its diagnostic performance for coronary artery disease (CAD). Sixty patients (84.4 ± 4.6 years) scheduled for TAVI underwent CT using VHP scanning with the contrast material (CM) volume calculated as scanning time x weight [kg] x 0.06 mL. Retrospective electrocardiography (ECG)-gated scanning was utilized to examine the thorax, and non-ECG-gated scanning of the abdomen immediately followed. We analyzed CT attenuation values of the coronary arteries, aorta, iliac and femoral arteries. The coronary CT angiography images were evaluated for the presence of stenosis (≥50 %); invasive coronary angiography served as a reference standard. The average attenuations of all of the arteries were greater than 400 HU. We could evaluate the peripheral access vessels and dimensions of the ascending aorta, aortic root, and aortic annulus in all patients. The average volume of CM was 38.7 ± 8.5 mL. On per-patient and vessel analysis, CT showed 91.7 % and 89.5 % sensitivity, and 91.3 % and 97.4 % negative predictive value (NPV). CT using VHP scanning with an average CM volume of 38.7 mL is useful before TAVI and had a high sensitivity and NPV in excluding obstructive CAD. (orig.)

  5. MAG3-F0 scintigraphy in decision making for emergency intervention in renal colic after helical CT positive for a urolith.

    Science.gov (United States)

    Sfakianakis, G N; Cohen, D J; Braunstein, R H; Leveillee, R J; Lerner, I; Bird, V G; Sfakianakis, E; Georgiou, M F; Block, N L; Lynne, C M

    2000-11-01

    Patients with renal colic are evaluated with clinical, laboratory, and imaging methods for stratification for emergency decompression, medical treatment, or discharge and follow up. The current standard practice is heavily based on unenhanced helical CT for detecting uroliths. However, the presence of a urolith does not necessarily mean that the kidney is obstructed and requires emergency decompression. In this study, technetium-mercaptoacetyltriglycine (MAG3) diuretic scintirenography was used to detect obstruction in patients with renal colic. The contribution of this test to patient management after positive findings from helical CT was also studied. Diagnostic criteria were established on the basis of previous experience with 60 patients who had renal colic and had undergone radiography of the kidneys, ureters, and urinary bladder (KUB) and diuretic Tc-MAG3 scintirenography and were followed up to correlate scintigraphic findings with clinical outcome. Subsequently, 80 patients with renal colic underwent scintigraphy within 12 h of presentation in the emergency room, after abdominal helical CT showed findings positive for calculus and suggestive of obstruction. After therapeutic oral or intravenous hydration and analgesics, diuretic dynamic renal scintigraphy (flow, function, delayed imaging) was performed after intravenous injections of 10 mCi (370 MBq) 99mTc-MAG3 and 40 mg furosemide (at zero time, or F0). Results were available soon after completion of the study and were considered in patient management. Four characteristic patterns of scintirenography, essential in patient stratification and treatment, had been standardized and were used for interpretation of the studies: the unobstructed kidney; the partially obstructed kidney, proximally or distally obstructed, with mild to severe obstruction and impairment of function; the totally obstructed kidney, with arrested renal function; and the unobstructed but dysfunctioning kidney after decompression, or

  6. Optimisation of Double Pipe Helical Tube Heat Exchanger and its Comparison with Straight Double Tube Heat Exchanger

    Science.gov (United States)

    Kareem, Rashid

    2017-10-01

    Optimization of double pipe helical coil heat exchanger with various optimizing parameters and its comparison with double pipe straight tube are the prime objectives of this paper. Numerical studies were performed with the aid of a commercial computational fluid dynamics package ANSYS FLUENT 14. In this paper the double pipe helical coil is analysed under turbulent flow conditions for optimum heat exchanger properties. The parameters used for optimization are cross-sectional shape and taper angles. Optimization analysis is being carried out for finding best cross sectional shape of heat exchanger coils by using rectangular, square, triangular and circular cross-sections. The tapered double pipe helical coil is then analysed for best heat transfer and pressure drop characteristics by varying the angle of taper. Finally, an optimum coil on the basis of all the analysis is selected. This optimized double pipe helical coil is compared with double pipe straight tube of equivalent cross-sectional area and length as that of unwounded length of double pipe helical coil.

  7. InteraqCT Comparison on Assemblies - Reference Measurements

    DEFF Research Database (Denmark)

    Stolfi, Alessandro; De Chiffre, Leonardo

    2016-01-01

    The InteraqCT comparison on assemblies is as an activity within the Marie Curie ESR Project INTERAQCT - International Network for the Training of Early stage Researchers on Advanced Quality control by Computed Tomography funded by the European Commission's 7th Framework Programme FP7-PEOPLE - Under...

  8. InteraqCT Comparison on Assemblies - Technical Protocol

    DEFF Research Database (Denmark)

    Stolfi, Alessandro; De Chiffre, Leonardo

    2016-01-01

    The InteraqCT comparison on assemblies is as an activity within the Marie Curie ESR Project INTERAQCT - International Network for the Training of Early stage Researchers on Advanced Quality control by Computed Tomography funded by the European Commission's 7th Framework Programme FP7-PEOPLE - Under...

  9. Colorectal carcinoma evaluated by incremental dynamic CT; Comparison of CT density, histology, and tumor size

    Energy Technology Data Exchange (ETDEWEB)

    Furukawa, Hiroyoshi; Hara, Tsuyoshi; Taniguchi, Tetsushi (Shimizu Kosei Hospital, Shizuoka (Japan))

    1992-06-01

    Evaluation of incremental dynamic CT scan and histologic findings were compared in order to clarify the cause of the differences in colorectal carcinoma as observed on CT after administration of contrast medium. In 48 cases demonstrated on postcontrast dynamic CT scan, the CT density of the tumor was homogeneous (Type 1) in 26 (54.2%) cases and heterogeneous (Type 2) in 22 (45.8%) cases. Well differentiated adenocarcinoma was seen as Type 1 in 11 of 13 (84.6%) cases while moderately differentiated adenocarcinoma was of Type 1 in 15 of 29 (51.7%) cases. Poorly differentiated and mucinous adenocarcinoma were detected as Type 2 in all cases. A comparison of CT types and tumor size showed that as tumor size increased, the number of Type 1 cases decreased while Type 2 cases increased. Histologically, high density areas consisted mainly of well-developed tubular, branching glands of adenocarcinoma, while low density areas were composed of fibrous or mucinous stroma or necrosis. Dynamic CT scans for colorectal cancer are useful not only for preoperative staging but also for tissue characterization. (author).

  10. Exploration of cervical carotid stenosis using helical CT angiography. A prospective trial on the detection of candidates for surgery in the Gujo area, Gifu

    Energy Technology Data Exchange (ETDEWEB)

    Yamakawa, Hiroyasu; Sumi, Yasuhiko [Sumi Hospital, Gifu (Japan); Kaku, Yasuhiko; Sakai, Noboru; Yamada, Hiromu

    1995-04-01

    To detect cervical carotid stenosis as a candidate for carotid endarterectomy (CEA), the authors attempted a prospective trial by exploring stenosis for one year in a rural district with a population of 20,000, employing helical CT angiography which apparently displayed three-dimensional reconstructed images of the carotid bifurcation. Thirty-three patients, 24 males and 9 females, with a mean age of 71.8 years, suffering from TIA, RIND or stroke were investigated for their carotid systems. The clinical symptoms of the patients were briefly as follows: motor weakness in 30 cases, dysarthria in 8 cases and aphasia in 4 cases; and 6 of 22 (27%) stroke cases had previously suffered an episode of TIA. The risk factors of the whole group of patients were hypertension in 13 cases, diabetes mellitus in 6, heart disease in 17, and hypercholesteremia in 4. Helical CT angiography was performed in 11 cases of TIA, 2 cases of RIND, and 16 cases of stroke. Only 3 cases of the TIA group and 3 cases of the stroke group were found to have extracranial carotid stenosis of more than 50%, which subsequently required conventional angiography. For the detection of stenosis, CT angiography was beneficial as well as conventional angiography. Finally, CEA was performed in 2 of 3 cases with severe carotid stonosis in the TIA group, while such cases in the stroke group were only observed. The above results meant that the occurrence of extracranial carotid stenosis was 6 out of 6,589 elderly inhabitants (over 60 years old), although the possible detection rate of candidates for CEA was 2 out of 20,000 population per year. (author).

  11. Comparison of cone beam CT and conventional CT in absorbed and effective dose

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Yeon; Han, Jin Woo; Park, In Woo [Department of Oral and Maxillofacial Radiology, College of Dentistry, Kangnung National University and Reseach Institute of Oral Science, Gangneung (Korea, Republic of)

    2008-03-15

    This study provides comparative measurements of absorbed and effective doses for newly developed cone beam computed tomography (CT) in comparison with these doses for conventional CT. Thermoluminescent dosimeter rods (TLD rod: GR-200, Thermo Fisher Scientific Inc., Waltham, MA, USA) were placed at 25 sites throughout the layers of Male ART Head and Neck Phantom (Radiology Support Devices Inc., Long Beach, USA) for dosimetry. Implagraphy, DCT Pro (Vatech Co., Hwasung, Korea) units, SCT-6800TXL (Shimadzu Corp., Kyoto, Japan), and Cranex 3+ (Soredex Orion Corp., Helsinki, Finland) were used for radiation exposures. Absorption doses were measured with Harshaw 3500TLD reader (Thermo Fisher Scientific Inc., Waltham, MA, USA). Radiation weighted doses and effective doses were measured and calculated by 2005 ICRP tissue weighting factors. Absorbed doses in Rt. submandibular gland were 110.57 mGy for SCT 6800TXL (Implant), 24.56 mGy for SCT 6800TXL (3D), 22.39 mGy for Implagraphy3, 7.19 mGy for DCT Pro, 5.96 mGy for Implagraphy1, 0.70 mGy for Cranex 3+. Effective doses (E2005draft) were 2.551 mSv for SCT 6800TXL (Implant), 1.272 mSv for SCT 6800TXL (3D), 0.598 mSv for Implagraphy3, 0.428 mSv for DCT Pro and 0.146 mSv for Implagraphy1. These are 108.6, 54.1, 25.5, 18.2 and 6.2 times greater than panoramic examination (Cranex 3+) doses (0.023 mSv). Cone beam CT machines recently developed in Korea, showed lower effective doses than conventional CT. Cone beam CT provides a lower dose and cost motive to conventional CT, promising to revolutionize the practice of oral and maxillofacial radiology.

  12. A Theoretical-Experimental Comparison of an Improved Ammonia-Water Bubble Absorber by Means of a Helical Static Mixer

    Directory of Open Access Journals (Sweden)

    Jesús Cerezo

    2017-12-01

    Full Text Available The heat transfer in double pipe heat exchangers is very poor. This complicates its application in absorption cooling systems, however, the implementation of simple passive techniques should help to increase the heat and mass transfer mainly in the absorber. This paper carried out a simulation and its experimental comparison of a NH3-H2O bubble absorption process using a double tube heat exchanger with a helical screw static mixer in both central and annular sides. The experimental results showed that the absorption heat load per area is 31.61% higher with the helical screw mixer than the smooth tube. The theoretical and experimental comparison showed that the absorption heat load difference values were 28.0 and 21.9% for smooth tube and the helical mixer, respectively. These difference values were caused by the calculation of the log mean temperature difference in equilibrium conditions to avoid the overlap of solution temperatures. Therefore, the theoretical and experimental results should be improved when the absorption heat is included in the heat transfer equation or avoiding the operation condition when output is lower than input solution temperature.

  13. Evaluation of right ventricular performance in patients with acute pulmonary embolism by helical CT; Beurteilung der Rechtsherzbelastung in der Spiral-CT bei Patienten mit akuter Lungenembolie

    Energy Technology Data Exchange (ETDEWEB)

    Wintersperger, B.J.; Staebler, A.; Seemann, M.; Holzknecht, N.; Helmberger, T.; Reiser, M.F. [Muenchen Univ. (Germany). Inst. fuer Radiologische Diagnostik; Fink, U. [Klinikum Villingen-Schwenningen (Germany). Inst. fuer Radiologie

    1999-06-01

    Purpose: Purpose of this study was to evaluate whether spiral-CT allows judgment of right ventricular failure in patients with acute pulmonary embolism. Materials and Methods: 61 patients underwent spiral-CT due to suspicion of acute pulmonary embolism. Patients with pulmonary embolism were divided into subpopulations according to the severity of pulmonary embolism in the CT scan. Cardiac measurements were performed on axial spiral-CT images and compared to those of patients without suspicion of pulmonary embolism or cardiac diseases. Results: In 30 patients spiral-CT revealed acute pulmonary embolism. Significant differences in cardiac measurements in patients with severe and less severe pulmonary embolism were found on comparing the following dimensions: left ventricular width (p=0.0003), left (p=0.008) and right (p=0.009) ventricular cross-sectional area, proportion of right to left ventricular width (p=0.0003) and proportion of right to left ventricular cross-sectional area (p=0.0001). The proportion of the cross-sectional areas (r=0.65) and the proportion of the width (r=0.60) of both ventricles correlated well with the severity of central pulmonary embolism. Conclusion: Besides reliable assessment of pulmonary embolism spiral-CT allows the evaluation of cardiac dimensions for judgment of right ventricular failure. (orig.) [Deutsch] Ziel: Es wurde untersucht, ob bei Patienten mit akuter Lungenembolie durch die Spiral-CT kardiale Messparameter zur Abschaetzung der rechtsventrikulaeren Belastung bestimmt werden koennen. Material und Methoden: 61 Patienten mit Verdacht auf akute Lungenembolie wurden mit Spiral-CT untersucht. Bei Patienten mit Lungenembolie in der Spiral-CT erfolgte die Evaluierung kardialer Messparameter (Laenge, Breite, Flaeche) beider Ventrikel anhand axialer Spiral-CT Bilddaten. Patienten wurden anhand der Spiral-CT in Gruppen verschiedenen Embolieausmasses eingeteilt und mit einem Normalkollektiv verglichen. Ergebnisse: Bei 30 Patienten

  14. InteraqCT Comparison on Assemblies - Final Report

    DEFF Research Database (Denmark)

    Stolfi, Alessandro; De Chiffre, Leonardo

    2016-01-01

    are in accordance with the reference values. L2, L3, and T, which are bidirectional measurands, show lower agreement than L1 and L4, which are unidirectional lengths. The majority of participants obtained similar results in both scanning approaches. A few participants achieved significantly different measurement......An interlaboratory comparison on industrial X-ray Computed Tomography (CT) was organized by the Centre for Geometrical Metrology (CGM), Department of Mechanical Engineering, Technical University of Denmark (DTU) and carried as part of the Marie Curie ESR Project INTERAQCT. In the comparison, 22...... and concentricity. A multi-material length is also included in the comparison. Two different scanning approaches were considered within the comparison exercise for Assembly 1. The first approach, coded as “Own Choice”, does not apply any scanning restrictions on any of the scanning parameters. The second one, coded...

  15. Terson's Syndrome: Diagnostic Comparison of Ocular Sonography and CT.

    Science.gov (United States)

    Bäuerle, Jochen; Gross, Nikolai J; Egger, Karl; Neubauer, Jakob; Niesen, Wolf-Dirk; Buttler, Klaus-Jürgen; Lagrèze, Wolf A; Reinhard, Matthias

    2016-01-01

    To assess the accuracy of ocular B-mode sonography and of standard head computed tomography (CT) as screening tools for intraocular hemorrhages related to subarachnoid hemorrhage (SAH). 46 patients with spontaneous SAH were examined using ocular B-mode sonography and underwent funduscopy as gold standard for detection of ocular hemorrhages (OH). Additionally, all head CT scans done during the hospital stay of the study population were rated by a neuroradiologist for the presence of OH. Funduscopy revealed vitreous and/or preretinal hemorrhages in ten eyes and retinal hemorrhages in nine eyes. In comparison with funduscopy, ocular sonography showed a sensitivity and specificity for the detection of vitreous and/or preretinal hemorrhages of 100%, while identification of retinal hemorrhages was less reliable with a sensitivity/specificity of 44%/100%. Standard head CT showed a lower sensitivity/specificity of 60%/96% for vitreous and/or preretinal hemorrhages, and 32%/95% for the diagnosis of any ocular bleeding. Ocular sonography identifies SAH-related preretinal and vitreous hemorrhages with high accuracy and is superior to standard head CT. It may be considered as new and useful bedside diagnostic tool for routine clinical care of patients with SAH. Copyright © 2015 by the American Society of Neuroimaging.

  16. Helical structure of basic proteins from spermatozoa. Comparison with model peptides.

    Science.gov (United States)

    Verdaguer, N; Perelló, M; Palau, J; Subirana, J A

    1993-06-15

    We describe structural studies carried out with some basic proteins found in association with DNA in the spermatozoa of molluscs and echinoderms. We have studied proteins related to histone H1 as well as protamines. Structural prediction methods show that these proteins have a strong helical potential and contain several turns, mainly of the SPKK type. No beta structures were found. Strong structural similarities have been detected between distantly related species. The presence of helical regions is confirmed by circular dichroism in trifluoroethanol solution. The influence of the SPKK turns is also evident in the CD spectra. In proteins which contain a high percentage of arginine we conclude that conventional prediction methods should be modified in order to allow for a higher helical potential for this amino acid residue. Synthetic peptides with a sequence present in the C-terminal region of histone H1 have also been studied. It was found that octapeptides may only acquire a small amount of structure, whereas hexadecapeptides are 50-60% helical. These studies strongly suggest that both protamines and proteins related to the C-terminal part of histone H1 interact with DNA mainly in the alpha-helical conformation.

  17. Aortic non communicating dissections. A study with helical CT; Studio dell'ematoma intramurale aortico. Aspetti con Tomografia Computerizzata spirale

    Energy Technology Data Exchange (ETDEWEB)

    Midiri, M.; Strada, A.; Stabile Ianora, A.A.; Rotondo, A.; Angelelli, G. [Bari Univ., Bari (Italy). Dipt. di Medicina Interna e Medicina Pubblica, Sez. di Diagnostica per Immagini; Scialpi, M. [Ospedale SS. Annunziata, Taranto (Italy); D' Agostino, D.; De Luca Tupputi Schinosa, L. [Bari Univ., Bari (Italy). Dipt. Emergenze Trapianto d' Organo, Sez. di Cardiochirurgia

    2000-09-01

    The evaluate the signs of aortic intramural hematoma with helical CT and the diagnostic role of this technique in patients with this condition. It was reviewed the CT findings of 396 patients submitted to emergency examinations for suspected aortic dissection from 1995 to 1999. Only 18 patients (6 women and 12 men) had CT signs of aortic intramural hematoma. Helical CT studies were carried out with the following parameters: slice thickness 10 mm, reconstruction index 10, feed 1.5 mm, conventional algorithm with minimum values of 130 kV and 125mA. All patients were examined with dynamic contrast-enhanced CT, before and after a power injection of 130 mL ionic contrast material. It was studied: hematoma localization and longitudinal extension; thickness and density of aortic wall; presence and location of intimal calcifications; integrity of intimal wall; hemo mediastinum and/or hemo thorax. Aortic wall thickening appeared as a high density crescent-shaped area at baseline CT and had low density on enhanced images in all patients. Thickening was eccentric in 14/18 patients and concentric in 4/18 only; it always exceeded 4 mm. It was found some intimal calcifications in 8 patients and hemo thorax and/or hemo mediastinum in 9 patients. A patient with type A hematoma died of cardiac tamponade a few hours after CT diagnosis. Six patients (5 type B and 1 type A) underwent anti-hypertensive treatment and radiological follow-up. Eleven patients (6 type A and 5 type B) underwent prosthesis replacement and 5 of them (3 type A and 2 type B) died of postoperative complications. In the 5 type B patients surgery was performed because of treatment-resistant pain and of the onset of ischemic complications to abdominal organs caused by involvement of the main collateral branches of the aorta. One patient with type A hematoma was submitted to drug treatment because it was judged unresectable. Intramural hematoma of the aorta is a distinct pathological entity, which should not be

  18. Suspected ureteral colic: plain film and sonography vs unenhanced helical CT. A prospective study in 66 patients

    Energy Technology Data Exchange (ETDEWEB)

    Ripolles, Tomas; Agramunt, Marcos; Errando, Jose; Martinez, Maria Jesus [Department of Radiology, Hospital Universitario Dr. Peset, 90 Gaspar Aguilar Avenue, 46017, Valencia (Spain); Coronel, Belen [Department of Urology, Hospital Universitario Dr. Peset, 90 Gaspar Aguilar Avenue, 46017, Valencia (Spain); Morales, Maria [Research Unit, Hospital Universitario Dr. Peset, 90 Gaspar Aguilar Avenue, 46017, Valencia (Spain)

    2004-01-01

    The aim of this study was to compare the sensitivity and specificity of plain abdominal films plus ultrasound, vs nonenhanced CT for the diagnosis of ureteral colic in patients with acute flank pain. During a 4-month period, 66 patients (mean age 48 years) with acute flank pain were prospectively studied by means of plain abdominal film, US, and unenhanced CT. The presence of lithiasis and of obstructive uropathy signs were determined. The plain film was only used as a guide for the US exam. Clinical follow-up of all patients was obtained. Ureteral lithiasis was confirmed in 56 patients. The CT had a greater sensitivity (93 vs 79%) and negative predictive value (71 vs 46%) for the detection of lithiasis. The combination of lithiasis plus obstructive signs showed a sensitivity and a specificity of 100% for CT and of 100 and 90%, respectively, for US. The 11 lithiasis not detected by US were passed spontaneously (10 were <5 mm). Both techniques showed similar extraurinary pathology. Computed tomography is the most accurate technique for the detection of ureteral lithiasis; however, the combination of plain film and US is an alternative to nonenhanced CT with a lower sensitivity and radiation dose that has a good practical value. (orig.)

  19. Comparison of the aerodynamics of bridge cables with helical fillets and a pattern-indented surface

    DEFF Research Database (Denmark)

    Kleissl, K.; Georgakis, C.T.

    2012-01-01

    In this paper, the aerodynamics of bridge cables with helical fillets and a pattern-indented surface are examined. To this end, an extensive wind-tunnel test campaign was undertaken to measure the static force coefficients about the critical Reynolds number region, with varying relative cable...

  20. Generation of hybrid sinograms for the recovery of kV-CT images with metal artifacts for helical tomotherapy.

    Science.gov (United States)

    Jeon, Hosang; Park, Dahl; Youn, Hanbean; Nam, Jiho; Lee, Jayoung; Kim, Wontaek; Ki, Yongkan; Kim, Yong Ho; Lee, Ju Hye; Kim, Dongwon; Kim, Ho Kyung

    2015-08-01

    The overall goal of this study is to restore kilovoltage computed tomography (kV-CT) images which are disfigured by patients' metal prostheses. By generating a hybrid sinogram that is a combination of kV and megavoltage (MV) projection data, the authors suggest a novel metal artifact-reduction (MAR) method that retains the image quality to match that of kV-CT and simultaneously restores the information of metal prostheses lost due to photon starvation. CT projection data contain information about attenuation coefficients and the total length of the attenuation. By normalizing raw kV projections with their own total lengths of attenuation, mean attenuation projections were obtained. In the same manner, mean density projections of MV-CT were obtained by the normalization of MV projections resulting from the forward projection of density-calibrated MV-CT images with the geometric parameters of the kV-CT device. To generate the hybrid sinogram, metal-affected signals of the kV sinogram were identified and replaced by the corresponding signals of the MV sinogram following a density calibration step with kV data. Filtered backprojection was implemented to reconstruct the hybrid CT image. To validate the authors' approach, they simulated four different scenarios for three heads and one pelvis using metallic rod inserts within a cylindrical phantom. Five inserts describing human body elements were also included in the phantom. The authors compared the image qualities among the kV, MV, and hybrid CT images by measuring the contrast-to-noise ratio (CNR), the signal-to-noise ratio (SNR), the densities of all inserts, and the spatial resolution. In addition, the MAR performance was compared among three existing MAR methods and the authors' hybrid method. Finally, for clinical trials, the authors produced hybrid images of three patients having dental metal prostheses to compare their MAR performances with those of the kV, MV, and three existing MAR methods. The authors compared

  1. Generation of hybrid sinograms for the recovery of kV-CT images with metal artifacts for helical tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Hosang [Department of Radiation Oncology and Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan 626-770 (Korea, Republic of); Park, Dahl; Kim, Wontaek; Ki, Yongkan; Kim, Yong Ho; Lee, Ju Hye; Kim, Dongwon [Department of Radiation Oncology, Pusan National University Hospital, Busan 602-739 (Korea, Republic of); Youn, Hanbean [School of Mechanical Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Nam, Jiho; Lee, Jayoung [Department of Radiation Oncology, Pusan National University Yangsan Hospital, Yangsan 626-770 (Korea, Republic of); Kim, Ho Kyung, E-mail: hokyung@pusan.ac.kr [School of Mechanical Engineering and the Center for Advanced Medical Engineering Research, Pusan National University, Busan 609-735 (Korea, Republic of)

    2015-08-15

    Purpose: The overall goal of this study is to restore kilovoltage computed tomography (kV-CT) images which are disfigured by patients’ metal prostheses. By generating a hybrid sinogram that is a combination of kV and megavoltage (MV) projection data, the authors suggest a novel metal artifact-reduction (MAR) method that retains the image quality to match that of kV-CT and simultaneously restores the information of metal prostheses lost due to photon starvation. Methods: CT projection data contain information about attenuation coefficients and the total length of the attenuation. By normalizing raw kV projections with their own total lengths of attenuation, mean attenuation projections were obtained. In the same manner, mean density projections of MV-CT were obtained by the normalization of MV projections resulting from the forward projection of density-calibrated MV-CT images with the geometric parameters of the kV-CT device. To generate the hybrid sinogram, metal-affected signals of the kV sinogram were identified and replaced by the corresponding signals of the MV sinogram following a density calibration step with kV data. Filtered backprojection was implemented to reconstruct the hybrid CT image. To validate the authors’ approach, they simulated four different scenarios for three heads and one pelvis using metallic rod inserts within a cylindrical phantom. Five inserts describing human body elements were also included in the phantom. The authors compared the image qualities among the kV, MV, and hybrid CT images by measuring the contrast-to-noise ratio (CNR), the signal-to-noise ratio (SNR), the densities of all inserts, and the spatial resolution. In addition, the MAR performance was compared among three existing MAR methods and the authors’ hybrid method. Finally, for clinical trials, the authors produced hybrid images of three patients having dental metal prostheses to compare their MAR performances with those of the kV, MV, and three existing MAR

  2. Helicity scalings

    Energy Technology Data Exchange (ETDEWEB)

    Plunian, F [ISTerre, CNRS, Universite Joseph Fourier, Grenoble (France); Lessinnes, T; Carati, D [Physique Statistique et Plasmas, Universite Libre de Bruxelles (Belgium); Stepanov, R, E-mail: Franck.Plunian@ujf-grenoble.fr [Institute of Continuous Media Mechanics of the Russian Academy of Science, Perm (Russian Federation)

    2011-12-22

    Using a helical shell model of turbulence, Chen et al. (2003) showed that both helicity and energy dissipate at the Kolmogorov scale, independently from any helicity input. This is in contradiction with a previous paper by Ditlevsen and Giuliani (2001) in which, using a GOY shell model of turbulence, they found that helicity dissipates at a scale larger than the Kolmogorov scale, and does depend on the helicity input. In a recent paper by Lessinnes et al. (2011), we showed that this discrepancy is due to the fact that in the GOY shell model only one helical mode (+ or -) is present at each scale instead of both modes in the helical shell model. Then, using the GOY model, the near cancellation of the helicity flux between the + and - modes cannot occur at small scales, as it should be in true turbulence. We review the main results with a focus on the numerical procedure needed to obtain accurate statistics.

  3. Radiation dose reduction at a price: the effectiveness of a male gonadal shield during helical CT scans

    Directory of Open Access Journals (Sweden)

    Erdi Yusuf E

    2007-03-01

    Full Text Available Abstract Background It is estimated that 60 million computed tomography (CT scans were performed during 2006, with approximately 11% of those performed on children age 0–15 years. Various types of gonadal shielding have been evaluated for reducing exposure to the gonads. The purpose of this study was to quantify the radiation dose reduction to the gonads and its effect on image quality when a wrap-around male pediatric gonad shield was used during CT scanning. This information is obtained to assist the attending radiologist in the decision to utilize such male gonadal shields in pediatric imaging practice. Methods The dose reduction to the gonads was measured for both direct radiation and for indirect scattered radiation from the abdomen. A 6 cm3 ion chamber (Model 10X5-6, Radcal Corporation, Monrovia, CA was placed on a Humanoid real bone pelvic phantom at a position of the male gonads. When exposure measurements with shielding were made, a 1 mm lead wrap-around gonadal shield was placed around the ion chamber sensitive volume. Results The use of the shields reduced scatter dose to the gonads by a factor of about 2 with no appreciable loss of image quality. The shields reduced the direct beam dose by a factor of about 35 at the expense of extremely poor CT image quality due to severe streak artifacts. Conclusion Images in the direct exposure case are not useful due to these severe artifacts and the difficulties in positioning these shields on patients in the scatter exposure case may not be warranted by the small absolute reduction in scatter dose unless it is expected that the patient will be subjected to numerous future CT scans.

  4. Lung cancer screening with low-dose helical CT in Korea: experiences at the Samsung Medical Center.

    Science.gov (United States)

    Chong, Semin; Lee, Kyung Soo; Chung, Myung Jin; Kim, Tae Sung; Kim, Hojoong; Kwon, O Jung; Choi, Yoon-Ho; Rhee, Chong H

    2005-06-01

    To determine overall detection rates of lung cancer by low-dose CT (LDCT) screening and to compare histopathologic and imaging differences of detected cancers between high- and low-risk groups, this study included 6,406 asymptomatic Korean adults with >or=45 yr of age who underwent LDCT for lung cancer screening. All were classified into high- (>or=20 pack-year smoking; 3,353) and low-risk (3,053; <20 pack-yr smoking and non-smokers) groups. We compared CT findings of detected cancers and detection rates between high- and low-risk. At initial CT, 35% (2,255 of 6,406) had at least one or more non-calcified nodule. Lung cancer detection rates were 0.36% (23 of 6,406). Twenty-one non-small cell lung cancers appeared as solid (n=14) or ground-glass opacity (GGO) (n=7) nodules. Cancer likelihood was higher in GGO nodules than in solid nodules (p<0.01). Fifteen of 23 cancers occurred in high-risk group and 8 in low-risk group (p=0.215). Therefore, LDCT screening help detect early stage of lung cancer in asymptomatic Korean population with detection rate of 0.36% on a population basis and may be useful for discovering early lung cancer in low-risk group as well as in high-risk group.

  5. Limited cone-beam computed tomography imaging of the middle ear: a comparison with multislice helical computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Peltonen, L.I.; Aarnisalo, A.A.; Kortesniemi, M.K.; Suomalainen, A.; Jero, J.; Robinson, S. [Dept. of Otorhinolaryngology and Dept. of Radiology, Helsinki Univ. Central Hospital (Finland)

    2007-02-15

    Purpose: To determine the applicability of cone-beam computed tomography (CBCT) in otological imaging, and to compare its accuracy with the routinely used multislice helical CT (MSCT) for imaging of the middle- and inner-ear areas. Material and Methods: Thirteen unoperated human cadaver temporal bones were imaged with CBCT and MSCT. Sixteen landmarks of the middle and adjacent inner ear were evaluated and compared for their conspicuity according to a modified Likert scale. Total scores and scores for subgroups including landmarks of specific clinical interest were also compared. Results: No significant differences were found between the imaging techniques or subgroups when scores of individual structures were compared. While the middle ear itself was visible in all cases with CBCT, parts of the inner ear were 'cut off' in four cases due to the limited field of view. For the same reason, the evaluation of the whole mastoid was not possible with CBCT. The cochlear and vestibular aqueducts were not visualized in either CT techniques. The contrast-to-noise ratio was more than 50% lower in CBCT than in MSCT, but still adequate for diagnostic task. Conclusion: CBCT proved to be at least as accurate as routinely used MSCT in revealing the clinically and surgically important middle-ear structures. The results show that high-quality imaging of the middle ear is possible with the current CBCT device.

  6. Quantitative comparison of PET performance—Siemens Biograph mCT and mMR

    National Research Council Canada - National Science Library

    Karlberg, Anna M; Sæther, Oddbjørn; Eikenes, Live; Goa, Pål Erik

    2016-01-01

    ...) and Siemens Biograph mCT (PET/CT).A direct quantitative comparison of the performance characteristics between the mMR and mCT system was performed according to National Electrical Manufacturers Association (NEMA) NU 2-2007 protocol...

  7. Quantitative comparison of PET performance-Siemens Biograph mCT and mMR

    National Research Council Canada - National Science Library

    Karlberg, Anna M; Sæther, Oddbjørn; Eikenes, Live; Goa, Pål Erik

    2016-01-01

    ...) and Siemens Biograph mCT (PET/CT). A direct quantitative comparison of the performance characteristics between the mMR and mCT system was performed according to National Electrical Manufacturers Association (NEMA) NU 2-2007 protocol...

  8. Interobserver variability in visual evaluation of thoracic CT scans and comparison with automatic computer measurements of CT lung density

    DEFF Research Database (Denmark)

    Winkler Wille, Mathilde Marie; Thomsen, Laura Hohwü; Dirksen, Asger

    2012-01-01

    in emphysema grading. However, the agreement with the CT lung density measurement was poor, indicating that the two types of evaluation represent different aspects of emphysema. Most likely, they should be seen as complementary rather than competitive evaluations. Future comparison with physiological tests......Introduction – Emphysema is defined by pathology, but is most precisely evaluated in vivo by computed tomography (CT). Aims – were to determine the reproducibility of visual evaluation of emphysema, i.e. the observer variability, and furthermore to compare the visual evaluations to automatic CT...... might elucidate the reason for differences and demonstrate the usefulness of these evaluations....

  9. Comparison of CT and PET/CT for biopsy guidance in oncological patients

    Energy Technology Data Exchange (ETDEWEB)

    Cerci, Juliano J.; Bogoni, Mateos; Cunha Pereira, Carlos; Cerci, Rodrigo J.; Krauzer, Cassiano; Vicente Vitola, Joao [Quanta - Diagnostico e Terapia, Curitiba, PR (Brazil); Tabacchi, Elena; Fanti, Stefano [University Hospital S. Orsola-Malpighi, Nuclear Medicine Department, Bologna (Italy); Delbeke, Dominique [Vanderbilt University, Nashville, TN (United States); Giacometti Sakamoto, Danielle [Byori - Laboratorio de Patologia, Curitiba (Brazil)

    2017-08-15

    To compare FDG PET/CT and CT for the guidance of percutaneous biopsies with histological confirmation of lesions. We prospectively evaluated 323 patients of whom 181 underwent FDG PET/CT-guided biopsy (total 188 biopsies) and 142 underwent CT-guided biopsy (total 146 biopsies). Biopsies were performed using the same PET/CT scanner with a fluoroscopic imaging system. Technical feasibility, clinical success and complication rates in the two groups were evaluated. Of the 188 biopsies with PET/CT guidance, 182 (96.8%) were successful with conclusive tissue samples obtained and of the 146 biopsies with CT guidance, 137 (93.8%) were successful. Therefore, 6 of 188 biopsies (3.1%) with PET/CT guidance and 9 of 146 (6.1%) with CT guidance were inconclusive (p = 0.19). Due to inconclusive histological results, 4 of the 188 lesions (2.1%) were rebiopsied with PET/CT guidance and 3 of 146 lesions (2.0%) were rebiopsied with CT guidance. Histology demonstrated that 142 of 188 lesions (75.5%) were malignant, and 40 (21.2%) were benign in the PET/CT-guided group, while 89 of 146 lesions (60.9%) were malignant and 48 (32.8%) were benign in the CT-guided group (p = 0.004 and 0.01, respectively). Patients with a histological diagnosis of benign lesion had no recurrence of disease with a minimum of 6 months follow-up. Of the 188 PET/CT-guided biopsies, 6 (3.1%) were repeat biopsies due to a previous nondiagnostic CT-guided biopsy performed in a different diagnostic centre. The interval between the two biopsies was less than a month in all cases. Histology revealed five malignant lesions and one benign lesion among these. The complication rate in the PET/CT-guided biopsy group was 12.7% (24 of 188), while in the CT-guided group, was 9.5% (14 of 146, p = 0.26). Therefore, there was no significant difference in complication rates between PET/CT and CT guidance. PET/CT-guided biopsy is already known to be a feasible and accurate method in the diagnostic work-up of suspected malignant

  10. Traumatic brain injury: Comparison between autopsy and ante-mortem CT.

    Science.gov (United States)

    Panzer, Stephanie; Covaliov, Lidia; Augat, Peter; Peschel, Oliver

    2017-11-01

    The aim of this study was to compare pathological findings after traumatic brain injury between autopsy and ante-mortem computed tomography (CT). A second aim was to identify changes in these findings between the primary posttraumatic CT and the last follow-up CT before death. Through the collaboration between clinical radiology and forensic medicine, 45 patients with traumatic brain injury were investigated. These patients had undergone ante-mortem CT as well as autopsy. During autopsy, the brain was cut in fronto-parallel slices directly after removal without additional fixation or subsequent histology. Typical findings of traumatic brain injury were compared between autopsy and radiology. Additionally, these findings were compared between the primary CT and the last follow-up CT before death. The comparison between autopsy and radiology revealed a high specificity (≥80%) in most of the findings. Sensitivity and positive predictive value were high (≥80%) in almost half of the findings. Sixteen patients had undergone craniotomy with subsequent follow-up CT. Thirteen conservatively treated patients had undergone a follow-up CT. Comparison between the primary CT and the last ante-mortem CT revealed marked changes in the presence and absence of findings, especially in patients with severe traumatic brain injury requiring decompression craniotomy. The main pathological findings of traumatic brain injury were comparable between clinical ante-mortem CT examinations and autopsy. Comparison between the primary CT after trauma and the last ante-mortem CT revealed marked changes in the findings, especially in patients with severe traumatic brain injury. Hence, clinically routine ante-mortem CT should be included in the process of autopsy interpretation. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  11. Thermal performance comparison of oscillating heat pipes with and without helical micro-grooves

    Science.gov (United States)

    Qu, Jian; Li, Xiaojun; Xu, Qian; Wang, Qian

    2017-06-01

    This paper presents an experimental investigation to compare the thermal performance of three closed loop oscillating heat pipes (OHPs) with and without internal helical microgrooves at vertical and horizontal orientations. All of these OHPs were made from copper tubes and have three turns with lengths of 70, 230 and 110 mm at the evaporator, adiabatic and condenser sections, respectively. Deionized water was used as the working fluid at a volumetric filling ratio of 50%. The internal diameters (IDs) of two smooth-tube OHPs are 4.0 and 4.8 mm, respectively, and the internal diameter of micro-grooved OHP without groove structures is about 4.5 mm. Experimental results demonstrated that the addition of groove structures make the OHP remarkably outperform smooth-tube OHPs in both effective thermal conductivity and thermal resistance. The thermal resistance of vertically-oriented micro-grooved OHP could be lowered to 0.057 °C/W associated with an effective thermal conductivity of 6.1 × 104 W/ (m·K) at the input heat flux of 3.8 × 104 W/m2. Compared to smooth-tube OHPs, preliminary mechanism analysis reveals that local heat transfer coefficients both at the heating and cooling sections of micro-grooved OHP could be significantly improved. Moreover, enhanced liquid backflow to the evaporator due to microgroove-induced capillarity is also responsible for the OHP performance enhancement.

  12. Profile stiffness measurements in the Helically Symmetric experiment and comparison to nonlinear gyrokinetic calculations

    Energy Technology Data Exchange (ETDEWEB)

    Weir, G. M.; Faber, B. J.; Likin, K. M.; Talmadge, J. N.; Anderson, D. T.; Anderson, F. S. B. [HSX Plasma Laboratory, University of Wisconsin–Madison, Madison, Wisconsin 53706 (United States)

    2015-05-15

    Stiffness measurements are presented in the quasi-helically symmetric experiment (HSX), in which the neoclassical transport is comparable to that in a tokamak and turbulent transport dominates throughout the plasma. Electron cyclotron emission is used to measure the local electron temperature response to modulated electron cyclotron resonant heating. The amplitude and phase of the heat wave through the steep electron temperature gradient (ETG) region of the plasma are used to determine a transient electron thermal diffusivity that is close to the steady-state diffusivity. The low stiffness in the region between 0.2 ≤ r/a ≤ 0.4 agrees with the scaling of the steady-state heat flux with temperature gradient in this region. These experimental results are compared to gyrokinetic calculations in a flux-tube geometry using the gyrokinetic electromagnetic numerical experiment code with two kinetic species. Linear simulations show that the ETG mode may be experimentally relevant within r/a ≤ 0.2, while the Trapped Electron Mode (TEM) is the dominant long-wavelength microturbulence instability across most of the plasma. The TEM is primarily driven by the density gradient. Non-linear calculations of the saturated heat flux driven by the TEM and ETG bracket the experimental heat flux.

  13. Thermal performance comparison of oscillating heat pipes with and without helical micro-grooves

    Science.gov (United States)

    Qu, Jian; Li, Xiaojun; Xu, Qian; Wang, Qian

    2017-11-01

    This paper presents an experimental investigation to compare the thermal performance of three closed loop oscillating heat pipes (OHPs) with and without internal helical microgrooves at vertical and horizontal orientations. All of these OHPs were made from copper tubes and have three turns with lengths of 70, 230 and 110 mm at the evaporator, adiabatic and condenser sections, respectively. Deionized water was used as the working fluid at a volumetric filling ratio of 50%. The internal diameters (IDs) of two smooth-tube OHPs are 4.0 and 4.8 mm, respectively, and the internal diameter of micro-grooved OHP without groove structures is about 4.5 mm. Experimental results demonstrated that the addition of groove structures make the OHP remarkably outperform smooth-tube OHPs in both effective thermal conductivity and thermal resistance. The thermal resistance of vertically-oriented micro-grooved OHP could be lowered to 0.057 °C/W associated with an effective thermal conductivity of 6.1 × 104 W/ (m·K) at the input heat flux of 3.8 × 104 W/m2. Compared to smooth-tube OHPs, preliminary mechanism analysis reveals that local heat transfer coefficients both at the heating and cooling sections of micro-grooved OHP could be significantly improved. Moreover, enhanced liquid backflow to the evaporator due to microgroove-induced capillarity is also responsible for the OHP performance enhancement.

  14. Dosimetric comparison of helical tomotherapy and dynamic conformal arc therapy in stereotactic radiosurgery for vestibular schwannomas.

    Science.gov (United States)

    Lee, Tsair-Fwu; Chao, Pei-Ju; Wang, Chang-Yu; Lan, Jen-Hong; Huang, Yu-Je; Hsu, Hsuan-Chih; Sung, Chieh-Cheng; Su, Te-Jen; Lian, Shi-Long; Fang, Fu-Min

    2011-01-01

    The dosimetric results of stereotactic radiosurgery (SRS) for vestibular schwannoma (VS) performed using dynamic conformal arc therapy (DCAT) with the Novalis system and helical TomoTherapy (HT) were compared using plan quality indices. The HT plans were created for 10 consecutive patients with VS previously treated with SRS using the Novalis system. The dosimetric indices used to compare the techniques included the conformity index (CI) and homogeneity index (HI) for the planned target volume (PTV), the comprehensive quality index (CQI) for nine organs at risk (OARs), gradient score index (GSI) for the dose drop-off outside the PTV, and plan quality index (PQI), which was verified using the plan quality discerning power (PQDP) to incorporate 3 plan indices, to evaluate the rival plans. The PTV ranged from 0.27-19.99 cm(3) (median 3.39 cm(3)), with minimum required PTV prescribed doses of 10-16 Gy (median 12 Gy). Both systems satisfied the minimum required PTV prescription doses. HT conformed better to the PTV (CI: 1.51 ± 0.23 vs. 1.94 ± 0.34; p dose in 4 OARs and significant lower mean dose in 1 OAR; by contrast, DCAT had a significantly lower maximum dose in 1 OAR and significant lower mean dose in 2 OARs, with the CQI of the 9 OARs = 0.92 ± 0.45. Plan analysis using PQI (HT 0.37 ± 0.12 vs. DCAT 0.65 ± 0.08; p dose conformity and similar dose homogeneity but worse dose gradient than DCAT. Plan analysis confirmed the dosimetric advantage of HT, although not all indices revealed a better outcome for HT. Whether this dosimetric advantage translates into a clinical benefit deserves further investigation. Copyright © 2011 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  15. [Comparison between experimentally and theoretically determined CT values].

    Science.gov (United States)

    Christ, G; Schmitt, W G

    1983-09-01

    The article presents two methods for the theoretical determination of CT values. These methods involve relatively little work and cost and enable at least an estimation of the CT value of any object to be examined. The results are compared with the experimental data, and possible sources of errors are shown. The article concludes with a discussion of a few examples from actual practice.

  16. Interobserver variability in visual evaluation of thoracic CT scans and comparison with automatic computer measurements of CT lung density

    DEFF Research Database (Denmark)

    Winkler Wille, Mathilde Marie; Thomsen, Laura Hohwü; Dirksen, Asger

    2012-01-01

    Introduction – Emphysema is defined by pathology, but is most precisely evaluated in vivo by computed tomography (CT). Aims – were to determine the reproducibility of visual evaluation of emphysema, i.e. the observer variability, and furthermore to compare the visual evaluations to automatic CT...... information. The lung was segmented automatically by in-house developed computer software, and the percentage of pixels below -950 HU was used as a surrogate marker for emphysema. The observer variability, as well as the correlation with the lung density measurements, was analysed using Spearman’s rank...... in emphysema grading. However, the agreement with the CT lung density measurement was poor, indicating that the two types of evaluation represent different aspects of emphysema. Most likely, they should be seen as complementary rather than competitive evaluations. Future comparison with physiological tests...

  17. [CT strategy for patients with suspected acute appendicitis; comparison of conditional and immediate CT].

    Science.gov (United States)

    Atema, Jasper J; Gans, Sarah L; van Randen, Adrienne; Laméris, Wytze; van Es, H W Wouter; van Heesewijk, Johannes P M; van Ramshorst, Bert; Bouma, Wim H; ten Hove, Wim; van Keulen, Esteban M; Dijkgraaf, Marcel G W; Bossuyt, Patrick M M; Stoker, Jaap; Boermeester, Marja A

    2015-01-01

    To compare the diagnostic accuracy of conditional CT strategy, i.e. CT if ultrasound findings are negative or inconclusive, with immediate CT strategy for patients with suspected appendicitis. Subanalysis of a prospective multicenter diagnostic accuracy study. Only data of patients with signs of appendicitis based on medical history, physical examination, and laboratory tests were analyzed. All patients underwent both ultrasound and CT. Images of each were read by different observers who were blinded to the results of the other imaging modality. The observer then selected the most likely diagnosis. These diagnoses were compared with the reference standard, i.e. final diagnoses as assigned by an expert panel based on all available data and at least 6 months of follow-up. A total of 422 patients with suspected appendicitis were included. In 251 patients the final diagnosis was acute appendicitis (59%). In 199 patients (47%), ultrasound findings were inconclusive or negative. Use of conditional CT strategy resulted in correctly identified number of correctly identified patients with appendicitis, i.e. 96% (95% CI 93-98), versus 95% identified by immediate CT (95% CI 91-97). However, conditional CT strategy resulted in more false positive diagnoses compared with immediate CT (39 versus 22), had an accompanying lower specificity of 77% (95% CI 70-83) versus 87% (95% CI 81-91), and a lower positive predictive value of 86% (95% CI 81-90) versus 92% (95% CI 87-95). Use of a conditional CT strategy results in exactly the same number of patients with correctly identified acute appendicitis while halving the number of CTs needed. However, conditional strategy results in more false positive diagnoses.

  18. Incidental physiological sliding hiatal hernia: a single center comparison study between CT with water enema and CT colonography.

    Science.gov (United States)

    Revelli, Matteo; Furnari, Manuele; Bacigalupo, Lorenzo; Paparo, Francesco; Astengo, Davide; Savarino, Edoardo; Rollandi, Gian Andrea

    2015-08-01

    hernias. Comparison CT of the 28 patients with a hiatal hernia at CTC showed the absence of the hernia in 57.1 % (16/28) patients, including 68.8 % (11/16) and 50 % (5/10) of small and moderate hernias. The prevalence of sliding hiatal hernias in the external control group was 22 % (44/200), significantly lower than the CT-WE and CTC cohorts' prevalence of 51 % (p hiatal hernias should not be reported in patients with symptoms not related to reflux disease undergoing CT-WE or CTC: When encountering these findings, accurate anamnesis and review of medical history looking for GERD-related symptoms are essential, in order to address these patients to a correct diagnostic iter, taking advantage from more appropriate techniques such as endoscopy or functional techniques.

  19. CT-diskography in patients with sciatica. Comparison with plain CT and MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Dullerud, R. [Ullevaal Univ. Hospital, Oslo (Norway). Section of Neuroradiology; Johansen, J.G. [Ullevaal Univ. Hospital, Oslo (Norway). Section of Neuroradiology

    1995-09-01

    The findings at CT-diskography (CT-D), including recording of the pain introduced at contrast injection, were compared with plain CT and MR imaging in 111 disks in 101 patients aged 18 to 68 years. Six disks which were normal at CT had normal CT-D and 5 of them had normal signal on MR imaging. The degree of annular degeneration and the depth of the annular tears were significantly associated with each other and with loss of disk height, but not with size or location of the hernias. Only the depth of the tears was significantly associated with loss of signal on MR. However, frequently complete annular tears and severe annular degeneration were seen in association with small bulges and hernias, even in disks with normal or slightly reduced signal on MR and with normal height. The type and intensity of the pain introduced were associated with each other and with the depth of the annular tears, but not with the degree of annular degeneration, size of the hernia or the MR signal intensity of the disks. Annular degeneration and tears on one hand, and the type and intensity of pain introduced on the other, see to be related rather than separate phenomena. (orig./MG).

  20. Comparison of advanced iterative reconstruction methods for SPECT/CT

    Energy Technology Data Exchange (ETDEWEB)

    Knoll, Peter; Koechle, Gunnar; Mirzaei, Siroos [Wilhelminenspital, Vienna (Austria). Dept. of Nuclear Medicine and PET Center; Kotalova, Daniela; Samal, Martin [Charles Univ. Prague, Prague (Czech Republic); Kuzelka, Ivan; Zadrazil, Ladislav [Hospital Havlickuv Brod (Czech Republic); Minear, Greg [Landesklinikum St. Poelten (Austria). Dept. of Internal Medicine II; Bergmann, Helmar [Medical Univ. of Vienna (Austria). Center for Medical Physics and Biomedical Engineering

    2012-07-01

    Aim: Corrective image reconstruction methods which produce reconstructed images with improved spatial resolution and decreased noise level became recently commercially available. In this work, we tested the performance of three new software packages with reconstruction schemes recommended by the manufacturers using physical phantoms simulating realistic clinical settings. Methods: A specially designed resolution phantom containing three {sup 99m}Tc lines sources and the NEMA NU-2 image quality phantom were acquired on three different SPECT/CT systems (General Electrics Infinia, Philips BrightView and Siemens Symbia T6). Measurement of both phantoms was done with the trunk filled with a {sup 99m}Tc-water solution. The projection data were reconstructed using the GE's Evolution for Bone {sup registered}, Philips Astonish {sup registered} and Siemens Flash3D {sup registered} software. The reconstruction parameters employed (number of iterations and subsets, the choice of post-filtering) followed theses recommendations of each vendor. These results were compared with reference reconstructions using the ordered subset expectation maximization (OSEM) reconstruction scheme. Results: The best results (smallest value for resolution, highest percent contrast values) for all three packages were found for the scatter corrected data without applying any post-filtering. The advanced reconstruction methods improve the full width at half maximum (FWHM) of the line sources from 11.4 to 9.5 mm (GE), from 9.1 to 6.4 mm (Philips), and from 12.1 to 8.9 mm (Siemens) if no additional post filter was applied. The total image quality control index measured for a concentration ratio of 8:1 improves for GE from 147 to 189, from 179. to 325 for Philips and from 217 to 320 for Siemens using the reference method for comparison. The same trends can be observed for the 4:1 concentration ratio. The use of a post-filter reduces the background variability approximately by a factor of two, but

  1. MR imaging of gastric carcinoma; comparison with CT

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Mun; Kim, Choon Yul; Chun, Kyung Ah; Kim, Hyang Sun; Shinn, Kyung Sub [Catholic University Medical College, Seoul (Korea, Republic of)

    1994-08-15

    To assess the value of MR imaging compared to CT for the staging of gastric carcinoma when body-wrap-around surface coil, intravenous glucagon, motion suppression technique and effervescent granules are used. CT and MRI were performed for thirty-five patients with gastric carcinoma. Postcontrast CT scan was performed immediately after oral effervescent granules and Buscopan were given. Before MR imaging, BWA surface coil was wrapped around thr upper abdomen. T1 coronal, sagittal and axial SE images (TR/TE=400/15 msec) were obtained immediately after oral effervescent granules and glucagon were given. Respiratory compensation and presaturation techniques were used for each imaging. Three radiologists evaluated independently for randomly mixed 70 sets of CT and MR images. The signal intensity of gastric mass and enlarged lymph nodes were compared to the signal intensity of the adjacent pancreas, liver and spleen to evaluate any discriminating features between them. The accuracy in the diagnosis of pancreatic invasion was 83.8% on MRI and 74.3% on CT (p < 0.05). The accuracy of MRI and CT was 77.1% and 72.4% in detecting of gastric tumor respectively (p > 0.05), 73.3% and 68.6% in gastric serosal invasion (p < 0.05). 50.5% and 42.9% in lymph node metastasis (p < 0.05). The gastric mass and enlarged lymph nodes were hyperintense to the intensity of pancreas and liver in more than 78% of cases. MRI was comparable to CT scan for the staging of gastric carcinoma. Therefor, MRI could be used as an alternative or adjunctive diagnostic modality in the staging of gastric carcinoma.

  2. Patient doses in chest CT examinations: Comparison of various CT scanners

    Directory of Open Access Journals (Sweden)

    Božović Predrag

    2013-01-01

    Full Text Available This paper presents results from study on patient exposure level in chest CT examinations. CT scanners used in this study were various Siemens and General Electric (GE models. Data on patient doses were collected for adult and pediatric patients. Doses measured for adult patients were lower then those determined as Diagnostic Reference Levels (DRL for Europe, while doses for pediatric patients were similar to those found in published data. As for the manufactures, slightly higher doses were measured on GE devices, both for adult and pediatric patients.

  3. Contrast-enhanced helical CT in sigmoid diverticulitis. Findings and impact on diagnosis and treatment; Ruolo della tomografia computerizzata spirale nella diverticolite del sigma e implicazioni diagnostico-terapeutiche

    Energy Technology Data Exchange (ETDEWEB)

    Scaglione, M.; Romano, L.; Pinto, A.; De Lutio di Castelguidone, E.; Giovine, S.; Pinto, F. [Azienda Ospedaliera di Rilievo Nazionale A. Cardarelli, Naples (Italy). Dipt. di Diagnostica per Immagini; Forner, A.L. [Azienda Ospedaliera di Rilievo Nazionale A. Cardarelli, Naples (Italy). Dipt. di Chirurgia d' Urgenza; Grassi, R. [Naples Univ. II, Naples (Italy). Ist. di Radiologia

    2000-03-01

    Aim of this retrospective study was to assess the capability of contrast-enhanced helical computerised tomography (CT) in sigmoid diverticulitis, especially relative to selection of the appropriate treatment. The findings of 41 patients were reviewed from 1998 to 1999 June. Contrast-enhanced helical CT is the imaging modality of choice in assessing mild or severe acute diverticulitis because it provides useful information for appropriate treatment planning in the emergency setting. This technique is most useful in questionable cases and in patients with suspected severe diverticulitis where a choice must be made between different treatment options. [Italian] Scopo di questo studio retrospettivo e' illustrare i molteplici aspetti radiologici della flogosi diverticolare sigmoidea con tomografia computerizzata (TC) spirale, con specifico riguardo alle implicazioni terapeutiche che scaturiscono dall'analisi e dal confronto dei reperti TC con i riscontri clinici e chirurgici. Sono analizzati e discussi i risultati dello studio di 41 pazienti consecutivi con diverticolite del sigma esaminati dal giugno del 1998 al giugno del 1999. La TC spirale ha fornito dettagli precisi sul danno anatomo-chirurgico dell'ansa e sulle strutture limitrofe coinvolte consentendo di differenziare la diverticolite lieve da quella grave. Il suo ruolo si configura nei pazienti critici difficilmente classificabili e nelle sospette diverticoliti gravi o complicate per la molteplicita' delle scelte terapeutiche.

  4. Absorbed dose during helical CT acquisition: influence of acquisition parameters; Dose delivree lors d'un examen scanner en acquisition helicoidale influence des parametres d'acquisition

    Energy Technology Data Exchange (ETDEWEB)

    Giraud, J.Y.; Sage, J.; Dusserre, A.; Bolla, M.; Kolodie, H. [Centre Hospitalier Universitaire, Service de Cancerologie-Radiotherapie, 38 - Grenoble (France); Taisant, D. [Clinique du Mail, Service de Radiotherapie, 38 - Grenoble (France); Coulomb, M.; Ferretti, G. [Centre Hospitalier Universitaire, Service Central de Radiologie et Imagerie Medicale, 38 - Grenoble (France); Barthelemy, R.; Aumont, B. [Clinique du Mail, Service de Radiologie, 38 - Grenoble (France)

    2001-01-01

    Purpose. European directive 97/43 specifies that the dose delivered to the patient during a radiological procedure should be estimated. In order to prepare for implementation of this new regulation, we have studied the dose delivered during spiral CT acquisition. Materials and methods. We have studied the influence of slice thickness, pitch, tube voltage and intensity, and acquisition volume length. We present measurements for single and dual detector CT scanners. We used a pencil ionization chamber to measure air kerma. We measured absorbed dose in water with a waterproof ionization chamber set in a semi-customized phantom filled with water. Chambers were set on the rotation axis of the CT scanners. We studied the dose outside the acquisition volume. Results. We quantified the influence of each parameter on the absorbed dose. We used our measurements to calculate the dose for different acquisition protocols. Also we evaluated the dose to organs distant from the acquisition area. Conclusion. This study is one step toward a systematic estimation of the dose delivered to patient during helical CT exams. To use these results in daily practice, we have to develop software using our measurements. (authors)

  5. Comparison of digital subtraction angiography, CT angiography, and ultrasonic doppler examination in the evaluation of penile arterial lesions

    Energy Technology Data Exchange (ETDEWEB)

    Kawanisi, Yasuo; Kimura, Kazunori; Lee, Kyong Soo; Koizumi, Takahiro; Nakatsuji, Hiroyoshi; Kojima, Keiji; Yamamoto, Akira; Numata, Akira [Takamatsu Red Cross Hospital (Japan)

    2001-11-01

    CT angiography reconstructed by a multidetector-row helical CT scanner is a newly developed form of imaging. We compared CT angiography and ultrasonic Doppler examination with digital subtraction angiography (DSA) in the diagnosis of arterial lesion. Eighteen patients with arteriogenic erectile dysfunction (ED) underwent color Doppler study DSA, and CT angiography after providing informed consent. The CT angiography images were obtained by a multidetector-row helical CT scanner, Asteion TSX021A (TOSHIBA). We injected prostaglandin E{sub 1} into the penile cavernous body, and then rapidly infused nonionic contrast medium into the antecubital vein. DSA and CT angiography images of the bilateral internal pudendal arteries and cavernous arteries were examined for stenotic lesions or occlusion. We also compared the peak systolic blood flow velocity in the cavernous artery measured by color Doppler ultrasound with CT angiography and DSA. The CT anigography and color Doppler studies were performed on an outpatient basis, but DSA required hospitalization. In the 36 internal pudendal arteries, DSA represented 22 normal arteries and 14 stenosis or occlusions. CT angiography showed 15 normal arteries and 21 occlusions. For the diagnosis of stenosis or occlusion in the internal pudendal artery, the CT angiography image had a good agreement, with a sensitivity of 1.00, specificity of 0.68, and accuracy of 0.81. For diagnosis in the cavernous artery, CT angiography image also showed a good agreement with DSA; however, the quality of the images of fine arteries was better in the DSA images. The inferior view and internal view of the pelvis in CT angiography were helpful for visulaizing the internal pudendal artery, especially at the pubic bone. There was insufficient correlation between peak systolic blood flow velocity and DSA findings. There were no serious complications involved in either examination. CT angiography has not yet reached the same level as DSA in the evaluation

  6. Initial experience with lung-MRI at 3.0 T: Comparison with CT and clinical data in the evaluation of interstitial lung disease activity

    Energy Technology Data Exchange (ETDEWEB)

    Lutterbey, G. [Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn (Germany)]. E-mail: goetz.lutterbey@ukb.uni-bonn.de; Grohe, C. [Department of Internal Medicine, University of Bonn (Germany); Gieseke, J. [PHILIPS Medical Systems, Best (Netherlands); Falkenhausen, M. von [Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn (Germany); Morakkabati, N. [Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn (Germany); Wattjes, M.P. [Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn (Germany); Manka, R. [Department of Internal Medicine, University of Bonn (Germany); Trog, D. [Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn (Germany); Schild, H.H. [Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn (Germany)

    2007-02-15

    Objectives: We evaluated the feasibility of highfield lung-MRI at 3.0 T. A comparison with Computed Tomography (CT) and clinical data regarding the assessment of inflammatory activity in patients with diffuse lung disease was performed. Material and methods: Prospective evaluation of 21 patients (15 males, 6 females, 43-80 y) with diffuse lung diseases who underwent clinical work-up inclusive laboratory tests, lung-function tests and transbronchial biopsy. After routine helical CT (additional 12 HRCT) a lung-MRI (3.0 Intera, Philips Medical Systems, Best, The Netherlands) using a T2-weighted, cardiac and respiratory triggered Fast-Spinecho-Sequence (TE/TR = 80/1500-2500 ms, 22 transverse slices, 7/2 mm slice-thickness/-gap) was performed. A pneumologist classified the cases into two groups: A = temporary acute interstitial disease or chronic interstitial lung disease with acute episode or superimposed infection/B = burned out interstitial lung disease without activity. Two blinded CT-radiologists graded the cases in active/inactive disease on the basis of nine morphological criteria each. A third radiologist rated the MRI-cases as active/inactive, depending on the signal-intensities of lung tissues. Results: The pneumologist classified 14 patients into group A and 7 patients into group B. Using CT, 6 cases were classified as active, 15 cases as inactive disease. With MRI 12 cases were classified as active and 9 cases as inactive. In the complete group of 21 patients MRI decisions and CT decisions respectively were false positive/false negative/correct in 2/4/15 respectively 0/8/13 cases. Correct diagnoses were obtained in 72% (MRI) respectively 62% (CT). In the subgroup of 12 cases including HRCT, MRI respectively CT were false positive/false negative/correct in 2/1/9 respectively 0/5/7 cases. Correct diagnoses were obtained in 75% (MRI) respectively 58% (CT). Conclusion: Highfield MRI of the lung is feasible and performed slightly better compared to CT in the

  7. Comparison of the aerodynamics of bridge cables with helical fillets and a pattern-indented surface in normal flow

    DEFF Research Database (Denmark)

    Kleissl, Kenneth; Georgakis, Christos

    2011-01-01

    Over the last two decades, several bridge cable manufacturers have introduced surface modi-fications on the high-density polyethylene (HDPE) sheathing that is often installed for the protection of inner strands. The main goal of this is rain rivulet impedance, leading to the suppression of rain......-wind induced vibrations (RWIVs). The modifications are based on re-search undertaken predominantly in Europe and Japan, with two different systems prevailing; HDPE tubing fitted with helical surface fillets and HDPE tubing with pattern-indented sur-faces. In the US and Europe, helical fillets dominate, whilst...

  8. Usefulness of MR imaging for diseases of the small intestine: comparison with CT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Hoon; Ha, Hyun Kwon; Sohn, Min Jae; Shin, Byung Suck; Lee, Young Suk; Chung, Soo Yoon; Kim, Pyo Nyun; Lee, Moon Gyu; Auh, Yong Ho [Ulsan University College of Medicine, Seoul (Korea, Republic of)

    2000-03-01

    To evaluate the usefulness of MR imaging for diseases of the small intestine, emphasizing a comparison with CT. Thirty-four patients who underwent both CT and MR imaging using FLASH 2D and HASTE sequences were analyzed. All patients had various small bowel diseases with variable association of peritoneal lesions. We compared the detectabilities of CT and MR imaging using different MR pulse sequences. The capability for analyzing the characteristics of small intestinal disease was also compared. MR imaging was nearly equal to CT for detecting intraluminal or peritoneal masses, lesions in the bowel and mesentery, and small bowel obstruction, but was definitely inferior for detecting omental lesions. The most successful MR imaging sequence was HASTE for demonstrating bowel wall thickening, coronal FLASH 2D for mesenteric lesions, and axial FLASH 2D for omental lesions. MR imaging yielded greater information than CT in six of 12 inflammatory bowel diseases, while it was equal to CT in six of seven neoplasms and inferior in five of seven mesenteric ischemia. In determining the primary causes of 15 intestinal obstructions, MR imaging was correct in 11 (73%) and CT in nine (60%) patients. MR imaging can serve as an alternative diagnostic tool for patients with suspected inflammatory bowel disease, small intestinal neoplasm or obstruction.

  9. Comparison of three-dimensional helical axes of the cervical spine between in vitro and in vivo testing.

    Science.gov (United States)

    Jonas, René; Demmelmaier, Robert; Hacker, Steffen P; Wilke, Hans-Joachim

    2017-10-23

    The range of motion is a well-accepted parameter for the assessment and evaluation of cervical motion. However, more qualitative data of the kinematics of the cervical spine are needed for the development and success of cervical disc arthroplasty. The aim of this study was to provide basic information about helical axes of human cervical spine under in vitro conditions. Furthermore, it should clarify whether the three-dimensional helical axes of cervical motion gained from in vitro experiments are in agreement with those gained from in vivo experiments, and therefore to prove its reliability. An in vitro test with pure moments and mono-segmental specimens was designed to investigate and compare the helical axes of the cervical spine. Six human cadaveric specimens (three male and three female) with an average age of 47.5 years (range: 34-58 years) were carefully selected. Each specimen was divided into three motion segments: C2-C3, C4-C5, and C6-C7. We performed 3.5 full cycles of rotation about all axes, flexion-extension, lateral bending, and axial rotation, by applying pure moments of 1.5 Nm without any preload. Following the in vitro tests, the three-dimensional helical axes were calculated and projected into the x-ray images. Rotation analysis of all three directions revealed similar results for all six specimens. All calculated helical axes were similar to the published in vivo data. Furthermore, the instantaneous centers of rotation were in agreement with in vivo data. The data gained from this study verify cervical kinematics during in vitro testing using pure moments. It can be assumed that other soft tissue such as muscles are not necessarily needed to simulate cervical kinematics in vitro. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. "High-precision, reconstructed 3D model" of skull scanned by conebeam CT: Reproducibility verified using CAD/CAM data.

    Science.gov (United States)

    Katsumura, Seiko; Sato, Keita; Ikawa, Tomoko; Yamamura, Keiko; Ando, Eriko; Shigeta, Yuko; Ogawa, Takumi

    2016-01-01

    Computed tomography (CT) scanning has recently been introduced into forensic medicine and dentistry. However, the presence of metal restorations in the dentition can adversely affect the quality of three-dimensional reconstruction from CT scans. In this study, we aimed to evaluate the reproducibility of a "high-precision, reconstructed 3D model" obtained from a conebeam CT scan of dentition, a method that might be particularly helpful in forensic medicine. We took conebeam CT and helical CT images of three dry skulls marked with 47 measuring points; reconstructed three-dimensional images; and measured the distances between the points in the 3D images with a computer-aided design/computer-aided manufacturing (CAD/CAM) marker. We found that in comparison with the helical CT, conebeam CT is capable of reproducing measurements closer to those obtained from the actual samples. In conclusion, our study indicated that the image-reproduction from a conebeam CT scan was more accurate than that from a helical CT scan. Furthermore, the "high-precision reconstructed 3D model" facilitates reliable visualization of full-sized oral and maxillofacial regions in both helical and conebeam CT scans. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  11. Quantitative comparison of PET performance—Siemens Biograph mCT and mMR

    Energy Technology Data Exchange (ETDEWEB)

    Karlberg, Anna M.; Sæther, Oddbjørn [Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Olav Kyrres gt 17, 7006 Trondheim (Norway); Eikenes, Live [Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Postbox 8905, 7491 Trondheim (Norway); Goa, Pål Erik [Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Olav Kyrres gt 17, 7006 Trondheim (Norway); Department of Physics, Norwegian University of Science and Technology, Trondheim (Norway)

    2016-02-25

    Integrated clinical whole-body PET/MR systems were introduced in 2010. In order to bring this technology into clinical usage, it is of great importance to compare the performance with the well-established PET/CT. The aim of this study was to evaluate PET performance, with focus on image quality, on Siemens Biograph mMR (PET/MR) and Siemens Biograph mCT (PET/CT). A direct quantitative comparison of the performance characteristics between the mMR and mCT system was performed according to National Electrical Manufacturers Association (NEMA) NU 2-2007 protocol. Spatial resolution, sensitivity, count rate and image quality were evaluated. The evaluation was supplemented with additional standardized uptake value (SUV) measurements. The spatial resolution was similar for the two systems. Average sensitivity was higher for the mMR (13.3 kcps/MBq) compared to the mCT system (10.0 kcps/MBq). Peak noise equivalent count rate (NECR) was slightly higher for the mMR (196 kcps @ 24.4 kBq/mL) compared to the mCT (186 kcps @ 30.1 kBq/mL). Scatter fractions in the clinical activity concentration range yielded lower values for the mCT (34.9 %) compared to those for the mMR (37.0 %). Best image quality of the systems resulted in approximately the same mean hot sphere contrast and a difference of 19 percentage points (pp) in mean cold contrast, in favour of the mCT. In general, point spread function (PSF) increased hot contrast and time of flight (TOF) increased both hot and cold contrast. Highest hot contrast for the smallest sphere (10 mm) was achieved with the combination of TOF and PSF on the mCT. Lung residual error was higher for the mMR (22 %) than that for the mCT (17 %), with no effect of PSF. With TOF, lung residual error was reduced to 8 % (mCT). SUV was accurate for both systems, but PSF caused overestimations for the 13-, 17- and 22-mm spheres. Both systems proved good performance characteristics, and the PET image quality of the mMR was close to that of the mCT

  12. Assess PET/MR in diagnosis of disease in comparison with PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Jianhua; Lim, Jason Chu-Chern; Loi, Hoi Yin; Totoman, John [A*STAR-NUS Clinical Imaging Research Centre (Singapore); Sinha, Arvind Kumar; Quek, Swee Titan [Department of Diagnostic Imaging, National University Hospital (Singapore); Townsend, David [A*STAR-NUS Clinical Imaging Research Centre (Singapore)

    2015-05-18

    The aim of this study is to assess the performance of 18F-FDG whole body PET/MRI in comparison with PET/CT based on SUV. Anatomical location of lesion with Dixon MRI and additional value of advanced MRI technology such as diffusion weighted MR imaging in diagnosis of malignant disease will also be investigated.

  13. [Comparison study of CT indicators and pathological N staging in lymph node metastasis of gastric cancer].

    Science.gov (United States)

    Tang, Lei; Zhang, Xiao-peng; Sun, Ying-shi; Li, Jie; Wang, Ning; Cao, Kun; Ji, Jia-fu; Li, Zi-yu

    2008-11-01

    To explore the CT criteria for evaluating lymph node (LN) metastasis and preoperative N-staging of gastric cancer through the comparison of CT signs and surgical pathology. Eighty-nine patients with gastric cancer underwent CT examinations before radical resections. A soft-reading method on PACS workstation was employed to evaluate the detection of LNs. The size and number of LNs were registered, and the accumulated size of LNs was calculated in every case. The pathological N-staging (pN(0-3)) was considered on the basis of pathological examination of excised specimens according to UICC TNM-staging system (6th edition, 2002). The relationships between LN metastases and CT findings were analyzed by SPSS using t test and one-way ANOVA analysis. The distribution of maximal size, CT detection number and accumulated size were significantly different among different pN stages (P0.05), while significant difference could be found in CT detection number between pN1 and pN3 (P<0.01), pN2 and pN3 (P<0.01), and in accumulated size between pN1 and pN3 (P<0.01), pN1 and pN2 (P<0.01). The involvement of LNs in gastric cancer and pN staging are associated with size, number, and accumulated size of CT detection. CT detection number is more valuable in the evaluation of N staging than LNs size. CT detection number combined with accumulated size of LNs can provide meaningful information for preoperative N-staging.

  14. Percutaneous radiofrequency thermal ablation of lung VX2 tumors in a rabbit model: evaluation with helical CT findings for the complete and partal ablation

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Gong Yong; Han, Young Min; Lim, Yeong Su; Jang, Kyu Yun; Lee, Sang Yong; Chung, Gyung Ho [School of Medicine, Chonbuk National Univ., Chonju (Korea, Republic of)

    2004-05-01

    To evaluate the radiologic findings for complete and partial ablation after percutaneous CT-guided transthoracic radiofrequency ablation (RFA) of lung VX2 tumor implanted in rabbits. Thirteen rabbits with successfully implanted lung VX2 were used. Three rabbits as controls did not receive RFA while the other ten rabbits underwent RFA; 5 complete and 5 partial. RFA was performed using an internally cooled, 17-gauge electrode (Radionics, Burlington, MA) with a 1-cm active tip under CT guidance. Postprocedural CT was performed within 3 days, and we analyzed the ablated size, enhancement pattern, shape, margin, and complications of the complete and partial ablation groups. Rabbits were sacrificed after postprocedural CT with an overdose of ketamine, and pathologic findings of the ablated groups were compared with those of the control group. The size of the ablated lesions and the enhancement pattern differed between the completely and partially ablated groups on chest CT. The size of the ablated lesions was increased by 47.1% in the completely ablated group and by 2.1% in the partially ablated group. In the completely ablated group, VX2 tumor showed absolutely no enhancement, whereas only ablated pulmonary parenchyma outside VX2 showed mild enhancement on enhanced CT. In the partial ablated group, a part of VX2 became strongly enhanced on enhanced CT. On microscopic examination, the completely ablated group demonstrated that a viable tumor cell was not visible. In the partially ablated group, however, a viable tumor cell within the surrounding fibrous capsule on the peripheral area of the VX2 was observed. The important CT findings for evaluation of complete and partial RFA are the ablated size and enhancement pattern of the ablated lesion.

  15. Comparison between CT Net enhancement and PET/CT SUV for N staging of gastric cancer: A case series

    Directory of Open Access Journals (Sweden)

    Amato Antonio Stabile Ianora

    2017-09-01

    Conclusion: CT Net enhancement represents an accurate tool for N staging of gastric cancer and could be considered as the CT corresponding quantitative parameter of F-FDG PET/CT SUV. It could be applied in the clinical practice for differentiating reactive lymph nodes from metastatic ones improving accuracy and specificity of CT.

  16. Experimental comparison of empirical material decomposition methods for spectral CT.

    Science.gov (United States)

    Zimmerman, Kevin C; Schmidt, Taly Gilat

    2015-04-21

    Material composition can be estimated from spectral information acquired using photon counting x-ray detectors with pulse height analysis. Non-ideal effects in photon counting x-ray detectors such as charge-sharing, k-escape, and pulse-pileup distort the detected spectrum, which can cause material decomposition errors. This work compared the performance of two empirical decomposition methods: a neural network estimator and a linearized maximum likelihood estimator with correction (A-table method). The two investigated methods differ in how they model the nonlinear relationship between the spectral measurements and material decomposition estimates. The bias and standard deviation of material decomposition estimates were compared for the two methods, using both simulations and experiments with a photon-counting x-ray detector. Both the neural network and A-table methods demonstrated a similar performance for the simulated data. The neural network had lower standard deviation for nearly all thicknesses of the test materials in the collimated (low scatter) and uncollimated (higher scatter) experimental data. In the experimental study of Teflon thicknesses, non-ideal detector effects demonstrated a potential bias of 11-28%, which was reduced to 0.1-11% using the proposed empirical methods. Overall, the results demonstrated preliminary experimental feasibility of empirical material decomposition for spectral CT using photon-counting detectors.

  17. Comparison of CT-derived Ventilation Maps with Deposition Patterns of Inhaled Microspheres in Rats

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, Rick E.; Lamm, W. J.; Einstein, Daniel R.; Krueger, Melissa; Glenny, Robb W.; Corley, Richard A.

    2015-04-01

    Purpose: Computer models for inhalation toxicology and drug-aerosol delivery studies rely on ventilation pattern inputs for predictions of particle deposition and vapor uptake. However, changes in lung mechanics due to disease can impact airflow dynamics and model results. It has been demonstrated that non-invasive, in vivo, 4DCT imaging (3D imaging at multiple time points in the breathing cycle) can be used to map heterogeneities in ventilation patterns under healthy and disease conditions. The purpose of this study was to validate ventilation patterns measured from CT imaging by exposing the same rats to an aerosol of fluorescent microspheres (FMS) and examining particle deposition patterns using cryomicrotome imaging. Materials and Methods: Six male Sprague-Dawley rats were intratracheally instilled with elastase to a single lobe to induce a heterogeneous disease. After four weeks, rats were imaged over the breathing cycle by CT then immediately exposed to an aerosol of ~1µm FMS for ~5 minutes. After the exposure, the lungs were excised and prepared for cryomicrotome imaging, where a 3D image of FMS deposition was acquired using serial sectioning. Cryomicrotome images were spatially registered to match the live CT images to facilitate direct quantitative comparisons of FMS signal intensity with the CT-based ventilation maps. Results: Comparisons of fractional ventilation in contiguous, non-overlapping, 3D regions between CT-based ventilation maps and FMS images showed strong correlations in fractional ventilation (r=0.888, p<0.0001). Conclusion: We conclude that ventilation maps derived from CT imaging are predictive of the 1µm aerosol deposition used in ventilation-perfusion heterogeneity inhalation studies.

  18. Comparison of CT-derived ventilation maps with deposition patterns of inhaled microspheres in rats.

    Science.gov (United States)

    Jacob, Richard E; Lamm, Wayne J; Einstein, Daniel R; Krueger, Melissa A; Glenny, Robb W; Corley, Richard A

    2015-04-01

    Computer models for inhalation toxicology and drug-aerosol delivery studies rely on ventilation pattern inputs for predictions of particle deposition and vapor uptake. However, changes in lung mechanics due to disease can impact airflow dynamics and model results. It has been demonstrated that non-invasive, in vivo, 4DCT imaging (3D imaging at multiple time points in the breathing cycle) can be used to map heterogeneities in ventilation patterns under healthy and disease conditions. The purpose of this study was to validate ventilation patterns measured from CT imaging by exposing the same rats to an aerosol of fluorescent microspheres (FMS) and examining particle deposition patterns using cryomicrotome imaging. Six male Sprague-Dawley rats were intratracheally instilled with elastase to a single lobe to induce a heterogeneous disease. After four weeks, rats were imaged over the breathing cycle by CT then immediately exposed to an aerosol of ∼ 1 μm FMS for ∼ 5 minutes. After the exposure, the lungs were excised and prepared for cryomicrotome imaging, where a 3D image of FMS deposition was acquired using serial sectioning. Cryomicrotome images were spatially registered to match the live CT images to facilitate direct quantitative comparisons of FMS signal intensity with the CT-based ventilation maps. Comparisons of fractional ventilation in contiguous, non-overlapping, 3D regions between CT-based ventilation maps and FMS images showed strong correlations in fractional ventilation (r = 0.888, p ventilation maps derived from CT imaging are predictive of the 1 μm aerosol deposition used in ventilation-perfusion heterogeneity inhalation studies.

  19. Compression CT urography: a comparison with IVU in the opacification of the collecting system and ureters.

    Science.gov (United States)

    Heneghan, J P; Kim, D H; Leder, R A; DeLong, D; Nelson, R C

    2001-01-01

    The purpose of this study was to evaluate opacification of the collecting system and ureters using compression computed tomography (CT) urography compared with conventional intravenous urography (IVU). Fifty consecutive patients underwent compression CT urography as part of a dedicated renal CT. A compression belt was applied prior to nephrographic phase imaging. Excretory phase scans were acquired through the kidneys 3 minutes post injection with the compression belt in place. The compression belt was then released, and scans were obtained through the ureters. Three independent readers then scored opacification of the collecting system and ureters on a scale of 0-2 (0 = no opacification, 1 = partial opacification, 2 = full opacification and distension). Fifty consecutive nonmatched IVUs were scored by segment by the same readers. Comparison of the two modalities was made using the Mann-Whitney U test. Interobserver agreement was assessed by the Kappa coefficient. CT demonstrated significantly better opacification (p IVU. The Kappa coefficient was 0.53. Compression CT urography yields equal or better opacification of the collecting system and ureters when compared with IVU, and shows promise for the routine evaluation of the renal excretory system.

  20. Evaluation of a metal artifact reduction algorithm applied to post-interventional flat detector CT in comparison to pre-treatment CT in patients with acute subarachnoid haemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Mennecke, Angelika; Svergun, Stanislav; Doerfler, Arnd; Struffert, Tobias [University of Erlangen-Nuremberg, Department of Neuroradiology, Erlangen (Germany); Scholz, Bernhard [Siemens Healthcare GmbH, Forchheim (Germany); Royalty, Kevin [Siemens Medical Solutions, USA, Inc., Hoffman Estates, IL (United States)

    2017-01-15

    Metal artefacts can impair accurate diagnosis of haemorrhage using flat detector CT (FD-CT), especially after aneurysm coiling. Within this work we evaluate a prototype metal artefact reduction algorithm by comparison of the artefact-reduced and the non-artefact-reduced FD-CT images to pre-treatment FD-CT and multi-slice CT images. Twenty-five patients with acute aneurysmal subarachnoid haemorrhage (SAH) were selected retrospectively. FD-CT and multi-slice CT before endovascular treatment as well as FD-CT data sets after treatment were available for all patients. The algorithm was applied to post-treatment FD-CT. The effect of the algorithm was evaluated utilizing the pre-post concordance of a modified Fisher score, a subjective image quality assessment, the range of the Hounsfield units within three ROIs, and the pre-post slice-wise Pearson correlation. The pre-post concordance of the modified Fisher score, the subjective image quality, and the pre-post correlation of the ranges of the Hounsfield units were significantly higher for artefact-reduced than for non-artefact-reduced images. Within the metal-affected slices, the pre-post slice-wise Pearson correlation coefficient was higher for artefact-reduced than for non-artefact-reduced images. The overall diagnostic quality of the artefact-reduced images was improved and reached the level of the pre-interventional FD-CT images. The metal-unaffected parts of the image were not modified. (orig.)

  1. Introduction of an effective method for the optimization of CT protocols using iterative reconstruction algorithms: comparison with patient data

    National Research Council Canada - National Science Library

    Kordolaimi, Sofia D; Saradeas, Ioannis; Ploussi, Agapi; Pantos, Ioannis; Argentos, Stylianos; Efstathopoulos, Efstathios P

    2014-01-01

    The purpose of this study is to introduce an efficient method for the optimization of iterative reconstruction CT protocols based on phantom image analysis and the comparison of obtained results with actual patient data...

  2. Dose reduction for chest CT: comparison of two iterative reconstruction techniques.

    Science.gov (United States)

    Pourjabbar, Sarvenaz; Singh, Sarabjeet; Kulkarni, Naveen; Muse, Victorine; Digumarthy, Subba R; Khawaja, Ranish Deedar Ali; Padole, Atul; Do, Synho; Kalra, Mannudeep K

    2015-06-01

    Lowering radiation dose in computed tomography (CT) scan results in low quality noisy images. Iterative reconstruction techniques are used currently to lower image noise and improve the quality of images. To evaluate lesion detection and diagnostic acceptability of chest CT images acquired at CTDIvol of 1.8 mGy and processed with two different iterative reconstruction techniques. Twenty-two patients (mean age, 60 ± 14 years; men, 13; women, 9; body mass index, 27.4 ± 6.5 kg/m(2)) gave informed consent for acquisition of low dose (LD) series in addition to the standard dose (SD) chest CT on a 128 - multidetector CT (MDCT). LD images were reconstructed with SafeCT C4, L1, and L2 settings, and Safire S1, S2, and S3 settings. Three thoracic radiologists assessed LD image series (S1, S2, S3, C4, L1, and L2) for lesion detection and comparison of lesion margin, visibility of normal structures, and diagnostic confidence with SD chest CT. Inter-observer agreement (kappa) was calculated. Average CTDIvol was 6.4 ± 2.7 mGy and 1.8 ± 0.2 mGy for SD and LD series, respectively. No additional lesion was found in SD as compared to LD images. Visibility of ground-glass opacities and lesion margins, as well as normal structures visibility were not affected on LD. CT image visibility of major fissure and pericardium was not optimal in some cases (n = 5). Objective image noise in some low dose images processed with SafeCT and Safire was similar to SD images (P value > 0.5). Routine LD chest CT reconstructed with iterative reconstruction technique can provide similar diagnostic information in terms of lesion detection, margin, and diagnostic confidence as compared to SD, regardless of the iterative reconstruction settings. © The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  3. Diagnosis of acute flank pain caused by ureteral stones: value of combined direct and indirect signs on IVU and unenhanced helical CT.

    Science.gov (United States)

    Wang, Li-Jen; Ng, Chip-Jin; Chen, Jih-Chang; Chiu, Te-Fa; Wong, Yon-Cheong

    2004-09-01

    The aim of this study was to assess the usefulness of combined direct and indirect signs on intravenous urography (IVU) and unenhanced helical computed tomography (UHCT) for the diagnosis of ureteral stones in emergency patients with acute flank pain. During an 8-month period, 82 emergency patients with acute flank pain undergoing IVU and UHCT with sufficient clinical follow-up formed the study group. The presence or absence of direct sign (visualization of ureteral stones) and indirect signs on IVU and UHCT was recorded. The diagnostic accuracy of each direct/indirect sign and their combination for the diagnosis of ureteral stones on IVU and UHCT were analyzed and compared. Of the 82 patients, 66 had ureteral stones, four had passed urinary stones prior to imaging and 12 had other diseases. The diagnostic accuracies of direct signs on IVU and UHCT for the diagnosis of ureteral stones were 79.3 and 98.8%, respectively, which was more accurate than that of any single indirect sign on IVU and UHCT. However, the diagnostic accuracy of ureteral stones by IVU increased to 90.2% when using diagnostic criteria requiring the presence of a direct sign or at least three indirect signs, and by UHCT, it increased to 100% when using diagnostic criteria requiring the presence of a direct sign with at least one indirect sign. Therefore, for emergency patients with acute flank pain, the use of the above combinations of direct/indirect signs is useful as the diagnostic criterion for ureteral stones.

  4. CT gel dosimetry technique: comparison of a planned and measured 3D stereotactic dose volume.

    Science.gov (United States)

    Audet, C; Hilts, M; Jirasek, A; Duzenli, C

    2002-01-01

    This study presents a 3D dose mapping of complex dose distributions using an x-ray computed tomography (CT) polymer gel dosimetry technique. Two polyacrylamide gels (PAGs) of identical composition were irradiated with the same four arc stereotactic treatment to maximum doses of 15 Gy (PAG1) and 8 Gy (PAG2). The PAGs were CT imaged using a previously defined protocol that involves image averaging and background subtraction to improve image quality. For comparison with the planned isodose distribution, the PAG images were converted to relative dose maps using a CT number-dose calibration curve or simple division. The PAG images were then co-registered with the planning CT images in the BrainLab treatment planning software which automatically provides reconstructed sagittal and coronal images for 3D evaluation of measured and planned dose. The hypo-intense high dose region in both sets of gel images agreed with the planned 80% isodose contour and was shifted by up to 1.5 and 3.0 mm in the axial and reconstructed planes, respectively. This demonstrates the ability of the CT gel technique to accurately localize the high dose region produced by the stereotactic treatment. The resulting agreement of the measured relative dose volume for PAG1 was within 3.0 mm for the 50% and 80% isodose surfaces. However, the dose contrast was too low in PAG2 to allow for accurate definition of measured relative dose surfaces. Thus, a PAG should be irradiated to higher doses if quantitative relative dose information is required. Unfortunately, this implies use of an additional PAG and its CT number dose response since doses greater than 8-10 Gy fall outside the linear regions of the response.

  5. 4D-CT-based target volume definition in stereotactic radiotherapy of lung tumours: comparison with a conventional technique using individual margins.

    Science.gov (United States)

    Hof, Holger; Rhein, Bernhard; Haering, Peter; Kopp-Schneider, Annette; Debus, Jürgen; Herfarth, Klaus

    2009-12-01

    To investigate the dosimetric benefit of integration of 4D-CT in the planning target volume (PTV) definition process compared to conventional PTV definition using individual margins in stereotactic body radiotherapy (SBRT) of lung tumours. Two different PTVs were defined: PTV(conv) consisting of the helical-CT-based clinical target volume (CTV) enlarged isotropically for each spatial direction by the individually measured amount of motion in the 4D-CT, and PTV(4D) encompassing the CTVs defined in the 4D-CT phases displaying the extremes of the tumour position. Tumour motion as well as volumetric and dosimetric differences and relations of both PTVs were evaluated. Volumetric examinations revealed a significant reduction of the mean PTV by 4D-CT from 57.7 to 40.7 cm(3) (31%) (pindividual margins for target volume definition cannot compensate for the additional effects that the implementation of 4D-CT phases can offer.

  6. Accuracy of low dose CT in the diagnosis of appendicitis in childhood and comparison with USG and standard dose CT.

    Science.gov (United States)

    Yi, Dae Yong; Lee, Kyung Hoon; Park, Sung Bin; Kim, Jee Taek; Lee, Na Mi; Kim, Hyery; Yun, Sin Weon; Chae, Soo Ahn; Lim, In Seok

    Computed tomography should be performed after careful consideration due to radiation hazard, which is why interest in low dose CT has increased recently in acute appendicitis. Previous studies have been performed in adult and adolescents populations, but no studies have reported on the efficacy of using low-dose CT in children younger than 10 years. Patients (n=475) younger than 10 years who were examined for acute appendicitis were recruited. Subjects were divided into three groups according to the examinations performed: low-dose CT, ultrasonography, and standard-dose CT. Subjects were categorized according to age and body mass index (BMI). Low-dose CT was a contributive tool in diagnosing appendicitis, and it was an adequate method, when compared with ultrasonography and standard-dose CT in terms of sensitivity (95.5% vs. 95.0% and 94.5%, p=0.794), specificity (94.9% vs. 80.0% and 98.8%, p=0.024), positive-predictive value (96.4% vs. 92.7% and 97.2%, p=0.019), and negative-predictive value (93.7% vs. 85.7% and 91.3%, p=0.890). Low-dose CT accurately diagnosed patients with a perforated appendix. Acute appendicitis was effectively diagnosed using low-dose CT in both early and middle childhood. BMI did not influence the accuracy of detecting acute appendicitis on low-dose CT. Low-dose CT is effective and accurate for diagnosing acute appendicitis in childhood, as well as in adolescents and young adults. Additionally, low-dose CT was relatively accurate, irrespective of age or BMI, for detecting acute appendicitis. Therefore, low-dose CT is recommended for assessing children with suspected acute appendicitis. Copyright © 2017. Published by Elsevier Editora Ltda.

  7. Transcatheter arterial embolization therapy for a hypoplastic pelvic kidney with a single vaginal ectopic ureter to control incontinence: the usefulness of three-dimensional CT angiography using multidetector-row helical CT.

    Science.gov (United States)

    Kudoh, Kouichi; Kadota, Masataka; Nakayama, Yoshiharu; Imuta, Masanori; Yasuda, Tsuyoshi; Yamashita, Yasuyuki; Inadome, Akito; Yoshida, Masaki; Ueda, Shouichi

    2003-01-01

    A girl with continuous urinary incontinence was successfully treated by angiographic embolization of a hypoplastic pelvic kidney with a single unilateral vaginal ectopic opening of the ureter. For this intervention, CT angiography was useful for detecting the corresponding renal artery of the hypoplastic kidney.

  8. The role of 3D Helical CT in the reconstructive treatment of maxillofacial cancers; Tomografia Computerizzata spirale con elaborazioni tridimensionali di superficie nel trattamento ricostruttivo dei tumori maligni del massiccio facciale

    Energy Technology Data Exchange (ETDEWEB)

    De Rosa, V.; Ziviello, M. [Ospedale Cardarelli, Servizio di Radiodiagnostica, Naples (Italy); Ionna, F.; Mozzillo, N. [Ospedale Cardarelli, Div. di Chirurgia B, Ist. Nazionale Tumori Fondazione G. Pascale, Naples (Italy); Parascandolo, S. [Ospedale Cardarelli, Div. di Chirurgia Maxillo-Facciale, Naples (Italy)

    2000-12-01

    Purpose of this work is to investigate the role of Helical CT and the usefulness of three-dimensional (3D) imaging for pre-operative planning and follow-up of reconstructive maxillofacial surgery with alloplastic material in neoplastic disease involving this region. From 1996 to 1999 eleven patients were examined with Helical CT and 3D images for planning of maxillofacial plastic and reconstructive surgery for advanced cancer of this anatomically complex region. A 3D-modulated titanium mesh (100%) or micronets was used to rebuild the anterior surface of maxillary bone and the orbital floor. The mesh was cut to the appropriate size and shape and curved where necessary. Within the residual sinusal cavity a siliconed filling was used surmounting an acrylic prosthesis with dental arch to rebuild the palate. A rehydrated bovine pericardium was affixed and moduled on the borders in two cases only. Three-dimensionally reconstructed CT images were obtained preoperatively and at least 6 months postoperatively in all patients. The images were generated on a computer workstation using the shaded surface display (SSD) software with threshold values ranging 425 to 630 HU, and a more closed window for the imaging of titanium mesh/bone interface in the post surgical follow-up. It was obtained an excellent complete spatial depiction of maxillo facial region both before and after surgery, with no artefacts so important as to affect the 3D reconstruction process and the image quality. Together with the head-neck surgical team it could be worked for preoperative planning through CT scans by different 3D points of view. The 3D reconstructed follow-up scans showed good filling of the defect in the area where the titanium mesh had been used. Then efficacious bone modelling and good biocompatibility of the alloplastic material were seen in all patients, with no inflammatory reactions. Titanium is a well-known material, which is widely used for cranioplasty. It is a radiolucent, non

  9. Comparison of characteristic CT findings of lymphedema, cellulitis, and generalized edema in lower leg swelling.

    Science.gov (United States)

    Shin, Sung Ui; Lee, Whal; Park, Eun-Ah; Shin, Cheong-Il; Chung, Jin Wook; Park, Jae Hyung

    2013-12-01

    To determine the different computed tomography (CT) findings of lymphedema, cellulitis, and generalized edema in the lower leg. CT images of 44 patients with confirmed lymphedema (n = 19), cellulitis (n = 11), or generalized edema (n = 14) were retrospectively reviewed. The following characteristics were evaluated: extent of edema, laterality, skin thickening, honeycombing, taller than wide appearance, muscle edema, conglomeration of septum of fat lobule, fluid collection, fascial enhancement, inguinal lymph node (LN) enlargement, medullary fat obliteration of inguinal LN, trunk subcutaneous edema, and bone marrow edema. Fisher's exact test with Bonferroni correction was used for multiple comparisons. Honeycombing and taller than wide appearance of fat lobules were more common in lymphedema (P edema of the trunk were more common in generalized edema (P edema and bone marrow edema were specific findings of generalized edema.

  10. A strategy to optimize radiation exposure for non-contrast head CT: comparison with the Japanese diagnostic reference levels.

    Science.gov (United States)

    Kumamaru, Kanako K; Kogure, Yosuke; Suzuki, Michimasa; Hori, Masaaki; Nakanishi, Atsushi; Kamagata, Koji; Hagiwara, Akifumi; Andica, Christina; Ri, Keiken; Houshido, Naoyoshi; Aoki, Shigeki

    2016-06-01

    To describe how we performed a protocol review, analyzed data, identified opportunities to reduce radiation exposure, and then implemented a new imaging protocol for non-contrast adult head CT at our institution with reduced radiation exposure, using the Japanese diagnostic reference levels (DRLs) as the reference. After analyzing the CT dose index (CTDIvol) and dose length product (DLP) in all non-contrast adult head CT examinations performed during a 3-month period (September to November 2015) in order to identify a specific protocol that contributed to the above-DRL-level radiation exposure observed for non-contrast adult head CT at our institution, phantom studies with objective and subjective image quality analyses were performed to develop a new imaging protocol. After implementing the new protocol, its feasibility was evaluated in terms of radiation exposure, prevalence of significant disease detection, and subjective image quality. The review of 2040 examinations revealed that a helical protocol (CTDIvol = 93.4 mGy) with one of four CT scanners mainly contributed to the above-DRL-level radiation exposure (mean DLP at this scanner = 1401.2 mGy cm) in non-contrast adult head CT at our institution. To replace this protocol, the phantom study identified a wide-volume scan using 120 kVp, 350 mAs, a 4-cm detector, a slice thickness of 5 mm, and a CTDIvol of 69.8 mGy as a new protocol that yielded comparable image quality to the existing protocol. After the implementation of the new protocol, the overall mean DLP reduced to 1365 mGy cm without any apparent degradation of image quality. No significant decrease in the prevalence of significant findings after protocol revision was noted. We report the successful implementation of a new protocol with reduced radiation exposure for non-contrast head CT examinations.

  11. Comparison of the 68Ga-DOTATATA PET/CT, FDG PET/CT, and MIBG SPECT/CT in the Evaluation of Suspected Primary Pheochromocytomas and Paragangliomas.

    Science.gov (United States)

    Jing, Hongli; Li, Fang; Wang, Ling; Wang, Zhenghua; Li, Wei; Huo, Li; Zhang, Jingjing

    2017-07-01

    Anatomical imaging modalities including CT and MRI are the mainstay of evaluation of primary pheochromocytoma or paraganglioma. However, nuclear medicine imaging is frequently necessary to determine the nature of the lesions. The purpose of this investigation is to assess which commonly used nuclear medicine modality might have a better diagnostic value in this clinical setting. Eight patients who had been suspected of having either primary pheochromocytoma or primary paraganglioma and 1 patient with known pheochromocytoma were included in the analysis. Among the 8 patients without known diagnosis, 7 had been suggested by anatomical imaging modalities, whereas one of them presented with initial negative anatomical imaging interpretation. All of 9 patients underwent Ga-DOTATATA PET/CT, FDG PET/CT, and MIBG SPECT/CT for further evaluation. The imaging findings were compared with postsurgical pathology and follow-up. Both Ga-DOTATATA PET/CT and MIBG SPECT/CT accurately identified 9 primary tumors, whereas FDG PET/CT showed increased activity in 8 of 9 primary tumors. Both Ga-DOTATATA and FDG PET/CT are able to detect associated extra-adrenal lesions not shown on MIBG study in patients with multiple endocrine neoplasia syndrome. Ga-DOTATATA PET/CT could be the nuclear medicine imaging choice to evaluate suspected primary pheochromocytoma or paraganglioma, especially in the situation of multiple endocrine neoplasia syndrome.

  12. Interobserver variability in visual evaluation of thoracic CT scans and comparison with automatic computer measurements of CT lung density

    DEFF Research Database (Denmark)

    Winkler Wille, Mathilde Marie; Thomsen, Laura Hohwü; Dirksen, Asger

    2012-01-01

    lung density measurements, i.e. densitometry. Methods – In a pilot study 60 CT scans were selected from a sample of 3980 CT scans from The Danish Lung Cancer Screening Trial (DLCST). The amount of emphysema in these scans was scored independently by two observers, who were blinded regarding clinical...

  13. Comparison between CT and MRI in the assessment of pulmonary embolism: A meta-analysis.

    Science.gov (United States)

    Chen, Feng; Shen, Yi-Hong; Zhu, Xu-Qing; Zheng, Jing; Wu, Feng-Jie

    2017-12-01

    Besides pulmonary arteriography, a number of imaging techniques, such as magnetic resonance imaging (MRI) and computed tomography (CT), were adopted in the detection of identifying pulmonary embolism (PE). However, the contrast of sensitivity and specificity in these methods was studied little in a statistical way. To compare the effects of MRI and CT, this study used a series of methods to analyze data in included researches. A comprehensive computer search was conducted through internet up to July 2016. The quality assessment was performed by the Quality Assessment Tool for Diagnostic Accuracy Studies, version 2 tool. The diagnostic value of comparison between MRI and CT was evaluated by using the pooled estimate of sensitivity, specificity, and summary receiver operating characteristic (SROC) curve. In addition, sensitivity analysis and bias analysis were applied to ensure the accuracy of the results. Ten studies with 590 cases were involved in the study. Only 2 trials had high risk regarding bias while other trials were supposed to be at low risk of applicability. Heterogeneity existed in analysis of both CT and MRI. The pooled sensitivity of CT was 0.90 (95% CI: 0.85-0.93), pooled specificity was 0.88 (95% CI: 0.77 to 0.95), the pooled sensitivity of MRI was 0.92 (95% CI: 0.89-0.94), and pooled specificity was 0.91 (95% CI: 0.77-0.97). The Q index of sensitivity and specificity for CT and MRI were 71.38, 19.67, 47.14, and 12.35, respectively. The SROC curve area under the curve of CT and MRI were 0.94 (95% CI: 0.91-0.96) and 0.93 (95% CI: 0.91-0.95), respectively. This meta-analysis demonstrates that MRI has better sensitivity and specificity in detecting subsegmental artery PE. MRI is a relatively better detection technique for PE. This conclusion is consistent with many published researches. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

  14. Flow-driven rotor simulation of vertical axis tidal turbines: A comparison of helical and straight blades

    Directory of Open Access Journals (Sweden)

    Tuyen Quang Le

    2014-06-01

    Full Text Available In this study, flow-driven rotor simulations with a given load are conducted to analyze the operational characteristics of a vertical-axis Darrieus turbine, specifically its self-starting capability and fluctuations in its torque as well as the RPM. These characteristics are typically observed in experiments, though they cannot be acquired in simulations with a given tip speed ratio (TSR. First, it is shown that a flow-driven rotor simulation with a two-dimensional (2D turbine model obtains power coefficients with curves similar to those obtained in a simulation with a given TSR. 3D flow-driven rotor simulations with an optimal geometry then show that a helical-bladed turbine has the following prominent advantages over a straight-bladed turbine of the same size: an improvement of its self-starting capabilities and reduced fluctuations in its torque and RPM curves as well as an increase in its power coefficient from 33% to 42%. Therefore, it is clear that a flow-driven rotor simulation provides more information for the design of a Darrieus turbine than a simulation with a given TSR before experiments.

  15. Flow-driven rotor simulation of vertical axis tidal turbines: A comparison of helical and straight blades

    Directory of Open Access Journals (Sweden)

    Le Tuyen Quang

    2014-06-01

    Full Text Available In this study, flow-driven rotor simulations with a given load are conducted to analyze the operational characteristics of a vertical-axis Darrieus turbine, specifically its self-starting capability and fluctuations in its torque as well as the RPM. These characteristics are typically observed in experiments, though they cannot be acquired in simulations with a given tip speed ratio (TSR. First, it is shown that a flow-driven rotor simulation with a two-dimensional (2D turbine model obtains power coefficients with curves similar to those obtained in a simulation with a given TSR. 3D flowdriven rotor simulations with an optimal geometry then show that a helical-bladed turbine has the following prominent advantages over a straight-bladed turbine of the same size: an improvement of its self-starting capabilities and reduced fluctuations in its torque and RPM curves as well as an increase in its power coefficient from 33% to 42%. Therefore, it is clear that a flow-driven rotor simulation provides more information for the design of a Darrieus turbine than a simulation with a given TSR before experiments.

  16. Finite helical axis for the analysis of joint kinematics: comparison of an electromagnetic and an optical motion capture system.

    Science.gov (United States)

    Cescon, Corrado; Tettamanti, Andrea; Barbero, Marco; Gatti, Roberto

    2015-01-01

    The analysis of joints kinematics is important in clinical practice and in research. Nowadays it is possible to evaluate the mobility of joints in vivo with different motion capture techniques available in the market. Optical systems use infrared cameras and reflective markers to evaluate body movements, while other systems use electromagnetic fields to detect position and orientation of sensors. The aim of this study was the evaluation of two motion capture systems based on different technologies (optical and electromagnetic) by comparing the distribution of finite helical axis (FHA) of rotation during controlled rotations of an object in different positions. The distribution of position and angle errors of the FHA were extracted by optical and electromagnetic system recordings during a controlled rotation of a low friction stool in different positions in a controlled environment. The optical motion capture system showed lower angle and position errors in the distribution of FHA while the electromagnetic system had higher errors that increased with increasing distance from the antenna. The optical system showed lower errors in the estimation of FHA that could make it preferable with respect to electromagnetic systems during joint kinematics.

  17. Cascades in helical turbulence

    CERN Document Server

    Ditlevsen, P D

    2001-01-01

    The existence of a second quadratic inviscid invariant, the helicity, in a turbulent flow leads to coexisting cascades of energy and helicity. An equivalent of the four-fifth law for the longitudinal third order structure function, which is derived from energy conservation, is easily derived from helicity conservation cite{Procaccia,russian}. The ratio of dissipation of helicity to dissipation of energy is proportional to the wave-number leading to a different Kolmogorov scale for helicity than for energy. The Kolmogorov scale for helicity is always larger than the Kolmogorov scale for energy so in the high Reynolds number limit the flow will always be helicity free in the small scales, much in the same way as the flow will be isotropic and homogeneous in the small scales. A consequence is that a pure helicity cascade is not possible. The idea is illustrated in a shell model of turbulence.

  18. Volumetric Assessment of Swallowing Muscles: A Comparison of CT and MRI Segmentation.

    Science.gov (United States)

    Sporns, Kim Barbara; Hanning, Uta; Schmidt, Rene; Muhle, Paul; Wirth, Rainer; Zimmer, Sebastian; Dziewas, Rainer; Suntrup-Krueger, Sonja; Sporns, Peter Bernhard; Heindel, Walter; Schwindt, Wolfram

    2017-11-03

    .075). Conclusion CT-based segmentation and MRI-based segmentation of the digastric and geniohyoid muscle are equally feasible. The potential advantage of MRI for prospective studies is the absence of ionizing radiation. Key Points  · CT-based segmentation and MRI-based segmentation of the swallowing muscles are equally feasible.. · The advantage of MRI is the absence of ionizing radiation.. · MRI should therefore be deployed for future prospective studies.. Citation Format · Sporns KB, Hanning U, Schmidt R et al. Volumetric Assessment of Swallowing Muscles: A Comparison of CT and MRI Segmentation. Fortschr Röntgenstr 2017; DOI: 10.1055/s-0043-120529. © Georg Thieme Verlag KG Stuttgart · New York.

  19. The role of ultrasonography in the imaging of body packers comparison with CT: a prospective study.

    Science.gov (United States)

    Cengel, Ferhat; Bulakci, Mesut; Selcuk, Tuba; Savas, Yildiray; Ceyhan, Muhammet; Kocak, Ayhan; Bilgili, Cigdem Ozkara

    2015-10-01

    This study investigated the sonographic properties of drug packets containing narcotic drugs and the diagnostic role of ultrasonography in detecting body packing in comparison with CT. Forty-five suspects admitted to our hospital for diagnosis and management were routinely evaluated by non-contrast CT for the presence of drug packets. A single radiologist blind to CT data independently performed the abdominal ultrasonographic scans. Thirty-five of 45 suspects were carrying packets. In positive cases, two types of packets with different properties were noted. Twenty-eight cases had type 1 packets (solid form drug) and 7 had type 2 packets (liquid form cocaine). The sensitivity, specificity, positive, and negative predictive values of ultrasonography for detecting drug packets were 91%, 70%, 91%, and 70%, respectively. Ultrasonography accurately determined the presence or absence of packs in 39 of 45 suspects. Ultrasonography was found to have a high sensitivity but a low specificity in suspected cases. A negative ultrasonography cannot rule out the diagnosis of body packing. However, it may be preferred as the initial imaging method or for follow-up of suspected cases as a radiation-free, easy-to-use, and inexpensive technique.

  20. CT of the chest with model-based, fully iterative reconstruction: comparison with adaptive statistical iterative reconstruction.

    Science.gov (United States)

    Ichikawa, Yasutaka; Kitagawa, Kakuya; Nagasawa, Naoki; Murashima, Shuichi; Sakuma, Hajime

    2013-08-09

    The recently developed model-based iterative reconstruction (MBIR) enables significant reduction of image noise and artifacts, compared with adaptive statistical iterative reconstruction (ASIR) and filtered back projection (FBP). The purpose of this study was to evaluate lesion detectability of low-dose chest computed tomography (CT) with MBIR in comparison with ASIR and FBP. Chest CT was acquired with 64-slice CT (Discovery CT750HD) with standard-dose (5.7 ± 2.3 mSv) and low-dose (1.6 ± 0.8 mSv) conditions in 55 patients (aged 72 ± 7 years) who were suspected of lung disease on chest radiograms. Low-dose CT images were reconstructed with MBIR, ASIR 50% and FBP, and standard-dose CT images were reconstructed with FBP, using a reconstructed slice thickness of 0.625 mm. Two observers evaluated the image quality of abnormal lung and mediastinal structures on a 5-point scale (Score 5 = excellent and score 1 = non-diagnostic). The objective image noise was also measured as the standard deviation of CT intensity in the descending aorta. The image quality score of enlarged mediastinal lymph nodes on low-dose MBIR CT (4.7 ± 0.5) was significantly improved in comparison with low-dose FBP and ASIR CT (3.0 ± 0.5, p = 0.004; 4.0 ± 0.5, p = 0.02, respectively), and was nearly identical to the score of standard-dose FBP image (4.8 ± 0.4, p = 0.66). Concerning decreased lung attenuation (bulla, emphysema, or cyst), the image quality score on low-dose MBIR CT (4.9 ± 0.2) was slightly better compared to low-dose FBP and ASIR CT (4.5 ± 0.6, p = 0.01; 4.6 ± 0.5, p = 0.01, respectively). There were no significant differences in image quality scores of visualization of consolidation or mass, ground-glass attenuation, or reticular opacity among low- and standard-dose CT series. Image noise with low-dose MBIR CT (11.6 ± 1.0 Hounsfield units (HU)) were significantly lower than with low-dose ASIR (21.1 ± 2.6 HU, p ASIR for providing diagnostically acceptable low-dose CT without

  1. Interobserver variability in visual evaluation of thoracic CT scans and comparison with automatic computer measurements of CT lung density

    DEFF Research Database (Denmark)

    Winkler Wille, Mathilde Marie; Thomsen, Laura Hohwü; Dirksen, Asger

    2012-01-01

    Introduction – Emphysema is defined by pathology, but is most precisely evaluated in vivo by computed tomography (CT). Aims – were to determine the reproducibility of visual evaluation of emphysema, i.e. the observer variability, and furthermore to compare the visual evaluations to automatic CT...... lung density measurements, i.e. densitometry. Methods – In a pilot study 60 CT scans were selected from a sample of 3980 CT scans from The Danish Lung Cancer Screening Trial (DLCST). The amount of emphysema in these scans was scored independently by two observers, who were blinded regarding clinical...... information. The lung was segmented automatically by in-house developed computer software, and the percentage of pixels below -950 HU was used as a surrogate marker for emphysema. The observer variability, as well as the correlation with the lung density measurements, was analysed using Spearman’s rank...

  2. Coronary calcium screening with dual-source CT: reliability of ungated, high-pitch chest CT in comparison with dedicated calcium-scoring CT

    Energy Technology Data Exchange (ETDEWEB)

    Hutt, Antoine; Faivre, Jean-Baptiste; Remy, Jacques; Remy-Jardin, Martine [CHRU et Universite de Lille, Department of Thoracic Imaging, Hospital Calmette (EA 2694), Lille (France); Duhamel, Alain; Deken, Valerie [CHRU et Universite de Lille, Department of Biostatistics (EA 2694), Lille (France); Molinari, Francesco [Centre Hospitalier General de Tourcoing, Department of Radiology, Tourcoing (France)

    2016-06-15

    To investigate the reliability of ungated, high-pitch dual-source CT for coronary artery calcium (CAC) screening. One hundred and eighty-five smokers underwent a dual-source CT examination with acquisition of two sets of images during the same session: (a) ungated, high-pitch and high-temporal resolution acquisition over the entire thorax (i.e., chest CT); (b) prospectively ECG-triggered acquisition over the cardiac cavities (i.e., cardiac CT). Sensitivity and specificity of chest CT for detecting positive CAC scores were 96.4 % and 100 %, respectively. There was excellent inter-technique agreement for determining the quantitative CAC score (ICC = 0.986). The mean difference between the two techniques was 11.27, representing 1.81 % of the average of the two techniques. The inter-technique agreement for categorizing patients into the four ranks of severity was excellent (weighted kappa = 0.95; 95 % CI 0.93-0.98). The inter-technique differences for quantitative CAC scores did not correlate with BMI (r = 0.05, p = 0.575) or heart rate (r = -0.06, p = 0.95); 87.2 % of them were explained by differences at the level of the right coronary artery (RCA: 0.8718; LAD: 0.1008; LCx: 0.0139; LM: 0.0136). Ungated, high-pitch dual-source CT is a reliable imaging mode for CAC screening in the conditions of routine chest CT examinations. (orig.)

  3. Superior labral anterior-to-posterior lesions: comparison of external rotation and active supination CT arthrography with neutral CT arthrography.

    Science.gov (United States)

    Choi, Ja-Young; Kim, Sae Hoon; Yoo, Hye Jin; Shin, Seung Han; Oh, Joo Han; Baek, Goo Hyun; Hong, Sung Hwan

    2012-04-01

    To compare the diagnostic performance of computed tomographic (CT) arthrography performed with external rotation and active supination (ERAS) with that of CT angiography performed in the neutral position for superior labral anterior-to-posterior (SLAP) lesions. Institutional review board approval and informed consent were obtained. CT arthrography in neutral and ERAS positions was performed in 49 shoulders of 47 patients, with subsequent arthroscopic confirmation of the status of the superior labrum. Two musculoskeletal radiologists (1 and 8 years of experience) reviewed images and expressed the likelihood of SLAP lesions by using a continuous scale; they also measured gap widths and depths of labral detachment. Overall performances for the detection of SLAP lesions were determined with receiver-operating characteristic (ROC) analysis. Gap widths and depths measured with the two types of CT arthrography were also compared. For reader 1, area under the ROC curve increased insignificantly from 0.932 in the neutral position to 0.974 in the ERAS position (P = .210), whereas for reader 2, it increased significantly from 0.914 to 0.984 (P = .032). Mean gap width of SLAP lesion was significantly greater according to ERAS CT arthrography (3.98 mm ± 2.48 [standard deviation] vs 1.61 mm ± 1.11), whereas mean gap depth was not significantly different. Gap width and depth cutoff values for the detection of a SLAP lesion with ERAS CT arthrography were 1.7 mm and 1.6 mm, respectively. ERAS CT arthrography might improve the detection of SLAP lesions compared with neutral-position CT arthrography. © RSNA, 2012.

  4. Comparison of CT and MRI in patients with tibial plateau fracture: can CT findings predict ligament tear or meniscal injury?

    Energy Technology Data Exchange (ETDEWEB)

    Mui, Leonora W.; Engelsohn, Eliyahu; Umans, Hilary [Jacobi Medical Center, Albert Einstein College of Medicine, Department of Radiology, Bronx, NY (United States)

    2007-02-15

    (1) To determine the accuracy of computed tomography (CT) in the evaluation of ligament tear and avulsion in patients with tibial plateau fracture. (2) To evaluate whether the presence or severity of fracture gap and articular depression can predict meniscal injury. A fellowship-trained musculoskeletal radiologist retrospectively reviewed knee CT and MRI examinations of 41 consecutive patients presenting to a level 1 trauma center with tibial plateau fractures. Fracture gap, articular depression, ligament tear and footprint avulsions were assessed on CT examinations. The MRI studies were examined for osseous and soft tissue injuries, including meniscal tear, meniscal displacement, ligament tear, and ligament avulsion. CT demonstrated torn ligaments with 80% sensitivity and 98% specificity. Only 2% of ligaments deemed intact on careful CT evaluation had partial or complete tears on MRI. Although the degree of fracture gap and articular depression was significantly greater in patients with meniscal injury compared with those without meniscal injury, ROC analysis demonstrated no clear threshold for gap or depression that yielded a combination of high sensitivity and specificity. In the acute setting, CT offers high sensitivity and specificity for depicting osseous avulsions, as well as high negative predictive value for excluding ligament injury. However, MRI remains necessary for the preoperative detection of meniscal injury. (orig.)

  5. A Clinical and Experimental Comparison of Time of Flight PET/MRI and PET/CT Systems

    OpenAIRE

    Oprea-Lager, Daniela E.; Yaqub, Maqsood; Pieters, Indra C; Reinhard, Rinze; van Moorselaar, Reindert J. A.; van den Eertwegh, Alfons J. M.; Hoekstra, Otto S; Lammertsma, Adriaan A; Boellaard, Ronald

    2015-01-01

    Purpose The purpose of the study was to compare image quality and quantitative accuracy of positron emission tomography/magnetic resonance imaging (PET/MRI) and PET/computed tomography (PET/CT) systems with time of flight PET gantries, using phantom and clinical studies. Procedures Identical phantom experiments were performed on both systems. Calibration, uniformity, and standardized uptake value (SUV) recovery were measured. A clinical PET/CT versus PET/MRI comparison was performed using [18...

  6. Inter-algorithm lesion volumetry comparison of real and 3D simulated lung lesions in CT

    Science.gov (United States)

    Robins, Marthony; Solomon, Justin; Hoye, Jocelyn; Smith, Taylor; Ebner, Lukas; Samei, Ehsan

    2017-03-01

    The purpose of this study was to establish volumetric exchangeability between real and computational lung lesions in CT. We compared the overall relative volume estimation performance of segmentation tools when used to measure real lesions in actual patient CT images and computational lesions virtually inserted into the same patient images (i.e., hybrid datasets). Pathologically confirmed malignancies from 30 thoracic patient cases from Reference Image Database to Evaluate Therapy Response (RIDER) were modeled and used as the basis for the comparison. Lesions included isolated nodules as well as those attached to the pleura or other lung structures. Patient images were acquired using a 16 detector row or 64 detector row CT scanner (Lightspeed 16 or VCT; GE Healthcare). Scans were acquired using standard chest protocols during a single breath-hold. Virtual 3D lesion models based on real lesions were developed in Duke Lesion Tool (Duke University), and inserted using a validated image-domain insertion program. Nodule volumes were estimated using multiple commercial segmentation tools (iNtuition, TeraRecon, Inc., Syngo.via, Siemens Healthcare, and IntelliSpace, Philips Healthcare). Consensus based volume comparison showed consistent trends in volume measurement between real and virtual lesions across all software. The average percent bias (+/- standard error) shows -9.2+/-3.2% for real lesions versus -6.7+/-1.2% for virtual lesions with tool A, 3.9+/-2.5% and 5.0+/-0.9% for tool B, and 5.3+/-2.3% and 1.8+/-0.8% for tool C, respectively. Virtual lesion volumes were statistically similar to those of real lesions (.05 in most cases. Results suggest that hybrid datasets had similar inter-algorithm variability compared to real datasets.

  7. Comparison of four software packages for CT lung volumetry in healthy individuals

    Energy Technology Data Exchange (ETDEWEB)

    Nemec, Stefan F. [Harvard Medical School, Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA (United States); Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria); Molinari, Francesco [Centre Hospitalier Regional Universitaire de Lille, Department of Radiology, Lille (France); Dufresne, Valerie [CHU de Charleroi - Hopital Vesale, Pneumologie, Montigny-le-Tilleul (Belgium); Gosset, Natacha [CHU Tivoli, Service d' Imagerie Medicale, La Louviere (Belgium); Silva, Mario; Bankier, Alexander A. [Harvard Medical School, Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA (United States)

    2015-06-01

    To compare CT lung volumetry (CTLV) measurements provided by different software packages, and to provide normative data for lung densitometric measurements in healthy individuals. This retrospective study included 51 chest CTs of 17 volunteers (eight men and nine women; mean age, 30 ± 6 years), who underwent spirometrically monitored CT at total lung capacity (TLC), functional residual capacity (FRC), and mean inspiratory capacity (MIC). Volumetric differences assessed by four commercial software packages were compared with analysis of variance (ANOVA) for repeated measurements and benchmarked against the threshold for acceptable variability between spirometric measurements. Mean lung density (MLD) and parenchymal heterogeneity (MLD-SD) were also compared with ANOVA. Volumetric differences ranged from 12 to 213 ml (0.20 % to 6.45 %). Although 16/18 comparisons (among four software packages at TLC, MIC, and FRC) were statistically significant (P < 0.001 to P = 0.004), only 3/18 comparisons, one at MIC and two at FRC, exceeded the spirometry variability threshold. MLD and MLD-SD significantly increased with decreasing volumes, and were significantly larger in lower compared to upper lobes (P < 0.001). Lung volumetric differences provided by different software packages are small. These differences should not be interpreted based on statistical significance alone, but together with absolute volumetric differences. (orig.)

  8. Comparison of cone-beam CT-guided and CT fluoroscopy-guided transthoracic needle biopsy of lung nodules

    Energy Technology Data Exchange (ETDEWEB)

    Rotolo, Nicola; Imperatori, Andrea; Arlant, Veronica; Dominioni, Lorenzo [Insubria University, Center for Thoracic Surgery, Varese (Italy); Floridi, Chiara; Fontana, Federico; Ierardi, Anna Maria; Mangini, Monica; De Marchi, Giuseppe; Fugazzola, Carlo; Carrafiello, Gianpaolo [Insubria University, Radiology Department, Varese (Italy); Novario, Raffaele [Insubria University, Medical Physics Department, Varese (Italy)

    2016-02-15

    To compare the diagnostic performance of cone-beam CT (CBCT)-guided and CT fluoroscopy (fluoro-CT)-guided technique for transthoracic needle biopsy (TNB) of lung nodules. The hospital records of 319 consecutive patients undergoing 324 TNBs of lung nodules in a single radiology unit in 2009-2013 were retrospectively evaluated. The newly introduced CBCT technology was used to biopsy 123 nodules; 201 nodules were biopsied by conventional fluoro-CT-guided technique. We assessed the performance of the two biopsy systems for diagnosis of malignancy and the radiation exposure. Nodules biopsied by CBCT-guided and by fluoro-CT-guided technique had similar characteristics: size, 20 ± 6.5 mm (mean ± standard deviation) vs. 20 ± 6.8 mm (p = 0.845); depth from pleura, 15 ± 15 mm vs. 15 ± 16 mm (p = 0.595); malignant, 60 % vs. 66 % (p = 0.378). After a learning period, the newly introduced CBCT-guided biopsy system and the conventional fluoro-CT-guided system showed similar sensitivity (95 % and 92 %), specificity (100 % and 100 %), accuracy for diagnosis of malignancy (96 % and 94 %), and delivered non-significantly different median effective doses [11.1 mSv (95 % CI 8.9-16.0) vs. 14.5 mSv (95 % CI 9.5-18.1); p = 0.330]. The CBCT-guided and fluoro-CT-guided systems for lung nodule biopsy are similar in terms of diagnostic performance and effective dose, and may be alternatively used to optimize the available technological resources. (orig.)

  9. Comparison of Low- and Standard-Dose CT for the Diagnosis of Acute Appendicitis: A Meta-Analysis.

    Science.gov (United States)

    Yun, Seong Jong; Ryu, Chang-Woo; Choi, Na Young; Kim, Hyun Cheol; Oh, Ji Young; Yang, Dal Mo

    2017-06-01

    A meta-analysis was performed to compare low-dose CT and standard-dose CT in the diagnosis of acute appendicitis with an emphasis on diagnostic value. A systematic literature search for articles published through June 2016 was performed to identify studies that compared low-dose CT with standard-dose CT for the evaluation of patients suspected of having acute appendicitis. Summary estimates of sensitivity and specificity with 95% CIs were calculated using a bivariate random-effects model. Meta-regression was used to perform statistical comparisons of low-dose CT and standard-dose CT. Of 154 studies, nine studies investigating a total of 2957 patients were included in this meta-analysis. The pooled sensitivity and specificity of low-dose CT were 96.25% (95% CI, 91.88-98.31%) and 93.22% (95% CI, 88.75-96.00%), respectively. The pooled sensitivity and specificity of standard-dose CT were 96.40% (95% CI, 93.55-98.02%) and 92.17% (95% CI, 88.24-94.86%), respectively. In a joint model estimation of meta-regression, lowand standard-dose CT did not show a statistically significant difference (p = 0.71). Both lowand standard-dose CT seem to be characterized by high positive and negative predictive values across a broad spectrum of pretest probabilities for acute appendicitis. Low-dose CT is highly effective for the diagnosis of suspected appendicitis and can be considered a valid alternative first-line imaging test that reduces the potential risk of exposure to ionizing radiation.

  10. Model-based iterative reconstruction in ultra-low-dose pediatric chest CT: comparison with adaptive statistical iterative reconstruction.

    Science.gov (United States)

    Kim, Hae Jin; Yoo, So-Young; Jeon, Tae Yeon; Kim, Ji Hye

    2016-01-01

    To evaluate image quality and dose reduction of ultra-low-dose pediatric chest CT reconstructed with model-based iterative reconstruction (MBIR), as compared with adaptive statistical iterative reconstruction (ASIR). Fifty-seven patients (mean age 14 years, M:F=31:26) who underwent ultra-low-dose chest CT reconstructed with both MBIR and ASIR were enrolled in the study. The subjective and objective image qualities of both reconstruction techniques were assessed by 3 radiologists, and compared using statistical analysis. We also evaluated radiation dose of ultra-low-dose chest CT as well as degree of dose reduction in comparison to the prior CT (either standard dose or reduced dose protocol) available in 36 patients. The image quality of MBIR was superior to ASIR both subjectively and objectively. While MBIR showed preserved diagnostic acceptability in 100%, ASIR showed 92% at mean 0.31 mSv (range, 0.13-0.57 mSv) ultra-low-dose CT. In the 36 patients who underwent the prior CT, mean decrease in size-specific dose estimate (SSDE) and dose length product (DLP) at ultra-low-dose CT was 88% (range, 34% - 98%) and 86% (range,42% - 99%), respectively. MBIR significantly improves image quality, as compared to ASIR. Furthermore, MBIR facilitates diagnostically acceptable ultra-low-dose chest CT with nearly 90% less radiation. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Comparison of virtual unenhanced CT images of the abdomen under different iodine flow rates.

    Science.gov (United States)

    Li, Yongrui; Li, Ye; Jackson, Alan; Li, Xiaodong; Huang, Ning; Guo, Chunjie; Zhang, Huimao

    2017-01-01

    To assess the effect of varying iodine flow rate (IFR) and iodine concentration on the quality of virtual unenhanced (VUE) images of the abdomen obtained with dual-energy CT. 94 subjects underwent unenhanced and triphasic contrast-enhanced CT scan of the abdomen, including arterial phase, portal venous phase, and delayed phase using dual-energy CT. Patients were randomized into 4 groups with different IFRs or iodine concentrations. VUE images were generated at 70 keV. The CT values, image noise, SNR and CNR of aorta, portal vein, liver, liver lesion, pancreatic parenchyma, spleen, erector spinae, and retroperitoneal fat were recorded. Dose-length product and effective dose for an examination with and without plain phase scan were calculated to assess the potential dose savings. Two radiologists independently assessed subjective image quality using a five-point scale. The Kolmogorov-Smirnov test was used first to test for normal distribution. Where data conformed to a normal distribution, analysis of variance was used to compare mean HU values, image noise, SNRs and CNRs for the 4 image sets. Where data distribution was not normal, a nonparametric test (Kruskal-Wallis test followed by stepwise step-down comparisons) was used. The significance level for all tests was 0.01 (two-sided) to allow for type 2 errors due to multiple testing. The CT numbers (HU) of VUE images showed no significant differences between the 4 groups (p > 0.05) or between different phases within the same group (p > 0.05). VUE images had equal or higher SNR and CNR than true unenhanced images. VUE images received equal or lower subjective image quality scores than unenhanced images but were of acceptable quality for diagnostic use. Calculated dose-length product and estimated dose showed that the use of VUE images in place of unenhanced images would be associated with a dose saving of 25%. VUE images can replace conventional unenhanced images. VUE images are not affected by varying iodine

  12. Virtual autopsy: two- and three-dimensional multidetector CT findings in drowning with autopsy comparison.

    Science.gov (United States)

    Levy, Angela D; Harcke, H Theodore; Getz, John M; Mallak, Craig T; Caruso, James L; Pearse, Lisa; Frazier, Aletta A; Galvin, Jeffrey R

    2007-06-01

    To retrospectively determine the multidetector computed tomographic (CT) virtual autopsy findings of death by drowning in comparison with autopsy findings. The institutional review board of the Armed Forces Institute of Pathology approved this HIPAA-compliant study and did not require informed consent by the next of kin. Total-body multidetector CT was performed, immediately prior to routine autopsy, in 28 consecutive male subjects (mean age, 24.2 years) who died of drowning and a control group of 12 consecutive male subjects (mean age, 50.8 years) who died of sudden death from atherosclerotic coronary artery disease. Images were evaluated for the presence of fluid and sediment in the paranasal sinuses and airways, mastoid air cell fluid, frothy fluid in the airways, pulmonary opacity (ground-glass opacity or airspace consolidation), interlobular septal thickening, and gastric distention and contents (fluid or sediment). Image findings were compared with findings from autopsy reports and photographs. All drowning subjects had fluid in the paranasal sinuses and mastoid air cells and had ground-glass opacity within the lungs. Twenty-six subjects (93%) had fluid in the subglottic trachea and main bronchi. Fourteen subjects (50%) had high-attenuation sediment in the subglottic airways. Frothy fluid in the airways was present in six subjects (21%). Twenty-five (89%) of the drowning subjects had pulmonary ground-glass opacity with septal lines, which was mild with apical and perihilar distribution in 12 subjects, severe and diffuse in nine, posterior and basilar in three, and limited to the apices in one (not assessed in three of 28 subjects because of decomposition). Control subjects showed mastoid cell fluid (25%), sinus fluid (83%), subglottic airway fluid (92%), and pulmonary ground-glass opacity (100%) but did not have evidence of frothy airway fluid or high-attenuation sediment in the airways. The multidetector CT finding of frothy airway fluid or high

  13. Detection of the anatomic structure and pathology in animal lung specimens: comparison of micro CT and multi-detector row CT

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Kun Young [National Cancer Center, Goyang (Korea, Republic of); Lee, Hyun Ju; Lee, Chang Hyun; Son, Kyu Ri; Goo, Jin Mo; Im, Jung Gi [Seoul National University Hospital and the Institute of Radiation Medicine, Seoul (Korea, Republic of); Seo, Joon Beom [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2006-05-15

    We wanted to compare the capability of micro CT and the clinically available thin-slice multi-detector row CT (MDCT) for demonstrating fine anatomic structures and pathological lesions in formalin-fixed lung specimens. The porcine lung with shark liver oil-induced lipoid pneumonia and the canine lung with pulmonary paragonimiasis were fixed by ventilating them with formalin vapor, and they were then sliced into one-centimeter thick sections. Micro CT (section thickness, 18 micrometer) and MDCT (section thickness, 0.75 mm) images were acquired in four of the lung slices of the lipoid pneumonia specimen and in five of the lung slices of the paragonimiasis specimen. On 62 pairs of micro CT and MDCT images, 169 pairs of rectangular ROIs were manually drawn in the corresponding locations. Two chest radiologists recorded the detectability of three kinds of anatomic structures (lobular core structure, interlobular septum and small bronchiolar lumen) and two kinds of pathological lesions (ground-glass opacity and consolidation) with using a five-point scale. The statistical comparison was performed by using the Wilcoxon signed rank test. Interobserver agreement was evaluated with kappa statistics. For all observers, all the kinds of anatomic structures and pathological lesions were detected better on the micro CT images than on the MDCT images ({rho} < 0.01). Agreement was fair between two observers ({kappa} = 0.38, {rho} < 0.001). The fine anatomic structures and pathological lesions of the lung were more accurately demonstrated on micro CT than on thin-slice MDCT in the inflated and fixed lung specimens.

  14. Multidetector-Row CT Angiography of Cerebral Vasospasm after Aneurysmal Subarachnoid Hemorrhage: Comparison of Bone Subtraction and Standard CT Angiography with Digital Subtraction Angiography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Hee; You, Jin Jong; Choi, Ho Cheol; Kim, Ji Eun [Dept. of Radiology, Gyeongsang National University Hospital, Jinju (Korea, Republic of); Choi, Dae Seob [Gyeongsang Institue of Health Science, Gyeongsang National University School of Medicine, Jinju (Korea, Republic of); Ryoo, Jae Wook [Dept. of Radiology, Samsung Seoul Hospital, Seoul (Korea, Republic of)

    2011-10-15

    To evaluate the usefulness of multidetector-row CT angiography (MDCTA) for the diagnosis of cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) by comparison of digital subtraction angiography (DSA) and to compare the bone subtraction CT angiography (BS-CTA) and standard CT angiography (S-CTA). Thirty-three patients who were treated with intraarterial nimodipine infusion for the cerebral vasospasm after aneurysmal SAH were evaluated with MDCTA and DSA. BS-CTA images were reconstructed from the S-CTA and unenhanced CT source images. A total of 207 vascular segments were evaluated. A four-step scale for the degree of stenosis was applied for each segment. With DSA as the standard images, BS-CTA and S-CTA images were comparied. On DSA, 56 segments (27%) presented vasospasm. Concordance between the DSA and S-CTA and between DSA and BS-CTA were 94.7% and 82.1%, respectively. Overestimation for the degree of stenosis was shown in 37 segments on BS-CTA and in 8 segments on S-CTA, but underestimated segments were only shown on S-CTA (n = 4). MDCTA with standard technique seems to be a useful imaging tool for the evaluation of the cerebral vasospasm after aneurysmal SAH. However, BS-CTA is not needed because of additional radiation and overestimation of the degree of stenosis.

  15. Comparison of an adaptive local thresholding method on CBCT and µCT endodontic images

    Science.gov (United States)

    Michetti, Jérôme; Basarab, Adrian; Diemer, Franck; Kouame, Denis

    2018-01-01

    Root canal segmentation on cone beam computed tomography (CBCT) images is difficult because of the noise level, resolution limitations, beam hardening and dental morphological variations. An image processing framework, based on an adaptive local threshold method, was evaluated on CBCT images acquired on extracted teeth. A comparison with high quality segmented endodontic images on micro computed tomography (µCT) images acquired from the same teeth was carried out using a dedicated registration process. Each segmented tooth was evaluated according to volume and root canal sections through the area and the Feret’s diameter. The proposed method is shown to overcome the limitations of CBCT and to provide an automated and adaptive complete endodontic segmentation. Despite a slight underestimation (‑4, 08%), the local threshold segmentation method based on edge-detection was shown to be fast and accurate. Strong correlations between CBCT and µCT segmentations were found both for the root canal area and diameter (respectively 0.98 and 0.88). Our findings suggest that combining CBCT imaging with this image processing framework may benefit experimental endodontology, teaching and could represent a first development step towards the clinical use of endodontic CBCT segmentation during pulp cavity treatment.

  16. Comparison of near-infrared spectroscopy with CT cerebral blood flow measurements in newborn piglets

    Science.gov (United States)

    Brown, Derek W.; Picot, Paul A.; Springett, Roger; Delpy, David T.; Lee, Ting-Yim

    2001-05-01

    Severely premature infants are often at high risk of cerebral hemorrhage or ischemic injury due to their inability to properly regulate blood flow to the brain. If blood flow is too high, the infant is at risk of cerebral hemorrhage, while too little blood flow can result in ischemic injury. The purpose of this research is to design and develop a means of non-invasively measuring cerebral blood flow (CBF) with near infrared spectroscopy (NIRS). Such a device would greatly aid the diagnosis and monitoring of afflicted infants. Previous attempts to measure CBF with NIRS have achieved limited success. In this study we acquired high signal-to-noise NIR spectrum from 600 to 980 nm with a cooled CCD spectrometer. This spectrometer enables the differential path length factor (DPF) to be estimated with accuracy using a second derivative technique described by Matcher et al. The validity of our new approach is determined via direct comparison with a previously validated computed tomography (CT) method. Three newborn piglets were studied. CBF measurements were performed at various partial arterial CO2 tensions (PaCO2) using both the NIRS and CT methods. The results of the two methods correlate well with a relationship of CBFCT equals -4.30 + 1.05 CBFNIRS (r2 equals 0.96).

  17. A comparison between intrastomal 3D ultrasonography, CT scanning and findings at surgery in patients with stomal complaints.

    Science.gov (United States)

    Näsvall, P; Wikner, F; Gunnarsson, U; Rutegård, J; Strigård, K

    2014-10-01

    Since there are no reliable investigative tools for imaging parastomal hernia, new techniques are needed. The aim of this study was to assess the validity of intrastomal three-dimensional ultrasonography (3D) as an alternative to CT scanning for the assessment of stomal complaints. Twenty patients with stomal complaints, indicating surgery, were examined preoperatively with a CT scan in the supine position and 3D intrastomal ultrasonography in the supine and erect positions. Comparison with findings at surgery, considered to be the true state, was made. Both imaging methods, 3D ultrasonography and CT scanning, showed high sensitivity (ultrasound 15/18, CT scan 15/18) and specificity (ultrasound 2/2, CT scan 1/2) when judged by a dedicated radiologist. Corresponding values for interpretation of CT scans in routine clinical practice was for sensitivity 17/18 and for specificity 1/2. 3D ultrasonography has a high validity and is a promising alternative to CT scanning in the supine position to distinguish a bulge from a parastomal hernia.

  18. Advances in CT imaging for urolithiasis

    Directory of Open Access Journals (Sweden)

    Yasir Andrabi

    2015-01-01

    Full Text Available Urolithiasis is a common disease with increasing prevalence worldwide and a lifetime-estimated recurrence risk of over 50%. Imaging plays a critical role in the initial diagnosis, follow-up and urological management of urinary tract stone disease. Unenhanced helical computed tomography (CT is highly sensitive (>95% and specific (>96% in the diagnosis of urolithiasis and is the imaging investigation of choice for the initial assessment of patients with suspected urolithiasis. The emergence of multi-detector CT (MDCT and technological innovations in CT such as dual-energy CT (DECT has widened the scope of MDCT in the stone disease management from initial diagnosis to encompass treatment planning and monitoring of treatment success. DECT has been shown to enhance pre-treatment characterization of stone composition in comparison with conventional MDCT and is being increasingly used. Although CT-related radiation dose exposure remains a valid concern, the use of low-dose MDCT protocols and integration of newer iterative reconstruction algorithms into routine CT practice has resulted in a substantial decrease in ionizing radiation exposure. In this review article, our intent is to discuss the role of MDCT in the diagnosis and post-treatment evaluation of urolithiasis and review the impact of emerging CT technologies such as dual energy in clinical practice.

  19. A comparison study: image-based vs signal-based retrospective gating on microCT

    Science.gov (United States)

    Liu, Xuan; Salmon, Phil L.; Laperre, Kjell; Sasov, Alexander

    2017-09-01

    Retrospective gating on animal studies with microCT has gained popularity in recent years. Previously, we use ECG signals for cardiac gating and breathing airflow or video signals of abdominal motion for respiratory gating. This method is adequate and works well for most applications. However, through the years, researchers have noticed some pitfalls in the method. For example, the additional signal acquisition step may increase failure rate in practice. X-Ray image-based gating, on the other hand, does not require any extra step in the scanning. Therefore we investigate imagebased gating techniques. This paper presents a comparison study of the image-based versus signal-based approach to retrospective gating. The two application areas we have studied are respiratory and cardiac imaging for both rats and mice. Image-based respiratory gating on microCT is relatively straightforward and has been done by several other researchers and groups. This method retrieves an intensity curve of a region of interest (ROI) placed in the lung area on all projections. From scans on our systems based on step-and-shoot scanning mode, we confirm that this method is very effective. A detailed comparison between image-based and signal-based gating methods is given. For cardiac gating, breathing motion is not negligible and has to be dealt with. Another difficulty in cardiac gating is the relatively smaller amplitude of cardiac movements comparing to the respirational movements, and the higher heart rate. Higher heart rate requires high speed image acquisition. We have been working on our systems to improve the acquisition speed. A dual gating technique has been developed to achieve adequate cardiac imaging.

  20. Xenon-enhanced CT using subtraction CT: Basic and preliminary clinical studies for comparison of its efficacy with that of dual-energy CT and ventilation SPECT/CT to assess regional ventilation and pulmonary functional loss in smokers.

    Science.gov (United States)

    Ohno, Yoshiharu; Yoshikawa, Takeshi; Takenaka, Daisuke; Fujisawa, Yasuko; Sugihara, Naoki; Kishida, Yuji; Seki, Shinichiro; Koyama, Hisanobu; Sugimura, Kazuro

    2017-01-01

    To prospectively and directly compare the capability for assessments of regional ventilation and pulmonary functional loss in smokers of xenon-ventilation CT obtained with the dual-energy CT (DE-CT) and subtraction CT (Sub-CT) MATERIALS AND METHODS: Twenty-three consecutive smokers (15 men and 8 women, mean age: 69.7±8.7years) underwent prospective unenhanced and xenon-enhanced CTs, the latter by Sub-CT and DE-CT methods, ventilation SPECT and pulmonary function tests. Sub-CT was generated from unenhanced and xenon-enhanced CT, and all co-registered SPECT/CT data were produced from SPECT and unenhanced CT data. For each method, regional ventilation was assessed by using a 11-point scoring system on a per-lobe basis. To determine the functional lung volume by each method, it was also calculated for individual sublets with a previously reported method. To determine inter-observer agreement for each method, ventilation defect assessment was evaluated by using the χ2 test with weighted kappa statistics. For evaluation of the efficacy of each method for pulmonary functional loss assessment, functional lung volume was correlated with%FEV1. Each inter-observer agreement was rated as substantial (Sub-CT: κ=0.69, pXenon-enhanced CT obtained by Sub-CT can be considered at least as efficacious as that obtained by DE-CT and SPECT/CT for assessment of ventilation abnormality and pulmonary functional loss in smokers. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  1. Comparison between ultrasound and noncontrast helical computed tomography for identification of acute ureterolithiasis in a teaching hospital setting

    Directory of Open Access Journals (Sweden)

    Luís Ronan Marquez Ferreira de Souza

    2007-03-01

    Full Text Available CONTEXT AND OBJECTIVE: Recent studies have shown noncontrast computed tomography (NCT to be more effective than ultrasound (US for imaging acute ureterolithiasis. However, to our knowledge, there are few studies directly comparing these techniques in an emergency teaching hospital setting. The objectives of this study were to compare the diagnostic accuracy of US and NCT performed by senior radiology residents for diagnosing acute ureterolithiasis; and to assess interobserver agreement on tomography interpretations by residents and experienced abdominal radiologists. DESIGN AND SETTING: Prospective study of 52 consecutive patients, who underwent both US and NCT within an interval of eight hours, at Hospital São Paulo. METHODS: US scans were performed by senior residents and read by experienced radiologists. NCT scan images were read by senior residents, and subsequently by three abdominal radiologists. The interobserver variability was assessed using the kappa statistic. RESULTS: Ureteral calculi were found in 40 out of 52 patients (77%. US presented sensitivity of 22% and specificity of 100%. When collecting system dilatation was associated, US demonstrated 73% sensitivity, 82% specificity. The interobserver agreement in NCT analysis was very high with regard to identification of calculi, collecting system dilatation and stranding of perinephric fat. CONCLUSIONS: US has limited value for identifying ureteral calculi in comparison with NCT, even when collecting system dilatation is present. Residents and abdominal radiologists demonstrated excellent agreement rates for ureteral calculi, identification of collecting system dilatation and stranding of perinephric fat on NCT.

  2. Comparison of image registration based measures of regional lung ventilation from dynamic spiral CT with Xe-CT.

    Science.gov (United States)

    Ding, Kai; Cao, Kunlin; Fuld, Matthew K; Du, Kaifang; Christensen, Gary E; Hoffman, Eric A; Reinhardt, Joseph M

    2012-08-01

    Regional lung volume change as a function of lung inflation serves as an index of parenchymal and airway status as well as an index of regional ventilation and can be used to detect pathologic changes over time. In this paper, the authors propose a new regional measure of lung mechanics-the specific air volume change by corrected Jacobian. The authors compare this new measure, along with two existing registration based measures of lung ventilation, to a regional ventilation measurement derived from xenon-CT (Xe-CT) imaging. 4DCT and Xe-CT datasets from four adult sheep are used in this study. Nonlinear, 3D image registration is applied to register an image acquired near end inspiration to an image acquired near end expiration. Approximately 200 annotated anatomical points are used as landmarks to evaluate registration accuracy. Three different registration based measures of regional lung mechanics are derived and compared: the specific air volume change calculated from the Jacobian (SAJ); the specific air volume change calculated by the corrected Jacobian (SACJ); and the specific air volume change by intensity change (SAI). The authors show that the commonly used SAI measure can be derived from the direct SAJ measure by using the air-tissue mixture model and assuming there is no tissue volume change between the end inspiration and end expiration datasets. All three ventilation measures are evaluated by comparing to Xe-CT estimates of regional ventilation. After registration, the mean registration error is on the order of 1 mm. For cubical regions of interest (ROIs) in cubes with size 20 mm × 20 mm × 20 mm, the SAJ and SACJ measures show significantly higher correlation (linear regression, average r(2) = 0.75 and r(2) = 0.82) with the Xe-CT based measure of specific ventilation (sV) than the SAI measure. For ROIs in slabs along the ventral-dorsal vertical direction with size of 150 mm × 8 mm × 40 mm, the SAJ, SACJ, and SAI all show high correlation (linear

  3. Comparison of two different segmentation methods on planar lung perfusion scan with reference to quantitative value on SPECT/CT

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Min Seok; Kang, Yeon Koo; Ha, Seung Gyun [Dept. of Nuclear Medicine, Seoul National University Hospital, Seoul (Korea, Republic of); and others

    2017-06-15

    Until now, there was no single standardized regional segmentation method of planar lung perfusion scan. We compared planar scan based two segmentation methods, which are frequently used in the Society of Nuclear Medicine, with reference to the lung perfusion single photon emission computed tomography (SPECT)/computed tomography (CT) derived values in lung cancer patients. Fifty-five lung cancer patients (male:female, 37:18; age, 67.8 ± 10.7 years) were evaluated. The patients underwent planar scan and SPECT/CT after injection of technetium-99 m macroaggregated albumin (Tc-99 m-MAA). The % uptake and predicted postoperative percentage forced expiratory volume in 1 s (ppoFEV1%) derived from both posterior oblique (PO) and anterior posterior (AP) methods were compared with SPECT/CT derived parameters. Concordance analysis, paired comparison, reproducibility analysis and spearman correlation analysis were conducted. The % uptake derived from PO method showed higher concordance with SPECT/CT derived % uptake in every lobe compared to AP method. Both methods showed significantly different lobar distribution of % uptake compared to SPECT/CT. For the target region, ppoFEV1% measured from PO method showed higher concordance with SPECT/CT, but lower reproducibility compared to AP method. Preliminary data revealed that every method significantly correlated with actual postoperative FEV1%, with SPECT/CT showing the best correlation. The PO method derived values showed better concordance with SPECT/CT compared to the AP method. Both PO and AP methods showed significantly different lobar distribution compared to SPECT/CT. In clinical practice such difference according to different methods and lobes should be considered for more accurate postoperative lung function prediction.

  4. Spin versus helicity in processes involving transversity

    CERN Document Server

    Mekhfi, Mustapha

    2011-01-01

    We construct the spin formalism in order to deal in a direct and natural way with processes involving transversity which are now of increasing popularity. The helicity formalism which is more appropriate for collision processes of definite helicity has been so far used also to manage processes with transversity, but at the price of computing numerous helicity amplitudes generally involving unnecessary kinematical variables.In a second step we work out the correspondence between both formalisms and retrieve in another way all results of the helicity formalism but in simpler forms.We then compute certain processes for comparison.A special process:the quark dipole magnetic moment is shown to be exclusively treated within the spin formalism as it is directly related to the transverse spin of the quark inside the baryon.

  5. Helicity of the Neutrino

    Indian Academy of Sciences (India)

    IAS Admin

    Helicity for a particle is defined as the projection of the particle's spin along its direction of motion. For a massive particle, the sign of its helicity depends on the frame of reference ... A team of three scientists at Brookhaven National Lab- oratory, M Goldhaber, L Grodzins and A W Sunyar set about to rectify the situation.

  6. A Clinical and Experimental Comparison of Time of Flight PET/MRI and PET/CT Systems.

    Science.gov (United States)

    Oprea-Lager, Daniela E; Yaqub, Maqsood; Pieters, Indra C; Reinhard, Rinze; van Moorselaar, Reindert J A; van den Eertwegh, Alfons J M; Hoekstra, Otto S; Lammertsma, Adriaan A; Boellaard, Ronald

    2015-10-01

    The purpose of the study was to compare image quality and quantitative accuracy of positron emission tomography/magnetic resonance imaging (PET/MRI) and PET/computed tomography (PET/CT) systems with time of flight PET gantries, using phantom and clinical studies. Identical phantom experiments were performed on both systems. Calibration, uniformity, and standardized uptake value (SUV) recovery were measured. A clinical PET/CT versus PET/MRI comparison was performed using [(18)F]fluoromethylcholine ([(18)F]FCH). Calibration accuracy and image uniformity were comparable between systems. SUV recovery met EANM/EARL requirements on both scanners. Thirty-four lesions with comparable PET image quality were identified. Lesional SUVmax differences of 4 ± 26% between PET/MRI and PET/CT data were observed (R (2) = 0.79, slope = 1.02). In healthy tissues, PET/MRI-derived SUVs were 16 ± 11% lower than on PET/CT (R (2) = 0.98, slope = 0.86). PET/MRI and PET/CT showed comparable performance with respect to calibration accuracy, image uniformity, and SUV recovery. [(18)F]FCH uptake values for both healthy tissues and lesions corresponded reasonably well between MR- and CT-based systems, but only in regions free of MR-based attenuation artifacts.

  7. [Preoperative accuracy of selective laser sintering (SLS) in craniofacial 3D modeling: comparison with patient CT data].

    Science.gov (United States)

    Kaim, A H; Kirsch, E C; Alder, P; Bucher, P; Hammer, B

    2009-07-01

    To evaluate the accuracy of craniofacial 3D models produced in the standardized selective laser sintering (SLS) technique from multislice computed tomography (MSCT) data sets in comparison with patient data and to investigate the effect of potential causes of inaccuracies. 19 models were considered and examined by MSCT. The patient CT data used for 3D modeling was analyzed and compared to the 3D model data. 15 anatomical landmarks were defined and 20 distances were digitally measured. The digital measurements of both CT data sets were compared to manually measured distances of the SLS model. There was not a statistically significant difference (p < 0.05) between the measurements of the distances concerning all three groups (patient CT data, model CT data, manual measurement of the model). The mean values of the differences were between 0.5455 and -0.3214 mm. We found a high accuracy of SLS 3D models, which is due to a high precision in the modeling process and to the small voxel size of patient CT data achieved by MSCT. Anatomical landmarks in patient and model CT data sets and on the 3D model were able to be accurately reproduced, which is important for preoperative planning.

  8. Diagnosis of coronary artery disease. Current status of CT; Diagnostik der koronaren Herzkrankheit. Aktueller Stand der CT

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Martin H.K.; Klass, O.; Brunner, H. [Klinik fuer Diagnostische und Interventionelle Radiologie, Unikliniken Ulm (Germany)

    2010-06-15

    Continuous technical innovations during the last years have established cardiac CT as a modality for noninvasive coronary angiography in clinical routine. 64 detector row generations and beyond have shown high diagnostic accuracy for obstructive stenosis detection in comparison to the standard of reference catheterization angiography. But the high radiation dose exposure associated with helical cardiac CT acquisition has sparked increasing concern in the medical community. The issue has been addressed with the newest releases of technology. Dose reduction by 80% and more is achieved with modified scan techniques rendering the method suitable for clinical routine. Symptomatic patients with an intermediate pre-test probability have been identified as the most suitable candidates for CT coronary angiography. Other appropriate indications include the rapid assessment of bypass grafts and suspected coronary anomalies. CT coronary angiography has been shown to be cost effective for the evaluation of patients with acute chest pain in the emergency department. But CT is able to provide more than coronary morphology, initial feasibility testing has shown that CT first-pass myocardial imaging can visualize perfusion defects with adenosine induced vasodilatation. Coronary morphology and functional perfusion studies have been shown to be complementary providing incremental diagnostic value over either technique alone. In the next few years a lot of comparison trials will establish the best suitable perfusion method (SPECT, MRI or CT) for hybrid imaging with CT coronary angiography. (orig.)

  9. Quantification of Pathologic Air Trapping in Lung Transplant Patients Using CT Density Mapping: Comparison with Other CT Air Trapping Measures.

    Directory of Open Access Journals (Sweden)

    Olga Solyanik

    Full Text Available To determine whether density mapping (DM is more accurate for detection and quantification of pathologic air trapping (pAT in patients after lung transplantation compared to other CT air trapping measures. One-hundred forty-seven lung and heart-lung transplant recipients underwent CT-examinations at functional residual capacity (FRC and total lung capacity (TLC and PFT six months after lung transplantation. Quantification of air trapping was performed with the threshold-based method in expiration (EXP, density mapping (DM and the expiratory to inspiratory ratio of the mean lung density (E/I-ratio MLD. A non-rigid registration of inspiration-expiration CT-data with a following voxel-to-voxel mapping was carried out for DM. Systematic variation of attenuation ranges was performed for EXP and DM and correlated with the ratio of residual volume to total lung capacity (RV/TLC by Spearman rank correlation test. AT was considered pathologic if RV/TLC was above the 95th percentile of the predicted upper limit of normal values. Receiver operating characteristic (ROC analysis was performed. The optimal attenuation range for the EXP method was from -790 HU to -950 HU (EXP(-790 to -950HU (r = 0.524, p<0.001 to detect air trapping. Within the segmented lung parenchyma, AT was best defined as voxel difference less than 80 HU between expiration and registered inspiration using the DM method. DM correlated best with RV/TLC (r = 0.663, p<0.001. DM and E/I-ratio MLD showed a larger AUC (0.78; 95% CI 0.69-0.86; 0.76, 95% CI 0.67-0.85 than EXP(-790 HU to -950 HU (0.71, 95% CI 0.63-0.78. DM and E/I-ratio MLD showed better correlation with RV/TLC and are more suited quantitative CT-methods to detect pAT in lung transplant patients than the EXP(-790HU to -950HU.

  10. Comparison of image quality and radiation dose of coronary computed tomographic angiography between conventional helical scanning and a strategy incorporating sequential scanning.

    Science.gov (United States)

    Einstein, Andrew J; Wolff, Steven D; Manheimer, Eric D; Thompson, James; Terry, Sylvia; Uretsky, Seth; Pilip, Adalbert; Peters, M Robert

    2009-11-15

    Radiation dose from coronary computed tomographic angiography may be decreased using a sequential scanning protocol rather than a conventional helical scanning protocol. We compared radiation dose and image quality from coronary computed tomographic angiography in a single center between an initial period during which helical scanning with electrocardiographically controlled tube current modulation was used for all patients (n = 138) and after adoption of a strategy incorporating sequential scanning whenever appropriate (n = 261). Using the sequential-if-appropriate strategy, sequential scanning was employed in 86.2% of patients. Compared to the helical-only strategy, this strategy was associated with a 65.1% dose decrease (mean dose-length product [DLP] 305.2 vs 875.1 and mean effective dose 14.9 vs 5.2 mSv, respectively), with no significant change in overall image quality, step artifacts, motion artifacts, or perceived image noise. For the 225 patients undergoing sequential scanning, the DLP was 201.9 +/- 90.0 mGy x cm; for patients undergoing helical scanning under either strategy, the DLP was 890.9 +/- 293.3 mGy x cm (p strategy. In conclusion, a sequential-if-appropriate diagnostic strategy decreases dose markedly compared to a helical-only strategy, with no significant difference in image quality.

  11. Comparison of effective dose for imaging of mandible between multi-detector CT and cone-beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Dae Kyo; Lee, Sang Chul; Huh, Kyung Hoe; Yi, Won Jin; Lee, Sam Sun; Choi, Soon Chul [School of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    2012-06-15

    The aim of this study was to compare the effective dose for imaging of mandible between multi-detector computed tomography (MDCT) and cone-beam computed tomography (CBCT). An MDCT with low dose technique was also compared with them. Thermoluminescent dosimeter (TLD) chips were placed at 25 organ sites of an anthropomorphic phantom. The mandible of the phantom was exposed using 2 different types of MDCT units (Somatom Sensation 10 for standard-dose MDCT, Somatom Emotion 6 for low-dose MDCT) and 3 different CBCT units (AZ3000CT, Implagraphy, and Kavo 3D eXaM). The radiation absorbed dose was measured and the effective dose was calculated according to the ICRP 2007 report. The effective dose was the highest for Somatom Sensation 10 (425.84 {mu}Sv), followed by AZ3000CT (332.4 {mu}Sv), Somatom Emotion 6 (199.38 {mu}Sv), and 3D eXaM (111.6 {mu}Sv); it was the lowest for Implagraphy (83.09 {mu}Sv). The CBCT showed significant variation in dose level with different device. The effective doses of MDCTs were not significantly different from those of CBCTs for imaging of mandible. The effective dose of MDCT could be markedly decreased by using the low-dose technique.

  12. Intra-individual diagnostic image quality and organ-specific-radiation dose comparison between spiral cCT with iterative image reconstruction and z-axis automated tube current modulation and sequential cCT.

    Science.gov (United States)

    Wenz, Holger; Maros, Máté E; Meyer, Mathias; Gawlitza, Joshua; Förster, Alex; Haubenreisser, Holger; Kurth, Stefan; Schoenberg, Stefan O; Groden, Christoph; Henzler, Thomas

    2016-01-01

    To prospectively evaluate image quality and organ-specific-radiation dose of spiral cranial CT (cCT) combined with automated tube current modulation (ATCM) and iterative image reconstruction (IR) in comparison to sequential tilted cCT reconstructed with filtered back projection (FBP) without ATCM. 31 patients with a previous performed tilted non-contrast enhanced sequential cCT aquisition on a 4-slice CT system with only FBP reconstruction and no ATCM were prospectively enrolled in this study for a clinical indicated cCT scan. All spiral cCT examinations were performed on a 3rd generation dual-source CT system using ATCM in z-axis direction. Images were reconstructed using both, FBP and IR (level 1-5). A Monte-Carlo-simulation-based analysis was used to compare organ-specific-radiation dose. Subjective image quality for various anatomic structures was evaluated using a 4-point Likert-scale and objective image quality was evaluated by comparing signal-to-noise ratios (SNR). Spiral cCT led to a significantly lower (p < 0.05) organ-specific-radiation dose in all targets including eye lense. Subjective image quality of spiral cCT datasets with an IR reconstruction level 5 was rated significantly higher compared to the sequential cCT acquisitions (p < 0.0001). Consecutive mean SNR was significantly higher in all spiral datasets (FBP, IR 1-5) when compared to sequential cCT with a mean SNR improvement of 44.77% (p < 0.0001). Spiral cCT combined with ATCM and IR allows for significant-radiation dose reduction including a reduce eye lens organ-dose when compared to a tilted sequential cCT while improving subjective and objective image quality.

  13. Comparison of Image Registration Based Measures of Regional Lung Ventilation from Dynamic Spiral CT with Xe-CT

    CERN Document Server

    Ding, Kai; Fuld, Matthew K; Du, Kaifang; Christensen, Gary E; Hoffman, Eric A; Reinhardt, Joseph M

    2012-01-01

    Purpose: Regional lung volume change as a function of lung inflation serves as an index of parenchymal and airway status as well as an index of regional ventilation and can be used to detect pathologic changes over time. In this article, we propose a new regional measure of lung mechanics --- the specific air volume change by corrected Jacobian. Methods: 4DCT and Xe-CT data sets from four adult sheep are used in this study. Nonlinear, 3D image registration is applied to register an image acquired near end inspiration to an image acquired near end expiration. Approximately 200 annotated anatomical points are used as landmarks to evaluate registration accuracy. Three different registration-based measures of regional lung mechanics are derived and compared: the specific air volume change calculated from the Jacobian (SAJ); the specific air volume change calculated by the corrected Jacobian (SACJ); and the specific air volume change by intensity change (SAI). Results: After registration, the mean registration err...

  14. SU-F-J-88: Comparison of Two Deformable Image Registration Algorithms for CT-To-CT Contour Propagation

    Energy Technology Data Exchange (ETDEWEB)

    Gopal, A; Xu, H; Chen, S [University of Maryland School of Medicine, Columbia, MD (United States)

    2016-06-15

    Purpose: To compare the contour propagation accuracy of two deformable image registration (DIR) algorithms in the Raystation treatment planning system – the “Hybrid” algorithm based on image intensities and anatomical information; and the “Biomechanical” algorithm based on linear anatomical elasticity and finite element modeling. Methods: Both DIR algorithms were used for CT-to-CT deformation for 20 lung radiation therapy patients that underwent treatment plan revisions. Deformation accuracy was evaluated using landmark tracking to measure the target registration error (TRE) and inverse consistency error (ICE). The deformed contours were also evaluated against physician drawn contours using Dice similarity coefficients (DSC). Contour propagation was qualitatively assessed using a visual quality score assigned by physicians, and a refinement quality score (0 0.9 for lungs, > 0.85 for heart, > 0.8 for liver) and similar qualitative assessments (VQS < 0.35, RQS > 0.75 for lungs). When anatomical structures were used to control the deformation, the DSC improved more significantly for the biomechanical DIR compared to the hybrid DIR, while the VQS and RQS improved only for the controlling structures. However, while the inclusion of controlling structures improved the TRE for the hybrid DIR, it increased the TRE for the biomechanical DIR. Conclusion: The hybrid DIR was found to perform slightly better than the biomechanical DIR based on lower TRE while the DSC, VQS, and RQS studies yielded comparable results for both. The use of controlling structures showed considerable improvement in the hybrid DIR results and is recommended for clinical use in

  15. Magnetic helical micromachines.

    Science.gov (United States)

    Peyer, Kathrin E; Tottori, Soichiro; Qiu, Famin; Zhang, Li; Nelson, Bradley J

    2013-01-02

    Helical microrobots have the potential to be used in a variety of application areas, such as in medical procedures, cell biology, or lab-on-a-chip. They are powered and steered wirelessly using low-strength rotating magnetic fields. The helical shape of the device allows propulsion through numerous types of materials and fluids, from tissue to different types of bodily fluids. Helical propulsion is suitable for pipe flow conditions or for 3D swimming in open fluidic environments. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Rapid Arc, helical tomotherapy, sliding window intensity modulated radiotherapy and three dimensional conformal radiation for localized prostate cancer: A dosimetric comparison

    Directory of Open Access Journals (Sweden)

    Rajesh A Kinhikar

    2014-01-01

    Full Text Available Objective: The objective of this study was to investigate the potential role of RapidArc (RA compared with helical tomotherapy (HT, sliding window intensity modulated radiotherapy (SW IMRT and three-dimensional conformal radiation therapy (3D CRT for localized prostate cancer. Materials and Methods: Prescription doses ranged from 60 Gy to planning target volume (PTV and 66.25 Gy for clinical target volume prostate (CTV-P over 25-30 fractions. PTV and CTV-P coverage were evaluated by conformity index (CI and homogeneity index (HI. Organ sparing comparison was done with mean doses to rectum and bladder. Results: CI 95 were 1.0 ± 0.01 (RA, 0.99 ± 0.01 (HT, 0.97 ± 0.02 (IMRT, 0.98 ± 0.02 (3D CRT for PTV and 1.0 ± 0.00 (RA, HT, SW IMRT and 3D CRT for CTV-P. HI was 0.11 ± 0.03 (RA, 0.16 ± 0.08 (HT, 0.12 ± 0.03 (IMRT, 0.06 ± 0.01 (3D CRT for PTV and 0.03 ± 0.00 (RA, 0.05 ± 0.01 (HT, 0.03 ± 0.01 (SW IMRT and 3D CRT for CTV-P. Mean dose to bladder were 23.68 ± 13.23 Gy (RA, 24.55 ± 12.51 Gy (HT, 19.82 ± 11.61 Gy (IMRT and 23.56 ± 12.81 Gy (3D CRT, whereas mean dose to rectum was 36.85 ± 12.92 Gy (RA, 33.18 ± 11.12 Gy (HT, IMRT and 38.67 ± 12.84 Gy (3D CRT. Conclusion: All studied intensity-modulated techniques yield treatment plans of significantly improved quality when compared with 3D CRT, with HT providing best organs at risk sparing and RA being the most efficient treatment option, reducing treatment time to 1.45-3.7 min and monitor unit to <400 for a 2 Gy fraction.

  17. Comparison of bone histomorphometry and μCT for evaluating bone quality in tail-suspended rats

    Science.gov (United States)

    Sun, Lian-Wen; Huang, Yun-Fei; Wang, Ying; Luan, Hui-Qin; Fan, Yu-Bo

    2014-10-01

    Astronauts often suffer from microgravity-induced osteoporosis due to their time in space. Bone histomorphometry, the 'gold standard' technique for detecting bone quality, is widely used in the evaluation of osteoporosis. This study investigates whether μCT has the same application value as histomorphometry in the evaluation of weightlessness-induced bone loss. A total of 24 SD rats were distributed into three groups (n = 8, each): tail-suspension (TS), TS plus active exercise (TSA), and control (CON). After 21 days, bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) and μCT, and microstructure was measured by μCT and histomorphometry. BMD was found to have decreased significantly in TS and TSA compared with the CON group. The results of the μCT measurements showed that a change in BMD mainly occurred in the trabecular bone, and the trabecular BMD increased significantly in the TSA compared with the TS group. The comparison of μCT and histomorphometry showed that TS led to a significant decrease in bone volume (BV/TV), trabecular thickness (Tb.Th) and trabecular number (Tb.N), and it led to an increase in trabecular separation (Tb.Sp). However, active exercise can prevent these changes. Significant differences in most parameters between TSA and CON were found by μCT but not by histomorphometry. Additionally, the parameters of these two methods are highly correlated. Therefore, the application value of μCT is as good as histomorphometry and DXA in the diagnosis of weightlessness-induced osteoporosis and is even better in evaluating the efficacy of exercise.

  18. Evaluation of Deep Vein Thrombosis with Multidetector Row CT after Orthopedic Arthroplasty: a Prospective Study for Comparison with Doppler Sonography

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Sung Su; Kim, Youn Jeong; Chun, Yong Sun; Kim, Won Hong [Inha University, College of Medicine, Incheon (Korea, Republic of); Kim, Jeong Ho; Park, Chul Hi [Gachon University, Gil Medical Center, Incheon (Korea, Republic of)

    2008-02-15

    This prospective study evaluated the ability of indirect 16-row multidetector CT venography, in comparison with Doppler sonography, to detect deep vein thrombosis after total hip or knee replacement. Sixty-two patients had undergone orthopedic replacement surgery on a total of 30 hip joints and 54 knee joints. The CT venography (scan delay time: 180 seconds; slice thickness/increment: 2/1.5 mm) and Doppler sonography were performed 8 to 40 days after surgery. We measured the z-axis length of the beam hardening artifact that degraded the image quality so that the presence of deep vein thrombosis couldn't be evaluated on the axial CT images. The incidence and location of deep vein thrombosis was analyzed. The diagnostic performance of the CT venograms was evaluated and compared with that of Doppler sonography as a standard of reference. The z-axis length (mean{+-}standard deviation) of the beam hardening artifact was 4.5{+-}0.8 cm in the arthroplastic knees and 3.9{+-}2.9 cm in the arthroplastic hips. Deep vein thrombosis (DVT) was found in the popliteal or calf veins on Doppler sonography in 30 (48%) of the 62 patients. The CT venography has a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 90%, 97%, 96%, 91% and 94%, respectively. The ability of CT venography to detect DVT was comparable to that of Doppler sonography despite of beam hardening artifact. Therefore, CT venography is feasible to use as an alternative modality for evaluating postarthroplasty patients.

  19. Whole-body adipose tissue analysis: comparison of MRI, CT and dual energy X-ray absorptiometry

    DEFF Research Database (Denmark)

    Kullberg, J; Brandberg, J; Angelhed, J-E

    2009-01-01

    The aim of this study was to validate a recently proposed MRI-based T(1)-mapping method for analysis of whole-body adipose tissue (AT) using an established CT protocol as reference and to include results from dual energy X-ray absorptiometry (DEXA). 10 subjects, drawn from the Swedish Obese Subje......-processing of whole-body MRI data, allowing longitudinal whole-body studies that are also applicable for children and adolescents.......The aim of this study was to validate a recently proposed MRI-based T(1)-mapping method for analysis of whole-body adipose tissue (AT) using an established CT protocol as reference and to include results from dual energy X-ray absorptiometry (DEXA). 10 subjects, drawn from the Swedish Obese...... Subjects Sibling-pairs study, were examined using CT, MRI and DEXA. The CT analysis was based on 28 imaged slices. T(1) maps were calculated using contiguous MRI data from two different gradient echo sequences acquired using different flip angles. CT and MRI comparison was performed slice...

  20. Multi-parametric ultrasound criteria for internal carotid artery disease - comparison with CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Barlinn, Kristian; Kepplinger, Jessica; Siepmann, Timo; Pallesen, Lars-Peder; Bodechtel, Ulf; Reichmann, Heinz; Puetz, Volker [Carl Gustav Carus University Hospital, Technische Universitaet Dresden, Department of Neurology, Dresden (Germany); Floegel, Thomas [Carl Gustav Carus University Hospital, Technische Universitaet Dresden, Department of Neurology, Dresden (Germany); Carl Gustav Carus University Hospital, Technische Universitaet Dresden, Department of Neuroradiology, Dresden (Germany); Kitzler, Hagen H. [Carl Gustav Carus University Hospital, Technische Universitaet Dresden, Department of Neuroradiology, Dresden (Germany); Alexandrov, Andrei V. [The University of Tennessee Health Science Center, Department of Neurology, Memphis, TN (United States)

    2016-09-15

    The German Society of Ultrasound in Medicine (known by its acronym DEGUM) recently proposed a novel multi-parametric ultrasound approach for comprehensive and accurate assessment of extracranial internal carotid artery (ICA) steno-occlusive disease. We determined the agreement between duplex ultrasonography (DUS) interpreted by the DEGUM criteria and CT angiography (CTA) for grading of extracranial ICA steno-occlusive disease. Consecutive patients with acute cerebral ischemia underwent DUS and CTA. Internal carotid artery stenosis was graded according to the DEGUM-recommended criteria for DUS. Independent readers manually performed North American Symptomatic Carotid Endarterectomy Trial-type measurements on axial CTA source images. Both modalities were compared using Spearman's correlation and Bland-Altman analyses. A total of 303 acute cerebral ischemia patients (mean age, 72 ± 12 years; 58 % men; median baseline National Institutes of Health Stroke Scale score, 4 [interquartile range 7]) provided 593 DUS and CTA vessel pairs for comparison. There was a positive correlation between DUS and CTA (r{sub s} = 0.783, p < 0.001) with mean difference in degree of stenosis measurement of 3.57 %. Bland-Altman analysis further revealed widely varying differences (95 % limits of agreement -29.26 to 22.84) between the two modalities. Although the novel DEGUM criteria showed overall good agreement between DUS and CTA across all stenosis ranges, potential for wide incongruence with CTA underscores the need for local laboratory validation to avoid false screening results. (orig.)

  1. Sacroiliitis in Ankylosing Spondylitis: Comparison with Multidetector Row CT and Plain Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Ji Youn; Joo, Kyung Bin; Choi, Byeong Kyoo; Ryu, Jeong Ah; Kim, Tae Hwan; Choi, Woo Jung [Hanyang University Hospital, Seoul (Korea, Republic of)

    2009-03-15

    The objective of our study was to compare multidetector row CT and the plain radiographs for making the diagnosis and grading the sacroiliitis that accompanies ankylosing spondylitis. We wanted to determine the role of multidetector row CT for the evaluation of the sacroilitis in patients with ankylosing spondylitis. One hundred ninety two patients with clinically suspected ankylosing spondylitis were evaluated by conventional radiography and multidetector row CT. Two musculoskeletal radiologists retrospectively analyzed the images, and they graded the sacroiliitis using the modified New York Criteria. Multidetector row CT demonstrated a significantly higher sensitivity (74.5%, 83.3%) than did plain radiography (59.9%, 66.7%) for detecting early sacroiliitis (p<0.05). Multidetector row CT showed a higher grade of sacroiliitis in 114 and 127 of 384 sacroiliac joints. Performing multidetector row CT rather than plain radiography for making the diagnoses of accompanying ankylosing spondylitis allows an early start of treatment with a subsequently improved prognosis

  2. Comparison of immunogenicity test methods used in clinical studies of infliximab and its biosimilar (CT-P13).

    Science.gov (United States)

    Kim, Ji Soo; Kim, Sung Hwan; Kwon, ByoungOh; Hong, SeungSuh

    2015-01-01

    Anti-drug antibodies against biologic drugs affect efficacy and safety; therefore, it is important to use appropriate assays for immunogenicity testing in clinical studies. This review describes the electrochemiluminescent (ECL) immunoassay, ELISA, radioimmunoassay, and homogeneous mobility shift assay. The characteristics of ECL, used to assess immunogenicity in comparison trials of CT-P13 (Remsima(®), Inflectra(®)) versus its reference medicinal product, infliximab (Remicade(®)), are also compared with the other assays, based on published literature. These comparisons show that ECL is more sensitive than ELISA, radioimmunoassay, and homogeneous mobility shift assay, and less affected by drug interference than ELISA. Similar immunogenicity was observed for CT-P13 and reference medicinal product using ECL, demonstrating the reliability of this method to assess immunogenicity in comparative studies.

  3. {sup 68}Ga-DOTATATE PET/CT in recurrent medullary thyroid carcinoma: a lesion-by-lesion comparison with {sup 111}In-octreotide SPECT/CT and conventional imaging

    Energy Technology Data Exchange (ETDEWEB)

    Yamaga, Lilian Yuri Itaya; Cunha, Marcelo L.; Campos Neto, Guilherme C.; Garcia, Marcio R.T.; Wagner, Jairo; Funari, Marcelo B.G. [Hospital Israelita Albert Einstein, Imaging Department, Sao Paulo (Brazil); Yang, Ji H.; Camacho, Cleber P. [Universidade Federal de Sao Paulo, Multiple Neoplasia Outpatiet Clinic, Sao Paulo (Brazil)

    2017-09-15

    The aim of this study was to prospectively compare the detection rate of {sup 68}Ga-DOTATATE PET-CT with {sup 111}In-octreotide SPECT-CT and conventional imaging (CI) in medullary thyroid carcinoma (MTC) patients with increased calcitonin (Ctn) levels but negative CI after thyroidectomy. Fifteen patients with raised Ctn levels and/or CI evidence of recurrence underwent {sup 68}Ga-DOTATATE PET-CT, {sup 111}In-octreotide SPECT-CT and CI. Histopathology, CI and biochemical/clinical/imaging follow-up were used as the reference standard. PET/CT, SPECT/CT and CI were compared in a lesion-based and organ-based analysis. PET/CT evidenced recurrence in 14 of 15 patients. There were 13 true positive (TP), 1 true negative (TN), 1 false positive (FP) and no false negative (FN) cases, resulting in a sensitivity and accuracy of 100% and 93%. SPECT/CT was positive in 6 of 15 cases. There were 6 TP, 2 TN, 7 FN and no FP cases, resulting in a sensitivity of 46% and accuracy of 53%. CI procedures detected tumor lesions in 14 of 15 patients. There were 13 TP, 1TN, 1 FP and no FN cases with a sensitivity of 100% and accuracy of 93%. A significantly higher number of lesions was detected by PET/CT (112 lesions, p = 0.005) and CI (109 lesions, p = 0.005) in comparison to SPECT/CT (16 lesions). There was no significant difference between PET/CT and CI for the total number of detected lesions (p = 0.734). PET/CT detected more lesions than SPECT/CT regardless of the organ. PET/CT detected more bone lesions but missed some neck nodal metastases evidenced by CI. The number of lesions per region demonstrated by PET/CT and CI were similar in the other sites. {sup 68}Ga-DOTATATE PET/CT is superior to {sup 111}In-octreotide SPECT/CT for the detection of recurrent MTC demonstrating a significantly higher number of lesions. {sup 68}Ga-DOTATATE PET/CT showed a superior detection rate compared to CI in demonstrating bone metastases. (orig.)

  4. Effects of multiple-helicity fields on ion temperature gradient modes

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, T. [National Inst. for Fusion Science, Toki, Gifu (Japan); Sugama, H. [Graduate Univ. for Advanced Studies, Toki, Gigu (Japan)

    2001-04-01

    Effects of multiple-helicity magnetic fields on ion temperature gradient (ITG) modes in toroidal helical systems like the Large Helical Device (LHD) are studied by means of the linear gyrokinetic theory. Especially, dependence of the real frequency, growth rate, and the eigenfunction of the ITG mode on sideband-helicity fields added to the main helical component is investigated. Comparison between multiple-helicity effects on the ITG mode with those on the neoclassical ripple transport is presented, and optimization of the magnetic configuration for better plasma confinement is discussed. (author)

  5. Comparison of CT Fluoroscopy-Guided Manual and CT-Guided Robotic Positioning System for In Vivo Needle Placements in Swine Liver

    Energy Technology Data Exchange (ETDEWEB)

    Cornelis, F.; Takaki, H. [Memorial Sloan-Kettering Cancer Center, Interventional Radiology Service, Department of Radiology (United States); Laskhmanan, M. [Perfint Healthcare Inc (India); Durack, J. C.; Erinjeri, J. P.; Getrajdman, G. I.; Maybody, M.; Sofocleous, C. T.; Solomon, S. B.; Srimathveeravalli, G., E-mail: srimaths@mskcc.org [Memorial Sloan-Kettering Cancer Center, Interventional Radiology Service, Department of Radiology (United States)

    2015-10-15

    PurposeTo compare CT fluoroscopy-guided manual and CT-guided robotic positioning system (RPS)-assisted needle placement by experienced IR physicians to targets in swine liver.Materials and MethodsManual and RPS-assisted needle placement was performed by six experienced IR physicians to four 5 mm fiducial seeds placed in swine liver (n = 6). Placement performance was assessed for placement accuracy, procedure time, number of confirmatory scans, needle manipulations, and procedure radiation dose. Intra-modality difference in performance for each physician was assessed using paired t test. Inter-physician performance variation for each modality was analyzed using Kruskal–Wallis test.ResultsPaired comparison of manual and RPS-assisted placements to a target by the same physician indicated accuracy outcomes was not statistically different (manual: 4.53 mm; RPS: 4.66 mm; p = 0.41), but manual placement resulted in higher total radiation dose (manual: 1075.77 mGy/cm; RPS: 636.4 mGy/cm; p = 0.03), required more confirmation scans (manual: 6.6; RPS: 1.6; p < 0.0001) and needle manipulations (manual: 4.6; RPS: 0.4; p < 0.0001). Procedure time for RPS was longer than manual placement (manual: 6.12 min; RPS: 9.7 min; p = 0.0003). Comparison of inter-physician performance during manual placement indicated significant differences in the time taken to complete placements (p = 0.008) and number of repositions (p = 0.04) but not in other study measures (p > 0.05). Comparison of inter-physician performance during RPS-assisted placement suggested statistically significant differences in procedure time (p = 0.02) and not in other study measures (p > 0.05).ConclusionsCT-guided RPS-assisted needle placement reduced radiation dose, number of confirmatory scans, and needle manipulations when compared to manual needle placement by experienced IR physicians, with equivalent accuracy.

  6. Evaluation of dose reduction and image quality in CT colonography: Comparison of low-dose CT with iterative reconstruction and routine-dose CT with filtered back projection

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, Koichi [Kameda Medical Center, Department of Radiology, Kamogawa, Chiba (Japan); Jichi Medical University, Department of Radiology, Tochigi (Japan); National Cancer Center, Cancer Screening Technology Division, Research Center for Cancer Prevention and Screening, Tokyo (Japan); Fujiwara, Masanori; Mogi, Tomohiro; Iida, Nao [Kameda Medical Center Makuhari, Department of Radiology, Chiba (Japan); Kanazawa, Hidenori; Sugimoto, Hideharu [Jichi Medical University, Department of Radiology, Tochigi (Japan); Mitsushima, Toru [Kameda Medical Center Makuhari, Department of Gastroenterology, Chiba (Japan); Lefor, Alan T. [Jichi Medical University, Department of Surgery, Tochigi (Japan)

    2015-01-15

    To prospectively evaluate the radiation dose and image quality comparing low-dose CT colonography (CTC) reconstructed using different levels of iterative reconstruction techniques with routine-dose CTC reconstructed with filtered back projection. Following institutional ethics clearance and informed consent procedures, 210 patients underwent screening CTC using automatic tube current modulation for dual positions. Examinations were performed in the supine position with a routine-dose protocol and in the prone position, randomly applying four different low-dose protocols. Supine images were reconstructed with filtered back projection and prone images with iterative reconstruction. Two blinded observers assessed the image quality of endoluminal images. Image noise was quantitatively assessed by region-of-interest measurements. The mean effective dose in the supine series was 1.88 mSv using routine-dose CTC, compared to 0.92, 0.69, 0.57, and 0.46 mSv at four different low doses in the prone series (p < 0.01). Overall image quality and noise of low-dose CTC with iterative reconstruction were significantly improved compared to routine-dose CTC using filtered back projection. The lowest dose group had image quality comparable to routine-dose images. Low-dose CTC with iterative reconstruction reduces the radiation dose by 48.5 to 75.1 % without image quality degradation compared to routine-dose CTC with filtered back projection. (orig.)

  7. Head-to-head comparison of 68Ga-PSMA-11 PET/CT and 18F-Fluciclovine PET/CT in a case series of 10 patients with prostate cancer recurrence.

    Science.gov (United States)

    Calais, Jeremie; Fendler, Wolfgang P; Herrmann, Ken; Eiber, Matthias; Ceci, Francesco

    2017-12-14

    Purpose: This is a head-to-head comparison between Gallium-68 Prostate Specific Membrane Antigen (68Ga-PSMA-11) and 18F-Fluciclovine Positron Emission Tomography/Computed Tomography (PET/CT) in a series of 10 patients with prostate cancer (PCa) recurrence. Methods: 288 patients with PCa recurrence were enrolled in a prospective study of 68Ga-PSMA-11 PET/CT imaging for recurrent disease localization (NCT02940262). We retrospectively identified 10 patients who underwent clinical indicated 18F-Fluciclovine PET/CT prior enrollment. Results: The median time between both scans was 2.3 months (range 0.2-4.2). The median PSA value was 1.0 ng/ml (mean 4.7 ng/ml; range 0.13-18.1) and 1.1 ng/ml (mean 6.2 ng/ml; range 0.24-31.3) at the time of 18F-Fluciclovine and 68Ga-PSMA-11 PET/CT, respectively. 5/10 patients (50%) were negative on 18F-Fluciclovine PET/CT but showed positive results on 68Ga-PSMA-11 PET/CT. 2/10 patients (20%) had both positive 18F-Fluciclovine and 68Ga-PSMA-11 PET/CT but 68Ga-PSMA-11 PET/CT showed additional lymph nodes (LN) metastasis. 3/10 patients (30%) had both negative 18F-Fluciclovine and 68Ga-PSMA-11 PET/CT. Conclusion: This case series suggests superior detection rate of 68Ga-PSMA-11 PET/CT than 18F-Fluciclovine PET/CT in recurrent PCa. Prospective trials designed to directly compare 68Ga-PSMA-11 and 18F-Fluciclovine PET/CT should be initiated. Copyright © 2017 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  8. Ileoanal pouches: Comparison of CT, scintigraphy, and contrast enemas for diagnosing postsurgical complications

    Energy Technology Data Exchange (ETDEWEB)

    Thoeni, R.F.; Fell, S.C.; Engelstad, B.; Schrock, T.B. (Univ. of California, San Francisco (USA))

    1990-01-01

    The value of CT of the pelvis, 111In-labeled leukocyte scintigraphy, and contrast enema (pouchography) for detecting postsurgical complications was assessed in 44 patients with total colectomy, rectal mucosectomy, and ileoanal pouches. Ileoanal pouches were created as reservoirs from an ileal loop that was anastomosed to the dentate line of the anus and stayed connected to the remainder of the ileum. This pouch preserves the normal defecatory pathway and eliminates disease-producing mucosa. A total of 57 sets of examinations revealed 22 cases of normal postoperative findings, 22 of pouchitis, 13 of abscess, and three of fistula. Overall sensitivity for detecting complications with pouchography was 60% (18 of 30 findings); with CT, 78% (28 of 36 findings); and with scintigraphy, 79% (23 of 29 findings). Pouchitis was best diagnosed by scintigraphy (sensitivity, 80%), followed by CT (sensitivity, 71%) and pouchography (sensitivity, 53%). Only CT correctly diagnosed all cases of abscess. Fistulas were frequently missed by all three methods. If tests were combined, the overall sensitivity rose to 93% for the combination CT/scintigraphy and to 86% for CT/pouchography, but did not improve for pouchography/scintigraphy (78%). For evaluation of complications in patients with ileoanal pouches, CT should be the initial test. If an abscess is found, no further tests are needed. If CT findings are negative, a scintigram should be obtained. Our data did not establish a clear role for pouchography.

  9. Comparison of Three English-to-Dutch Machine Translations of SNOMED CT Procedures

    NARCIS (Netherlands)

    Cornet, Ronald; Hill, Carly; de Keizer, Nicolette

    2017-01-01

    Dutch interface terminologies are needed to use SNOMED CT in the Netherlands. Machine translation may support in their creation. The aim of our study is to compare different machine translations of procedures in SNOMED CT. Procedures were translated using Google Translate, Matecat, and Thot. Google

  10. Comparison of spiral CT angiography vs digital subtraction angiography in the evaluation of living kidney donors

    Directory of Open Access Journals (Sweden)

    Santosh Kumar

    2002-01-01

    Full Text Available Recent reports suggest that spiral computed tomographic (CT angiography could replace conventional angiogra-phy and intravenous urography (IVU for the assessment of potential live kidney donors. The purpose of this study was to assess the accuracy of spiral CT in kidney donor workup. 10 consecutive renal donors had IVU, percutane-ous transfemoral selective renal angiography and spiral CT angiography between January and March 2001. The spiral CT and renal angiograms were assessed independ-ently by two radiologists. The number of renal arteries, pres-ence or absence of renal artery stenoses and associated parenchymal abnormalities were assessed. A total of 27 renal arteries were detected. Transverse scans viewed in a tine loop format with maximum intensity projection and shaded surface display detected all 27 vessels. All 27 ves-sels were detected by conventional catheter angiography. A simple renal cyst was noted in both spiral CT and con-ventional angiogram. Venous anatomy including a retroaortic renal vein was visualized in spiral CT angiogram but not visualized by conventional angiography. Spiral CT angiography performed as an outpatient procedure is less invasive, less expensive, and provides good images of the arterial and venous anatomy in addition to the visualiza-tion of the other abdominal viscera. A plain X-ray of the abdomen was taken 15 rains after injection of contrast to acquire an IVU like image. Spiral CT angiography has the potential to replace conventional catheter angiography and IVU in the assessment of renal donors.

  11. Inter-laboratory comparison of medical computed tomography (CT) scanners for industrial applications in the slaughterhouses

    DEFF Research Database (Denmark)

    Christensen, Lars Bager; Angel, Jais Andreas Breusch

    2013-01-01

    Using computed tomography (CT) in the calibration of online grading equipment has been demonstrated to be beneficial over the last years by several institutions using medical CT scanners. The difference in makes and models calls for a standardized (and calibrated) method to be able to quantify di...

  12. Assessment of CF lung disease using motion corrected PROPELLER MRI: a comparison with CT

    Energy Technology Data Exchange (ETDEWEB)

    Ciet, Pierluigi [General Hospital Ca' Foncello, Radiology Department, Treviso (Italy); Sophia Children' s Hospital, Pediatric Pulmonology Erasmus MC, Rotterdam (Netherlands); Erasmus MC, Radiology, Rotterdam (Netherlands); Serra, Goffredo; Catalano, Carlo [University of Rome ' ' Sapienza' ' , Radiology, Rome (Italy); Bertolo, Silvia; Morana, Giovanni [General Hospital Ca' Foncello, Radiology Department, Treviso (Italy); Spronk, Sandra [Erasmus MC, Radiology, Rotterdam (Netherlands); Erasmus MC, Epidemiology, Rotterdam (Netherlands); Ros, Mirco [Ca' Foncello Hospital, Pediatrics, Treviso (Italy); Fraioli, Francesco [University College London (UCL), Institute of Nuclear Medicine, London (United Kingdom); Quattrucci, Serena [University of Rome Sapienza, Pediatrics, Rome (Italy); Assael, M.B. [Azienda Ospedaliera di Verona, Verona CF Center, Verona (Italy); Pomerri, Fabio [University of Padova, Department of Medicine-DIMED, Padova (Italy); Tiddens, Harm A.W.M. [Sophia Children' s Hospital, Pediatric Pulmonology Erasmus MC, Rotterdam (Netherlands); Erasmus MC, Radiology, Rotterdam (Netherlands)

    2016-03-15

    To date, PROPELLER MRI, a breathing-motion-insensitive technique, has not been assessed for cystic fibrosis (CF) lung disease. We compared this technique to CT for assessing CF lung disease in children and adults. Thirty-eight stable CF patients (median 21 years, range 6-51 years, 22 female) underwent MRI and CT on the same day. Study protocol included respiratory-triggered PROPELLER MRI and volumetric CT end-inspiratory and -expiratory acquisitions. Two observers scored the images using the CF-MRI and CF-CT systems. Scores were compared with intra-class correlation coefficient (ICC) and Bland-Altman plots. The sensitivity and specificity of MRI versus CT were calculated. MRI sensitivity for detecting severe CF bronchiectasis was 0.33 (CI 0.09-0.57), while specificity was 100 % (CI 0.88-1). ICCs for bronchiectasis and trapped air were as follows: MRI-bronchiectasis (0.79); CT-bronchiectasis (0.85); MRI-trapped air (0.51); CT-trapped air (0.87). Bland-Altman plots showed an MRI tendency to overestimate the severity of bronchiectasis in mild CF disease and underestimate bronchiectasis in severe disease. Motion correction in PROPELLER MRI does not improve assessment of CF lung disease compared to CT. However, the good inter- and intra-observer agreement and the high specificity suggest that MRI might play a role in the short-term follow-up of CF lung disease (i.e. pulmonary exacerbations). (orig.)

  13. Comparison of the Batho, ETAR and Monte Carlo dose calculation methods in CT based patient models.

    Science.gov (United States)

    du Plessis, F C; Willemse, C A; Lötter, M G; Goedhals, L

    2001-04-01

    This paper shows the contribution that Monte Carlo methods make in regard to dose distribution calculations in CT based patient models and the role it plays as a gold standard to evaluate other dose calculation algorithms. The EGS4 based BEAM code was used to construct a generic 8 MV accelerator to obtain a series of x-ray field sources. These were used in the EGS4 based DOSXYZ code to generate beam data in a mathematical water phantom to set up a beam model in a commercial treatment planning system (TPS), CADPLAN V.2.7.9. Dose distributions were calculated with the Batho and ETAR inhomogeneity correction algorithms in head/sinus, lung, and prostate patient models for 2 x 2, 5 x 5, and 10 X 10 cm2 open x-ray beams. Corresponding dose distributions were calculated with DOSXYZ that were used as a benchmark. The dose comparisons are expressed in terms of 2D isodose distributions, percentage depth dose data, and dose difference volume histograms (DDVH's). Results indicated that the Batho and ETAR methods contained inaccuracies of 20%-70% in the maxillary sinus region in the head model. Large lung inhomogeneities irradiated with small fields gave rise to absorbed dose deviations of 10%-20%. It is shown for a 10 x 10 cm2 field that DOSXYZ models lateral scatter in lung that is not present in the Batho and ETAR methods. The ETAR and Batho methods are accurate within 3% in a prostate model. We showed how the performance of these inhomogeneity correction methods can be understood in realistic patient models using validated Monte Carlo codes such as BEAM and DOSXYZ.

  14. Evaluation of dose reduction and image quality in CT colonography: comparison of low-dose CT with iterative reconstruction and routine-dose CT with filtered back projection.

    Science.gov (United States)

    Nagata, Koichi; Fujiwara, Masanori; Kanazawa, Hidenori; Mogi, Tomohiro; Iida, Nao; Mitsushima, Toru; Lefor, Alan T; Sugimoto, Hideharu

    2015-01-01

    To prospectively evaluate the radiation dose and image quality comparing low-dose CT colonography (CTC) reconstructed using different levels of iterative reconstruction techniques with routine-dose CTC reconstructed with filtered back projection. Following institutional ethics clearance and informed consent procedures, 210 patients underwent screening CTC using automatic tube current modulation for dual positions. Examinations were performed in the supine position with a routine-dose protocol and in the prone position, randomly applying four different low-dose protocols. Supine images were reconstructed with filtered back projection and prone images with iterative reconstruction. Two blinded observers assessed the image quality of endoluminal images. Image noise was quantitatively assessed by region-of-interest measurements. The mean effective dose in the supine series was 1.88 mSv using routine-dose CTC, compared to 0.92, 0.69, 0.57, and 0.46 mSv at four different low doses in the prone series (p iterative reconstruction were significantly improved compared to routine-dose CTC using filtered back projection. The lowest dose group had image quality comparable to routine-dose images. Low-dose CTC with iterative reconstruction reduces the radiation dose by 48.5 to 75.1% without image quality degradation compared to routine-dose CTC with filtered back projection. • Low-dose CTC reduces radiation dose ≥ 48.5% compared to routine-dose CTC. • Iterative reconstruction improves overall CTC image quality compared with FBP. • Iterative reconstruction reduces overall CTC image noise compared with FBP. • Automated exposure control with iterative reconstruction is useful for low-dose CTC.

  15. Comparison of Haller index values calculated with chest radiographs versus CT for pectus excavatum evaluation.

    Science.gov (United States)

    Khanna, Geetika; Jaju, Alok; Don, Steven; Keys, Tim; Hildebolt, Charles F

    2010-11-01

    Pectus excavatum is a common chest wall anomaly in children. Pre-operative imaging for pectus excavatum is performed with CT, which is used to calculate the Haller index to determine the severity of pectus excavatum. To determine the correlation between Haller index values calculated with two-view chest radiographs and those calculated with CT and to determine, with CT as the reference standard, the diagnostic performance of radiographic Haller index for identifying cases that meet imaging criteria for surgical correction of pectus excavatum. For the period 2001-2009, our radiology information system was searched to identify all children who had undergone CT for Haller index calculation. Children who had also undergone two-view chest radiography (CXR) within 6 months of the CT were included in this retrospective study. Two radiologists independently calculated CT Haller index and radiographic Haller index. Data distributions were tested for normality with the Shapiro-Wilk W test. The associations between CT Haller index and radiographic Haller index were determined with the Spearman coefficient of rank correlation. Differences between CT Haller index and radiographic Haller index were tested with the Wilcoxon signed rank test. Haller index values were dichotomized into positive (>3.2) and negative (≤3.2) cases. Using CT as the reference standard, the sensitivity, specificity, and accuracy of radiographic Haller index in identifying children who meet imaging criteria for surgery were calculated. CT and CXR for evaluation of pectus excavatum were available for 32 children (25 male; median age 14.5 years). With CT, the median Haller indices for observers 1 and 2 were 3.4 and 3.5 and with CXR 3.5 and 3.5. There were statistically significant correlations between the radiographic Haller index and CT Haller index estimated by the two observers [Spearman correlation coefficient (95% confidence interval) for observer 1 = 0.71 (0.48-0.85, P pectus excavatum. We

  16. Relationship between the CT Value and Cortical Bone Thickness at Implant Recipient Sites and Primary Implant Stability with Comparison of Different Implant Types.

    Science.gov (United States)

    Howashi, Miori; Tsukiyama, Yoshihiro; Ayukawa, Yasunori; Isoda-Akizuki, Kei; Kihara, Masafumi; Imai, Yu; Sogo, Motofumi; Koyano, Kiyoshi

    2016-02-01

    Studies have shown that bone quality at the implant recipient site can influence primary stability. The aims of this study were to explore the quantitative estimation of the primary stability of implants preoperatively using CT values and to examine the effect of different implant designs with recommended socket preparation on primary stability. Forty-four fresh porcine femoral heads were prepared. The bone surrounding implant sockets was preoperatively evaluated by helical CT. Forty-four implants (φ 4.3 × 10 mm), 22 straight and 22 tapered, were placed according to the manufacturer's instructions. The insertion torque value (ITV), implant stability quotient (ISQ), and removal torque value (RTV) were recorded as indicators of primary implant stability. Significant correlations and linear relationships were found between the CT value and ITV, ISQ, and RTV for both straight and tapered implants (Spearman's correlation coefficient, p < .001; linear regression analysis, p < .01). Tapered implants had a significantly higher ITV than straight implants (analysis of covariance, p < .01). Obtained results suggest that the primary stability of implants could be quantitatively estimated using the CT value preoperatively, indicating the CT value of bone surrounding an implant can contribute considerably to implant planning and design choice in clinical situations. © 2014 Wiley Periodicals, Inc.

  17. Large Helical Device project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-05-01

    In this book, the results of the scientific research on the design, trial manufacture and manufacturing processes of the Large Helical Device which was constructed in National Institute for Fusion Science are summarized. The LHD is the largest helical device in the world, and the largest superconducting system in the world. It possesses the following features: the optimization of heliotron magnetic field coordination, the adoption of superconducting magnets for 2 helical magnetic field coils and 6 poloidal coils, the adoption of helical diverter which enables steady plasma experiment, the flexible specification as the experimental facility and so on. The construction has been carried out smoothly, and in March, 1998, first plasma was generated. The outline of the Large Helical Device project, the physical design, the equipment design, the research and development of superconductivity and low temperature system, the design and manufacture of the superconducting and low temperature systems, the design and manufacture of the power source and superconducting bus-line, vacuum vessel and others, electron cyclotron heating, neutral beam injection and ion cyclotron RF heating, measurement system, control and data processing, safety management, the theory and analysis of LHD plasma, the visualization of the result of theoretical analysis, the analysis of the experimental data, and the experiment plan are described. (K.I.)

  18. PET/MRI and PET/CT in advanced gynaecological tumours: initial experience and comparison

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Marcelo A.; Schulthess, Gustav von; Veit-Haibach, Patrick [University Hospital Zurich, Department Medical Radiology, Nuclear Medicine, Zurich (Switzerland); University Hospital Zurich, Department Medical Radiology, Diagnostic and Interventional Radiology, Zurich (Switzerland); University of Zurich, Zurich (Switzerland); Kubik-Huch, Rahel A.; Freiwald-Chilla, Bianka [Kantonsspital Baden AG, Department of Radiology, Baden (Switzerland); Hauser, Nik [Kantonsspital Baden AG, Department of Gynaecology, Baden (Switzerland); Froehlich, Johannes M. [Guerbet AG, Zurich (Switzerland)

    2015-08-15

    To compare the diagnostic accuracy of PET/MRI and PET/CT for staging and re-staging advanced gynaecological cancer patients as well as identify the potential benefits of each method in such a population. Twenty-six patients with suspicious or proven advanced gynaecological cancer (12 ovarian, seven cervical, one vulvar and four endometrial tumours, one uterine metastasis, and one primary peritoneal cancer) underwent whole-body imaging with a sequential trimodality PET/CT/MR system. Images were analysed regarding primary tumour detection and delineation, loco-regional lymph node staging, and abdominal/extra-abdominal distant metastasis detection (last only by PET/CT). Eighteen (69.2 %) patients underwent PET/MRI for primary staging and eight patients (30.8 %) for re-staging their gynaecological malignancies. For primary tumour delineation, PET/MRI accuracy was statistically superior to PET/CT (p < 0.001). Among the different types of cancer, PET/MRI presented better tumour delineation mainly for cervical (6/7) and endometrial (2/3) cancers. PET/MRI for local evaluation as well as PET/CT for extra-abdominal metastases had therapeutic consequences in three and one patients, respectively. PET/CT detected 12 extra-abdominal distant metastases in 26 patients. PET/MRI is superior to PET/CT for primary tumour delineation. No differences were found in detection of regional lymph node involvement and abdominal metastases detection. (orig.)

  19. A single institution study of radiation dose received from CT imaging: A comparison to Malaysian NDRL

    Science.gov (United States)

    Osman, N. D.; Shamsuri, S. B. M.; Tan, Y. W.; Razali, M. A. S. M.; Isa, S. M.

    2017-05-01

    Advancement of CT technology has led to an increase in CT scanning as it improves the diagnosis. However, it is important to assess health risk of patients associated with ionising radiation received from CT. This study evaluated current dose distributions at Advanced Medical and Dental Institute (AMDI), Malaysia and was used to establish Local Diagnostic Reference Level (LDRL). Dose indicators such as CT Dose Index (CTDIvol and CTDIw) and Dose-Length Product (DLP) were gathered for all routine CT examinations performed at the Imaging Unit, AMDI from January 2015 to June 2016. The first and third quartile values for each dose indicator were determined. A total of 364 CT studies were performed during that period with the highest number of cases being Thorax-Abdomen-Pelvis (TAP) study (57% of total study). The CTDIw ranged between 2.0 mGy to 23.4 mGy per procedure. DLP values were ranged between 94 mGy.cm to 1687 mGy.cm. The local dose data was compared with the national DRL to monitor the current CT practice at AMDI and LDRL will be established from the calculated third quartile values of dose distribution. From the results, some of the local dose values exceeded the Malaysian and further evaluation is important to ensure the dose optimisation for patients.

  20. Comparison of CT and MRI for diagnosis of advanced thyroid cancer with invasion to adjacent organs

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Hajime; Sako, Hirotaka; Umeda, Tomoko; Kodama, Masashi [Shiga Univ. of Medical Science, Otsu (Japan)

    1994-12-01

    In 20 cases of advanced thyroid cancer, computed tomography (CT) and magnetic resonance imaging (MRI) were compared for their ability to identify invasion to adjacent organs. CT revealed invasion in 2 of 3 cases of tracheal invasion, which was later confirmed by surgery, whereas MRI revealed invasion in all 3 cases. No cases of carotid artery invasion were recognized by CT, MRI or surgery. For invasion of the jugular vein, 4 of 20 cases were confirmed by surgery. CT showed obliteration of the fat plane in 5 cases and MRI showed invasion in all 3 cases for which it was performed. Of 4 cases of esophageal invasion, CT revealed this in 2, and MRI revealed invasion in 2 of the 3 cases for which it was performed. Among 6 cases of neural invasion, CT demonstrated invasion in only 1 whereas MRI demonstrated it in 3 of 5 cases for which it was performed. In conclusion, MRI seems more useful than CT for diagnosis of invasion to adjacent organs in cases of advanced thyroid cancer because of minimal artifacts and the demonstration of distinct boundaries between adjacent organs. (author).

  1. Diagnosing and staging of cystic echinococcosis: how do CT and MRI perform in comparison to ultrasound?

    Directory of Open Access Journals (Sweden)

    Marija Stojkovic

    Full Text Available BACKGROUND: Imaging plays the key role in diagnosing and staging of CE. The description of CE-specific imaging features and the WHO CE cyst classification is based on ultrasound. The reproducibility of the ultrasound-defined features of CE cysts is variable in MR- and CT-imaging. This is of particular importance for cysts that are not accessible by US and because of the increasing availability and overuse of CT and MR imaging. METHODOLOGY/PRINCIPAL FINDINGS: Retrospective analysis of patients with abdominal CE cysts of an interdisciplinary CE clinic who had CT and/or MRI scans performed additionally to US imaging. All images were read and interpreted by the same senior radiologist experienced in the diagnosis of CE. US, CT and MR images were staged according to the WHO classification criteria. The agreement beyond chance was quantified by kappa coefficients (κ. 107 patients with 187 CE cysts met the inclusion criteria. All cysts were assessed by US, 138 by CT, and 125 by MRI. The level of agreement beyond chance of the individual CE stages 1-4 was clearly lower for CT, with κ ranging from 0.62 to 0.72, compared to MRI with values of κ between 0.83 and 1.0. For CE5 cysts CT (κ = 0.95 performed better than MRI (κ = 0.65. CONCLUSIONS: Ultrasound remains the corner stone of diagnosis, staging and follow up of CE cysts. MRI reproduces the ultrasound-defined features of CE better than CT. If US cannot be performed due to cyst location or patient-specific reasons MRI with heavily T2-weighted series is preferable to CT.

  2. Helical plasma thruster

    Energy Technology Data Exchange (ETDEWEB)

    Beklemishev, A. D., E-mail: bekl@bk.ru [Budker Institute of Nuclear Physics SB RAS, Novosibirsk (Russian Federation)

    2015-10-15

    A new scheme of plasma thruster is proposed. It is based on axial acceleration of rotating magnetized plasmas in magnetic field with helical corrugation. The idea is that the propellant ionization zone can be placed into the local magnetic well, so that initially the ions are trapped. The E × B rotation is provided by an applied radial electric field that makes the setup similar to a magnetron discharge. Then, from the rotating plasma viewpoint, the magnetic wells of the helically corrugated field look like axially moving mirror traps. Specific shaping of the corrugation can allow continuous acceleration of trapped plasma ions along the magnetic field by diamagnetic forces. The accelerated propellant is expelled through the expanding field of magnetic nozzle. By features of the acceleration principle, the helical plasma thruster may operate at high energy densities but requires a rather high axial magnetic field, which places it in the same class as the VASIMR{sup ®} rocket engine.

  3. Duplex ultrasonography for the detection of vertebral artery stenosis A comparison with CT angiography

    NARCIS (Netherlands)

    Rozeman, Anouk D.; Hund, Hajo; Westein, Michel; Wermer, Marieke J H; Nijeholt, Geert J. Lycklama A.; Boiten, Jelis; Schimsheimer, Robert-Jan; Algra, Ale

    Objectives Vertebrobasilar stenosis is frequent in patients with posterior circulation stroke and it increases risk of recurrence. We investigated feasibility of duplex ultrasonography (DUS) for screening for extracranial vertebral artery stenosis and compared it with CT angiography (CTA). Materials

  4. Semicircular canal dehiscence: comparison of T2-weighted turbo spin-echo MRI and CT

    Energy Technology Data Exchange (ETDEWEB)

    Krombach, G.A.; Schmitz-Rode, T.; Haage, P.; Guenther, R.W. [Department of Diagnostic Radiology, University of Technology, Pauwelstrasse 30, 52057, Aachen (Germany); DiMartino, E. [Department of Otorhinolaryngology, University of Technology, Pauwelstrasse 30, 52057, Aachen (Germany); Prescher, A. [Department of Anatomy, University of Technology, Pauwelstrasse 30, 52057, Aachen (Germany); Kinzel, S. [Department of Experimental Veterinary Medicine, University of Technology, Pauwelstrasse 30, 52057, Aachen (Germany)

    2004-04-01

    We assessed the value of MRI for delineation of dehiscence of the superior or posterior semicircular canal, as compared with CT, the current standard study for this entity. We reviewed heavily T2-weighted fast spin-echo images and high-resolution CT of the temporal bones of 185 patients independently semicircular canal dehiscence and its extent. In 30 patients (19 men, 11 women) we identified dehiscence of the bone over the superior and/or posterior semicircular canal on MRI. In 27 of these cases CT also showed circumscribed bone defects. In one patient dehiscence of the superior semicircular canal was initially overlooked on MRI, but seen on CT. MRI imaging thus had a sensitivity of 96% and specificity of 98%. Knowledge of the appearances of this entity on MRI may contribute to early diagnosis in patients with vertigo due to semicircular canal dehiscence. (orig.)

  5. Comparison of MRI- and CT-based semiautomated liver segmentation: a validation study.

    Science.gov (United States)

    Gotra, Akshat; Chartrand, Gabriel; Vu, Kim-Nhien; Vandenbroucke-Menu, Franck; Massicotte-Tisluck, Karine; de Guise, Jacques A; Tang, An

    2017-02-01

    To compare the repeatability, agreement, and efficiency of MRI- and CT-based semiautomated liver segmentation for the assessment of total and subsegmental liver volume. This retrospective study was conducted in 31 subjects who underwent contemporaneous liver MRI and CT. Total and subsegmental liver volumes were segmented from contrast-enhanced 3D gradient-recalled echo MRI sequences and CT images. Semiautomated segmentation was based on variational interpolation and Laplacian mesh optimization. All segmentations were repeated after 2 weeks. Manual segmentation of CT images using an active contour tool was used as the reference standard. Repeatability and agreement of the methods were evaluated with intra-class correlation coefficients (ICC) and Bland-Altman analysis. Total interaction time was recorded. Intra-reader ICC were ≥0.987 for MRI and ≥0.995 for CT. Intra-reader repeatability was 30 ± 217 ml (bias ± 1.96 SD) (95% limits of agreement: -187 to 247 ml) for MRI and -10 ± 143 ml (-153 to 133 ml) for CT. Inter-method ICC between semiautomated and manual volumetry were ≥0.995 for MRI and ≥0.986 for CT. Inter-method segmental ICC varied between 0.584 and 0.865 for MRI and between 0.596 and 0.890 for CT. Inter-method agreement was -14 ± 136 ml (-150 to 122 ml) for MRI and 50 ± 226 ml (-176 to 276 ml) for CT. Inter-method segmental agreement ranged from 10 ± 47 ml (-37 to 57 ml) to 2 ± 214 ml (-212 to 216 ml) for MRI and 9 ± 45 ml (-36 to 54 ml) to -46 ± 183 ml (-229 to 137 ml) for CT. Interaction time (mean ± SD) was significantly shorter for MRI-based semiautomated segmentation (7.2 ± 0.1 min, p segmentation (6.5 ± 0.2 min, p segmentation (14.5 ± 0.4 min). MRI-based semiautomated segmentation provides similar repeatability and agreement to CT-based segmentation for total liver volume.

  6. MRI-guided and CT-guided cervical nerve root infiltration therapy. A cost comparison

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, M.H.; Froeling, V.; Roettgen, R.; Bucourt, M. de; Hamm, B.; Streitparth, F. [Charite University Medicine Berlin (Germany). Dept. of Diagnostic and Interventional Radiology; Bretschneider, T. [Magdeburg Univ. (Germany). Dept. of Radiology and Nuclear Medicine; Hartwig, T.; Disch, A.C. [Charite University Medicine Berlin (Germany). Center for Musculoskeletal Surgery

    2014-06-15

    Purpose: To evaluate and compare the costs of MRI-guided and CT-guided cervical nerve root infiltration for the minimally invasive treatment of radicular neck pain. Materials and Methods: Between September 2009 and April 2012, 22 patients (9 men, 13 women; mean age: 48.2 years) underwent MRI-guided (1.0 Tesla, Panorama HFO, Philips) single-site periradicular cervical nerve root infiltration with 40 mg triamcinolone acetonide. A further 64 patients (34 men, 30 women; mean age: 50.3 years) were treated under CT fluoroscopic guidance (Somatom Definition 64, Siemens). The mean overall costs were calculated as the sum of the prorated costs of equipment use (purchase, depreciation, maintenance, and energy costs), personnel costs and expenditure for disposables that were identified for MRI- and CT-guided procedures. Additionally, the cost of ultrasound guidance was calculated. Results: The mean intervention time was 24.9 min. (range: 12-36 min.) for MRI-guided infiltration and 19.7 min. (range: 5-54 min.) for CT-guided infiltration. The average total costs per patient were EUR 240 for MRI-guided interventions and EUR 124 for CT-guided interventions. These were (MRI/CT guidance) EUR 150/60 for equipment use, EUR 46/40 for personnel, and EUR 44/25 for disposables. The mean overall cost of ultrasound guidance was EUR 76. Conclusion: Cervical nerve root infiltration using MRI guidance is still about twice as expensive as infiltration using CT guidance. However, since it does not involve radiation exposure for patients and personnel, MRI-guided nerve root infiltration may become a promising alternative to the CT-guided procedure, especially since a further price decrease is expected for MRI devices and MR-compatible disposables. In contrast, ultrasound remains the less expensive method for nerve root infiltration guidance. (orig.)

  7. Proton MRI in the evaluation of pulmonary sarcoidosis: Comparison to chest CT

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Jonathan H., E-mail: chungj@njhealth.org [Radiology, National Jewish Health, Denver, CO (United States); Little, Brent P., E-mail: bplittle2@hotmail.com [Radiology, Emory University School of Medicine, Atlanta, GA (United States); Forssen, Anna V., E-mail: ForssenA@NJHealth.org [Division of Biostatistics and Bioinformatics, National Jewish Health, Denver, CO (United States); Yong, Jin, E-mail: JinG@NJHealth.org [Radiology, National Jewish Health, Denver, CO (United States); Diagnostic Radiology, Chonbuk National University Medical School, Jeonbuk (Korea, Republic of); Nambu, Atsushi, E-mail: nambu-a@gray.plala.or.jp [Radiology, National Jewish Health, Denver, CO (United States); Radiology, University of Yamanashi, Chuo City (Japan); Kazlouski, Demitry, E-mail: demitry.kazlouski@gmail.com [Radiology, National Jewish Health, Denver, CO (United States); Puderbach, Michael, E-mail: m.puderbach@dkfz-heidelberg.de [Diagnostic and Interventional Radiology, Chest Clinics at University Hospital, Heidelberg (Germany); Biederer, Juergen, E-mail: juergen.biederer@uni-heidelberg.de [Diagnostic and Interventional Radiology, Heidelberg University Hospital, Heidelberg (Germany); Lynch, David A., E-mail: LynchD@NJHealth.org [Radiology, National Jewish Health, Denver, CO (United States)

    2013-12-01

    Purpose: The purpose of this study was to determine the feasibility of proton MRI of the lung in sarcoidosis patients and the agreement between the imaging appearance of pulmonary sarcoidosis on MRI and CT. Materials and methods: Chest CT scans and dedicated pulmonary MRI scans (including HASTE, VIBE, and TrueFISP sequences) were performed within 90 days of each other in 29 patients. The scans were scored for gross parenchymal opacification, reticulation, nodules, and masses using a 3-point lobar scale. Total and subset scores for corresponding MRI and CT scans were compared using the Spearman correlation test, Bland–Altman plots, and Cohen's quadratic-weighted kappa analysis. MRI scores were compared to CT by lobe and disease category, using percentage agreement, Spearman rank correlation, and Cohen's quadratic-weighted kappa. Results: The mean (±s.d.) time between MRI and CT scans was 33 ± 32 days. There was substantial correlation and agreement between total disease scoring on MRI and CT with a Spearman correlation coefficient of 0.774 (p < 0.0001) and a Cohen's weighted kappa score of 0.646. Correlation and agreement were highest for gross parenchymal opacification (0.695, 0.528) and reticulation (0.609, 0.445), and lowest in the setting of nodules (0.501, 0.305). Agreement testing was not performed for mass scores due to low prevalence. Upper lobe scoring on MRI and CT demonstrated greater agreement compared to the lower lobes (average difference in Cohen's weighted kappa score of 0.112). Conclusion: There is substantial correlation and agreement between MRI and CT in the scoring of pulmonary sarcoidosis, though MRI evaluation in the upper lobes may be more accurate than in the lower lobes.

  8. Evaluating the accuracy of 4D-CT ventilation imaging: First comparison with Technegas SPECT ventilation.

    Science.gov (United States)

    Hegi-Johnson, Fiona; Keall, Paul; Barber, Jeff; Bui, Chuong; Kipritidis, John

    2017-08-01

    Computed tomography ventilation imaging (CTVI) is a highly accessible functional lung imaging modality that can unlock the potential for functional avoidance in lung cancer radiation therapy. Previous attempts to validate CTVI against clinical ventilation single-photon emission computed tomography (V-SPECT) have been hindered by radioaerosol clumping artifacts. This work builds on those studies by performing the first comparison of CTVI with 99m Tc-carbon ('Technegas'), a clinical V-SPECT modality featuring smaller radioaerosol particles with less clumping. Eleven lung cancer radiotherapy patients with early stage (T1/T2N0) disease received treatment planning four-dimensional CT (4DCT) scans paired with Technegas V/Q-SPECT/CT. For each patient, we applied three different CTVI methods. Two of these used deformable image registration (DIR) to quantify breathing-induced lung density changes (CTVIDIR-HU ), or breathing-induced lung volume changes (CTVIDIR-Jac ) between the 4DCT exhale/inhale phases. A third method calculated the regional product of air-tissue densities (CTVIHU ) and did not involve DIR. Corresponding CTVI and V-SPECT scans were compared using the Dice similarity coefficient (DSC) for functional defect and nondefect regions, as well as the Spearman's correlation r computed over the whole lung. The DIR target registration error (TRE) was quantified using both manual and computer-selected anatomic landmarks. Interestingly, the overall best performing method (CTVIHU ) did not involve DIR. For nondefect regions, the CTVIHU , CTVIDIR-HU , and CTVIDIR-Jac methods achieved mean DSC values of 0.69, 0.68, and 0.54, respectively. For defect regions, the respective DSC values were moderate: 0.39, 0.33, and 0.44. The Spearman r-values were generally weak: 0.26 for CTVIHU , 0.18 for CTVIDIR-HU , and -0.02 for CTVIDIR-Jac . The spatial accuracy of CTVI was not significantly correlated with TRE, however the DIR accuracy itself was poor with TRE > 3.6 mm on average

  9. Metastatic retropharyngeal lymph nodes: Comparison of CT and MR imaging for diagnostic accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Hiroki, E-mail: hkato@gifu-u.ac.jp [Department of Radiology, Gifu University School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan); Kanematsu, Masayuki, E-mail: masa_gif@yahoo.co.jp [Department of Radiology, Gifu University School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan); High-level Imaging Diagnosis Center, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194 (Japan); Watanabe, Haruo, E-mail: haruwow860@yahoo.co.jp [Department of Radiology, Gifu University School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan); Mizuta, Keisuke, E-mail: kmizuta@gifu-u.ac.jp [Department of Otolaryngology, Gifu University School of Medicine, Gifu (Japan); Aoki, Mitsuhiro, E-mail: aoki@gifu-u.ac.jp [Department of Otolaryngology, Gifu University School of Medicine, Gifu (Japan)

    2014-07-15

    Purpose: The purpose of this study was to compare the diagnostic accuracies of CT and MR imaging for the detection of metastatic retropharyngeal lymph nodes (RLNs) in patients with nasopharyngeal and oropharyngeal squamous cell carcinoma (SCC). Materials and methods: The study included 38 patients (28 men and 10 women; mean age, 65 years; age range, 48–82 years) with nasopharyngeal (n = 15) and oropharyngeal (n = 23) SCC who underwent both contrast-enhanced CT and MR imaging before chemoradiotherapy. RLNs were classified as malignant or benign on the basis of the results of follow-up MR imaging. Two radiologists independently evaluated the images for diagnosing metastatic RLNs. Results: Among a total of 68 RLNs (minimum diameter, ≥4 mm) that were detected on gadolinium-enhanced fat-suppressed T1-weighted images, 30 (44%) were malignant and 38 (56%) were benign. The sensitivities of CT versus MRI were 60% versus 97% for observer 1 (p < 0.01) and 37% versus 90% for observer 2 (p < 0.01). The specificities of CT versus MRI were 92% versus 97% for observer 1 (p = 0.50) and 92% versus 100% for observer 2 (p = 0.25). The areas under the receiver operating characteristic curve (AUC) for CT versus MRI were 0.788 versus 0.996 for observer 1 (p < 0.01) and 0.693 versus 0.961 for observer 2 (p < 0.01). Conclusion: MR imaging was superior to CT for the detection of metastatic RLNs.

  10. Obscure gastrointestinal bleeding: preliminary comparison of 64-section CT enteroclysis with video capsule endoscopy

    Energy Technology Data Exchange (ETDEWEB)

    Khalife, Samer; Vahedi, Kouroche; Dray, Xavier; Marteau, Philippe [Hopital Lariboisiere-AP-HP, Universite Diderot-Paris 7, Department of Digestive Diseases, Paris Cedex 10 (France); Soyer, Philippe; Hamzi, Lounis; Place, Vinciane; Boudiaf, Mourad [Hopital Lariboisiere-AP-HP, Universite Diderot-Paris 7, Department of Abdominal Imaging, Paris Cedex 10 (France); Alatawi, Abdullah [Hopital Lariboisiere-AP-HP, Universite Diderot-Paris 7, Department of Digestive Diseases, Paris Cedex 10 (France); Hopital Lariboisiere-AP-HP, Universite Diderot-Paris 7, Department of Abdominal Imaging, Paris Cedex 10 (France)

    2011-01-15

    To retrospectively compare the diagnostic capabilities of 64-section CT enteroclysis with those of video capsule endoscopy (VCE) to elucidate the cause of obscure gastrointestinal bleeding. Thirty-two patients who had 64-section CT enteroclysis and VCE because of obscure gastrointestinal bleeding were included. Imaging findings were compared with those obtained at double balloon endoscopy, surgery and histopathological analysis, which were used as a standard of reference. Concordant findings were found in 22 patients (22/32; 69%), including normal findings (n = 13), tumours (n = 7), lymphangiectasia (n = 1) and inflammation (n = 1), and discrepancies in 10 patients (10/32; 31%), including ulcers (n = 3), angioectasias (n = 2), tumours (n = 2) and normal findings (n = 3). No statistical difference in the proportions of abnormal findings between 64-section CT enteroclysis (11/32; 34%) and VCE (17/32, 53%) (P = 0.207) was found. However, 64-section CT enteroclysis helped identify tumours not detected at VCE (n = 2) and definitely excluded suspected tumours (n = 3) because of bulges at VCE. Conversely, VCE showed ulcers (n = 3) and angioectasias (n = 2) which were not visible at 64-section CT enteroclysis. Our results suggest that 64-section CT enteroclysis and VCE have similar overall diagnostic yields in patients with obscure gastrointestinal bleeding. However, the two techniques are complementary in this specific population. (orig.)

  11. Diverticulitis of the sigmoid colon. A comparison of CT, colonic enema and laparoscopy

    Energy Technology Data Exchange (ETDEWEB)

    Stefansson, T. [Univ. Hospital, Uppsala (Sweden). Dept. of Surgery]|[Univ. Hospital, Uppsala (Sweden). Dept. of Epidemiology; Nyman, R. [Univ. Hospital, Uppsala (Sweden). Dept. of Diagnostic Radiology; Nilsson, S. [Univ. Hospital, Uppsala (Sweden). Dept. of Diagnostic Radiology; Ekbom, A. [Univ. Hospital, Uppsala (Sweden). Dept. of Surgery]|[Univ. Hospital, Uppsala (Sweden). Dept. of Epidemiology; Paahlman, L. [Univ. Hospital, Uppsala (Sweden). Dept. of Surgery

    1997-03-01

    Purpose: To evaluate the use of laparoscopy, CT, colonic enema (CE), and laboratory tests (white blood cell count (WBC), sedimentation rate (SR), and C-reactive protein (CRP)) in diagnosing diverticulitis of the sigmoid colon. Material and Methods: The diagnostic methods were prospectively evaluated in 88 patients, 30 of whom were referred for laparoscopy. Results: Fity-two patients were found to have sigmoid diverticulitis: 20 patients by lanparoscopy, 21 by CT, and 11 by CE combined with one positive laboratory test. Laparoscopy proved to be superior to the other diagnostic methods in diagnosing diverticulitis of the sigmoid colon. CT had a high specificity (1.0; 95% CI: 0.92-1.0) but low sensitivity (0.69; 95% CI: 0.56-0.79) in detecting diverticulitis. CE had a higher sensitivity (0.82; 95% CI: 0.71-0.90) but a lower specificity (0.81; 95% CI: 0.67-0.91) than CT. Conclusion: CT was the best method for diagnosing abdominal pathology outside the colon. CT can be recommended as the first examination in seriously ill patients where abscesses and other causes of the symptoms than diverticulitis must first be rule out. Laparoscopy is probably the most accurate method in diagnosing diverticulitis. (orig.).

  12. Preoperative locoregional staging of rectal carcinoma: comparison of MR, TRUS and Multislice CT. Personal experience.

    Science.gov (United States)

    Panzironi, Giuseppe; De Vargas Macciucca, Marina; Manganaro, Lucia; Ballesio, Laura; Ricci, Francesca; Casale, Alessandra; Campagnano, Deborah

    2004-04-01

    The aim of this study was to measure the sensitivity and clinical indications of Magnetic Resonance (MR) as compared to Transrectal Ultrasonography (TRUS) and spiral Computed Tomography (CT) in the preoperative staging and evaluation of rectal carcinoma. Twenty patients with histologically proven rectal carcinoma were examined with phased-array coil MRI. We used T1 and T2, spin-echo, turbo-spin-echo, flash2D sequences with and without fat suppression; FOV 180-280; 4-6 mm slice thickness; i.v. Gadolinium. The MR images were compared with TRUS, spiral CT and with the final histological diagnosis. MR showed a 92.3% sensitivity for rectal wall infiltration vs. 100% of TRUS and 75% of CT. The sensitivity for lymph node metastases was 76.4% vs. 72.2% for TRUS and 88% for CT. Locoregional staging of rectal cancer by MRI shows a high sensitivity and is also feasible in stenosing or proximal rectal lesions. TRUS, despite its limitations, is still the most sensitive method for the evaluation of wall infiltration. CT was less sensitive than the other two The sensitivity of MR and CT for lymph node metastases is comparable, but the former is more specific.

  13. [CT and MR virtual colonscopy: indications, limits and comparison with conventional colonscopy].

    Science.gov (United States)

    Bertini, L; Campagnano, S; Lanciotti, S; Fiorello, S; Fabiani, B; Graziani, M G; Gualdi, G F

    2006-01-01

    Virtual endoscopy is a new method for studying the colon; it consists in acquisition of CT and MR images and to elaborate them with a workstation, to create endoluminal vision as like as traditional colonscopy, permitting the complete exploration of colonic lumen, also with stenotic tumors. The analysis of the differences between CT and MR colography shows like these two techniques present both advantages and disadvantages, such as the impossibility to perform MR in patients with pace-maker or in claustrophobic patients and the impossibility to perform CT with iodated agents in patients with renal failure or with a story of adverse reactions. The increased use of these techniques is due to the high sensitivity of last-generation CT and MR machine, to the increased spatial resolution, to specific softwares for digital cleaning of colon, to the introduction of high-end workstations and to the possibility of computed assisted diagnosis (CAD). So, it is desiderable that the increasing spread of multidetector CT devices and the future technical innovations, should have the effect to increase culture and experience in various diagnostic centers about CT-colography, making possible the spreading of virtual endoscopy as a screening tool.

  14. Use of CT to reduce understaging in prostatic cancer: comparison with conventional staging techniques

    Energy Technology Data Exchange (ETDEWEB)

    Emory, T.H.; Reinke, D.B.; Hill, A.L.; Lange, P.H.

    1983-08-01

    Thirty prostatic cancer patients were evaluated for staging purposes with both CT (18-sec scan speed) and certain commonly used conventional diagnostic tests, namely: radionuclide bone scan with correlative plain films, the prostatic fraction of the serum acid phosphatase, excretory urogram, and chest radiograph. All patients included in the study had histopathologic proof of diagnosis. CT correctly identified extracapsular prostatic cancer spread locally or in pelvic lymph nodes in 14% of patients with completely negative conventional studies. Sensitivity of extracapsular tumor spread detection increased from 41% to 59% by adding CT to the conventional studies. CT confirmed the presence of tumor spread and localized it in 43% of patients with positive conventional studies. Conventional studies were positive when tumor spread was present in 32% of patients with negative CT. CT reduces understaging when conventional tests are negative, localizes and conforms tumor spread when conventional tests are positive, but cannot demonstrate tumor spread in some patients whose conventional tests are positive and who are subsequently shown to have tumor spread histopathologically.

  15. Measurement of total lung capacity : a comparison of spiral CT and spirometry

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Kyung Il; Park, Kyung Ju; Lee, Eh Hyung; Yune, Heun Young; Suh, Jung Ho [Ajou Univ. School of Medicine, Suwon (Korea, Republic of); Choe, Kyu Ok; Lim, Tae Hwan [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of); Chung, In Hyuk [Ulsan Univ. College of Medicine, Seoul (Korea, Republic of)

    1996-08-01

    To determine the potential of spiral CT as a functional imaging modality of the lung aside from its proven value in morphological depiction. Spiral CT scan was performed in ten normal female and nine normal male adults (mean age: 39, height: 163 cm, weight: 62 kg ) after single full breath-holding. Three dimensional lung images were reconstructed(minimal threshold value: -1,000HU, maximal threshold values: -150, 250, -350, -450 HU) to obtain total lung volume(TLV) on a histogram. Total lung volume measured by spiral CT was compared with TLV obtained by spirometry. Mean TLV measured by spirometry was 5.62L and TLV measured by CT at maximal threshold values of -150, -250, -350, and -450 HU was 5.53, 5.33, 5.15, and 4.98L, respectively. Mean absolute differences between the modalities of 0.17L(3%), 0.32L(5.6%), 0.48L(8.5%), 0.65L(11.5%) were statistically significant(p<0.001). Linear regression coefficients between the modalities were 0.99, 0.97, 095, and 0.94 and no statistically significant differences in accuracy of threshold levels in the estimation of lung volume(r=0.99, standard error=0.034L in all) were seen. TLV measured by spiral CT closely approximated that measured by spirometry. Spiral CT may be useful as a means of evaluating lung function.

  16. Quantitative Image Quality Comparison of Reduced- and Standard-Dose Dual-Energy Multiphase Chest, Abdomen, and Pelvis CT.

    Science.gov (United States)

    Buty, Mario; Xu, Ziyue; Wu, Aaron; Gao, Mingchen; Nelson, Chelyse; Papadakis, Georgios Z; Teomete, Uygar; Celik, Haydar; Turkbey, Baris; Choyke, Peter; Mollura, Daniel J; Bagci, Ulas; Folio, Les R

    2017-06-01

    We present a new image quality assessment method for determining whether reducing radiation dose impairs the image quality of computed tomography (CT) in qualitative and quantitative clinical analyses tasks. In this Institutional Review Board-exempt study, we conducted a review of 50 patients (male, 22; female, 28) who underwent reduced-dose CT scanning on the first follow-up after standard-dose multiphase CT scanning. Scans were for surveillance of von Hippel-Lindau disease (N = 26) and renal cell carcinoma (N = 10). We investigated density, morphometric, and structural differences between scans both at tissue (fat, bone) and organ levels (liver, heart, spleen, lung). To quantify structural variations caused by image quality differences, we propose using the following metrics: dice similarity coefficient, structural similarity index, Hausdorff distance, gradient magnitude similarity deviation, and weighted spectral distance. Pearson correlation coefficient and Welch 2-sample t test were used for quantitative comparisons of organ morphometry and to compare density distribution of tissue, respectively. For qualitative evaluation, 2-sided Kendall Tau test was used to assess agreement among readers. Both qualitative and quantitative evaluations were designed to examine significance of image differences for clinical tasks. Qualitative judgment served as an overall assessment, whereas detailed quantifications on structural consistency, intensity homogeneity, and texture similarity revealed more accurate and global difference estimations. Qualitative and quantitative results indicated no significant image quality degradation. Our study concludes that low(er)-dose CT scans can be routinely used because of no significant loss in quantitative image information compared with standard-dose CT scans.

  17. Feasibility of simultaneous PET/MR of the carotid artery: first clinical experience and comparison to PET/CT

    Science.gov (United States)

    Ripa, Rasmus S; Knudsen, Andreas; Hag, Anne Mette F; Lebech, Anne-Mette; Loft, Annika; Keller, Sune H; Hansen, Adam E; von Benzon, Eric; Højgaard, Liselotte; Kjær, Andreas

    2013-01-01

    The study aimed at comparing PET/MR to PET/CT for imaging the carotid arteries in patients with known increased risk of atherosclerosis. Six HIV-positive men underwent sequential PET/MR and PET/CT of the carotid arteries after injection of 400 MBq of 18F-FDG. PET/MR was performed a median of 131 min after injection. Subsequently,PET/CT was performed. Regions of interest (ROI) were drawn slice by slice to include the carotid arteries and standardized uptake values (SUV) were calculated from both datasets independently. Quantitative comparison of 18F-FDG uptake revealed a high congruence between PET data acquired using the PET/MR system compared to the PET/CT system. The mean difference for SUVmean was -0.18 (p PET/MR system. The 95% limits of agreement were -0.55 to 0.20 for SUVmean and -0.93 to 0.65 for SUVmax. The image quality of the PET/MR allowed for delineation of the carotid vessel wall. The correlations between 18F-FDG uptake from ROI including both vessel wall and vessel lumen to ROI including only the wall were strong (r = 0.98 for SUVmean and r = 1.00 for SUVmax) indicating that the luminal 18F-FDG content had minimal influence on the values. The study shows for the first time that simultaneous PET/MR of the carotid arteries is feasible in patients with increased risk of atherosclerosis. Quantification of 18F-FDG uptake correlated well between PET/MR and PET/CT despite difference in method of PET attenuation correction, reconstruction algorithm, and detector technology. PMID:23900769

  18. Introduction of an effective method for the optimization of CT protocols using iterative reconstruction algorithms: comparison with patient data.

    Science.gov (United States)

    Kordolaimi, Sofia D; Saradeas, Ioannis; Ploussi, Agapi; Pantos, Ioannis; Argentos, Stylianos; Efstathopoulos, Efstathios P

    2014-10-01

    The purpose of this study is to introduce an efficient method for the optimization of iterative reconstruction CT protocols based on phantom image analysis and the comparison of obtained results with actual patient data. We considered chest, abdomen, and pelvis CT examinations before the installation of an iterative reconstruction algorithm (iDose4) to define the exposure parameters used in clinical routine with filtered back projection (FBP). The body area of a CT phantom was subsequently scanned with various tube voltages and tube currents-exposure time products, and acquired data were reconstructed with FBP and different levels of iDose4. The contrast-to-noise ratio (CNR) for FBP with the original exposure parameters was calculated to define the minimum acceptable CNR value for each tube voltage. Then, an optimum tube current-exposure time products for each tube voltage and level of iterative reconstruction was estimated. We also compared findings derived by the phantom with real patient data by assessing dosimetric and image quality indexes from a patient cohort scanned with exposure parameters gradually adjusted during 1 year of adoption of iDose4. By use of the proposed phantom method, dose reduction up to 75% was achievable, whereas for an intermediate level of iteration (level 4), the dose reduction ranged between 50% and 60%, depending on the tube voltage. For comparison, with the gradual adjustment of exposure settings, the corresponding dose reduction for the same level of iteration was about 35%. The proposed method provides rapid and efficient optimization of CT protocols and could be used as the first step in the optimization process.

  19. Comparison of Haller index values calculated with chest radiographs versus CT for pectus excavatum evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Khanna, Geetika; Jaju, Alok; Don, Steven; Hildebolt, Charles F. [Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Keys, Tim [Medical Physics Services Ltd., St Louis, MO (United States)

    2010-11-15

    Pectus excavatum is a common chest wall anomaly in children. Pre-operative imaging for pectus excavatum is performed with CT, which is used to calculate the Haller index to determine the severity of pectus excavatum. To determine the correlation between Haller index values calculated with two-view chest radiographs and those calculated with CT and to determine, with CT as the reference standard, the diagnostic performance of radiographic Haller index for identifying cases that meet imaging criteria for surgical correction of pectus excavatum. For the period 2001-2009, our radiology information system was searched to identify all children who had undergone CT for Haller index calculation. Children who had also undergone two-view chest radiography (CXR) within 6 months of the CT were included in this retrospective study. Two radiologists independently calculated CT Haller index and radiographic Haller index. Data distributions were tested for normality with the Shapiro-Wilk W test. The associations between CT Haller index and radiographic Haller index were determined with the Spearman coefficient of rank correlation. Differences between CT Haller index and radiographic Haller index were tested with the Wilcoxon signed rank test. Haller index values were dichotomized into positive (>3.2) and negative ({<=}3.2) cases. Using CT as the reference standard, the sensitivity, specificity, and accuracy of radiographic Haller index in identifying children who meet imaging criteria for surgery were calculated. CT and CXR for evaluation of pectus excavatum were available for 32 children (25 male; median age 14.5 years). With CT, the median Haller indices for observers 1 and 2 were 3.4 and 3.5 and with CXR 3.5 and 3.5. There were statistically significant correlations between the radiographic Haller index and CT Haller index estimated by the two observers [Spearman correlation coefficient (95% confidence interval) for observer 1 = 0.71 (0.48-0.85, P < 0.01) and for observer 2 = 0

  20. Alpha-Effect, Current and Kinetic Helicities for Magnetically Driven ...

    Indian Academy of Sciences (India)

    tribpo

    Astrophysikalisches Institut Potsdam, An der Sternwarte 16, D-14482 Potsdam, Germany. *e-mail: gbelvedere @alpha4. ct. astro. it. Key words. Sun—dynamo, helicity, turbulent convection. Extended abstract. Recent numerical simulations lead to the result that turbulence is much more mag- netically driven than believed.

  1. Submillisievert standard-pitch CT pulmonary angiography with ultra-low dose contrast media administration: A comparison to standard CT imaging.

    Science.gov (United States)

    Suntharalingam, Saravanabavaan; Mikat, Christian; Stenzel, Elena; Erfanian, Youssef; Wetter, Axel; Schlosser, Thomas; Forsting, Michael; Nassenstein, Kai

    2017-01-01

    To evaluate the image quality and radiation dose of submillisievert standard-pitch CT pulmonary angiography (CTPA) with ultra-low dose contrast media administration in comparison to standard CTPA. Hundred patients (56 females, 44 males, mean age 69.6±15.4 years; median BMI: 26.6, IQR: 5.9) with suspected pulmonary embolism were examined with two different protocols (n = 50 each, group A: 80 kVp, ref. mAs 115, 25 ml of contrast medium; group B: 100 kVp, ref. mAs 150, 60 ml of contrast medium) using a dual-source CT equipped with automated exposure control. Objective and subjective image qualities, radiation exposure as well as the frequency of pulmonary embolism were evaluated. There was no significant difference in subjective image quality scores between two groups regarding pulmonary arteries (p = 0.776), whereby the interobserver agreement was excellent (group A: k = 0.9; group B k = 1.0). Objective image analysis revealed that signal intensities (SI), signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the pulmonary arteries were equal or significantly higher in group B. There was no significant difference in the frequency of pulmonary embolism (p = 0.65). Using the low dose and low contrast media protocol resulted in a radiation dose reduction by 71.8% (2.4 vs. 0.7 mSv; pcontrast agent volume can obtain sufficient image quality to exclude or diagnose pulmonary emboli while reducing radiation dose by approximately 71%.

  2. FDG-PET/contrast-enhanced CT as a post-treatment tool in head and neck squamous cell carcinoma: comparison with FDG-PET/non-contrast-enhanced CT and contrast-enhanced CT

    Energy Technology Data Exchange (ETDEWEB)

    Suenaga, Yuko; Kitajima, Kazuhiro; Sugimura, Kazuro [Kobe University Graduate School of Medicine, Department of Radiology, Kobe (Japan); Ishihara, Takeaki; Sasaki, Ryohei [Kobe University Graduate, School of Medicine, Department of Radiology, Division of Radiation Oncology, Kobe (Japan); Otsuki, Naoki; Nibu, Ken-ichi [Kobe University Graduate, School of Medicine, Department of Otolaryngology-Head and Neck Surgery, Kobe (Japan); Minamikawa, Tsutomu [Kobe University Graduate School of Medicine, Department of Oral and Maxillofacial Surgery, Kobe (Japan); Kiyota, Naomi [Kobe University Hospital, Department of Medical Oncology and Hematology, Kobe (Japan)

    2016-04-15

    To evaluate the accuracy of PET/CT using {sup 18}F-fluorodeoxyglucose (FDG) with IV contrast for suspected recurrent head and neck squamous cell carcinoma (HNSCC). One hundred and seventy patients previously treated for HNSCC underwent PET/CT, consisting of non-contrast-enhanced and contrast-enhanced CT, to investigate suspected recurrence. Diagnostic performance of PET/contrast-enhanced CT (PET/ceCT), PET/non-contrast-enhanced CT (PET/ncCT) and contrast-enhanced CT (ceCT) for local or regional recurrence, distant metastasis, overall recurrence and second primary cancer was evaluated. The reference standard included histopathology, treatment change and imaging follow-up. The patient-based areas under the receiver operating characteristic curves (AUC) for ceCT, PET/ncCT and PET/ceCT were 0.82, 0.96 and 0.98 for local recurrence, 0.73, 0.86 and 0.86 for regional recurrence, 0.86, 0.91 and 0.92 for distant metastasis, 0.72, 0.86 and 0.87 for overall recurrence, and 0.86, 0.89 and 0.91 for a second primary cancer. Both PET/ceCT and PET/ncCT statistically showed larger AUC than ceCT for recurrence, and the difference between PET/ceCT and PET/ncCT for local recurrence reached a significant level (p = 0.039). The accuracy of PET/ceCT for diagnosing overall recurrence was high, irrespective of the time interval after the last treatment (83.3-94.1 %). FDG-PET/CT was a more accurate HNSCC restaging tool than ceCT. The added value of ceCT at FDG-PET/CT is minimal. (orig.)

  3. Comparison of radiation dose and image quality of triple-rule-out computed tomography angiography between conventional helical scanning and a strategy incorporating sequential scanning.

    Science.gov (United States)

    Manheimer, Eric D; Peters, M Robert; Wolff, Steven D; Qureshi, Mehreen A; Atluri, Prashanth; Pearson, Gregory D N; Einstein, Andrew J

    2011-04-01

    Triple-rule-out computed tomographic angiography (TRO CTA), performed to evaluate the coronary arteries, pulmonary arteries, and thoracic aorta, has been associated with high radiation exposure. The use of sequential scanning for coronary computed tomographic angiography reduces the radiation dose. The application of sequential scanning to TRO CTA is much less well defined. We analyzed the radiation dose and image quality from TRO CTA performed at a single outpatient center, comparing the scans from a period during which helical scanning with electrocardiographically controlled tube current modulation was used for all patients (n = 35) and after adoption of a strategy incorporating sequential scanning whenever appropriate (n = 35). Sequential scanning was able to be used for 86% of the cases. The sequential-if-appropriate strategy, compared to the helical-only strategy, was associated with a 61.6% dose decrease (mean dose-length product of 439 mGy × cm vs 1,144 mGy × cm and mean effective dose of 7.5 mSv vs 19.4 mSv, respectively, p strategy (326 mGy × cm vs 1,141 mGy × cm and 5.5 mSv vs 19.4 mSv, respectively, p strategies, a nonstatistically significant trend was seen toward better quality in the sequential protocol than in the helical protocol. In conclusion, approaching TRO CTA with a diagnostic strategy of sequential scanning, as appropriate, can offer a marked reduction in the radiation dose while maintaining the image quality. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. A comparison of sequential and spiral scanning techniques in brain CT.

    Science.gov (United States)

    Pace, Ivana; Zarb, Francis

    2015-01-01

    To evaluate and compare image quality and radiation dose of sequential computed tomography (CT) examinations of the brain and spiral CT examinations of the brain imaged on a GE HiSpeed NX/I Dual Slice 2CT scanner. A random sample of 40 patients referred for CT examination of the brain was selected and divided into 2 groups. Half of the patients were scanned using the sequential technique; the other half were scanned using the spiral technique. Radiation dose data—both the computed tomography dose index (CTDI) and the dose length product (DLP)—were recorded on a checklist at the end of each examination. Using the European Guidelines on Quality Criteria for Computed Tomography, 4 radiologists conducted a visual grading analysis and rated the level of visibility of 6 anatomical structures considered necessary to produce images of high quality. The mean CTDI(vol) and DLP values were statistically significantly higher (P vol): 22.06 mGy; DLP: 304.60 mGy • cm) than with the spiral scans (CTDI(vol): 14.94 mGy; DLP: 229.10 mGy • cm). The mean image quality rating scores for all criteria of the sequential scanning technique were statistically significantly higher (P <.05) in the visual grading analysis than those of the spiral scanning technique. In this local study, the sequential technique was preferred over the spiral technique for both overall image quality and differentiation between gray and white matter in brain CT scans. Other similar studies counter this finding. The radiation dose seen with the sequential CT scanning technique was significantly higher than that seen with the spiral CT scanning technique. However, image quality with the sequential technique was statistically significantly superior (P <.05).

  5. Quantification of interstitial fluid on whole body CT: comparison with whole body autopsy.

    Science.gov (United States)

    Lo Gullo, Roberto; Mishra, Shelly; Lira, Diego A; Padole, Atul; Otrakji, Alexi; Khawaja, Ranish Deedar Ali; Pourjabbar, Sarvenaz; Singh, Sarabjeet; Shepard, Jo-Anne O; Digumarthy, Subba R; Kalra, Mannudeep K; Stone, James R

    2015-12-01

    Interstitial fluid accumulation can occur in pleural, pericardial, and peritoneal spaces, and subcutaneous tissue planes. The purpose of the study was to assess if whole body CT examination in a postmortem setting could help determine the presence and severity of third space fluid accumulation in the body. Our study included 41 human cadavers (mean age 61 years, 25 males and 16 females) who had whole-body postmortem CT prior to autopsy. All bodies were maintained in the morgue in the time interval between death and autopsy. Two radiologists reviewed the whole-body CT examinations independently to grade third space fluid in the pleura, pericardium, peritoneum, and subcutaneous space using a 5-point grading system. Qualitative CT grading for third space fluid was correlated with the amount of fluid found on autopsy and the quantitative CT fluid volume, estimated using a dedicated software program (Volume, Syngo Explorer, Siemens Healthcare). Moderate and severe peripheral edema was seen in 16/41 and 7/41 cadavers respectively. It is not possible to quantify anasarca at autopsy. Correlation between imaging data for third space fluid and the quantity of fluid found during autopsy was 0.83 for pleural effusion, 0.4 for pericardial effusion and 0.9 for ascites. The degree of anasarca was significantly correlated with the severity of ascites (p < 0.0001) but not with pleural or pericardial effusion. There was strong correlation between volumetric estimation and qualitative grading for anasarca (p < 0.0001) and pleural effusion (p < 0.0001). Postmortem CT can help in accurate detection and quantification of third space fluid accumulation. The quantity of ascitic fluid on postmortem CT can predict the extent of anasarca.

  6. Transatlantic Comparison of CT Radiation Doses in the Era of Radiation Dose-Tracking Software.

    Science.gov (United States)

    Parakh, Anushri; Euler, Andre; Szucs-Farkas, Zsolt; Schindera, Sebastian T

    2017-12-01

    The purpose of this study is to compare diagnostic reference levels from a local European CT dose registry, using radiation-tracking software from a large patient sample, with preexisting European and North American diagnostic reference levels. Data (n = 43,761 CT scans obtained over the course of 2 years) for the European local CT dose registry were obtained from eight CT scanners at six institutions. Means, medians, and interquartile ranges of volumetric CT dose index (CTDI vol ), dose-length product (DLP), size-specific dose estimate, and effective dose values for CT examinations of the head, paranasal sinuses, thorax, pulmonary angiogram, abdomen-pelvis, renal-colic, thorax-abdomen-pelvis, and thoracoabdominal angiogram were obtained using radiation-tracking software. Metrics from this registry were compared with diagnostic reference levels from Canada and California (published in 2015), the American College of Radiology (ACR) dose index registry (2015), and national diagnostic reference levels from local CT dose registries in Switzerland (2010), the United Kingdom (2011), and Portugal (2015). Our local registry had a lower 75th percentile CTDI vol for all protocols than did the individual internationally sourced data. Compared with our study, the ACR dose index registry had higher 75th percentile CTDI vol values by 55% for head, 240% for thorax, 28% for abdomen-pelvis, 42% for thorax-abdomen-pelvis, 128% for pulmonary angiogram, 138% for renal-colic, and 58% for paranasal sinus studies. Our local registry had lower diagnostic reference level values than did existing European and North American diagnostic reference levels. Automated radiation-tracking software could be used to establish and update existing diagnostic reference levels because they are capable of analyzing large datasets meaningfully.

  7. Intrahepatic peripheral cholangiocarcinoma (IPCC): comparison between perfusion ultrasound and CT imaging.

    Science.gov (United States)

    D'Onofrio, M; Vecchiato, F; Cantisani, V; Barbi, E; Passamonti, M; Ricci, P; Malagò, R; Faccioli, N; Zamboni, G; Pozzi Mucelli, R

    2008-02-01

    This study was done to compare the perfusion patterns of intrahepatic peripheral cholangiocarcinoma (IPCC) on contrast-enhanced ultrasound (CEUS) and dynamic computed tomography (CT). We retrospectively reviewed 23 histologically proven cases of IPCC. All lesions were studied by CEUS with sulfur hexafluoride-filled microbubbles coated with a phospholipid capsule, and by dynamic CT. Contrast-enhancement patterns were evaluated in the arterial phase (CEUS 10-20 s after the injection; CT 25-30 s after the injection) and in the delayed phase (CEUS 120 s after the injection; CT>2-3 min after the injection). Lesions were single in 18/23 cases (78%), single with nearby satellite lesions in 1/23 (4%) cases and multifocal with distant secondary lesions in 4/23 (17%) cases. Lesion diameter was 2-5 cm in 7/23 cases (30%), 5-7 cm in 13/23 cases (57%) and >7 cm in 3/23 (13%) cases. On CEUS, lesions were hypervascular in 16/23 cases (70%). On delayed-phase CEUS, 22/23 lesions (96%) were markedly hypoechoic. CT showed that the lesions were hypovascular in the arterial phase in 15/23 cases (66%) and hypervascular in 7/23 (30%) cases; one lesion (1/23; 4%) was isovascular. On delayed-phase CT, lesions were hyperdense in 17/23 cases (74%), hypodense in 5/23 (22%) cases and isodense in 1/23 (43%) cases. Enhancement discrepancy between delayed-phase CEUS (hypoechogenicity) and CT (hyperdensity) is common semiological findings in the study of IPCC.

  8. Prospective evaluation of 68Ga-DOTA-NOC PET-CT in patients with recurrent medullary thyroid carcinoma: comparison with 18F-FDG PET-CT.

    Science.gov (United States)

    Naswa, Niraj; Sharma, Punit; Suman Kc, Sudhir; Lata, Sneh; Kumar, Rakesh; Malhotra, Arun; Bal, Chandrasekhar

    2012-07-01

    To prospectively evaluate the role of Ga-labelled [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]-1-NaI-octreotide (Ga-DOTA-NOC) PET-CT in patients with recurrent medullary thyroid carcinoma (MTC) and compare the same with F-fluorodeoxyglucose (F-FDG) PET-CT. Fifty-two consecutive patients with recurrent MTC based on raised serum calcitonin levels underwent Ga-DOTA-NOC PET-CT. In addition, 41 patients also underwent F-FDG PET-CT. PET-CT images were evaluated by two experienced nuclear medicine physicians both qualitatively and quantitatively (standardized uptake value). Histopathology (when available), correlation with conventional imaging modalities (ultrasonography/CT/MRI) and subsequent clinical/imaging follow-up were used as reference standard. Serum calcitonin levels were correlated with findings of PET-CT. Overall, Ga-DOTA-NOC PET-CT showed a sensitivity of 80.7% [95% confidence interval (CI) 67.4-90.3] and a positive predictive value of 100% (95% CI 91.5-100) for detecting recurrent MTC. When both were available (n=41), Ga-DOTA-NOC PET-CT proved superior to F-FDG PET-CT with a higher sensitivity (75.61 vs. 63.4%). However, the difference was statistically not significant (P=0.179). Ga-DOTA-NOC PET-CT was superior to F-FDG PET-CT for detecting recurrence in cervical lymph nodes (PNOC or F-FDG PET-CT. Both Ga-DOTA-NOC PET-CT and F-FDG PET-CT are able to localize disease recurrence in patients with MTC, and their role appears to be complementary for this purpose.

  9. Cine CT for Attenuation Correction in Cardiac PET/CT

    Science.gov (United States)

    Alessio, Adam M.; Kohlmyer, Steve; Branch, Kelley; Chen, Grace; Caldwell, James; Kinahan, Paul

    2008-01-01

    In dual-modality PET/CT systems, the CT scan provides the attenuation map for PET attenuation correction. The current clinical practice of obtaining a single helical CT scan provides only a snapshot of the respiratory cycle, whereas PET occurs over multiple respiratory cycles. Misalignment of the attenuation map and emission image because of respiratory motion causes errors in the attenuation correction factors and artifacts in the attenuation-corrected PET image. To rectify this problem, we evaluated the use of cine CT, which acquires multiple low-dose CT images during a respiratory cycle. We evaluated the average and the intensity-maximum image of cine CT for cardiac PET attenuation correction. Methods Cine CT data and cardiac PET data were acquired from a cardiac phantom and from multiple patient studies. The conventional helical CT, cine CT, and PET data of an axially translating phantom were evaluated with and without respiratory motion. For the patient studies, we acquired 2 cine CT studies for each PET acquisition in a rest–stress 13N-ammonia protocol. Three readers visually evaluated the alignment of 74 attenuation image sets versus the corresponding emission image and determined whether the alignment provided acceptable or unacceptable attenuation-corrected PET images. Results In the phantom study, the attenuation correction from helical CT caused a major artifactual defect in the lateral wall on the PET image. The attenuation correction from the average and from the intensity-maximum cine CT images reduced the defect by 20% and 60%, respectively. In the patient studies, 77% of the cases using the average of the cine CT images had acceptable alignment and 88% of the cases using the intensity maximum of the cine CT images had acceptable alignment. Conclusion Cine CT offers an alternative to helical CT for compensating for respiratory motion in the attenuation correction of cardiac PET studies. Phantom studies suggest that the average and the intensity

  10. Multi-institutional MicroCT image comparison of image-guided small animal irradiators

    Science.gov (United States)

    Johnstone, Chris D.; Lindsay, Patricia; E Graves, Edward; Wong, Eugene; Perez, Jessica R.; Poirier, Yannick; Ben-Bouchta, Youssef; Kanesalingam, Thilakshan; Chen, Haijian; E Rubinstein, Ashley; Sheng, Ke; Bazalova-Carter, Magdalena

    2017-07-01

    To recommend imaging protocols and establish tolerance levels for microCT image quality assurance (QA) performed on conformal image-guided small animal irradiators. A fully automated QA software SAPA (small animal phantom analyzer) for image analysis of the commercial Shelley micro-CT MCTP 610 phantom was developed, in which quantitative analyses of CT number linearity, signal-to-noise ratio (SNR), uniformity and noise, geometric accuracy, spatial resolution by means of modulation transfer function (MTF), and CT contrast were performed. Phantom microCT scans from eleven institutions acquired with four image-guided small animal irradiator units (including the commercial PXi X-RAD SmART and Xstrahl SARRP systems) with varying parameters used for routine small animal imaging were analyzed. Multi-institutional data sets were compared using SAPA, based on which tolerance levels for each QA test were established and imaging protocols for QA were recommended. By analyzing microCT data from 11 institutions, we established image QA tolerance levels for all image quality tests. CT number linearity set to R 2  >  0.990 was acceptable in microCT data acquired at all but three institutions. Acceptable SNR  >  36 and noise levels  1.5 lp mm-1 for MTF  =  0.2) was obtained at all but four institutions due to their large image voxel size used (>0.275 mm). Ten of the eleven institutions passed the set QA tolerance for geometric accuracy (2000 HU for 30 mgI ml-1). We recommend performing imaging QA with 70 kVp, 1.5 mA, 120 s imaging time, 0.20 mm voxel size, and a frame rate of 5 fps for the PXi X-RAD SmART. For the Xstrahl SARRP, we recommend using 60 kVp, 1.0 mA, 240 s imaging time, 0.20 mm voxel size, and 6 fps. These imaging protocols should result in high quality images that pass the set tolerance levels on all systems. Average SAPA computation time for complete QA analysis for a 0.20 mm voxel, 400 slice Shelley phantom microCT data set

  11. Renovascular CT: comparison between adaptive statistical iterative reconstruction and model-based iterative reconstruction.

    Science.gov (United States)

    Noda, Y; Goshima, S; Koyasu, H; Shigeyama, S; Miyoshi, T; Kawada, H; Kawai, N; Matsuo, M

    2017-10-01

    To compare contrast enhancement and image quality between renovascular computed tomography (CT) images with adaptive statistical iterative reconstruction (ASiR) and that with model-based iterative reconstruction (MBIR). This retrospective study was approved by the institutional review board and written informed consent was waived. Twenty-five consecutive patients who underwent renovascular CT were enrolled in this study. The same raw projection data were reconstructed using ASiR 40%, 100%, and MBIR. Background noise, CT attenuation, and signal-to-noise ratio (SNR) of the renal vessels and kidneys, and image quality were compared among the three reconstruction techniques. Mean background noise was significantly lower with MBIR at the first and second phases than those with ASiR 40% and 100% (pCT attenuation of the abdominal aorta, renal artery, and renal cortex obtained at the first phase and those of the renal vein and renal medulla at the second phase were comparable among the three techniques (p=0.051-1.00). Mean SNRs of the abdominal aorta, renal artery, renal cortex, renal vein, and renal medulla were significantly higher with MBIR than with ASiR 40% or 100% (both pReconstruction of renovascular CT images with MBIR significantly reduces background noise, leading to an improvement in SNR and image quality compared with that using ASiR. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  12. Comparison of CT and MRI brain tumor imaging using a canine glioma model.

    Science.gov (United States)

    Whelan, H T; Clanton, J A; Wilson, R E; Tulipan, N B

    1988-01-01

    A canine gliosarcoma model was used to study the effectiveness of magnetic resonance imaging (MRI) with gadolinium contrast enhancement in defining the histologic margins of brain tumors. The effectiveness of this technique was compared to conventional computed tomography (CT) using iodinated contrast enhancement. Cultured canine gliosarcoma cells were injected into the left hemisphere of adult mongrel dogs. The dogs developed brain tumors and progressive clinical signs. Serial MRI with and without gadolinium diethylene triamine penta-acetic acid was compared to serial CT with and without sodium iothalamate obtained on the same days. After the final scans, animals were sacrificed; the brains were removed and processed for routine histopathologic study. All tumors were visualized with contrast-enhanced MRI which proved most sensitive. Gadolinium di-ethylene triamine penta-acetic acid caused bright enhancement of tumors in a distribution that consistently corresponded to areas of pathologically proved tumor infiltration. Gross and microscopic autopsy findings correlated better with MRI than with CT which tended to produce poorer resolution and underrepresent the size of viable tumor. Gadolinium-enhanced MRI is more accurate than unenhanced MRI, unenhanced CT, or enhanced CT in defining the histologic margins of tumors.

  13. Renal colic: comparison of spiral CT, US and IVU in the detection of ureteral calculi.

    Science.gov (United States)

    Yilmaz, S; Sindel, T; Arslan, G; Ozkaynak, C; Karaali, K; Kabaalioğlu, A; Lüleci, E

    1998-01-01

    The aim of our study was to compare non-contrast spiral CT, US and intravenous urography (IVU) in the evaluation of patients with renal colic for the diagnosis of ureteral calculi. During a period of 17 months, 112 patients with renal colic were examined with spiral CT, US and IVU. Fifteen patients were lost to follow-up and excluded. The remaining 97 patients were defined to be either true positive or negative for ureterolithiasis based on the follow-up data. Sensitivity, specificity, positive and negative predictive value and accuracy of spiral CT, US and IVU were determined, and secondary signs of ureteral stones and other pathologies causing renal colic detected with these modalities were noted. Of 97 patients, 64 were confirmed to have ureteral calculi based on stone recovery or urological interventions. Thirty-three patients were proved not to have ureteral calculi based on failure to recover a stone and diagnoses unrelated to ureterolithiasis. Spiral CT was found to be the best modality for depicting ureteral stones with a sensitivity of 94 % and a specificity of 97 %. For US and IVU, these figures were 19, 97, 52, and 94 %, respectively. Spiral CT is superior to US and IVU in the demonstration of ureteral calculi in patients with renal colic, but because of its high cost, higher radiation dose and high workload, it should be reserved for cases where US and IVU do not show the cause of symptoms.

  14. Bone marrow trephine biopsy in Hodgkin's lymphoma. Comparison with PET-CT scan in 65 patients.

    Science.gov (United States)

    Lakhwani, Sunil; Cabello-García, Dolores; Allende-Riera, Ana; Cárdenas-Negro, Carlos; Raya, José María; Hernández-Garcia, Miguel T

    2018-02-09

    To compare bone marrow biopsy (BMB) and PET/CT in detecting bone marrow involvement in Hodgkin's lymphoma MATERIAL AND METHODS: Retrospective analysis of 65 patients with both tests in the initial staging or in relapse with special attention to the PET/CT uptake pattern. In 3 patients (4.6%), the BMB showed bone marrow involvement with the PET/CT being positive in them all: 2 with diffuse+multifocal pattern and one diffuse only. In 11 additional patients (total 14/65, 21%), bone marrow involvement was diagnosed by PET/CT because bone marrow uptake was above hepatic one. The pattern was focal only in 2 cases, multifocal in 5, diffuse in 3 and diffuse+multifocal in one. In these last 4 cases the BMB showed an unspecific myelopathy. PET/CT detects all cases with BMB affected and many that escape to biopsy, however when the uptake pattern is diffuse it could be by involvement or reactive hyperplasia and in those cases the BMB should be done. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

  15. Adenosine-stress dynamic myocardial perfusion imaging with second-generation dual-source CT: comparison with conventional catheter coronary angiography and SPECT nuclear myocardial perfusion imaging.

    Science.gov (United States)

    Wang, Yining; Qin, Ling; Shi, Ximin; Zeng, Yong; Jing, Hongli; Schoepf, U Joseph; Jin, Zhengyu

    2012-03-01

    The purpose of this article is to evaluate the feasibility of adenosine-stress dynamic myocardial perfusion imaging (MPI) with 128-MDCT dual-source CT for detecting myocardial ischemia in comparison with conventional catheter coronary angiography and nuclear MPI. Thirty patients (21 men and nine women; mean [± SD] age, 59.2 ± 7.6 years) prospectively underwent a combined stress CT perfusion and CT angiography (CTA) examination. Complete time-attenuation curves of the myocardium were acquired with prospectively ECG-triggered axial images at two alternating positions. Myocardial blood flow (MBF) was quantified according to dynamic CT perfusion, and MBF values of normal and abnormal segments were compared. Findings on CT perfusion were compared with those for stress and rest SPECT. Perfusion defects according to CT were correlated to flow-obstructing stenosis detected on CTA and catheter coronary angiography. On stress CT perfusion, 19 patients (63%) and 83 of 504 segments (16%) had perfusion abnormalities. There was a significant difference in MBF values between normal (142.9 ± 30.6 mL/100 mL/min) and hypoperfused (90.0 ± 22.8 mL/100 mL/min) segments (p stress CT perfusion detects myocardial perfusion defects in good correlation with nuclear MPI. CT perfusion combined with CTA improves the diagnostic accuracy for identifying flow-obstructing stenosis compared with CTA alone.

  16. Comparison of Three English-to-Dutch Machine Translations of SNOMED CT Procedures.

    Science.gov (United States)

    Cornet, Ronald; Hill, Carly; de Keizer, Nicolette

    2017-01-01

    Dutch interface terminologies are needed to use SNOMED CT in the Netherlands. Machine translation may support in their creation. The aim of our study is to compare different machine translations of procedures in SNOMED CT. Procedures were translated using Google Translate, Matecat, and Thot. Google Translate and Matecat are tools with large but general translation memories. The translation memory of Thot was trained and tuned with various configurations of a Dutch translation of parts of SNOMED CT, a medical dictionary and parts of the UMLS Metathesaurus. The configuration with the highest BLEU score, representing closeness to human translation, was selected. Similarity was determined between Thot translations and those by Google and Matecat. The validity of translations was assessed through random samples. Google and Matecat translated similarly in 85.4% of the cases and generally better than Thot. Whereas the quality of translations was considered acceptable, machine translations alone are yet insufficient.

  17. Chlamydia pneumoniae pneumonia and Mycoplasma pneumoniae pneumonia: comparison of clinical findings and CT findings.

    Science.gov (United States)

    Okada, Fumito; Ando, Yumiko; Wakisaka, Masaki; Matsumoto, Shunro; Mori, Hiromu

    2005-01-01

    The objective of this study was to identify the clinical and pulmonary CT findings associated with Chlamydia pneumoniae pneumonia and to compare them with those of Mycoplasma pneumoniae pneumonia. The clinical features and CT scans of 40 patients with C. pneumoniae pneumonia and 42 patients with M. pneumoniae pneumonia were retrospectively reviewed. There were no significant differences between the two etiologic agents with regard to clinical signs. Chest CT findings in patients with C. pneumoniae pneumonia consisted mainly of ground-glass attenuation (n = 38) and acinar patterns (n = 28). Acinar patterns and pleural effusions (n = 12) were observed significantly more frequently than in patients with M. pneumoniae pneumonia (P pneumoniae pneumonia patients (P pneumoniae pneumonia.

  18. MRI evaluation of complex renal cysts using the Bosniak classification: a comparison to CT.

    Science.gov (United States)

    Ferreira, Aila Menezes; Reis, Rodolfo Borges; Kajiwara, Plinio Prizon; Silva, Gyl Eanes Barros; Elias, Jorge; Muglia, Valdair Francisco

    2016-10-01

    The purpose of this study was to compare the ability of magnetic resonance imaging (MRI) and computed tomography (CT) to discriminate between benign and malignant cystic renal lesions utilizing the Bosniak classification. We retrospectively searched our Radiological Information System using renal/kidney cysts as entries. The search retrieved 2929 patients and 525 complex renal cysts. After exclusions, 42 complex cysts, from 37 patients, with CT and MRI, up to six months apart, were included. Surgery and pathology report and follow-up of at least 24 months were used as a standard of reference. The mean age of patients was 51.4 years, ranging from 11 to 82 years old. Twenty-nine lesions were classified as Bosniak I, II or II-F by CT and/or MRI and 13 as Bosniak III or IV, by one of the methods. The interobserver agreement for Bosniak classification for CT was 0.87 and 0.93 for MRI. Fifteen lesions had higher Bosniak categories on MRI, included six with change in management. Only two lesions had a higher category on CT, one with change in management. The frequency of malignancy for Bosniak III was 50 % (2/4) for CT and 20% for MRI (1/5), as Bosniak upgrades by MRI resulted in surgery for benign lesions. Both methods had 100 % frequency of malignancy for category 4. MRI led to category migration and management change of complex renal cysts in a significant proportion of cases, likely due to its superior soft tissue and contrast resolution. The impact of MRI on detection and outcomes of malignant complex renal cysts still requires further investigation.

  19. Colorectal cancer staging: comparison of whole-body PET/CT and PET/MR.

    Science.gov (United States)

    Catalano, Onofrio A; Coutinho, Artur M; Sahani, Dushyant V; Vangel, Mark G; Gee, Michael S; Hahn, Peter F; Witzel, Thomas; Soricelli, Andrea; Salvatore, Marco; Catana, Ciprian; Mahmood, Umar; Rosen, Bruce R; Gervais, Debra

    2017-04-01

    Correct staging is imperative for colorectal cancer (CRC) since it influences both prognosis and management. Several imaging methods are used for this purpose, with variable performance. Positron emission tomography-magnetic resonance (PET/MR) is an innovative imaging technique recently employed for clinical application. The present study was undertaken to compare the staging accuracy of whole-body positron emission tomography-computed tomography (PET/CT) with whole-body PET/MR in patients with both newly diagnosed and treated colorectal cancer. Twenty-six patients, who underwent same day whole-body (WB) PET/CT and WB-PET/MR, were evaluated. PET/CT and PET/MR studies were interpreted by consensus by a radiologist and a nuclear medicine physician. Correlations with prior imaging and follow-up studies were used as the reference standard. Correct staging was compared between methods using McNemar's Chi square test. The two methods were in agreement and correct for 18/26 (69%) patients, and in agreement and incorrect for one patient (3.8%). PET/MR and PET/CT stages for the remaining 7/26 patients (27%) were discordant, with PET/MR staging being correct in all seven cases. PET/MR significantly outperformed PET/CT overall for accurate staging (P = 0.02). PET/MR outperformed PET/CT in CRC staging. PET/MR might allow accurate local and distant staging of CRC patients during both at the time of diagnosis and during follow-up.

  20. PET/MR in the Assessment of Pediatric Histiocytoses: A Comparison to PET/CT.

    Science.gov (United States)

    Sher, Andrew C; Orth, Robert; McClain, Kenneth; Allen, Carl; Hayatghaibi, Shireen; Seghers, Victor

    2017-08-01

    The aim of this study was to analyze the feasibility and diagnostic performance of F-FDG PET/MR compared with F-FDG PET/CT in a cohort of pediatric histiocytosis patients with regard to image quality, lesion detection, and FDG quantification. Children with a diagnosis of Langerhans cell histiocytosis or Rosai-Dorfman disease were prospectively recruited. Seventeen PET/CT and PET/MR examinations were performed on 9 patients (mean age, 6.2 years) following a single-injection dual-imaging protocol. The indication was Langerhans cell histiocytosis in 10 examinations and Rosai-Dorfman disease in 7 examinations. The anonymized data were evaluated for image quality and lesion detection. SUV quantification of each lesion was compared between modalities. All PET/MR examinations had good or excellent image quality and were deemed clinically acceptable. There was substantial agreement of PET image quality among readers of PET/MR images. Per patient, PET/MR and PET/CT had complete concordance in identifying active disease. PET/MRI correctly classified 74 (96%) of 77 foci of disease identified on PET/CT. The per-lesion maximum SUVs were strongly correlated between modalities with a Spearman correlation coefficient of 0.73 (P PET/MR is clinically feasible in pediatric patients with a histiocytic disease. PET/MR demonstrates comparable image quality and lesion detection to PET/CT while maintaining strongly correlated quantitative performance. Given the significant radiation dose savings, PET/MR represents an appealing alternative to PET/CT in the care of children with histiocytic disorders.

  1. Comparison of intracranial computed tomographic (CT) findings in pediatric abusive and accidental head trauma

    Energy Technology Data Exchange (ETDEWEB)

    Hymel, K.P. [University of Colorado Health Sciences Center, 1056 East 19th Avenue, Denver, CO 80218 (United States); Rumack, C.M. [University of Colorado Health Sciences Center, 1056 East 19th Avenue, Denver, CO 80218 (United States); Hay, T.C. [University of Colorado Health Sciences Center, 1056 East 19th Avenue, Denver, CO 80218 (United States); Strain, J.D. [University of Colorado Health Sciences Center, 1056 East 19th Avenue, Denver, CO 80218 (United States); Jenny, C. [University of Colorado Health Sciences Center, 1056 East 19th Avenue, Denver, CO 80218 (United States)

    1997-09-01

    Background. Child abuse specialists rely heavily on diagnostic neuroimaging. Objectives. Study objectives were: (1) to compare the frequencies of six specific intracranial CT abnormalities in accidental and non-accidental pediatric head trauma, and (2) to assess interobserver agreement regarding these CT findings. Materials and methods. Three pediatric radiologists blindly and independently reviewed cranial CT scans of pediatric patients who sustained closed head trauma between 1991 and 1994. All patients were less than 4 years of age. Study cases included thirty-nine (50 %) with non-accidental head trauma and thirty-nine (50 %) with accidental head trauma. Each scan was evaluated for the presence or absence of the following six intracranial findings: (1) interhemispheric falx hemorrhage, (2) subdural hemorrhage, (3) large (non-acute) extra-axial fluid, (4) basal ganglia edema, (5) posterior fossa hemorrhage, and (6) frontal-parietal shearing tear(s). Interobserver agreement was calculated as the percentage of total cases in which all reviewers agreed a specific CT finding was present or absent. Diagnosis required independent agreement by all three pediatric radiologists. The frequencies of these six intracranial CT abnormalities were compared between the two study groups by Chi-square analysis and Fisher`s exact test. Results. Interobserver agreement between radiologists was greater than 80 % for all lesions evaluated, with the exception of frontal-parietal shearing tear(s). Interhemispheric falx hemorrhage, subdural hemorrhage, large (non-acute) extra-axial fluid, and basal ganglia edema were discovered significantly more frequently in non-accidental trauma (P {<=}.05). Conclusion. Although not specific for child abuse, discovery of these intracranial CT abnormalities in young patients should prompt careful evaluation of family and injury circumstances for indicators of non-accidental trauma. (orig.). With 6 figs., 2 tabs.

  2. Tuberculous adenitis: comparison of CT and MRI findings with histopathological features

    Energy Technology Data Exchange (ETDEWEB)

    Backer, A.I. de [General Hospital Sint-Lucas, Department of Radiology, Ghent (Belgium); Mortele, K.J. [Harvard Medical School, Department of Radiology, Division of Abdominal Imaging and Intervention, Brigham and Women' s Hospital, Boston, MA (United States); Heuvel, E. van den [University Hospital of Antwerp, Department of Pathology, Edegem (Belgium); Vanschoubroeck, I.J. [Ziekenhuisnetwerk Antwerpen, Stuivenberg, Department of Internal Medicine, Antwerp (Belgium); Kockx, M.M. [Ziekenhuisnetwerk Antwerpen, Stuivenberg, Department of Pathology, Antwerp (Belgium); Vyvere, M. van de [Ziekenhuisnetwerk Antwerpen, Stuivenberg, Department of Microbiology, Antwerp (Belgium)

    2007-04-15

    Our aim was to investigate the relationship between the various histopathological features and the CT and MRI findings in routinely submitted histopathological specimens for the diagnosis of tuberculous lymphadenopathy. Twelve formalin-fixed, paraffin-embedded tissue blocks from ten patients who were clinically suspected of having tuberculous lymphadenopathy were evaluated. We assessed the presence of histopathological features including granuloma formation, caseous necrosis, and presence of Langhans-type giant cells, calcifications, fibrosis or normal lymphoid tissue. We performed polymerase chain reaction (PCR)-based assay for mycobacterial DNA and Ziehl-Neelsen staining for acid-fast bacilli (AFB). Findings were compared with those of CT and MRI, including signal intensities on unenhanced MR images, lymph node homogeneity, attenuation values on contrast-enhanced CT and enhancement patterns on MRI. Based on CT and MRI findings, four lymph node types could be defined: (1) homogeneous nodes, visible on both pre- and post-contrast images and corresponding histopathologically to granulation tissue without or with minimal caseation necrosis (n = 2); (2) heterogeneous nodes, showing heterogeneous enhancement patterns with central non-enhancing areas and corresponding to minor or moderate intranodal caseation/liquefaction necrosis (n = 3); (3) nodes showing peripheral rim enhancement and corresponding to moderate or extensive intranodal caseation/liquefaction necrosis (n = 5); (4) heterogeneous nodes showing intranodal hyperdensities on CT and hypointense areas on T1- and T2-weighted images and corresponding to fibrosis and calcifications (n = 2). On CT and MRI, the findings reflect different stages of the tuberculous process. Imaging findings depend on the presence and the degree of granuloma formation, caseation/liquefaction necrosis, fibrosis and calcifications. (orig.)

  3. Quantitative Rapid Assessment of Leukoaraiosis in CT : Comparison to Gold Standard MRI.

    Science.gov (United States)

    Hanning, Uta; Sporns, Peter Bernhard; Schmidt, Rene; Niederstadt, Thomas; Minnerup, Jens; Bier, Georg; Knecht, Stefan; Kemmling, André

    2017-10-20

    The severity of white matter lesions (WML) is a risk factor of hemorrhage and predictor of clinical outcome after ischemic stroke; however, in contrast to magnetic resonance imaging (MRI) reliable quantification for this surrogate marker is limited for computed tomography (CT), the leading stroke imaging technique. We aimed to present and evaluate a CT-based automated rater-independent method for quantification of microangiopathic white matter changes. Patients with suspected minor stroke (National Institutes of Health Stroke scale, NIHSS < 4) were screened for the analysis of non-contrast computerized tomography (NCCT) at admission and compared to follow-up MRI. The MRI-based WML volume and visual Fazekas scores were assessed as the gold standard reference. We employed a recently published probabilistic brain segmentation algorithm for CT images to determine the tissue-specific density of WM space. All voxel-wise densities were quantified in WM space and weighted according to partial probabilistic WM content. The resulting mean weighted density of WM space in NCCT, the surrogate of WML, was correlated with reference to MRI-based WML parameters. The process of CT-based tissue-specific segmentation was reliable in 79 cases with varying severity of microangiopathy. Voxel-wise weighted density within WM spaces showed a noticeable correlation (r = -0.65) with MRI-based WML volume. Particularly in patients with moderate or severe lesion load according to the visual Fazekas score the algorithm provided reliable prediction of MRI-based WML volume. Automated observer-independent quantification of voxel-wise WM density in CT significantly correlates with microangiopathic WM disease in gold standard MRI. This rapid surrogate of white matter lesion load in CT may support objective WML assessment and therapeutic decision-making during acute stroke triage.

  4. FDG PET/CT in cancer: comparison of actual use with literature-based recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Henrik; Johansen, Allan; Hoeilund-Carlsen, Poul Flemming [Odense University Hospital, Department of Nuclear Medicine, Odense C (Denmark); Holdgaard, Paw Christian [Vejle Hospital, Department of Nuclear Medicine, Vejle (Denmark); Madsen, Poul Henning [Vejle Hospital, Department of Medicine, Vejle (Denmark); Knudsen, Lene Meldgaard [Odense University Hospital, Department of Haematological, Odense (Denmark); Gad, Dorte; Gravergaard, Anders Eggert [Odense University Hospital, Department of Plastic Surgery, Odense (Denmark); Rohde, Max; Godballe, Christian [Odense University Hospital, Department of ORL Head and Neck Surgery, Odense (Denmark); Engelmann, Bodil Elisabeth [Naestved Sygehus, Department of Clinical Physiology and Nuclear Medicine, Naestved (Denmark); Bech, Karsten [Aabenraa Sygehus, Organ Centre, Aabenraa (Denmark); Teilmann-Joergensen, Dorte [Aabenraa Sygehus, Department of Gynaecoligcal and Obstetrics, Aabenraa (Denmark); Mogensen, Ole [Odense University Hospital, Department of Gynaecoligcal and Obstetrics, Odense (Denmark); Karstoft, Jens [Odense University Hospital, Department of Radiology, Odense (Denmark); Johansen, Joergen [Odense University Hospital, Department of Oncology, Odense (Denmark); Christensen, Janne Buck [Odense University Hospital, Department of Quality and Research/HTA, Odense (Denmark); Collaboration: on behalf of the PET/CT Task Force of the Region of Southern Denmark

    2016-04-15

    The Region of Southern Denmark (RSD), covering 1.2 of Denmark's 5.6 million inhabitants, established a task force to (1) retrieve literature evidence for the clinical use of positron emission tomography (PET)/CT and provide consequent recommendations and further to (2) compare the actual use of PET/CT in the RSD with these recommendations. This article summarizes the results. A Work Group appointed a professional Subgroup which made Clinician Groups conduct literature reviews on six selected cancers responsible for 5,768 (62.6 %) of 9,213 PET/CT scans in the RSD in 2012. Rapid Evidence Assessment was applied, using the methodology of systematic reviews with predefined limitations to search PubMed, Embase and the Cochrane Library for articles published in English/Danish/Swedish/Norwegian since 2002. PICO questions were defined, data recorded and quality appraised and rated with regard to strength and evidence level. Consequent recommendations for applications of PET/CT were established. The actual use of PET/CT was compared with these, where grades A and B indicated ''established'' and ''useful'' and grades C and D ''potentially useful'' and ''non-recommendable'' indications, respectively. Of 11,729 citations, 1,729 were considered for review, and 204 were included. The evidence suggested usefulness of PET/CT in lung, lymphoma, melanoma, head and neck, and colorectal cancers, whereas evidence was sparse in gynaecological cancers. The agreement between actual use of PET/CT and literature-based recommendations was high in the first five mentioned cancers in that 96.2 % of scans were made for grade A or B indications versus only 22.2 % in gynaecological cancers. Evidence-based usefulness was reported in five of six selected cancers; evidence was sparse in the sixth, gynaecological cancers. Actual use of PET/CT agreed well with recommendations. (orig.)

  5. Value of postmortem computed tomography in comparison to autopsy; Prospektive Untersuchung zur Wertigkeit der postmortalen Computertomographie im Vergleich zur Autopsie

    Energy Technology Data Exchange (ETDEWEB)

    Paperno, S.; Krug, B.; Lackner, L. [Klinik und Poliklinik fuer Radiologische Diagnostik, Univ. zu Koeln (Germany); Riepert, T.; Rothschild, M.A.; Schultes, A.; Staak, M. [Inst. fuer Rechtsmedizin des Klinikums der Univ. zu Koeln (Germany)

    2005-01-01

    Purpose: to assess the diagnostic value of postmortem computed tomography (CT) in comparison to autopsy. Materials and methods: twenty-seven cadavers were examined by sequential cranial CT and helical CT through the neck, thorax and abdomen and subsequently underwent an autopsy with histomorphologic examination of the pathologic specimens. The findings of CT, autopsy and histology were registered and compared by three radiologists and one specialist for forensic medicine, using a data entry form. Results: in 19 of 27 cases, the findings explaining the cause of death were concordant for CT and autopsy. Intracranial, intraspinal and intracardiac gas accumulations (n = 12) were registered by CT alone. The detection of skull fractures was equal for both methods (n = 3). CT showed diagnostic problems in the assessment of pneumonic infiltrations (n = 16) and pulmonary edema (n = 21). Conclusion: CT is a useful and complementary method to autopsy. (orig.)

  6. Feasibility and preliminary results of SPECT/CT arthrography of the wrist in comparison with MR arthrography in patients with suspected ulnocarpal impaction

    Energy Technology Data Exchange (ETDEWEB)

    Strobel, Klaus [Lucerne Cantonal Hospital, Department of Nuclear Medicine and Radiology, Lucerne (Switzerland); Kantonsspital Luzern, Roentgeninstitut/Nuklearmedizin, Luzern (Switzerland); Steurer-Dober, Isabelle; Huellner, Martin W.; Sol Perez Lago, Maria del; Veit-Haibach, Patrick; Tornquist, Katharina [Lucerne Cantonal Hospital, Department of Nuclear Medicine and Radiology, Lucerne (Switzerland); Silva, Angela J. da [Advanced Molecular Imaging, Philips Healthcare, San Jose, CA (United States); Bodmer, Elvira; Wartburg, Urs von; Hug, Urs [Lucerne Cantonal Hospital, Division of Hand and Plastic Surgery, Lucerne (Switzerland)

    2014-03-15

    To evaluate the feasibility and performance of SPECT/CT arthrography of the wrist in comparison with MR arthrography in patients with suspected ulnocarpal impaction. This prospective study included 28 wrists of 27 patients evaluated with SPECT/CT arthrography and MR arthrography. Iodine contrast medium and gadolinium were injected into the distal radioulnar and midcarpal joints. Late-phase SPECT/CT was performed 3.5 h after intravenous injection of approximately 650 MBq {sup 99m}Tc-DPD. MR and SPECT/CT images were separately reviewed in relation to bone marrow oedema, radionuclide uptake, and tears in the scapholunate (SL) and lunotriquetral (LT) ligaments and triangular fibrocartilage complex (TFCC), and an overall diagnosis of ulnar impaction. MR, CT and SPECT/CT imaging findings were compared with each other, with the surgical findings in 12 patients and with clinical follow-up. The quality of MR arthrography and SPECT/CT arthrography images was fully diagnostic in 23 of 28 wrists (82 %) and 25 of 28 wrists (89 %), respectively. SPECT/CT arthrography was not diagnostic for ligament lesions due to insufficient intraarticular contrast in one wrist. MR and SPECT/CT images showed concordant findings regarding TFCC lesions in 22 of 27 wrists (81 %), SL ligament in 22 of 27 wrists (81 %) and LT ligament in 23 of 27 wrists (85 %). Bone marrow oedema on MR images and scintigraphic uptake were concordant in 21 of 28 wrists (75 %). MR images showed partial TFCC defects in four patients with normal SPECT/CT images. MR images showed bone marrow oedema in 4 of 28 wrists (14 %) without scintigraphic uptake, and scintigraphic uptake was present without MR bone marrow oedema in three wrists (11 %). Regarding diagnosis of ulnar impaction the concordance rate between CT and SPECT/CT was 100 % and reached 96 % (27 of 28) between MR and SPECT/CT arthrography. The sensitivity and specificity of MR, CT and SPECT/CT arthrography were 93 %, 100 % and 100 %, and 93 %, 93 % and 93

  7. Evaluation of the degree of pancreatic fatty infiltration by area-based assessment of CT images: comparison with histopathology-based and CT attenuation index-based assessments.

    Science.gov (United States)

    Hori, Mika; Onaya, Hiroaki; Hiraoka, Nobuyoshi; Yamaji, Taiki; Kobayashi, Hideaki; Takahashi, Mami; Mutoh, Michihiro; Shimada, Kazuaki; Nakagama, Hitoshi

    2016-10-01

    The purpose of this study was to evaluate the degree of fatty infiltration (FI) of the pancreas using area-based assessment on computed tomography (CT) (CT area-based assessment) in its correlation and agreement/concordance with histopathology-based assessment. Furthermore, we examined whether CT area-based assessment was better than CT attenuation index-based assessment. We retrospectively evaluated the degree of FI of the pancreas in 37 pancreatic cancer patients who had undergone preoperative CT and pancreaticoduodenectomy. The degree of FI of the pancreas was examined by histopathology-based assessment using surgical resection samples, and CT area-based and CT attenuation index-based assessments. Mean values of pancreatic FI measured by area-based assessment on unenhanced CT and by histopathology-based assessments were 14.4 ± 23.2 % (range 0-77.7 %) and 16.2 ± 17.4 % (range 0.2-60.2 %), respectively. Area-based assessment on unenhanced CT showed higher correlation and concordance with histopathology-based assessment, demonstrating a Spearman correlation coefficient of 0.78 (P assessment, the corresponding values were -0.66 (P assessment is suggested to be better than CT attenuation index-based assessment.

  8. [Evaluation of non-enhanced spiral CT in the assessment of renal colic: prospective series of 81 patients].

    Science.gov (United States)

    Anfossi, Eric; Eghazarian, Christophe; Portier, François; Prost, Jérôme; Ragni, Evelyne; Daou, Nabil; Rossi, Dominique

    2003-02-01

    For many years, intravenous urography has been the first-line investigation for renal colic. Since the middle of the 1990s, non-enhanced spiral CT has become a more efficient, less invasive and less expensive alternative to IVU. The aim of this study was to compare non-enhanced spiral CT and IVU in the assessment of renal colic and to evaluate the possibility of exclusive CT assessment in this disease. Prospective study including 81 patients all undergoing urgent non-enhanced spiral CT, while the first 30 patients were investigated by non-enhanced spiral CT and IVU. Comparison of IVU versus CT: better sensitivity of CT for the diagnosis of renal colic (96% vs 92%) and for the detection of stones (95% vs 59%). CT diagnosis: A definitive diagnosis of renal colic was established in 72/81 patients: stone visualized in 64 cases and post colic syndrome in 8 cases, while the other 9 patients presented a non-urological abdominal disease. Comparison of our series with results reported in the literature confirms the superiority of CT over IVU with better visualization of the stone at a lower cost, with a shorter examination time, without injection and allowing the detection of non-urological disease. Analysis of CT signs emphasizes the importance of secondary signs for the diagnosis of renal colic (dilatation, perirenal or ureteric oedema, rim sign). Delayed excretion demonstrated by IVU and not directly evaluable by non-enhanced CT is no longer an argument in favour of IVU as first-line examination for the assessment of renal colic. The superiority of CT for the diagnosis of renal colic has now been demonstrated. Renal colic can now be assessed exclusively by first-line non-enhanced helical CT. IVU or contrast-enhanced CT may be indicated in rare cases when there is a doubt about the diagnosis on non-enhanced CT.

  9. Comparison of 18F-FDG PET/CT for Systemic Staging of Newly Diagnosed Invasive Lobular Carcinoma Versus Invasive Ductal Carcinoma.

    Science.gov (United States)

    Hogan, Molly P; Goldman, Debra A; Dashevsky, Brittany; Riedl, Christopher C; Gönen, Mithat; Osborne, Joseph R; Jochelson, Maxine; Hudis, Clifford; Morrow, Monica; Ulaner, Gary A

    2015-11-01

    Although guidelines such as those of the National Comprehensive Cancer Network consider (18)F-FDG PET/CT for systemic staging of newly diagnosed stage III breast cancer patients, factors in addition to stage may influence the utility of PET/CT. Because invasive lobular carcinoma (ILC) is less conspicuous than invasive ductal carcinoma (IDC) on (18)F-FDG PET, we hypothesized that tumor histology may be one such factor. We evaluated PET/CT systemic staging of patients newly diagnosed with ILC compared with IDC. In this Institutional Review Board-approved retrospective study, our Hospital Information System was screened for ILC patients who underwent PET/CT in 2006-2013 before systemic or radiation therapy. Initial stage was determined from examination, mammography, ultrasound, MR, or surgery. PET/CT was performed to identify unsuspected distant metastases. A sequential cohort of stage III IDC patients was evaluated for comparison. Upstaging rates were compared using the Pearson χ(2) test. The study criteria were fulfilled by 146 ILC patients. PET/CT revealed unsuspected distant metastases in 12 (8%): 0 of 8 with initial stage I, 2 of 50 (4%) stage II, and 10 of 88 (11%) stage III. Upstaging to IV by PET/CT was confirmed by biopsy in all cases. Three of 12 upstaged patients were upstaged only by the CT component of the PET/CT, as the metastases were not (18)F-FDG-avid. In the comparison stage III IDC cohort, 22% (20/89) of patients were upstaged to IV by PET/CT. All 20 demonstrated (18)F-FDG-avid metastases. The relative risk of PET/CT revealing unsuspected distant metastases in stage III IDC patients was 1.98 times (95% confidence interval, 0.98-3.98) that of stage III ILC patients (P = 0.049). For (18)F-FDG-avid metastases, the relative risk of PET/CT revealing unsuspected (18)F-FDG-avid distant metastases in stage III IDC patients was 2.82 times (95% confidence interval, 1.26-6.34) that of stage III ILC patients (P = 0.007). (18)F-FDG PET/CT was more likely to

  10. Comparison of PET/CT and whole-mount histopathology sections of the human prostate: a new strategy for voxel-wise evaluation.

    Science.gov (United States)

    Schiller, F; Fechter, T; Zamboglou, C; Chirindel, A; Salman, N; Jilg, C A; Drendel, V; Werner, M; Meyer, P T; Grosu, A-L; Mix, M

    2017-08-17

    Implementation of PET/CT in diagnosis of primary prostate cancer (PCa) requires a profound knowledge about the tracer, preferably from a quantitative evaluation. Direct visual comparison of PET/CT slices to whole prostate sections is hampered by considerable uncertainties from imperfect coregistration and fundamentally different image modalities. In the current study, we present a novel method for advanced voxel-wise comparison of histopathology from excised prostates to pre-surgical PET. Resected prostates from eight patients who underwent PSMA-PET/CT were scanned (ex vivo CT) and thoroughly pathologically prepared. In vivo and ex vivo CT including histopathology were coregistered with three different methods (manual, semi-/automatic). Spatial overlap after CT-based registration was evaluated with dice similarity (DSC). Furthermore, we constructed 3D cancer distribution models from histopathologic information in various slices. Subsequent smoothing reflected the intrinsically limited spatial resolution of PSMA-PET. The resulting histoPET models were used for quantitative analysis of spatial histopathology-PET pattern agreement focusing on p values and coefficients of determination (R 2 ). We examined additional rigid mutual information (MI) coregistration directly based on PSMA-PET and histoPET. Mean DSC for the three different methods (ManReg, ScalFactReg, and DefReg) were 0.79 ± 0.06, 0.82 ± 0.04, and 0.90 ± 0.02, respectively, while quantification of PET-histopathology pattern agreement after CT-based registration revealed R 2 45.7, 43.2, and 41.3% on average with p histopathological preparation allowed sophisticated quantitative analyses showing highly significant correlations between histopathology and (PSMA-)PET. We recommend manual CT-based coregistration followed by a PET-based MI algorithm to overcome limitations of purely CT-based coregistrations for meaningful voxel-wise comparisons between PET and histopathology.

  11. SU-D-207B-03: A PET-CT Radiomics Comparison to Predict Distant Metastasis in Lung Adenocarcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Coroller, T; Yip, S; Lee, S; Mak, R; Aerts, H [Dana Farber Cancer Institute, Brigham and Women’s Hospital, Havard Medical School, Boston, MA (United States); Kim, J [Brigham and Women’s Hospital, Children’s hospital, Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: Early prediction of distant metastasis may provide crucial information for adaptive therapy, subsequently improving patient survival. Radiomic features that extracted from PET and CT images have been used for assessing tumor phenotype and predicting clinical outcomes. This study investigates the values of radiomic features in predicting distant metastasis (DM) in non-small cell lung cancer (NSCLC). Methods: A total of 108 patients with stage II–III lung adenocarcinoma were included in this retrospective study. Twenty radiomic features were selected (10 from CT and 10 from PET). Conventional features (metabolic tumor volume, SUV, volume and diameter) were included for comparison. Concordance index (CI) was used to evaluate features prognostic value. Noether test was used to compute p-value to consider CI significance from random (CI = 0.5) and were adjusted for multiple testing using false rate discovery (FDR). Results: A total of 70 patients had DM (64.8%) with a median time to event of 8.8 months. The median delivered dose was 60 Gy (range 33–68 Gy). None of the conventional features from PET (CI ranged from 0.51 to 0.56) or CT (CI ranged from 0.57 to 0.58) were significant from random. Five radiomics features were significantly prognostic from random for DM (p-values < 0.05). Four were extracted from CT (CI = 0.61 to 0.63, p-value <0.01) and one from PET which was also the most prognostic (CI = 0.64, p-value <0.001). Conclusion: This study demonstrated significant association between radiomic features and DM for patients with locally advanced lung adenocarcinoma. Moreover, conventional (clinically utilized) metrics were not significantly associated with DM. Radiomics can potentially help classify patients at higher risk of DM, allowing clinicians to individualize treatment, such as intensification of chemotherapy) to reduce the risk of DM and improve survival. R.M. has consulting interests with Amgen.

  12. A Comparison of Several Artificial Neural Network Classifiers for CT Images of Hardwood Logs

    Science.gov (United States)

    Daniel L. Schmoldt; Jing He; A. Lynn Abbott

    1998-01-01

    Knowledge of internal log defects, obtained by scanning, is critical to efficiency improvements for future hardwood sawmills. Nevertheless, before computed tomography (CT) scanning can be applied in industrial operations, we need to automatically interpret scan information so that it can provide the saw operator with the information necessary to make proper sawing...

  13. Comparison of percutaneous radiologic gastrostomy by using cone beam CT and endoscopic gastrostomy

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hyun Nyeong; Han, Young Min; Jin, Gong Yong; Choi, Eun Jeong; Song, Ji Soo [Chonbuk National University Hospital and Medical School, Jeonju (Korea, Republic of)

    2014-01-15

    To compare the effectiveness of percutaneous radiologic gastrostomy (PRG) by using cone beam CT and percutaneous endoscopic gastrostomy (PEG). This study retrospectively reviewed 129 patients who underwent PRG (n = 53) and PEG (n = 76) over a 2-years period. The C-arm cone beam CT images were obtained from all PRG patients before the procedure in order to decide the safest accessing routes. The parameters including technical success rates, complication rates and tube migration rates were all analyzed according to statistical methods. The success rate of tube placement was higher in PRG than in PEG (100% to 93%, p = 0.08). Minor complications occurred in 5 patients of the PRG group (10%; 5/53, 3 wound infection, 2 blood oozing), and occurred in 6 patients of PEG group (7.9%; 6/76, 5 wound infection, 1 esophageal ulcer). Major complications occurred only in 5 patients of PEG group (6.6%; 5/76, 1 panperitonitis, 4 buried bumper syndrome). There were no statistical differences of minor and major complication rates in the two groups (respectively, p = 0.759, p = 0.078). Tube migration rate was lower in PRG than PEG group (7.5% vs. 38.2%, p < 0.005). PRG using cone beam CT is the effective and safe method, the cone beam CT provides the safest accessing route during gastrostomy. Less tube migration occurs in the PRG than in PEG.

  14. Comparison of post contrast CT urography phases in bladder cancer detection.

    Science.gov (United States)

    Helenius, Malin; Dahlman, Par; Lonnemark, Maria; Brekkan, Einar; Wernroth, Lisa; Magnusson, Anders

    2016-02-01

    The aim of this study was to investigate which post-contrast phase(s) in a four-phase CT urography protocol is (are) most suitable for bladder cancer detection. The medical records of 106 patients with visible haematuria who underwent a CT urography examination, including unenhanced, enhancement-triggered corticomedullary (CMP), nephrographic (NP) and excretory (EP) phases, were reviewed. The post-contrast phases (n = 318 different phases) were randomized into an evaluation order and blindly reviewed by two uroradiologists. Twenty-one patients were diagnosed with bladder cancer. Sensitivity for bladder cancer detection was 0.95 in CMP, 0.83 in NP and 0.81 in EP. Negative predictive value (NPV) was 0.99 in CMP, 0.96 in NP and 0.95 in EP. The sensitivity was higher in CMP than in both NP (p-value 0.016) and EP (p-value 0.0003). NPV was higher in CMP than in NP (p-value 0.024) and EP (p-value 0.002). In the CT urography protocol with enhancement-triggered scan, sensitivity and NPV were highest in the corticomedullary phase, and this phase should be used for bladder assessment. • More bladder tumours are detected during the corticomedullary phase than during other phases. • Sensitivity and NPV for bladder cancer detection were highest in corticomedullary phase. • The corticomedullary phase in CT urography should be used for bladder assessment.

  15. Comparison between CT tumor size and pathological tumor size in frozen section examinations of lung adenocarcinoma.

    Science.gov (United States)

    Isaka, Tetsuya; Yokose, Tomoyuki; Ito, Hiroyuki; Imamura, Naoko; Watanabe, Masato; Imai, Kentaro; Nishii, Teppei; Woo, Tetsukan; Yamada, Kouzo; Nakayama, Haruhiko; Masuda, Munetaka

    2014-07-01

    We examined the appropriate measurement for pathological tumor size by comparing radiological and pathological tumor size of resected lung adenocarcinoma in FSE. We reviewed records of 59 resected specimens of lung adenocarcinoma for FSE from January to December 2008. Specimens were well-inflated with saline by using an injector before cutting into segments. After selecting the tumor segment of maximal diameter, we compared three ways of measuring pathological tumor size by using paired t-test: (I) macroscopic tumor size (MTS), measured with a metal straight ruler, (II) microscopic frozen section tumor size (FSTS), and (III) microscopic paraffin section tumor size (PSTS). We compared each discrepancy rate (DR) [DR=(CT tumor size-pathological tumor size)/CT tumor size×100] (%) between tumors that were air-containing type and solid-density type on CT scans, and also compared the tumors with lepidic component rates (LCR) ≥50% and LCR lung specimen must be sufficiently inflated to prevent tissue shrinking, and we propose MTS as the definition for pathological tumor size in FSE. The greater discordance observed between CT tumor size and microscopic tumor size was assumed to be due to shrinkage of the lepidic component in the tumor. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  16. Comparison of CT and CMR for detection and quantification of carotid artery calcification

    DEFF Research Database (Denmark)

    Mujaj, Blerim; Lorza, Andrés M. Arias; van Engelen, Arna

    2017-01-01

    BACKGROUND: Carotid artery atherosclerosis is an important risk factor for stroke. As such, quantitative imaging of carotid artery calcification, as a proxy of atherosclerosis, has become a cornerstone of current stroke research. Yet, population-based data comparing the computed tomography (CT) a...

  17. Chest CT features of cystic fibrosis in Korea: Comparison with non-cystic fibrosis diseases

    Energy Technology Data Exchange (ETDEWEB)

    Yang, So Yeon; Lee, Kyung Soo; Kim, Tae Jung; Kim, Tae Sung [Dept. of Radiology, and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Cha, Min Jae [Dept. of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul (Korea, Republic of); Yoon, Hyun Jung [Dept. of Radiology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul (Korea, Republic of)

    2017-01-15

    Cystic fibrosis (CF) is a rare congenital disease in Korea, and its clinical and imaging findings are unclear. The objective of our study was to describe the clinical and CT features of CF in Korea and compare its features with those of other diseases mimicking CF. From November 1994 to December 2014, a presumptive diagnosis of CF was made in 23 patients based on clinical or radiological examination. After the exclusion of 10 patients without diagnostic confirmation, 13 patients were included in the study. A diagnosis of CF was made with the CF gene study. CT findings were evaluated for the presence and distribution of parenchymal abnormalities including bronchiectasis, tree-in-bud (TIB) pattern, mucus plugging, consolidation, and mosaic attenuation. Of the 13 patients, 7 (median age, 15 years) were confirmed as CF, 4 (median age, 19 years) had primary ciliary dyskinesia, 1 had bronchiectasis of unknown cause, and 1 had chronic asthma. CT of patients with CF showed bilateral bronchiectasis, TIB pattern, mosaic attenuation, and mucus plugging in all patients, with upper lung predominance (57%). In CT of the non-CF patients, bilateral bronchiectasis, TIB pattern, mosaic attenuation, and mucus plugging were also predominant features, with lower lung predominance (50%). Korean patients with CF showed bilateral bronchiectasis, cellular bronchiolitis, mucus plugging, and mosaic attenuation, which overlapped with those of non-CF patients. CF gene study is recommended for the definitive diagnosis of CF in patients with these clinical and imaging features.

  18. Comparison of CT and MRI for Diagnosis of Suspected Scaphoid Fractures

    NARCIS (Netherlands)

    Mallee, W.; Doornberg, J.N.; Ring, D.; van Dijk, C.N.; Maas, M.; Goslings, J.C.

    2011-01-01

    Background: There is no consensus on the optimum imaging method to use to confirm the diagnosis of true scaphoid fractures among patients with suspected scaphoid fractures. This study tested the null hypothesis that computed tomography (CT) and magnetic resonance imaging (MRI) have the same

  19. Iterative metal artefact reduction (MAR) in postsurgical chest CT: comparison of three iMAR-algorithms.

    Science.gov (United States)

    Aissa, Joel; Boos, Johannes; Sawicki, Lino Morris; Heinzler, Niklas; Krzymyk, Karl; Sedlmair, Martin; Kröpil, Patric; Antoch, Gerald; Thomas, Christoph

    2017-11-01

    The purpose of this study was to evaluate the impact of three novel iterative metal artefact (iMAR) algorithms on image quality and artefact degree in chest CT of patients with a variety of thoracic metallic implants. 27 postsurgical patients with thoracic implants who underwent clinical chest CT between March and May 2015 in clinical routine were retrospectively included. Images were retrospectively reconstructed with standard weighted filtered back projection (WFBP) and with three iMAR algorithms (iMAR-Algo1 = Cardiac algorithm, iMAR-Algo2 = Pacemaker algorithm and iMAR-Algo3 = ThoracicCoils algorithm). The subjective and objective image quality was assessed. Averaged over all artefacts, artefact degree was significantly lower for the iMAR-Algo1 (58.9 ± 48.5 HU), iMAR-Algo2 (52.7 ± 46.8 HU) and the iMAR-Algo3 (51.9 ± 46.1 HU) compared with WFBP (91.6 ± 81.6 HU, p algorithms, respectively. iMAR-Algo2 and iMAR-Algo3 reconstructions decreased mild and moderate artefacts compared with WFBP and iMAR-Algo1 (p algorithms led to a significant reduction of metal artefacts and increase in overall image quality compared with WFBP in chest CT of patients with metallic implants in subjective and objective analysis. The iMARAlgo2 and iMARAlgo3 were best for mild artefacts. IMARAlgo1 was superior for severe artefacts. Advances in knowledge: Iterative MAR led to significant artefact reduction and increase image-quality compared with WFBP in CT after implementation of thoracic devices. Adjusting iMAR-algorithms to patients' metallic implants can help to improve image quality in CT.

  20. Tuberculous pneumonia and bacteriaI pneumonia in diabetic patients: comparison of CT findings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yoo Kyung; Shim, Sung Shine [College of Medicine, Chungnam Univ., Daejeon (Korea, Republic of); Kim, Jin Hwan [College of Medicine, Ewha Womans Univ., Seoul (Korea, Republic of)

    2004-07-01

    To compare the CT findings of tuberculous pneumonia (TBPN) with those of bacterial pneumonia (BAPN) in diabetic patients and to evaluate the usefulness of CT in the differential diagnosis of these two diseases. The chest CT scans of 23 diabetic patients with TBPN (M:F=21:2; mean age, 59 yrs.) and of 37 diabetic patients with BAPN (M:F=21:16; mean age, 63 yrs.) were evaluated by two radiologists with regard to low attenuation areas in regions of consolidation, cavities, air bronchogram, volume changes, ground-glass attenuation, findings of bronchogenic spread, and other associated findings. The involvement of each segment was recorded in all patients. The frequencies of multiple small low-attenuation areas in regions of consolidation (52%, 0%), multiple cavities (35%, 3%), loss of volume (70%, 30%) and findings of bronchogenic spread (96%, 30%) were significantly higher in TBPN than in BAPN (p< .05). Low-attenuation masses and bizarre-shaped cavities were noted only in TBPN. Large areas of ground-glass attenuation (4%, 38%) and bilateral pleural effusions (0%, 19%) were more common in BAPN, while air-bronchogram was common in both groups (96%, 86%). The involvement of the superior segment was significantly more common in TBPN (p< .05). In the diabetic patients with pulmonary consolidation, CT findings of multiple small low-attenuation areas, multiple cavities, bizarre-shaped cavities, low attenuation masses in cavities, volume loss, and findings of bronchogenic spread are more suggestive of TBPN, while large areas of ground-glass attenuation and bilateral pleural effusions are more suggestive of BAPN. CT may be useful in the differential diagnosis between TBPN and BAPN.

  1. Cross section and double helicity asymmetry for eta mesons and their comparison to neutral pion production in p+p collisions at sqrt(s)=200 GeV

    CERN Document Server

    Adare, A; Aidala, C; Ajitanand, N N; Akiba, Y; Al-Bataineh, H; Alexander, J; Aoki, K; Aphecetche, L; Armendariz, R; Aronson, S H; Asai, J; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Basye, A T; Bathe, S; Batsouli, S; Baublis, V; Baumann, C; Bazilevsky, A; Belikov, S; Bennett, R; Berdnikov, A; Berdnikov, Y; Bickley, A A; Boissevain, J G; Borel, H; Boyle, K; Brooks, M L; Buesching, H; Bumazhnov, V; Bunce, G; Butsyk, S; Camacho, C M; Campbell, S; Chang, B S; Chang, W C; Charvet, J -L; Chernichenko, S; Chiba, J; Chi, C Y; Chiu, M; Choi, I J; Choudhury, R K; Chujo, T; Chung, P; Churyn, A; Cianciolo, V; Citron, Z; Cleven, C R; Cole, B A; Comets, M P; Constantin, P; Csanád, M; Csörgő, T; Dahms, T; Dairaku, S; Das, K; David, G; Deaton, M B; Dehmelt, K; Delagrange, H; Denisov, A; d'Enterria, D; Deshpande, A; Desmond, E J; Dietzsch, O; Dion, A; Donadelli, M; Drapier, O; Drees, A; Drees, K A; Dubey, A K; Durum, A; Dutta, D; Dzhordzhadze, V; Efremenko, Y V; Egdemir, J; Ellinghaus, F; Emam, W S; Engelmore, T; Enokizono, A; En'yo, H; Esumi, S; Eyser, K O; Fadem, B; Fields, D E; Finger, M; \\,; Jr.,; Finger, M; Fleuret, F; Fokin, S L; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fujiwara, K; Fukao, Y; Fusayasu, T; Gadrat, S; Garishvili, I; Glenn, A; Gong, H; Gonin, M; Gosset, J; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Perdekamp, M Grosse; Gunji, T; Gustafsson, H -Å; Hachiya, T; Henni, A Hadj; Haegemann, C; Haggerty, J S; Hamagaki, H; Han, R; Harada, H; Hartouni, E P; Haruna, K; Haslum, E; Hayano, R; Heffner, M; Hemmick, T K; Hester, T; He, X; Hiejima, H; Hill, J C; Hobbs, R; Hohlmann, M; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hornback, D; Huang, S; Ichihara, T; Ichimiya, R; Iinuma, H; Ikeda, Y; Imai, K; Imrek, J; Inaba, M; Inoue, Y; Isenhower, D; Isenhower, L; Ishihara, M; Isobe, T; Issah, M; Isupov, A; Ivanischev, D; Jacak, B V; Jia, J; Jin, J; Jinnouchi, O; Johnson, B M; Joo, K S; Jouan, D; Kajihara, F; Kametani, S; Kamihara, N; Kamin, J; Kaneta, M; Kang, J H; Kanou, H; Kapustinsky, J; Kawall, D; Kazantsev, A V; Kempel, T; Khanzadeev, A; Kijima, K M; Kikuchi, J; Kim, B I; Kim, D H; Kim, D J; Kim, E; Kim, S H; Kinney, E; Kiriluk, K; Kiss, Á; Kistenev, E; Kiyomichi, A; Klay, J; Klein-Boesing, C; Kochenda, L; Kochetkov, V; Komkov, B; Konno, M; Koster, J; Kotchetkov, D; Kozlov, A; Král, A; Kravitz, A; Kubart, J; Kunde, G J; Kurihara, N; Kurita, K; Kurosawa, M; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y S; Lajoie, J G; Layton, D; Lebedev, A; Lee, D M; Lee, K B; Lee, M K; Lee, T; Leitch, M J; Leite, M A L; Lenzi, B; Liebing, P; Liška, T; Litvinenko, A; Liu, H; Liu, M X; Li, X; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Malakhov, A; Malik, M D; Manko, V I; Mannel, E; Mao, Y; Mašek, L; Masui, H; Matathias, F; McCumber, M; McGaughey, P L; Means, N; Meredith, B; Miake, Y; Mikeš, P; Miki, K; Miller, T E; Milov, A; Mioduszewski, S; Mishra, M; Mitchell, J T; Mitrovski, M; Mohanty, A K; Morino, Y; Morreale, A; Morrison, D P; Moukhanova, T V; Mukhopadhyay, D; Murata, J; Nagamiya, S; Nagata, Y; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakamiya, Y; Nakamura, T; Nakano, K; Newby, J; Nguyen, M; Niita, T; Norman, B E; Nouicer, R; Nyanin, A S; O'Brien, E; Oda, S X; Ogilvie, C A; Ohnishi, H; Okada, K; Oka, M; Omiwade, O O; Onuki, Y; Oskarsson, A; Ouchida, M; Ozawa, K; Pak, R; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, J; Park, W J; Pate, S F; Pei, H; Peng, J -C; Pereira, H; Peresedov, V; Peressounko, D Yu; Pinkenburg, C; Purschke, M L; Purwar, A K; Qu, H; Rak, J; Rakotozafindrabe, A; Ravinovich, I; Read, K F; Rembeczki, S; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roach, D; Roche, G; Rolnick, S D; Romana, A; Rosati, M; Rosendahl, S S E; Rosnet, P; Rukoyatkin, P; Ružička, P; Rykov, V L; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakai, S; Sakashita, K; Sakata, H; Samsonov, V; Sato, S; Sato, T; Sawada, S; Sedgwick, K; Seele, J; Seidl, R; Semenov, A Yu; Semenov, V; Seto, R; Sharma, D; Shein, I; Shevel, A; Shibata, T -A; Shigaki, K; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, B K; Singh, C P; Singh, V; Skutnik, S; Slunečka, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Suire, C; Sukhanov, A; Sziklai, J; Tabaru, T; Takagi, S; Takagui, E M; Taketani, A; Tanabe, R; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Taranenko, A; Tarján, P; Themann, H; Thomas, T L; Togawa, M; Toia, A; Tojo, J; Tomášek, L; Tomita, Y; Torii, H; Towell, R S; Tram, V-N; Tserruya, I; Tsuchimoto, Y; Vale, C; Valle, H; van Hecke, H W; Veicht, A; Velkovska, J; Vértesi, R; Vinogradov, A A; Virius, M; Vrba, V; Vznuzdaev, E; Wagner, M; Walker, D; Wang, X R; Watanabe, Y; Wei, F; Wessels, J; White, S N; Winter, D; Woody, C L; Wysocki, M; Xie, W; Yamaguchi, Y L; Yamaura, K; Yang, R; Yanovich, A; Yasin, Z; Ying, J; Yokkaichi, S; Young, G R; Younus, I; Yushmanov, I E; Zajc, W A; Zaudtke, O; Zhang, C; Zhou, S; Zimányi, J; Zolin, L

    2010-01-01

    Measurements of double-helicity asymmetries for inclusive hadron production in polarized p+p collisions are sensitive to helicity--dependent parton distribution functions, in particular to the gluon helicity distribution, Delta(g). This study focuses on the extraction of the double-helicity asymmetry in eta production: polarized p+p --> eta + X, the eta cross section, and the eta/pi^0 cross section ratio. The cross section and ratio measurements provide essential input for the extraction of fragmentation functions that are needed to access the helicity-dependent parton distribution functions.

  2. Feasibility of epicardial adipose tissue quantification in non-ECG-gated low-radiation-dose CT: comparison with prospectively ECG-gated cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Simon-Yarza, Isabel; Viteri-Ramirez, Guillermo; Saiz-Mendiguren, Ramon; Slon-Roblero, Pedro J.; Paramo, Maria [Dept. of Radiology, Clinica Univ. de Navarra, Pamplona (Spain); Bastarrika, Gorka [Dept. of Radiology, Clinica Univ. de Navarra, Pamplona (Spain); Cardiac Imaging Unit, Clinica Univ. de Navarra, Pamplona (Spain)], e-mail: bastarrika@unav.es

    2012-06-15

    Background: Epicardial adipose tissue (EAT) is an important indicator of cardiovascular risk. This parameter is generally assessed on ECG-gated computed tomography (CT) images. Purpose: To evaluate feasibility and reliability of EAT quantification on non-gated thoracic low-radiation-dose CT examinations with respect to prospectively ECG-gated cardiac CT acquisition. Material and Methods: Sixty consecutive asymptomatic smokers (47 men; mean age 64 {+-} 9.8 years) underwent low-dose CT of the chest and prospectively ECG-gated cardiac CT acquisitions (64-slice dual-source CT). The two examinations were reconstructed with the same range, field of view, slice thickness, and convolution algorithm. Two independent observers blindly quantified EAT volume using commercially available software. Data were compared with paired sample Student t-test, concordance correlation coefficients (CCC), and Bland-Altman plots. Results: No statistically significant difference was observed for EAT volume quantification with low-dose-CT (141.7 {+-} 58.3 mL) with respect to ECG-gated CT (142.7 {+-} 57.9 mL). Estimation of CCC showed almost perfect concordance between the two techniques for EAT-volume assessment (CCC, 0.99; mean difference, 0.98 {+-} 5.1 mL). Inter-observer agreement for EAT volume estimation was CCC: 0.96 for low-dose-CT examinations and 0.95 for ECG-gated CT. Conclusion: Non-gated low-dose CT allows quantifying EAT with almost the same concordance and reliability as using dedicated prospectively ECG-gated cardiac CT acquisition protocols.

  3. Improved CT Detection of Acute Herpes Simplex Virus Type 1 Encephalitis Based on a Frequency-Selective Nonlinear Blending: Comparison With MRI.

    Science.gov (United States)

    Bongers, Malte Niklas; Bier, Georg; Ditt, Hendrik; Beck, Robert; Ernemann, Ulrike; Nikolaou, Konstantin; Horger, Marius

    2016-11-01

    The purpose of this study is to compare the diagnostic efficacy of a new CT postprocessing tool based on frequency-selective nonlinear blending (best-contrast CT) with that of standard linear blending of unenhanced head CT in patients with herpes simplex virus type 1 and herpes simplex virus encephalitis (HSE), using FLAIR MRI sequences as the standard of reference. Fifteen consecutive patients (six women and nine men; mean [± SD] age, 60 ± 19 years) with proven HSE (positive polymerase chain reaction results from CSF analysis and the presence of neurologic deficits) were retrospectively enrolled. All patients had undergone head CT and MRI (mean time interval, 2 ± 2 days). After standardized unenhanced head CT scans were read, presets of the best-contrast algorithm were determined (center, 30 HU; delta, 5 HU; slope, 5 nondimensional), and resulting images were analyzed. Contrast enhancement was objectively measured by ROI analysis, comparing contrast-to-noise ratios (CNRs) of unenhanced CT and best-contrast CT. FLAIR and DWI MRI sequences were analyzed, and FLAIR was considered as the standard of reference. For assessment of disease extent, a previously reported 50-point score (HSE score) was used. CNR values for unenhanced head CT (CNR, 5.42 ± 2.77) could be statistically significantly increased using best-contrast CT (CNR, 9.62 ± 4.28) (p = 0.003). FLAIR sequences yielded a median HSE score of 9.0 (range, 6-17) and DWI sequences yielded HSE scores of 6.0 (range, 5-17). By comparison, unenhanced head CT resulted in a median HSE score of 3.5 (range, 1-6). The median best-contrast CT HSE score was 7.5 (range, 6-10). Agreement between FLAIR and unenhanced CT was 54.44%, that between DWI and best-contrast CT was 95.36%, and that between FLAIR and best-contrast CT was 85.21%. The most frequently overseen findings were located at the level of the upper part of the mesencephalon and at the subthalamic or insular level. Frequency-selective nonlinear blending

  4. Diagnostic performance of a CT-based scoring system for diagnosis of anastomotic leakage after esophagectomy: comparison with subjective CT assessment

    Energy Technology Data Exchange (ETDEWEB)

    Goense, Lucas; Rossum, Peter S.N. van [University Medical Center Utrecht, Department of Surgery, Utrecht (Netherlands); University Medical Center Utrecht, Department of Radiation Oncology, Utrecht (Netherlands); Stassen, Pauline M.C.; Ruurda, Jelle P.; Hillegersberg, Richard van [University Medical Center Utrecht, Department of Surgery, Utrecht (Netherlands); Wessels, Frank J.; Leeuwen, Maarten S. van [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands)

    2017-10-15

    To develop a CT-based prediction score for anastomotic leakage after esophagectomy and compare it to subjective CT interpretation. Consecutive patients who underwent a CT scan for a clinical suspicion of anastomotic leakage after esophagectomy with cervical anastomosis between 2003 and 2014 were analyzed. The CT scans were systematically re-evaluated by two radiologists for the presence of specific CT findings and presence of an anastomotic leak. Also, the original CT interpretations were acquired. These results were compared to patients with and without a clinical confirmed leak. Out of 122 patients that underwent CT for a clinical suspicion of anastomotic leakage; 54 had a confirmed leak. In multivariable analysis, anastomotic leakage was associated with mediastinal fluid (OR = 3.4), esophagogastric wall discontinuity (OR = 4.9), mediastinal air (OR = 6.6), and a fistula (OR = 7.2). Based on these criteria, a prediction score was developed resulting in an area-under-the-curve (AUC) of 0.86, sensitivity of 80%, and specificity of 84%. The original interpretation and the systematic subjective CT assessment by two radiologists resulted in AUCs of 0.68 and 0.75 with sensitivities of 52% and 69%, and specificities of 84% and 82%, respectively. This CT-based score may provide improved diagnostic performance for diagnosis of anastomotic leakage after esophagectomy. (orig.)

  5. Helices and vector bundles

    CERN Document Server

    Rudakov, A N

    1990-01-01

    This volume is devoted to the use of helices as a method for studying exceptional vector bundles, an important and natural concept in algebraic geometry. The work arises out of a series of seminars organised in Moscow by A. N. Rudakov. The first article sets up the general machinery, and later ones explore its use in various contexts. As to be expected, the approach is concrete; the theory is considered for quadrics, ruled surfaces, K3 surfaces and P3(C).

  6. Characteristic of muscle involvement evaluated by CT scans in early stages of progressive muscular dystrophy; Comparison between Duchenne and Fukuyama types

    Energy Technology Data Exchange (ETDEWEB)

    Arai, Yumi (Tokyo Women' s Medical Coll. (Japan))

    1993-10-01

    Muscle CT scans were performed in order to compare the characteristic distribution of progressive muscle involvement in the early stages of Duchenne type (DMD) and Fukuyama type muscular dystrophy (FCMD). Muscle images at the levels of the 3rd lumbar vertebra, thigh and calf were assessed by visual inspection, and mean CT numbers calculated for individual muscles were statistically analysed. On visual inspection, intramuscular low density areas and muscular atrophy were observed in the muscles of older patients with either disease. These changes were, however, more extensive at thigh level in DMD, and at calf level in FCMD. Nevertheless, the mean CT numbers of muscles in which only slight changes were grossly visible on CT scans displayed progressive decreases with increasing age. Moreover, a significant negative relationship was recognizable between age and mean CT number in almost all muscles examined. Comparison of the slopes of the regression lines revealed that the so-called selective pattern of muscle involvement characteristic of the symptomatic stage had already partially manifested in the preclinical or early stages of both diseases. In FCMD, the rates of decrease in CT numbers were extremely rapid for calf muscles as compared with those in DMD, indicating that this is one reason for FCMD patients never becoming ambulatory. However, for almost all of the other muscles, the CT numbers in FCMD decreased in parallel with the corresponding CT numbers in DMD; thus, these diseases displayed a similarity in the pattern of muscle involvement, despite their different pathogenetic mechanisms and inheritance patterns. (author).

  7. Comparison study of the partial-breast irradiation techniques: Dosimetric analysis of three-dimensional conformal radiation therapy, electron beam therapy, and helical tomotherapy depending on various tumor locations

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min-Joo; Park, So-Hyun [Department of Biomedical Engineering, The Catholic University of Korea, Seoul (Korea, Republic of); Research Institute of Biomedical Engineering, The Catholic University of Korea, Seoul (Korea, Republic of); Son, Seok-Hyun; Cheon, Keum-Seong; Choi, Byung-Ock [Department of Radiation Oncology, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul (Korea, Republic of); Suh, Tae-Suk, E-mail: suhsanta@catholic.ac.kr [Department of Biomedical Engineering, The Catholic University of Korea, Seoul (Korea, Republic of); Research Institute of Biomedical Engineering, The Catholic University of Korea, Seoul (Korea, Republic of)

    2013-10-01

    The partial-breast irradiation (PBI) technique, an alternative to whole-breast irradiation, is a beam delivery method that uses a limited range of treatment volume. The present study was designed to determine the optimal PBI treatment modalities for 8 different tumor locations. Treatment planning was performed on computed tomography (CT) data sets of 6 patients who had received lumpectomy treatments. Tumor locations were classified into 8 subsections according to breast quadrant and depth. Three-dimensional conformal radiation therapy (3D-CRT), electron beam therapy (ET), and helical tomotherapy (H-TOMO) were utilized to evaluate the dosimetric effect for each tumor location. Conformation number (CN), radical dose homogeneity index (rDHI), and dose delivered to healthy tissue were estimated. The Kruskal-Wallis, Mann-Whitney U, and Bonferroni tests were used for statistical analysis. The ET approach showed good sparing effects and acceptable target coverage for the lower inner quadrant—superficial (LIQ-S) and lower inner quadrant—deep (LIQ-D) locations. The H-TOMO method was the least effective technique as no evaluation index achieved superiority for all tumor locations except CN. The ET method is advisable for treating LIQ-S and LIQ-D tumors, as opposed to 3D-CRT or H-TOMO, because of acceptable target coverage and much lower dose applied to surrounding tissue.

  8. The relevance of MRI for patient modeling in head and neck hyperthermia treatment planning: A comparison of CT and CT-MRI based tissue segmentation on simulated temperature

    Energy Technology Data Exchange (ETDEWEB)

    Verhaart, René F., E-mail: r.f.verhaart@erasmusmc.nl; Paulides, Margarethus M. [Hyperthermia Unit, Department of Radiation Oncology, Erasmus MC - Cancer Institute, Groene Hilledijk 301, Rotterdam 3008 AE (Netherlands); Fortunati, Valerio; Walsum, Theo van; Veenland, Jifke F. [Biomedical Imaging Group of Rotterdam, Department of Medical Informatics and Radiology, Erasmus MC, Dr. Molewaterplein 50/60, Rotterdam 3015 GE (Netherlands); Verduijn, Gerda M. [Department of Radiation Oncology, Erasmus MC - Cancer Institute, Groene Hilledijk 301, Rotterdam 3008 AE (Netherlands); Lugt, Aad van der [Department of Radiology, Erasmus MC, Dr. Molewaterplein 50/60, Rotterdam 3015 GE (Netherlands)

    2014-12-15

    Purpose: In current clinical practice, head and neck (H and N) hyperthermia treatment planning (HTP) is solely based on computed tomography (CT) images. Magnetic resonance imaging (MRI) provides superior soft-tissue contrast over CT. The purpose of the authors’ study is to investigate the relevance of using MRI in addition to CT for patient modeling in H and N HTP. Methods: CT and MRI scans were acquired for 11 patients in an immobilization mask. Three observers manually segmented on CT, MRI T1 weighted (MRI-T1w), and MRI T2 weighted (MRI-T2w) images the following thermo-sensitive tissues: cerebrum, cerebellum, brainstem, myelum, sclera, lens, vitreous humor, and the optical nerve. For these tissues that are used for patient modeling in H and N HTP, the interobserver variation of manual tissue segmentation in CT and MRI was quantified with the mean surface distance (MSD). Next, the authors compared the impact of CT and CT and MRI based patient models on the predicted temperatures. For each tissue, the modality was selected that led to the lowest observer variation and inserted this in the combined CT and MRI based patient model (CT and MRI), after a deformable image registration. In addition, a patient model with a detailed segmentation of brain tissues (including white matter, gray matter, and cerebrospinal fluid) was created (CT and MRI{sub db}). To quantify the relevance of MRI based segmentation for H and N HTP, the authors compared the predicted maximum temperatures in the segmented tissues (T{sub max}) and the corresponding specific absorption rate (SAR) of the patient models based on (1) CT, (2) CT and MRI, and (3) CT and MRI{sub db}. Results: In MRI, a similar or reduced interobserver variation was found compared to CT (maximum of median MSD in CT: 0.93 mm, MRI-T1w: 0.72 mm, MRI-T2w: 0.66 mm). Only for the optical nerve the interobserver variation is significantly lower in CT compared to MRI (median MSD in CT: 0.58 mm, MRI-T1w: 1.27 mm, MRI-T2w: 1.40 mm

  9. Comparison of adaptive statistical iterative and filtered back projection reconstruction techniques in brain CT

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Qingguo, E-mail: renqg83@163.com [Department of Radiology, Hua Dong Hospital of Fudan University, Shanghai 200040 (China); Dewan, Sheilesh Kumar, E-mail: sheilesh_d1@hotmail.com [Department of Geriatrics, Hua Dong Hospital of Fudan University, Shanghai 200040 (China); Li, Ming, E-mail: minli77@163.com [Department of Radiology, Hua Dong Hospital of Fudan University, Shanghai 200040 (China); Li, Jianying, E-mail: Jianying.Li@med.ge.com [CT Imaging Research Center, GE Healthcare China, Beijing (China); Mao, Dingbiao, E-mail: maodingbiao74@163.com [Department of Radiology, Hua Dong Hospital of Fudan University, Shanghai 200040 (China); Wang, Zhenglei, E-mail: Williswang_doc@yahoo.com.cn [Department of Radiology, Shanghai Electricity Hospital, Shanghai 200050 (China); Hua, Yanqing, E-mail: cjr.huayanqing@vip.163.com [Department of Radiology, Hua Dong Hospital of Fudan University, Shanghai 200040 (China)

    2012-10-15

    Purpose: To compare image quality and visualization of normal structures and lesions in brain computed tomography (CT) with adaptive statistical iterative reconstruction (ASIR) and filtered back projection (FBP) reconstruction techniques in different X-ray tube current–time products. Materials and methods: In this IRB-approved prospective study, forty patients (nineteen men, twenty-one women; mean age 69.5 ± 11.2 years) received brain scan at different tube current–time products (300 and 200 mAs) in 64-section multi-detector CT (GE, Discovery CT750 HD). Images were reconstructed with FBP and four levels of ASIR-FBP blending. Two radiologists (please note that our hospital is renowned for its geriatric medicine department, and these two radiologists are more experienced in chronic cerebral vascular disease than in neoplastic disease, so this research did not contain cerebral tumors but as a discussion) assessed all the reconstructed images for visibility of normal structures, lesion conspicuity, image contrast and diagnostic confidence in a blinded and randomized manner. Volume CT dose index (CTDI{sub vol}) and dose-length product (DLP) were recorded. All the data were analyzed by using SPSS 13.0 statistical analysis software. Results: There was no statistically significant difference between the image qualities at 200 mAs with 50% ASIR blending technique and 300 mAs with FBP technique (p > .05). While between the image qualities at 200 mAs with FBP and 300 mAs with FBP technique a statistically significant difference (p < .05) was found. Conclusion: ASIR provided same image quality and diagnostic ability in brain imaging with greater than 30% dose reduction compared with FBP reconstruction technique.

  10. Micro-CT Comparison of Posterior Composite Resin Restorative Techniques: Sonicated versus Incremental Fill

    Science.gov (United States)

    2015-06-01

    the measurement of enamel thickness, root canal morphology and preparation, micro finite element modeling, dental tissue engineering and mineral...vertical sections of prepared teeth . It was concluded that the syringe technique had better adaptation and fewer voids. Recently, micro-CT analysis was...shrinkage and leakage in extracted teeth using X-ray microcomputed tomography. Dent Mater. 2009;25:1213-1220. 24. Kakaboura A, Rahiotis C, WattsD

  11. Comparison of post contrast CT urography phases in bladder cancer detection

    Energy Technology Data Exchange (ETDEWEB)

    Helenius, Malin; Dahlman, Par; Lonnemark, Maria; Magnusson, Anders [Uppsala University Hospital, Department of Surgical Sciences, Section of Radiology, Uppsala (Sweden); Brekkan, Einar [Uppsala University Hospital, Department of Surgical Sciences, Section of Urology, Uppsala (Sweden); Wernroth, Lisa [Uppsala University Hospital, Uppsala Clinical Research Center, Uppsala (Sweden)

    2016-02-15

    The aim of this study was to investigate which post-contrast phase(s) in a four-phase CT urography protocol is (are) most suitable for bladder cancer detection. The medical records of 106 patients with visible haematuria who underwent a CT urography examination, including unenhanced, enhancement-triggered corticomedullary (CMP), nephrographic (NP) and excretory (EP) phases, were reviewed. The post-contrast phases (n = 318 different phases) were randomized into an evaluation order and blindly reviewed by two uroradiologists. Twenty-one patients were diagnosed with bladder cancer. Sensitivity for bladder cancer detection was 0.95 in CMP, 0.83 in NP and 0.81 in EP. Negative predictive value (NPV) was 0.99 in CMP, 0.96 in NP and 0.95 in EP. The sensitivity was higher in CMP than in both NP (p-value 0.016) and EP (p-value 0.0003). NPV was higher in CMP than in NP (p-value 0.024) and EP (p-value 0.002). In the CT urography protocol with enhancement-triggered scan, sensitivity and NPV were highest in the corticomedullary phase, and this phase should be used for bladder assessment. (orig.)

  12. Trapezium Bone Density—A Comparison of Measurements by DXA and CT

    Directory of Open Access Journals (Sweden)

    Sebastian Breddam Mosegaard

    2018-01-01

    Full Text Available Bone density may influence the primary fixation of cementless implants, and poor bone density may increase the risk of implant failure. Before deciding on using total joint replacement as treatment in osteoarthritis of the trapeziometacarpal joint, it is valuable to determine the trapezium bone density. The aim of this study was to: (1 determine the correlation between measurements of bone mineral density of the trapezium obtained by dual-energy X-ray absorptiometry (DXA scans by a circumference method and a new inner-ellipse method; and (2 to compare those to measurements of bone density obtained by computerized tomography (CT-scans in Hounsfield units (HU. We included 71 hands from 59 patients with a mean age of 59 years (43–77. All patients had Eaton–Glickel stage II–IV trapeziometacarpal (TM joint osteoarthritis, were under evaluation for trapeziometacarpal total joint replacement, and underwent DXA and CT wrist scans. There was an excellent correlation (r = 0.94 between DXA bone mineral density measures using the circumference and the inner-ellipse method. There was a moderate correlation between bone density measures obtained by DXA- and CT-scans with (r = 0.49 for the circumference method, and (r = 0.55 for the inner-ellipse method. DXA may be used in pre-operative evaluation of the trapezium bone quality, and the simpler DXA inner-ellipse measurement method can replace the DXA circumference method in estimation of bone density of the trapezium.

  13. Trapezium Bone Density-A Comparison of Measurements by DXA and CT.

    Science.gov (United States)

    Breddam Mosegaard, Sebastian; Breddam Mosegaard, Kamille; Bouteldja, Nadia; Bæk Hansen, Torben; Stilling, Maiken

    2018-01-18

    Bone density may influence the primary fixation of cementless implants, and poor bone density may increase the risk of implant failure. Before deciding on using total joint replacement as treatment in osteoarthritis of the trapeziometacarpal joint, it is valuable to determine the trapezium bone density. The aim of this study was to: (1) determine the correlation between measurements of bone mineral density of the trapezium obtained by dual-energy X-ray absorptiometry (DXA) scans by a circumference method and a new inner-ellipse method; and (2) to compare those to measurements of bone density obtained by computerized tomography (CT)-scans in Hounsfield units (HU). We included 71 hands from 59 patients with a mean age of 59 years (43-77). All patients had Eaton-Glickel stage II-IV trapeziometacarpal (TM) joint osteoarthritis, were under evaluation for trapeziometacarpal total joint replacement, and underwent DXA and CT wrist scans. There was an excellent correlation (r = 0.94) between DXA bone mineral density measures using the circumference and the inner-ellipse method. There was a moderate correlation between bone density measures obtained by DXA- and CT-scans with (r = 0.49) for the circumference method, and (r = 0.55) for the inner-ellipse method. DXA may be used in pre-operative evaluation of the trapezium bone quality, and the simpler DXA inner-ellipse measurement method can replace the DXA circumference method in estimation of bone density of the trapezium.

  14. Comparison of different patient positioning strategies to minimize shoulder girdle artifacts in head and neck CT

    Energy Technology Data Exchange (ETDEWEB)

    Wirth, Stefan; Meindl, Thomas; Treitl, Marcus; Pfeifer, K.J.; Reiser, Maximilian [University of Munich, Department of Clinical Radiology, Munich (Germany)

    2006-08-15

    The purpose of this study was to analyze different patient positioning strategies for minimizing artifacts of the shoulder girdle in head and neck CT. Standardized CT examinations of three positioning groups were compared (P: patients pushed their shoulders downwards; D: similar optimization by a pulling device; N: no particular positioning optimization). Parameters analyzed were the length of the cervical spine not being superimposed by the shoulder girdle as well as noise in the supraclavicular space. In groups P and D, the portion of the cervical spine not superimposed was significantly larger than in group N (P: 10.4 cm; D: 10.6 cm; N: 8.5 cm). At the supraclavicular space, noise decreased significantly (P: 12.5 HU; D: 12.1 HU; N: 17.7 HU). No significant differences between the two position-optimized groups (P and D) were detected. Optimized shoulder positioning by the patient increases image quality in CT head and neck imaging. The use of a pulling device offers no additional advantages. (orig.)

  15. Quantitative carotid PET/MR imaging: clinical evaluation of MR-Attenuation correction versus CT-Attenuation correction in 18F-FDG PET/MR emission data and comparison to PET/CT

    OpenAIRE

    Bini, Jason; Robson, Philip M.; Calcagno, Claudia; Eldib, Mootaz; Fayad, Zahi A.

    2015-01-01

    Current PET/MR systems employ segmentation of MR images and subsequent assignment of empirical attenuation coefficients for quantitative PET reconstruction. In this study we examine the differences in the quantification of 18F-FDG uptake in the carotid arteries between PET/MR and PET/CT scanners. Five comparisons were performed to asses differences in PET quantification: i) PET/MR MR-based AC (MRAC) versus PET/MR CTAC, ii) PET/MR MRAC versus PET/CT, iii) PET/MR MRAC with carotid coil versus P...

  16. Pleural changes after talc pleurodesis in patients with underlying malignancy: Comparison with recurrent malignant pleural lesions on CT and fluorodeoxyglucose-positron emission tomography/CT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Beom Soo; Kang, Hee; Park, Jung Gu [Dept. of Radiology, Kosin University Gospel Hospital, Busan (Korea, Republic of)

    2014-01-15

    To compare computed tomography (CT) and fluorodeoxyglucose-positron emission tomography/CT (FDG-PET/CT) findings of benign pleural changes with those of recurrent malignant pleural lesions in patients with a history of underlying malignancy after talc pleurodesis. Of 194 patients who underwent talc pleurodesis, we retrospectively reviewed 16 patients for whom both follow-up CT and FDG-PET/CT were performed. The morphologic CT findings and maximum standard uptake values (SUVmax) were evaluated and compared between benign pleural changes and recurrent malignant pleural lesions. Twenty-two lesions were found in 16 patients; six patients had no evidence of active pleural disease (group 1) and 10 patients had recurrent malignant pleural lesions on radiological or clinical follow-up (group 2). Characteristic high-density pleural deposits [mean, 131 Hounsfield unit (HU); range, 28-251 HU] were seen along the pleural thickenings (mean, 13.4 mm; range, 4.9-62.3 mm) in 15 patients. The shape and thickness on CT and the SUVmax on FDG-PET/CT showed no significant differences between the two groups. On CT, the pre-contrast attenuation was higher in group 1 than group 2 (165 HU vs. 101 HU, respectively, p = 0.030), and the degree of enhancement was higher in group 2 than that in group 1 (29 HU vs. 48 HU, respectively, p = 0.048). Pleural effusions (n = 5) and other pleural thickening without high-density foci (n = 4) were observed only in group 2; however, no statistical significance was observed between the two groups. Malignant pleural lesions can be characterized by lower pre-contrast attenuation and higher contrast enhancement, whereas benign pleural changes after talc pleurodesis are characterized by higher pre-contrast attenuation and lower contrast enhancement on CT.

  17. Single-energy metal artifact reduction for helical computed tomography of the pelvis in patients with metal hip prostheses.

    Science.gov (United States)

    Yasaka, Koichiro; Maeda, Eriko; Hanaoka, Shouhei; Katsura, Masaki; Sato, Jiro; Ohtomo, Kuni

    2016-09-01

    To compare the quality of helical computed tomography (CT) images of the pelvis in patients with metal hip prostheses reconstructed using adaptive iterative dose reduction (AIDR) and AIDR with single-energy metal artifact reduction (SEMAR-A). This retrospective study included 28 patients (mean age, 64.6 ± 11.4 years; 6 men and 22 women). CT images were reconstructed using AIDR and SEMAR-A. Two radiologists evaluated the extent of metal artifacts and the depiction of structures in the pelvic region and looked for mass lesions. A radiologist placed a region of interest within the bladder and recorded CT attenuation. The metal artifacts were significantly reduced in SEMAR-A as compared to AIDR (p < 0.0001). The depictions of the bladder, ureter, prostate/uterus, rectum, and pelvic sidewall were significantly better with SEMAR-A than with AIDR (p < 0.02). All lesions were diagnosed with SEMAR-A, while some were not diagnosed with AIDR. The median and interquartile range (in parentheses) of CT attenuation within the bladder for AIDR were -34.0 (-46.6 to -15.0) Hounsfield units (HU) and were more variable than those seen for SEMAR-A [5.4 (-1.3 to 11.1)] HU (p = 0.033). In comparison with AIDR, SEMAR-A provided pelvic CT images of significantly better quality for patients with metal hip prostheses.

  18. (68)Ga-DOTA-NOC PET/CT in comparison with CT for the detection of bone metastasis in patients with neuroendocrine tumours.

    Science.gov (United States)

    Ambrosini, Valentina; Nanni, Cristina; Zompatori, Maurizio; Campana, Davide; Tomassetti, Paola; Castellucci, Paolo; Allegri, Vincenzo; Rubello, Domenico; Montini, Giancarlo; Franchi, Roberto; Fanti, Stefano

    2010-04-01

    To retrospectively evaluate the sensitivity, specificity and accuracy of (68)Ga-DOTA-NOC PET/CT and CT alone for the evaluation of bone metastasis in patients with neuroendocrine tumour (NET). From among patients with NET who underwent (68)Ga-DOTA-NOC PET/CT between April 2006 and November 2008 in our centre, 223 were included in the study. Criteria for inclusion were pathological confirmation of NET and a follow-up period of at least 10 months. PET and CT images were retrospectively reviewed by two nuclear medicine specialists and two radiologists, respectively, without knowledge of the patient history or the findings of other imaging modalities. PET data were compared with the CT findings. Interobserver agreement was evaluated in terms of the kappa score. Clinical and imaging follow-up were used as the standard of reference to evaluate the PET findings. PET was performed for staging (49/223), unknown primary tumour detection (24/223), restaging (32/223), restaging before radioimmunotherapy (1/223), evaluation during therapy (12/223), equivocal findings on conventional imaging (4/223 at the bone level; 61/223 at sites other than bone), and follow-up (40/223). A very high interobserver agreement was observed. CT detected at least one bone lesion in only 35 of 44 patients with a positive PET scan. In particular, PET showed more lesions in 20/35 patients, a lower number of lesions in 8/35, and the same number in 7/35. The characteristics of the lesions (sclerotic, lytic, mixed) on the basis of the CT report did not influence PET reading. PET revealed the presence of at least one bone metastasis in nine patients with a negative CT scan. Considering patients with a negative PET scan (179), CT showed equivocal findings at the bone level in three (single small sclerotic abnormality in two at the spine level, and bilateral small sclerotic abnormalities in the humeri, femurs and scapula). Clinical follow-up confirmed the PET findings in all patients; thus there were no

  19. {sup 68}Ga-DOTA-NOC PET/CT in comparison with CT for the detection of bone metastasis in patients with neuroendocrine tumours

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosini, Valentina; Nanni, Cristina; Castellucci, Paolo; Allegri, Vincenzo; Montini, Giancarlo; Franchi, Roberto [S. Orsola-Malpighi University Hospital, Department of Nuclear Medicine, Bologna (Italy); Zompatori, Maurizio [S. Orsola-Malpighi University Hospital, Department of Radiology, Bologna (Italy); Campana, Davide; Tomassetti, Paola [S. Orsola-Malpighi University Hospital, Department of Internal Medicine, Bologna (Italy); Rubello, Domenico [S. Maria della Misericordia Hospital, Department of Nuclear Medicine, Rovigo (Italy); Fanti, Stefano [S. Orsola-Malpighi University Hospital, Department of Nuclear Medicine, Bologna (Italy); Azienda Ospedaliero Universitaria di Bologna, Unita Operativa di Medicina Nucleare, Padiglione 30, Policlinico S.Orsola-Malpighi, Bologna (Italy)

    2010-04-15

    To retrospectively evaluate the sensitivity, specificity and accuracy of {sup 68}Ga-DOTA-NOC PET/CT and CT alone for the evaluation of bone metastasis in patients with neuroendocrine tumour (NET). From among patients with NET who underwent {sup 68}Ga-DOTA-NOC PET/CT between April 2006 and November 2008 in our centre, 223 were included in the study. Criteria for inclusion were pathological confirmation of NET and a follow-up period of at least 10 months. PET and CT images were retrospectively reviewed by two nuclear medicine specialists and two radiologists, respectively, without knowledge of the patient history or the findings of other imaging modalities. PET data were compared with the CT findings. Interobserver agreement was evaluated in terms of the kappa score. Clinical and imaging follow-up were used as the standard of reference to evaluate the PET findings. PET was performed for staging (49/223), unknown primary tumour detection (24/223), restaging (32/223), restaging before radioimmunotherapy (1/223), evaluation during therapy (12/223), equivocal findings on conventional imaging (4/223 at the bone level; 61/223 at sites other than bone), and follow-up (40/223). A very high interobserver agreement was observed. CT detected at least one bone lesion in only 35 of 44 patients with a positive PET scan. In particular, PET showed more lesions in 20/35 patients, a lower number of lesions in 8/35, and the same number in 7/35. The characteristics of the lesions (sclerotic, lytic, mixed) on the basis of the CT report did not influence PET reading. PET revealed the presence of at least one bone metastasis in nine patients with a negative CT scan. Considering patients with a negative PET scan (179), CT showed equivocal findings at the bone level in three (single small sclerotic abnormality in two at the spine level, and bilateral small sclerotic abnormalities in the humeri, femurs and scapula). Clinical follow-up confirmed the PET findings in all patients; thus there

  20. Diagnosing and quantification of acute alcohol intoxication. Comparison of dual-energy CT with biochemical analysis. Initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Korkusuz, H. [Frankfurt Univ. Hospital (Germany). Dept. of Nuclear Medicine; Abbas Raschidi, B.; Keese, D.; Kromen, W.; Bauer, R.W.; Vogl, T.J. [Frankfurt Univ. Hospital (Germany). Dept. of Diagnostic and Interventional Radiology; Namgaladze, D. [Frankfurt Univ. (Germany). Dept. of Biochemistry

    2012-12-15

    Purpose: To quantify the correlation between fat content of an acute alcohol intoxication and the difference of computer tomography attenuation value in dual-energy CT in comparison to biochemical triglyceride analysis and to evaluate qualitatively the value of DECT in the diagnosis of fatty liver caused by ethanol-dosage in rats. Materials and Methods: DECT at 140 kV and 80 kV was performed on 20 rats before and two days after the administration of 3 ml of 50 % ethanol. The CT attenuation value in the livers at 140 kV, 80 kV and the differences between them in Hounsfield units ({Delta}H) were collected. Parts of the liver (100 mg) were measured in biochemical triglyceride analysis as the reference standard. A blood sample was also taken to measure specific liver enzymes. Results: Linear correlation between biochemical triglyceride analysis and CT density of {Delta}H was found (r = 0.949). 140 kV attenuation data were between 44 HU and 61.3 HU, 80 kV attenuation data were between 58.4 HU and 64.7 HU, and {Delta}H data were between 3.4 HU and 14.4 HU (p {<=} 0.037). The biochemical triglyceride analysis data were between 7.1 mg/g and 41.1 mg/g. The hepatic enzymes serum aspartate (ASAT) aminotransferase and alanine aminotransferase (ALAT) were elevated in all rats. ASAT correlated directly with {Delta}HU (r = -0.86). Conclusion: DECT provides a non-invasive method to determine and evaluate hepatic fat content after acute alcohol intoxication. It provides the possibility to detect and quantify the hepatic fat content of liver graft. (orig.)

  1. Estimated risk of radiation-induced cancer from paediatric chest CT: two-year cohort study

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, Tilo [Cantonal Hospital Baden, Department of Radiology, Baden (Switzerland); University Lille Nord de France, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Colas, Lucie; Santangelo, Teresa; Faivre, Jean Baptiste; Remy, Jacques; Remy-Jardin, Martine [University Lille Nord de France, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Roser, Hans W.; Bremerich, Jens [University of Basel Hospital, Clinic of Radiology and Nuclear Medicine, Medical Physics, Basel (Switzerland)

    2015-03-01

    The increasing absolute number of paediatric CT scans raises concern about the safety and efficacy and the effects of consecutive diagnostic ionising radiation. To demonstrate a method to evaluate the lifetime attributable risk of cancer incidence/mortality due to a single low-dose helical chest CT in a two-year patient cohort. A two-year cohort of 522 paediatric helical chest CT scans acquired using a dedicated low-dose protocol were analysed retrospectively. Patient-specific estimations of radiation doses were modelled using three different mathematical phantoms. Per-organ attributable cancer risk was then estimated using epidemiological models. Additional comparison was provided for naturally occurring risks. Total lifetime attributable risk of cancer incidence remains low for all age and sex categories, being highest in female neonates (0.34%). Summation of all cancer sites analysed raised the relative lifetime attributable risk of organ cancer incidence up to 3.6% in female neonates and 2.1% in male neonates. Using dedicated scan protocols, total lifetime attributable risk of cancer incidence and mortality for chest CT is estimated low for paediatric chest CT, being highest for female neonates. (orig.)

  2. Preliminary study of 11C-choline PET/CT for T staging of locally advanced nasopharyngeal carcinoma: comparison with 18F-FDG PET/CT.

    Science.gov (United States)

    Wu, Hu-bing; Wang, Quan-shi; Wang, Ming-fang; Zhen, Xiaokang; Zhou, Wen-lan; Li, Hong-sheng

    2011-03-01

    Evaluation of nasopharyngeal carcinoma (NPC) using (18)F-FDG PET/CT is limited by the intense physiologic uptake of (18)F-FDG in the brain. We attempted to improve detection of intracranial tumor invasion (including better delineation of invasion near the skull base) in locally advanced NPC using(11)C-choline PET/CT. Fifteen patients with newly diagnosed or recurrent locally advanced NPC were enrolled in the study. (18)F-FDG and (11)C-choline PET/CT was performed on all patients. PET/CT images obtained using the 2 tracers were compared using both maximum standardized uptake value (SUVmax) and tumor-to-brain (T/B) ratios. All patients were followed up for more than 1 y. The sensitivity of (18)F-FDG PET/CT in detecting locally advanced NPC was 86.6%, compared with a 100% sensitivity for (11)C-choline PET/CT (t = 2.143, P = 0.483). The SUVmax of lesions detected was higher using (18)F-FDG than using (11)C-choline (12.81 ± 5.00 vs. 6.84 ± 2.76, t = 6.416, P 18)F-FDG (18.62 ± 7.95 vs. 1.38 ± 0.59, t = 8.801, P 18)F-FDG PET/CT, (11)C-choline PET/CT improved the delineation of intracranial invasion in 6 of 12 patients (χ(2) = 8.00, P = 0.014), skull base invasion in 4 of 14 patients, and orbital invasion in 3 of 3 patients. (11)C-choline can improve the quality of PET/CT in the T staging of NPC.

  3. DNA damage in lymphocytes induced by cardiac CT and comparison with physical exposure parameters

    Energy Technology Data Exchange (ETDEWEB)

    Fukumoto, Wataru; Tatsugami, Fuminari; Awai, Kazuo [Department of Diagnostic Radiology, Institute of Biomedical Health Sciences, Hiroshima University, Hiroshima (Japan); Ishida, Mari; Sakai, Chiemi [Institute of Biomedical and Health Sciences, Department of Cardiovascular Physiology and Medicine, Hiroshima University, Hiroshima (Japan); Tashiro, Satoshi [Hiroshima University, Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima (Japan); Ishida, Takafumi [Institute of Clinical Research West Medical Center, Hiroshima (Japan); Nakano, Yukiko [Hiroshima University Hospital, Department of Cardiovascular Medicine, Hiroshima (Japan)

    2017-04-15

    To investigate whether physical exposure parameters such as the dose index (CTDI), dose length product (DLP), and size-specific dose estimate (SSDE) are predictive of DNA damage. In vitro, we scanned a phantom containing blood samples from five volunteers at CTDI 50, 100, and 150 mGy. One sample was not scanned. We also scanned samples in three different-size phantoms at CTDI 100 mGy. In vivo, we enrolled 45 patients and obtained blood samples before and after cardiac CT. The γ-H2AX foci were counted. In vitro, in the control and at CTDI 50, 100, and 150 mGy, the number of γ-H2AX was 0.94 ± 0.24 (standard error, SE), 1.28 ± 0.30, 1.91 ± 0.47, and 2.16 ± 0.20. At SSDE 180, 156, and 135 mGy, it was 2.41 ± 0.20, 1.91 ± 0.47, and 1.42 ± 0.20 foci/cell. The γ-H2AX foci were positively correlated with the radiation dose and negatively correlated with the body size. In vivo, the γ-H2AX foci were significantly increased after CT (from 1.21 ± 0.19 to 1.92 ± 0.22 foci/cell) and correlated with CTDI, DLP, and SSDE. DNA damage was induced by cardiac CT. There was a correlation between the physical exposure parameters and γ-H2AX. (orig.)

  4. Quantitative assessment of emphysema from whole lung CT scans: comparison with visual grading

    Science.gov (United States)

    Keller, Brad M.; Reeves, Anthony P.; Apanosovich, Tatiyana V.; Wang, Jianwei; Yankelevitz, David F.; Henschke, Claudia I.

    2009-02-01

    Emphysema is a disease of the lungs that destroys the alveolar air sacs and induces long-term respiratory dysfunction. CT scans allow for imaging of the anatomical basis of emphysema and for visual assessment by radiologists of the extent present in the lungs. Several measures have been introduced for the quantification of the extent of disease directly from CT data in order to add to the qualitative assessments made by radiologists. In this paper we compare emphysema index, mean lung density, histogram percentiles, and the fractal dimension to visual grade in order to evaluate the predictability of radiologist visual scoring of emphysema from low-dose CT scans through quantitative scores, in order to determine which measures can be useful as surrogates for visual assessment. All measures were computed over nine divisions of the lung field (whole lung, individual lungs, and upper/middle/lower thirds of each lung) for each of 148 low-dose, whole lung scans. In addition, a visual grade of each section was also given by an expert radiologist. One-way ANOVA and multinomial logistic regression were used to determine the ability of the measures to predict visual grade from quantitative score. We found that all measures were able to distinguish between normal and severe grades (p<0.01), and between mild/moderate and all other grades (p<0.05). However, no measure was able to distinguish between mild and moderate cases. Approximately 65% prediction accuracy was achieved from using quantitative score to predict visual grade, with 73% if mild and moderate cases are considered as a single class.

  5. MicroCT-based comparison between fluorescence-aided caries excavation and conventional excavation.

    Science.gov (United States)

    Lai, Guangyun; Kaisarly, Dalia; Xu, Xiaohui; Kunzelmann, Karl-Heinz

    2014-02-01

    To evaluate and compare the use of micro-computed tomography (microCT) to investigate the mineral concentration of the treated dentin surface after caries removal with fluorescence-aided caries excavation (FACE) and conventional excavation. 20 extracted human teeth with dentin caries were bisected through the lesion center into two halves which were distributed to a FACE and a conventional excavation group. Tungsten-carbide round burs were used for both groups. Each specimen was investigated with microCT after excavation. The obtained images of all the specimens were evaluated using Image J. Based on the grey values, the linear attenuation coefficients were calculated. Four resin-embedded solid hydroxyapatite phantoms with the gradually increased mineral concentration were used to obtain a calibration curve and equation. Finally, the mineral concentration values of the superficial dentin of each specimen after removal and sound dentin were calculated. The data were compared with the Student's t-test. The statistical results showed that the linear attenuation coefficient (LAC) of the treated surface was significantly lower (P excavation group was 2.98 +/- 0.19 cm(-1). The LAC of sound dentin was 3.89 +/- 0.10 cm(-1). By using the calibration equation, the calculated mineral concentration of the superficial dentin after caries removal were 0.68 +/- 0.14 g/cm3 in the FACE group and 1.05 +/- 0.08 g/cm3 in the conventional excavation group. The mineral concentration of sound dentin was 1.44 +/- 0.04 g/cm3. The mineral concentration of the superficial dentin after caries removal in the FACE group was about 47% of that of sound dentin, while the value in the conventional excavation group was approximately 73% of that of sound dentin. Under the conditions of this in vitro study, the results of the microCT evaluation may imply that FACE was more conservative than conventional excavation.

  6. CT findings of mature cystic teratoma with malignant transformation: comparison with mature cystic teratoma.

    Science.gov (United States)

    Park, Sung Bin; Cho, Kyoung-Sik; Kim, Jeong Kon

    2011-01-01

    To evaluate the imaging findings of mature cystic teratoma with malignant transformation (malignant teratoma) compared with the corresponding mature cystic teratoma (benign teratoma). This study enrolled 1325 patients with 12 malignant teratomas and 1313 benign teratomas. We compared the computed tomographic (CT) findings of eight malignant teratomas and 15 benign teratomas; both groups were matched in terms of tumor size (>9.9 cm) and patient age (>45 years). The CT images were retrospectively evaluated with focus on soft tissue components; size, border (regular or irregular), the presence or absence of nodular formation, enhancement, the angle formed between the soft tissue components and the inner wall of the cyst (acute or obtuse), and transmural growth as well as metastasis including lymphadenopathy and disseminated disease. Using the Fischer's Exact test, each evaluating parameter was compared between the two groups. Soft tissue components were observed in 75% (six of eight) of malignant teratomas and in 33% (five of fifteen) of benign teratomas; 100% (six of six) of soft component in malignant teratomas had a nodular formation and none of soft component in benign teratomas showed nodular formation; 83% (five of six) of soft component in malignant teratomas had enhancement as well as an obtuse angle between the soft tissue components and the inner wall of the cyst. None of soft component in benign teratomas showed enhancement and 20% (one of five) of soft component in benign teratomas had an obtuse angle; 33% (two of six) of soft component in malignant teratomas showed transmural growth, 13% (one of eight) of malignant teratoma showed lymphadenopathy, and 38% (three of eight) showed disseminated disease. None of benign teratomas showed transmural growth, lymphadenopathy, or disseminated disease. A statistically significant difference between patients with and without malignant transformation was seen in terms of nodular formation, obtuse angle, and

  7. Abdominal CT: comparison of adaptive statistical iterative and filtered back projection reconstruction techniques.

    Science.gov (United States)

    Singh, Sarabjeet; Kalra, Mannudeep K; Hsieh, Jiang; Licato, Paul E; Do, Synho; Pien, Homer H; Blake, Michael A

    2010-11-01

    To compare image quality and lesion conspicuity on abdominal computed tomographic (CT) images acquired with different x-ray tube current-time products (50-200 mAs) and reconstructed with adaptive statistical iterative reconstruction (ASIR) and filtered back projection (FBP) techniques. Twenty-two patients (mean age, 60.1 years ± 7.3 [standard deviation]; age range, 52.8-67.4 years; mean weight, 78.9 kg ± 18.3; 12 men, 10 women) gave informed consent for this prospective institutional review board-approved and HIPAA-compliant study, which involved the acquisition of four additional image series at multidetector CT. Images were acquired at different tube current-time products (200, 150, 100, and 50 mAs) and encompassed an abdominal lesion over a 10-cm scan length. Images were reconstructed separately with FBP and with three levels of ASIR-FBP blending. Two radiologists reviewed FBP and ASIR images for image quality in a blinded and randomized manner. Volume CT dose index (CTDI(vol)), dose-length product, patient weight, objective noise, and CT numbers were recorded. Data were analyzed by using analysis of variance and the Wilcoxon signed rank test. CTDI(vol) values were 16.8, 12.6, 8.4, and 4.2 mGy for 200, 150, 100, and 50 mAs, respectively (P 22 image series acquired at 4.2 mGy with 70% ASIR. Lesion conspicuity was significantly better at 4.2 mGy on ASIR than on FBP images (observed P < .044), and overall diagnostic confidence changed from unacceptable on FBP to acceptable on ASIR images. ASIR lowers noise and improves diagnostic confidence in and conspicuity of subtle abdominal lesions at 8.4 mGy when images are reconstructed with 30% ASIR blending and at 4.2 mGy in patients weighing 90 kg or less when images are reconstructed with 50% or 70% ASIR blending. © RSNA, 2010.

  8. Comparison of CT urography and intravenous urography in patients with hematuria

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Guen Young; Kang, Byung Chul; Hwang, Ji Young [Ewha Womans University College of Medicine, Seoul (Korea, Republic of)

    2006-12-15

    We wanted to compare CT urography (CTU) with using multi-detector row CT (MDCT) and intravenous urography (IVU) for diagnosing the causes of hematuria. From January 2003 to March 2004, IVU and CTU were obtained in 48 patients. We evaluated the causes of hematuria in 34 of 48 patients. The IVU images were obtained by the conventional method. The CTU images were routinely obtained before intravenous contrast injection, and at 2 and 5 minutes after intravenous contrast injection. In case of delayed excretion of contrast by the kidneys, the delayed CT scans were obtained at 120 minutes after contrast injection. All the CT images, including the axial and 3D coronal reformatted CTUs with using software as well as conventional IVU images, were reviewed by two radiologists working in consensus. We decided if urinary stone existed or not and we looked for the indirect signs such as hydronephrosis or delayed excretion, etc. We also observed if it was possible to determine the mass, ureteral stricture and enhancement of the ureteral wall, etc. We calculated sensitivity, specificity, positive predictive value and negative predictive value for each modality to diagnose urinary stone. We compared the detection rate according to the phases of CTU. We confirmed the presence of urinary tract stones in 27 of 34 patients who had undergone both IVU and CTU. We diagnosed ureteritis in 1, transitional cell carcinoma in 5 and acute pyelonephritis in 1 of the remaining 7 patients. The urinary stones were detected in fifteen patients on both IVU and CTU (15/27, 55.6%). We detected the urinary stones on CTU, but not IVU, in twelve patients (12/27, 44.5%). The sensitivity to detect the urinary stones was 100% (27/27) on CTU and 55.6% (12/27) on IVU respectively. The specificity was 100% (7/7) on IVU and CTU, respectively. The positive predictive value was 100% (15/15) on IVU and 100% (27/27) on CTU, respectively. The negative predictive value was 36.8% (7/19) on IVU and 100% (7/7) on CTU

  9. A comparison of x-ray detectors for mouse CT imaging

    Science.gov (United States)

    Goertzen, Andrew L.; Nagarkar, Vivek; Street, Robert A.; Paulus, Michael J.; Boone, John M.; Cherry, Simon R.

    2004-12-01

    There is significant interest in using computed tomography (CT) for in vivo imaging applications in mouse models of disease. Most commercially available mouse x-ray CT scanners utilize a charge-coupled device (CCD) detector coupled via fibre optic taper to a phosphor screen. However, there has been little research to determine if this is the optimum detector for the specific task of in vivo mouse imaging. To investigate this issue, we have evaluated four detectors, including an amorphous selenium (a-Se) detector, an amorphous silicon (a-Si) detector with a gadolinium oxysulphide (GOS) screen, a CCD with a 3:1 fibre taper and a GOS screen, and a CCD with a 2:1 fibre taper and both GOS and thallium-doped caesium iodide (CsI:Tl) screens. The detectors were evaluated by measuring the modulation transfer function (MTF), noise power spectrum (NPS), detective quantum efficiency (DQE), stability over multiple exposures, and noise in reconstructed CT images. The a-Se detector had the best MTF and the highest DQE (0.6 at 0 lp mm-1) but had the worst stability (45% reduction after 2000 exposure frames). The a-Si detector and the CCD with the 3:1 fibre, both of which used the GOS screen, had very similar performance with a DQE of approximately 0.30 at 0 lp mm-1. For the CCD with the 2:1 fibre, the CsI:Tl screen resulted in a nearly two-fold improvement in DQE over the GOS screen (0.4 versus 0.24 at 0 lp mm-1). The CCDs both had the best stability, with less than a 1% change in pixel values over multiple exposures. The pixel values of the a-Si detector increased 5% over multiple exposures due to the effects of image lag. Despite the higher DQE of the a-Se detector, the reconstructed CT images acquired with the a-Si detector had lower noise levels, likely due to the blurring effects from the phosphor screen.

  10. A comparison of x-ray detectors for mouse CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Goertzen, Andrew L [Department of Biomedical Engineering, University of California, Davis, Davis, CA (United States); Nagarkar, Vivek [Radiation Monitoring Devices Inc., Watertown, MA (United States); Street, Robert A [Palo Alto Research Center, Palo Alto, CA (United States); Paulus, Michael J [Imtek Inc., Knoxville, TN (United States); Boone, John M [Department of Biomedical Engineering, University of California, Davis, Davis, CA (United States); Cherry, Simon R [Department of Biomedical Engineering, University of California, Davis, Davis, CA (United States)

    2004-12-07

    There is significant interest in using computed tomography (CT) for in vivo imaging applications in mouse models of disease. Most commercially available mouse x-ray CT scanners utilize a charge-coupled device (CCD) detector coupled via fibre optic taper to a phosphor screen. However, there has been little research to determine if this is the optimum detector for the specific task of in vivo mouse imaging. To investigate this issue, we have evaluated four detectors, including an amorphous selenium (a-Se) detector, an amorphous silicon (a-Si) detector with a gadolinium oxysulphide (GOS) screen, a CCD with a 3:1 fibre taper and a GOS screen, and a CCD with a 2:1 fibre taper and both GOS and thallium-doped caesium iodide (CsI:Tl) screens. The detectors were evaluated by measuring the modulation transfer function (MTF), noise power spectrum (NPS), detective quantum efficiency (DQE), stability over multiple exposures, and noise in reconstructed CT images. The a-Se detector had the best MTF and the highest DQE (0.6 at 0 lp mm{sup -1}) but had the worst stability (45% reduction after 2000 exposure frames). The a-Si detector and the CCD with the 3:1 fibre, both of which used the GOS screen, had very similar performance with a DQE of approximately 0.30 at 0 lp mm{sup -1}. For the CCD with the 2:1 fibre, the CsI:Tl screen resulted in a nearly two-fold improvement in DQE over the GOS screen (0.4 versus 0.24 at 0 lp mm{sup -1}). The CCDs both had the best stability, with less than a 1% change in pixel values over multiple exposures. The pixel values of the a-Si detector increased 5% over multiple exposures due to the effects of image lag. Despite the higher DQE of the a-Se detector, the reconstructed CT images acquired with the a-Si detector had lower noise levels, likely due to the blurring effects from the phosphor screen.

  11. Comparison of image quality in head CT studies with different dose-reduction strategies

    DEFF Research Database (Denmark)

    Johansen, Jeppe; Nielsen, Rikke; Fink-Jensen, Vibeke

    account to a considerable radiation dose as many patients undergo repeated studies. Therefore, various dose-reduction strategies are applied such as automated tube current and voltage modulation and recently different iterative reconstruction algorithms. However, the trade-off of all dose......-reduction maneuvers is reduction of image quality due to image noise or artifacts. The aim of our study was therefore to find the best diagnostic images with lowest possible dose. We present results of dose- and image quality optimizing strategies of brain CT examinations at our institution. We compare sequential...

  12. Comparison of ultrasound with plain radiography and CT for the detection of mediastinal lymphadenopathy in children with tuberculosis

    Energy Technology Data Exchange (ETDEWEB)

    Bosch-Marcet, Joaquim; Zuasnabar-Cotro, Amalia; Catala-Puigbo, Margarita; Simon-Riazuelo, Jose L. [Hospital General de Granollers, Department of Paediatrics, Avda. Francesc Ribas s/n, Barcelona (Spain); Serres-Creixams, Xavier [Hospital General de Granollers, Department of Diagnostic Imaging, Barcelona (Spain); Codina-Puig, Xavier [Hospital General de Granollers, Emergency Department, Barcelona (Spain)

    2004-11-01

    Lymphadenopathy, with or without parenchymal abnormality, is the radiological hallmark of primary tuberculosis (TB) in children. However, lymph node enlargement may pass undetected on plain chest radiographs. Ultrasonography provides complementary information to that obtained by radiographs. To assess the clinical value of US for the detection of mediastinal lymphadenopathy in children with a positive intradermal tuberculin test. Thirty-two children with a mean age of 6 years and a positive Mantoux test underwent chest radiography (frontal and lateral) and US (suprasternal and left parasternal access routes). Chest CT was performed at the discretion of the attending physician in six cases. Eleven children had clinical symptoms and 90% a recent contact with a person with active TB. In 90.5% of children with chest radiographic images compatible with TB, coincident findings in the mediastinal US study were found. By comparison, 66.7% of those with normal chest radiography had evidence of mediastinal lymphadenopathy on the US scan. In all cases but one, US and CT findings agreed. Mediastinal US is useful for the detection of enlarged lymph nodes in children with a positive tuberculin reaction and normal chest radiography. (orig.)

  13. Diagnostic performance of CT and MRI on the detection of symptomatic intracranial dural arteriovenous fistula: a meta-analysis with indirect comparison

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yen-Heng [National Taiwan University, Institute of Epidemiology and Preventive Medicine, Taipei (China); National Taiwan University Hospital in Taipei and Yuan-Lin Branch, Department of Medical Imaging and Radiology, Hospital and Medical College, Taipei (China); Lin, Hsien-Ho [National Taiwan University, Institute of Epidemiology and Preventive Medicine, Taipei (China); Liu, Hon-Man; Lee, Chung-Wei; Chen, Ya-Fang [National Taiwan University Hospital in Taipei and Yuan-Lin Branch, Department of Medical Imaging and Radiology, Hospital and Medical College, Taipei (China)

    2016-08-15

    This study aims to review the diagnostic performance of computed tomography (CT) and magnetic resonance imaging (MRI) in symptomatic dural arteriovenous fistula (DAVF). EMBASE, PubMed, and Cochrane Library were searched until April 2015 for studies which compared CT, MRI, or both with angiography for the detection of DAVF. The diagnostic performances of MRI and CT were indirectly compared using modality as a covariate in the analysis. Thirteen studies met our inclusion criteria. MRI had a sensitivity of 0.90 (95 % confidence interval (CI) = 0.83-0.94) and specificity of 0.94 (95 % CI = 0.90-0.96). CT had a sensitivity of 0.80 (95 % CI = 0.62-0.90) and specificity of 0.87 (95 % CI = 0.74-0.94). MRI showed better diagnostic performance than CT (p = 0.02). Contrast medium use and time-resolved MR angiography did not improve MRI diagnostic performance (p = 0.31 and 0.44, respectively). Both CT and MRI had good diagnostic performance. MRI was better than CT on the detection of symptomatic intracranial dural arteriovenous fistula in the indirect comparison. (orig.)

  14. Comparison between {sup 18}F-FDG PET/CT and EMG Mapping for Identifying Dystonic Superficial Muscles in Primary Cervical Dystonia: Preliminary Results

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Su Jin [Seoul National University School, Seoul (Korea, Republic of); Choi, Joon Young; Sung, Duk Hyun; Park, Kwang Hong; Lee, Ji Young; Cho, Sook Kyung; Yu, Jang; Lee, Kyung Han; Kim, Byung Tae [Sungkyunkawn University School of Medicine, Seoul (Korea, Republic of)

    2010-04-15

    This study was conducted to compare {sup 18}F-FDG PET/CT and electromyography (EMG) mapping in patients with primary cervical dystonia (PCD) to find dystonic superficial cervical muscles. Ten consecutive patients with PCD (M:F=5:5, age 44{+-}13 years) whose dystonic posture was not relieved with conventional muscle relaxant therapy were included. Target cervical muscles for the comparison between {sup 18}F-FDG PET/CT and EMG mapping were four representative superficial bilateral cervical muscles: splenius capitis muscle, sternocleidomstoid muscle, upper trapeziums muscle, and levitator scapulae muscle. The diagnostic efficacy was compared between {sup 18}F-FDG PET/CT and EMG mapping using physical exam and measurement of rotation angle as the gold standard. Among 80 muscles evaluated, there were 21 (26%) dystonic superficial cervical muscles assessed with physical exam and motion analysis. The sensitivity, specificity, and accuracy for localizing dystonic muscles were 76, 92, and 88% for {sup 18}F-FDG PET/CT, and 95, 66, and 74% for EMG mapping, respectively. The sensitivity of EMG mapping was significantly higher than that of {sup 18}F-FDG PET/CT. In contrast, {sup 18}F-FDG PET/CT is more specific and accurate than EMG mapping for finding superficial dystonic cervical muscles. The high sensitivity of EMG mapping suggests that {sup 18}F-FDG PET/CT and EMG mapping are complementary for finding dystonic superficial cervical muscles.

  15. Intrinsic carpal ligaments on MR and multidetector CT arthrography: comparison of axial and axial oblique planes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ryan K.L.; Griffith, James F.; Ng, Alex W.H.; Law, Eric K.C. [The Chinese University of Hong Kong, Department of Imaging and Interventional Radiology, Prince Of Wales Hospital, Hong Kong (China); Tse, W.L.; Wong, Clara W.Y.; Ho, P.C. [The Chinese University of Hong Kong, Department of Orthopedics and Traumatology, Prince Of Wales Hospital, Hong Kong (China)

    2017-03-15

    To compare axial and oblique axial planes on MR arthrography (MRA) and multidetector CT arthrography (CTA) to evaluate dorsal and volar parts of scapholunate (SLIL) and lunotriquetral interosseous (LTIL) ligaments. Nine cadaveric wrists of five male subjects were studied. The visibility of dorsal and volar parts of the SLIL and LTIL was graded semi-quantitatively (good, intermediate, poor) on MRA and CTA. The presence of a ligament tear was determined on arthrosocopy and sensitivity, specificity and accuracy of tear detection were calculated. Oblique axial imaging was particularly useful for delineating dorsal and volar parts of the LTIL on MRA with overall 'good' visibility increased from 11 % to 78 %. The accuracy of MRA and CTA in revealing SLIL and LTIL tear was higher using the oblique axial plane. The overall accuracy for detecting SLIL tear on CTA improved from 94 % to 100 % and from 89 % to 94 % on MRA; the overall accuracy of detecting LTIL tear on CTA improved from 89 % to 100 % and from 72 % to 89 % on MRA Oblique axial imaging during CT and MR arthrography improves detection of tears in the dorsal and volar parts of both SLIL and LTIL. (orig.)

  16. Multidetector CT imaging of pleura: comparison of two contrast infusion protocols.

    Science.gov (United States)

    Raj, V; Kirke, R; Bankart, M J; Entwisle, J J

    2011-09-01

    Imaging of the pleura by multidetector CT (MDCT) can be challenging. There is no clear evidence or guidelines on contrast infusion parameters for imaging pleura. We compared two contrast protocols for assessing pleural pathology on MDCT. This was a prospective study in which consecutive patients with MDCT for suspected pleural disease on chest radiograph were randomised into two groups. The first group received 150 ml of intravenous contrast at a rate of 2.5 ml s(-1) and the second group received 100 ml at 2 ml s(-1). Images were acquired after a 60 s delay. Hounsfield units of the pleura, thoracic aorta, main pulmonary artery, portal vein and superior mesenteric artery were measured and analysed by two independent readers. 40 patients (20 in each group) who had pleural enhancement on MDCT were included for final analysis. The mean pleural enhancement value was 83 HU (Group A) vs 59 HU (Group B) (p = 0.0004). The mean aortic enhancement was 241 HU (A) vs 141 HU (B) (ppleura and major vessels was significantly higher in the group receiving more contrast at a greater infusion rate. This technique of a single scan through the entire pleural surface with a delayed acquisition is promising. When pleural disease is suspected, contrast infusion protocols should be modified to achieve the best results and clinicians should be encouraged to specifically request a "pleural CT".

  17. Sonographic diagnosis of nephrolithiasis - a comparison of US, IVP and CT in 310 patients

    Energy Technology Data Exchange (ETDEWEB)

    Becker-Gaab, C.; Perouansky, M.; Zrenner, M.; Zur Nieden, J.

    1986-09-01

    The authors compared the value of sonography with I.V. urography and CT in the diagnosis of nephrolithiasis, employing a retrospective study conducted on 310 patients. False positive and false negative sonographic findings were analysed in retrospect and the differential diagnosis discussed. Sonography proved of equal value to I.V. urography, 90% correct diagnoses were made via sonography; its sensitivity was 89%, its specificity 91%. 29% of the sonographically correctly diagnosed kidney stones had been detected by chance. The smallest sonographically identified stone was 3 mm, whereas the biggest stone that had been missed out was 7 mm. Sonography is definitely superior to I.V. urography in the detection of nephrocalcinosis and of roentgen-negative stones. Sonographically questinable parenchymal calcifications without shadowing should be investigated further by CT in case of clinical significance, even if the plain film is negative. The number of false positive findings in sonography can thus be reduced. Sonographic differentiation between central parenchymal calcification and stone formation is difficult in rare cases only. If required, additional information can be obtained via I.V. urography. The authors recommend sonography as the method of choice for suspected nephrolithiasis before I.V. urography is performed.

  18. Head-to-head comparison between {sup 18}F-FDOPA PET/CT and MR/CT angiography in clinically recurrent head and neck paragangliomas

    Energy Technology Data Exchange (ETDEWEB)

    Heimburger, Celine; Hubele, Fabrice; Namer, Izzie Jacques [University Hospitals of Strasbourg, Department of Biophysics and Nuclear Medicine, Strasbourg (France); CNRS/University of Strasbourg, ICube, UMR 7357, Strasbourg (France); University of Strasbourg, FMTS, Faculty of Medicine, Strasbourg (France); Veillon, Francis; Riehm, Sophie; Cavalcanti, Marcela [University Hospitals of Strasbourg, Department of Radiology, Strasbourg (France); Taieb, David [Aix-Marseille University, Department of Nuclear Medicine, La Timone University Hospital, Marseille (France); Aix-Marseille University, European Center for Research in Medical Imaging, Marseille (France); Institut Paoli-Calmettes, Inserm UMR1068 Marseille Cancerology Research Center, Marseille (France); Goichot, Bernard; Chabrier, Gerard [University Hospitals of Strasbourg, Department of Internal Medicine, Strasbourg (France); Petit-Thomas, Julie; Charpiot, Anne [University Hospitals of Strasbourg, Department of Otolaryngology and Maxillofacial Surgery, Strasbourg (France); Averous, Gerlinde [University Hospitals of Strasbourg, Department of Pathology, Strasbourg (France); Imperiale, Alessio [University Hospitals of Strasbourg, Department of Biophysics and Nuclear Medicine, Strasbourg (France); CNRS/University of Strasbourg, ICube, UMR 7357, Strasbourg (France); University of Strasbourg, FMTS, Faculty of Medicine, Strasbourg (France); Hautepierre University Hospital, Biophysics and Nuclear Medicine, Strasbourg Cedex (France)

    2017-06-15

    Head and neck paragangliomas (HNPGLs) can relapse after primary treatment. Optimal imaging protocols have not yet been established for posttreatment evaluation. The aim of the present study was to assess the diagnostic value of {sup 18}F-FDOPA PET/CT and MR/CT angiography (MRA/CTA) in HNPGL patients with clinical relapse during their follow-up. Sixteen consecutive patients presenting with local pain, tinnitus, dysphagia, hoarse voice, cranial nerve involvement, deafness, or retrotympanic mass appearing during follow-up after the initial treatment of HNPGLs were retrospectively evaluated. Patients underwent both {sup 18}F-FDOPA PET/CT and MRA (15 patents) or CTA (1 patent). Both methods were first assessed under blinded conditions and afterwards correlated. Head and neck imaging abnormalities without histological confirmation were considered true-positive results based on a consensus between radiologists and nuclear physicians and on further {sup 18}F-FDOPA PET/CT and/or MRA. {sup 18}F-FDOPA PET/CT and MRA/CTA were concordant in 14 patients and in disagreement in 2 patients. {sup 18}F-FDOPA PET/CT and MRA/CTA identified, respectively, 12 and 10 presumed recurrent HNPGLs in 12 patients. The two lesions diagnosed by PET/CT only were confirmed during follow-up by otoscopic examination and MRA performed 29 and 17 months later. {sup 18}F-FDOPA PET/CT images were only slightly influenced by the posttreatment sequelae, showing a better interobserver reproducibility than MRA/CTA. Finally, in 2 of the 16 studied patients, {sup 18}F-FDOPA PET/CT detected two additional synchronous primary HNPGLs. {sup 18}F-FDOPA PET/CT is highly sensitive in posttreatment evaluation of patients with HNPGLs, and also offers better interobserver reproducibility than MRA/CTA and whole-body examination. We therefore suggest that {sup 18}F-FDOPA PET/CT is performed as the first diagnostic imaging modality in symptomatic patients with suspicion of HNPGL relapse after primary treatment when {sup 68

  19. Detection of underlying malignancy in patients with paraneoplastic neurological syndromes: comparison of {sup 18}F-FDG PET/CT and contrast-enhanced CT

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, N.; Schmid-Tannwald, C.; Meinel, F.G.; Reiser, M.F.; Rist, C. [Ludwig-Maximilians-University Hospital Munich, Institute for Clinical Radiology, Munich (Germany); Rominger, A. [Ludwig-Maximilians-University Hospital Munich, Department of Nuclear Medicine, Munich (Germany); Schmidt, C. [Ludwig-Maximilians-University Hospital Munich, Department of Neurology, Munich (Germany); Morelli, J.N. [Texas A and M Health Sciences Center, Department of Radiology, Temple, TX (United States)

    2013-07-15

    To determine the value of combined {sup 18}F-FDG PET/CT with diagnostic contrast-enhanced CT (CECT) in detecting primary malignancies and metastases in patients with paraneoplastic neurological syndromes (PNS) and to compare this with CECT alone. PET/CT scans from 66 patients with PNS were retrospectively evaluated. Two blinded readers initially reviewed the CECT portion of each PET/CT scan. In a second session 3 months later, the readers analysed the combined PET/CT scans. Findings on each study were assessed using a four-point-scale (1 normal/benign; 2 inconclusive, further diagnostic work-up may be necessary; 3 malignant; 4 inflammatory). Sensitivity and specificity for malignant findings were calculated for PET/CT and CECT. Interreader agreement was determined by calculating Cohen's kappa. Pooled data from clinical follow-up (including histopathology and follow-up imaging, median follow-up 20.0 months) served as the reference gold standard. Both readers classified 12 findings in ten patients (15 %) as malignant on the PET/CT scans (two patients had two primary tumours). One such imaging finding (suspected thymic cancer) was false-positive (i.e. benign histology). The most common tumours were bronchial carcinoma (n = 3), lymph node metastases of gynaecological tumours (n = 3) and tonsillar carcinoma (n = 2). Three of 12 findings (25 %) were not detected by CECT alone (cervical carcinoma, lymph node metastasis and tonsillar carcinoma). In a per-patient analysis, sensitivity and specificity for malignant findings were 100 % and 90 % for PET/CT and 78 % and 88 % for CECT. In 24 % (reader 1) and 21 % (reader 2) of the patients, the PET/CT findings were inconclusive. Of these findings, 57 % (reader 1) and 56 % (reader 2) were only diagnosed with PET (e.g. focal FDG uptake of the thyroid, gastrointestinal tract and ovaries). On follow-up, none of these findings corresponded to malignancy. Overall agreement between the two readers was excellent with a Cohen

  20. Poster - Thurs Eve-19: IGRT QA for helical tomotherapy.

    Science.gov (United States)

    Parker, W; Evans, M; Ruo, R; Patrocinio, H

    2008-07-01

    Helical tomotherapy (HT) with daily imaging using mega-voltage computed tomography for 3D image guided radiotherapy (IGRT). We present two techniques developed in our department to verify the integrity of the HT IGRT process. A phantom was constructed of two equally sized (5×10×10cm3 ) polystyrene blocks stacked on top of each other, each piece having a hole capable of receiving a small volume ionization chamber. A piece of Radiochromic film fits neatly in between the blocks. The phantom was CT scanned and the CT slices were transferred to the HT treatment planning system (TPS). The first procedure is used daily to test the image registration aspects of the IGRT process, and involves setting the phantom on the tomotherapy treatment unit table in an arbitrary position, imaging it, and performing image registration to determine what displacements are necessary to return the phantom to the planned position. A variation of this test is to place the phantom at a position incurring known displacements and ensuring the registration recognizes the shifts. The second procedure verifies the entire IGRT procedure, and includes the first procedure and the delivery of a treatment plan. An inverse plan is created to deliver simultaneously 2 and 3 Gy to 2 pre-defined targets. The treatment plan can be setup as a QA plan in the TPS software, allowing for a detailed comparison of ion chamber measurements and film dosimetry to the planned dose distribution. We have found that these QA procedures adequately test the IGRT capabilities of our HT unit. © 2008 American Association of Physicists in Medicine.

  1. Comparison of FDG-PET/CT and contrast-enhanced CT for monitoring therapy response in patients with metastatic breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Riedl, Christopher C.; Ulaner, Gary A.; Jochelson, Maxine S.; Weber, Wolfgang A. [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Weill Cornell Medical College, Department of Radiology, New York, NY (United States); Pinker, Katja [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria); Ong, Leonard T. [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Baltzer, Pascal [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria); McArthur, Heather L. [Cedars-Sinai Medical Center, Department of Medicine, Breast Oncology, Los Angeles, CA (United States); Goenen, Mithat [Memorial Sloan Kettering Cancer Center, Department of Epidemiology and Biostatistics, New York, NY (United States); Dickler, Maura [Memorial Sloan Kettering Cancer Center, Department of Medicine, New York, NY (United States)

    2017-08-15

    The aim of this study was to compare fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) and contrast-enhanced computed tomography (CE-CT) for the prediction of progression-free survival (PFS) and disease-specific survival (DSS) in patients with stage IV breast cancer undergoing systemic therapy. Sixty-five patients with metastatic breast cancer treated with first- or second-line systemic therapy in prospective clinical trials were included. Response to treatment was evaluated by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 for CE-CT and by PET Response Criteria in Solid Tumors (PERCIST), respectively. All responders by RECIST (n = 22) were also responders by PERCIST, but 40% (17/43) of non-responders by RECIST were responders by PERCIST. Responses according to RECIST and PERCIST both correlated with PFS, but PERCIST showed a significantly higher predictive accuracy (concordance index for PFS: 0.70 vs. 0.60). One-year PFS for responders vs. non-responders by RECIST was 59% vs. 27%, compared to 63% vs. 0% by PERCIST. Four-year DSS of responders and non-responders by RECIST was 50% and 38%, respectively (p = 0.2, concordance index: 0.55) as compared to 58% vs. 18% for PERCIST (p < 0.001, concordance index: 0.65). Response on PET/CT was also a significantly better predictor for DSS than disease control on CE-CT. In patients with metastatic breast cancer, tumor response on PET/CT appears to be a superior predictor of PFS and DSS than response on CE-CT. Monitoring tumor response by PET/CT may increase the power of clinical trials using tumor response as an endpoint, and may improve patient management in clinical routine. (orig.)

  2. CT findings of minimally invasive adenocarcinoma (MIA) of the lung and comparison of solid portion measurement methods at CT in 52 patients

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Min; Lee, Kyung Hee; Park, Chang Min [Seoul National University Medical Research Center, Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Jongno-gu, Seoul (Korea, Republic of); Goo, Jin Mo [Seoul National University Medical Research Center, Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Jongno-gu, Seoul (Korea, Republic of); Seoul National University College of Medicine, Cancer Research Institute, Seoul (Korea, Republic of); Chung, Doo Hyun; Koh, Jaemoon [Seoul National University College of Medicine, Department of Pathology, Seoul (Korea, Republic of)

    2015-08-15

    We aimed to retrospectively investigate CT findings of minimally invasive adenocarcinoma (MIA) and to determine the appropriate method for measurement of solid portions in MIAs at CT. From May 2012 to April 2014, 55 pulmonary nodules in 52 patients were pathologically confirmed as MIAs and were included in this study. CT findings of MIAs and measurements of solid portions at CT were evaluated by two independent radiologists. Mean size of MIAs was 10.5 mm ± 4.8 (range, 4-28 mm). Fifty-two MIAs manifested as 28 pure ground glass nodules (GGNs) (53.8 % %), 22 part-solid GGNs (42.3 % %), and 2 two solid nodules (3.8 % %) at CT. Lobulated border, bubble lucency, and pleural retraction were frequently found in both observers (26.9-42.3 % %). Differences according to window settings between solid portion size and invasive component size were not significantly different in both observers (p > 0.05). As for interobserver agreement, 95 % CIs for solid portion size in the mediastinal window setting (-2.2 to 3.4; mean, 0.6) were slightly narrower than those in the lung window setting (-2.6 to 3.1; mean, 0.3). Nearly all MIAs appear as pure and part-solid GGNs. Mediastinal and lung window settings can be applied for measurement of solid portions at CT without a significant difference. (orig.)

  3. Packing of Helices: Is Chirality the Highest Crystallographic Symmetry?

    Directory of Open Access Journals (Sweden)

    Romain Gautier

    2016-08-01

    Full Text Available Chiral structures resulting from the packing of helices are common in biological and synthetic materials. Herein, we analyze the noncentrosymmetry (NCS in such systems using crystallographic considerations. A comparison of the chiral structures built from helices shows that the chirality can be expected for specific building units such as 31/32 or 61/65 helices which, in hexagonal arrangement, will more likely lead to a chiral resolution. In these two systems, we show that the highest crystallographic symmetry (i.e., the symmetry which can describe the crystal structure from the smallest assymetric unit is chiral. As an illustration, we present the synthesis of two materials ([Zn(2,2’-bpy3](NbF62 and [Zn(2,2’-bpy3](TaF62 in which the 3n helices pack into a chiral structure.

  4. Magnetic helicity and higher helicity invariants as constraints for dynamo action

    Science.gov (United States)

    Sokoloff, Dmitry; Akhmetyev, Peter; Illarionov, Egor

    2018-01-01

    We consider classical magnetic helicity (a Gauss invariant of magnetic lines) and higher helicity invariants as nonlinear constraints for dynamo action. We argue that the Gauss invariant has several properties absent from higher helicity invariants which prevents use of the latter to constrain dynamo action. We consider other helicities (hydrodynamic helicity and cross helicity) in the context of the dynamo problem.

  5. Bowel sparing in pediatric cranio-spinal radiotherapy: a comparison of combined electron and photon and helical TomoTherapy techniques to a standard photon method

    Energy Technology Data Exchange (ETDEWEB)

    Harron, Elizabeth, E-mail: elizabeth.harron@nuh.nhs.uk [Regional Medical Physics Department, Freeman Hospital, Freeman Road, Newcastle upon Tyne (United Kingdom); Lewis, Joanne [Northern Centre for Cancer Care, Freeman Hospital, Freeman Road, Newcastle upon Tyne (United Kingdom)

    2012-07-01

    The aim of this study was to compare the dose to organs at risk (OARs) from different craniospinal radiotherapy treatment approaches available at the Northern Centre for Cancer Care (NCCC), with a particular emphasis on sparing the bowel. Method: Treatment plans were produced for a pediatric medulloblastoma patient with inflammatory bowel disease using 3D conformal 6-MV photons (3DCP), combined 3D 6-MV photons and 18-MeV electrons (3DPE), and helical photon TomoTherapy (HT). The 3DPE plan was a modification of the standard 3DCP technique, using electrons to treat the spine inferior to the level of the diaphragm. The plans were compared in terms of the dose-volume data to OARs and the nontumor integral dose. Results: The 3DPE plan was found to give the lowest dose to the bowel and the lowest nontumor integral dose of the 3 techniques. However, the coverage of the spine planning target volume (PTV) was least homogeneous using this technique, with only 74.6% of the PTV covered by 95% of the prescribed dose. HT was able to achieve the best coverage of the PTVs (99.0% of the whole-brain PTV and 93.1% of the spine PTV received 95% of the prescribed dose), but delivered a significantly higher integral dose. HT was able to spare the heart, thyroid, and eyes better than the linac-based techniques, but other OARs received a higher dose. Conclusions: Use of electrons was the best method for reducing the dose to the bowel and the integral dose, at the expense of compromised spine PTV coverage. For some patients, HT may be a viable method of improving dose homogeneity and reducing selected OAR doses.

  6. Temporal bone CT findings of tuberculous otitis media : comparison with chronic otitis media

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Jeong A; Rho, Myung Ho; Kim, Young Min; Lee, Ho Seung; Choi, Pil Yeob; Seong, Young Soon; Kwon, Jae Soo; Lee, Sang Wook [Masan Samsung Hospital, Sungkyunkwan Univ. College of Medicine, Seoul (Korea, Republic of); Jung, Keon Sik [Pohang Sunrin Hospital, Pohang (Korea, Republic of)

    1999-06-01

    To compare the differential findings of tuberculous otitis media(TOM) with those of chronic sup purative otitis media with or without cholesteatoma, as seen on high resolution temporal bone CT. We retrospectively reviewed 14 cases of TOM, 30 cases of chronic suppurative otitis media(CSOM), and 30 cases of chronic otitis media with cholesteatoma(Chole). All had been pathologically confirmed. We evaluated the preservation of mastoid cells without sclerotic change, the location and extension of soft tissue to the external auditary canal, and erosion of ossicles, the tegmen tympani, scutum, bony labyrinth, facial nerve canal and sigmoid sinus, and the presence of intracranial complications. Soft tissue in the mastoid antrum was seen in all cases of TOM(100%), 29 cases of CSOM(96.7%), and 26 cases of Chole(86.7%). In contrast, the soft tissue in the entire middle ear cavity was noted in 13 cases of TOM(92.8%), 7 cases of CSOM(23.3%), and 12 cases of Chole(40%). Soft tissue extended to the superior aspect of the external auditory canal in 4 cases of TOM (28.6%) and 5 cases of Chole (16.7%). Mastoid air cells were seen in 9 cases of TOM (64.3%), 4 cases of CSOM (13.3%), and 3 cases of Chole(10%). Ossicular erosion was noted in 6 cases of TOM (42.9%), 12 cases of CSOM (40%), and 26 cases of Chole(86.7%), while in one case of TOM (7.1%), 5 cases of CSOM (16.7%), and 15 cases of Chole(50%) there was erosion of the scutum. In one case of TOM, follow-up CT study after 9 months of antituberculous medication without surgery revealed complete clearing of previously noted soft tissue in the middle ear cavity. Specific CT findings of TOM were not seen, but if there were findings of soft tissue in the entire middle ear cavity, soft tissue extension to the external auditory canal, preservation of mastoid air cells without sclerotic change, and intact scutum, TOM may be differentiated from other chronic otitis media.

  7. Comparison of measured and estimated maximum skin doses during CT fluoroscopy lung biopsies

    Energy Technology Data Exchange (ETDEWEB)

    Zanca, F., E-mail: Federica.Zanca@med.kuleuven.be [Department of Radiology, Leuven University Center of Medical Physics in Radiology, UZ Leuven, Herestraat 49, 3000 Leuven, Belgium and Imaging and Pathology Department, UZ Leuven, Herestraat 49, Box 7003 3000 Leuven (Belgium); Jacobs, A. [Department of Radiology, Leuven University Center of Medical Physics in Radiology, UZ Leuven, Herestraat 49, 3000 Leuven (Belgium); Crijns, W. [Department of Radiotherapy, UZ Leuven, Herestraat 49, 3000 Leuven (Belgium); De Wever, W. [Imaging and Pathology Department, UZ Leuven, Herestraat 49, Box 7003 3000 Leuven, Belgium and Department of Radiology, UZ Leuven, Herestraat 49, 3000 Leuven (Belgium)

    2014-07-15

    Purpose: To measure patient-specific maximum skin dose (MSD) associated with CT fluoroscopy (CTF) lung biopsies and to compare measured MSD with the MSD estimated from phantom measurements, as well as with the CTDIvol of patient examinations. Methods: Data from 50 patients with lung lesions who underwent a CT fluoroscopy-guided biopsy were collected. The CT protocol consisted of a low-kilovoltage (80 kV) protocol used in combination with an algorithm for dose reduction to the radiology staff during the interventional procedure, HandCare (HC). MSD was assessed during each intervention using EBT2 gafchromic films positioned on patient skin. Lesion size, position, total fluoroscopy time, and patient-effective diameter were registered for each patient. Dose rates were also estimated at the surface of a normal-size anthropomorphic thorax phantom using a 10 cm pencil ionization chamber placed at every 30°, for a full rotation, with and without HC. Measured MSD was compared with MSD values estimated from the phantom measurements and with the cumulative CTDIvol of the procedure. Results: The median measured MSD was 141 mGy (range 38–410 mGy) while the median cumulative CTDIvol was 72 mGy (range 24–262 mGy). The ratio between the MSD estimated from phantom measurements and the measured MSD was 0.87 (range 0.12–4.1) on average. In 72% of cases the estimated MSD underestimated the measured MSD, while in 28% of the cases it overestimated it. The same trend was observed for the ratio of cumulative CTDIvol and measured MSD. No trend was observed as a function of patient size. Conclusions: On average, estimated MSD from dose rate measurements on phantom as well as from CTDIvol of patient examinations underestimates the measured value of MSD. This can be attributed to deviations of the patient's body habitus from the standard phantom size and to patient positioning in the gantry during the procedure.

  8. Predisposing factors of pneumothorax in percutaneous transthoracic fine needle aspiration biopsy: comparison between CT emphysema score and pulmonary function test

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Ho; Park, Kyung Joo; Park, Dong Won; Jung, Kyung Il; Suh, Jung Ho [Ajou Univ. College of Medicine, Seoul (Korea, Republic of)

    1997-11-01

    To compare the CT emphysema score with various factors of pulmonary function test by simple spirometry and to use the result as a predictor of pneumothorax in percutaneous transthoracic fine needle aspiration biopsy. The CT scans of 106 patients who had undergone percutaneous transthoracic fine needle aspiration biopsy of lung lesions within the previous 18 months were retrospectively reviewed. In 75 of these 106 cases, the results of the pulmonary function test were also reviewed. On plain chest radiography, pneumothorax was noted in 20 cases (19%). Emphysema was blindly evaluated. We divided each lung into four segments and determined the severity and involved volume of emphysema, as seen on CT. Severity was classified as one of four grades, as follow : absence of emphysema=0 ; low attenuation area of less than 5mm=1 ; low attenuation area of more than 5mm, and vascular pruning with normal lung intervening=2 ; and diffuse low attenuation without intervening normal lung, and larger confluent low attenuation with vascular pruning and distortion of branching pattern occupying all or almost all the involved parenchyma=3. The involved area was also classified as one of four grades : less than 25%=1 ; 25 - 49%=2 ; 51 - 74%=3 ; and more than 75%=4. The CT emphysema score was defined as the average of the grade of severity multiplied by the grade of involved area. Pulmonary function tests, consisting of simple spirometry and a pulmonologist's interpretation, were evaluated. We also evaluated depth and size of lesion as known predisposing factors in postbioptic pneumothorax. Statistical analysis was performed using the chi-square test, Wilcoxon ranks sum W test and the student t test. A comparison between the two groups of occurrence(with or without pneumothorax) showed the emphysema scores to be 1.69{+-}2.0 and 1.11{+-}2.9, respectively ; there was thus no significant difference between the two groups (z= - 0.048, p>0.10). Nor were differences revealed by the

  9. Diagnostic accuracy of {sup 11}C-choline PET/CT in comparison with CT and/or MRI in patients with hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Lopci, Egesta [Nuclear Medicine Department, Humanitas Clinical and Research Center, Rozzano, MI (Italy); Torzilli, Guido; Donadon, Matteo; Palmisano, Angela [Hepatobiliary Surgery, Humanitas Clinical and Research Center, Rozzano, MI (Italy); Poretti, Dario; Lanza, Ezio; Pedicini, Vittorio [Radiology Unit, Humanitas Clinical and Research Center, Rozzano, MI (Italy); Neto, Lauro J.S. de; Sabongi, Juliano Guerra [Medicina Nuclear, Centro Medico Imagem, Sorocaba (Brazil); Rimassa, Lorenza; Personeni, Nicola [Medical Oncology and Hematology Unit, Humanitas Clinical and Research Center, Rozzano, MI (Italy); Ceriani, Roberto [Hepatology Unit, Humanitas Clinical and Research Center, Rozzano, MI (Italy); Comito, Tiziana; Scorsetti, Marta [Radiosurgery and Radiotherapy, Humanitas Clinical and Research Center, Rozzano, MI (Italy); Chiti, Arturo [Nuclear Medicine Department, Humanitas Clinical and Research Center, Rozzano, MI (Italy); Humanitas University, Chair of Diagnostic Imaging, Rozzano, MI (Italy)

    2015-08-15

    In recent decades, the use of radiopharmaceuticals in the assessment of hepatocellular carcinoma (HCC) has become established, and new findings indicate that radiolabelled choline has considerable potential in this setting. Therefore, in this study we aimed to assess the diagnostic role of {sup 11}C-choline positron emission tomography (PET)/CT, compared with conventional imaging with CT/MRI, in patients with HCC. The study population comprised 45 patients (male to female ratio = 37:8, median age 70.5 years) referred to our institution owing to HCC: 27 at initial diagnosis and 18 for restaging after recurrence. In all cases we performed whole-body {sup 11}C-choline PET/CT and compared its findings with contrast-enhanced CT (n = 35) or MRI (n = 29) or both (n = 15) for a total of 50 paired scans. The reference standard was either histological proof (21 patients) or a multidisciplinary consensus. Diagnostic accuracy was then determined in a scan-based (SBA) and a lesion-based analysis (LBA). On SBA the sensitivity and specificity for PET were 88 and 90 %, respectively, whereas for CT/MRI they were 90 and 73 %, respectively (p > 0.05). On LBA the overall sensitivity and specificity were 78 and 86 %, respectively, for PET vs 65 and 55 % for CT/MRI. Overall we investigated 168 disease sites, of which 100 were in the liver and 68 were extrahepatic. When considering only liver lesions, {sup 11}C-choline PET and CT/MRI showed an accuracy of 66 and 85 %, respectively, while for extrahepatic lesions PET showed an accuracy of 99 %, while the accuracy of CT/MRI was 32 %. In both cases, there was a statistically significant difference in accuracy between the two modalities (p < 0.01). Combination of the PET results with those of CT/MRI resulted in the highest diagnostic accuracy in both analyses, at 92 % for SBA and 96 % for LBA. In 11 patients (24 %) the PET findings modified the therapeutic strategy, the modification proving appropriate in 10 of them. {sup 11}C-Choline PET

  10. The role of renal scintigraphy and unenhanced helical computerized tomography in patients with ureterolithiasis.

    Science.gov (United States)

    Lorberboym, M; Kapustin, Z; Elias, S; Nikolov, G; Katz, R

    2000-04-01

    Unenhanced helical computerized tomography (UHCT) has recently evolved as an accurate imaging modality for determination of the presence or absence of ureterolithiasis in patients with acute flank pain. Functional renal scintigraphy is considered the gold standard for urinary tract obstruction. The objective of this study was to correlate the secondary signs of urinary obstruction on UHCT with findings of functional renal scintigraphy. UHCT was performed in 30 patients admitted to the emergency room with acute flank pain. All patients had a calcified urinary stone identified on UHCT. The location of each urinary stone was classified as ureteral or in the ureterovesical junction. The presence of secondary CT signs of ureteral obstruction was determined for each patient. After oral or intravenous hydration, a technetium-99m diethylene triamine penta-acetic acid renal scan was performed in all patients within 12 h of the CT scan. Follow-up delayed scintigraphic images were obtained at 2 h and 24 h in patients with evidence of ureteral obstruction. The sensitivity, specificity and predictive values of each possible combination of CT findings were determined by comparison with the scintigraphic results. The distal ureter was the most common location for a calculus on UHCT, followed in frequency by the ureterovesical junction, proximal ureter and mid-ureter. The renograms showed high-grade, unilateral obstruction in 12 patients, indeterminate scans in five patients and normal renograms in 13 patients. The sensitivities and specificities of individual CT findings ranged from 50% to 75% and from 8% to 69%, respectively. Perinephric stranding gave the highest positive predictive value (PPV) for obstruction (69% including indeterminate renograms). None of the individual CT findings showed a statistically significant correlation with scintigraphic findings. A combination of one or two positive CT findings had a PPV of only 25% for obstruction. A combination of three or four

  11. Feasibility of low-concentration iodinated contrast medium with lower-tube-voltage dual-source CT aortography using iterative reconstruction: comparison with automatic exposure control CT aortography.

    Science.gov (United States)

    Shin, Hee Jeong; Kim, Song Soo; Lee, Jae-Hwan; Park, Jae-Hyeong; Jeong, Jin-Ok; Jin, Seon Ah; Shin, Byung Seok; Shin, Kyung-Sook; Ahn, Moonsang

    2016-06-01

    To evaluate the feasibility of low-concentration contrast medium (CM) for vascular enhancement, image quality, and radiation dose on computed tomography aortography (CTA) using a combined low-tube-voltage and iterative reconstruction (IR) technique. Ninety subjects underwent dual-source CT (DSCT) operating in dual-source, high-pitch mode. DSCT scans were performed using both high-concentration CM (Group A, n = 50; Iomeprol 400) and low-concentration CM (Group B, n = 40; Iodixanol 270). Group A was scanned using a reference tube potential of 120 kVp and 120 reference mAs under automatic exposure control with IR. Group B was scanned using low-tube-voltage (80 or 100 kVp if body mass index ≥25 kg/m(2)) at a fixed current of 150 mAs, along with IR. Images of the two groups were compared regarding attenuation, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), iodine load, and radiation dose in various locations of the CTA. In comparison between Group A and Group B, the average mean attenuation (454.73 ± 86.66 vs. 515.96 ± 101.55 HU), SNR (25.28 ± 4.34 vs. 31.29 ± 4.58), and CNR (21.83 ± 4.20 vs. 27.55 ± 4.81) on CTA in Group B showed significantly greater values and significantly lower image noise values (18.76 ± 2.19 vs. 17.48 ± 3.34) than those in Group A (all Ps < 0.05). Homogeneous contrast enhancement from the ascending thoracic aorta to the infrarenal abdominal aorta was significantly superior in Group B (P < 0.05). Low-concentration CM and a low-tube-voltage combination technique using IR is a feasible method, showing sufficient contrast enhancement and image quality.

  12. Clinical evaluation of lumbar CT assisted discography in comparison with human cadaver

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Shigehiko

    1988-04-01

    In order to estimate the clinical value of lumbar CT assisted discography (CTD), results obtained by this method were compared with histological findings of the cross section of the spine in fresh human cadavera. Based on these findings, preoperative CTD of lumbar disc herniation was investigated. In the discs of human cadavera, the contrast medium mainly invaded the fissures of nucleus pulposus and the ruptures of annulus fibrosus and then diffused to the surrounding tissues. These ruptures were classified into two categories: radial and circumferential. This indentification was possible only in CTD and was obscure in the usual discogram. Not all the ruptures could be dyed in a severe degenerative disc, and a rupture which was not communicated with nucleus pulposus was not dyed in a mild degenerative disc. In the preoperative CTD of lumbar disc herniation, the posterior radial ruptures representing the route of herniated nuclei were characteristic and the circumferential ruptures were found complicated.

  13. Topology of helical fluid flow

    DEFF Research Database (Denmark)

    Andersen, Morten; Brøns, Morten

    2014-01-01

    Considering a coordinate-free formulation of helical symmetry rather than more traditional definitions based on coordinates, we discuss basic properties of helical vector fields and compare results from the literature obtained with other approaches. In particular, we discuss the role of the stream...

  14. Helical image-guided stereotactic body radiotherapy (SBRT) for the treatment of early-stage lung cancer: a single-institution experience at the Willis-Knighton Cancer Center.

    Science.gov (United States)

    Rosen, Lane R; Fischer-Valuck, Benjamin W; Katz, Sanford R; Durci, Michael; Wu, Hsinshun Terry; Syh, Joseph; Syh, Jarron; Patel, Bijal

    2014-01-01

    Our aim is to report on the clinical methods and outcomes of helical intensity-modulated stereotactic body radiotherapy (SBRT) for the treatment of early-stage non-small cell lung cancer (NSCLC). Seventy-nine patients with stage I NSCLC underwent helical SBRT with 48 Gy in 4 fractions or 60 Gy in 5 fractions. All patients underwent 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) or FDG-PET/computed tomography (CT) scanning in the immobilized treatment position for planned fusion with a separate kilovoltage (KV) CT simulation prior to treatment. Megavoltage CT images were obtained on the treatment unit prior to therapy and repeated at mid-fraction with comparison and fusion to the KV CT simulation planning images to assure setup accuracy. Serial follow-up with FDG-PET or FDG-PET/CT was performed at 3-4 months and every 6 months thereafter. Median follow-up was 27 months (range, 4-82 months). Overall local control rate (LCR) was 93.6% (95% confidence interval [CI], 86.0-97.3%) and 3-year overall survival (OS) was 58.4% (95% CI, 47.2-69.5%). For patients with T1N0M0 disease (n = 59) the LCR was 94.9% (95% CI, 86.1-98.3%) and the 3-year OS was 62.8% (95% CI, 49.9-73.9%). Patients treated with 60 Gy had longer 3-year OS than patients treated with 48 Gy (65.2% vs 37.5%; P = 0.044). SBRT-related toxicity was modest, with 10 patients developing grade 1/2 chest wall toxicity based on the Common Terminology Criteria for Adverse Events (CTCAE). Image-guided SBRT with helical IMRT delivered in 4 or 5 fractions of 12 Gy with rigid immobilization, FDG-PET-assisted targeting, and repeat mid-fraction CT scan is an effective treatment for early NSCLC.

  15. CT urography: a comparison of strategies for upper urinary tract opacification

    Energy Technology Data Exchange (ETDEWEB)

    Sanyal, Rupan; Deshmukh, Amol; Singh Sheorain, Virender; Taori, Kishor [Government Medical College, Department of Radiology, Nagpur (India)

    2007-05-15

    A consensus is yet to be reached regarding the best strategy for ensuring maximum ureteric delineation during CT urography (CTU). In this study we have compared various CTU protocols to try to establish the best method for ureteric delineation. Saline infusion in the supine position, saline infusion in the prone position, furosemide administration (10 mg, iv) and buscopan administration (20 mg iv) with saline infusion in the prone position were tried in four groups, each having 15 patients who were undergoing CTU. The pelvicalyceal system and ureter were divided into six segments, to each of which an opacification score was assigned (0, unopacified segment; 1, less than 50% opacified segment; 2, 50-99% of the segment opacified; or 3, completely opacified segment) and the results compared. Furosemide administration resulted in complete opacification of 93% of the ureters (28 of 30). In the distal (below the sciatic notch) ureter, the mean score with furosemide was 2.9, while that with saline, supine and prone positioning was 1.87 and 1.83, respectively, and this difference was highly significant (P = 0.0002 and P = 0.0001). It was also significantly higher than the buscopan group (score 2.3, P = 0.002). Also in the lower (the iliac crest to the sciatic notch) and upper (above the iliac crest) ureter, furosemide had significantly higher scores than saline infusion in either position. Saline infusion in the supine and prone positions had very similar scores in all segments that were less than the buscopan group, but this difference was not statistically significant. During CT urography, furosemide administration in low doses is the most effective and convenient technique for ureteric opacification. (orig.)

  16. Helicity in dynamic atmospheric processes

    Science.gov (United States)

    Kurgansky, M. V.

    2017-03-01

    An overview on the helicity of the velocity field and the role played by this concept in modern research in the field of geophysical fluid dynamics and dynamic meteorology is given. Different (both previously known in the literature and first presented) formulations of the equation of helicity balance in atmospheric motions (including those with allowance for effects of air compressibility and Earth's rotation) are brought together. Equations and relationships are given which are valid in different approximations accepted in dynamic meteorology: Boussinesq approximation, quasi-static approximation, and quasi-geostrophic approximation. Emphasis is placed on the analysis of helicity budget in large-scale quasi-geostrophic systems of motion; a formula for the helicity flux across the upper boundary of the nonlinear Ekman boundary layer is given, and this flux is shown to be exactly compensated for by the helicity destruction inside the Ekman boundary layer.

  17. Comparison of integrated whole-body PET/MR and PET/CT: Is PET/MR alternative to PET/CT in routine clinical oncology?

    Science.gov (United States)

    Ishii, Shirou; Shimao, Daisuke; Hara, Takamitsu; Miyajima, Masayuki; Kikuchi, Ken; Takawa, Masashi; Kumamoto, Kensuke; Ito, Hiroshi; Shishido, Fumio

    2016-04-01

    To compare the diagnostic accuracy of whole-body PET/CT and integrated PET/MR in relation to the total scan time durations. One hundred and twenty-three (123) patients (40 males and 83 females; mean age 59.6 years; range 20-83 years) with confirmed primary cancer and clinical suspicion of metastatic disease underwent whole-body 18F-FDG-PET/CT and 18F-FDG-PET/MR. Data acquisition was done after intravenous administration of 110-301 MBq radioactivity of 18F-FDG, and PET/MR data were acquired after the PET/CT data acquisition. The mean uptake times for PET/CT and PET/MR acquisition were 68.0 ± 8.0 and 98.0 ± 14 min, respectively. Total scan time was 20.0 and 25.0 min for whole-body PET/CT and PET/MR imaging. The reconstructed PET/CT and PET/MR data detected 333/355 (93.8 %) common lesions in 111/123 (90.2 %) patients. PET/CT and PET/MR alone detected 348/355 and 340/355 lesions, respectively. No significant (p = 0.08) difference was observed for the overall detection efficiency between the two techniques. On the other hand, a significant difference was observed between the two techniques for the detection of lung (p = 0.003) and cerebrospinal (p = 0.007) lesions. The 15 lesions identified by PET/CT only included 8 lung, 3 lymph nodes, 2 bone, and 1 each of peritoneal and adrenal gland lesions. On the other hand, 7 (6 brain metastatic lesions and 1 bone lesion) were identified by PET/MR only. Integrated PET/MR is a feasible whole-body imaging modality and may score better than PET/CT for the detection of brain metastases. To further prove diagnostic utility, this technique requires further clinical validation.

  18. Dual-time FDG-PET/CT in patients with potential breast cancer recurrence: Head-to-head comparison with CT and bone scintigraphy

    DEFF Research Database (Denmark)

    Baun, Christina; Falch Braas, Kirsten; Gerke, Oke

    to evaluate the diagnostic accuracy of FDG PET/CT performed one and three hours after injection compared with CT and bone scintigraphy in patients suspected of BC recurrence Methods and materials: 39 patients suspected either clinically or diagnostically of BC recurrence were included. All patients underwent...... of six hours and had a blood glucose level less than 8 mmol/l prior to injection of 4 MBq/kg of FDG. Imaging was performed 1 and 3 hours (±5 mins) after injection. At both time-points a low-dose CT from the skull to the proximal femur was obtained followed by a 3D PET-scan of the same area. The duration....... CT. Contrast-enhanced diagnostic CT of the thorax and the upper abdomen was performed at the Department of Radiology according to their current guidelines. The patients were scanned from the seventh cervical vertebra to the upper abdomen including the liver. 100 ml of Optiray 300 mg I/ml were...

  19. Comparison of MR-based attenuation correction vs. CT-based attenuation correction of Whole Body PET/MR imaging

    Science.gov (United States)

    Izquierdo-Garcia, David; Sawiak, Stephen J.; Knesaurek, Karin; Narula, Jagat; Fuster, Valentin; Machac, Joseph; Fayad, Zahi A.

    2014-01-01

    Purpose The objective of this paper was to evaluate the performance of the built-in MR-based attenuation correction method (MRAC) included in the combined whole-body Ingenuity TF PET/MR scanner and compare it to the gold standard CT-based attenuation correction (CTAC). Methods Twenty-six patients undergoing clinical whole body FDG-PET/CT imaging were subsequently scanned on the PET/MR (mean delay 100min). Patients were separated in two groups: alpha group (N=14) with no MR coils during PET/MR imaging and beta group (N=12) including MR coils (Neuro-Vascular, Spine, Cardiac or Torso coils). All images were coregistered to the same space (PET/MR). Voxel- and region-based (10 regions of interest, ROIs) comparisons were made between the 2 PET images from PET/MR: using MRAC and CTAC. Additional comparison of lesions performed by an experienced clinician was also reported. Results Body mass index (BMI) and lung density showed significant differences between alpha and beta groups. Right vs. left lung density was also significantly different within each group. Overall the beta group (with coils) presented higher MRAC PET values than the alpha group when compared to the CTAC (alpha: −0.2±33.6%, R2=0.98, p<0.001, beta: 10.31±69.86%, R2=0.97, p<0.001). Conclusion In comparison to CTAC, PET values with MRAC method were underestimated by less than 10% on average, although some ROIs and lesions do differ by more (such as spine, lung or heart). The beta group (with coils) showed increased overall PET quantification as well as increased variability when compared to the alpha group (no coils). PET reconstructed with MRAC showed some differences when compared to PET reconstructed with CTAC, mostly due to air pockets, metallic implants and attenuation differences in big bone areas (such as pelvis and spine) due to the segmentation limitation of the MRAC method. PMID:24652234

  20. SimDoseCT: dose reporting software based on Monte Carlo simulation for a 320 detector-row cone-beam CT scanner and ICRP computational adult phantoms

    Science.gov (United States)

    Cros, Maria; Joemai, Raoul M. S.; Geleijns, Jacob; Molina, Diego; Salvadó, Marçal

    2017-08-01

    This study aims to develop and test software for assessing and reporting doses for standard patients undergoing computed tomography (CT) examinations in a 320 detector-row cone-beam scanner. The software, called SimDoseCT, is based on the Monte Carlo (MC) simulation code, which was developed to calculate organ doses and effective doses in ICRP anthropomorphic adult reference computational phantoms for acquisitions with the Aquilion ONE CT scanner (Toshiba). MC simulation was validated by comparing CTDI measurements within standard CT dose phantoms with results from simulation under the same conditions. SimDoseCT consists of a graphical user interface connected to a MySQL database, which contains the look-up-tables that were generated with MC simulations for volumetric acquisitions at different scan positions along the phantom using any tube voltage, bow tie filter, focal spot and nine different beam widths. Two different methods were developed to estimate organ doses and effective doses from acquisitions using other available beam widths in the scanner. A correction factor was used to estimate doses in helical acquisitions. Hence, the user can select any available protocol in the Aquilion ONE scanner for a standard adult male or female and obtain the dose results through the software interface. Agreement within 9% between CTDI measurements and simulations allowed the validation of the MC program. Additionally, the algorithm for dose reporting in SimDoseCT was validated by comparing dose results from this tool with those obtained from MC simulations for three volumetric acquisitions (head, thorax and abdomen). The comparison was repeated using eight different collimations and also for another collimation in a helical abdomen examination. The results showed differences of 0.1 mSv or less for absolute dose in most organs and also in the effective dose calculation. The software provides a suitable tool for dose assessment in standard adult patients undergoing CT

  1. MRI in preoperative evaluation of chronic paranasal sinusitis - a comparison with CT; MRT in der praeoperativen Diagnostik der chronischen Sinusitis im Vergleich mit der CT

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, F.; Habermann, C.R.; Welger, J.; Steiner, P.; Rozeh, B.; Buecheler, E. [Universitaetsklinikum Hamburg-Eppendorf (Germany). Klinik und Poliklinik fuer Radiologie; Knaape, A.; Metternich, F. [Universitaetsklinikum Hamburg-Eppendorf (Germany). Klinik und Poliklinik fuer Hals-, Nasen- und Ohrenheilkunde; Schoder, V. [Universitaetsklinikum Hamburg-Eppendorf (Germany). Inst. fuer Mathematik und Datenverarbeitung in der Medizin

    2001-04-01

    Purpose: To determine the value of MRI in the preoperative evaluation of chronic paranasal sinusitis and to compare the results with CT and intraoperative findings. Method/Materials: 42 patients with clinical signs of chronic paranasal sinusitis underwent MRI after CT evaluation on one day, with subsequent functional endoscopic sinus surgery on the next day. Coronary CT was obtained with 5-mm slices and table-feed in the prone position, while MRI was performed in the supine position with coronary T{sub 2}-TSE+pd and coronary and transverse HASTE, each with 5-mm slice thickness. Aquisition time in MRI was less than 8 minutes. Two radiologists reviewed the CT and MRI scans for signs of sinusitis and detection of anatomical landmarks. The results were correlated with the intraoperative findings. Results: MRI offered no artifacts of dental work and showed more often high quality pictures than CT. CT and MRI demonstrated a good correlation in the detection of mucosal pathologies ({kappa}=0.46-0.87) and anatomic variants ({kappa}=0.55-0.86). All important anatomical structures could be evaluated sufficiently with MRI for preoperative management. Both diagnostic tools showed an unsatisfactory correlation with intraoperative findings in the ethmoidal complex and maxillary sinus ({tau}=-0.08-0.3). (orig.) [German] Zielsetzung: Einschaetzung des Stellenwertes der MRT in der Beurteilung der praeoperativen Diagnostik der chronischen Sinusitis und Vergleich mit koronarer CT und intraoperativem Befund. Material und Methodik: 42 Patientinnen mit klinischen Zeichen einer chronischen Sinusitis wurden jeweils innerhalb eines Tages mittels CT und MRT untersucht. Am Folgetag wurde eine transnasale endoskopische Operation an den Nasennebenhoehlen durchgefuehrt. Die CT erfolgte in Bauchlage und koronarer Schichtfuehrung (5 mm Schichtdicke und Tischvorschub). Die MRT wurde an einem 1,5 T-Geraet in Rueckenlage mittels Kopfspule durchgefuehrt. Eingesetzt wurden koronare Protonen-w-, T

  2. Model-based iterative reconstruction for reduction of radiation dose in abdominopelvic CT: comparison to adaptive statistical iterative reconstruction

    OpenAIRE

    Yasaka, Koichiro; Katsura, Masaki; Akahane, Masaaki; Sato, Jiro; Matsuda, Izuru; Ohtomo, Kuni

    2013-01-01

    Purpose To evaluate dose reduction and image quality of abdominopelvic computed tomography (CT) reconstructed with model-based iterative reconstruction (MBIR) compared to adaptive statistical iterative reconstruction (ASIR). Materials and methods In this prospective study, 85 patients underwent referential-, low-, and ultralow-dose unenhanced abdominopelvic CT. Images were reconstructed with ASIR for low-dose (L-ASIR) and ultralow-dose CT (UL-ASIR), and with MBIR for ultralow-dose CT (UL-MBIR...

  3. Inter-observer agreement of CT measurement of the glenoid bone surface by the CT Pico method: Comparison with laser in a cadaveric model

    Energy Technology Data Exchange (ETDEWEB)

    De Filippo, Massimo; Saba, Luca; Negrini, Giulio; Silva, Mario [University of Parma, Department of Radiology, Parma (Italy); Pedrazzi, Giuseppe [Universita di Parma, Department of Neuroscience. Unita di Biofisica e Fisica Medica - Plesso Biotecnologico Integrato, Parma (Italy); Pogliacomi, Francesco [University of Parma, Department of Orthopedic Surgery, Parma (Italy); Castagna, Alessandro [Istituto Clinico Humanitas, Section of Orthopedic Surgery, Rozzano, MI (Italy)

    2015-10-15

    The aim of this study was to test reproducibility of the CT Pico method in a cadaveric model and to compare CT Pico measurements with a high-precision laser probe for optical scanning. The glenoid surface of ten dried cadaveric scapulae (with intact surface) was measured by and high-precision laser probe for optical scanning, the latter being assumed as a reference standard. Measurements were done according to the Pico technique, using a circle-shaped region of interest (ROI) that was placed on the inferior glenoid rim. Measurements obtained using the CT Pico method (three readers) and with laser were compared to assess differences between radiological assessment and the reference standard. Each observer performed two repeated measurements from each scapulae (20 for each observer). Mean differences between laser measurements and each CT reader were 18.4 % (range, -4 to 61 %) for reader 1, 12.4 % (range, -15 to 64 %) for reader 2, and 11 % (range, -14 to 58 %) for reader 3. Considering all the 60 measurements made by the three readers, 39 measurements out of 60 (65 %) were outside the range [-5 %; +5 %] while 26 measurements (43 %) are outside the range [-10 %; +10 %]. The largest differences (positive and negative) were +64 and -14 %, respectively. Intra-operator reproducibility was high in most cases intraclass correlation coefficient (ICC) =0.93, ICC = 0.91, ICC = 0.93 and Lin's Concordance correlation coefficient (CCC) = 0.92, CCC = 0.90, CCC = 0.92 for reader 1 to 3, respectively. However, in five cases the CT Pico measurements showed absolute differences between the first and second measurements that exceeded 10 %. The inter-observer variability for CT measurement of the glenoid surface using the CT Pico method was high when compared with laser, in the assessment of glenoid surface in cadaveric specimens, thus the CT Pico method is not reliable and could cause errors in the clinical management of the patient. Level of evidence. Level II, Development of

  4. Inter-observer agreement of CT measurement of the glenoid bone surface by the CT Pico method: Comparison with laser in a cadaveric model.

    Science.gov (United States)

    De Filippo, Massimo; Saba, Luca; Negrini, Giulio; Silva, Mario; Pedrazzi, Giuseppe; Pogliacomi, Francesco; Castagna, Alessandro

    2015-10-01

    The aim of this study was to test reproducibility of the CT Pico method in a cadaveric model and to compare CT Pico measurements with a high-precision laser probe for optical scanning. The glenoid surface of ten dried cadaveric scapulae (with intact surface) was measured by and high-precision laser probe for optical scanning, the latter being assumed as a reference standard. Measurements were done according to the Pico technique, using a circle-shaped region of interest (ROI) that was placed on the inferior glenoid rim. Measurements obtained using the CT Pico method (three readers) and with laser were compared to assess differences between radiological assessment and the reference standard. Each observer performed two repeated measurements from each scapulae (20 for each observer). Mean differences between laser measurements and each CT reader were 18.4% (range, -4 to 61%) for reader 1, 12.4% (range, -15 to 64%) for reader 2, and 11% (range, -14 to 58%) for reader 3. Considering all the 60 measurements made by the three readers, 39 measurements out of 60 (65%) were outside the range [-5%; +5%] while 26 measurements (43%) are outside the range [-10%; +10%]. The largest differences (positive and negative) were +64 and -14 %, respectively. Intra-operator reproducibility was high in most cases (intraclass correlation coefficient (ICC) =0.93, ICC = 0.91, ICC = 0.93 and Lin's Concordance correlation coefficient (CCC) = 0.92, CCC = 0.90, CCC = 0.92 for reader 1 to 3, respectively. However, in five cases the CT Pico measurements showed absolute differences between the first and second measurements that exceeded 10%. The inter-observer variability for CT measurement of the glenoid surface using the CT Pico method was high when compared with laser, in the assessment of glenoid surface in cadaveric specimens, thus the CT Pico method is not reliable and could cause errors in the clinical management of the patient. Level of evidence Level II, Development of

  5. Analysis of clinical trials of biosimilar infliximab (CT-P13) and comparison against historical clinical studies with the infliximab reference medicinal product.

    Science.gov (United States)

    Yoo, Dae Hyun; Oh, Choongseob; Hong, SeungSuh; Park, Won

    2015-01-01

    To examine whether efficacy, safety and pharmacokinetic (PK) data observed with CT-P13 (Remsima(®); Inflectra(®)), an infliximab biosimilar, are similar to those from published reports with the reference medicinal product (RMP; Remicade(®)) in patients with rheumatoid arthritis (RA) or ankylosing spondylitis (AS). Literature searches were performed to identify clinical studies with infliximab RMP. Efficacy, safety and PK data were indirectly compared with data from head-to-head clinical trials of CT-P13 and RMP. CT-P13 and RMP produce similar efficacy in patients with RA and AS when compared across clinical studies. There are no substantial differences in the incidence of infusion-related reactions, infections, serious infections, malignancy or lymphoma. PK data in patients with RA are similar in direct comparisons and comparisons with historical data. Efficacy, safety and PK data are highly comparable between CT-P13 and RMP, both in head-to-head clinical studies, and indirect comparisons with historical clinical data for RMP.

  6. Forming Simulation of Thick AFP Laminates and Comparison with Live CT Imaging

    Science.gov (United States)

    Leutz, Daniel; Vermilyea, Mark; Bel, Sylvain; Hinterhölzl, Roland

    2016-08-01

    Automated fiber placement (AFP) process can be used to manufacture laminates by laying up unidirectional slit tapes along a desired path and placing multiple layers on top of each other. Usually, the slit tapes are placed direct onto the tooling to attain the final part geometry. Alternatively, the laminate can be built up on a planar substrate and can be subsequently formed into the final shape. This kind of processing allows manufacturing highly curved parts, which may not be possible with the direct placement. In the present work a forming simulation of thick AFP laminates is developed to predict the tapes' orientations and delamination as well as transverse tape spread-ups and separations during the forming process. The simulation model is built up through the material characterization experiments. Validation is performed comparing the results of the simulation vs. the experimental forming on two generic geometries. An optical inspection is made on the external layers of the laminates. In a second step, live computer tomography (CT) scans are used to inspect the tapes within an AFP laminate during forming of an L- and a Z-flange. Tapes re-orientation, gaps and tapes widening are observed experimentally and compared to the simulation results. The simulation is capable to predict the tows orientation and provides indicators concerning the tows spread-up and separation.

  7. SPEECH AND LANGUAGE DISORDERS IN PATIENTS WITH CVA COMPARISON WITH CT SCAN

    Directory of Open Access Journals (Sweden)

    A CHIT SAZ

    2001-09-01

    Full Text Available Introduction. Stroke is a sudden onset of neurologic signs as a result of the ischemic or intracranial hemmorhage because of the cerebrovascular disease that stands for at least 24 hours. Cerebrovascular disease is one of the most important factors that causes speech disorder. The aim of this study is to show the characteristics of speech and language related to the various parts of the brain lesion. Methods. In this study 64 patients with CVA and speech disorders were tested. Lesions in 36 patients were ischemic, 17 patients were hemmorhagic. 11 patients had no any significant lesion on CT-scan. The test unndertaken included "Farsi Aphasia Test" written by Dr. Nilipoor. Results. Fifty percent of patients were in 61-70 years old group. 70.3 percent were male and 29.7 percent were female. In aspect of the hemisphere involved 50 percent were left hemisphere and 28.1 percent Right hemisphere and 4.7 percent with both hemisphers involvement. Discussion. In CVA patient with speech disorders the temporal lobe of the left hemisphere is mostly involved, and in respect to oral speech disorders in CVA, most of the problems were seen in non verbal fluency and the least problems were seen in repetition.

  8. Scapholunate kinematics of asymptomatic wrists in comparison with symptomatic contralateral wrists using four-dimensional CT examinations: initial clinical experience

    Energy Technology Data Exchange (ETDEWEB)

    Demehri, Shadpour; Hafezi-Nejad, Nima; Morelli, John N.; Thakur, Uma; Eng, John [Johns Hopkins University, Musculoskeletal Radiology, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Lifchez, Scott D.; Shores, Jaimie T. [Johns Hopkins University, Department of Plastic and Reconstructive Surgery, Baltimore, MD (United States); Means, Kenneth R. [MedStar Union Memorial Hospital, The Curtis National Hand Center, Baltimore, MD (United States)

    2016-04-15

    Using four-dimensional CT scan (4DCT), we aimed at showing the kinematics of scapholunate (SL) interval in asymptomatic wrists in comparison with symptomatic contralateral wrists with inconclusive radiographic findings. This is an IRB approved, HIPPA compliant, retrospective study. Patients suspected of SL interosseous ligament (SLIL) injuries were referred for further evaluation of chronic wrist pain (>3 months). Twelve wrists (11 subjects) with chronic symptoms and inconclusive plain radiographs and 10 asymptomatic wrists (in 10 different subjects) were scanned using 4DCT. The minimum SL interval was measured during three wrist motions: relaxed-to-clenched fist, flexion-to-extension, and radial-to-ulnar-deviation. Changes were recorded using double-oblique multiplanar reformation technique. We extracted the normal limits of the SL interval as measured by dynamic CT scanning during active motion in asymptomatic wrists. In asymptomatic wrists, the average SL interval was observed to be smaller than 1 mm during all motions. In symptomatic wrists, during exams performed with clenched fist (SL interval (mean ± SD) = 2.53 ± 1.19 mm), extension (2.54 ± 1.48 mm) or ulnar deviation (2.06 ± 1.12 mm), the average SL interval was more than 2 mm. In contrast to symptomatic wrists, no significant change in SL interval measurements was detected during wrist motions in asymptomatic wrists. There was a mild to moderate correlation between SL interval change and presence/absence of symptoms (point-biserial correlation coefficients: 0.29-0.55). In patients with wrist pain suspicious for SLIL injury and inconclusive radiographs, SL interval increase can be detected with 4DCT in the symptomatic wrist compared to the asymptomatic wrist. (orig.)

  9. Detection of pulmonary embolism with combined ventilation-perfusion SPECT and low-dose CT: head-to-head comparison with multidetector CT angiography

    DEFF Research Database (Denmark)

    Gutte, Henrik; Mortensen, Jann; Jensen, Claus Verner

    2009-01-01

    The diagnosis of pulmonary embolism (PE) is usually established by a combination of clinical assessment, D-dimer testing, and imaging with either pulmonary ventilation-perfusion (V/Q) scintigraphy or pulmonary multidetector CT (MDCT) angiography. Both V/Q SPECT and MDCT angiography seem to have...

  10. Comparison of integrated whole-body [{sup 11}C]choline PET/MR with PET/CT in patients with prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Souvatzoglou, Michael; Takei, Toshiki; Fuerst, Sebastian; Gaertner, Florian; Drzezga, Alexander; Ziegler, Sibylle; Nekolla, Stephan G.; Schwaiger, Markus; Beer, Ambros J. [Technische Universitaet Muenchen, Department of Nuclear Medicine, Munich (Germany); Eiber, Matthias; Rummeny, Ernst J. [Technische Universitaet Muenchen, Department of Radiology, Munich (Germany); Maurer, Tobias [Technische Universitaet Muenchen, Department of Urology, Munich (Germany); Geinitz, Hans [Technische Universitaet Muenchen, Department of Radiation Oncology, Munich (Germany)

    2013-10-15

    To evaluate the performance of conventional [{sup 11}C]choline PET/CT in comparison to that of simultaneous whole-body PET/MR. The study population comprised 32 patients with prostate cancer who underwent a single-injection dual-imaging protocol with PET/CT and subsequent PET/MR. PET/CT scans were performed applying standard clinical protocols (5 min after injection of 793 {+-} 69 MBq [{sup 11}C]choline, 3 min per bed position, intravenous contrast agent). Subsequently (52 {+-} 15 min after injection) PET/MR was performed (4 min per bed position). PET images were reconstructed iteratively (OSEM 3D), scatter and attenuation correction of emission data and regional allocation of [{sup 11}C]choline foci were performed using CT data for PET/CT and segmented Dixon MR, T1 and T2 sequences for PET/MR. Image quality of the respective PET scans and PET alignment with the respective morphological imaging modality were compared using a four point scale (0-3). Furthermore, number, location and conspicuity of the detected lesions were evaluated. SUVs for suspicious lesions, lung, liver, spleen, vertebral bone and muscle were compared. Overall 80 lesions were scored visually in 29 of the 32 patients. There was no significant difference between the two PET scans concerning number or conspicuity of the detected lesions (p not significant). PET/MR with T1 and T2 sequences performed better than PET/CT in anatomical allocation of lesions (2.87 {+-} 0.3 vs. 2.72 {+-} 0.5; p = 0.005). The quality of PET/CT images (2.97 {+-} 0.2) was better than that of the respective PET scan of the PET/MR (2.69 {+-} 0.5; p = 0.007). Overall the maximum and mean lesional SUVs exhibited high correlations between PET/CT and PET/MR ({rho} = 0.87 and {rho} = 0.86, respectively; both p < 0.001). Despite a substantially later imaging time-point, the performance of simultaneous PET/MR was comparable to that of PET/CT in detecting lesions with increased [{sup 11}C]choline uptake in patients with prostate

  11. Role of technetium-99m methylene diphosphonate SPECT/CT in the detection of sacroiliitis in patients with spondyloarthropathy - comparison with clinical markers and MRI.

    Science.gov (United States)

    Parghane, Rahul V; Singh, Baljinder; Sharma, Aman; Singh, Harmandeep; Singh, Paramjit; Bhattacharya, Anish

    2017-08-10

    Rationale: To evaluate the role of (99m)Tc-MDP SPECT/CT for the detection of sacroiliitis in spondyloarthopathies (SpA) and comparison with clinical markers and MRI. Methods: A total of 155 diagnosed patients (83M : 72 F; mean age 35.80±12.40 years; range 18-60 years ) with SpA as per the European Spondyloarthropathy Study Group criteria (ESSG) criteria were prospectively included All the patients were subjected to clinical evaluation (using BASDAI scoring), ESR, CRP levels, planar (99m)Tc MDP bone scintigraphy, hybrid SPECT/CT and MRI of the pelvic region. Using MRI as the reference criterion, diagnostic accuracy of clinical and scintigraphic parameters was assessed. On planar bone scintigraphy/SPECT, score of 0, 1, 2 was assigned when the tracer uptake in the SI joint was less than, equal to and more than the sacrum. A score of '2' was considered as positive for the diagnosis of sacroiliitis. Results: Using MRI as the reference standard, sensitivity, specificity, accuracy, positive predictive value and negative predictive value of (99m)Tc MDP SPECT/CT were 90.0%, 80.0%, 87.0%, 92.0%, and 75.0% respectively. The accuracy of SPECT/CT (87%) was better than ESR (58.1%), CRP (32.9%), BASDAI scoring (77%) and planar bone scintigraphy (53%). Similar results were found for sensitivity and negative predictive values. Specificity of SPECT/CT (80%) was lower than BASDAI scoring (88.6%) and equal to planar bone scintigraphy (80%). Positive predictive value of SPECT/CT (92%) was bit lower than BASDAI scoring (93.6%). Kappa values for planar (99m)Tc MDP bone scan and hybrid SPECT/CT were 0.167 and 0.673 indicating poor agreement for planar bone scan and good agreement for hybrid SPECT/CT images respectively. A significant (P <0.001) correlation (r= 0.659) was observed between SPECT/CT and MRI findings. Conclusion:(99m)Tc-MDP SPECT/CT imaging has diagnostic accuracy comparable to MRI for the evaluation of sacroiliitis in SpA and can thus be used as an alternative to MRI in

  12. Turbulent Dynamos and Magnetic Helicity

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Hantao

    1999-04-01

    It is shown that the turbulent dynamo alpha-effect converts magnetic helicity from the turbulent field to the mean field when the turbulence is electromagnetic while the magnetic helicity of the mean-field is transported across space when the turbulence is elcetrostatic or due to the elcetron diamagnetic effect. In all cases, however, the dynamo effect strictly conserves the total helicity expect for a battery effect which vanishes in the limit of magnetohydrodynamics. Implications for astrophysical situations, especially for the solar dynamo, are discussed.

  13. Comparison of high-resolution CT findings between miliary metastases and miliary tuberculosis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chan Sung; Lee, Ki Nam; Lee, Jin Hwa [Dong-A University College of Medicine, Pusan (Korea, Republic of)

    2003-02-01

    To compare the findings of high-resolution computed tomography (HRCT) between patients with miliary metastases and miliary tuberculosis. Between May 1998 and April 2002, 11 patients with miliary metastases and 18 with miliary tuberculosis underwent HRCT, and we reviewed the findings. In miliary metastases, the primary lesions were adenocarcinoma of the lung (n=2), stomach (n=1), or pancreas (n=1), or unknown origin (n=5), and papillary carcinoma of the thyroid (n=2). Two radiologists blinded to the clinical and pathologic data reached a consensus regarding nodule size and margin, their distribution and coalescence, interstitial involvement, and other ancillary HRCT findings. Data were analyzed using the chi-square test. CT scans showed numerous 1 to 5-mm nodules randomly distributed throughout both lungs of all patients. Nodules larger than 1.5 mm in diameter were more often seen in miliary metastases (81.9%). In six (54.5%) patients with miliary metastases and in three (16.7%) with miliary tuberculosis, nodule size varied (p<0.05). Pleural effusion occurred in three (27.3%) patients with miliary metastases and three (16.7%) with miliary tuberculosis. Interlobular septal thickening (100%) and peribronchovascular thickening (63.6%) were more common in miliary metastases than in miliary tuberculosis (p<0.01). Lymph node enlargement was seen in 11 (100%) patients with miliary metastases and five (27.8%) with miliary tuberculosis (P<0.001). At HRCT, lymph node enlargement and both interlobular and peribronchovascular thickening are more commonly observed in miliary metastases than in miliary tuberculosis.

  14. Pulmonary embolism in pregnancy: comparison of pulmonary CT angiography and lung scintigraphy.

    LENUS (Irish Health Repository)

    Ridge, Carole A

    2012-02-01

    OBJECTIVE: The purpose of this study was to retrospectively compare the diagnostic adequacy of lung scintigraphy with that of pulmonary CT angiography (CTA) in the care of pregnant patients with suspected pulmonary embolism. MATERIALS AND METHODS: Patient characteristics, radiology report content, additional imaging performed, final diagnosis, and diagnostic adequacy were recorded for pregnant patients consecutively referred for lung scintigraphy or pulmonary CTA according to physician preference. Measurements of pulmonary arterial enhancement were performed on all pulmonary CTA images of pregnant patients. Lung scintigraphy and pulmonary CTA studies deemed inadequate for diagnosis at the time of image acquisition were further assessed, and the cause of diagnostic inadequacy was determined. The relative contribution of the inferior vena cava to the right side of the heart was measured on nondiagnostic CTA images and compared with that on CTA images of age-matched nonpregnant women, who were the controls. RESULTS: Twenty-eight pulmonary CTA examinations were performed on 25 pregnant patients, and 25 lung scintigraphic studies were performed on 25 pregnant patients. Lung scintigraphy was more frequently adequate for diagnosis than was pulmonary CTA (4% vs 35.7%) (p = 0.0058). Pulmonary CTA had a higher diagnostic inadequacy rate among pregnant than nonpregnant women (35.7% vs 2.1%) (p < 0.001). Transient interruption of contrast material by unopacified blood from the inferior vena cava was identified in eight of 10 nondiagnostic pulmonary CTA studies. CONCLUSION: We found that lung scintigraphy was more reliable than pulmonary CTA in pregnant patients. Transient interruption of contrast material by unopacified blood from the inferior vena cava is a common finding at pulmonary CTA of pregnant patients.

  15. Comparison of tibiofemoral joint space width measurements from standing CT and fixed flexion radiography.

    Science.gov (United States)

    Segal, Neil A; Frick, Eric; Duryea, Jeffrey; Nevitt, Michael C; Niu, Jingbo; Torner, James C; Felson, David T; Anderson, Donald D

    2017-07-01

    The objective of this project was to determine the relationship between medial tibiofemoral joint space width measured on fixed-flexion radiographs and the three-dimensional joint space width distribution on low-dose, standing CT (SCT) imaging. At the 84-month visit of the Multicenter Osteoarthritis Study, 20 participants were recruited. A commercial SCT scanner for the foot and ankle was modified to image knees while standing. Medial tibiofemoral joint space width was assessed on radiographs at fixed locations from 15% to 30% of compartment width using validated software and on SCT by mapping the distances between three-dimensional subchondral bone surfaces. Individual joint space width values from radiographs were compared with three-dimensional joint space width values from corresponding sagittal plane locations using paired t-tests and correlation coefficients. For the four medial-most tibiofemoral locations, radiographic joint space width values exceeded the minimal joint space width on SCT by a mean of 2.0 mm and were approximately equal to the 61st percentile value of the joint space width distribution at each respective sagittal-plane location. Correlation coefficients at these locations were 0.91-0.97 and the offsets between joint space width values from radiographs and SCT measurements were consistent. There were greater offsets and variability in the offsets between modalities closer to the tibial spine. Joint space width measurements on fixed-flexion radiographs are highly correlated with three-dimensional joint space width from SCT. In addition to avoiding bony overlap obscuring the joint, a limitation of radiographs, the current study supports a role for SCT in the evaluation of tibiofemoral OA. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1388-1395, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  16. Estimation of diastolic filling pressure with cardiac CT in comparison with echocardiography using tissue doppler imaging: Determination of optimal CT reconstruction parameters

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Ji Sun; Suh, Jon; Lee, Heon [Soonchunhyang University Hospital Bucheon, Bucheon (Korea, Republic of); Lee, Bora [Dept. of Biostatistics, Soonchunhyang University College of Medicine, Seoul (Korea, Republic of); Lee, Soo Jeong [Terarecon Korea, Seoul (Korea, Republic of); Jou, Sung Shick [Dept. of Radiology, Soonchunhyang University Hospital Cheonan, Cheonan (Korea, Republic of); Lim, Hyun Kyung [Dept. of Radiology, Soonchunhyang University Hospital Seoul, Seoul (Korea, Republic of)

    2017-08-01

    To determine the optimal CT image reconstruction parameters for the measurement of early transmitral peak velocity (E), early peak mitral septal tissue velocity (E′), and E / E′. Forty-six patients underwent simultaneous cardiac CT and echocardiography on the same day. Four CT datasets were reconstructed with a slice thickness/interval of 0.9/0.9 mm or 3/3 mm at 10 (10% RR-interval) or 20 (5% RR-interval) RR-intervals. The E was calculated by dividing the peak transmitral flow (mL/s) by the corresponding mitral valve area (cm{sup 2}). E′ was calculated from the changes in the left ventricular length per cardiac phase. E / E′ was then estimated and compared with that from echocardiography. For assessment of E / E′, CT and echocardiography were more strongly correlated (p < 0.05) with a slice thickness of 0.9 mm and 5% RR-interval (r = 0.77) than with 3 mm or 10% RR-interval. The diagnostic accuracy of predicting elevated filling pressure (E / E′ ≥ 13, n = 14) was better with a slice thickness of 0.9 mm and 5% RR-interval (87.0%) than with 0.9 mm and 10% RR-interval (71.7%) (p = 0.123) and significantly higher than that with a slice thickness of 3 mm with 5% (67.4%) and 10% RR-interval (63.0%), (p < 0.05), respectively. Data reconstruction with a slice thickness of 0.9 mm at 5% RR-interval is superior to that with a slice thickness of 3 mm or 10% RR-interval in terms of the correlation of E / E′ between CT and echocardiography. Thin slices and frequent sampling also allow for more accurate prediction of elevated filling pressure.

  17. Regadenoson-stress myocardial CT perfusion and single-photon emission CT: rationale, design, and acquisition methods of a prospective, multicenter, multivendor comparison.

    Science.gov (United States)

    Cury, Ricardo C; Kitt, Therese M; Feaheny, Kathleen; Akin, Jamie; George, Richard T

    2014-01-01

    Pharmacologic stress myocardial CT perfusion (CTP) has been reported to be a viable imaging modality for detection of myocardial ischemia compared with single-photon emission CT (SPECT) in several single-center studies. However, regadenoson-stress CTP has not previously been compared with SPECT in a multicenter, multivendor study. The rationale and design of a phase 2, randomized, cross-over study of regadenoson-stress myocardial perfusion imaging by CTP compared with SPECT are described herein. The study will be conducted at approximately 25 sites by using 6 different CT scanner models, including 64-, 128-, 256-, and 320-slice systems. Subjects with known/suspected coronary artery disease will be randomly assigned to 1 of 2 imaging procedure sequences; rest and regadenoson-stress SPECT on day 1, then regadenoson-stress CTP and rest CTP/coronary CT angiography (same acquisition) on day 2; or regadenoson-stress CTP and rest CTP/CT angiography on day 1, then rest and regadenoson-stress SPECT on day 2. The prespecified primary analysis examines the agreement rate between CTP and SPECT for detecting or excluding ischemia (≥2 or 0-1 reversible defects, respectively), as assessed by 3 independent blinded readers for each modality. Non-inferiority will be indicated if the lower boundary of the 95% CI for the agreement rate is within 0.15 of 0.78 (the observed agreement rate in the regadenoson pivotal trials). The protocol described herein will support the first evaluation of regadenoson-stress CTP by using multiple scanner types compared with SPECT. Copyright © 2014 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  18. Optimizing radiation exposure for CT localizer radiographs.

    Science.gov (United States)

    Bohrer, Evelyn; Schäfer, Stefan; Mäder, Ulf; Noël, Peter B; Krombach, Gabriele A; Fiebich, Martin

    2017-06-01

    The trend towards submillisievert CT scans leads to a higher dose fraction of localizer radiographs in CT examinations. The already existing technical capabilities make dose optimization of localizer radiographs worthwhile. Modern CT scanners apply automatic exposure control (AEC) based on attenuation data in such a localizer. Therefore not only this aspect but also the detectability of anatomical landmarks in the localizer for the desired CT scan range adjustment needs to be considered. The effective dose of a head, chest, and abdomen-pelvis localizer radiograph with standard factory settings and user-optimized settings was determined using Monte Carlo simulations. CT examinations of an anthropomorphic phantom were performed using multiple sets of acquisition parameters for the localizer radiograph and the AEC for the subsequent helical CT scan. Anatomical landmarks were defined to assess the image quality of the localizer. CTDIvol and effective mAs per slice of the helical CT scan were recorded to examine the impact of localizer settings on a helical CT scan. The dose of the localizer radiograph could be decreased by more than 90% while the image quality remained sufficient when selecting the lowest available settings (80kVp, 20mA, pa tube position). The tube position during localizer acquisition had a greater impact on the AEC than the reduction of tube voltage and tube current. Except for the use of a pa tube position, all changes of acquisition parameters for the localizer resulted in a decreased total radiation exposure. A dose reduction of CT localizer radiograph is necessary and possible. In the examined CT system there was no negative impact on the modulated helical CT scan when the lowest tube voltage and tube current were used for the localizer. Copyright © 2016. Published by Elsevier GmbH.

  19. Optimizing radiation exposure for CT localizer radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Bohrer, Evelyn; Maeder, Ulf; Fiebich, Martin [Univ. of Applied Sciences, Giessen (Germany). Inst. of Medical Physics and Radiation Protection-IMPS; Schaefer, Stefan; Krombach, Gabriele A. [Univ. Hospital Giessen (Germany). Dept. of Radiology; Noel, Peter B. [Technische Univ. Muenchen (Germany). Dept. of Diagnostic and Interventional Radiology

    2017-08-01

    The trend towards submillisievert CT scans leads to a higher dose fraction of localizer radiographs in CT examinations. The already existing technical capabilities make dose optimization of localizer radiographs worthwhile. Modern CT scanners apply automatic exposure control (AEC) based on attenuation data in such a localizer. Therefore not only this aspect but also the detectability of anatomical landmarks in the localizer for the desired CT scan range adjustment needs to be considered. The effective dose of a head, chest, and abdomen-pelvis localizer radiograph with standard factory settings and user-optimized settings was determined using Monte Carlo simulations. CT examinations of an anthropomorphic phantom were performed using multiple sets of acquisition parameters for the localizer radiograph and the AEC for the subsequent helical CT scan. Anatomical landmarks were defined to assess the image quality of the localizer. CTDI{sub vol} and effective mAs per slice of the helical CT scan were recorded to examine the impact of localizer settings on a helical CT scan. The dose of the localizer radiograph could be decreased by more than 90% while the image quality remained sufficient when selecting the lowest available settings (80 kVp, 20 mA, pa tube position). The tube position during localizer acquisition had a greater impact on the AEC than the reduction of tube voltage and tube current. Except for the use of a pa tube position, all changes of acquisition parameters for the localizer resulted in a decreased total radiation exposure. A dose reduction of CT localizer radiograph is necessary and possible. In the examined CT system there was no negative impact on the modulated helical CT scan when the lowest tube voltage and tube current were used for the localizer.

  20. Preoperative staging of non-small cell lung cancer: prospective comparison of PET/MR and PET/CT.

    Science.gov (United States)

    Lee, Sang Min; Goo, Jin Mo; Park, Chang Min; Yoon, Soon Ho; Paeng, Jin Chul; Cheon, Gi Jeong; Kim, Young Tae; Park, Young Sik

    2016-11-01

    To prospectively compare the accuracies of PET/MR and PET/CT in the preoperative staging of non-small cell lung cancer (NSCLC). Institutional review board approval and patients' informed consents were obtained. 45 patients with proven or radiologically suspected lung cancer which appeared to be resectable on CT were enrolled. PET/MR was performed for the preoperative staging of NSCLC followed by PET/CT without contrast enhancement on the same day. Dedicated MR images including diffusion weighted images were obtained. Readers assessed PET/MR and PET/CT with contrast-enhanced CT. Accuracies of PET/MR and PET/CT for NSCLC staging were compared. Primary tumour stages (n = 40) were correctly diagnosed in 32 patients (80.0 %) on PET/MR and in 32 patients (80.0 %) on PET/CT (P = 1.0). Node stages (n = 42) were correctly determined in 24 patients (57.1 %) on PET/MR and in 22 patients (52.4 %) on PET/CT (P = 0.683). Metastatic lesions in the brain, bone, liver, and pleura were detected in 6 patients (13.3 %). PET/MR missed one patient with pleural metastasis while PET/CT missed one patient with solitary brain metastasis and two patients with pleural metastases (P = 0.480). This study demonstrated that PET/MR in combination with contrast-enhanced CT was comparable to PET/CT in the preoperative staging of NSCLC while reducing radiation exposure. • PET/MR can be comparable to PET/CT for preoperative NSCLC staging. • PET/MR and PET/CT show excellent correlation in measuring SUVmax of primary lesions. • Using PET/MR, estimated radiation dose can decrease by 31.1 % compared with PET/CT.

  1. SU-F-T-253: Volumetric Comparison Between 4D CT Amplitude and Phase Binning Mode

    Energy Technology Data Exchange (ETDEWEB)

    Yang, G; Ma, R; Reyngold, M [Memorial Sloan-Kettering Cancer Center, Commack, NY (United States); Li, X; Xiong, W; Gewanter, R [Memorial Sloan-Kettering Cancer Center, Rockville Center, NY (United States); Yorke, E; Mageras, G; Wu, A; Deasy, J; Hunt, M [Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Tang, X [Memorial Sloan-Kettering Cancer Center, West Harrison, NY (United States); Chan, M [Memorial Sloan-Kettering Cancer Center, Basking Ridge, NJ (United States)

    2016-06-15

    Purpose: Motion artifact in 4DCT images can affect radiation treatment quality. To identify the most robust and accurate binning method, we compare the volume difference between targets delineated on amplitude and phase binned 4DCT scans. Methods: Varian RPM system and CT scanner were used to acquire 4DCTs of a Quasar phantom with embedded cubic and spherical objects having superior-inferior motion. Eight patients’ respiration waveforms were used to drive the phantom. The 4DCT scan was reconstructed into 10 phase and 10 amplitude bins (2 mm slices). A scan of the static phantom was also acquired. For each waveform, sphere and cube volumes were generated automatically on each phase using HU thresholding. Phase (amplitude) ITVs were the union of object volumes over all phase (amplitude) binned images. The sphere and cube volumes measured in the static phantom scan were V{sub sphere}=4.19cc and V{sub cube}=27.0cc. Volume difference (VD) and dice similarity coefficient (DSC) of the ITVs, and mean volume error (MVE) defined as the average target volume percentage difference between each phase image and the static image, were used to evaluate the performance of amplitude and phase binning. Results: Averaged over the eight breathing traces, the VD and DSC of the internal target volume (ITV) between amplitude and phase binning were 3.4%±3.2% (mean ± std) and 95.9%±2.1% for sphere; 2.1%±3.3% and 98.0% ±1.5% for cube, respectively.For all waveforms, the average sphere MVE of amplitude and phase binning was 6.5% ± 5.0% and 8.2%±6.3%, respectively; and the average cube MVE of amplitude and phase binning was 5.7%±3.5%and 12.9%±8.9%, respectively. Conclusion: ITV volume and spatial overlap as assessed by VD and DSC are similar between amplitude and phase binning. Compared to phase binning, amplitude binning results in lower MVE suggesting it is less susceptible to motion artifact.

  2. Estimation of lung motion fields in 4D CT data by variational non-linear intensity-based registration: A comparison and evaluation study.

    Science.gov (United States)

    Werner, René; Schmidt-Richberg, Alexander; Handels, Heinz; Ehrhardt, Jan

    2014-08-07

    Accurate and robust estimation of motion fields in respiration-correlated CT (4D CT) images, usually performed by non-linear registration of the temporal CT frames, is a precondition for the analysis of patient-specific breathing dynamics and subsequent image-supported diagnostics and treatment planning. In this work, we present a comprehensive comparison and evaluation study of non-linear registration variants applied to the task of lung motion estimation in thoracic 4D CT data. In contrast to existing multi-institutional comparison studies (e.g. MIDRAS and EMPIRE10), we focus on the specific but common class of variational intensity-based non-parametric registration and analyze the impact of the different main building blocks of the underlying optimization problem: the distance measure to be minimized, the regularization approach and the transformation space considered during optimization. In total, 90 different combinations of building block instances are compared. Evaluated on proprietary and publicly accessible 4D CT images, landmark-based registration errors (TRE) between 1.14 and 1.20 mm for the most accurate registration variants demonstrate competitive performance of the applied general registration framework compared to other state-of-the-art approaches for lung CT registration. Although some specific trends can be observed, effects of interchanging individual instances of the building blocks on the TRE are in general rather small (no single outstanding registration variant existing); the same level of accuracy is, however, associated with significantly different degrees of motion field smoothness and computational demands. Consequently, the building block combination of choice will depend on application-specific requirements on motion field characteristics.

  3. Magnetic Helicity and Planetary Dynamos

    Science.gov (United States)

    Shebalin, John V.

    2012-01-01

    A model planetary dynamo based on the Boussinesq approximation along with homogeneous boundary conditions is considered. A statistical theory describing a large-scale MHD dynamo is found, in which magnetic helicity is the critical parameter

  4. Helicity multiplexed broadband metasurface holograms

    Science.gov (United States)

    Wen, Dandan; Yue, Fuyong; Li, Guixin; Zheng, Guoxing; Chan, Kinlong; Chen, Shumei; Chen, Ming; Li, King Fai; Wong, Polis Wing Han; Cheah, Kok Wai; Yue Bun Pun, Edwin; Zhang, Shuang; Chen, Xianzhong

    2015-09-01

    Metasurfaces are engineered interfaces that contain a thin layer of plasmonic or dielectric nanostructures capable of manipulating light in a desirable manner. Advances in metasurfaces have led to various practical applications ranging from lensing to holography. Metasurface holograms that can be switched by the polarization state of incident light have been demonstrated for achieving polarization multiplexed functionalities. However, practical application of these devices has been limited by their capability for achieving high efficiency and high image quality. Here we experimentally demonstrate a helicity multiplexed metasurface hologram with high efficiency and good image fidelity over a broad range of frequencies. The metasurface hologram features the combination of two sets of hologram patterns operating with opposite incident helicities. Two symmetrically distributed off-axis images are interchangeable by controlling the helicity of the input light. The demonstrated helicity multiplexed metasurface hologram with its high performance opens avenues for future applications with functionality switchable optical devices.

  5. Helicity multiplexed broadband metasurface holograms.

    Science.gov (United States)

    Wen, Dandan; Yue, Fuyong; Li, Guixin; Zheng, Guoxing; Chan, Kinlong; Chen, Shumei; Chen, Ming; Li, King Fai; Wong, Polis Wing Han; Cheah, Kok Wai; Pun, Edwin Yue Bun; Zhang, Shuang; Chen, Xianzhong

    2015-09-10

    Metasurfaces are engineered interfaces that contain a thin layer of plasmonic or dielectric nanostructures capable of manipulating light in a desirable manner. Advances in metasurfaces have led to various practical applications ranging from lensing to holography. Metasurface holograms that can be switched by the polarization state of incident light have been demonstrated for achieving polarization multiplexed functionalities. However, practical application of these devices has been limited by their capability for achieving high efficiency and high image quality. Here we experimentally demonstrate a helicity multiplexed metasurface hologram with high efficiency and good image fidelity over a broad range of frequencies. The metasurface hologram features the combination of two sets of hologram patterns operating with opposite incident helicities. Two symmetrically distributed off-axis images are interchangeable by controlling the helicity of the input light. The demonstrated helicity multiplexed metasurface hologram with its high performance opens avenues for future applications with functionality switchable optical devices.

  6. Comparison of {sup 18}F-FACBC and {sup 11}C-choline PET/CT in patients with radically treated prostate cancer and biochemical relapse: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Nanni, Cristina; Boschi, Stefano [Azienda Ospedaliero-Universitaria di Bologna Policlinico S.Orsola-Malpighi, OU Nuclear Medicine, Bologna (Italy); Schiavina, Riccardo; Ambrosini, Valentina; Brunocilla, Eugenio; Martorana, Giuseppe; Fanti, Stefano [Azienda Ospedaliero-Universitaria di Bologna Policlinico S.Orsola-Malpighi, OU Urology, Bologna (Italy); Pettinato, Cinzia [Azienda Ospedaliero-Universitaria di Bologna Policlinico S.Orsola-Malpighi, OU Medical Physics, Bologna (Italy)

    2013-07-15

    We assessed the rate of detection rate of recurrent prostate cancer by PET/CT using anti-3-{sup 18}F-FACBC, a new synthetic amino acid, in comparison to that using {sup 11}C-choline as part of an ongoing prospective single-centre study. Included in the study were 15 patients with biochemical relapse after initial radical treatment of prostate cancer. All the patients underwent anti-3-{sup 18}F-FACBC PET/CT and {sup 11}C-choline PET/CT within a 7-day period. The detection rates using the two compounds were determined and the target-to-background ratios (TBR) of each lesion are reported. No adverse reactions to anti-3-{sup 18}F-FACBC PET/CT were noted. On a patient basis, {sup 11}C-choline PET/CT was positive in 3 patients and negative in 12 (detection rate 20 %), and anti-3-{sup 18}F-FACBC PET/CT was positive in 6 patients and negative in 9 (detection rate 40 %). On a lesion basis, {sup 11}C-choline detected 6 lesions (4 bone, 1 lymph node, 1 local relapse), and anti-3-{sup 18}F-FACBC detected 11 lesions (5 bone, 5 lymph node, 1 local relapse). All {sup 11}C-choline-positive lesions were also identified by anti-3-{sup 18}F-FACBC PET/CT. The TBR of anti-3-{sup 18}F-FACBC was greater than that of {sup 11}C-choline in 8/11 lesions, as were image quality and contrast. Our preliminary results indicate that anti-3-{sup 18}F-FACBC may be superior to {sup 11}C-choline for the identification of disease recurrence in the setting of biochemical failure. Further studies are required to assess efficacy of anti-3-{sup 18}F-FACBC in a larger series of prostate cancer patients. (orig.)

  7. Coronary CT angiography characteristics of OCT-defined thin-cap fibroatheroma: a section-to-section comparison study.

    Science.gov (United States)

    Yang, Dong Hyun; Kang, Soo-Jin; Koo, Hyun Jung; Chang, Mineok; Kang, Joon-Won; Lim, Tae-Hwan; Baek, Seunghee; Han, Seungbong; Lee, Pil Hyung; Roh, Jae-Hyung; Ahn, Jung-Min; Park, Duk-Woo; Lee, Seung-Whan; Lee, Cheol Whan; Park, Seong-Wook; Park, Seung-Jung; Mintz, Gary S; Kim, Young-Hak

    2018-02-01

    To evaluate whether plaque characteristics as assessed by coronary computed tomography angiography (CCTA) were associated with the presence of a thin-cap fibroatheroma (TCFA)-a precursor of plaque rupture-defined by optical coherence tomography (OCT) in a section-to-section-level comparison. From 28 symptomatic patients, 31 coronary lesions were evaluated on 727 cross-sections co-registered by both CCTA and OCT. CCTA plaque characteristics included low attenuation plaque (LAP, OCT, presence of TCFA, lumen area and arc of lipid were determined. OCT revealed a TCFA in 69 (9.4%) sections from 19 (61.2 %) lesions. In per-section analysis, OCT-TCFA showed higher frequency of CCTA-detected LAP (58.0% vs. 18.5%), NRS (31.9% vs. 8.8%) and PR (68.1% vs. 48.0%) and greater plaque burden (70.6% vs. 61.9%) as compared to sections without OCT-TCFA (all p OCT-TCFA. CCTA-measured lumen area correlated well with OCT-measured lumen area (R = 0.859, limits of agreement -0.5 ± 3.7 mm 2 ). LAP and NRS in CCTA were associated with the presence of OCT-defined TCFA in a section-to-section comparison. • CT-defined LAP and NRS were associated with OCT-defined TCFA • OCT-TCFA showed higher frequency of LAP, NRS, PR and greater plaque burden • Non-calcified plaque area was correlated with OCT-measured lipid arc.

  8. Single- and dual-energy CT of the abdomen: comparison of radiation dose and image quality of 2nd and 3rd generation dual-source CT.

    Science.gov (United States)

    Wichmann, Julian L; Hardie, Andrew D; Schoepf, U Joseph; Felmly, Lloyd M; Perry, Jonathan D; Varga-Szemes, Akos; Mangold, Stefanie; Caruso, Damiano; Canstein, Christian; Vogl, Thomas J; De Cecco, Carlo N

    2017-02-01

    To compare single-energy (SECT) and dual-energy (DECT) abdominal CT examinations in matched patient cohorts regarding differences in radiation dose and image quality performed with second- and third-generation dual-source CT (DSCT). We retrospectively analysed 200 patients (100 male, 100 female; mean age 61.2 ± 13.5 years, mean body mass index 27.5 ± 3.8 kg/m 2 ) equally divided into four groups matched by gender and body mass index, who had undergone portal venous phase abdominal CT with second-generation (group A, 120-kV-SECT; group B, 80/140-kV-DECT) and third-generation DSCT (group C, 100-kV-SECT; group D, 90/150-kV-DECT). The radiation dose was normalised for 40-cm scan length. Dose-independent figure-of-merit (FOM) contrast-to-noise ratios (CNRs) were calculated for various organs and vessels. Subjective overall image quality and reader confidence were assessed. The effective normalised radiation dose was significantly lower (P efficiency. • Dual-source CT (DSCT) allows for single- and dual-energy image acquisition. • Dual-energy acquisition does not increase the radiation dose in abdominal DSCT. • Third-generation DSCT shows improved dose efficiency compared to second-generation DSCT. • Dose-independent figure-of-merit image contrast was highest with third-generation dual-energy DSCT. • Third-generation DSCT shows improved dose efficiency for SECT and DECT.

  9. Risk factors indicating the need for cranial CT scans in elderly patients with head trauma: an Austrian trial and comparison with the Canadian CT Head Rule.

    Science.gov (United States)

    Wolf, Harald; Machold, Wolfgang; Frantal, Sophie; Kecht, Mathias; Pajenda, Gholam; Leitgeb, Johannes; Widhalm, Harald; Hajdu, Stefan; Sarahrudi, Kambiz

    2014-02-01

    This study presents newly defined risk factors for detecting clinically important brain injury requiring neurosurgical intervention and intensive care, and compares it with the Canadian CT Head Rule (CCHR). This prospective cohort study was conducted in a single Austrian Level-I trauma center and enrolled a consecutive sample of mildly head-injured adults who presented to the emergency department with witnessed loss of consciousness, disorientation, or amnesia, and a Glasgow Coma Scale (GCS) score of 13-15. The studied population consisted of a large number of elderly patients living in Vienna. The aim of the study was to investigate risk factors that help to predict the need for immediate cranial CT in patients with mild head trauma. Among the 12,786 enrolled patients, 1307 received a cranial CT scan. Four hundred eighty-nine patients (37.4%) with a mean age of 63.9 ± 22.8 years had evidence of an acute traumatic intracranial lesion on CT. Three patients ( 65 years, loss of consciousness, nausea or vomiting, hypocoagulation, dementia or a history of ischemic stroke, anisocoria, skull fracture, and development of a focal neurological deficit. Patients requiring neurosurgical intervention were detected with a sensitivity of 90% and a specificity of 67% by using the authors' analysis. In contrast, the use of the CCHR in these patients detected the need for neurosurgical intervention with a sensitivity of only 80% and a specificity of 72%. The use of the suggested parameters proved to be superior in the detection of high-risk patients who sustained a mild head trauma compared with the CCHR rules. Further validation of these results in a multicenter setting is needed. Clinical trial registration no.: NCT00451789 ( ClinicalTrials.gov .).

  10. Comparison of CT versus MRI measurements of transverse atlantal ligament integrity in craniovertebral junction injuries. Part 2: A new CT-based alternative for assessing transverse ligament integrity.

    Science.gov (United States)

    Perez-Orribo, Luis; Kalb, Samuel; Snyder, Laura A; Hsu, Forrest; Malhotra, Devika; Lefevre, Richard D; Elhadi, Ali M; Newcomb, Anna G U S; Theodore, Nicholas; Crawford, Neil R

    2016-06-01

    OBJECTIVE The rule of Spence is inaccurate for assessing integrity of the transverse atlantal ligament (TAL). Because CT is quick and easy to perform at most trauma centers, the authors propose a novel sequence of obtaining 2 CT scans to improve the diagnosis of TAL impairment. The sensitivity of a new CT-based method for diagnosing a TAL injury in a cadaveric model was assessed. METHODS Ten human cadaveric occipitocervical specimens were mounted horizontally in a supine posture with wooden inserts attached to the back of the skull to maintain a neutral or flexed (10°) posture. Specimens were scanned in neutral and flexed postures in a total of 4 conditions (3 conditions in each specimen): 1) intact (n = 10); either 2A) after a simulated Jefferson fracture with an intact TAL (n = 5) or 2B) after a TAL disruption with no Jefferson fracture (n = 5); and 3) after TAL disruption and a simulated Jefferson fracture (n = 10). The atlantodental interval (ADI) and cross-sectional canal area were measured. RESULTS From the neutral to the flexed posture, ADI increased an average of 2.5% in intact spines, 6.25% after a Jefferson fracture without TAL disruption, 34% after a TAL disruption without fracture, and 25% after TAL disruption with fracture. The increase in ADI was significant with both TAL disruption and TAL disruption and fracture (p 0.6). Changes in spinal canal area were not significant (p > 0.70). CONCLUSIONS This novel method was more sensitive than the rule of Spence for evaluating the integrity of the TAL on CT and does not increase the risk of further neurological damage.

  11. CT evaluation of native acetabular orientation and localization: sex-specific data comparison on 336 hip joints.

    Science.gov (United States)

    Tohtz, Stephan W; Sassy, Danny; Matziolis, Georg; Preininger, Bernd; Perka, Carsten; Hasart, Olaf

    2010-01-01

    The reorientation of the acetabular component in total hip replacement is currently carried out under consideration of the safe zone, respecting the best possible range of motion and is influenced by wear debris of different bearings. Is the preferred orientation a reconstruction of the native anatomy and are there sex-specific differences? On the basis of 168 CT datasets (72 women, 96 men) 336 native hip joints were analysed. The abduction and anteversion of the acetabulum as well as the location of the hip center were detected. As a reference the anterior pelvic plane was used. The 144 female hip joints showed a mean abduction of 53.0 degrees (SD 6.14 degrees ) and an anteversion of 24.63 degrees (SD 6.61 degrees ). The 192 male hip joints showed an abduction of 53.58 degrees (SD 6.68 degrees ) and an anteversion of 21.31 degrees (SD 6.17 degrees ). Significant differences were observed on comparison between the sexes in relation to the anteversion and the location of the hip center. Likewise, there was a significant correlation between the position of the hip center and the degree of anteversion. In total hip arthroplasty a reconstruction of the native acetabular orientation is not possible, gender specific characteristics should be considered.

  12. Diagnostic performance of FDG-PET/MRI and WB-DW-MRI in the evaluation of lymphoma: a prospective comparison to standard FDG-PET/CT.

    Science.gov (United States)

    Herrmann, Ken; Queiroz, Marcelo; Huellner, Martin W; de Galiza Barbosa, Felipe; Buck, Andreas; Schaefer, Niklaus; Stolzman, Paul; Veit-Haibach, Patrick

    2015-12-23

    Use of FDG-PET/CT for staging and restaging of lymphoma patients is widely incorporated into current practice guidelines. Our aim was to prospectively evaluate the diagnostic performance of FDG-PET/MRI and WB-DW-MRI compared with FDG-FDG-PET/CT using a tri-modality PET/CT-MRI system. From 04/12 to 01/14, a total of 82 FDG-PET/CT examinations including an additional scientific MRI on a tri-modality setup were performed in 61 patients. FDG-PET/CT, FDG-PET/MRI, and WB-DW-MRI were independently analyzed. A lesion with a mean ADC below a threshold of 1.2 × 10(-3) mm(2)/s was defined as positive for restricted diffusion. FDG-PET/CT and FDG-PET/MRI were evaluated for the detection of lesions corresponding to lymphoma manifestations according to the German Hodgkin Study Group. Imaging findings were validated by biopsy (n = 21), by follow-up imaging comprising CT, FDG-PET/CT, and/or FDG-PET/MRI (n = 32), or clinically (n = 25) (mean follow-up: 9.1 months). FDG-PET/MRI and FDG-PET/CT accurately detected 188 lesions in 27 patients. Another 54 examinations in 35 patients were negative. WB-DW-MRI detected 524 lesions, of which 125 (66.5% of the aforementioned 188 lesions) were true positive. Among the 188 lesions positive for lymphoma, FDG-PET/MRI detected all 170 instances of nodal disease and also all 18 extranodal lymphoma manifestations; by comparison, WB-DW-MRI characterized 115 (67.6%) and 10 (55.6%) lesions as positive for nodal and extranodal disease, respectively. FDG-PET/MRI was superior to WB-DW-MRI in detecting lymphoma manifestations in patients included for staging (113 vs. 73), for restaging (75 vs. 52), for evaluation of high- (127 vs. 81) and low-grade lymphomas (61 vs. 46), and for definition of Ann Arbor stage (WB-DW-MRI resulted in upstaging in 60 cases, including 45 patients free of disease, and downstaging in 4). Our results indicate that FDG-PET/CT and FDG-PET/MRI probably have a similar performance in the clinical work-up of lymphomas. The performance

  13. A comparison of preplan MRI and preplan CT-based prostate volume with intraoperative ultrasound-based prostate volume in real-time permanent brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hye Li; Kim, Ja Young; Lee, Bo Mi; Chang, Sei Kyung; Ko, Seung Young; Kim, Sung Jun; Park, Dong Soo; Shin, Hyun Soo [CHA Bundang Medical Center, CHA University, Seougnam (Korea, Republic of)

    2011-09-15

    The present study compared the difference between intraoperative transrectal ultrasound (iTRUS)-based prostate volume and preplan computed tomography (CT), preplan magnetic resonance imaging (MRI)-based prostate volume to estimate the number of seeds needed for appropriate dose coverage in permanent brachytherapy for prostate cancer. Between March 2007 and March 2011, among 112 patients who underwent permanent brachytherapy with 125I, 60 image scans of 56 patients who underwent preplan CT (pCT) or preplan MRI (pMRI) within 2 months before brachytherapy were retrospectively reviewed. Twenty-four cases among 30 cases with pCT and 26 cases among 30 cases with pMRI received neoadjuvant hormone therapy (NHT). In 34 cases, NHT started after acquisition of preplan image. The median duration of NHT after preplan image acquisition was 17 and 21 days for cases with pCT and pMRI, respectively. The prostate volume calculated by different modalities was compared. And retrospective planning with iTRUS image was performed to estimate the number of 125I seed required to obtain recommended dose distribution according to prostate volume. The mean difference in prostate volume was 9.05 mL between the pCT and iTRUS and 6.84 mL between the pMRI and iTRUS. The prostate volume was roughly overestimated by 1.36 times with pCT and by 1.33 times with pMRI. For 34 cases which received NHT after image acquisition, the prostate volume was roughly overestimated by 1.45 times with pCT and by 1.37 times with pMRI. A statistically significant difference was found between preplan image-based volume and iTRUS-based volume (p<0.001). The median number of wasted seeds is approximately 13, when the pCT or pMRI volume was accepted without modification to assess the required number of seeds for brachytherapy. pCT-based volume and pMRI-based volume tended to overestimate prostate volume in comparison to iTRUS-based volume. To reduce wasted seeds and cost of the brachytherapy, we should take the volume

  14. TU-C-12A-11: Comparisons Between Cu-ATSM PET and DCE-CT Kinetic Parameters in Canine Sinonasal Tumors

    Energy Technology Data Exchange (ETDEWEB)

    La Fontaine, M; Bradshaw, T [University of Wisconsin, Madison, Wisconsin (United States); Kubicek, L [University of Florida, Gainesville, Florida (United States); Forrest, L [University of Wisconsin-Madison, Madison, Wisconsin (United States); Jeraj, R [University of Wisconsin, Madison, WI (United States)

    2014-06-15

    Purpose: Regions of poor perfusion within tumors may be associated with higher hypoxic levels. This study aimed to test this hypothesis by comparing measurements of hypoxia from Cu-ATSM PET to vasculature kinetic parameters from DCE-CT kinetic analysis. Methods: Ten canine patients with sinonasal tumors received one Cu-ATSM PET/CT scan and three DCE-CT scans prior to treatment. Cu-ATSM PET/CT and DCE-CT scans were registered and resampled to matching voxel dimensions. Kinetic analysis was performed on DCE-CT scans and for each patient, the resulting kinetic parameter values from the three DCE-CT scans were averaged together. Cu-ATSM SUVs were spatially correlated (r{sub spatial}) on a voxel-to-voxel basis against the following DCE-CT kinetic parameters: transit time (t{sub 1}), blood flow (F), vasculature fraction (v{sub 1}), and permeability (PS). In addition, whole-tumor comparisons were performed by correlating (r{sub ROI}) the mean Cu-ATSM SUV (SUV{sub mean}) with median kinetic parameter values. Results: The spatial correlations (r{sub spatial}) were poor and ranged from -0.04 to 0.21 for all kinetic parameters. These low spatial correlations may be due to high variability in the DCE-CT kinetic parameter voxel values between scans. In our hypothesis, t{sub 1} was expected to have a positive correlation, while F was expected to have a negative correlation to hypoxia. However, in wholetumor analysis the opposite was found for both t{sub 1} (r{sub ROI} = -0.25) and F (r{sub ROI} = 0.56). PS and v{sub 1} may depict angiogenic responses to hypoxia and found positive correlations to Cu-ATSM SUV for PS (r{sub ROI} = 0.41), and v{sub 1} (r{sub ROI} = 0.57). Conclusion: Low spatial correlations were found between Cu-ATSM uptake and DCE-CT vasculature parameters, implying that poor perfusion is not associated with higher hypoxic regions. Across patients, the most hypoxic tumors tended to have higher blood flow values, which is contrary to our initial hypothesis. Funding

  15. BAY 1075553 PET-CT for Staging and Restaging Prostate Cancer Patients: Comparison with [18F] Fluorocholine PET-CT (Phase I Study).

    Science.gov (United States)

    Beheshti, Mohsen; Kunit, Thomas; Haim, Silke; Zakavi, Rasoul; Schiller, Christian; Stephens, Andrew; Dinkelborg, Ludger; Langsteger, Werner; Loidl, Wolfgang

    2015-06-01

    (2RS,4S)-2-[(18)F]Fluoro-4-phosphonomethyl-pentanedioic acid (BAY1075553) shows increased uptake in prostate cancer cells. We compared the diagnostic potential of positron emission tomography (PET)-X-ray computed tomography (CT) imaging using BAY1075553 versus [(18)F]f luorocholine (FCH) PET-CT. Twelve prostate cancer patients (nine staging, three re-staging) were included. The mean prostate-specific antigen in the primary staging and re-staging groups was 21.5 ± 12 and 73.6 ± 33 ng/ml, respectively. Gleason score ranged from 5-9. In nine patients imaged for pre-operative staging, the median Gleason score was 8 (range, 7-9). PET acquisition started with dynamic PET images in the pelvic region followed by static whole-body acquisition. The patients were monitored for 5-8 days afterward for adverse events. There were no relevant changes in laboratory values or physical examination. Urinary bladder wall received the largest dose equivalent 0.12 mSv/MBq. The whole-body mean effective dose was 0.015 mSv/MBq. There was a significant correlation between detected prostatic lesions by the two imaging modalities (Kappa = 0.356, P prostate cancer. FCH PET-CT results were superior, however, with respect to detecting LN and bone marrow metastases.

  16. [Direct CT-arthrography versus direct MR-arthrography in chronic shoulder instability: comparison of modalities after the introduction of multidetector-CT technology].

    Science.gov (United States)

    Bitzer, M; Nasko, M; Krackhardt, T; Schick, F; Schöber, W; Wiskirchen, J; Morgalla, M; Weise, K; Claussen, C

    2004-12-01

    To evaluate the diagnostic accuracy of direct multidetector CT arthrography (CTA) and direct MR arthrography (MRA) in patients suffering from chronic shoulder instability. Twenty-nine patients suffering from chronic shoulder instability were included into a prospective study. In all cases, the indication for direct CTA and arthroscopy was set by the orthopedic surgeon. Prior to the imaging procedures, 10 to 20 ml of a special combination of contrast media (including saline, Isovist(R) and Magnevist(R) in a relation of 125 : 125 : 1) was injected into the joint under sterile conditions. First, CTA was performed with a multidetector CT, with images reconstructed in the axial, semi-coronal and semi-sagittal planes. Thereafter, MRA was performed. Axial images were obtained using a T1-weighted, fat-saturated spin echo sequence and semi-coronal images using a T1-weighted FLASH-3D GRE sequence. The results of CTA and MTA were compared with results obtained from arthroscopy or arthrotomy. MRA was superior to CTA in the detection of labral lesions. The sensitivity of MRA was 96 % and the specificity 96 %, compared to a sensitivity of 76 % (p < 0.05) and specificity of 92 % for CTA. Both methods showed the same effectiveness concerning the assessment of capsule distension (sensitivity for both techniques: 91 %). MRA seems to be superior to CTA in the diagnostic workup of chronic shoulder instability even when using a multidetector CT technique.

  17. Reference standard and statistical model for intersite and temporal comparisons of CT attenuation in a multicenter quantitative lung study.

    Science.gov (United States)

    Sieren, J P; Newell, J D; Judy, P F; Lynch, D A; Chan, K S; Guo, J; Hoffman, E A

    2012-09-01

    The purpose of this study was to detect and analyze anomalies between a large number of computed tomography (CT) scanners, tracked over time, utilized to collect human pulmonary CT data for a national multicenter study: chronic obstructive pulmonary disease genetic epidemiology study (COPDGene). A custom designed CT reference standard "Test Object" has been developed to evaluate the relevant differences in CT attenuation between CT scanners in COPDGene. The materials used in the Test Object to assess CT scanner accuracy and precision included lung equivalent foam (-856 HU), internal air (-1000 HU), water (0 HU), and acrylic (120 HU). Nineteen examples of the Test Object were manufactured. Initially, all Test Objects were scanned on the same CT scanner before the Test Objects were sent to the 20 specific sites and 42 individual CT scanners that were used in the study. The Test Objects were scanned over 17 months while the COPDGene study continued to recruit subjects. A mixed linear effect statistical analysis of the CT scans on the 19 Test Objects was performed. The statistical model reflected influence of reconstruction kernels, tube current, individual Test Objects, CT scanner models, and temporal consistency on CT attenuation. Depending on the Test Object material, there were significant differences between reconstruction kernels, tube current, individual Test Objects, CT scanner models, and temporal consistency. The two Test Object materials of most interest were lung equivalent foam and internal air. With lung equivalent foam, there were significant (p reference standard (-852.5 ± 1.4). Comparing lung equivalent foam attenuation there were also significant differences between CT scanner models (p reference scans of the 19 Test Objects. For internal air, significant (p reference standard. There were significant differences between CT models (p reference scans of the 19 Test Objects. Differences, across scanners, between external air and internal air measures in

  18. Helicity of Solar Active Regions from a Dynamo Model Piyali ...

    Indian Academy of Sciences (India)

    above need not be mutually exclusive: both may be simultaneously operative. A careful comparison between observational data and detailed theoretical models will be needed to ascertain the relative importance of these two effects. We present here calculations of helicity based on our two-dimensional kinematic.

  19. Helical computed tomography in the diagnosis of pulmonary thromboembolism: comparison with pulmonary arteriography; La tomografia compuatarizada helicoidal en el diagnostico del tromboembolismo pulmanar. Estudio comparativo con la arteriografia pulmonar

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, Y.; Caniego, J. L.; Caballero, P.; Olivera, M. J.; Friera, A.; Gallego, C.; Tarrago, D. [Hospital de la Princesa. Madrid (Spain); Alvarez-Sala, R. [Hospital La Paz. Madrid (Spain)

    2000-07-01

    To assess the utility of helical computed tomography in the diagnosis of pulmonary thromboembolism, comparing it with that of pulmonary arteriography. Thirty patients with clinical signs of pulmonary thromboembolism underwent both helical computed tomography with intravenous contrast and pulmonary arteriography within an interval of no more than 24 hours. Each procedure was subjected to independent, blinded evaluation to establish the absence or presence of thromboembolism and its location. Helical computed tomography correctly identified 12 of 14 cases of pulmonary thromboembolism (sensitivity: 85.7%) and 15 of 16 in which it was not present (specificity: 93.7%). The positive and negative predictive values were 92.3% and 88.2%, respectively. The diagnostic reliability was 90%. All the central embolisms were correctly diagnosed; the two false positives corresponded to embolisms located in a segment and sub segment, respectively. Helical computed tomography is a reliable diagnostic method for the detection and exclusion of pulmonary thromboembolism. (Author) 21 refs.

  20. Optical helices and spiral interference fringes

    Science.gov (United States)

    Harris, M.; Hill, C. A.; Vaughan, J. M.

    1994-03-01

    Very pure optical helices have been generated in an argon ion laser of low Fresnel number. The beam character, with continuous cophasal surface of helical form, is clearly demonstrated by spiral interference fringes produced in a novel interferometric arrangement. In addition to single-start helices the multistart fringe patterns establish both two-start and three-start helices (of pitch two and three wavelengths, respectively), and also the state of helicity (i.e. rotational hand) of the beams.

  1. Adenosine-stress low-dose single-scan CT myocardial perfusion imaging using a 128-slice dual-source CT: a comparison with fractional flow reserve.

    Science.gov (United States)

    Choo, Ki Seok; Hwangbo, Lee; Kim, June Hong; Park, Yong Hyun; Kim, Jeong Su; Kim, Jun; Chun, Kook Jin; Jeong, Dong Wook; Lim, Soo Jin

    2013-05-01

    Coronary CT angiography (CCTA) allows accurate evaluation of coronary artery stenosis but has limitations in information on hemodynamic significance of stenotic lesions. To determine the feasibility of adenosine-stress low-dose single-scan CT myocardial perfusion imaging (MPI) using a 128-slice dual-source CT scanner for the diagnosis of hemodynamically significant coronary artery stenosis as defined by fractional flow reserve (FFR). This study was proved by the Institutional Review Board and informed consent was obtained from the patients before enrollment in the study. Ninety-seven patients with chest pain and low-to-intermediate pretest probability of coronary artery disease were prospectively enrolled. Adenosine-stress CCTA using ECG-correlated maximum tube current modulation (Mindose(®)) with 128-slice dual-source CT was performed in all 97 patients. In 37 patients (38.1%; 28 men, nine women; mean age, 61.7 ± 20.5 years; mean heart rate, 74.6 ± 2.8 bpm) with significant stenosis at CCTA (lumen diameter reduction >50%), FFR was performed after CCTA, as a reference standard for the evaluation of myocardial perfusion. FFR value ≤0.75 was considered as positive. CTMPI and CCTA were read by two experienced radiologists with consensus, respectively. The effective radiation dose of adenosine-stress single-scan CTMPI was 4.63 ± 2.57 mSv. Compared with FFR, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for identifying significant coronary stenoses were 93.1%, 82.7%, 75.0%, and 95.6%, respectively, on CCTA and 93.1%, 90.3%, 84.4%, and 95.9%, respectively, on CTMPI. On combined CCTA and CTMPI, sensitivity, specificity, PPV, and NPV were 93.1%, 94.2%, 90.0%, and 96.0%, respectively. Adenosine-stress low-dose single scan CTMPI using a 128-slice dual-source CT can provide complementary information on the hemodynamical significance of coronary artery stenosis as well as anatomical information of coronary arteries.

  2. CT findings of TB in diabetic and non-diabetic patients: A comparison before and after anti-tuberculous therapy

    Directory of Open Access Journals (Sweden)

    Hao Wu

    2016-03-01

    Conclusion: CT findings of tuberculosis in diabetic patients are different from those in non-diabetic patients, with a higher occurrence of non-segmental distribution and multiple cavities within a tuberculous lesion. By follow-up re-examination, diabetic patients show a slower and unobvious therapeutic response on CT scans compared to non-diabetic patients. CT can provide important information for the diagnosis and management of TB in diabetic and non-diabetic patients.

  3. Dynamic comparison of PET imaging performance between state-of-the-art ToF-PET/CT and ToF-PET/MR scanners

    Energy Technology Data Exchange (ETDEWEB)

    Delso, Gaspar; Deller, Tim; Khalighi, Mehdi [GE Healthcare (Switzerland); Veit-Haibach, Patrick; Schulthess, Gustav von [University Hospital of Zurich (Switzerland)

    2014-07-29

    The goal of the present work was to determine the potential for dose reduction in a new clinical ToF-PET/MR scanner. This was achieved by means of long dynamic phantom acquisitions designed to provide a fair comparison of image quality and lesion detectability, as a function of activity, between the new PET/MR system and a state-of-the art PET/CT.

  4. Efficacy and safety of CT-P13 (biosimilar infliximab) in patients with rheumatoid arthritis: comparison between switching from reference infliximab to CT-P13 and continuing CT-P13 in the PLANETRA extension study.

    Science.gov (United States)

    Yoo, Dae Hyun; Prodanovic, Nenad; Jaworski, Janusz; Miranda, Pedro; Ramiterre, Edgar; Lanzon, Allan; Baranauskaite, Asta; Wiland, Piotr; Abud-Mendoza, Carlos; Oparanov, Boycho; Smiyan, Svitlana; Kim, HoUng; Lee, Sang Joon; Kim, SuYeon; Park, Won

    2017-02-01

    To assess the efficacy and safety of switching from the infliximab reference product (RP; Remicade) to its biosimilar CT-P13 (Remsima, Inflectra) or continuing CT-P13 in patients with rheumatoid arthritis (RA) for an additional six infusions. This open-label extension study recruited patients with RA who had completed the 54-week, randomised, parallel-group study comparing CT-P13 with RP (PLANETRA; NCT01217086). CT-P13 (3 mg/kg) was administered intravenously every 8 weeks from weeks 62 to 102. All patients received concomitant methotrexate. Endpoints included American College of Rheumatology 20% (ACR20) response, ACR50, ACR70, immunogenicity and safety. Data were analysed for patients who received CT-P13 for 102 weeks (maintenance group) and for those who received RP for 54 weeks and then switched to CT-P13 (switch group). Overall, 302 of 455 patients who completed the PLANETRA study enrolled into the extension. Of these, 158 had received CT-P13 (maintenance group) and 144 RP (switch group). Response rates at week 102 for maintenance versus switch groups, respectively, were 71.7% vs 71.8% for ACR20, 48.0% vs 51.4% for ACR50 and 24.3% vs 26.1% for ACR70. The proportion of patients with antidrug antibodies was comparable between groups (week 102: 40.3% vs 44.8%, respectively). Treatment-emergent adverse events occurred in similar proportions of patients in the two groups during the extension study (53.5% and 53.8%, respectively). Comparable efficacy and tolerability were observed in patients who switched from RP to its biosimilar CT-P13 for an additional year and in those who had long-term CT-P13 treatment for 2 years. NCT01571219; Results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  5. Evaluation of failing hemodialysis fistulas with multidetector CT angiography: Comparison of different 3D planes

    Energy Technology Data Exchange (ETDEWEB)

    Karadeli, E. [Department of Radiology, Baskent University, Faculty of Medicine, Ankara (Turkey); Tarhan, N.C. [Department of Radiology, Baskent University, Faculty of Medicine, Ankara (Turkey)], E-mail: caglat@baskent-ank.edu.tr; Ulu, E.M. Kayahan; Tutar, N.U. [Department of Radiology, Baskent University, Faculty of Medicine, Ankara (Turkey); Basaran, O. [Department of General Surgery, Baskent University, Faculty of Medicine, Ankara (Turkey); Coskun, M.; Niron, E.A. [Department of Radiology, Baskent University, Faculty of Medicine, Ankara (Turkey)

    2009-01-15

    Purpose: To evaluate failing hemodialysis fistula complications using 16-detector MDCTA, and to assess the accuracies of different 3D planes. Materials and methods: Thirty patients (16 men, 14 women, aged 27-79 years) were referred for hemodialysis access dysfunction. Thirty-one MDCTA exams were done prior to fistulography. For MDCTA, contrast was administered (2 mL/kg at 5 mL/s) via a peripheral vein in the contralateral arm. Axial MIP, coronal MIP, and VRT images were constructed. Venous complications were evaluated on axial source images, on each 3D plane, and on all-planes together. Results were analyzed using McNemar test. Results: Axial MIP, VRT and all-planes evaluations were most sensitive for fistula site detection (93%). Coronal MIP had the highest sensitivity, specificity and accuracy (35%, 96%, and 85%, respectively) for detecting venous stenosis. VRT and all-planes had the highest sensitivity and accuracy for detecting aneurysms (100%). All-planes and axial MIP were most sensitive for detecting venous occlusion (61% and 54%). Comparisons of detection frequencies for each venous pathology between the five categories of MDCTA revealed no significant differences (P > 0.05). MDCTA additionally showed 3 partially thrombosed aneurysms, 4 anastomosis site stenosis and 12 arterial complications. Conclusion: MDCTA overall gives low sensitivity for detection of central vein stenosis and moderate sensitivity for occlusion. For most pathology, all-planes evaluation of MDCTA gives highest sensitivity and accuracy rates when compared to other planes. For venous stenosis and occlusion, MDCTA should be considered when ultrasonography and fistulography are inconclusive. MDCTA is helpful in identifying aneurysms, collaterals, partial venous thromboses and additional arterial, anastomosis site pathologies.

  6. Helical computed tomography and the vascularisation of pulmonary sequestration; La Angio-TC en los secuestros pulmonares

    Energy Technology Data Exchange (ETDEWEB)

    Mestre, J.; Marcos, J. [Policlinica Miramar. Palma de Mallorca (Spain)

    2000-07-01

    The authors studied the vascularization in three cases of pulmonary sequestration by means of helical computed tomography (CT) with CT angiography. The technique provided precise images of the anomalous systemic blood flow, suggesting that it is a valid substitute for conventional angiography in the preoperative study of pulmonary sequestrations. (Author)

  7. Preoperative staging of non-small cell lung cancer: prospective comparison of PET/MR and PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Min [Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Seoul National University Medical Research Center, Institute of Radiation Medicine, Seoul (Korea, Republic of); University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of); Goo, Jin Mo; Park, Chang Min [Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Seoul National University Medical Research Center, Institute of Radiation Medicine, Seoul (Korea, Republic of); Seoul National University College of Medicine, Cancer Research Institute, Seoul (Korea, Republic of); Yoon, Soon Ho [Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Seoul National University Medical Research Center, Institute of Radiation Medicine, Seoul (Korea, Republic of); Paeng, Jin Chul; Cheon, Gi Jeong [Seoul National University College of Medicine, Department of Nuclear Medicine, Seoul (Korea, Republic of); Kim, Young Tae [Seoul National University College of Medicine, Cancer Research Institute, Seoul (Korea, Republic of); Seoul National University College of Medicine, Department of Thoracic and Cardiovascular Surgery, Seoul (Korea, Republic of); Park, Young Sik [Seoul National University Hospital, Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul (Korea, Republic of); Seoul National University College of Medicine, Department of Internal Medicine, Seoul (Korea, Republic of)

    2016-11-15

    To prospectively compare the accuracies of PET/MR and PET/CT in the preoperative staging of non-small cell lung cancer (NSCLC). Institutional review board approval and patients' informed consents were obtained. 45 patients with proven or radiologically suspected lung cancer which appeared to be resectable on CT were enrolled. PET/MR was performed for the preoperative staging of NSCLC followed by PET/CT without contrast enhancement on the same day. Dedicated MR images including diffusion weighted images were obtained. Readers assessed PET/MR and PET/CT with contrast-enhanced CT. Accuracies of PET/MR and PET/CT for NSCLC staging were compared. Primary tumour stages (n = 40) were correctly diagnosed in 32 patients (80.0 %) on PET/MR and in 32 patients (80.0 %) on PET/CT (P = 1.0). Node stages (n = 42) were correctly determined in 24 patients (57.1 %) on PET/MR and in 22 patients (52.4 %) on PET/CT (P = 0.683). Metastatic lesions in the brain, bone, liver, and pleura were detected in 6 patients (13.3 %). PET/MR missed one patient with pleural metastasis while PET/CT missed one patient with solitary brain metastasis and two patients with pleural metastases (P = 0.480). This study demonstrated that PET/MR in combination with contrast-enhanced CT was comparable to PET/CT in the preoperative staging of NSCLC while reducing radiation exposure. (orig.)

  8. Single- and dual-energy CT of the abdomen: comparison of radiation dose and image quality of 2nd and 3rd generation dual-source CT

    Energy Technology Data Exchange (ETDEWEB)

    Wichmann, Julian L. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Hardie, Andrew D.; Felmly, Lloyd M.; Perry, Jonathan D.; Varga-Szemes, Akos; De Cecco, Carlo N. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Schoepf, U.J. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Mangold, Stefanie [University Hospital of Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Caruso, Damiano [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' ' Sapienza' ' , Department of Radiological Sciences, Oncological and Pathological Sciences, Latina (Italy); Canstein, Christian [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Siemens Medical Solutions USA, Malvern, PA (United States); Vogl, Thomas J. [University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany)

    2017-02-15

    To compare single-energy (SECT) and dual-energy (DECT) abdominal CT examinations in matched patient cohorts regarding differences in radiation dose and image quality performed with second- and third-generation dual-source CT (DSCT). We retrospectively analysed 200 patients (100 male, 100 female; mean age 61.2 ± 13.5 years, mean body mass index 27.5 ± 3.8 kg/m{sup 2}) equally divided into four groups matched by gender and body mass index, who had undergone portal venous phase abdominal CT with second-generation (group A, 120-kV-SECT; group B, 80/140-kV-DECT) and third-generation DSCT (group C, 100-kV-SECT; group D, 90/150-kV-DECT). The radiation dose was normalised for 40-cm scan length. Dose-independent figure-of-merit (FOM) contrast-to-noise ratios (CNRs) were calculated for various organs and vessels. Subjective overall image quality and reader confidence were assessed. The effective normalised radiation dose was significantly lower (P < 0.001) in groups C (6.2 ± 2.0 mSv) and D (5.3 ± 1.9 mSv, P = 0.103) compared to groups A (8.8 ± 2.3 mSv) and B (9.7 ± 2.4 mSv, P = 0.102). Dose-independent FOM-CNR peaked for liver, kidney, and portal vein measurements (all P ≤ 0.0285) in group D. Subjective image quality and reader confidence were consistently rated as excellent in all groups (all ≥1.53 out of 5). With both DSCT generations, abdominal DECT can be routinely performed without radiation dose penalty compared to SECT, while third-generation DSCT shows improved dose efficiency. (orig.)

  9. Comparison of 64-row and 16-row multidetector CT in the perfusion CT evaluation of acute ischemic stroke patients receiving intravenous thrombolytic therapy

    Energy Technology Data Exchange (ETDEWEB)

    Sillanpaa, Niko; Dastidar, Prasun; Soimakallio, Seppo [Tampere University Hospital, Medical Imaging Centre, PL 2000, Tampere (Finland); Rusanen, Harri [Oulu University Hospital, Department of Neurology, Oulu (Finland); Saarinen, Jukka T. [Tampere University Hospital, Department of Neurology, Tampere (Finland)

    2012-09-15

    Perfusion computed tomography (PCT) is increasingly performed in multimodal CT evaluation of acute ischemic stroke. We compared the technical quality of perfusion studies performed with a 16-row and a 64-row scanner and analyzed the differences between the scanners in their ability to detect perfusion defects. We analyzed retrospectively the clinical and imaging data of 140 consecutive acute (<3 h) stroke patients who underwent multimodal CT evaluation and received intravenous rtPA. Alberta Stroke Program Early CT Score (ASPECTS) was assigned to PCT maps. Clinical and imaging parameters were compared between the two scanners. There were more motion artifacts in the 16-row studies (p = 0.04), and the analysis software was able to completely correct significantly fewer of these (p < 0.001). Both ASPECTS levels were optimally covered in only 29% of the 16-row studies, whereas in the 64-row studies, both levels were invariably optimally visualized (p < 0.001). This significantly decreased the sensitivity of the 16-row scanner to detect perfusion defects in the upper ASPECTS level (p = 0.02). The 64-row scanner was able to detect more perfusion defects that were located entirely outside the ASPECTS regions (p = 0.03). There was no significant difference in the 3-month functional outcome. The 16-row scanner suffered from limited anatomic coverage that decreased the sensitivity to detect perfusion defects in the cranial parts of the middle cerebral artery region. The 16-row studies had poorer technical quality that was in part attributable to higher sampling frequency and smaller slice thickness making the imaging more sensitive to small-scale movement of the patient. (orig.)

  10. Comparison of the Performances of (18)F-FP-CIT Brain PET/MR and Simultaneous PET/CT: a Preliminary Study.

    Science.gov (United States)

    Kwon, SangDon; Chun, KyungAh; Kong, EunJung; Cho, IhnHo

    2016-09-01

    (18)F-FP-CIT [(18)F-fluorinated N-3-fluoropropyl-2-beta-carboxymethoxy-3-beta-(4-iodophenyl) nortropane] has been well established and used for the differential diagnosis of atypical parkinsonian disorders. Recently, combined positron emission tomography (PET)/magnetic resonance (MR) was proposed as a viable alternative to PET/computed tomography (CT). The aim of this study was to compare the performances of conventional (18)F-FP-CIT brain PET/CT and simultaneous PET/MR by visual inspection and quantitative analysis. Fifteen consecutive patients clinically suspected of having Parkinson's disease were recruited for the study.(18)F-FP-CIT PET was performed during PET/CT and PET/MR. PET/CT image acquisition was started 90 min after intravenous injection of (18)F-FP-CIT and then PET/MR images were acquired. Dopamine transporter (DAT) density in bilateral striatal subregions was assessed visually. Quantitative analyses were performed on bilateral striatal volumes of interest (VOIs) using average standardized uptake values (SUVmeans). Intraclass correlation coefficients (ICCs) and their 95 % confidence intervals (CIs) were assessed to compare PET/CT and PET/MR data. Bland-Altman plots were drawn to perform method-comparisons. All subjects showed a preferential decrease in DAT binding in the posterior putamen (PP), with relative sparing of the ventral putamen (VP). Bilateral striatal subregional binding ratio (BR) determined PET/CT and PET/MR demonstrated close interequipment correspondence (BRright caudate - ICC, 0.944; 95 % CI, 0.835-0.981, BRleft caudate - ICC, 0.917; 95 % CI, 0.753-0.972, BRright putamen - ICC, 0.976; 95 % CI, 0.929-0.992 and BRleft putamen - ICC, 0.970; 95 % CI, 0.911-0.990, respectively), and Bland-Altman plots showed interequipment agreement between the two modalities. It is known that MR provides more information about anatomical changes associated with brain diseases and to enable the anatomical allocations of subregions than CT, though

  11. Comparison and Consensus Guidelines for Delineation of Clinical Target Volume for CT- and MR-Based Brachytherapy in Locally Advanced Cervical Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, Akila N., E-mail: aviswanathan@lroc.harvard.edu [Brigham and Women' s Hospital/Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Erickson, Beth [Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Gaffney, David K. [University of Utah Huntsman Cancer Hospital, Salt Lake City, Utah (United States); Beriwal, Sushil [University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania (United States); Bhatia, Sudershan K. [University of Iowa, Iowa City, Iowa (United States); Lee Burnett, Omer [University of Alabama, Birmingham, Alabama (United States); D' Souza, David P.; Patil, Nikhilesh [London Health Sciences Centre and Western University, London, Ontario (Canada); Haddock, Michael G. [Mayo Medical Center, Rochester, Minnesota (United States); Jhingran, Anuja [University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Jones, Ellen L. [University of North Carolina, Chapel Hill, North Carolina (United States); Kunos, Charles A. [Case Western Reserve University, Cleveland, Ohio (United States); Lee, Larissa J. [Brigham and Women' s Hospital/Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Lin, Lilie L. [University of Pennsylvania, Philadelphia, Pennsylvania (United States); Mayr, Nina A. [University of Washington, Seattle, Washington (United States); Petersen, Ivy [Mayo Medical Center, Rochester, Minnesota (United States); Petric, Primoz [Division of Radiotherapy, Institute of Oncology Ljubljana, Ljubljana (Slovenia); Department of Radiation Oncology, National Center for Cancer Care and Research, Doha (Qatar); Portelance, Lorraine [University of Miami Miller School of Medicine, Miami, Florida (United States); Small, William [Loyola University Strich School of Medicine, Chicago, Illinois (United States); Strauss, Jonathan B. [The Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chicago, Illinois (United States); and others

    2014-10-01

    Objective: To create and compare consensus clinical target volume (CTV) contours for computed tomography (CT) and 3-Tesla (3-T) magnetic resonance (MR) image-based cervical-cancer brachytherapy. Methods and Materials: Twenty-three experts in gynecologic radiation oncology contoured the same 3 cervical cancer brachytherapy cases: 1 stage IIB near-complete response (CR) case with a tandem and ovoid, 1 stage IIB partial response (PR) case with tandem and ovoid with needles, and 1 stage IB2 CR case with a tandem and ring applicator. The CT contours were completed before the MRI contours. These were analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with κ statistics as a measure of agreement between participants. The conformity index was calculated for each of the 6 data sets. Dice coefficients were generated to compare the CT and MR contours of the same case. Results: For all 3 cases, the mean tumor volume was smaller on MR than on CT (P<.001). The κ and conformity index estimates were slightly higher for CT, indicating a higher level of agreement on CT. The Dice coefficients were 89% for the stage IB2 case with a CR, 74% for the stage IIB case with a PR, and 57% for the stage IIB case with a CR. Conclusion: In a comparison of MR-contoured with CT-contoured CTV volumes, the higher level of agreement on CT may be due to the more distinct contrast medium visible on the images at the time of brachytherapy. MR at the time of brachytherapy may be of greatest benefit in patients with large tumors with parametrial extension that have a partial or complete response to external beam. On the basis of these results, a 95% consensus volume was generated for CT and for MR. Online contouring atlases are available for instruction at (http://www.nrgoncology.org/Resources/ContouringAtlases/GYNCervicalBrachytherapy.aspx)

  12. Comparison of the performance of {sup 18}F-FP-CIT brain PET/MR and simultaneous PET/CT: A preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Sang Don; Chun, Kyung Ah [Dept. of Nuclear Medicine, Yeungnam University Hospital, Daegu (Korea, Republic of)

    2016-09-15

    {sup 18}F-FP-CIT [{sup 1'}8F-fluorinated N-3-fluoropropyl-2-beta-carboxymethoxy-3-beta-(4-iodophenyl) nortropane] has been well established and used for the differential diagnosis of atypical parkinsonian disorders. Recently, combined positron emission tomography (PET)/magnetic resonance (MR) was proposed as a viable alternative to PET/computed tomography (CT). The aim of this study was to compare the performances of conventional {sup 18}F-FP-CIT brain PET/CT and simultaneous PET/MR by visual inspection and quantitative analysis. Fifteen consecutive patients clinically suspected of having Parkinson's disease were recruited for the study.{sup 18}F-FP-CIT PET was performed during PET/CT and PET/MR. PET/CT image acquisition was started 90 min after intravenous injection of {sup 18}F-FP-CIT and then PET/MR images were acquired. Dopamine transporter (DAT) density in bilateral striatal subregions was assessed visually. Quantitative analyses were performed on bilateral striatal volumes of interest (VOIs) using average standardized uptake values (SUVmeans). Intraclass correlation coefficients (ICCs) and their 95 % confidence intervals (CIs) were assessed to compare PET/CT and PET/MR data. Bland-Altman plots were drawn to perform method-comparisons. All subjects showed a preferential decrease in DAT binding in the posterior putamen (PP), with relative sparing of the ventral putamen (VP). Bilateral striatal subregional binding ratio (BR) determined PET/CT and PET/MR demonstrated close interequipment correspondence (BRright caudate - ICC, 0.944; 95 % CI, 0.835-0.981, BRleft caudate - ICC, 0.917; 95 % CI, 0.753-0.972, BRright putamen - ICC, 0.976; 95 % CI, 0.929-0.992 and BRleft putamen - ICC, 0.970; 95 % CI, 0.911-0.990, respectively), and Bland-Altman plots showed interequipment agreement between the two modalities. It is known that MR provides more information about anatomical changes associated with brain diseases and to enable the anatomical allocations of

  13. Comparison of integrated whole-body [11C]choline PET/MR with PET/CT in patients with prostate cancer.

    Science.gov (United States)

    Souvatzoglou, Michael; Eiber, Matthias; Takei, Toshiki; Fürst, Sebastian; Maurer, Tobias; Gaertner, Florian; Geinitz, Hans; Drzezga, Alexander; Ziegler, Sibylle; Nekolla, Stephan G; Rummeny, Ernst J; Schwaiger, Markus; Beer, Ambros J

    2013-10-01

    To evaluate the performance of conventional [(11)C]choline PET/CT in comparison to that of simultaneous whole-body PET/MR. The study population comprised 32 patients with prostate cancer who underwent a single-injection dual-imaging protocol with PET/CT and subsequent PET/MR. PET/CT scans were performed applying standard clinical protocols (5 min after injection of 793 ± 69 MBq [(11)C]choline, 3 min per bed position, intravenous contrast agent). Subsequently (52 ± 15 min after injection) PET/MR was performed (4 min per bed position). PET images were reconstructed iteratively (OSEM 3D), scatter and attenuation correction of emission data and regional allocation of [(11)C]choline foci were performed using CT data for PET/CT and segmented Dixon MR, T1 and T2 sequences for PET/MR. Image quality of the respective PET scans and PET alignment with the respective morphological imaging modality were compared using a four point scale (0-3). Furthermore, number, location and conspicuity of the detected lesions were evaluated. SUVs for suspicious lesions, lung, liver, spleen, vertebral bone and muscle were compared. Overall 80 lesions were scored visually in 29 of the 32 patients. There was no significant difference between the two PET scans concerning number or conspicuity of the detected lesions (p not significant). PET/MR with T1 and T2 sequences performed better than PET/CT in anatomical allocation of lesions (2.87 ± 0.3 vs. 2.72 ± 0.5; p = 0.005). The quality of PET/CT images (2.97 ± 0.2) was better than that of the respective PET scan of the PET/MR (2.69 ± 0.5; p = 0.007). Overall the maximum and mean lesional SUVs exhibited high correlations between PET/CT and PET/MR (ρ = 0.87 and ρ = 0.86, respectively; both p bone and pelvis. These promising findings suggest that [(11)C]choline PET/MR might have a diagnostic benefit compared to PET/CT in patients with prostate cancer, and now needs to be further evaluated in prospective trials.

  14. Analysis of dose distribution and risk of pneumonitis in stereotactic body radiation therapy for centrally located lung tumors: a comparison of robotic radiosurgery, helical tomotherapy and volumetric modulated arc therapy.

    Science.gov (United States)

    Kannarunimit, Danita; Descovich, Martina; Garcia, Aaron; Chen, Josephine; Weinberg, Vivian; Mcguinness, Christopher; Pinnaduwage, Dilini; Murnane, John; Gottschalk, Alexander R; Yom, Sue S

    2015-02-01

    Stereotactic body radiation therapy (SBRT) to central lung tumors is associated with normal -tissue toxicity. Highly conformal technologies may reduce the risk of complications. This study compares physical dose characteristics and anticipated risks of radiation pneumonitis (RP) among three SBRT modalities: robotic radiosurgery (RR), helical tomotherapy (HT) and volumetric modulated arc therapy (VMAT). Nine patients with central lung tumors ≤5 cm were compared. RR, HT and VMAT plans were developed per RTOG 0831. Dosimetric comparisons included target coverage, conformity index, heterogeneity index, gradient index, maximal dose at 2 cm from target (D2 cm), and dose-volume parameters for organs at risk (OARs). Efficiency endpoints included total beam-on time and monitor units. RP risk was derived from Lyman-Kutcher-Burman modeling on in-house software. The average GTV and PTV were 11.6 ± 7.86 cm(3) and 36.8 ± 18.1 cm(3). All techniques resulted in similar target coverage (p = 0.64) and dose conformity (p = 0.88). While RR had sharper fall-off gradient (p = 0.002) and lower D2 cm (p = 0.02), HT and VMAT produced greater homogeneity (p OAR overlap and small PTV. VMAT and HT produced greater homogeneity, potentially desirable for a large PTV-OAR overlap. VMAT probably yields the lowest RP risk for a large PTV. Understanding subtle differences among these technologies may assist in situations where multiple choices of modality are available. © The Author(s) 2014.

  15. Incremental Value of Subtended Myocardial Mass for Identifying FFR-Verified Ischemia Using Quantitative CT Angiography: Comparison With Quantitative Coronary Angiography and CT-FFR.

    Science.gov (United States)

    Yang, Dong Hyun; Kang, Soo-Jin; Koo, Hyun Jung; Kweon, Jihoon; Kang, Joon-Won; Lim, Tae-Hwan; Jung, Joonho; Kim, Namkug; Lee, June-Goo; Han, Seungbong; Ahn, Jung-Min; Park, Duk-Woo; Lee, Seung-Whan; Lee, Cheol Whan; Park, Seong-Wook; Park, Seung-Jung; Mintz, Gary S; Kim, Young-Hak

    2018-01-12

    This study examined the incremental value of subtended myocardial mass (Vsub) as assessed by coronary computed tomography angiography (CTA) for identifying lesion-specific ischemia verified by invasive fractional flow reserve (FFR) in quantitative coronary CTA. FFR is determined not only by coronary stenosis severity, but also by Vsub. One-step evaluation of combined Vsub and coronary lesion morphology may improve the accuracy of coronary CTA for identifying ischemia-producing lesions. A total of 246 intermediate coronary artery lesions (30% to 80% diameter stenosis) in 220 patients (mean age 61.7 years, 168 men) interrogated by FFR were retrospectively studied. Coronary CTA data were used to assess the Vsub by coronary artery stenosis, minimal lumen area (MLA), percentage of aggregated plaque volume (%APV), positive remodeling, and low-attenuation plaque. The ability of Vsub/MLA2 to discriminate lesions with FFR ≤0.80 was examined. Diagnostic performance, odds ratios, and category-less net reclassification improvements of coronary CTA parameters for FFR-verified (≤0.80) ischemia were evaluated. On-site computed tomography (CT) derived-FFR (CT-FFR) and quantitative coronary angiography (QCA) data were also compared. Of 246 lesions, 84 (34.1%) showed an FFR ≤0.80. Vsub was independently associated with an FFR ≤0.80 (odds ratio: 1.04/1 cm3; p = 0.032) and showed incremental value over MLA. Vsub/MLA2 >4.16 was the best single parameter for discriminating an FFR ≤0.80 with 83.3% sensitivity and 67.9% specificity. The area under the curve (AUC) of Vsub/MLA2 >4.16 (0.80 [95% confidence interval: 0.75 to 0.85]) was better than that of MLA (change in [Δ]AUC: 0.069; p MLA2 >4.16 assessed by coronary CTA shows better diagnostic performance for the detection of ischemia-producing lesions than CT-derived MLA alone or %APV and QCA parameters and was comparable to that of on-site CT-FFR. Copyright © 2018 American College of Cardiology Foundation. Published by

  16. Significance of {sup 18}F-FDG-PET/CT for the identification of adrenal gland and liver metastases in connection with bronchial carcinoma in comparison with conventional diagnostics; Wertigkeit der {sup 18}F-FDG-PET/CT zur Erkennung von Nebennieren- und Leber-Metastasen beim Bronchialkarzinom im Vergleich zur konventionellen Diagnostik

    Energy Technology Data Exchange (ETDEWEB)

    Kley, Adelheid

    2012-02-09

    In the frame of the thesis in the significance of {sup 18}F-FDG-PET/CT for the identification of adrenal gland and liver metastases in connection with bronchial carcinoma in comparison with conventional diagnostics the data of 229 patients were analyzed retrospectively. Compared to PET the diagnostics the use of PET/CT shows higher specificity and sensitivity with respect to the detection of adrenal gland metastases for patients with primary bronchial carcinoma. In case of liver metastases PET/CT is not better than PET, CT or ultrasonography.

  17. Detection of acute small amount of subarachnoid hemorrhage: Comparison between fluid-attenuated inversion recovery MR imaging and CT

    Directory of Open Access Journals (Sweden)

    Maha K. Abdel Ghaffar

    2014-09-01

    Conclusion: FLAIR MRI was more sensitive and more accurate in the diagnosis of acute SAH than CT scan, having a much higher negative predictive value to exclude acute SAH, however its positive predictive value was slightly lower than CT, but there was no statistically significant difference statistically between the two in diagnosis of SAH.

  18. Thymic involvement in immune recovery during antiretroviral treatment of HIV infection in adults; comparison of CT and sonographic findings

    DEFF Research Database (Denmark)

    Kolte, Lilian; Strandberg, Charlotte; Dreves, Anne-Mette

    2002-01-01

    In adult HIV-infected patients, thymic size evaluated from CT scans seems to be important to the degree of immune reconstitution obtainable during treatment with highly active antiretroviral therapy (HAART). To examine whether ultrasound is as reliable as CT for estimating thymic size and predict...... the importance of a large thymus to immune recovery during HAART....

  19. Staging accuracy of pancreatic cancer: Comparison between non-contrast-enhanced and contrast-enhanced PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Yoneyama, Tomohiro [Department of Radiology, Yokohama City University, Graduate School of Medicine, Yokohama (Japan); Tateishi, Ukihide, E-mail: utateish@yokohama-cu.ac.jp [Department of Radiology, Yokohama City University, Graduate School of Medicine, Yokohama (Japan); Endo, Itaru [Department of Surgery, Yokohama City University, Graduate School of Medicine, Yokohama (Japan); Inoue, Tomio [Department of Radiology, Yokohama City University, Graduate School of Medicine, Yokohama (Japan)

    2014-10-15

    Purpose: Our aim was to clarify the diagnostic impact of contrast-enhanced (CE) {sup 18}F-fluorodeoxyglucose (FDG)–positron emission tomography (PET)/computed tomography (CT) for staging of pancreatic cancer compared to non-CE PET/CT. Method and materials: Between April 2006 and November 2009, a total of 95 patients (age range, 36–83 years [mean age, 67]) with primary pancreatic cancer underwent {sup 18}F-FDG PET/CT examinations. Diagnostic accuracy was compared between non-CE PET/CT and CE PET/CT. Images were analyzed visually and quantitatively by two blinded reviewers. Reference standard was histological examination in 48 patients (51%) and/or confirmation of an obvious progression in number and/or size of the lesions on follow-up CT examinations in 47 patients (49%). Results: For T-staging, invasion of duodenum (n = 20, 21%), mesentery (n = 12, 13%), and retroperitoneum (n = 13, 14%) was correctly diagnosed by both modalities. The ROC analyses revealed that the Az values of celiac artery (CA), common hepatic artery (CHA), splenic artery (SV), and superior mesenteric vein (SMV) invasion were significantly higher in the CE PET/CT group for both readers. Nodal metastasis was correctly diagnosed by CE PET/CT in 38 patients (88%) and by non-CE PET/CT in 45 patients (87%). Diagnostic accuracies of nodal metastasis in two modalities were similar. Using CE PET/CT, distant metastasis, scalene node metastasis, and peritoneal dissemination were correctly assigned in 39 patients (91%), while interpretation based on non-CE PET/CT revealed distant metastasis, scalene node metastasis, and peritoneal dissemination in 42 patients (81%). Diagnostic accuracy of distant metastasis, scalene node metastasis, and peritoneal dissemination with CE PET/CT was significantly higher than that of non-CE PET/CT (p < 0.05). Conclusion: CE PET/CT allows a more precise assessment of distant metastasis, scalene node metastasis, and peritoneal dissemination in patients with pancreatic cancer.

  20. Diagnostic performance of {sup 18}F-fluorothymidine PET/CT for primary colorectal cancer and its lymph node metastasis: comparison with {sup 18}F-fluorodeoxyglucose PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Nakajo, Masatoyo [Kagoshima University, Graduate School of Medical and Dental Sciences, Department of Radiology, Kagoshima (Japan); Nanpuh Hospital, Department of Radiology, Kagoshima (Japan); Nakajo, Masayuki; Jinguji, Megumi; Fukukura, Yoshihiko [Kagoshima University, Graduate School of Medical and Dental Sciences, Department of Radiology, Kagoshima (Japan); Kajiya, Yoriko; Tani, Atushi [Nanpuh Hospital, Department of Radiology, Kagoshima (Japan); Nishimata, Nobuaki; Shimaoka, Shunji; Nihara, Tohru [Nanpuh Hospital, Department of Gastroenterology, Kagoshima (Japan); Aridome, Kuniaki [Nanpuh Hospital, Department of Surgery, Kagoshima (Japan); Tanaka, Sadao [Nanpuh Hospital, Department of Pathology, Kagoshima (Japan); Koriyama, Chihaya [Kagoshima University, Graduate School of Medical and Dental Sciences, Department of Epidemiology and Preventive Medicine, Kagoshima (Japan)

    2013-08-15

    To examine the diagnostic performance of {sup 18}F-fluorothymidine (FLT) PET/CT in primary and metastatic lymph node colorectal cancer foci in comparison with {sup 18}F-fluorodeoxyglucose (FDG) PET/CT. The study population comprised 28 patients with 30 newly diagnosed colorectal cancers who underwent surgical resection of the primary lesion and regional lymph nodes after both FLT and FDG PET/CT. The associations between SUVmax levels and pathological factors were evaluated using the Mann-Whitney U or Kruskal-Wallis test. Differences in diagnostic indexes for detecting nodal metastasis between the two tracers were estimated using the McNemar exact or {chi} {sup 2} test. All 30 primary cancers (43.0 {+-} 20.0 mm, range 14 - 85 mm) were visualized by both tracers, but none of the FLT SUVmax values exceeded the FDG SUVmax values in any of the primary cancers (6.6 {+-} 2.4 vs. 13.6 {+-} 5.8, p < 0.001). The sensitivity, specificity and accuracy for detecting nodal metastasis were 41 % (15/37), 98.8 % (493/499) and 94.8 % (508/536) for FDG PET/CT, and 32 % (12/37), 98.8 % (493/499) and 94.2 % (505/536) for FLT PET/CT, respectively. The sensitivity (p = 0.45), specificity (p = 0.68) and accuracy (p = 0.58) were not different between the tracers. Nodal uptake of FLT and FDG was discordant in 7 (19 %) of 37 metastatic nodes. There were ten concordant true-positive nodes of which six showed higher FDG SUVmax and four showed higher FLT SUVmax, but the difference between FDG and FLT SUVmax was not significant (5.56 {+-} 3.55 and 3.62 {+-} 1.45, respectively; p = 0.22). FLT has the same potential as FDG in PET/CT for the diagnosis of primary and nodal foci of colorectal cancer despite significantly lower FLT uptake in primary foci. (orig.)

  1. Flexible helical-axis stellarator

    Science.gov (United States)

    Harris, Jeffrey H.; Hender, Timothy C.; Carreras, Benjamin A.; Cantrell, Jack L.; Morris, Robert N.

    1988-01-01

    An 1=1 helical winding which spirals about a conventional planar, circular central conductor of a helical-axis stellarator adds a significant degree of flexibility by making it possible to control the rotational transform profile and shear of the magnetic fields confining the plasma in a helical-axis stellarator. The toroidal central conductor links a plurality of toroidal field coils which are separately disposed to follow a helical path around the central conductor in phase with the helical path of the 1=1 winding. This coil configuration produces bean-shaped magnetic flux surfaces which rotate around the central circular conductor in the same manner as the toroidal field generating coils. The additional 1=1 winding provides flexible control of the magnetic field generated by the central conductor to prevent the formation of low-order resonances in the rotational transform profile which can produce break-up of the equilibrium magnetic surfaces. Further, this additional winding can deepen the magnetic well which together with the flexible control provides increased stability.

  2. Double Helical Gear Performance Results in High Speed Gear Trains

    Science.gov (United States)

    Handschuh, Robert F.; Ehinger, Ryan; Sinusas, Eric; Kilmain, Charles

    2010-01-01

    The operation of high speed gearing systems in the transmissions of tiltrotor aircraft has an effect on overall propulsion system efficiency. Recent work has focused on many aspects of high-speed helical gear trains as would be used in tiltrotor aircraft such as operational characteristics, comparison of analytical predictions to experimental data and the affect of superfinishing on transmission performance. Baseline tests of an aerospace quality system have been conducted in the NASA Glenn High-Speed Helical Gear Train Test Facility and have been described in earlier studies. These earlier tests had utilized single helical gears. The results that will be described in this study are those attained using double helical gears. This type of gear mesh can be configured in this facility to either pump the air-oil environment from the center gap between the meshing gears to the outside of tooth ends or in the reverse direction. Tests were conducted with both inward and outward air-oil pumping directions. Results are compared to the earlier baseline results of single helical gears.

  3. A retrospective comparison between 68Ga-DOTA-TOC PET/CT and 18F-DOPA PET/CT in patients with extra-adrenal paraganglioma.

    Science.gov (United States)

    Kroiss, Alexander; Putzer, Daniel; Frech, Andreas; Decristoforo, Clemens; Uprimny, Christian; Gasser, Rudolf Wolfgang; Shulkin, Barry Lynn; Url, Christoph; Widmann, Gerlig; Prommegger, Rupert; Sprinzl, Georg Mathias; Fraedrich, Gustav; Virgolini, Irene Johanna

    2013-12-01

    (18)F-Fluoro-L-dihydroxyphenylalanine ((18)F-DOPA) PET offers high sensitivity and specificity in the imaging of nonmetastatic extra-adrenal paragangliomas (PGL) but lower sensitivity in metastatic or multifocal disease. These tumours are of neuroendocrine origin and can be detected by (68)Ga-DOTA-Tyr(3)-octreotide ((68)Ga-DOTA-TOC) PET. Therefore, we compared (68)Ga-DOTA-TOC and (18)F-DOPA as radiolabels for PET/CT imaging for the diagnosis and staging of extra-adrenal PGL. Combined cross-sectional imaging was the reference standard. A total of 5 men and 15 women (age range 22 to 73 years) with anatomical and/or histologically proven extra-adrenal PGL were included in this study. Of these patients, 5 had metastatic or multifocal lesions and 15 had single sites of disease. Comparative evaluation included morphological imaging with CT and functional imaging with (68)Ga-DOTA-TOC PET and (18)F-DOPA PET. The imaging results were analysed on a per-patient and a per-lesion basis. The maximum standardized uptake value (SUVmax) of each functional imaging modality in concordant tumour lesions was measured. Compared with anatomical imaging, (68)Ga-DOTA-TOC PET and (18)F-DOPA PET each had a per-patient and per-lesion detection rate of 100% in nonmetastatic extra-adrenal PGL. However, in metastatic or multifocal disease, the per-lesion detection rate of (68)Ga-DOTA-TOC was 100% and that of (18)F-DOP