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Sample records for spiral ct reconstruction

  1. Pulmonary sequestration: diagnosis with three dimensional reconstruction using spiral CT

    International Nuclear Information System (INIS)

    Nie Yongkang; Zhao Shaohong; Cai Zulong; Yang Li; Zhao Hong; Zhang Ailian; Huang Hui

    2003-01-01

    Objective: To evaluate the role of three dimensional (3D) reconstruction using spiral CT in the diagnosis of pulmonary sequestration. Methods: Ten patients with pulmonary sequestration were analyzed. The diagnoses were confirmed by angiography in 2 patients, by operation in 2 patients, and by CT angiography in 6 patients. All patients were examined with Philips SR 7000 or GE Lightspeed Plus scanner. CT images were transferred to a workstation and 3D reconstruction was performed. All images were reviewed and analyzed by two radiologists. Results: Among 10 patients, the pulmonary sequestration was in the right lower lobe in 1 patient and in the left lower lobe in 9 patients. Anomalous systemic arteries originated from thoracic aorta in 8 patients and from celiac artery in 2 patients. On plain CT scan, there were 4 patients with patchy opacities, 3 patients with hilar mass accompanying vascular engorgement and profusion in adjacent parenchyma, 2 patients with finger-like appendage surrounded by hyper-inflated lung, and 1 patient with lung mass-like lesion. Enhanced CT revealed anomalous systemic arteries in 9 patients and drainage vein in 7 patients. Maximum intensity projection (MIP) and curvilinear reconstruction could depict the abnormal systemic artery and drainage vein in sequestration. Surface shadow display (SSD) and volume rendering (VR) could delineate the anomalous systemic artery. Conclusion: 3D reconstruction with enhanced spiral CT can depict anomalous systemic artery and drainage vein and it is the first method of choice in diagnosing pulmonary sequestration

  2. Motion estimation and compensation in dynamic spiral CT reconstruction

    International Nuclear Information System (INIS)

    Kimdon, J.; Grangeat, P.; Koenig, A.; Bonnet, St.

    2004-01-01

    Respiratory and cardiac motion causes blurring in dynamic X-ray Computed Tomography (CT). Fast scans reduce this problem, but they require a higher radiation dose per time period to maintain the signal to noise ratio of the resulting images, thereby magnifying the health risk to the patient. As an alternative to increased radiation, our team has already developed a cone-beam reconstruction algorithm based on a dynamic particle model that estimates, predicts, and compensates for respiratory motion in circular X-ray CT. The current paper presents an extension of this method to spiral CT, applicable to modern multi-slice scanners that take advantage of the speed and dose benefits of helical trajectories. We adapted all three main areas of the algorithm: backprojection, prediction, and compensation/accumulation. In backprojection, we changed the longitudinal re-binning technique, filter direction, and the method of enforcing the data sufficiency requirements. For prediction, we had to be careful of objects appearing and disappearing as the scanner bed advanced. For compensation/accumulation, we controlled the reconstruction time and combined images to cover a greater longitudinal extent for each phase in the respiratory or cardiac cycle. Tests with moving numerical phantoms demonstrate that the algorithm successfully improves the temporal resolution of the images without increasing the dose or reducing the signal-to-noise ratio. (authors)

  3. The value of spiral CT thin imaging reconstruction in the diagnosis of obstructive jaundice

    International Nuclear Information System (INIS)

    Huang Zhi; Liu Zhang; Yang Chaoxiang; Lin Chengye; Zhang Li; Li Yuxiang; Ma Yunyan; Xiao Haisong; Lu Zhifeng; Wang Bo; Zhou Yunhong

    2009-01-01

    Objective: To approach the value of spiral CT thin imaging reconstruction in the diagnosis of obstructive jaundice in order to improve the correctness of the diagnosis. Methods: Analysis the cases' clinical manifestation and the CT images, who were diagnosed as obstructive jaundice by operation. All of cases had high-resolution computed tomograyhy scan. The thickness and the interval is 5mm, reconstructed the thickness and the interval to 1 mm and 1.5 mm, then send the images to the workstation and MRR were processed. Analysis the date with the pathology. Results: Spiral CT thin imaging reconstruction have 98% and 93% in the accuracy of location and characterization in the obstruction. Conclusion: The spiral CT thin imaging reconstruction is a good method to improve the accuracy of location and characterization in the obstructive jaundice. (authors)

  4. Value of multi-slice spiral CT MPVR reconstruction in the diagnosis of acute appendicitis

    International Nuclear Information System (INIS)

    Wang Kang; Zhao Zehua; Wang Zhi; Wang Weizhong; Xu Songsen; Zhang Miao; Liu Wenjin; Zhang Guozhen; Feng Dianxu

    2005-01-01

    Objective: To investigate the value of multi-slice spiral CT MPVR reconstruction in the diagnosis of acute appendicitis. Methods: A total of 39 patients with clinically suspected acute appendicitis underwent surgery from February, 2002 to September, 2003. They were prospectively examined before surgery with routine CT scanning and MPVR reconstruction spiral CT. 31 cases of appendicitis were confirmed after appendectomy. CT scans and surgery-pathology reports were evaluated on a five-grade scale from hyperemic-edematous appendix to abscess (normal appendix: 0 grade). Results: The results of spiral CT MPVR reconstruction were compared with the surgical and pathologic findings at appendectomy, yielding an accuracy of 87.2%, sensitivity of 90.3%, specificity of 75%, positive predictive value of 93.3%, and negative predictive value of 66.7%, respectively. Results of routine CT yielded an accuracy of 38.5%, sensitivity of 38.7%, specificity of 37.5%, positive predictive value of 70.6%, and negative predictive value of 13.6%, respectively. MPVR reconstruction signs of 28 patients with acute appendicitis included enlarged appendix ( > 6 mm) (96.4%), appendicoliths (26.7%), caecal apical thickening (36.7%), periappendiceal inflammation (71.4%), and abscess (10.7%). Conclusion: The use of spiral CT MPVR reconstruction in patients with equivocal clinical presentation suspected of having acute appendicitis can lead to a significant improvement in the preoperative diagnosis and maybe a decrease in surgical-pathologic severity of appendiceal disease. (authors)

  5. Technique and value of three dimensional reconstruction of stones in the renal pelvis using spiral CT

    International Nuclear Information System (INIS)

    Fink, B.K.; Fink, U.; Pentenrieder, M.; Kohz, P.; Englmeier, H.K.; Schmeller, N.

    1994-01-01

    5 patients with staghorn calculi in the renal pelvis were examined by spiral CT. From the raw data three dimensional reconstructions of the stones were obtained. In all patients it was possible to compare the three dimensional model with the stone following performance of percutaneous lithopaxy and endoscopic removal of the fragments. In all cases the three dimensional reconstruction provided a realistic image of the stones and was of practical value for the urologist for preoperative diagnosis and intraoperative control. (orig.) [de

  6. Clinical application of the three-dimensional reconstruction of spiral CT pneumocolon

    International Nuclear Information System (INIS)

    Yu Shenping; Li Ziping; Xu Dasheng; Lin Erjian; Lin Peizhang; Xu Qiaolan

    2000-01-01

    Objective: To evaluate the clinical role of the 3 types of reconstruction of the spiral CT pneumocolon in the diagnosis of colon lesions. Methods: Three types of reconstruction with spiral CT pneumocolon including air cast imaging (ACI), CT virtual endoscopy (CTVE), and multiple planner reconstruction (MPR) in 34 patients with colorectal cancer or polyps were correlated with surgical pathology respectively. Results: Among the 34 patients, 30 was colorectal cancer and 6 was polyps (2 of which in the proximal lumen of 2 colon cancer). (1) Comparison between the 3 types of the spiral CT pneumocolon reconstruction and pathology in colorectal cancer. 1) ACI: tumor patterns: coincide (n =22), anti-coincide (n = 8); tumor extension: coincide (n = 24), anti-coincide (n = 6); tumor size: coincide (n = 28), anti-coincide (n = 2). 2) CTVE: tumor patterns: coincide (n = 26), anti-coincide (n = 4); tumor extension: coincide (n = 25), anti-coincide ( n 5); tumor size: coincide (n = 23), anti-coincide (n = 7). 3) MPR: tumor patterns: coincide (n = 24), anti-coincide (n = 6); tumor extension: coincide (n = 30), anti-coincide (n = 0); tumor size: coincide (n = 26), anti-coincide (n = 4). (2) Comparison between the 3 types of the spiral CT pneumocolon reconstruction and pathology in colorectal polyps: the lesions were displayed in 4 (ACI) and in 6 (CTVE and MPR). Conclusion: (1) For the diagnosis of colorectal cancers: CTVE was the best means to display the tumor patterns, MPR most correct to judge the tumor extension, and ACI most suitable to measure the tumor size. (2) For the diagnosis of colorectal polyps, ACI can be used for oriented diagnosis, CTVE can well display the intra-luminal three-dimensional structure and can be used for characteristic diagnosis, MPR can be used for differential diagnosis

  7. Spiral CT of the pancreas. The value of small field-of-view targeted reconstruction

    International Nuclear Information System (INIS)

    Nishiharu, T.; Yamashita, Y.; Ogata, I.; Sumi, S.; Mitsuzaki, K.; Takahashi, M.

    1998-01-01

    Purpose: To compare the value of a retrospective targeted high-resolution spiral CT to the standard reconstruction technique in the assessment of pancreatic diseases. Material and methods: Spiral CT pancreatic images of a standard-size reconstruction protocol were compared prospectively with those of a retrospective targeted high-spatial-resolution reconstruction protocol in 30 patients. Prior to clinical evaluation, a phantom study was performed to evaluate the spatial resolution and signal-to-noise ratio of both protocols. Results: The high-resolution protocol achieved a good signal-to-noise ratio with acceptable spatial resolution. Phantom studies revealed increased image noise (+17%) with an increase in spatial resolution (+100%). In patients studied with the high-resolution protocol, the increase in noise was not significant but there was a marked improvement in the definition of small details. Conclusion: Images obtained with a targeted high-spatial-resolution reconstruction protocol showed superior lesion definition and vascular opacification compared with those obtained with a standard-size reconstruction protocol. This technique may have potential in the evaluation of small pancreatic abnormalities. (orig.)

  8. Peripheral pulmonary arteries: identification at multi-slice spiral CT with 3D reconstruction

    International Nuclear Information System (INIS)

    Coche, Emmanuel; Pawlak, Sebastien; Dechambre, Stephane; Maldague, Baudouin

    2003-01-01

    Our objective was to analyze the peripheral pulmonary arteries using thin-collimation multi-slice spiral CT. Twenty consecutive patients underwent enhanced-spiral multi-slice CT using 1-mm collimation. Two observers analyzed the pulmonary arteries by consensus on a workstation. Each artery was identified on axial and 3D shaded-surface display reconstruction images. Each subsegmental artery was measured at a mediastinal window setting and compared with anatomical classifications. The location and branching of every subsegmental artery was recorded. The number of well-visualized sub-subsegmental arteries at a mediastinal window setting was compared with those visualized at a lung window setting. Of 800 subsegmental arteries, 769 (96%) were correctly visualized and 123 accessory subsegmental arteries were identified using the mediastinal window setting. One thousand ninety-two of 2019 sub-subsegmental arteries (54%) identified using the lung window setting were correctly visualized using the mediastinal window setting. Enhanced multi-slice spiral CT with thin collimation can be used to analyze precisely the subsegmental pulmonary arteries and may identify even more distal pulmonary arteries. (orig.)

  9. Clinical application of 16-slice spiral CT in reconstruction imaging of coronary artery for diagnosing coronary disense

    International Nuclear Information System (INIS)

    Mao Xinbo; Zhu Xinjin; Zeng Huiliang; Chen Xueguang

    2005-01-01

    Objective: An evaluation of the reconstructed imaging of coronary arteries with 16-slice spiral CT in diagnosis of coronary disease. Methods: The reconstructed images of coronary arteries obtained on a 16-slice spiral CT scanner were reviewed in 60 cases, on which the following techniques were applied: retrospective ECG-gating, Segment method with 75% R-R interval, volume rendering technique (VRT), maximum intensity projection (MIP), mulfiplanar reconstruction (MPR), curved planar reconstruction (CPR) and CT virtual endoscopy (CTVE). Results: In all 60 cases, different stages of CHD were revealed in 21 cases; none abnormality was found in 33; and images were in poor quality in 2 cases, which was available for diagnosis. There were 4 stents planted in 4 cases: soft plaque suspected in lcase, patent in 2 and occlude in 1. Conclusion: The reconstructed imaging of coronary arteries with 16-slice spiral CT is superior modality in evaluation of severe coronary stenosis, plaques, and the pantency of the intra-luminal stents, which is an efficient and non-invasive imaging in diagnosis of early-stage CHD and screening in high risk population. (authors)

  10. Motion estimation and compensation in dynamic spiral CT reconstruction; Estimation et compensation de mouvement en reconstruction dynamique de tomodensitometrie helicoidale

    Energy Technology Data Exchange (ETDEWEB)

    Kimdon, J.; Grangeat, P.; Koenig, A.; Bonnet, St

    2004-07-01

    Respiratory and cardiac motion causes blurring in dynamic X-ray Computed Tomography (CT). Fast scans reduce this problem, but they require a higher radiation dose per time period to maintain the signal to noise ratio of the resulting images, thereby magnifying the health risk to the patient. As an alternative to increased radiation, our team has already developed a cone-beam reconstruction algorithm based on a dynamic particle model that estimates, predicts, and compensates for respiratory motion in circular X-ray CT. The current paper presents an extension of this method to spiral CT, applicable to modern multi-slice scanners that take advantage of the speed and dose benefits of helical trajectories. We adapted all three main areas of the algorithm: backprojection, prediction, and compensation/accumulation. In backprojection, we changed the longitudinal re-binning technique, filter direction, and the method of enforcing the data sufficiency requirements. For prediction, we had to be careful of objects appearing and disappearing as the scanner bed advanced. For compensation/accumulation, we controlled the reconstruction time and combined images to cover a greater longitudinal extent for each phase in the respiratory or cardiac cycle. Tests with moving numerical phantoms demonstrate that the algorithm successfully improves the temporal resolution of the images without increasing the dose or reducing the signal-to-noise ratio. (authors)

  11. Diagnosis of multidetector spiral CT and its reconstruction techniques in trachea and principal bronchus tumors

    Energy Technology Data Exchange (ETDEWEB)

    Mingyue, Luo; Hong, Shan; Zaibo, Jiang; Lufang, Li; Jiansheng, Zhang [Zhongshan Univ., Guangzhou (China). The Third Univ. Hospital, Dept. of Radiology; Lijia, Gu; Shaohong, Huang; Yi, Jin; Zhiqiang, Hou

    2003-12-01

    Objective: To investigate the clinical diagnostic value of multidetector spiral CT (MSCT) and its reconstruction techniques including multiplanar volume reformation (MPVR), volume rendering (VR), and virtual bronchoscopy (VB) in the trachea and principal bronchus tumors. Methods: Thin slice MSCT scanning was performed in 31 patients with suspected trachea or principal bronchus tumors, and image reconstruction data were formed after retro-reconstructing of initial scanning data. MPVR, VR, and VB images were obtained respectively by postprocessing of image reconstruction data with MPVR, VR, and VB image processing software in AW workstation. The findings of MSCT initial axial images, MPVR, VR, and VB images were compared with surgical and pathological results. Results: MSCT initial axial images combined with MPVR, VR, and VB images displayed the locations (tracheae, n=19; right principal bronchi, n=6; left principal bronchi, n=6), morphologies (endoluminal nodular tumors with narrow bases, n=2; endoluminal nodular tumors with wide bases, n=13; intraluminal and extraluminal massive tumors, n=16), internal features (1 had homogeneous density, 1 had low density, they both without obvious enhancement; 23 squamous cell carcinomas and 3 adenocarcinomas had fairly homogeneous density and rather obvious enhancement; 1 had homogeneous density, 1 had inhomogeneous density, 1 had punctate calcification, all with obvious enhancement), extramural invasion situations (broke through only serous membrane, n=1; no clear border with right atelectatic lung tissue, n=1; ranges of extramural invasion 4-56 mm, n=14), morphologies of luminal stenoses (eccentric, n=1; irregular, n=26; circular, n=3; conical interruption, n=1), extents (mild, n=5; moderate, n=7; severe, n=19); measured longitudinal invasion ranges (only 3 mm, n=1; invaded the whole right principal bronchus wall and carina, n=1; 5-68 mm, n=29), and distances between principal bronchus tumors and carina (invaded carina, n=1

  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

    International Nuclear Information System (INIS)

    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

    •Superiority of spiral versus sequential cCT in image quality and organ-specific-radiation dose.•Spiral cCT: lower organ-specific-radiation-dose in eye lense compared to tilted sequential cCT.•State-of-the-art IR spiral cCT techniques has significant advantages over sequential cCT techniques. Superiority of spiral versus sequential cCT in image quality and organ-specific-radiation dose. Spiral cCT: lower organ-specific-radiation-dose in eye lense compared to tilted sequential cCT. State-of-the-art IR spiral cCT techniques has significant advantages over sequential cCT techniques. 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

  13. A new approximate algorithm for image reconstruction in cone-beam spiral CT at small cone-angles

    International Nuclear Information System (INIS)

    Schaller, S.; Flohr, T.; Steffen, P.

    1996-01-01

    This paper presents a new approximate algorithm for image reconstruction with cone-beam spiral CT data at relatively small cone-angles. Based on the algorithm of Wang et al., our method combines a special complementary interpolation with filtered backprojection. The presented algorithm has three main advantages over Wang's algorithm: (1) It overcomes the pitch limitation of Wang's algorithm. (2) It significantly improves z-resolution when suitable sampling schemes are applied. (3) It avoids the waste of applied radiation dose inherent to Wang's algorithm. Usage of the total applied dose is an important requirement in medical imaging. Our method has been implemented on a standard workstation. Reconstructions of computer-simulated data of different phantoms, assuming sampling conditions and image quality requirements typical to medical CT, show encouraging results

  14. Multi-slice spiral CT coronary angiography: influence of heart rate and reconstruction window on image quality

    International Nuclear Information System (INIS)

    Mao Dingbiao; Hua Yanqing; Wang Mingpeng; Zhang Guozhen; Wu Weilan; Hu Fei; Ge Xiaojun; Ding Qiyong

    2004-01-01

    Objective: To evaluate the influence of heart rate and reconstruction window on image quality of multi-slice spiral CT coronary angiography. Methods: Retrospectively ECG-gated MSCT coronary angiography were performed in 80 healthy cases. Results: Four coronary (RCA, LM, LAD, LCX) segments were analyzed in each patient with regard to image quality. 82.1% (46/56) of the coronary segments were sufficient for analysis in patients with heart rate ≤60 bpm, 63.4% (104/164) with 61-70 bpm, 41.2%(28/68) with 71-80 bpm, and 31.2%(10/32) with>80 bpm, respectively. The left anterior descending artery, left circumflex artery, and the right coronary artery were best visualized when the reconstruction window was 60%-70%, 50%-60%, and 50%-70%, respectively. Conclusion: Image quality of MSCT coronary angiography is highly dependent on heart rate and reconstruction window

  15. The postprocessing techniques in renal artery reconstructions and clinical application with multidetector spiral CT angiography

    International Nuclear Information System (INIS)

    Yu Yuanxin; Liang Changhong; Zhang Zhonglin; Xie Shufei; Liu Yubao; Tang Xiangzhou

    2005-01-01

    Objective: To investigate the value and predominance for imaging postprocessing techniques of renal artery variation and lesions by multidetector spiral CT angiography. Methods: 51 patients with renal artery disease including 12 artery variation, 27 artery stenosis, 3 renal anenrysm, 3 thrombosis of renal artery and 3 dissecting aneurysm of renal artery by SSD, MIP and CPR were enrolled. The effectiveness of these imaging postprocessing methods was compared, 29 of them were confirmed by DSA and 3 by operation, others were checked by MRA and follow up. Results: All abnormalities and diseases were cleariy displayed. The specificity and sensitivity were 100% respectively. In the all imaging postprocessing techniques, MPR can clearly display the calcification of the arteries, stenosis, embolism, aneurysm but do not display the anatomy satisfactorily. MIP can not only clearly display the anatomy but display the different configurations. VR can display the artery figures but can not display the information of lumen of blood vessels. SSD can display the complex vessel anatomy but it was influenced by its threshold selection. CPR can spread and display directly the tortuous renal artery and measure the section area of stenosis. Conclusions: MSCTA is helpful to accurately display the renal artery variation and lesions. Both MIP and VR are the best choice to illustrate the renal artery abnormalities. And MPR and SSD are assistant in the diagnosis of' renal artery lesions. (authors)

  16. Image Quality of 3rd Generation Spiral Cranial Dual-Source CT in Combination with an Advanced Model Iterative Reconstruction Technique: A Prospective Intra-Individual Comparison Study to Standard Sequential Cranial CT Using Identical Radiation Dose.

    Science.gov (United States)

    Wenz, Holger; Maros, Máté E; Meyer, Mathias; Förster, Alex; Haubenreisser, Holger; Kurth, Stefan; Schoenberg, Stefan O; Flohr, Thomas; Leidecker, Christianne; Groden, Christoph; Scharf, Johann; Henzler, Thomas

    2015-01-01

    To prospectively intra-individually compare image quality of a 3rd generation Dual-Source-CT (DSCT) spiral cranial CT (cCT) to a sequential 4-slice Multi-Slice-CT (MSCT) while maintaining identical intra-individual radiation dose levels. 35 patients, who had a non-contrast enhanced sequential cCT examination on a 4-slice MDCT within the past 12 months, underwent a spiral cCT scan on a 3rd generation DSCT. CTDIvol identical to initial 4-slice MDCT was applied. Data was reconstructed using filtered backward projection (FBP) and 3rd-generation iterative reconstruction (IR) algorithm at 5 different IR strength levels. Two neuroradiologists independently evaluated subjective image quality using a 4-point Likert-scale and objective image quality was assessed in white matter and nucleus caudatus with signal-to-noise ratios (SNR) being subsequently calculated. Subjective image quality of all spiral cCT datasets was rated significantly higher compared to the 4-slice MDCT sequential acquisitions (pspiral compared to sequential cCT datasets with mean SNR improvement of 61.65% (p*Bonferroni0.05spiral cCT with an advanced model IR technique significantly improves subjective and objective image quality compared to a standard sequential cCT acquisition acquired at identical dose levels.

  17. Diagnosing extracranial atherosclerotic diseases with spiral CT

    International Nuclear Information System (INIS)

    Moran, C.J.; Vannier, M.W.; Erickson, K.K.; Broderick, D.F.; Kido, D.K.; Yoffie, R.L.

    1991-01-01

    This paper reports that this discovery study was performed to determine whether extracranial carotid artery plaques could be diagnosed with a new CT technique (spiral CT) that allows nondistorted three-dimensional (3D) reconstructions in the z axis. Twenty carotid arteries were examined with spiral CT in normal volunteers and in patients suspected of having atherosclerotic plaques in the extracranial carotid arteries. The Somatom Plus CT table was advanced at a constant rate, the x-ray tube was continuously rotated, and 3D data were continuously acquired. Sixty milliliters of nonionic contrast medium was injected intravenously previous to and during the acquisition of data. The carotid bifurcations were identified in all patients. Planar images, similar to conventional intraarterial angiograms, were routinely produced from the volumetric CT data

  18. Imaging of head and neck tumors -- methods: CT, spiral-CT, multislice-spiral-CT

    International Nuclear Information System (INIS)

    Baum, Ulrich; Greess, Holger; Lell, Michael; Noemayr, Anton; Lenz, Martin

    2000-01-01

    Spiral-CT is standard for imaging neck tumors. In correspondence with other groups we routinely use spiral-CT with thin slices (3 mm), a pitch of 1.3-1.5 and an overlapping reconstruction increment (2-3 mm). In patients with dental fillings a short additional spiral parallel to the corpus of the mandible reduces artifacts behind the dental arches and improves the diagnostic value of CT. For the assessment of the base of the skull, the orbital floor, the palate and paranasal sinuses an additional examination in the coronal plane is helpful. Secondary coronal reconstructions of axial scans are helpful in the evaluation of the crossing of the midline by small tumors of the tongue base or palate. For an optimal vascular or tissue contrast a sufficient volume of contrast medium and a start delay greater than 70-80 s are necessary. In our opinion the best results can be achieved with a volume of 150 ml, a flow of 2.5 ml/s and a start delay of 80 s. Dynamic enhanced CT is only necessary in some special cases. There is clear indication for dynamic enhanced CT where a glomus tumor is suspected. Additional functional CT imaging during i-phonation and/or Valsalva's maneuver are of great importance to prove vocal cords mobility. Therefore, imaging during i-phonation is an elemental part of every thorough examination of the hypopharynx and larynx region. Multislice-spiral-CT allows almost isotropic imaging of the head and neck region and improves the assessment of tumor spread and lymph node metastases in arbitrary oblique planes. Thin structures (the base of the skull, the orbital floor, the hard palate) as well as the floor of the mouth can be evaluated sufficiently with multiplanar reformations. Usually, additional coronal scanning is not necessary with multislice-spiral-CT. Multislice-spiral-CT is especially advantageous in defining the critical relationships of tumor and lymph node metastases and for functional imaging of the hypopharynx and larynx not only in the

  19. Colour-coded three-dimensional reconstruction from spiral CT data sets: Improvement from the physical point of view

    International Nuclear Information System (INIS)

    Wunderlich, A.P.; Lenz, M.; Kirsten, R.; Gerhardt, P.

    1993-01-01

    This paper demonstrates the possibility of improving the spatial depth impression of colour-coded three-dimensional reconstructions by modulation of colour saturation. Patients were observed with spiral computed tomography (slice thickness 10 mm, table feed 10 mm/s, reconstruction of overlapping axial images at 2 mm increment). Interesting anatomical and pathological objects (vessels, organs, tumours, metastases) were segmented, colour-coded, and reconstructed three-dimensionally. Spatial depth impression of the coloured objects could be improved by modulating not only the brightness, but also the colour saturation. (orig.) [de

  20. Diagnosis of pancreatic tumors by spiral angio CT

    International Nuclear Information System (INIS)

    Miura, Kohi; Nakao, Norio; Takayasu, Yukio; Okawa, Tomohisa

    1995-01-01

    Spiral angio were performed with injection of 30 ml of contrast material at a rate of 1 ml/sec with a scan delay of 6 sec through catheter into the celiac artery while the blood flow of the superior mesenteric artery (SMA) was occluded by the inflated balloon catheter. Spiral CT scans were obtained using Somatom Plus (Siemens). Parameter for spiral CT were 24-sec acquisition time, 5 mm collimation, 5 mm/sec table incrementation. Reconstructions were performed every 5 mm. Pancreatic cancers were characteristically depicted with spiral angio CT as hypodensity relative to normal enhanced pancreatic parenchyma. On dynamic angio CT studies performed in pancreatic cancers, the area of cancer and normal parenchyma had maximum level of enhancement at 10-15 sec after injection of contrast material via catheter into the celiac, and there was no difference in enhancement between tumor and normal parenchyma. On the other hand, the lesions of cancer were revealed as hypodensity with spiral angio CT. In case of chronic pancreatitis, the enhancement of the entire pancreas obtained with spiral angio CT was homogeneous. Insulinoma in the tail of pancreas was detected by spiral angio CT but was not detected by both selective angiography and conventional CT. Three-dimensional (3-D) rendering spiral angio CT data shows the extent of vascular involvement by pancreatic cancer and provides useful information for surgical planning. Spiral angio CT is the most useful procedure for diagnosis of pancreatic tumor. (author)

  1. Multislice helical CT (MSCT) for mid-facial trauma: optimization of parameters for scanning and reconstruction; Mehrschicht-Spiral-CT (MSCT) beim Mittelgesichtstrauma: Optimierung der Aufnahme- und Rekonstruktionsparameter

    Energy Technology Data Exchange (ETDEWEB)

    Dammert, S.; Funke, M.; Obernauer, S.; Grabbe, E. [Abt. Roentgendiagnostik I, Georg-August-Univ. Goettingen (Germany); Merten, H.A. [Abt. fuer Mund-, Kiefer- und Gesichtschirurgie, Georg-August-Univ. Goettingen (Germany)

    2002-07-01

    Purpose: To determine the optimal scan parameters in multislice helical CT (MSCT) of the facial bone complex for both axial scanning and multiplanar reconstructions. Material and Methods: An anthropomorphic skull phantom was examined with a MSCT. Axial scans were performed with continuously increasing collimations (4 x 1.25 - 4 x 2.5 mm), tube current (20 - 200 mA) and table speeds (3.75 mm/rot. and 7.5 mm/rot.). Multiplanar reconstructions in coronal and parasagittal planes with different reconstruction increment and slice thickness were evaluated in terms of image noise, contour artifacts and visualisation of anatomical structures. Results: The best image quality was obtained with a collimation of 4 x 1.25 mm and a - table speed of 3.75 mm/rot. A reconstruction increment of 0.6 mm achieved the best time to image quality relation. With these parameters the bone structures were depicted in an optimal way without artifacts. The tube current could be reduced to 50 mA without significant loss of image quality. The optimized protocol was used for regular routine examinations in patients with facial trauma (n = 66). Conclusions: Low-dose MSCT using thin collimation, low table speed and small reconstruction increments provides excellent data for both axial images and multiplanar reconstructions in patients with facial trauma. An additional examination in coronal orientation is therefore no longer necessary. (orig.) [German] Zielsetzung: Verbesserung der Aufnahme- und Rekonstruktionsparameter in der Mehrschicht Spiral-CT (MSCT) zur Untersuchung des knoechernen Mittelgesichtes in verschiedenen Ebenen. Material und Methode: Ein anthropomorphes Schaedel-Phantom wurde in axialer Schichtfuehrung mit einem MSCT untersucht, wobei die Kollimation (1,25 - 2,5 mm), der Tischvorschubfaktor (Pitch 3 - 6) und der Roehrenstrom (20 - 200 mA) systematisch variiert wurden. Aus den Volumendatensaetzen wurden jeweils koronare und parasagittale Sekundaerreformationen mit unterschiedlichen

  2. Accuracy of spiral CT and 3D reconstruction in the detection of acute pulmonary embolism - development of an animal model using porcine lungs and technical specimens. Development of an animal model using porcine lungs and technical specimens

    International Nuclear Information System (INIS)

    Ries, B.G.; Kauczor, H.U.; Thelen, M.; Konerding, M.A.

    2001-01-01

    Purpose: To develop a model for simulation the CT morphologic situation of acute pulmonary embolism, to evaluate the accuracy of spiral CT and 3D reconstruction in the detection of artificial emboli and to investigate the influence of the orientation of emboli depending on z-axis orientation. Materials and Methods: Standardized artificial emboli made of wax and of defined size and shape were positioned into the pulmonary arteries of porcine lungs. Castings of the embolized pulmonary arterial trees were made by injection of a special opaque resin. After performance of spiral CT the data sets of the emboli and the pulmonary arteries were post-processed. The 3D segmentations were compared with the anatomic preparation to evaluate the accuracy of spiral CT/3D reconstruction-technique. Technical specimens simulating CT-morphology of acute embolized vessels underwent spiral CT in six different positions with respect to the z-axis. The CT data were reconstructed using a standardized and a contrastadapted method with interactive correction. The 3D emboli were analysed under qualitative aspects, and measurements of their extent were done. Results: In nearly 91%, there was complete agreement between CT and the corresponding findings at the anatomical preparation. Measurements of the 3D reconstructed technical specimens showed discrepancies of shape and size in dependence of the size of the original preparation, orientation and reconstruction technique. Overestimation up to 4 mm and underestimation to 2,2 mm were observed. Measurements of preparations with heights from 14 to 26 mm showed variances of ±1,5 mm (∝6-11%). Conclusion: The presented models are suitable to simulate CT morphology of acute pulmonary embolism under ex-vivo conditions. Accuracy in the detection of artificial emboli using spiral CT/3D reconstruction is affected by localization, size and orientation of the emboli and the reconstruction technique. (orig.) [de

  3. Spiral scan long object reconstruction through PI line reconstruction

    International Nuclear Information System (INIS)

    Tam, K C; Hu, J; Sourbelle, K

    2004-01-01

    The response of a point object in a cone beam (CB) spiral scan is analysed. Based on the result, a reconstruction algorithm for long object imaging in spiral scan cone beam CT is developed. A region-of-interest (ROI) of the long object is scanned with a detector smaller than the ROI, and a portion of it can be reconstructed without contamination from overlaying materials. The top and bottom surfaces of the ROI are defined by two sets of PI lines near the two ends of the spiral path. With this novel definition of the top and bottom ROI surfaces and through the use of projective geometry, it is straightforward to partition the cone beam image into regions corresponding to projections of the ROI, the overlaying objects or both. This also simplifies computation at source positions near the spiral ends, and makes it possible to reduce radiation exposure near the spiral ends substantially through simple hardware collimation. Simulation results to validate the algorithm are presented

  4. Accuracy of spiral CT and 3D reconstruction in the detection of acute pulmonary embolism - development of an animal model using porcine lungs and technical specimens. Development of an animal model using porcine lungs and technical specimens; Diagnostik der akuten Lungenembolie mittels Spiral-CT und 3D-Rekonstruktion. Entwicklung eines Tiermodells und technischer Probekoerper im Ex-vivo-Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Ries, B.G. [Klinik und Poliklinik fuer Radiologie, Univ. Mainz (Germany); Klinik fuer Radiologische Diagnostik, RWTH Aachen (Germany); Kauczor, H.U.; Thelen, M. [Klinik und Poliklinik fuer Radiologie, Univ. Mainz (Germany); Konerding, M.A. [Anatomisches Inst., Mainz Univ (Germany)

    2001-02-01

    Purpose: To develop a model for simulation the CT morphologic situation of acute pulmonary embolism, to evaluate the accuracy of spiral CT and 3D reconstruction in the detection of artificial emboli and to investigate the influence of the orientation of emboli depending on z-axis orientation. Materials and Methods: Standardized artificial emboli made of wax and of defined size and shape were positioned into the pulmonary arteries of porcine lungs. Castings of the embolized pulmonary arterial trees were made by injection of a special opaque resin. After performance of spiral CT the data sets of the emboli and the pulmonary arteries were post-processed. The 3D segmentations were compared with the anatomic preparation to evaluate the accuracy of spiral CT/3D reconstruction-technique. Technical specimens simulating CT-morphology of acute embolized vessels underwent spiral CT in six different positions with respect to the z-axis. The CT data were reconstructed using a standardized and a contrastadapted method with interactive correction. The 3D emboli were analysed under qualitative aspects, and measurements of their extent were done. Results: In nearly 91%, there was complete agreement between CT and the corresponding findings at the anatomical preparation. Measurements of the 3D reconstructed technical specimens showed discrepancies of shape and size in dependence of the size of the original preparation, orientation and reconstruction technique. Overestimation up to 4 mm and underestimation to 2,2 mm were observed. Measurements of preparations with heights from 14 to 26 mm showed variances of {+-}1,5 mm ({proportional_to}6-11%). Conclusion: The presented models are suitable to simulate CT morphology of acute pulmonary embolism under ex-vivo conditions. Accuracy in the detection of artificial emboli using spiral CT/3D reconstruction is affected by localization, size and orientation of the emboli and the reconstruction technique. (orig.) [German] Ziel: Die Entwicklung

  5. The effect of pitch in multislice spiral/helical CT

    International Nuclear Information System (INIS)

    Wang, G.; Vannier, M.W.

    2000-01-01

    The purpose of this study is to understand the effect of pitch on raw data interpolation in multislice spiral/helical computed tomography (CT) and provide guidelines for scanner design and protocol optimization. Multislice spiral CT is mainly characterized by the three parameters: the number of detector arrays, the detector collimation, and the table increment per x-ray source rotation. The pitch in multislice spiral CT is defined as the ratio of the table increment over the detector collimation in this study. In parallel to the current framework for studying longitudinal image resolution, the central fan-beam rays of direct and opposite directions are considered, assuming a narrow cone-beam angle. Generally speaking, sampling in the Radon domain by the direct and opposite central rays is nonuniform along the longitudinal axis. Using a recently developed methodology for quantifying the sensibility of signal reconstruction from non-uniformly sampled finite points, the effect of pitch on raw data interpolation is analyzed in multislice spiral CT. Unlike single-slice spiral CT, in which image quality decreases monotonically as the pitch increases, the sensibility of raw data interpolation in multislice spiral CT increases, suggesting that image quality does not decrease monotonically in this case. The most favorable pitch can be found from the sensitivity-slice spiral CT is provided. The study on the effect of pitch using the sensitivity analysis approach reveals the fundamental characteristics of raw data interpolation in multislice spiral CT, and gives insights into interaction between pitch and image quality. These results may be valuable for design of multislice spiral CT scanners and imaging protocol optimization in clinical applications. (authors)

  6. Spiral CT versus conventional CT in the preoperative assessment of metallic intraocular foreign bodies

    International Nuclear Information System (INIS)

    Prokesch, R.; Bankier, A.; Ba-Ssalamah, A.; Imhof, H.; Lakits, A.; Scholda, C.

    1998-01-01

    Purpose: To compare the effectiveness of spiral CT versus conventional CT in the preoperative assessment of metallic intraocular foreign bodies. Results: All foreign bodies were detected by each scanning modality on the axial and on the reconstructed planes. The quality of the axial images was similar for spiral and conventional CT. The spiral technique provided high-quality reconstructed images which allowed accurate localization of the foreign bodies in all cases. Reconstructions by conventional technique were inadequate for preoperative assessment. The examination time for the total orbital volume was 18 s for spiral CT and 52 s for conventional CT. Radiation dose delivered to the lens was 35 mGy for spiral CT and 56 mGy for conventional CT axial scanning. Conclusion: Spiral CT multiplanar offers several significant advantages for the preoperative assessment of metallic intraocular foreign bodies compared to the conventional CT technique in clinical practice, including short examination time, minimized motion artifacts, reduced radiation exposure, and accurate localization. (orig.) [de

  7. Dual-source spiral CT with pitch up to 3.2 and 75 ms temporal resolution: Image reconstruction and assessment of image quality

    International Nuclear Information System (INIS)

    Flohr, Thomas G.; Leng Shuai; Yu Lifeng; Allmendinger, Thomas; Bruder, Herbert; Petersilka, Martin; Eusemann, Christian D.; Stierstorfer, Karl; Schmidt, Bernhard; McCollough, Cynthia H.

    2009-01-01

    Purpose: To present the theory for image reconstruction of a high-pitch, high-temporal-resolution spiral scan mode for dual-source CT (DSCT) and evaluate its image quality and dose. Methods: With the use of two x-ray sources and two data acquisition systems, spiral CT exams having a nominal temporal resolution per image of up to one-quarter of the gantry rotation time can be acquired using pitch values up to 3.2. The scan field of view (SFOV) for this mode, however, is limited to the SFOV of the second detector as a maximum, depending on the pitch. Spatial and low contrast resolution, image uniformity and noise, CT number accuracy and linearity, and radiation dose were assessed using the ACR CT accreditation phantom, a 30 cm diameter cylindrical water phantom or a 32 cm diameter cylindrical PMMA CTDI phantom. Slice sensitivity profiles (SSPs) were measured for different nominal slice thicknesses, and an anthropomorphic phantom was used to assess image artifacts. Results were compared between single-source scans at pitch=1.0 and dual-source scans at pitch=3.2. In addition, image quality and temporal resolution of an ECG-triggered version of the DSCT high-pitch spiral scan mode were evaluated with a moving coronary artery phantom, and radiation dose was assessed in comparison with other existing cardiac scan techniques. Results: No significant differences in quantitative measures of image quality were found between single-source scans at pitch=1.0 and dual-source scans at pitch=3.2 for spatial and low contrast resolution, CT number accuracy and linearity, SSPs, image uniformity, and noise. The pitch value (1.6≤pitch≤3.2) had only a minor impact on radiation dose and image noise when the effective tube current time product (mA s/pitch) was kept constant. However, while not severe, artifacts were found to be more prevalent for the dual-source pitch=3.2 scan mode when structures varied markedly along the z axis, particularly for head scans. Images of the moving

  8. Dual-source spiral CT with pitch up to 3.2 and 75 ms temporal resolution: image reconstruction and assessment of image quality.

    Science.gov (United States)

    Flohr, Thomas G; Leng, Shuai; Yu, Lifeng; Aiimendinger, Thomas; Bruder, Herbert; Petersilka, Martin; Eusemann, Christian D; Stierstorfer, Karl; Schmidt, Bernhard; McCollough, Cynthia H

    2009-12-01

    To present the theory for image reconstruction of a high-pitch, high-temporal-resolution spiral scan mode for dual-source CT (DSCT) and evaluate its image quality and dose. With the use of two x-ray sources and two data acquisition systems, spiral CT exams having a nominal temporal resolution per image of up to one-quarter of the gantry rotation time can be acquired using pitch values up to 3.2. The scan field of view (SFOV) for this mode, however, is limited to the SFOV of the second detector as a maximum, depending on the pitch. Spatial and low contrast resolution, image uniformity and noise, CT number accuracy and linearity, and radiation dose were assessed using the ACR CT accreditation phantom, a 30 cm diameter cylindrical water phantom or a 32 cm diameter cylindrical PMMA CTDI phantom. Slice sensitivity profiles (SSPs) were measured for different nominal slice thicknesses, and an anthropomorphic phantom was used to assess image artifacts. Results were compared between single-source scans at pitch = 1.0 and dual-source scans at pitch = 3.2. In addition, image quality and temporal resolution of an ECG-triggered version of the DSCT high-pitch spiral scan mode were evaluated with a moving coronary artery phantom, and radiation dose was assessed in comparison with other existing cardiac scan techniques. No significant differences in quantitative measures of image quality were found between single-source scans at pitch = 1.0 and dual-source scans at pitch = 3.2 for spatial and low contrast resolution, CT number accuracy and linearity, SSPs, image uniformity, and noise. The pitch value (1.6 pitch 3.2) had only a minor impact on radiation dose and image noise when the effective tube current time product (mA s/pitch) was kept constant. However, while not severe, artifacts were found to be more prevalent for the dual-source pitch = 3.2 scan mode when structures varied markedly along the z axis, particularly for head scans. Images of the moving coronary artery phantom

  9. Dual-source spiral CT with pitch up to 3.2 and 75 ms temporal resolution: Image reconstruction and assessment of image quality

    Energy Technology Data Exchange (ETDEWEB)

    Flohr, Thomas G.; Leng Shuai; Yu Lifeng; Allmendinger, Thomas; Bruder, Herbert; Petersilka, Martin; Eusemann, Christian D.; Stierstorfer, Karl; Schmidt, Bernhard; McCollough, Cynthia H. [Siemens Healthcare, Computed Tomography, 91301 Forchheim, Germany and Department of Diagnostic Radiology, Eberhard-Karls-Universitaet, 72076 Tuebingen (Germany); Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905 (United States); Siemens Healthcare, Computed Tomography, 91301 Forchheim (Germany); Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905 (United States)

    2009-12-15

    Purpose: To present the theory for image reconstruction of a high-pitch, high-temporal-resolution spiral scan mode for dual-source CT (DSCT) and evaluate its image quality and dose. Methods: With the use of two x-ray sources and two data acquisition systems, spiral CT exams having a nominal temporal resolution per image of up to one-quarter of the gantry rotation time can be acquired using pitch values up to 3.2. The scan field of view (SFOV) for this mode, however, is limited to the SFOV of the second detector as a maximum, depending on the pitch. Spatial and low contrast resolution, image uniformity and noise, CT number accuracy and linearity, and radiation dose were assessed using the ACR CT accreditation phantom, a 30 cm diameter cylindrical water phantom or a 32 cm diameter cylindrical PMMA CTDI phantom. Slice sensitivity profiles (SSPs) were measured for different nominal slice thicknesses, and an anthropomorphic phantom was used to assess image artifacts. Results were compared between single-source scans at pitch=1.0 and dual-source scans at pitch=3.2. In addition, image quality and temporal resolution of an ECG-triggered version of the DSCT high-pitch spiral scan mode were evaluated with a moving coronary artery phantom, and radiation dose was assessed in comparison with other existing cardiac scan techniques. Results: No significant differences in quantitative measures of image quality were found between single-source scans at pitch=1.0 and dual-source scans at pitch=3.2 for spatial and low contrast resolution, CT number accuracy and linearity, SSPs, image uniformity, and noise. The pitch value (1.6{<=}pitch{<=}3.2) had only a minor impact on radiation dose and image noise when the effective tube current time product (mA s/pitch) was kept constant. However, while not severe, artifacts were found to be more prevalent for the dual-source pitch=3.2 scan mode when structures varied markedly along the z axis, particularly for head scans. Images of the moving

  10. Multi-slice spiral CT multiplanar reconstruction findings of localized fat collection adjection to the subdiaphragmatic inferior vena cava

    International Nuclear Information System (INIS)

    Cao Hetao; Lu Jian; Zhao Jinli; Liu Tingting; Qin Jufeng; Xu Wen; Qin Jiangchun; Jiang Junkang

    2012-01-01

    Objective: To discusses the MSCT multiplanar reconstruction manifestation (MPR) of localized fat collection adjection to subdiaphragmatic inferior vena cava (IVC fat ). Methods: The thoracic and abdominal MSCT scan data of 8246 patients were browsed,45 patients with presumed IVC fat on axial CT scans were further studied prospectively with MSCT MPR. The predisposing position of IVC fat and its relationship with IVC were observed. It was divided into two kinds of intraluminal type and extraluminal type according to the angle of IVC fat with respect of the wall of IVC.The other 50 patients without IVC fat were randomly selected as the control group. The sagittal inclination angle (SIA) and diameter ratio (DR) between supra- and sub-diaphragmatic IVC between the two groups were compared by using t test. Results: The detection rate was 0.55% (45/8246). Of which hepatic vein lacuna 8 patients, subdiaphragmatic gap medial to IVC 28 patients and IVC groove 9 patients. The shape of IVC fat showed mainly for the round, oval and crescents on axial CT scans, of 15 patients intraluminal type, 4 showed 'target signs'. The shape of IVC fat showed mainly for 'half-moon' at MPR.The SIA and DR at IVC fat group were 21.62° ± 8.42° and 2.01 ±0.84 respectively, at control group were 16.75° ±7.82° (t=1.594, P>0.05) and 1.31 ±0.28 (t=2.341, P<0.05) respectively. Conclusion: The round, oval or half of limited fat density shadow adjection to subdiaphragmatic inferior vena cava which similar to in the lumen is the characteristic performance of IVC fat , it may be an anatomical variation. (authors)

  11. Measurement of lung volumes : usefulness of spiral CT

    International Nuclear Information System (INIS)

    Kang, Ho Yeong; Kwak, Byung Kook; Lee, Sang Yoon; Kim, Soo Ran; Lee, Shin Hyung; Lee, Chang Joon; Park, In Won

    1996-01-01

    To evaluate the usefulness of spiral CT in the measurement of lung volumes. Fifteen healthy volunteers were studied by both spirometer and spiral CT at full inspiration and expiration in order to correlated their results, including total lung capacity (TLC), vital capacity (VC) and residual volume (RV). 3-D images were reconstructed from spiral CT, and we measured lung volumes at a corresponding CT window range ; their volumes were compared with the pulmonary function test (paired t-test). The window range corresponding to TLC was from -1000HU to -150HU (p=0.279, r=0.986), and for VC from -910HU to -800HU (p=0.366, r=0.954) in full-inspiratory CT. The optimal window range for RV in full-expiratory CT was from -1000HU to -450HU (p=0.757, r=0.777), and TLC-VC in full-inspiratory CT was also calculated (p=0.843, r=0.847). Spiral CT at full inspiration can used to lung volumes such as TLC, VC and RV

  12. Initial clinical experience with spiral CT angiography in the abdomen

    International Nuclear Information System (INIS)

    Gaa, J.; Stehling, M.K.; Costello, P.

    1993-01-01

    The latest developments in modern CT instruments, offering scanning times of a second, opened up new possibilities in CT imaging in combination with the spiral technique. The data set normally taken with single-breath-hold technique is free of respiratory artefacts and thus is a good basis for accurate 3D image reconstruction. Spiral CTA allows a non-invasive 3D imaging of various blood vessels. Patients with abdominal aortic aneurysms of aorto-iliac bypass can be examined as outpatients within 15 minutes. (orig.) [de

  13. Improved reconstruction for IDEAL spiral CSI

    DEFF Research Database (Denmark)

    Hansen, Rie Beck; Mariager, Christian; Laustsen, Christoffer

    2017-01-01

    In this study we demonstrate how reconstruction for IDEAL spiral CSI (spectroscopic imaging scheme developed for hyperpolarized dynamic metabolic MR imaging) can be improved by using regularization with a sparsity constraint. By exploiting sparsity of the spectral domain, IDEAL spiral CSI can...

  14. Spiral CT-angiography of the aorta

    NARCIS (Netherlands)

    Balm, R.; Eikelboom, B. C.; van Leeuwen, M. S.; Noordzij, J.

    1994-01-01

    AIMS: To determine whether the new technique of CT-angiography was accurate in displaying the complex anatomy of the aorta and its major branches. METHODS: Seventeen patients with a variety of aortic pathology were examined. Using a spiral CT-scanner a volumetric scan was made during injection of

  15. Spiral CT for evaluation of chest trauma

    International Nuclear Information System (INIS)

    Roehnert, W.; Weise, R.

    1997-01-01

    After implementation of spiral CT in our department, we carried out an analysis for determining anew the value of CT as a modality of chest trauma diagnosis in the emergency department. The retrospective study covers a period of 10 months and all emergency patients with chest trauma exmined by spiral CT. The major lesions of varying seriousness covered by this study are: pneumothorax, hematothorax, pulmonary contusion or laceration, mediastinal hematoma, rupture of a vessel, injury of the heart and pericardium. The various fractures are not included in this study. In many cases, spiral CT within relatively short time yields significant diagnostic findings, frequently saving additional angiography. A rigid diagnostic procedure cannot be formulated. Plain-film chest radiography still remains a diagnostic modality of high value. (Orig.) [de

  16. Principles of spiral CT: III. Quality assurance

    International Nuclear Information System (INIS)

    Suess, C.; Kalender, W.A.

    1998-01-01

    Since its introduction in 1989 spiral CT has gained wide clinical acceptance and meanwhile it covers a large range of CT applications. This new technology, however, has not yet been recognized and acknowledged in the national or international regulations on scanner quality assurance (QA) programs. The conventional QA procedures should be extended to check the distribution of resolution and noise within the image plane. Imaging performance in the axial direction constitutes one of the major advantages of spiral scanning. Therefore, the slice sensitivity profiles and the spatial and low-contrast resolution along the z-axis have to be assessed. The high demands on table feed accuracy require additional tests. We suggest phantoms and procedures to check and quantify these parameters. Thereby, we hope to support the ongoing discussion about spiral CT quality assurance. (orig.) [de

  17. Spiral CT manifestations of spherical pneumonia

    International Nuclear Information System (INIS)

    Li Xiaohong; Yang Hongwei; Xu Chunmin; Qin Xiu

    2008-01-01

    Objective: To explore the Spiral CT manifestations and differential diagnosis of spherical pneumonia. Methods: 18 cases of spherical pneumonia and 20 cases of peripheral pulmonary carcinoma were selected, both of them were confirmed by clinic and/or pathology. The SCT findings of both groups were compared retrospectively. Results: Main spiral CT findings of spherical pneumonia were showed as followings: square or triangular lesions adjacent to pleura; with irregular shape, blurry, slightly lobulated margin, sometimes with halo sign. Small inflammatory patches and intensified vascular markings around the lesions were seen. Lesions became smaller or vanished after short-term anti-inflammatory treatment. Conclusion: Spherical pneumonia showed some characteristics on Spiral CT scan, which are helpful in diagnosis and differential diagnosis of this disease. (authors)

  18. The role of spiral CT in pelvic trauma management

    International Nuclear Information System (INIS)

    Cheung, E.C.F.; Fung, K.K.L.

    1999-01-01

    Rapid and accurate assessment of pelvic injury is critical for good patient management. Plain X-ray is often used as a preliminary evaluation of the injury but this may not give adequate diagnosis of the acetabulum fracture, subtle fracture of the pelvic bone and the associated soft tissue injuries. Nowadays, spiral CT has taken an increasing role in the evaluation of pelvic trauma. It gives a rapid assessment of the bone and soft tissue injuries as compared to conventional CT. Besides, 2-D (multiplanar imaging) and 3-D image reconstruction with multiple angle views, provide the maximum information which facilitates detailed pelvic trauma evaluation. Three cases were used to illustrate the role of spiral CT in pelvic trauma management. Copyright (1999) Blackwell Science Pty Ltd

  19. Spiral CT for evaluation of chest trauma; Spiral-CT beim Thoraxtrauma

    Energy Technology Data Exchange (ETDEWEB)

    Roehnert, W. [Universitaetsklinikum Dresden (Germany). Inst. und Poliklinik fuer Radiologische Diagnostik; Weise, R. [Universitaetsklinikum Dresden (Germany). Inst. und Poliklinik fuer Radiologische Diagnostik

    1997-07-01

    After implementation of spiral CT in our department, we carried out an analysis for determining anew the value of CT as a modality of chest trauma diagnosis in the emergency department. The retrospective study covers a period of 10 months and all emergency patients with chest trauma exmined by spiral CT. The major lesions of varying seriousness covered by this study are: pneumothorax, hematothorax, pulmonary contusion or laceration, mediastinal hematoma, rupture of a vessel, injury of the heart and pericardium. The various fractures are not included in this study. In many cases, spiral CT within relatively short time yields significant diagnostic findings, frequently saving additional angiography. A rigid diagnostic procedure cannot be formulated. Plain-film chest radiography still remains a diagnostic modality of high value. (Orig.) [Deutsch] Nach Einfuehrung der Spiral-CT in unserer Einrichtung versuchten wir, den Stellenwert der Computertomographie in der Notfalldiagnostik des Thoraxtraumas neu zu bestimmen. Dazu wurden retrospektiv ueber einen Zeitraum von 10 Monaten alle mittels Spiral-CT untersuchten Notfallpatienten mit Thoraxverletzungen ausgewertet. Im Vordergrund standen folgende Befunde unterschiedlichen Schweregrades: Pneumothorax, Haematothorax, Lungenkontusion/-lazeration, Mediastinalhaematom, Gefaessruptur, Herz- und Herzbeutelverletzung. Auf die unterschiedlichen Frakturen wird bewusst nicht naeher eingegangen. In vielen Faellen liefert die Spiral-CT mit relativ geringem Zeitaufwand wesentliche diagnostische Aussagen. Haeufig kann auf eine Angiographie verzichtet werden. Ein starres diagnostisches Stufenschema laesst sich nicht definieren. Die Thoraxuebersichtsaufnahme besitzt einen unveraendert hohen Stellenwert. (orig.)

  20. Kidney spiral CT, indications, realization, results

    International Nuclear Information System (INIS)

    Braunschweig, R.; Beilicke, M.; Hundt, W.; Breiteneder, T.; Reiser, M.

    1999-01-01

    The introduction of spiral computed tomography (spiral CT) has vastly enriched the methodologically diversity of computer-tomographic scans. It allows for the recording of different perfusion or excretion stages of the kidney parenchyma of the urine draining paths by carrying out long-distance, phase-identical multiple examinations of the retroperitoneum. The description of the findings which are characterized by their local and contrasts behavior is possible. The following report describes the indications and technological process of kidney spiral CT using kidney-typical intravenous contrast media. Special emphasis is put on the advantages and limits of multiple phase spiral CT. Decisive preconditions are: 1. Specific clinical query, 2. selection of the corresponding phase contrasts of the kidneys and uretra or bladder, 3. exact technical and temporal adjustment of the acquisition parameters. Scanning times are in the range of seconds. The overall examination can be carried out quick and without any major strain on the part of the patient. A sound proof and a general differentiation of focal kideny lesions can be derived from the acquired data. This is also true for kidneys and ureters findings. Bladder findings can be localized and differentiated according to stage. More than two 'spiral acquisitions' should be carried out with restraint taking exposure to radiation into account. Due to the sound registration of focal lesions, its capability of reproduction and its short-time examination, the spiral CT of the kidneys can be said to be the most effective current scanning method of the retroperitoneum following clinical examinations and sonography. (orig.) [de

  1. 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

    Directory of Open Access Journals (Sweden)

    Holger Wenz

    2016-01-01

    Conclusions: 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.

  2. Spiral CT and radiation dose

    International Nuclear Information System (INIS)

    Imhof, H.; Schibany, N.; Ba-Ssalamah, A.; Czerny, C.; Hojreh, A.; Kainberger, F.; Krestan, C.; Kudler, H.; Noebauer, I.; Nowotny, R.

    2003-01-01

    Recent studies in the USA and Europe state that computed tomography (CT) scans compromise only 3-5% of all radiological exams, but they contribute 35-45% of total radiation dose to the patient population. These studies lead to concern by several public authorities. Basis of CT-dose measurements is the computed tomography dose index (CTDI), which was established 1981. Nowadays there are several modifications of the CTDI values, which may lead to confusion. It is suggested to use the standardized CTDI-100 w. value together with the dose length product in all CT-examinations. These values should be printed on all CT-images and allows an evaluation of the individualized patient dose. Nowadays, radiologist's aim must be to work at the lowest maximal diagnostic acceptable signal to noise ratio. To decrease radiation dose radiologist should use low kV and mA, but high pitches. Newly developed CT-dose-reduction soft-wares and filters should be installed in all CT-machines. We should critically compare the average dose used for a specific examination with the reference dose used in this country and/or Europe. Greater differences should caution the radiologist. Finally, we as radiologists must check very carefully all indications and recommend alternative imaging methods. But we have also to teach our customers--patients and medical doctors who are non-radiologists--that a 'good' image is not that which show all possible information, but that which visualize 'only' the diagnostic necessary information

  3. Three-dimensional spiral CT for neurosurgical planning.

    Science.gov (United States)

    Klein, H M; Bertalanffy, H; Mayfrank, L; Thron, A; Günther, R W; Gilsbach, J M

    1994-08-01

    We carried out 22 examinations to determine the value of three-dimensional (3D) volumetric CT (spiral CT) for planning neurosurgical procedures. All examinations were carried out on a of the first generation spiral CT. A tube model was used to investigate the influence of different parameter settings. Bolus injection of nonionic contrast medium was used when vessels or strongly enhancing tumours were to be delineated. 3D reconstructions were carried out using the integrated 3D software of the scanner. We found a table feed of 3 mm/s with a slice thickness of 2 mm and an increment of 1 mm to be suitable for most purposes. For larger regions of interest a table feed of 5 mm was the maximum which could be used without blurring of the 3D images. Particular advantages of 3D reconstructed spiral scanning were seen in the planning of approaches to the lower clivus, acquired or congenital bony abnormalities and when the relationship between vessels, tumour and bone was important.

  4. Three-dimensional spiral CT for neurosurgical planning

    International Nuclear Information System (INIS)

    Klein, H.M.; Bertalanffy, H.; Mayfrank, L.; Thron, A.; Guenther, R.W.; Gilsbach, J.M.

    1994-01-01

    We carried out 22 examinations to determine the value of three-dimensional (3D) volumetric CT (spiral CT) for planning neurosurgical procedures. All examinations were carried out on a of the first generation spiral CT. A tube model was used to investigate the influence of different parameter settings. Bolus injection of nonionic contrast medium was used when vessels or strongly enhancing tumours were to be delineated. 3D reconstructions were carried out using the integrated 3D software of the scanner. We found a table feed of 3 mm/s with a slice thickness of 2 mm and an increment of 1 mm to be suitable for most purposes. For larger regions of interest a table feed of 5 mm was the maximum which could be used without blurring of the 3D images. Particular advantages of 3D reconstructed spiral scanning were seen in the planning of approaches to the lower clivus, acquired or congenital bony abnormalities and when the relationship between vessels, tumour and bone was important. (orig.)

  5. Synchronized control of spiral CT scan for security inspection device

    International Nuclear Information System (INIS)

    Wang Jue; Jiang Zenghui; Wang Fuquan

    2008-01-01

    In security inspection system of spiral CT, the synchronization between removing and rotating, and the scan synchronization between rotating and sampling influence quality of image reconstruction, so it is difficulty and important that how to realize synchronized scan. According to the controlling demand of multi-slice Spiral CT, the method to realize synchronized scan is given. a synchronized control system is designed, in which we use a industrial PC as the control computer, use magnetic grids as position detectors, use alternating current servo motor and roller motor as drivers respectively drive moving axis and rotating axis. This method can solve the problem of synchronized scan, and has a feasibility and value of use. (authors)

  6. Hybrid spectral CT reconstruction.

    Directory of Open Access Journals (Sweden)

    Darin P Clark

    Full Text Available Current photon counting x-ray detector (PCD technology faces limitations associated with spectral fidelity and photon starvation. One strategy for addressing these limitations is to supplement PCD data with high-resolution, low-noise data acquired with an energy-integrating detector (EID. In this work, we propose an iterative, hybrid reconstruction technique which combines the spectral properties of PCD data with the resolution and signal-to-noise characteristics of EID data. Our hybrid reconstruction technique is based on an algebraic model of data fidelity which substitutes the EID data into the data fidelity term associated with the PCD reconstruction, resulting in a joint reconstruction problem. Within the split Bregman framework, these data fidelity constraints are minimized subject to additional constraints on spectral rank and on joint intensity-gradient sparsity measured between the reconstructions of the EID and PCD data. Following a derivation of the proposed technique, we apply it to the reconstruction of a digital phantom which contains realistic concentrations of iodine, barium, and calcium encountered in small-animal micro-CT. The results of this experiment suggest reliable separation and detection of iodine at concentrations ≥ 5 mg/ml and barium at concentrations ≥ 10 mg/ml in 2-mm features for EID and PCD data reconstructed with inherent spatial resolutions of 176 μm and 254 μm, respectively (point spread function, FWHM. Furthermore, hybrid reconstruction is demonstrated to enhance spatial resolution within material decomposition results and to improve low-contrast detectability by as much as 2.6 times relative to reconstruction with PCD data only. The parameters of the simulation experiment are based on an in vivo micro-CT experiment conducted in a mouse model of soft-tissue sarcoma. Material decomposition results produced from this in vivo data demonstrate the feasibility of distinguishing two K-edge contrast agents with

  7. Hybrid spectral CT reconstruction

    Science.gov (United States)

    Clark, Darin P.

    2017-01-01

    Current photon counting x-ray detector (PCD) technology faces limitations associated with spectral fidelity and photon starvation. One strategy for addressing these limitations is to supplement PCD data with high-resolution, low-noise data acquired with an energy-integrating detector (EID). In this work, we propose an iterative, hybrid reconstruction technique which combines the spectral properties of PCD data with the resolution and signal-to-noise characteristics of EID data. Our hybrid reconstruction technique is based on an algebraic model of data fidelity which substitutes the EID data into the data fidelity term associated with the PCD reconstruction, resulting in a joint reconstruction problem. Within the split Bregman framework, these data fidelity constraints are minimized subject to additional constraints on spectral rank and on joint intensity-gradient sparsity measured between the reconstructions of the EID and PCD data. Following a derivation of the proposed technique, we apply it to the reconstruction of a digital phantom which contains realistic concentrations of iodine, barium, and calcium encountered in small-animal micro-CT. The results of this experiment suggest reliable separation and detection of iodine at concentrations ≥ 5 mg/ml and barium at concentrations ≥ 10 mg/ml in 2-mm features for EID and PCD data reconstructed with inherent spatial resolutions of 176 μm and 254 μm, respectively (point spread function, FWHM). Furthermore, hybrid reconstruction is demonstrated to enhance spatial resolution within material decomposition results and to improve low-contrast detectability by as much as 2.6 times relative to reconstruction with PCD data only. The parameters of the simulation experiment are based on an in vivo micro-CT experiment conducted in a mouse model of soft-tissue sarcoma. Material decomposition results produced from this in vivo data demonstrate the feasibility of distinguishing two K-edge contrast agents with a spectral

  8. Intracranial aneurysms: evaluation in 200 patients with spiral CT angiography

    International Nuclear Information System (INIS)

    Young, N.; Kingston, R.J.; Markson, G.; Dorsch, N.W.C.; McMahon, J.

    2001-01-01

    The goal of this study was to assess the usefulness of spiral CT angiography (CTA) with three- dimensional reconstructions in defining intracranial aneurysms, particularly around the Circle of Willis. Two hundred consecutive patients with angiographic and/or surgical correlation were studied between 1993 and 1998, with CTA performed on a GE HiSpeed unit and Windows workstation. The following clinical situations were evaluated: conventional CT suspicion of an aneurysm; follow-up of treated aneurysm remnants or of untreated aneurysms; subarachnoid haemorrhage (SAH) and negative angiography; family or past aneurysm history; and for improved definition of aneurysm anatomy. Spiral CTA detected 140 of 144 aneurysms, and an overall sensitivity of 97%, including 30 of 32 aneurysms 3 mm or less in size. In 38 patients with SAH and negative angiography, CTA found six of the seven aneurysms finally diagnosed. There was no significant artefact in 17 of 23 patients (74%) with clips. The specificity of CTA was 86% with 8 false-positive cases. Spiral CTA is very useful in demonstrating intracranial aneurysms. (orig.)

  9. Optimising imaging parameters in experimental spiral CT

    International Nuclear Information System (INIS)

    Tiitola, M.; Vehmas, T.; Kivisaari, R.P.; Kivisaari, L.

    1997-01-01

    Purpose: This in vitro study was conducted to analyse lesion detection and relative radiation exposure in different CT techniques. Material and Methods: We used a plastic phantom (12 x 8 x 2 cm) containing holes filled with air or fluid of varying densities to simulate lesions. This was imaged with Siemens Somatom Plus S and GE High Speed Advantage units. We varied table feeds (3 and 6 mm/s in Siemens and 3 and 4.5 mm/s in GE) and increments (2 mm and 4 mm) while keeping collimation at 3 mm. The SmartScan program of GE and the reformating algorithm of Siemens were also analysed. To evaluate the different methods, the phatnom lesions were counted by 3 observers. Radiation exposures associated with each technique were also measured. Results: The images reformatted to a coronal direction were significantly inferior (p<0.01) to those in other techniques. The use of SmartScan did not influence lesion detection, nor did changes in pitch or increment. Spiral and non-spiral techniques proved to be equal. Radiation exposure was lowest when a greater pitch or the SmartScan program was used. Conclusion: Radiation exposure in CT can be limited without significantly impairing the image quality by using low-dose techniques. Reformatting to a coronal direction should be used with care as it debases the image quality. (orig.)

  10. Virtual gastroscopy using spiral CT in gastric lesions

    International Nuclear Information System (INIS)

    Shin, Sang Soo; Kang, Heoung Keun; Jeong, Yong Yeon; Yoon, Man Won; Song, Sang Gook; Jeong, Gwang Woo

    1998-01-01

    To compare virtual gastroscopy using spiral CT with conventional endoscopy for the detection and evaluation of gastric lesions. During a previous six-month period, 30 patients with pathologically-proven gastric lesions underwent conventional endoscopy and virtual gastroscopy using spiral CT. There were 18 cases of advanced gastric carcinoma, eight benign ulcers, and four submucosal tumors(two leiomyomas, two lymphomas). Source images of virtual gastroscopy were three-dim-ensionally reconstructed within an Advantage Windows Workstation and virtual gastroscopic images were obtained using Navigator Software. On analysis, images were graded according to their quality(excellent, good, poor). Virtual gastroscopic images were interpreted by two radiologists blinded to conventional endoscopic findings, and were subsequently compared with endoscopic findings in terms of detectability and findings. In the cases of advanced gastric carcinoma, lesions were classified according to Borrmann's system. For virtual gastroscopy, overall image quality was excellent in 21 cases(70%), good in five(17%), and poor in four(13%). Lesions were detected in 25 cases(83%). Among the 18 advanced gastric carcinomas, virtual gastroscopy image quality was excellent in 14 cases(78%), good in two(11%), and poor in two(11%). Lesions were detected in 16 cases(89%). Two Borrmann type IV cases were not detected. Among the eight benign ulcers, virtual gastroscopy image quality was excellent in three cases(38%), good in three(38%), and poor in two(25%). The detection of lesion was possible in five cases(63%). In all submucosal tumors, virtual gastroscopy image quality was excellent. Lesions were detected in all cases. Virtual gastroscopy using spiral CT is safe and noninvasive, and for the evaluation of gastric lesions may be complementary to axial CT. It successfully detects gastric lesions, and in depicting the pattern of gastric folds its image quality is excellent.=20

  11. Cerebral av angiomas: 3-dimensional demonstration by spiral CT

    International Nuclear Information System (INIS)

    Rieger, J.; Hosten, N.; Neumann, K.; Lemke, A.J.; Langer, R.; Lanksch, W.R.; Pfeifer, K.J.; Felix, R.

    1994-01-01

    In 20 patients with known or suspected supratentorial arteriovenous malformations, an attempt was made to see how far CT angiography with 3-dimensional reconstructions is able to make a diagnosis and to differentiate the various components of the angioma. Spiral CT was performed following an intravenous bolus injection of 60-80 ml of iodine containing contrast medium. In all patients the diagnosis was confirmed by intra-arterial DSA of the vertebral vessels. In 13 patients, av malformations could be diagnosed following multiplanar 3-D reconstructions which agreed with the findings on DSA. The large supplying vessels, the nidus and the large draining veins could be defined with certainty. In 6 patients follow-up examination after embolisation was performed. The results could be demonstrated in three dimensions and the success of treatment could be documented unequivocally. CT angiography with 3-D reconstruction is able to supply important information in the majority of intracranial av malformations, both during initial investigation and following treatment. (orig.) [de

  12. Spiral CT: An innovative method of volumetric recording. Pt. 1

    International Nuclear Information System (INIS)

    Kalender, W.A.; Vock, P.; Polacin, A.; Soucek, M.

    1990-01-01

    A major advance in the field of CT diagnosis has been made with the development of spiral computed tomography. It permits a complete photographic recording of volumes in such a way that even 'minor' pathological changes can be detected and reconstructed providing the absence of respiration-induced organ displacement. During one session, in which up to 24 360deg scans may be obtained within 24 seconds, the patient is continuously shifted at a speed of 10 mm/s, which permits the volumes recorded to be increased up to a height of 24 cm. The underlying methodology is described, as is the procedure to be used in the reconstruction of planar pictures from the volumes recorded. (orig./GDG) [de

  13. Measurement of slice sensitivity profile for a 64-slice spiral CT system

    International Nuclear Information System (INIS)

    Liu Chuanya; Qin Weichang; Wang Wei; Lu Chuanyou

    2006-01-01

    Objective: To measure and evaluate slice sensitivity profile (SSP) and the full width at half-maximum(FWHM) for a 64-slice spiral CT system. Methods: Using the same CT technique and body mode as those used for clinical CT, delta phantom was scanned with Somatom Sensation 64-slice spiral CT. SSPs and FWHM were measured both with reconstruction slice width of 0.6 mm at pitch=0.50, 0.75, 1.00, 1.25, 1.50 and with reconstruction slice width of 0.6, 1.0, 1.5 mm at pitch=1 respectively. Results: For normal slice width of 0. 6 mm, the measured FWHM, i.e. effective slice width, is 0.67, 0.67, 0.66, 0.69, 0.69 mm at different pitch. All the measured FWHM deviate less than 0.1 mm from the nominal slice width. The measured SSPs are symmetrical, bell-shaped curves without far-reaching tails, and show only slight variations as a function of the spiral pitch. When reconstruction slice width increase, relative SSP become wider. Conclusions: The variation of pitch hardly has effect all on SSP, effective slice width, and z-direction spatial resolution for Sensation 64-slice spiral CT system, which is helpful to optimize CT scanning protocol. (authors)

  14. Spiral CT scanning plan to generate accurate Fe models of the human femur

    International Nuclear Information System (INIS)

    Zannoni, C.; Testi, D.; Capello, A.

    1999-01-01

    In spiral computed tomography (CT), source rotation, patient translation, and data acquisition are continuously conducted. Settings of the detector collimation and the table increment affect the image quality in terms of spatial and contrast resolution. This study assessed and measured the efficacy of spiral CT in those applications where the accurate reconstruction of bone morphology is critical: custom made prosthesis design or three dimensional modelling of the mechanical behaviour of long bones. Results show that conventional CT grants the highest accuracy. Spiral CT with D=5 mm and P=1,5 in the regions where the morphology is more regular, slightly degrades the image quality but allows to acquire at comparable cost an higher number of images increasing the longitudinal resolution of the acquired data set. (author)

  15. In-vitro studies to determine the degree of stenosis using spiral-CT angiography

    International Nuclear Information System (INIS)

    Wittenberg, G.; Lenk, G.; Jenett, M.; Elsner, H.; Kaiser, W.A.; Kellner, M.; Schultz, G.; Trusen, A.; Hahn, D.

    1998-01-01

    Purpose: Aim of the study was to evaluate the influence of different spiral-CT parameters for the visualisation of vascular stenoses, especially of the renal arteries. Material and methods: Models with a density equivalent to that of fat, filled with diluted contrast agent, and an inner lumen of 4, 6, 8 mm were scanned in x-, y- and z-direction. Data were acquired in up to 24 second long spiral-CT scans using different spiral-CT parameters (collimation, table speed, reconstruction algorithm, tube current). Detection of the degree of stenosis was achieved by assessment of the axial images and 3D reconstructions. Results: The best correlation between real and measured degree of stenosis was seen by using a small collimation, a low table increment and assessment of the axial images reconstructed in standard algorithm. The stenosis degrees of models directed in x- and y-direction were overestimated and those in z-direction were underestimated depending on the spiral-CT parameters. Conclusion: For optimal imaging of renal artery stenoses, collimation of 2 mm (pitch=1-2) and a reconstruction interval of 1 mm is recommended. (orig.) [de

  16. Borrmann type IV adenocarcinoma versus gastric lymphoma : spiral CT evaluation

    International Nuclear Information System (INIS)

    Seo, Bo Kyoung; Kim, Yun Hwan; Shin, Kue Hee; Hong, Suk Joo; Kim, Hong Weon; Park, Cheol Min; Chung, Kyoo Byung; Cho, Hyun Deuk

    1999-01-01

    To distinguish the spiral CT findings of Borrmann type IV adenocarcinoma from those of gastric lymphoma with diffuse gastric wall thickening. We retrospectively reviewed the spiral CT scans of 30 patients with Borrmann type IV adenocarcinoma and nine with gastric lymphoma with diffuse gastric wall thickening. In all patients the respective condition was pathologically confirmed by gastrectomy. CT scanning was performed after peroral administration of 500-700ml of water. A total of 120-140 ml bolus of nonionic contrast material was administered intravenously at a flow rate of 3 ml/sec and two-phase images were obtained at 35-45 sec(early phase) and 180 sec(delayed phase) after the start of bolus injection. Spiral CT was performed with 10mm collimation, 10mm/sec table feed and 10mm reconstruction. We evaluated the degree and homogeneity of enhancement of thickened entire gastric wall, and the enhancement pattern of gastric inner layer, as seen on early-phase CT scans. On early and delayed views, the thickness of gastric wall and the presence of perigastric fat infiltration were determined. The enhancement patterns of gastric inner layer were classified as either continuous or discontinuous thick enhancement, thin enhancement, or nonenhancement. The thickness of gastric wall was 1.2-3.5cm(mean 2.2cm) in cases of adenocarcinoma and 1.2-7.6cm(mean 4cm) in lymphoma. Perigastric fat infiltration was seen in 24 patients with adenocarcinoma(80%) and four with lymphoma(44%). In those with adenocarcinoma, the degree of enhancement of entire gastric wall was hyperdense in fifteen patients(50%) and isointense in eleven (37%). Seven patients with lymphoma(78%)showed hypodensity. In those with adenocarcinoma, continuous thick enhancement of gastric inner layer was seen in 18 patients(60%) and discontinuous thick enhancement in nine(30%). In lymphoma cases, no thick enhancement was observed. Thin enhancement of gastric inner layer was demonstrated in three patients with

  17. General surface reconstruction for cone-beam multislice spiral computed tomography

    International Nuclear Information System (INIS)

    Chen Laigao; Liang Yun; Heuscher, Dominic J.

    2003-01-01

    A new family of cone-beam reconstruction algorithm, the General Surface Reconstruction (GSR), is proposed and formulated in this paper for multislice spiral computed tomography (CT) reconstructions. It provides a general framework to allow the reconstruction of planar or nonplanar surfaces on a set of rebinned short-scan parallel beam projection data. An iterative surface formation method is proposed as an example to show the possibility to form nonplanar reconstruction surfaces to minimize the adverse effect between the collected cone-beam projection data and the reconstruction surfaces. The improvement in accuracy of the nonplanar surfaces over planar surfaces in the two-dimensional approximate cone-beam reconstructions is mathematically proved and demonstrated using numerical simulations. The proposed GSR algorithm is evaluated by the computer simulation of cone-beam spiral scanning geometry and various mathematical phantoms. The results demonstrate that the GSR algorithm generates much better image quality compared to conventional multislice reconstruction algorithms. For a table speed up to 100 mm per rotation, GSR demonstrates good image quality for both the low-contrast ball phantom and thorax phantom. All other performance parameters are comparable to the single-slice 180 deg. LI (linear interpolation) algorithm, which is considered the 'gold standard'. GSR also achieves high computing efficiency and good temporal resolution, making it an attractive alternative for the reconstruction of next generation multislice spiral CT data

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

    International Nuclear Information System (INIS)

    Chung, Kyung Il; Park, Kyung Ju; Lee, Eh Hyung; Yune, Heun Young; Suh, Jung Ho; Choe, Kyu Ok; Lim, Tae Hwan; Chung, In Hyuk

    1996-01-01

    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

  19. Lung studies with spiral CT. pitch 1 versus pitch 2

    International Nuclear Information System (INIS)

    Sartoni Galloni, S.; Miceli, M.; Lipparino, M.; Burzi, M.; Gigli, F.; Rossi, M.S.; Santoli, G.; Guidarelli, G.

    1999-01-01

    In Spiral CT, the pitch is the ratio of the distance to tabletop travels per 360 degrees rotation to nominal slice width, expressed in mm. Performing Spiral CT examination with pitch 2 allows to reduce examination time, exposure and contrast dose, and X-ray tube overload. The authors investigated the yield of pitch 2 in lung parenchyma studies, particular relative to diagnostic image quality [it

  20. Negative spiral CT in acute pulmonary embolism

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, T.; Olausson, A. [Karolinska Hospital, Stockholm (Sweden). Dept. of Thoracic Radiology; Johnsson, H. [Karolinska Hospital, Stockholm (Sweden). Dept. of Internal Medicine; Nyman, U. [County Hospital, Trelleborg (Sweden). Dept. of Radiology; Aspelin, P. [Huddinge Univ. Hospital (Sweden). Dept. of Radiology

    2002-09-01

    Purpose: To retrospectively evaluate the clinical outcome of non-anticoagulated patients with clinically suspected acute pulmonary embolism (PE) and no symptoms or signs of deep venous thrombosis (DVT) following a negative contrast medium-enhanced spiral CT of the pulmonary arteries (s-CTPA). Material and Methods: During a 24-month period, 739 of 751 patients underwent s-CTPA with acceptable diagnostic quality for clinically suspected acute PE. All patients who had a CT study not positive for PE were followed up with a questionnaire, a telephone interview and review of all medical reports, including autopsies and death certificates for any episodes of venous thromboembolism (VTE) during a 3-month period. Results: PE was diagnosed in 158 patients. Of the remaining 581 patients with a negative s-CTPA, 45 patients were lost to follow-up. 88 patients were excluded because of anticoagulation treatment (cardiac disorder n=32, chronic VTE or acute symptomatic DVT n=31, PE diagnosed at pulmonary angiography n=1, thrombus prophylaxis during diagnostic work-up or other reasons than VTE n=24) and 7 patients undergoing lower extremity venous studies because of symptoms of DVT (all negative). Thus, 441 patients with a negative s-CTPA and no DVT symptoms, venous studies or anticoagulant treatment constituted the follow-up cohort. Four of these patients had proven VTE (all PE) during the 3-month follow-up period. Two of the PE episodes contributed to the patient's death. Conclusion: Patients with clinically suspected acute PE, no symptoms or signs of DVT and a negative single slice s-CTPA using 3-5 mm collimation, may safely be left without anticoagulation treatment unless they are critically ill, have a limited cardiopulmonary reserve and/or if a high clinical suspicion remains.

  1. Preoperative evaluation of the abdominal aortic aneurysm using spiral CT

    International Nuclear Information System (INIS)

    Chisuwa, Hisanao; Nishimaki, Keiji; Arai, Masayuki; Honda, Haruyasu; Urata, Koichi; Miyagawa, Yusuke; Makuuchi, Masatoshi; Shimizu, Mikio; Okamoto, Kohei.

    1995-01-01

    Six patients with abdominal aortic aneurysm (AAA) were studied with three-dimensionally reconstructed CT angiography (3D-CTA) in order to evaluate its usefulness as a diagnostic tool for vascular surgery patients. Images of the intravenously contrasted abdominal aorta were obtained with spiral scan during a single breath hold. The images of the abdominal aorta and its major branches were three-dimensionally reconstructed with a shaded surface display mode. The three-dimensional image reconstruction was successful in all the six cases and performed without difficulties. Shaded surface display presented a deficit to depict the aortic wall with mural thrombus. However, multidirectional display of the abdominal aorta and its branches facilitated interpretation of the anatomical details of the lesions and planning of surgical repair. 3D-CTA is an alternative to conventional aortography for preoperative diagnosis of AAA. Moreover it was shown to be noninvasive, easy to proceed. It presented good angiographical resolution that can be used as a precise diagnostic tool in vascular surgery. (author)

  2. Spiral CT portography: correlation with different injection rate

    International Nuclear Information System (INIS)

    Wu Dong; Zhou Kangrong; Chen Zuwang; Chen Gang; Chen Jin; Chen Huiming

    2000-01-01

    Objective: To choose optimal injection rate in spiral CT portography(CTP) by comparing 3D CTP images using different injection rates. Methods: Thirty-seven patients were randomly divided into 2 groups (11 and 26 cases in each group). Single-level dynamic scan was completed at the first liver hilus, starting at 15s or 30s after initial contrast injection(2 ml/kg) with injection rate 1.5 ml/s (slow group) or 3.0 ml/s (rapid group). The continuous scan were repeated every 5s for 120s or 135s. ROI was used to measure the CT value of the portal vein and the liver parenchyma, respectively, and then the time-density curves were drawn. Spiral CT portography were performed at injection rate of 1.5 ml/s or 3.0 ml/s as the delay time designed described above, including 98 cases in rapid group and 12 cases in slow group. Both MPVR (multi-projection volume reconstruction) and MIP (maximum intensity projection) were employed for reconstruction. All images were ranked according to the grade of portal vein, the different CT value between the portal vein and the liver parenchyma, the edge's definition of blood vessel, the grade of hepatic vein and the display of IVC by 2 radiologists. Results: The maximum density difference in average between the portal vein and the liver parenchyma was 53.4 HU and 83.9 HU, respectively (t = 16.418, P < 0.001) in slow group and rapid one, and the mean reaching time was 80s and 60s, respectively (t = 13.394, P < 0.001). In slow injection group, the average score of MPVR image was 9.3, while it was 12.5 (t = 3.514, P < 0.01) in rapid injection group. Rapid group was better than slow one at the PV-L, the grade of the portal vein, and the edge's definition of blood vessel. Conclusion: Using rapid injection rate (3.0 ml/s), the maximum density difference between the portal vein and the liver parenchyma increases, and the mean reaching time shortens. The quality of 3D CTP image of rapid injection rate (3.0 ml/s) is superior to that of slow injection rate

  3. A study of parameters in spiral CT volumetry using balloon phantoms

    International Nuclear Information System (INIS)

    Lee, Hak Jong; Han, Joon Koo

    2001-01-01

    To evaluate the effects of threshold values, reconstruction interval, slice thickness and table speed on the spiral CT volumetry. Two phantoms made of a balloon and diluted contrast media underwent spiral CT scanning with section thicknesses of 5, 7 and 10 mm and table speeds of 5, 8 and 10 mm with scans of 5 mm section thickness, 7, 10, and 14 mm with scans of 7 mm section thickness, and 10, 15, and 20 mm with scans of 10 mm section thickness. The volumetric values of phantom A and B were obtained at varying threshold values and a reconstruction interval of 5 and 10 mm for all scans. Volumes were also determined with the threshold value fixed and a reconstruction interval of 1, 5, 7 and 10 mm, respectively. Three-dimensional display and volumetric measurements were obtained using reconstructed images. The effects of threshold value, reconstruction interval, slice thickness and table speed on volumetry were analyzed. Volumetric values varied according to threshold values. Where a threshold value was low, value increased as pitch increased, but where a the threshold value was high, value decreased as pitch increased. With varying threshold values, measurement errors in CT volumetry were 1.6 to 9.0%. Volume decreased as reconstruction interval increased. Where the table speed/ slice thickness ratio was constant, volume was constant though slice thickness differed. At fixed threshold values, variation in the reconstruction interval was statistically more significant than variation in slice thickness or table speed (p<0.05, Kruskal-Wallis one-way ANOVA). Among serveral spiral scanning and image reconstruction parameters including threshold value, reconstruction interval, slice thickness, and table speed, threshold value most affected the result obtained. At fixed threshold values, the reconstruction interval used had more effect on CT volumetry than other parameters

  4. 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

    -ferrous metal of low atomic number that allows very clear CT and MR images to be obtained. Further Ti features are strength, biocompatibility and easy handling. 3D Helical CT scan has proven to be the most complete and accurate imaging technique for reconstructive plastic surgery with alloplastic material in advanced maxillofacial cancer, also considering the anatomic and functional complexity of his area. The prospect is provided to identify virtual 3D presurgical ablation planes. These may allow the surgeon to improve plastic reconstruction and shorten intervention time. [Italian] Scopo di questo articolo e' quello di analizzare il ruolo della TC spirale e i vantaggi delle ricostruzioni tridimensionali di superficie nella pianificazione e controllo degli interventi di chirurgia ricostruttiva plastica con materiale alloplastico nelle neoplasie maligne del massiccio facciale. Sono state eseguite dal 1996 al 1999 11 ricostruzioni plastiche dell'osso mascellare per neoplasie osteodestruenti il massiccio facciale utilizzando materiale alloplastico. Per la ricostruzione della parete anteriore dell'osso mascellare e del pavimento orbitario e' stata utlizzata una rete di titanio al 100% modulabile. Applicato nel cavo residuo dell'osso un otturatore siliconato sormontante una protesi acrilica con arcata dentaria per la ricostruzione del palato. In due casi utilizzato pericardio bovino modulato sulla soluzione di continuo. Tutti i pazienti sono stati studiati con TC spirale sia nella fase preoperatoria che entro il sesto mese dall'intervento chirurgico. Elaborate ricostruzioni tridimensionali della superficie (shaed surface display-SSD) con valori soglia compresi tra 425 e 630 UH ma con intervallo piu' stretto di finestra sui valori UH all'interfaccia osso/rete di titanio nei controlli del modellamento protesico. L'elaborazione tridimensionale della superificie sui dati ottenuti con acquisizione volumetrica ha fornito in tutti casi la fedele

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  6. Spiral CT findings of inflammatory pseudotumor of the liver

    International Nuclear Information System (INIS)

    Lee, Ha Jong; Nam, Kyung Jin; Lee, Ki Nam; Park, Byeong Ho; Choi, Jong Cheol; Koo, Bong Sik; Nam, Ki Dong; Kim, Chan Seong

    1998-01-01

    To assess the spiral CT findings of inflammatory pseudotumor of the liver(IPTL), in order to distinguish this tumor from hepatocellular carcinoma, hepatic abscess or other space occupying liver lesions. The spiral CT findings of IPTL were retrospectively evaluated in six patients. All cases were confirmed by ultrasonography-guided gun biopsy. Four patients were men and two were women, and they were aged between 37 and 74 (mean, 49) years. The site, size, and number of IPTL were assessed, and their enhancement patterns were evaluated during the arterial, portal and delayed phases of spiral CT. Five cases involved a solitary mass and in one there were multiple masses with surrounding small nodules. Four cases occurred in the right lobe and two in the left lobe. Four of five surrounding nodules were in the left lobe. During the arterial phase of spiral CT scanning, three layers were separated from four of five cases of solitary mass;they were composed of central and peripheral portions of low attenuation, and an intermediate portion of isoattenuation. Delayed enhancement of the peripheral portion was prominent during the delayed phase. In the case involving multiple masses three layers were not seen during the arterial phase, but during the delayed phase enhancement was noted. The features of three layers, as seen on spiral CT, is considered to be very specific for distinguishing IPTL from other hepatic focal lesions.=20

  7. Application of multislice spiral CT in children urinary tract injuries

    International Nuclear Information System (INIS)

    Feng Hui; Chen Jing

    2012-01-01

    Objective: To investigate the application value of three-dimensional reconstruction technique of multislice spiral CT(MSCT) in children urinary tract injuries. Methods: Forty-three patients with urinary tract injury performed MSCT scan, and three-dimensional reconstruction technique was used for volume rendering, maximum intensity projection and multi-planar reformation, urinary tract imaging was acquired completely. The images were reviewed by two experienced radiologists. Results: Of the 43 cases,there were 5 simple contusion of kidney, 5 contusion and laceration of kidney accompanied with subcapsular haematoma, 4 contusion and laceration of kidney accompanied with perinephric haematoma, 2 contusion and laceration of kidney accompanied with adrenal haematoma, 13 shattered kidney accompanied with extravasation of urine, 3 shattered kidney accompanied with renal pedicle injury, 6 shattered kidney accompanied with ureter injury, 2 pelvic fracture accompanied with posterior urethra split, 3 contusion of urinary bladder wall accompanied with blood clot in the urinary bladder. Conclusion: MSCT has the characteristic of high scanning speed, wide overlay scope,high image quality and thin slice scan. It is an effective modality in the evaluation of children urinary tract injuries. (authors)

  8. Vascular imaging with spiral CT. The way to CY angiography

    International Nuclear Information System (INIS)

    Prokop, M.; Schaefer, C.; Kalender, W.A.; Polacin, A.; Galanski, M.

    1993-01-01

    Spiral CT is a technique that allows for high-quality two-dimensional angiographic projections and 3D imaging of vascular structures. The authors present the technical and methodological principles of the technique, including scan parameters and parameters of contrast application for various clinical imaging tasks. They present their experience with over 150 clinical cases using spiral CT angiography. Suitable applications of this technique include cogenital anomalies, aneurysms, dissections, stenoses, thrombi and vascular tumor involvement. Given a problem-adapted examination technique, pathologic changes in vessels of as little as 2 mm can be visualized. In some cases with complex vascular anatomy, spiral CT angiography can be superior to arterial angiography. (orig.) [de

  9. The potentials of spiral CT for detection of focal liver lesions; Moeglichkeiten der Spiral-CT zur Diagnostik fokaler Leberlaesionen

    Energy Technology Data Exchange (ETDEWEB)

    Helmberger, H. [Technische Univ. Muenchen, Klinikum rechts der Iser, Inst. fuer Roentgendiagnostik (Germany); Kersting-Sommerhoff, B. [Technische Univ. Muenchen, Klinikum rechts der Iser, Inst. fuer Roentgendiagnostik (Germany); Lenz, M. [Technische Univ. Muenchen, Klinikum rechts der Iser, Inst. fuer Roentgendiagnostik (Germany); Kirsten, R. [Technische Univ. Muenchen, Klinikum rechts der Iser, Inst. fuer Roentgendiagnostik (Germany); Bautz, W. [Technische Univ. Muenchen, Klinikum rechts der Iser, Inst. fuer Roentgendiagnostik (Germany)

    1996-03-01

    Spiral CT currently is the modality of choice for all aspects of diagnostic evaluation of the liver. Optimal selection of treatment should be based inter alia on the findings obtained by spiral CT with arterial application of contrast medium, as for example S-CTA (primary liver tumors), or S-CTAP (secondary liver tumors). Ultrasonography is the major supplementing modality. In the near future, MR imaging applying liver-specific contrast-enhancing agents is expected to become an important competing technique, and further developments of interest in diagnostic imaging of the liver are in the offing: it is not yet known which technique will be the modality of choice at the onset of the 21st century. (orig.) [Deutsch] Die Spiral-CT ist zur Zeit das empfehlenswerte Verfahren fuer alle Fragen der Leberdiagnostik. Zur optimalen praetherapeutischen Beurteilung der Leber sollte die Spiral-CT mit arterieller Kontrastmittelapplikation als S-CTA (primaere Lebertumoren) bzw. S-CTAP (sekundaere Lebertumoren) durchgefuehrt werden. Der US kommt ein Stellenwert als ergaenzende Methode zu. In Zukunft wird die MRT mit leberspezifischen Kontrastmitteln ein konkurrierendes Verfahren zur Spiral-CT darstellen, wobei eine weitere interessante Entwicklung auf dem Gebiet der hepatischen Bildgebung zu erwarten ist: Das diagnostische Verfahren der Wahl fuer die Leber zu Beginn des 21. Jahrhunderts ist noch nicht definiert. (orig.)

  10. Advanced single-slice rebinning for tilted spiral cone-beam CT

    International Nuclear Information System (INIS)

    Kachelriess, Marc; Fuchs, Theo; Schaller, Stefan; Kalender, Willi A.

    2001-01-01

    Future medical CT scanners and today's micro CT scanners demand cone-beam reconstruction algorithms that are capable of reconstructing data acquired from a tilted spiral trajectory where the vector of rotation is not necessarily parallel to the vector of table increment. For the medical CT scanner this case of nonparallel object motion is met for nonzero gantry tilt: the table moves into a direction that is not perpendicular to the plane of rotation. Since this is not a special application of medical CT but rather a daily routine in head exams, there is a strong need for corresponding reconstruction algorithms. In contrast to medical CT, where the special case of nonperpendicular motion is used on purpose, micro CT scanners cannot avoid aberrations of the rotational axis and the table increment vector due to alignment problems. Especially for those micro CT scanners that have the lifting stage mounted on the rotation table (in contrast to setups where the lifting stage holds the rotation table), this kind of misalignment is equivalent to a gantry tilt. We therefore generalize the advanced single-slice rebinning algorithm (ASSR), which is considered a very promising approach for medical cone-beam reconstruction due to its high image quality and its high reconstruction speed [Med. Phys. 27, 754-772 (2000)], to the case of tilted gantries. We evaluate this extended ASSR approach (which we will denote as ASSR + , for convenience) in comparison to the original ASSR algorithm using simulated phantom data for reconstruction. For the case of nonparallel object motion ASSR + shows significant improvements over ASSR, however, its computational complexity is slightly increased due to the broken symmetry of the spiral trajectory

  11. Application of CT three-dimensional reconstruction in elbow injury

    International Nuclear Information System (INIS)

    Liang Wenhua; Qian Li

    2009-01-01

    Objective: To investigate the application of multi-slice spiral CT in fracture of elbow, and to study the value of different methods of the reconstruction. Methods: Thin line cross-section spiral CT scan was carried out in 13 cases with elbow injury, three-dimensional reconstruction was completed later. Several reconstructed image quality to display f the elbow fracture and dislocation were analyzed and compared. Results: 13 cases (17) elbow trauma included humeral media epicondyle fracture, humeral external epicondyle fracture, intercondylar fracture, olecranal fracture and radial head fracture. Among them, X-ray film showed negative in three sites, showed suspect fractures in 2 cases, and only showed single fracture in 2 cases. MPR reconstruction image could not only identify the diagnosis of fracture, but also provide further multi-angle display on fracture line and the extent of articular surface involvement. Surface reconstruction technology could exclude the impact of passive elbow flexion and display elbow injury more intuitively. Conclusion The elbow fracture dislocation could be showed clearly in multi-slice spiral CT, especially for complex fractures, with unmatched advantages compared to X-ray for clinical diagnosis and treatment determination. (authors)

  12. Measurement error of spiral CT volumetry: influence of low dose CT technique

    International Nuclear Information System (INIS)

    Chung, Myung Jin; Cho, Jae Min; Lee, Tae Gyu; Cho, Sung Bum; Kim, Seog Joon; Baik, Sang Hyun

    2004-01-01

    To examine the possible measurement errors of lung nodule volumetry at the various scan parameters by using a small nodule phantom. We obtained images of a nodule phantom using a spiral CT scanner. The nodule phantom was made of paraffin and urethane and its real volume was known. For the CT scanning experiments, we used three different values for both the pitch of the table feed, i.e. 1:1, 1:15 and 1:2, and the tube current, i.e. 40 mA, 80 mA and 120 mA. All of the images acquired through CT scanning were reconstructed three dimensionally and measured with volumetry software. We tested the correlation between the true volume and the measured volume for each set of parameters using linear regression analysis. For the pitches of table feed of 1:1, 1:1.5 and 1:2, the mean relative errors were 23.3%, 22.8% and 22.6%, respectively. There were perfect correlations among the three sets of measurements (Pearson's coefficient = 1.000, p< 0.001). For the tube currents of 40 mA, 80 mA and 120 mA, the mean relative errors were 22.6%, 22.6% and 22.9%, respectively. There were perfect correlations among them (Pearson's coefficient=1.000, p<0.001). In the measurement of the volume of the lung nodule using spiral CT, the measurement error was not increased in spite of the tube current being decreased or the pitch of table feed being increased

  13. Comparison of Conventional Versus Spiral Computed Tomography with Three Dimensional Reconstruction in Chronic Otitis Media with Ossicular Chain Destruction

    International Nuclear Information System (INIS)

    Naghibi, Saeed; Seifirad, Sirous; Adami Dehkordi, Mahboobeh; Einolghozati, Sasan; Ghaffarian Eidgahi Moghadam, Nafiseh; Akhavan Rezayat, Amir; Seifirad, Soroush

    2016-01-01

    Chronic otitis media (COM) can be treated with tympanoplasty with or without mastoidectomy. In patients who have undergone middle ear surgery, three-dimensional spiral computed tomography (CT) scan plays an important role in optimizing surgical planning. This study was performed to compare the findings of three-dimensional reconstructed spiral and conventional CT scan of ossicular chain study in patients with COM. Fifty patients enrolled in the study underwent plane and three dimensional CT scan (PHILIPS-MX 8000). Ossicles changes, mastoid cavity, tympanic cavity, and presence of cholesteatoma were evaluated. Results of the two methods were then compared and interpreted by a radiologist, recorded in questionnaires, and analyzed. Logistic regression test and Kappa coefficient of agreement were used for statistical analyses. Sixty two ears with COM were found in physical examination. A significant difference was observed between the findings of the two methods in ossicle erosion (11.3% in conventional CT vs. 37.1% in spiral CT, P = 0.0001), decrease of mastoid air cells (82.3% in conventional CT vs. 93.5% in spiral CT, P = 0.001), and tympanic cavity opacity (12.9% in conventional CT vs. 40.3% in spiral CT, P=0.0001). No significant difference was observed between the findings of the two methods in ossicle destruction (6.5% conventional CT vs. 56.4% in spiral CT, P = 0.125), and presence of cholesteatoma (3.2% in conventional CT vs. 42% in spiral CT, P = 0.172). In this study, spiral CT scan demonstrated ossicle dislocation in 9.6%, decrease of mastoid air cells in 4.8%, and decrease of volume in the tympanic cavity in 1.6%; whereas, none of these findings were reported in the patients' conventional CT scans. Spiral-CT scan is superior to conventional CT in the diagnosis of lesions in COM before operation. It can be used for detailed evaluation of ossicular chain in such patients

  14. Spiral CT angiography of renal arteries: comparison with angiography

    International Nuclear Information System (INIS)

    Wittenberg, G.; Kenn, W.; Tschammler, A.; Sandstede, J.; Hahn, D.

    1999-01-01

    A prospective study was carried out to determine the accuracy of spiral CT angiography (CTA) in the detection of renal artery stenosis (RAS). Eighty-two patients with arterial hypertension underwent CTA and digital subtraction angiography (DSA) to exclude RAS. For CTA a contrast medium bolus of 100-150 ml (flow rate 3 ml/s) was injected. A 24 or 40 s CTA was started at the origin of the superior mesenteric artery after a delay time determined by test bolus injection (collimation = 2 mm, pitch = 1/1.5). For stenosis detection transverse images supported by maximum intensity projections (MIP) or multiplanar reconstruction projections were used. Of 197 renal arteries examined (including 33 accessory arteries), 34 RAS were visualized using DSA. With CTA, one hemodynamic RAS was missed and one additional hemodynamic RAS was found. Sensitivity/specificity was calculated to be 94 %/98 %. For hemodynamically relevant RAS (> 50 %) the sensitivity/specificity was 96 %/99 %. CTA additionally depicted five adrenal masses. The high accuracy rate of RAS detection thus allows the use of CTA as a screening method in patients with arterial hypertension to exclude a renovascular cause. (orig.)

  15. Value of noncontrast spiral CT for suspected acute appendicitis

    International Nuclear Information System (INIS)

    Choi, Pil Yeob; Lee, Sang Wook; Kwon, Jae Soo; Sung, Young Soon; Rho, Myoung Ho; Chang, Jeong A.

    1998-01-01

    To assess the diagnostic accuracy and clinical efficacy of noncontrast spiral CT in patients with suspected acute appendicitis. Over a six-month period, 100 patients with suspected acute appendicitis were prospectively evaluated with noncontrast spiral CT. All scans were obtained from the lower body of L3 to the symphysis pubis, with 5mm or 10mm collimation and pitch of 1 or 1.5, and without intravenous or oral contrast material. Diagnosis was established by means of surgical or clinical follow-up. Prospective diagnosis based on CT findings was compared with surgical results and clinical follow-up. Acute appendicitis was confirmed in 47 of 100 patients. On the basis of the Ct findings, SI patients were prospectively interpreted as positive for appendicitis, but in six the diagnosis was false-positive. Two of the 47 with acute appendicitis were prospectively interpreted as normal. The preoperative diagnosis of acute appendicitis was, thus, 45 true-positive, 47 true-negative, six false-positive and two false-negative yielding a sensitivity of 96%, a specificity of 89%, an accuracy of 92%, a positive predictive value of 88%, and a negative predictive value of 96%. Using CT, an alternative diagnosis was established in 14 patients. Noncontrast spiral CT is a useful technique for diagnosing acute appendicitis. =20

  16. Staging of gastric adenocarcinoma using two-phase spiral CT: correlation with pathologic staging

    International Nuclear Information System (INIS)

    Seo, Tae Seok; Lee, Dong Ho; Ko, Young Tae; Lim, Joo Won

    1998-01-01

    To correlate the preoperative staging of gastric adenocarcinoma using two-phase spiral CT with pathologic staging. One hundred and eighty patients with gastric cancers confirmed during surgery underwent two-phase spiral CT, and were evaluated retrospectively. CT scans were obtained in the prone position after ingestion of water. Scans were performed 35 and 80 seconds after the start of infusion of 120mL of non-ionic contrast material with the speed of 3mL/sec. Five mm collimation, 7mm/sec table feed and 5mm reconstruction interval were used. T-and N-stage were determined using spiral CT images, without knowledge of the pathologic results. Pathologic staging was later compared with CT staging. Pathologic T-stage was T1 in 70 cases(38.9%), T2 in 33(18.3%), T3 in 73(40.6%), and T4 in 4(2.2%). Type-I or IIa elevated lesions accouted for 10 of 70 T1 cases(14.3%) and flat or depressed lesions(type IIb, IIc, or III) for 60(85.7%). Pathologic N-stage was NO in 85 cases(47.2%), N1 in 42(23.3%), N2 in 31(17.2%), and N3 in 22(12,2%). The detection rate of early gastric cancer using two-phase spiral CT was 100.0%(10 of 10 cases) among elevated lesions and 78.3%(47 of 60 cases) among flat or depressed lesions. With regard to T-stage, there was good correlation between CT image and pathology in 86 of 180 cases(47.8%). Overstaging occurred in 23.3%(42 of 180 cases) and understaging in 28.9%(52 of 180 cases). With regard to N-stage, good correlation between CT image and pathology was noted in 94 of 180 cases(52.2%). The rate of understaging(31.7%, 57 of 180 cases) was higher than that of overstaging(16.1%, 29 of 180 cases)(p<0.001). The detection rate of early gastric cancer using two-phase spiral CT was 81.4%, and there was no significant difference in detectability between elevated and depressed lesions. Two-phase spiral CT for determing the T-and N-stage of gastric cancer was not effective;it was accurate in abont 50% of cases understaging tended to occur.=20

  17. The findings and the role of axial CT imaging and 3D imaging of gastric lesion by spiral CT

    International Nuclear Information System (INIS)

    Lee, Dong Ho; Ko, Young Tae

    1996-01-01

    The purpose of this study is to assess the efficacy of axial CT imaging and 3D imaging by spiral CT in the detection and evaluation of gastric lesion. Seventy-seven patients with pathologically-proven gastric lesions underwent axial CT and 3D imaging by spiral CT. There were 49 cases of advanced gastric carcinoma(AGC), 21 of early gastric carcinoma (EGC), three of benign ulcers, three of leiomyomas, and one case of lymphoma. Spiral CT was performed with 3-mm collimation, 4.5mm/sec table feed, and 1-1.5-mm reconstruction interval after the ingestion of gas. 3D imaging was obtained using the SSD technique, and on analysis a grade was given(excellent, good, poor). Axial CT scan was performed with 5-mm collimation, 7mm/sec table feed, and 5-mm reconstruction interval after the ingestion of water. Among 49 cases of AGC, excellent 3D images were obtained in seven patients (14.3%), good 3D images in 30(61.2%), and poor 3D images in 12(24.5%). Among the 12 patients with poor images, the cancers were located at the pyloric antrum in eight cases, were AGC Borrmann type 4 in three cases, and EGC-mimicking lesion in one case. Using axial CT scan alone, Borrmann's classification based tumor morphology were accurately identified in 67.3% of cases, but using 3D imaging, the corresponding figure was 85.7%. In 33 cases receiving surgery, good correlation between axial CT scan and pathology occurred in 72.7% of T class, and 69.7% of N class. Among 21 cases of EGC, excellent 3D images were obtained in three patients (14.3%), good 3D images in 14 (66.7%), and poor 3D images in two (9.5%). The other two cases of EGC were not detected. By axial CT scan, no tumor was detected in four cases, and there were two doubtful cases. 3D images of three benign ulcers were excellent in one case and good in two. 3D images of three leiomyomas and one lymphoma were excellent. Combined axial CT imaging and 3D imaging by spiral CT has the potential to accurately diagnose gastric lesions other than AGC

  18. Diagnosis of tracheal instability: inspiratory and expiratory spiral CT and cine CT

    International Nuclear Information System (INIS)

    Heussel, C.P.; Thelen, M.; Kauczor, H.U.; Hafner, B.; Lill, J.

    2000-01-01

    Purpose: In tracheo- and bronchomalacia, localization and determination of collapse is necessary for planning a surgical procedure. We compared inspiratory and spiral CT, cine CT, and bronchoscopy and evaluated the relevance of each method. Methods: Seventeen patients with suspected or verified tracheal stonosis or collapse underwent paired inspiratory and exspiratory spiral CT and cine CT during continuous respiration (temporal increment 100 ms). The tracheal cross-sectional area was calculated and compared. Results: In addition to bronchoscopy, further information concerning localization, extent, collapse, stability of the tracheal wall, distal portions of the stenosis, and extraluminal compressions was obtained. A significantly higher degree of tracheal collapse was seen using cine CT compared to paired spiral CT (p [de

  19. Floating venous thrombi: diagnosis with spiral-CT-venography; Diagnose flottierender venoeser Thromben mittels Phlebo-Spiral-CT

    Energy Technology Data Exchange (ETDEWEB)

    Gartenschlaeger, M. [Mainz Univ. (Germany). Klinik fuer Radiologie; Klose, K.J. [Univ. Marburg, Medizinisches Zentrum fuer Innere Medizin, Abt. Poliklinik (Germany); Schmidt, J.A. [Univ. Marburg, Medizinisches Zentrum fuer Radiologie, Abt. fuer Strahlendiagnostik (Germany)

    1996-05-01

    Local application of contrast agent into an ipsilateral dorsal foot vein and spiral CT were used to examine 16 consecutive cases with deep venous thrombosis proven at conventional venography; in addition, colour Doppler flow imaging was performed. At conventional venography, 8/16 thrombi appeared to be floating and the remaining 8/16 were adherent to the vessel wall. Spiral-CT showed 15/16 thrombi to be adherent to the vessel wall; the floating thrombus correlated with findings in conventional venography. At colour Doppler flow imaging 3/16 thrombi were considered floating, one of them was discordant to conventional venography. The comparison of conventional venography to spiral-CT demonstrates complete agreement for adherence to vessel wall seen in conventional venography (p=1,0) and significant discordance in cases with free-floating appearance in conventional venography. Adherence of thrombi to the wall of the vessel at conventional venography is in agreement with computed tomography. Conventional venography probably overestimates the prevalence of free floating thrombi. (orig./MG) [Deutsch] Mittels lokaler Kontrastmittelapplikation in eine ipsilaterale Fussrueckenvene und Spiral-CT wurden 16 konsekutive Faelle konventionell phlebographisch gesicherter Phlebothrombose untersucht, zusaetzlich wurde die farbkodierte Doppler-Ultraschalluntersuchung durchgefuehrt. In der konventionellen Phlebographie waren 8/16 Thromben flottierend, die uebrigen 8/16 wandadhaerent. In der Spiral-CT zeigten sich Wandadhaerenzen in 15/16 Faellen; der nachgewiesene flottierende Thrombus stimmte mit der konventionellen Phlebographie ueberein. Im farbkodierten Doppler-Ultraschall erschienen die Thromben in 3/16 Faellen flottierend, darunter ein von der konventionellen Phlebographie abweichender Befund. Der Vergleich von konventioneller und CT-Phlebographie ergab eine komplette Uebereinstimmung fuer konventionell phlebographisch nachgewiesene Wandadhaerenz und eine signifikante Abweichung

  20. Spiral CT colonography in inflammatory bowel disease

    International Nuclear Information System (INIS)

    Tarjan, Zsolt; Zagoni, Tamas; Gyoerke, Tamas; Mester, Adam; Karlinger, Kinga; Mako, Erno K.

    2000-01-01

    Objective: Most of the studies on virtual colonoscopy are dealing with the role of detecting colorectal polyps or neoplasms. We have undertaken this study to evaluate the value of CT colonography in patients with colonic Crohn's disease. Methods and material: Five patients (three males, two females, 23-51 years, mean age 42 years) with known (4) or suspected (1) Crohn's disease of the colon underwent fiberoptic colonoscopy and CT colonography in the same day or during a 1-week period. The images were evaluated with the so called zoomed axial slice movie technique and in some regions intra- and extraluminal surface shaded and volume rendered images were generated on a separate workstation. The results were compared to those of a colonoscopy. Results: The final diagnosis was Crohn's disease in four patients and colitis ulcerosa in one. Total examination was possible by colonoscopy in two cases, and with CT colonography in all five cases. The wall of those segments severely affected by the disease were depicted by the axial CT scans to be thickened. The thick walled, segments with narrow lumen seen on CT colonography corresponded to the regions where colonoscopy was failed to pass. Air filled sinus tracts, thickening of the wall of the terminal ileum, loss of haustration pseudopolyps and deep ulcers were seen in CT colonography. Three dimensional (3D) endoluminal views demonstrated pseudopolyps similar to endoscopic images None of the colonoscopically reported shallow ulcerations or aphtoid ulcerations or granular mucosal surface were observed on 2- or 3D CT colonographic images. Conclusion: CT colonography by depicting colonic wall thickening seems to be a useful tool in the diagnosis of Crohn's colitis, which could be a single examination depicting the intraluminal, and transmural extent of the disease

  1. Clinical application of 3D spiral CT of the auditory ossicular chain and labyrinth: Preliminary report

    International Nuclear Information System (INIS)

    Huang Yong; Wang Yisheng

    1998-01-01

    Purpose: To assess the clinical application and limitation of 3D spiral CT of the auditory ossicular chain and labyrinth. Methods: 3D reconstruction of the auditory ossicular chain and labyrinth, including multiplanar reformation (MPR), minimum or maximum intensity projection (MinIP or MaxIP) and shaded surface display (SSD), were performed with 1 mm slice thickness, 5 cm field of view and 0.1 mm reconstruction interval spiral CT in 14 normal subjects, 15 patients with middle ear diseases. Results: With use of 3D reconstruction images in 14 normal subjects, 13 cases of ossicular chain showed that the long process of the incus was parallel to the manubrium and projected inferomedian toward the cochlear promontory, the incus-stapedial joint was like a 'L-shape' structure, and in 8 cases of labyrinth reconstruction, the cochlea and the three semicircular canals were demonstrated. 9 cholesteatomas of 13 chronic otitis media demonstrated destruction of ossicular chain of varying degrees. In 2 cases with congenital abnormality, ossicle dysplasia was seen. Conclusion: 3D CT is a useful technique for evaluating anatomic malformations and diseases of middle and inner ear, but there are still few pitfalls

  2. Spiral CT pneumocolon: applications, status and limitations

    International Nuclear Information System (INIS)

    Harvey, C.J.; Renfrew, I.; Taylor, S.; Gillams, A.R.; Lees, W.R.

    2001-01-01

    CT pneumocolon is a promising new technique in the diagnosis and management of colon pathology. CT pneumocolon can detect (sensitivity >95%) and stage (accuracy 79%) colorectal cancer and is very accurate in the differentiation of malignant from benign colonic pathologies. It has excellent detection rates for polyps >10 mm in diameter. Several studies using 3D virtual colonoscopy have already proven its high sensitivity and specificity in polyp detection making this technique robust as a screening tool. The combined results for virtual colonoscopy, from all centres, show a sensitivity of >85% in the detection of polyps 10 mm or greater in size, 70-80% for 5-9 mm polyps and an overall specificity of 90%. CT pneumocolon is a safe, non-invasive and cost-effective method for detecting colonic carcinomas and adenomas and correctly identifying which patients need further colonoscopy. The technique is quick, well tolerated and non-operator dependent. It can also image the proximal colon when distal stenoses prevent endoscopic and barium examination. CT pneumocolon is able to identify the features and complications of inflammatory bowel disease. Further research is warranted to fully assess its impact in terms of a screening tool, acceptability, availability and cost benefit. (orig.)

  3. Comparative analysis between spiral CT and pathology of pulmonary nodules

    International Nuclear Information System (INIS)

    Wang Kaifu; Zhang Zhanqing

    2007-01-01

    Objective: To explore the value of spiral CT in the diagnosis of atypical pulmonary nodules. Methods: CT, clinic and histopathologic data of 72 patients with atypical pulmonary nodules confirmed by surgical resection in 41 cases and/or biopsy in 31 cases were retrospectively analyzed. Results: CT scans demonstrated slight lobulation in 34 cases, irregular margin in 50 cases, long speculate in 10 cases, air-bronchogram in 2 case, vacuole in 2 case. 38 pulmonary cancer, 22 pulmonary tuberculosis and 12 pulmonary inflammatory pseudotumors were diagnosed with spiral CT. However, 30 pulmonary cancer, 30 pulmonary tuberculosis and 12 pulmonary inflammatory pseudotumors were confirmed by histopathology. The overall accurate diagnostic rate of pulmonary cancer was 66.7% (20/30), pulmonary tuberculosis was 60%(18/30), pulmonary inflammatory pseudotumors was 16.7%(2/12). 40 cases were diagnosed correctly and 32 cases were misdiagnosed with CT in 72 cases of atypical pulmonary nodules. The misdiagnostic rate of CT was 44.4%. 10 cases of lung cancer were misdiagnosed, including 4 cases of tuberculosis (long speculate or irregular margin) and 6 cases of inflammatory pseudotumors (irregular margin or long speculate or air-bronchogram). 12 cases of tuberculosis were misdiagnosed, including 8 cases lung cancer (slight lobulation) and 4 cases of inflammatory pseudotumors (slight lobulation). 10 cases inflammatory pseudotumor were misdiagnosed as lung cancer (slight lobulation). Conclusion: Spiral CT was very useful in the localization and morphological describing, but difficult in qualitative diagnosing of atypical pulmonary nodules, exactly diagnosis was relied on surgery and biopsy. (authors)

  4. Fast reconstruction of industry CT image based on Wintel and P4 structure

    CERN Document Server

    Su Jian Ping; Zhang Li; Zhao Zi Ran; Gao Wen Huan; Kang Ke Jun

    2002-01-01

    Largescale I-CT is used to inspect large workpiece with high spiral resolution and its reconstructed image is very large. So it often relies on special workstation. Now with the development of P4 CPU and Windows2000, it is possible to reconstruct, deal and display I-CT image on Wintel structure. The authors discuss the possibility and future of this scheme. This is important for the improvement of economical value of I-CT

  5. The diagnostic value of multi-slice spiral CT virtual bronchoscopy in tracheal and bronchial disease

    International Nuclear Information System (INIS)

    Han Ying; Ma Daqing

    2006-01-01

    Objective: To assess the diagnostic value of multi-slice spiral CT virtual bronchoscopy (CTVB) in tracheal and bronchial disease. Methods: Forty-two patients including central lung cancer (n=35), endobronchial tuberculosis (n=3), intrabronchial benign tumor (n=3), and intrabronchial foreign body (n=1) were examined by using multi-slice spiral CT examinations. All the final diagnosis were proved by pathology except 1 patient with endoluminal foreign body was proved by clinic. All patients were scanned on GE Lightspeed 99 scanner, using 10 mm collimation, pitch of 1.35, and reconstructed at 1 mm intervals and 1.25 mm thickness. The chest images of transverse CT and virtual bronchoscopy were viewed by two separate radiologists who were familiar with the tracheal and bronchial anatomy. Results: Among the 42 patients, the tumor of trachea and bronchial lumen appeared as masses in 22 of 35 patients with central lung cancer and bronchial stenosis was found in 13 of 35 patients with central lung cancer, and bronchial wall thickening was revealed on transverse CT in all 35 cases. 3 patients of endobronchial tuberculosis showed bronchial lumen narrowing on CTVB, the bronchial wall thickening was revealed on transverse CT, and the length of the wall thickening was long. 3 patients with intrabronchial benign tumor showed nodules in trachea and bronchial lumen on CTVB, and without wall thickening on transverse CT. CTVB could detect the occlusion of bronchial lumen in 1 patient with intrabronchial foreign body and CTVB was able to visualize the areas beyond stenosis, and the bronchial wall was without thickening on transverse CT. Conclusion: Multi- slice spiral CTVB could reflect the morphology of tracheal and bronchial disease. Combined with transverse CT, it could provide diagnostic reference value for bronchial disease. (authors)

  6. Multidetector spiral CT arthrography of the shoulder

    Energy Technology Data Exchange (ETDEWEB)

    Lecouvet, Frederic E. [Departments of Radiology and Orthopaedic Surgery, Cliniques Universitaires Saint-Luc, Universite Catholique de Louvain, Hippocrate Avenue 10/2942, 1200 Brussels (Belgium)], E-mail: frederic.lecouvet@uclouvain.be; Simoni, Paolo; Koutaissoff, Sophie; Vande Berg, Bruno C.; Malghem, Jacques; Dubuc, Jean-Emile [Departments of Radiology and Orthopaedic Surgery, Cliniques Universitaires Saint-Luc, Universite Catholique de Louvain, Hippocrate Avenue 10/2942, 1200 Brussels (Belgium)

    2008-10-15

    Although MR imaging and MR arthrography are the first choice modalities for shoulder imaging, CT arthrography (CTA) may be used successfully to address many clinical questions. The advent of submillimeter multiple detector CT technology and subsequent excellent three-plane resolution has considerably increased the quality of CTA examinations and has propelled this technique to the forefront in a growing number of indications. The combined use of iodinated contrast material for fluoroscopic confirmation of the articular position of the needle before injection of gadolinium chelates for MR arthrography offers the unique opportunity to compare CTA and MRA findings in carefully selected cases. This paper illustrates capabilities and limits of CTA for the study of rotator cuff tears, shoulder instability, cartilage lesions, anatomical variants and abnormalities of the glenoid labrum, with correlations to MR arthrography and surgical findings.

  7. Multidetector spiral CT arthrography of the shoulder

    International Nuclear Information System (INIS)

    Lecouvet, Frederic E.; Simoni, Paolo; Koutaissoff, Sophie; Vande Berg, Bruno C.; Malghem, Jacques; Dubuc, Jean-Emile

    2008-01-01

    Although MR imaging and MR arthrography are the first choice modalities for shoulder imaging, CT arthrography (CTA) may be used successfully to address many clinical questions. The advent of submillimeter multiple detector CT technology and subsequent excellent three-plane resolution has considerably increased the quality of CTA examinations and has propelled this technique to the forefront in a growing number of indications. The combined use of iodinated contrast material for fluoroscopic confirmation of the articular position of the needle before injection of gadolinium chelates for MR arthrography offers the unique opportunity to compare CTA and MRA findings in carefully selected cases. This paper illustrates capabilities and limits of CTA for the study of rotator cuff tears, shoulder instability, cartilage lesions, anatomical variants and abnormalities of the glenoid labrum, with correlations to MR arthrography and surgical findings

  8. Design of wireless data transmission system for spiral CT

    International Nuclear Information System (INIS)

    Wang Jue; Wang Fuquan; Liu Huaili

    2010-01-01

    A new wireless data transmission scheme based on UWB was proposed after studying the structure and character of spiral CT transmission system, the system was designed and validated. Using UWB device as wireless module to realize wireless data transmission. Using FPGA as main controller to meet the requirement of timing control for system module. Using two pieces of SDRAM in pingpang operation to realize large capacity storage mechanism. Using USB 2.0 interface to realize high-speed connection with UWB module. The results show that the transmission speed of the system arrival at 16.87 M bit ps within 3 meters, and the precision is 100%, it can be used for line-array spiral CT. (authors)

  9. Exact cone beam CT with a spiral scan

    International Nuclear Information System (INIS)

    Tam, K.C.; Samarasekera, S.; Sauer, F.

    1998-01-01

    A method is developed which makes it possible to scan and reconstruct an object with cone beam x-rays in a spiral scan path with area detectors much shorter than the length of the object. The method is mathematically exact. If only a region of interest of the object is to be imaged, a top circle scan at the top level of the region of interest and a bottom circle scan at the bottom level of the region of interest are added. The height of the detector is required to cover only the distance between adjacent turns in the spiral projected at the detector. To reconstruct the object, the Radon transform for each plane intersecting the object is computed from the totality of the cone beam data. This is achieved by suitably combining the cone beam data taken at different source positions on the scan path; the angular range of the cone beam data required at each source position can be determined easily with a mask which is the spiral scan path projected on the detector from the current source position. The spiral scan algorithm has been successfully validated with simulated cone beam data. (author)

  10. Floating venous thrombi: diagnosis with spiral-CT-venography

    International Nuclear Information System (INIS)

    Gartenschlaeger, M.; Schmidt, J.A.

    1996-01-01

    Local application of contrast agent into an ipsilateral dorsal foot vein and spiral CT were used to examine 16 consecutive cases with deep venous thrombosis proven at conventional venography; in addition, colour Doppler flow imaging was performed. At conventional venography, 8/16 thrombi appeared to be floating and the remaining 8/16 were adherent to the vessel wall. Spiral-CT showed 15/16 thrombi to be adherent to the vessel wall; the floating thrombus correlated with findings in conventional venography. At colour Doppler flow imaging 3/16 thrombi were considered floating, one of them was discordant to conventional venography. The comparison of conventional venography to spiral-CT demonstrates complete agreement for adherence to vessel wall seen in conventional venography (p=1,0) and significant discordance in cases with free-floating appearance in conventional venography. Adherence of thrombi to the wall of the vessel at conventional venography is in agreement with computed tomography. Conventional venography probably overestimates the prevalence of free floating thrombi. (orig./MG) [de

  11. Demonstration of pulmonary embolism with gadolinium-enhanced spiral CT

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    Coche, E.E.; Hammer, F.D.; Goffette, P.P. [Dept. of Radiology, St. Luc University Hospital, Brussels (Belgium)

    2001-11-01

    The authors report a case of successful detection of pulmonary embolism using gadolinium-enhanced spiral CT (Gadodiamide, 0.4 mmol/kg, 2 ml/s, delay 18 s) in a 77-year-old woman, with previous allergy to iodinated contrast medium, and renal failure, who presented with pulmonary arterial hypertension. Doppler ultrasound of the lower limbs was first performed and revealed a deep venous thrombosis of the right lower limb. To establish if venous thrombosis was the cause of pulmonary hypertension and to confirm that pulmonary endarterectomy was not indicated in this situation, several imaging modalities were performed. Lung scintigraphy and MRI were non-diagnostic. Gadolinium-enhanced spiral CT demonstrated a large thrombus located proximally and in a segmental artery of the right lower lobe. This case illustrates the potential usefulness of gadolinium as alternative contrast agent with spiral CT to diagnose pulmonary embolism and elucidate the cause of pulmonary arterial hypertension in a patient with some contraindications for iodinated contrast medium injection. (orig.)

  12. Demonstration of pulmonary embolism with gadolinium-enhanced spiral CT

    International Nuclear Information System (INIS)

    Coche, E.E.; Hammer, F.D.; Goffette, P.P.

    2001-01-01

    The authors report a case of successful detection of pulmonary embolism using gadolinium-enhanced spiral CT (Gadodiamide, 0.4 mmol/kg, 2 ml/s, delay 18 s) in a 77-year-old woman, with previous allergy to iodinated contrast medium, and renal failure, who presented with pulmonary arterial hypertension. Doppler ultrasound of the lower limbs was first performed and revealed a deep venous thrombosis of the right lower limb. To establish if venous thrombosis was the cause of pulmonary hypertension and to confirm that pulmonary endarterectomy was not indicated in this situation, several imaging modalities were performed. Lung scintigraphy and MRI were non-diagnostic. Gadolinium-enhanced spiral CT demonstrated a large thrombus located proximally and in a segmental artery of the right lower lobe. This case illustrates the potential usefulness of gadolinium as alternative contrast agent with spiral CT to diagnose pulmonary embolism and elucidate the cause of pulmonary arterial hypertension in a patient with some contraindications for iodinated contrast medium injection. (orig.)

  13. Abdominal wall hernias: imaging with spiral CT

    International Nuclear Information System (INIS)

    Stabile Ianora, A.A.; Midiri, M.; Vinci, R.; Rotondo, A.; Angelelli, G.

    2000-01-01

    Computed tomography is an accurate method of identifying the various types of abdominal wall hernias, especially if they are clinically occult, and of distinguishing them from other diseases such as hematomas, abscesses and neoplasia. In this study we examined the CT images of 94 patients affected by abdominal wall hernias observed over a period of 6 years. Computed tomography clearly demonstrates the anatomical site of the hernial sac, the content and any occlusive bowel complications due to incarceration or strangulation. Clinical diagnosis of external hernias is particularly difficult in obese patients or in those with laparotic scars. In these cases abdominal imaging is essential for a correct preoperative diagnosis and to determine the most effective treatment. (orig.)

  14. Three-dimensional spiral CT of craniofacial malformations in children

    International Nuclear Information System (INIS)

    Binaghi, S.; Gudinchet, F.

    2000-01-01

    Objective. To assess the value of three-dimensional CT (3D CT) in the diagnosis and management of suspected paediatric craniofacial malformations. Materials and methods. Twenty-eight children (12 girls, 16 boys) with a mean age of 4 years, suffering from craniofacial or cervical malformations, underwent craniofacial spiral CT. 3D reformatting was performed using an independent workstation. Results. 3D CT allowed the preoperative evaluation of 16 patients with craniosynostosis and the post-surgical management of 2 patients. 3D CT clearly depicted malformations of the skull base involving the petrous bone in seven patients (four cases of Goldenhar-Gorlin syndrome, one case of Treacher-Collins syndrome and two cases of Crouzon's disease). Four patients with craniofacial clefts were also evaluated. Radiological findings were confirmed by the clinical and intraoperative findings in all patients that underwent surgical treatment. Movement artefacts and ''Lego effect'' related to abrupt change of cranial vault border were encountered and are discussed. Conclusions. 3D CT of the skull can safely and reliably identify paediatric craniofacial malformations involving bone, and it should be used as morphological mapping to help the surgeon in planning surgical treatment. (orig.)

  15. Skeletal and total body volumes of human fetuses: assessment of reference data by spiral CT

    International Nuclear Information System (INIS)

    Braillon, Pierre M.; Buenerd, Annie; Bouvier, Raymonde; Lapillonne, Alexandre

    2002-01-01

    Objective: To define reference data for skeletal and total body volumes of normal human fetuses. Materials and methods: Spiral CT was used to assess the skeletal and total body volumes of 31 normal human stillborn infants with gestational age (GA) and body weight (BW) ranging from 14 to 41.5 weeks and 22 to 3,760 g, respectively. CT scans (slice thickness 2.7 mm, pitch 0.7) were performed within the first 24 h after delivery. Precise bone and soft-tissue windows were defined from analysis of the density along the diaphysis of the fetal long bones and from the measurement of a phantom that mimics soft tissues. Lengths and volumes were obtained from 3D reconstructions. The femur lengths measured from CT images (FLct) were compared with those provided by US studies (FLus). Results: Significant correlations (r>0.9) were found between BW, measured volumes of the entire skeleton or head, long-bone lengths, biparietal diameter and GA. Strong linear correlations (r>0.98) were observed between FLct and FLus. Conclusions: Skeletal and total body volume values obtained using spiral CT were significantly correlated with fetal biometric measurements. These data could complement those obtained in obstetric investigations with US. (orig.)

  16. Abdominal spiral CT in children: which radiation exposure is required?

    Energy Technology Data Exchange (ETDEWEB)

    Wormanns, D.; Diederich, S.; Lenzen, H.; Ludwig, K.; Papke, Karsten; Hagedorn, Claudia; Heindel, Walter [Muenster Univ. (Germany). Inst. fuer Klinische Radiologie; Lange, P.; Link, T.M. [Muenster Univ. (Germany). Inst. fuer Klinische Radiologie; Dept. of Radiology, Technical Univ. Muenchen (Germany)

    2001-11-01

    We decided to test to what extent dose reduction is possible in abdominal spiral computed tomography (CT) in young children without loss of anatomic diagnostic information. A retrospective study was performed of 30 abdominal CT examinations of children aged 3 months to 7 years. These were divided into two groups: group A with reduced radiation exposure (tube current 50 mA, CT dose index CTDI{sub FDA} {<=}0.83 mGy) and group B with standard radiation exposure (tube current {>=}100 mA, CTDI{sub FDA} {>=}1.66 mGy). Image quality was assessed using a four-part scale ('excellent', 'good', 'sufficient', 'poor') on visual image impression and visibility of 32 anatomical details. Five experienced radiologists read the CT scans independently who were blinded to the examination parameters. Differences in ranked data were evaluated with Wilcoxon's rank sum test. No difference between groups A and B was observed in visual image impression. Detail visibility was significantly lower in group A, but the differences were limited to right upper quadrant structures (portal vein, common bile duct, pancreatic head, adrenals) and to arterial branches. Significant differences in visibility rated as 'poor' were only found for the hepatic, splenic and renal arteries; all other structures showed no difference between groups A and B. A protocol with reduced radiation exposure (50 mA, CTDI{sub FDA} {<=}0.83 mGy) allowed the demonstration of most anatomic structures in abdominal spiral CT in young children. For the precise demonstration of small details (e.g. structures of the right upper quadrant), a protocol with standard radiation exposure ({>=}100 mAs) was superior. (orig.)

  17. Evaluation of image quality and dose in renal colic: comparison of different spiral-CT protocols

    International Nuclear Information System (INIS)

    Rimondini, A.; Mucelli, R.P.; Dalla Palma, L.; De Denaro, M.; Bregant, P.

    2001-01-01

    The aim of this study was to test different technical spiral-CT parameters to obtain optimal image quality with reduced X-ray dose. Images were acquired with a spiral-CT system Philips Tomoscan AVE1, using 250 mA, 120 kV, and 1-s rotational time. Three protocols were tested: protocol A with 5-mm thickness, pitch 1.6, slice reconstruction every 2.5 mm; protocol B with 3-mm thickness, pitch 1.6, slice reconstruction every 1.5 mm; and protocol C with 3-mm thickness, pitch 2, slice reconstruction every 1.5 mm. Two phantoms were employed to evaluate the image quality. Axial images were acquired, then sagittal and coronal images were reconstructed. Finally, the absorbed X-ray dose for each protocol was measured. Regarding image quality, 5-mm-thick images (protocol A) showed greater spatial resolution and lower noise compared with 3-mm-thick images (protocols B and C) on the axial plane; 3-mm reconstructed sagittal and coronal images (protocols B and C) showed an improved image quality compared with 5-mm reformatted images (protocol A). Concerning X-ray dose, the mean dose was: protocol A 19.6±0.8 mGy; protocol B 14.4±0.6 mGy; protocol C 12.5±1.0 mGy. Our study supports the use of thin slices (3 mm) combined with pitch of 1.6 or 2 in renal colic for X-ray dose reduction to the patient and good image quality. (orig.)

  18. Pulmonary embolism: spiral CT evaluation; Embolie pulmonaire: apport de la tomodensitometrie helicoidale

    Energy Technology Data Exchange (ETDEWEB)

    Senac, J.P.; Vernhet, H.; Bousquet, C.; Giron, J.; Pieuchot, P.; Durand, G.; Benezet, O.; Aubas, P. [Centre Hospitalier Universitaire, 34 - Montpellier (France)

    1995-06-01

    Purpose: Spiral computed tomography was compared retrospectively with digital substraction pulmonary angiography (PA) in 45 patients suspected of having acute or chronic pulmonary embolism. Materials and method : 45 patients in whom the presence of acute or chronic pulmonary embolism was suspected underwent examination by spiral CT and PA. Diagnosis of pulmonary embolism was based on the direct visualization of intraluminal clots. The study of the agreement between the two methods was based on the Kappa test. In 35 cases, pulmonary emboli were proved. Acute pulmonary emboli were present in 28 cases and chronic in 7 cases. Results: Spiral computed tomography represents an excellent way to detect acute pulmonary embolism. In the chronic form, spiral CT is better than PA to detect intraluminal clots. However, Spiral CT can fail to detect small emboli in the peripheral arterial bed. In the 10 patients without pulmonary embolism, the spiral CT proved diagnosis pulmonary oedema (n=3), lymphangi-carcinoma (n=4), pleural effusion (n=3). Conclusion: This study suggest that the spiral CT examination is accurate for diagnosis of pulmonary embolism specifically in case of suspected important embolism. The advantages of spiral CT are multiple (non invasive, wide diagnosis spectrum). However, may be a limitation to is use is insufficient distal thrombi detection. This eventuality (5 to 10% in the Pioped study) justify the practice of pulmonary angiography. Spiral CT improvements should reduce this insufficiency in the next future. (Authors). 16 refs., 4 figs., 3 tabs.

  19. A backprojection-filtration algorithm for nonstandard spiral cone-beam CT with an n-PI-window

    International Nuclear Information System (INIS)

    Yu Hengyong; Ye Yangbo; Zhao Shiying; Wang Ge

    2005-01-01

    For applications in bolus-chasing computed tomography (CT) angiography and electron-beam micro-CT, the backprojection-filtration (BPF) formula developed by Zou and Pan was recently generalized by Ye et al to reconstruct images from cone-beam data collected along a rather flexible scanning locus, including a nonstandard spiral. A major implication of the generalized BPF formula is that it can be applied for n-PI-window-based reconstruction in the nonstandard spiral scanning case. In this paper, we design an n-PI-window-based BPF algorithm, and report the numerical simulation results with the 3D Shepp-Logan phantom and Defrise disk phantom. The proposed BPF algorithm consists of three steps: cone-beam data differentiation, weighted backprojection and inverse Hilbert filtration. Our simulated results demonstrate the feasibility and merits of the proposed algorithm

  20. Multi-slice spiral CT diagnosis of carotid body tumor

    International Nuclear Information System (INIS)

    Li Peiling; Leng Renli; Li Shu; Xie Xiuli; Xu Ke

    2006-01-01

    Objective: to explore the Multi-slice spiral CT (MSCT) findings of carotid body tumor (CBT). Methods: Twelve cases of CBT proved by surgery were collected in this study and all patients accepted contrast-enhanced MSCT examination. Two-dimensional and three-dimensional post-processing were performed at diagnostic workstation using Aquilion 1.42. The CT features of CBT were analyzed. Results Each of 12 patients had one lesion. All lesions demonstrated well-marginated masses of homogeneous soft- tissue density with CT value within 29-48 HU on pre-enhanced images. All lesions were markedly enhanced with CT value over 200 HU on arterial-phase images, and the density of lesions decreased rapidly on delay- phase images. Twelve lesions were all located at the level of carotid artery bifurcation, 3 of them enveloping common carotid artery and internal/external carotid artery, and other 9 of them riding right on the carotid bifurcation. Internal carotid artery usually were shifted toward posterior-lateral, and external carotid artery toward anterior or anterior-medial. Conclusion: Contrast-enhanced MSCT examination not only can make a qualitative diagnosis of CBT, but determine its accurate location. It plays an importantly instructional role in clinical diagnosis and treatment. (authors)

  1. Clinical application of low-dose spiral CT for orthodontics

    International Nuclear Information System (INIS)

    Xie Na; Gan Yungen; Shu Huang; Lin FeiFei; Li Zhiyong; Sun Jie

    2009-01-01

    Objective: To determine the effect of reducing the value of mA or kV on the image quality and the radiation dose of the patients undergoing low-dose spiral CT for orthodontics. Methods: Thirty patients were divided into three groups, each group has 10 patients. They were group 1 (80 kV and 200 mA), group 2 (120 kV and 80 mA), group 3 (120 kV and 200 mA) The volume CT dose index (CTDI) was recorded and the average dose-length produce (DLP) was calculated in three groups,respectively. Image quality of three groups were compared and scored by two radiologists, and the results were statistically analysed. Results: The CTDI and DLP of 80 kV group (group 2) were 8.7 mGy and (36.80 ± 3.60) mGy · cm, respectively, those of 80 mA group (group 3) were 19.6 mGy and (82.14 ± 7.18) mGy · cm, respectively, and those of conventional-dose group (group 1) were 19.6 mGy and (82.14 ± 7.18) mGy · cm, respectively. There was no significant difference among three groups in diagnostic image quality. Conclusions: Low-dose spiral CT for orthodontics, especially the low-kV scan, may decrease the radiation exposure and guarantee the image quality. (authors)

  2. Percutaneous CT-guided lung biopsy: sequential versus spiral scanning. A randomized prospective study

    International Nuclear Information System (INIS)

    Ghaye, B.; Dondelinger, R.F.; Dewe, W.

    1999-01-01

    The aim of this study was to evaluate in a prospective and randomized study spiral versus sequential scanning in the guidance of percutaneous lung biopsy. Fifty thoracic lesions occurring in 48 patients were biopsied by a senior and a junior operator. Six different time segments of the procedure were measured. Scanning mode versus length of procedure, pathological results, irradiation and complications were evaluated. Total duration of the procedure and of the first sampling was significantly longer with spiral CT for the senior operator (p < 0.004). No significant time difference was observed for the junior operator. Diameter of the lesion, depth of location, position of the patient and needle entry site did not influence the results. The sensitivity was 90.9, specificity 100, positive predictive value 100 and negative predictive value 60 % for spiral CT, and 94.7, 100, 100 and 85.7 % for sequential CT, respectively. Eleven pneumothoraces and ten perinodular hemorrhages were seen with spiral CT and six and ten, respectively, with sequential CT. The mean dose of irradiation was 4027 mAs for spiral CT and 2358 mAs for conventional CT. Spiral CT does neither reduce procedure time nor the rate of complications. Pathological results do not differ compared with sequential CT, and total dose of irradiation is higher with spiral scanning. (orig.)

  3. Multi-slice spiral CT detects spread of small laryngeal tumors

    International Nuclear Information System (INIS)

    Bruening, R.; Schoepf, U.; Becker, C.; Reiser, M.; Hong, C.; Sturm, C.; Wollenberg, B.

    1999-01-01

    The purpose of the study was to preoperatively investigate small laryngeal carcinomas using multi-slice spiral CT (MSCT) and subsequent multiplanar reconstructions (MPR) and to compare the results to the detailed spread found a surgery and histology. Nine patients with small (T1, T2) laryngeal cancer were investigated on a MSCT scanner (Siemens plus 4 Volume Zoom, Siemens). A 4x1 mm collimation, 120 kV, 200 mAs and a 0.5 seconds rotation time were used, allowing a coverage of the entire larynx in approximately 10 seconds within a single breathhold. Multiplanar reconstruction's (MPR) in sagittal and coronal plane were reconstructed in all patients and rated in consensus reading. In 8 of nine patients, the glottic spread was detected by MSCT, in one case of a supraglottic tumor a glottic invasion was excluded. The infiltration of the anterior commissure, the infiltration into the subglottic space and the extension into the hypo-pharynx was correctly assessed in all patients. MSCT was not able to predict infiltration of the arythnoids in two patients. The use of multi-slice CT for the preoperative assessment of small laryngeal tumors shows great promise. The detection or exclusion of subtle spread of these tumors into the supra- or subglottic space and along the glottic level was possible with high accuracy. As the examination time is short, artifacts are rare and multiplanar reconstructions gain in clinical importance. (orig.) [de

  4. Three phase dynamic CT with double spiral CT: utility of determination of stomach cancer stage

    International Nuclear Information System (INIS)

    Jung, Min Ha; Kim, Hong In; Kim, Tae Hyung; Lee, Ki Yeol; Cho, June Il; Park, Cheol Min; Cha, In Ho

    1997-01-01

    To evaluate the utility of three phases of spiral CT in the diagnosis of stomach cancer. Between August 1994 and March 1995, thirty eight patients with stomach cancer, demonstrated on spiral CT, underwent surgery. Twenty-eight cases were advanced and ten were early. There were 27 men, and 11 women, and their average age was 52.8 years old (33-77). After ingestion of 600-700ml of water, 120-140ml of nonionic contrast material was injected intravenously. Spiral CT scanning was performed in 10mm slice thickness and of 10mm/sec table speed. Three phase image were obtained at 25sec (arterial phase), 60-65sec (venous phase) and 4min (equilibrium phase) after the start of bolus injection. On each phase, CT findings were compared with pathologic results, and tumor detectibility, depth of tumor invasion and lymph node metastasis was analysed. Thirty of the 38 carcinomas (79%) were detected on the arterial phase, 33 (81%) on the venous phase and 30 (79%) on the equilibrium phase. Depth of tumor invasion was measured accurately in 27 of 38 cases (71%) : T1-4/10 (40%), T2-8/11 (73%), T3-13/15 (87%), T4-2/2 (100%). We overstaged one case of T1 as T2 and two cases of T2 as T3, and understaged one case of T2 as T1 and two cases of T3 as T2. Among the 16 enlarged lymph nodes larger than 8mm, 13 cases were positive on pathologic examination and the sensitivity was 65%. With three-phase spiral CT scanning, we obtained 71% accuracy of depth of tumor invasion. The venous phase is most useful for tumor detection and for determining depth of tumor invasion and lymph node metastasis

  5. Hypoxic-ischemic encephalopathy in neonates and infants: an evaluation with spiral CT

    International Nuclear Information System (INIS)

    Zhu Linghua

    2006-01-01

    Objective: To evaluate spiral CT imaging in the diagnosis of hypoxic-ischemic encephalopathy (HIE) in the neonates and infants. Methods: 112 children with history of asphyxia in peri-natal period and evident clinical symptoms were evaluated with Spiral CT. CT findings were studied. Results: 46 minor cases, 57 moderate cases and 9 severe cases were found out of 112 patients. Intracranial hemorrhage was revealed in 38 cases. Mortality occurred in 1 case. Conclusion: Spiral CT is helpful for evaluating brain damage and predicting prognosis in neonates with HIE. (authors)

  6. The anal verge: localization with multi-slice spiral CT

    International Nuclear Information System (INIS)

    Wang Wei; Tang Guangjian

    2010-01-01

    Objective: To determine and evaluate the method of localization of anal verge by multislice spiral CT. To provide an imaging reference for operative guidance of low-rectal cancer. Methods Forty eight consecutive adult patients suspected of abnormalities other than rectal disease were evaluated with abdominal and pelvic CT scans since August, 2009. They were divided into two groups based on sex and age. There were 23 men and 25 women. The ages of young group were 28 to 50 years and the average age was 41 years. The ages of elderly group were 52 to 81 years and the average age was 64 years. A small cotton ball dipped with contrast media was put at the anal verge as a marker and CT scans were performed with 64-slice spiral CT scanner. The distances between the cotton balls and the lower margin of the pubis combination (La), the lower margin of the Sth sacral vertebra (Lb), the inferior aperture of minor pelvis (Lc) and the lower margin of the basement of external anal sphincter (Ld) were measured on the mid- sagittal images obtained by MPR. The averages, the standard deviations (s), the 95% and 80% confidence intervals of La, Lb, Lc and Ld were calculated. We took the intervals of ±1.96 s or ±1.28 s 0.05) between two different sex groups [male group, (10.0±1.2) mm], female group, (9.6±1.2) mm and between two age groups [young group, (9.6±1.2) mm, elderly group, (9.9±1.3) mm]. Conclusions: The lower margin of the basement of external anal sphincter was a useful anatomic landmark for localizing the anal verge, and could be definitely identified on the middle sagittal pelvic CT image. The distance between the structure and anal verge is constant enough and can be used in measuring distance from low rectal lesion to the anal verge. (authors)

  7. Induced pneumoperitoneum in spiral CT evaluation of gastric cancer

    International Nuclear Information System (INIS)

    Guo Hua; Gao Jianbo; Li Yintai; Yang Xuehua; Chen Xuejun; Guan Sheng

    2001-01-01

    Objective: To evaluate the diagnostic value and clinical significance of preoperative staging in gastric cancer with induced pneumoperitoneum in spiral CT (SCTPP). Methods: Both routine SCT and SCTPP were performed in 52 lean patients suffered from gastric cancers, and comparison was made between SCT findings and surgical and histopathologic findings. Results: The accuracy of routine SCT and SCTPP in determining the T-staging was 72% and 96%, respectively (x 2 = 8.0, P 2 = 0.006, P > 0.05). The sensitivity in determining M-staging was 61% and 100%, respectively (x 2 = 0.04, P 2 6.03, P < 0.05). Conclusion: The accuracy of SCTPP in determining preoperative staging of gastric cancer was significantly higher than that of routine SCT. SCTPP has important guiding significance for the selection of the treatment strategy in gastric cancer

  8. The influence factors in image quality of multi-slice spiral CT coronary angiography (MSCTA)

    International Nuclear Information System (INIS)

    Zeng Huiliang; Zhu Xinjin; Liang Jianhao; Zhong Yingze; Chen Xueguang; Ou Weiqian; Wen Haomao; Li Peiwen

    2007-01-01

    Objective: To evaluate the influence of heart rate on image quality of multi-slice spiral CT coronary angiography(MSCTA) and the optimization of image reconstruction windows. Methods: Retrospectively ECG-gated MSCT coronary angiography were performed in 67 cases. The cases were divided into four groups by heart rate, groupl with heart rate less than 60 beats per minute(bpm), group 2 with heart rate 61-70 bpm, group 3 with heart rate 71-80 bpm and group 4 with heart rate over 81 bpm. The impact of heart rate on image quality of MSCTA and the optimization of image reconstruction windows were evaluated. Results: 4 coronary (RCA,LM,LAD,LCX) segments were analyzed in each patients with regard to image quality. 86.7%(112/128) of the coronary segments were sufficient for analysis in patients with heart rate less than 60 bpm,62.5%(55/88) with 61-70 bpm,40%(8/20) with 71-80 bpm and 12.5%(2/16) with heart rate over 81 bpm, respectively. There were statistically significances between every coronary segments of group 1 and 2, group 3 and 4 (P<0.05). All coronary segments of group 1 were optimally visualized on the image reconstructed at 75% image reconstruction window of' cardiac cycle; 89.5% cases at 75% in group 2; for group 3.55% of coronary artery were best presented at 75% image reconstruction window, 45% of coronary artery at 45%; All coronary segments of group 4 were optimally visualized on the image reconstructed at 45% image reconstruction window. Conclusion: Image quality of MSCT coronary angiography is highly dependent on heart rate. Coronary artery is usually best shown at 75% image reconstruction window of cardiac cycle for those with heart rate less than 70 bpm. 30%-90% image reconstruction should be performed when heart rate is over 71 bpm. (authors)

  9. Whole-body CT. Spiral and multislice CT. 2. tot. rev. and enl. ed.

    International Nuclear Information System (INIS)

    Prokop, M.; Galanski, M.; Schaefer-Prokop, C.; Molen, A.J. van der

    2007-01-01

    Spiral and multidetector techniques have improved the diagnostic possibilities of CT, so that image analysis and interpretation have become increasingly complex. This book represents the current state of the art in CT imaging, including the most recent technical scanner developments. The second edition comprises the current state of knowledge in cT imaging. There are new chapters on image processing, application of contrasting agents and radiation dose. All organ-specific pathological findings are discussed in full. There are hints for optimum use and interpretation of CT, including CT angiography, CT colonography, CT-IVPL, and 3D imaging. There is an introduction to cardio-CT, from calcium scoring and CTA of the coronary arteries to judgement of cardiac morphology. There are detailed scan protocols with descriptions of how to go about parameter selection. Practical hints are given for better image quality and lower radiation exposure of patients, guidelines for patient preparation and complication management, and more than 1900 images in optimum RRR quality. (orig.)

  10. Diagnosis and staging of carcinoma localized in the antral part of the stomach with spiral CT

    International Nuclear Information System (INIS)

    Pomakov, P.; Grudeva, V.; Mlachkova, D.

    2009-01-01

    The aim of the study was to characterize CT images and stages of carcinomas localized in the antral part of the stomach obtained with spiral CT. Seven men aged from 54 years old to 81 years old inclusive, with subjective complaints and clinical suspicion of a neoplasm in the upper gastrointestinal tract were examine Examinations were performed following stomach wall re relaxation with Buscolysin.The stomach is distended by drinking 600 ml of water. Upper abdomen scans were performed with spiral CT/e General Electric with the following parameters: slice thickness 3-5 mm, spacing 3 mm, pitch 1,5, reconstruction index 3 mm. After the pre-contrast scans, 100 ml of non-ionic contrast media is administered intravenously with an injection rate of 30 ml/sec. Scan delay time - 30 seconds after start of injection. Exposition data-120 kV, 180 mAs. Carcinoma localized in the antral part of the stomach was demonstrated in 7 patients. The staging showed: I stage - one patient, II stage - 2, III stage - 1 and IV stage - three patients. According to the macro morphological characteristic: exophytic type - 4, endophytic tumor - 1, ulcerous tumor - 1 and early carcinoma - 1 patient. In our material only male patients were present. Early carcinoma was demonstrated in a male patient at an age of 80 years old. An enhancing nodular local thickness was visualized. Differential diagnosis between malignant and benign ulcer is necessary in certain cases. It is performed on the contrast scans, the malignant process enhances twice its density, When performing a purposive CT examination it is possible to diagnose neoplasms in the antral part of the stomach, from stage i to IV with different macro morphologic characteristic

  11. Whole-body CT. Spiral and multislice CT. 2. tot. rev. and enl. ed.; Ganzkoerper-Computertomographie. Spiral- und Multislice-CT

    Energy Technology Data Exchange (ETDEWEB)

    Prokop, M.; Galanski, M.; Schaefer-Prokop, C.; Molen, A.J. van der

    2007-07-01

    Spiral and multidetector techniques have improved the diagnostic possibilities of CT, so that image analysis and interpretation have become increasingly complex. This book represents the current state of the art in CT imaging, including the most recent technical scanner developments. The second edition comprises the current state of knowledge in cT imaging. There are new chapters on image processing, application of contrasting agents and radiation dose. All organ-specific pathological findings are discussed in full. There are hints for optimum use and interpretation of CT, including CT angiography, CT colonography, CT-IVPL, and 3D imaging. There is an introduction to cardio-CT, from calcium scoring and CTA of the coronary arteries to judgement of cardiac morphology. There are detailed scan protocols with descriptions of how to go about parameter selection. Practical hints are given for better image quality and lower radiation exposure of patients, guidelines for patient preparation and complication management, and more than 1900 images in optimum RRR quality. (orig.)

  12. Use of spiral CT angiography to judge central pulmonary vascular involvement from lung cancer

    International Nuclear Information System (INIS)

    Tan Qunyou; Zhao Shaohong; Wang Fangze; Cai Zulong

    2000-01-01

    Objective: To evaluate the accuracy of spiral CT angiography (SCTA) in judging central pulmonary vascular involvement from lung cancer located in the hilum and correlate the resultant images with pathologic and surgical findings. Methods: SCTA was done in 33 patients who were preoperatively diagnosed as having lung carcinoma located in the hilum. Contrast medium was injected at a rate of 3 ml/sec with a power injector. The delay time was from 20 to 25 seconds. The pitch was 1 with 3 mm-collimation. Images of central pulmonary arteries and veins were reconstructed with shaded surface display (SSD), maximum intensity projection (MIP), curved planar reformation (CPR), and multi-planar reformation (MPR). Then the relation between tumor and vessels was assessed prospectively on both 3 mm interval axial CT and SCTA images with comparison to subsequent pathologic or surgical findings. Results: (1) In showing the integrity of central pulmonary arteries and veins, images reconstructed by different ways of SCTA had different strong and weak points. (2) The grading standard in this study, with which the relation between vessels and tumor was judged, reflected the basic and common characters of central pulmonary vascular involvement by tumor located in the hilum. compared with axial CT images, SCTA was more accurate in judging the relation between central pulmonary vessels and tumor, and the correlation of SCTA imaging features with pathological patterns and surgical findings was better than that of axial CT images, P < 0.05 and P < 0.0001, respectively. Conclusion: It was feasible to show the relation between central pulmonary vessel and lung cancer located in the hilum with SCTA. And the accuracy of judging the vascular involvement with SCTA was higher than that with axial CT

  13. Preliminary application of 320-detector spiral CT with ECG editing for assessing coronary artery in-stent restenosis

    International Nuclear Information System (INIS)

    Li Zhiming; Tan Lilian; Li Shuxin; Fu Xi; He Weihong; Liu Ke; Huang Yong; Yu Lin

    2011-01-01

    Objective: To determine the value of 320-detector spiral CT with retrospective ECG gating and editing software for detecting coronary artery in-stent restenosis. Methods: CT scans of 14 patients with coronary artery stnets were retrospectively analyzed. The examinations were performed using a 320-detector spiral CT scanner and retrospective ECG gating combined with ECG editing software. The image quality of reconstructed coronary artery in-stents was compared before and after the editing of synchronously recorded ECG. The paired-sample t test was used for statistical analysis. Results: Before ECG editing, arrhythmia and in-stent artifact resulted in image blurring, missing arterial segments, significant stepladder artifacts or non-visualization of the interior of stents. Of 14 cases before ECG editing, in-stent restenosis was detected in 10 and patency in 3. The coronary artery stent and distal bifurcation were delineated in one patient. After ECG editing, the image quality of coronary artery stents was improved with detection of in-stent restenosis (4 cases) including the one case that not evaluable before ECG editing. The average image quality score before ECG editing (2.14±0.86) was significantly (P<0.001) lower than that after ECG editing (3.07±0.73). Conclusion: Retrospective ECG gating combined with ECG editing of 320-detector spiral CT can reduce the artifacts produced by arrhythmia or in-stent swings and improve the imaging quality of coronary artery stents. (authors)

  14. Correlation study of multislice spiral CT and pathology in relationship between solitary pulmonary nodule and bronchus

    International Nuclear Information System (INIS)

    Qiang Jinwei; Ye Xuanguang; Zhou Kangrong; Jiang Yaping; Wang Qun; Xu Songtao; Tan Lijie

    2003-01-01

    Objective: To investigate the relationship between solitary pulmonary nodule (SPN) and bronchus and its value in predicting the nature of nodule. Methods: Continuous volume targeted scans of 0.5 mm collimation were prospectively performed with multislice spiral CT (MSCT) and reconstructed images of MPR, CPR, and SSD in workstation in 75 patients of SPN with ≤3 cm in diameter were acquired. The emphasis was paid on the manifestation of the shapes and patterns of SPN with related bronchi. The results were correlated with macroscopic and microscopic specimens. Results: (1) The SPN-bronchus relationship was shown very clearly in all patients by the designed protocol. CT demonstrated the relations between SPN and bronchus in 44 (86.3%) malignant and 16 (66.7%) benign nodules. There was no statistically significant difference (P=0.065). (2) Five types of SPN-bronchus relationship were identified with MSCT. Type I: bronchus was obstructed abruptly by the SPN, type II: bronchus penetrated into SPN with tapered narrow and interruption, type III: bronchus lumen shown within SPN was patent and intact, type IV: bronchus ran at the periphery of SPN with intact lumen, and type V: bronchus was displaced, compressed, and narrowed by SPN. (3) With respect to the nature of SPN, malignant nodule most commonly showed type I, secondly type IV, and rarely type V. Benign nodule most often showed type V, secondly type I, and no type II. With respect to the pattern, type I, II, and IV patterns were more commonly seen in malignant nodule, whereas type V pattern was seen frequently in benign nodule. Type III pattern was slightly more common in benign cases. Conclusion: Spiral targeted scan of ultra-thin section with MSCT and followed by MPR, CPR, and SSD reconstruction can greatly improve the manifestation of the bronchioles and accurately demonstrate the patterns of SPN-bronchus relationship. Varied patterns are corresponding to certain nodule and reflect definite pathologic changes

  15. Improvement in printing technique of spiral CT three-dimensional colour image

    International Nuclear Information System (INIS)

    Wang Yicheng; Liu Feng; Zhang Ling

    2005-01-01

    Objective: To investigate the printing technique of spiral CT three-dimensional (3D) colour image. Methods: The 3D colour images of 136 patients were printed, with the equipment of Marconi spiral CT, personnel computer, colour ink printer, and network switchboard. Results: All printed images were satisfied by this method. Conclusion: This technique is economic, simple, and useful, and can meet the need for clinical diagnosis and operation. (authors)

  16. Coronary artery imaging with 64-slice spiral CT in atrial fibrillation patients: initial experience

    International Nuclear Information System (INIS)

    Zhou Xuhui; Yan Chaogui; Xie Hongbo; Li Xiangmin; Li Ziping; Meng Quanfei; Chen Xing

    2008-01-01

    Objective: To discuss the clinical value of coronary artery imaging using 64-slice spiral CT in patient with atrial fibrillation. Methods: The images of 31 patients with atrial fibrillation who underwent contrast-enhanced CT coronary angiography were evaluated. The presence of stenosis on each segment of coronary arteries was recorded and their degree of stenosis was measured using the vessel analysis software. Ten patients additionally underwent conventional coronary angiography. The results of conventional coronary angiography were compared with CT coronary angiography of the 10 patients. Results: Image reconstruction was based on absolute timing. The image quality of 364 coronary vessel segments on the images from 31 patients was evaluated and defined as excellent, fine, moderate or poor. The image quality was excellent, fine, moderate and poor in 85, 41, 5, and 8 vessel segments respectively in patient group with heart rate between 47 beat per minent (bpm) and 69 bpm; and in 63, 16, 13, and 15 vessel segments respectively in patent group with heart rate between 70 bpm and 79 bpm;and in 46, 25, 23, and 24 vessel segments in patient group with heart rate between 80 bpm and 105 bpm. There was significant difference among the three patient groups (H=22.08, P<0.01). Comparison was carried out between CT angiographic findings and conventional angiographic findings of the 125 segments of the coronary arteries in the 10 patients who underwent conventional coronary angiography. The sensitivity and specificity of CT angiography for diagnosing vessel with significant coronary stenosis (≥50% narrowing) was 85.0% (17/20) and 95.2% (100/105), respectively. Positive predictive value was 77.3% (17/22), and negative predictive value was 97.1% (100/103). Coronary CTA underestimated the lesions of 3 vessel segments and overestimated the lesions of 5 vessel segments. Conclusion: Coronary artery imaging with 64-slice row CT had clinical value for patients with atrial fibrillation

  17. The usefulness of three-dimensional imaging with spiral CT in the evaluation of upper airway stenosis

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    Jang, Won Ho; Yoon, Dae Young; Bae, Sang Hoon; Rho, Young Soo; Jung, Yin Gyo [Hallym Univ. College of Medicine, Seoul (Korea, Republic of)

    1996-01-01

    To assess the usefulness of three-dimensional (3D) spiral CT imaging in patients with upper airway stenosis. We performed 3D spiral CT imagings in ten patients in whom upper airway stenosis was clinically suspected. Eight of these patients had upper airway stenosis caused by intubation or tracheostomy (n-6), tuberculosis (n=1), or extrinsic compression by a thyroid mass (n=1). Spiral CT scanning (30-second continuous exposure and 90-mm length) was performed with a table speed of 3mm/sec and a section thickness of 3mm. The selected starting point was the epiglottis. The resulting data were reformatted by multiplanar reformation (MPR) and shaded surface display (SSD) with peeling after reconstruction of 2mm interval. In the evaluation of location and extent of stenosis, we compared fidings of 3D imaging with those of baseline axial images (n=10), endoscopy (n=9) and operation (n=4). The locations of stenosis in eight patients were as follows;tracheostoma (n=4), subglottic region (n=3), and larynx (n=1). In all eight, 3D imaging demonstrated the location and extent of stenosis, which exactly correlated with endoscopic and operative findings. In one patient, however, another stenotic area in the tracheal bifurcation was not discovered because this lesion was not included in the field of CT scan. In two patients, the diagnosis on 3D images of no 'stenosis' was comfirmed by clinical findings or operation. No differences in diagnostic accuracy were noted between axial images, MPR, and SSD when evalvating the location and extent of stenosis; vertical extent was shown more easily by 3D imaging than by axial images, however. 3D imaging with spiral CT may be an useful adjunctive method in the evaluation of upper airway stenosis with variable causes.

  18. The usefulness of three-dimensional imaging with spiral CT in the evaluation of upper airway stenosis

    International Nuclear Information System (INIS)

    Jang, Won Ho; Yoon, Dae Young; Bae, Sang Hoon; Rho, Young Soo; Jung, Yin Gyo

    1996-01-01

    To assess the usefulness of three-dimensional (3D) spiral CT imaging in patients with upper airway stenosis. We performed 3D spiral CT imagings in ten patients in whom upper airway stenosis was clinically suspected. Eight of these patients had upper airway stenosis caused by intubation or tracheostomy (n-6), tuberculosis (n=1), or extrinsic compression by a thyroid mass (n=1). Spiral CT scanning (30-second continuous exposure and 90-mm length) was performed with a table speed of 3mm/sec and a section thickness of 3mm. The selected starting point was the epiglottis. The resulting data were reformatted by multiplanar reformation (MPR) and shaded surface display (SSD) with peeling after reconstruction of 2mm interval. In the evaluation of location and extent of stenosis, we compared fidings of 3D imaging with those of baseline axial images (n=10), endoscopy (n=9) and operation (n=4). The locations of stenosis in eight patients were as follows;tracheostoma (n=4), subglottic region (n=3), and larynx (n=1). In all eight, 3D imaging demonstrated the location and extent of stenosis, which exactly correlated with endoscopic and operative findings. In one patient, however, another stenotic area in the tracheal bifurcation was not discovered because this lesion was not included in the field of CT scan. In two patients, the diagnosis on 3D images of no 'stenosis' was comfirmed by clinical findings or operation. No differences in diagnostic accuracy were noted between axial images, MPR, and SSD when evalvating the location and extent of stenosis; vertical extent was shown more easily by 3D imaging than by axial images, however. 3D imaging with spiral CT may be an useful adjunctive method in the evaluation of upper airway stenosis with variable causes

  19. Carotid stenosis: a comparison between MR and spiral CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Magarelli, N.; Carriero, A.; Bonomo, L. [Institute of Radiology, University ``G. D`Annunzio``, Chieti (Italy); Scarabino, T.; Simeone, A.L.; Florio, F. [IRCCS, Foggia (Italy); Salvolini, U. [Department of Neuroradiology, University of Ancona (Italy)

    1998-06-01

    We performed a preliminary study comparing three-dimensional time-of-flight (3 D TOF) magnetic resonance angiography (MRA) and spiral CT angiography (SCTA) in the detection and assessment of internal carotid artery stenosis. Digital subtraction angiography (DSA) was the reference examination. We examined 20 patients with signs of cerebrovascular insufficiency, who underwent MRA, SCTA and DSA within a 3 day period. Both internal carotid arteries were assessed by three blinded readers for degree of stenosis at two different levels (bulb and remaining section) giving a total of 80 assessments. Interobserver variability, sensitivity, specificity, diagnostic accuracy, concordance, overestimation and underestimation were assessed. Interobserver variability was not statistically significant. MRA showed higher sensitivity, specificity, diagnostic accuracy and concordance than SCTA (92.0 % vs 80.8 %, 98.2 % vs 96.4 %, 96.3 % vs 91.3 % and 96.0 % vs 88.0 %, respectively). MRA gave rise to a 5.0 % overestimation rate, whereas SCTA occasioned a 7.5 % underestimation rate. These differences are not statistically significant. These results suggest that MRA is a more useful, noninvasive modality for assessment of the internal carotid artery with a more than 70 % stenosis. (orig.) With 6 figs., 4 tabs., 17 refs.

  20. Carotid stenosis: a comparison between MR and spiral CT angiography

    International Nuclear Information System (INIS)

    Magarelli, N.; Carriero, A.; Bonomo, L.; Scarabino, T.; Simeone, A.L.; Florio, F.; Salvolini, U.

    1998-01-01

    We performed a preliminary study comparing three-dimensional time-of-flight (3 D TOF) magnetic resonance angiography (MRA) and spiral CT angiography (SCTA) in the detection and assessment of internal carotid artery stenosis. Digital subtraction angiography (DSA) was the reference examination. We examined 20 patients with signs of cerebrovascular insufficiency, who underwent MRA, SCTA and DSA within a 3 day period. Both internal carotid arteries were assessed by three blinded readers for degree of stenosis at two different levels (bulb and remaining section) giving a total of 80 assessments. Interobserver variability, sensitivity, specificity, diagnostic accuracy, concordance, overestimation and underestimation were assessed. Interobserver variability was not statistically significant. MRA showed higher sensitivity, specificity, diagnostic accuracy and concordance than SCTA (92.0 % vs 80.8 %, 98.2 % vs 96.4 %, 96.3 % vs 91.3 % and 96.0 % vs 88.0 %, respectively). MRA gave rise to a 5.0 % overestimation rate, whereas SCTA occasioned a 7.5 % underestimation rate. These differences are not statistically significant. These results suggest that MRA is a more useful, noninvasive modality for assessment of the internal carotid artery with a more than 70 % stenosis. (orig.)

  1. Colorectal carcinoma: preoperative staging with water enema spiral CT

    International Nuclear Information System (INIS)

    Guan Sheng; Gao Jianbo; Li Yintai; Chen Xuejun; Yang Xuehua; Yang Xiaopeng; Cheng Jingliang

    2001-01-01

    Objective: To determine the value and limitation of water enema spiral CT (WESCT) in staging of colorectal carcinoma. Methods: Forty-eight patients with histologically proven rectum or colon carcinoma were included in this study. All of them were examined by SCT, and the preoperative staging of TNM and Duke were used based on the findings of SCT. The results of WESCT were compared with those of surgical and pathological examination in all cases. Results: All lesions in the 47 cases were demonstrated clearly by WESCT and the sensitivity was 97.9%; 39 cases of 48 patients were correctly staged with TNM and 42 cases with Duke, the accuracy was 81.3% and 87.5% respectively, which were higher than the overall 50 % accuracy reported by references; (3) The accuracy of WESCT was 89.6% (43/48) in T stage and 81.3% (39/48) in N stage. Three cases in M stage were all diagnosed correctly; Conclusion: WESCT scan is a better method of depicting the colorectal carcinoma. It allows for accurate depiction and staging of colorectal carcinoma, especially detecting the invasion of adjacent tissues and distant metastasis. It is the best imaging method for staging the colorectal carcinoma . However the value of WESCT for early T staging in colorectal carcinoma and minute metastasis of lymph nodes or liver is limited

  2. The value of spiral CT scan on fracture of ankle joint and tarsal bones

    International Nuclear Information System (INIS)

    Li Zhaoli; Liang Jingyin; Pan Zhifeng

    2009-01-01

    Objective: To study the value of spiral CT scan on the fracture of ankle joint and tarsal bones. Methods: 43 cases with the fracture of ankle joint and tarsal bones were collected and analyzed. All the cases were examined by plain film radiography and spiral CT thin slice scan. Multi-planar reformation (MPR), surface shaded display (SSD) and other techniques of image post-processing were performed in 35 cases of them. Results: Spiral CT scan could demonstrate more fractures than plain film radiography in 28 cases(65.1%). There are 15 cases (34.9%) which are normal in plain film radiography but abnormal in Spiral CT scan. Spiral CT could demonstrate the different length, width, direction and number of linear low density shadow. SSD and MPR were performed again in the cases with avulsion fracture and fragmental fracture to demonstrate the fracture direction and the shape, size and location of fragments more clearly. Conclusion: Spiral CT thin slice scan with image post-processing techniques can play an important role in fracture of ankle joint and tarsal bones. (authors)

  3. The value of multislice spiral CT in transcatheter arterial chemoembolization of the hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Li Zhigang; Zhao Junjing; Shi Gaofeng; Li Shunzong; Han Pengyin; Yang Guang; Liang Guoqing; Wang Hongguang; Huang Jingxiang

    2006-01-01

    Objective: To evaluate the value of multislice spiral CT (MSCT) in transcatheter arterial chemoembolization of the hepatocellular carcinoma. Methods: MSCT were performed in 54 cases of HCC before interventional procedure. CT findings of hepatic artery phase, portal venous phase and hepatic venous phase were observed respectively. CTA were done in 12 cases, the anatomy of celiac artery and its branches were observed. The schemes of interventional therapy were worked out according to the findings of MSCT. The demonstration of lesions and its complications were compared between CT and DSA. Reconstruction of celiac artery branches used the technique of VRT, MIP or MPR. Results: MSCT showed 225 lesions, 10 cases tumor thrombosis of portal vein, 1 case hepatic arteriovenous shunt, and 13 cases hepatic arterioportal shunt. Positive rate of MSCT in showing number of tumor lesions, tumor thrombosis in portal vein was slightly higher than that of DSA, but there was no significant difference (P>0.05). Showing of 3D reconstruction of celiac artery branches in CTA is better than that in DSA, Showing of angles between celiac artery and abdominal aorta in MSCT is more convenient than that in DSA. MSCT showed 5 cases hepatic artery original abnormality. The results were in accord with that in DSA. Five cases were demonstrated of multiple supply blood vessels of tumor in MSCT, It was slightly lower than that of DSA. Conclusion: MSCT is of importance for guidance of transcatheter arterial chemoembolization of the hepatocellular carcinoma, delay time of CT scan is the key to the showing of lesions and blood vessels. (authors)

  4. Enhancement pattern of small hepatic hemangioma: findings on multiphase spiral CT and dynamic MRI

    International Nuclear Information System (INIS)

    Choi, Byung In; Lee, Seung Koo; Kim, Myeong Jin; Chung, Jae Joon; Yoo, Hyung Sik; Lee, Jong Tae

    1999-01-01

    To compare the enhancement characteristics of small hemangiomas seen on multiphase spiral CT and dynamic MR imaging. Thirteen patients with 20 hepatic hemangiomas less than 25mm in diameter underwent both multiphase spiral CT and dynamic MR imaging. All lesions were assigned to one of three classified into 3 categories according to the enhancement pattern seen on multiphase spiral CT : typical delayed pooling, atypical early enhancement, or continuous low attenuation. The enhancement patterns seen on spiral CT and on dynamic MRI were correlated. On CT scans, ten lesions (50%) showed delayed pooling. Six (30%) showed early arterial enhancement and four (20%) showed continuous low attenuation. On delayed-phase MRI, all lesions showed delayed high signal intensity compared to adjacent liver parenchyma. Four of six lesions with early enhancement on CT showed peripheral globular enhancement on early arterial-phase MRI. On multiphase spiral CT scans, small hemangiomas can show variable atypical enhancement features. In this situation, contrast-enhanced dynamic MRI is helpful for the diagnosis of hemangiomas

  5. The role of spiral CT in patients with intermediate probability V/Q scans: can spiral CT replace pulmonary angiography?

    International Nuclear Information System (INIS)

    Vu, T.; Glenn, D.; Lovett, I.; Moses, J.; Wadhwa, S.S.; Nour, R.

    2000-01-01

    Full text: Spiral CT (SCT) has been advocated as a replacement for pulmonary angiography (PA)in patients with intermediate probability (IP) ventilation-perfusion lung scans (V/Q). More generally it has been proposed as a replacement for V/Q to detect Pulmonary Embolism. This study investigates the accuracy of SCT in the IP patient group 31 patients with IP scans (Modified PIOPED criteria) who were not at high risk of contrast nephrotoxicity were enrolled to have both SCT and PA within the 24 hours following their V/Q. Patients were classified as IP due to a single segmental mismatch (n=7) or a matched V/Q abnormality corresponding to CXR opacity (n=21), or both (n=3). PA is the gold standard for the detection of PE. SCT was read by an experienced radiologist blinded to the PA results. SCT was performed according to standard protocol. All SCT were technically satisfactory for interpretation. Pulmonary embolism was present in 9/31 patients (29%). Of the patients with PE detected by PA, SCT was positive in 4 (44% sensitivity). Of the 22 patients who did not have PE, SCT was negative in 21 and positive in one (96% specificity). In conclusion SCT has limited sensitivity for the detection of PE in patients with IP lung scans. SCT may not be an adequate replacement for PA. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  6. CT-based virtual tracheobronchoscopy in children - comparison with axial CT and multiplanar reconstruction: preliminary results

    International Nuclear Information System (INIS)

    Sorantin, Erich; Lindbichler, Franz; Eber, Ernst; Schimpl, Guenther

    2002-01-01

    Background: 3D post-processing of spiral-CT (S-CT) data using perspective projection allows the generation of virtual views similar to endoscopy. Objective: To evaluate whether simultaneous reading of axial S-CT, multiplanar reconstruction (MPR) and virtual tracheobronchoscopy (VTB) is more precise and accurate than reading of axial S-CT and MPR alone in paediatric patients. Materials and methods: S-CT studies of 15 symptomatic and 4 normal patients were investigated. Two radiologists independently read two sets of images for airway abnormalities: first axial CT and MPR, followed by axial CT, MPR and VTB. A final decision was later made by consensus. All results were compared to fibre-optic bronchoscopy (FTB). Interobserver agreement was used as an indicator of precision for the display technique used. Results: At reading of axial S-CT and MPR an interobserver agreement of 89.5% (κ=0.776, P<0.00103) was found. Based on the consensus decision, a diagnostic accuracy of 89.5% at a sensitivity 86.6% and specificity of 100% (κ=0.776, 95% CI 0.491-1.062, P<0.00103) was achieved. At reporting on axial S-CT, MPR and VTB, all cases were classified correctly by both readers, indicating 100% accuracy, interobserver agreement, sensitivity and specificity (κ=1.00, 95% CI 1.0-1.0, P<0.000258). Conclusions: The simultaneous display of axial S-CT, MPR and VTB raises the precision, accuracy and sensitivity of radiological reports. (orig.)

  7. A dynamic approach to identifying desired physiological phases for cardiac imaging using multislice spiral CT

    International Nuclear Information System (INIS)

    Vembar, M.; Garcia, M.J.; Heuscher, D.J.; Haberl, R.; Matthews, D.; Boehme, G.E.; Greenberg, N.L.

    2003-01-01

    In this investigation, we describe a quantitative technique to measure coronary motion, which can be correlated with cardiac image quality using multislice computed tomography (MSCT) scanners. MSCT scanners, with subsecond scanning, thin-slice imaging (sub-millimeter) and volume scanning capabilities have paved the way for new clinical applications like noninvasive cardiac imaging. ECG-gated spiral CT using MSCT scanners has made it possible to scan the entire heart in a single breath-hold. The continuous data acquisition makes it possible for multiple phases to be reconstructed from a cardiac cycle. We measure the position and three-dimensional velocities of well-known landmarks along the proximal, mid, and distal regions of the major coronary arteries [left main (LM), left anterior descending (LAD), right coronary artery (RCA), and left circumflex (LCX)] during the cardiac cycle. A dynamic model (called the 'delay algorithm') is described which enables us to capture the same physiological phase or 'state' of the anatomy during the cardiac cycle as the instantaneous heart rate varies during the spiral scan. The coronary arteries are reconstructed from data obtained during different physiological cardiac phases and we correlate image quality of different parts of the coronary anatomy with phases at which minimum velocities occur. The motion characteristics varied depending on the artery, with the highest motion being observed for RCA. The phases with the lowest mean velocities provided the best visualization. Though more than one phase of relative minimum velocity was observed for each artery, the most consistent image quality was observed during mid-diastole ('diastasis') of the cardiac cycle and was judged to be superior to other reconstructed phases in 92% of the cases. In the process, we also investigated correlation between cardiac arterial states and other measures of motion, such as the left ventricular volume during a cardiac cycle, which earlier has been

  8. Evaluation of radiation exposure with singleslice- and a multislice-spiral CT system (a phantom study)

    International Nuclear Information System (INIS)

    Giacomuzzi, S.M.; Rieger, M.; Lottersberger, C.; Peer, S.; Peer, R.; Buchberger, W.; Bale, R.; Mallouhi, A.; Jaschke, W.; Torbica, P.; Perkmann, R.

    2001-01-01

    The purpose of study was to compare patient dose applying singleslice- and multislice-spiral CT. Methods: The examinations were performed with a singleslice-spiral CT (Highspeed Advantage; GE Medical Systems; Milwaukee, USA) and with a multislice CT systems (LightSpeed QX/i GE Medical Systems; Milwaukee, USA). For the determination of the radiation exposure (absorbed dose) a selection of most executed protocols (thorax-helical, abdomen-helical, petrous bone-axial, head-axial) were simulated using an Alderson Rando Phantom. The dose was determined by means of lithiumfluorid-thermoluminescence dosimeters (TLD-GR 200). Results: For thorax and abdomen protocols higher energy dose values could be found using a multislice CT. On the average the energy dose values were increased by 2.6 on an average in relation to single slice spiral CT. The energy dose values of the multisclice CT using head protocols could be reduced by 30% in relation to single slice spiral CT due to suitable parameter selections. The energy dose applying a petrous bone protocol resulted in an average increase by a factor 1.5 using a multislice CT. Conclusion: Using the new multislice CT technique protocol strategies must be optimized regarding the patient doses. Users can operate critically in the sense of the radiation protection only if they are aware of the occurring dose amounts to the patient. (orig.) [de

  9. Shallow and deep breath lung tumor volume as estimated by spiral volumetric CT in comparison to standard axial CT using virtual simulation

    International Nuclear Information System (INIS)

    Quader, M.A.; Kalend, A.M.; Deutsch, M.; Greenberger, J.S.

    1995-01-01

    Purpose/Objective: In order to assess an individual patient tumor volume (TV) margins that are sufficient to design a beam-eye-view (BEW) conformal portal, the radiographic extent of gross tumor volume (GTV) dimensions and its fluctuation with breathing are measured by fast spiral CT scanning of patients treated for Stage II, III lung cancers using 5-6 field multi-collimated conformal beams. Materials and Methods: Over the course of conformal radiotherapy for lung cancer, a full thorax CT scans of the patient were taken by conventional axial CT scanning with patients immobilized in the treatment position and breathing normally. Patient(s) with good pulmonary function test (PFT) status were selected to perform deep breathing and re-scanned by fast spiral techniques in order to re-acquire the tomographic variation in the (GTV) with breathing. A Picker spiral ZAP-100 software running on the AQSim-PQ-2000 was used with a variable helical pitch of 1.0, 1.5 and 2.0. The variable pitch spirals were limited to tumor bed, diaphragm and lung apex area for measurements. Effect of breathing motion along x,y,z direction were then assessed for each beam-eye-view portal as seen in digitally reconstructed radiography (DRR) at the treated gantry angle. Results: Comparison of axial and spiral scans shows the progression of lung and diaphram motion with breathing can be gauged better in spiral scans. The movement of the diaphragm during shallow breathing has been found to be 2-3cm by measuring the distance between the most inferior and superior slices where diaphragm is present. The variation of the tumor dimensions along AP/PA and lateral direction seems to be less sensitive to breathing than those along inferior-superior direction. Conclusion: The fast spiral CT scanning is sensitive to patient lung motion and can be used to determine the fluctuations of the gross tumor volume with breathing. The extent of the fluctuation is location dependent and increases as one moves from the

  10. Research of ART method in CT image reconstruction

    International Nuclear Information System (INIS)

    Li Zhipeng; Cong Peng; Wu Haifeng

    2005-01-01

    This paper studied Algebraic Reconstruction Technique (ART) in CT image reconstruction. Discussed the ray number influence on image quality. And the adopting of smooth method got high quality CT image. (authors)

  11. Comparison of spiral CT angiography with conventional digital subtraction angiography in the evaluation of renal transplant donors: a pilot study

    International Nuclear Information System (INIS)

    Chu, C.; Young, N.; Lau, H.

    2001-01-01

    Conventional digital subtraction renal arteriography (IA-DSA) has been traditionally used as the preoperative imaging modality for assessment of renal vascular anatomy for renal transplant donors. This study evaluates the potential use of spiral CT angiography in replacing IA-DSA in the preoperative assessment of this group of patients. Seven patients underwent both spiral CT angiography and IA-DSA between October 1997 and April 1998. It is concluded that spiral CT angiography can demonstrate the number, length and location of renal arteries and it is suggested that spiral CT angiography can potentially replace IA-DSA in the preoperative assessment of renal donors. Copyright (2001) Blackwell Science Pty Ltd

  12. Three-dimensional reconstruction of the biliary tract using spiral computed tomography. Three-dimensional cholangiography

    International Nuclear Information System (INIS)

    Gon, Masanori; Ogura, Norihiro; Uetsuji, Shouji; Ueyama, Yasuo

    1995-01-01

    In this study, 310 patients with benign biliary diseases, 20 with gallbladder cancer, and 8 with biliary tract carcinoma underwent spiral CT (SCT) scanning at cholangiography. Depiction rate of the shape of the conjunction site of the gallbladder and biliary tract was 27.5% by conventional intravenous cholangiography (DIC), 92.5% by ERC, and 90.0% by DIC-SCT. Abnormal cystic duct course was admitted in 14.1%. Multiplanar reconstruction by DIC-SCT enabled identification of the common bile duct and intrahepatic bile duct stone. Three-dimensional reconstruction of DIC-SCT was effective in evaluating obstruction of the anastomosis or passing condition of after hepatico-jejunostomy. Two-dimensional SCT images through PTCD tube enabled degree of hepatic invasion in bile duct cancer, and three-dimensional images were useful in grasping the morphology of the bile duct branches near the obstruction site. DIC-SCT is therefore considered a useful procedure as non-invasive examination of bile duct lesions. (S.Y.)

  13. Adaptive statistical iterative reconstruction technology in the application of PET/CT whole body scans

    International Nuclear Information System (INIS)

    Xin Jun; Zhao Zhoushe; Li Hong; Lu Zhe; Wu Wenkai; Guo Qiyong

    2013-01-01

    Objective: To improve image quality of low dose CT in whole body PET/CT using adaptive statistical iterative reconstruction (ASiR) technology. Methods: Twice CT scans were performed with GE water model,scan parameters were: 120 kV, 120 and 300 mA respectively. In addition, 30 subjects treated with PET/CT were selected randomly, whole body PET/CT were performed after 18 F-FDG injection of 3.70 MBq/kg, Sharp IR+time of flight + VUE Point HD technology were used for 1.5 min/bed in PET; CT of spiral scan was performed under 120 kV using automatic exposure control technology (30-210 mA, noise index 25). Model and patients whole body CT images were reconstructed with conventional and 40% ASiR methods respectively, and the CT attenuation value and noise index were measured. Results: Research of model and clinical showed that standard deviation of ASiR method in model CT was 33.0% lower than the conventional CT reconstruction method (t =27.76, P<0.01), standard deviation of CT in normal tissues (brain, lung, mediastinum, liver and vertebral body) and lesions (brain, lung, mediastinum, liver and vertebral body) reduced by 21.08% (t =23.35, P<0.01) and 24.43% (t =16.15, P<0.01) respectively, especially for normal liver tissue and liver lesions, standard deviations of CT were reduced by 51.33% (t=34.21, P<0.0) and 49.54% (t=15.21, P<0.01) respectively. Conclusion: ASiR reconstruction method was significantly reduced the noise of low dose CT image and improved the quality of CT image in whole body PET/CT, which seems more suitable for quantitative analysis and clinical applications. (authors)

  14. Spiral hydro-CT of the pancreas in the thin-slice method

    International Nuclear Information System (INIS)

    Richter, G.M.; Simon, C.; Hoffmann, V.; DeBernardinis, M.; Seelos, R.; Senninger, N.; Kauffmann, G.W.

    1996-01-01

    In an open prospective study, 151 patients with a suspected pancreatic neoplasm based on clinical, laboratory or other imaging data were examined between May 94 and October 95. Our newly developed Hydro-CT methodology included intravenous injection of 40 mg N-butylscopolaminium bromide (Buscopan) for intestinal paralysis, gastric and duodenal wall distension by oral administration of an average of 1.5 l warm tap water, 30 RAO patient positioning, an individualized contrast injection technique as determined beforehand by time-to-peak measurement in the portal vein and thin-slice spiral CT (3 mm increment, 6 mm table feed and 3 mm secondary reconstruction). A detailed evaluation form was used to assess (1) tumor detection rate, (2) differentiation of malignant versus benign disease, (3) differential diagnosis, and (4) accuracy of assessment of resectability by identification of infiltration into adjacent organs and vessel structures relevant for resectability such as splenic, superior mesenteric, portal vein and celiac trunk, superior mesenteric, splenic and hepatic arteries. As the gold standard for positive tumor detection surgery and microscopic diagnosis were used, and for negative tumor detection an event-free survival of 6 months. Almost all examinations were well tolerated. In only 4% was on-site administration of a gastric tube required because of vomiting. In 2% of the patients a slight allergic reaction to be contrast medium was seen. The prevalence of a pancreatic neoplasm was 38%. In tumor detection Hydro-CT reached an overall accuracy of 97.4% with a sensitivity of 100% and a specificity of 95.9%. In the differentiation of benign versus malignant disease Hydro-CT reached an overall accuracy of 89.7% with a sensitivity of 92.5% and a specificity of 83.3%. The prevalence of a pancreatic carcinoma was 24%; 4% other malignant tumors were found (distal common bile duct carcinoma, cystadenocarcinoma). (orig./MG) [de

  15. Evaluation of hepatic alveolar echinococcosis with multi-slices spiral CT

    International Nuclear Information System (INIS)

    Liu Wenya; Lou Jianru; Xing Yan; Wang Jing; Wang Haitao

    2005-01-01

    Objective: To analyze the multi-slices spiral CT (MSCT) findings of hepatic alveolar echinococcosis (HAE), and to evaluate the value of MSCT for diagnosis of HAE. Methods: Twenty-six cases with HAE were scanning by MSCT. The raw data were transmitted to advanced workstation for reconstruction imaging. Correlated studies were made between the CT features and pathology or other imaging results. Results: Altogether 28 lesions were detected. They all revealed as heterogeneous hypodense mass with ill-defined boundary in plain CT but were easily being distinguished from surrounding parenchyma after contrast medium injection. Characteristics of the lesions include different amount of calcification (26/26), liquefied necrosis in center area (20/26), peripheral lacunae or alveolar signs (15/26 ), compensatory hypertrophy of healthy hepatic part (18/26) and the retraction in the involved hepatic lobe or segment (12/26). The lesions that located at or extended to hepatic hilum caused dilatation of intra-hepatic biliary ducts (9/26), splenomegaly (12/26 ), and ascites (1/26). MSCT angiography (CTA) depicted signs of abnormalities of hepatic vessels such as compression, displacement, encasement and occlusion. Compared with findings of operation, the sensitivity, specificity and positive prediction value of CTA for evaluating the hepatic artery system disorders were 88%, 96% and 93%, respectively; and for portal venous system were 95%, 100% and 95%, respectively; while for hepatic venous system were 96%, 86% and 96%, respectively. Conclusion: MSCT is able to comprehensive display the CT features and vessels complication of HAE. It provides reliable imaging for both accuracy diagnosis and proper treatment of the disease. (authors)

  16. Measurement and analysis of cardiopulmonary vascular in Lanzhou healthy adults with multislice spiral CT

    International Nuclear Information System (INIS)

    Shi Xiaonan; Guo Shunlin

    2013-01-01

    Objective: To constitute a normal standard of cardiopulmonary vascular diameter and size of normal adult in Lanzhou, and to compared with the other's data reported in the previous bibliography by measuring diameter and area of cardiopulmonary artery lumen of the healthy adults in Lanzhou with multislice spiral CT (MSCT). Methods: Three hundred Lanzhou adults with no cardiopulmonary disease were equally assigned to 3 groups according to their age (A group: 18-39 years, B group: 40-60 years, C group: 61-80 years; 50 females and 50 males in each group). CT data were acquired at the end of deep inspiration phase and measurements were done on 3D reconstruction image with precise landmarks. All the results were statistically analyzed. Results: The diameters and areas of the main pulmonary artery left pulmonary artery right pulmonary artery ascending aorta and descending aorta differed significantly among the 3 groups (P<0.05). In groups B and C, there were significant differences in diameters and areas of pulmonary artery left pulmonary artery and right pulmonary between different genders (P<0.05). Conclusion: Imaging standard is provided for Lanzhou adult in early diagnosis of cardiopulmonary disease. The diameters and areas of main pulmonary artery left pulmonary artery and right pulmonary artery of Lanzhou healthy adults are different from that of other regions. It may be related to the geographical environment and the state of air pollution in Lanzhou. (authors)

  17. First results of spiral CT angiography in the evaluation of carotid artery stenosis

    International Nuclear Information System (INIS)

    Link, J.; Mueller-Huelsbeck, S.; Brossmann, J.; Grabener, M.; Voss, C.; Heller, M.

    1995-01-01

    To determine the value of spiral CT angiography in Maximum Intensity Projection (MIP)-technique for evaluation of carotid artery stenosis. A comparison of the MIP technique with intraarterial DSA was done in 24 patients with 40 stenoses. Quantification of stenosis was determined according to the NASCET study: mild (0-29%), moderate (30-69%), severe (70-99%) and occlusion (100%). Totally the correlation of spiral CT angiography with DSA was 80% (r=0.93; p=0.0001). In the moderate stenosis group (r=1; p=0.1573), severe stenosis group (r=0.89; p=0.002) and the occlusion group (r=1; p=0.0009) there was a good correlation with DSA. In the mild stenosis group (r=0.55; p=0.0704) correlation of spiral CT angiography with DSA was poor. Spiral CT angiography allows an excellent delineation of calcifications. Tandem lesions and collateral flow cannot be shown with spiral CT angiography. (orig./MG) [de

  18. Three-dimensional reconstruction of CT images

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Toshiaki; Kattoh, Keiichi; Kawakami, Genichiroh; Igami, Isao; Mariya, Yasushi; Nakamura, Yasuhiko; Saitoh, Yohko; Tamura, Koreroku; Shinozaki, Tatsuyo

    1986-09-01

    Computed tomography (CT) has the ability to provide sensitive visualization of organs and lesions. Owing to the nature of CT to be transaxial images, a structure which is greater than a certain size appears as several serial CT images. Consequently each observer must reconstruct those images into a three-dimensional (3-D) form mentally. It has been supposed to be of great use if such a 3-D form can be described as a definite figure. A new computer program has been developed which can produce 3-D figures from the profiles of organs and lesions on CT images using spline curves. The figures obtained through this method are regarded to have practical applications.

  19. CT Imaging of facial trauma. Role of different types of reconstruction. Part I - bones

    International Nuclear Information System (INIS)

    Myga-Porosilo, J.; Sraga, W.; Borowiak, H.; Jackowska, Z.; Kluczewska, E.; Skrzelewski, S.

    2011-01-01

    Background: Injury to the facial skeleton and the adjoining soft tissues is a frequently occurring condition. The main aim of this work was to assess the value of multiplanar and three-dimensional (3D) reconstruction computed tomography (CT) images obtained by using multi-detector row technology in spiral data acquisition in patients with facial skeleton injury. The authors attempted to answer the following questions: Are there particular mechanisms and types of injuries or locations of fractures which can be diagnosed significantly more effectively by conducting additional multiplanar image reconstructions? Do 3D image reconstructions contribute to the diagnostic process, to what extent? Compared to other imaging techniques, is the spiral CT data acquisition a more convenient for the patient and a faster investigation method of diagnosing post-injury lesions involving the facial skeleton? Material/Methods: Sixty-seven patients diagnosed with injury to the facial skeleton were referred for emergent CT scanning. Each patient underwent a CT scan with the use of a GE HiSpeed Qx/i scanner. The scans were conducted with the use of spiral data acquisition technique in the transverse plane. The following secondary image reconstructions were conducted for each patient: a two dimensional (2D) multiplanar reconstruction (MPR), maximum intensity projection (MIP), and 3D volume rendering (VR). Post-injury lesions of the facial skeleton were assessed and the presence of any loose displaced bone fragments was taken into consideration. Results: As far as fracture imaging is concerned, the 2D image reconstruction and volume rendering proved to be the most effective in the majority of locations. 3D image reconstructions proved the most sensitive in most cases of loose displaced bone fragments, except for fine structures such as the ethmoid bone and the inferior orbital wall. Conclusions: 1. Multiplanar computer reconstructions increase the effectiveness of visualisation of

  20. Spiral CT angiography of middle cerebral artery stenoses

    International Nuclear Information System (INIS)

    Lehmann, K.J.; Neff, K.W.; Ries, S.; Sommer, A.; Steinke, W.; Georgi, M.

    1996-01-01

    Transcranial Doppler ultrasonography (TCD) and magnetic resonance angiography (MRA) are well-established techniques for ascertaining intracranial obstructive artery disease. The short examination time required for additional helical CT angiography (CTA) allows quick management of emergency patients already undergoing native CT. However, today the ability of CTA to detect stenoses of the middle cerebral artery (MCA) has not been proven. To analyse the value of CTA in the classification of atherosclerotic disease 23 MCA stenoses confirmed by TCD and MRA were investigated. CTA was performed on a Hispeed advantage scanner (GE) using a bolus injection of 70 ml KM and 40 ml NaCl with a flow rate of 2.5 ml/s, a thickness of 1 mm, a pitch of 1.5 and a 1 mm increment. CTA was presented as maximum intensity projection (MIP) and as multi-projection volume reconstruction (MPVR). A three-step classification of stenosis was compared with the results of TCD and MRA. Good opacification of the MCA was achieved in M1 and M2 segments in all patients. Classification of stenosis by CTA agreed with MRA and TCD in 14 cases; 7 stenoses were assigned to a lower classification by CTA. Two lowgrade stenoses could not be proven by CTA. Although MIP and MPVR yield the same result in stenosis classification MPVR showed a sharper image quality. In contrast to MRA, veins were highly opacified in CTA. Artery and vein were sometimes superimposed, which had to be avoided by changing the projection angle. Medium- and high-grade MCA stenoses can be demonstrated by CTA quickly and reliably. Compared to MRA and TCD, CTA provides lower grading of stenosis. (orig.) [de

  1. Hyaline cartilage thickness in radiographically normal cadaveric hips: comparison of spiral CT arthrographic and macroscopic measurements.

    Science.gov (United States)

    Wyler, Annabelle; Bousson, Valérie; Bergot, Catherine; Polivka, Marc; Leveque, Eric; Vicaut, Eric; Laredo, Jean-Denis

    2007-02-01

    To assess spiral multidetector computed tomographic (CT) arthrography for the depiction of cartilage thickness in hips without cartilage loss, with evaluation of anatomic slices as the reference standard. Permission to perform imaging studies in cadaveric specimens of individuals who had willed their bodies to science was obtained from the institutional review board. Two independent observers measured the femoral and acetabular hyaline cartilage thickness of 12 radiographically normal cadaveric hips (from six women and five men; age range at death, 52-98 years; mean, 76.5 years) on spiral multidetector CT arthrographic reformations and on coronal anatomic slices. Regions of cartilage loss at gross or histologic examination were excluded. CT arthrographic and anatomic measurements in the coronal plane were compared by using Bland-Altman representation and a paired t test. Differences between mean cartilage thicknesses at the points of measurement were tested by means of analysis of variance. Interobserver and intraobserver reproducibilities were determined. At CT arthrography, mean cartilage thickness ranged from 0.32 to 2.53 mm on the femoral head and from 0.95 to 3.13 mm on the acetabulum. Observers underestimated cartilage thickness in the coronal plane by 0.30 mm +/- 0.52 (mean +/- standard error) at CT arthrography (P cartilage thicknesses at the different measurement points was significant for coronal spiral multidetector CT arthrography and anatomic measurement of the femoral head and acetabulum and for sagittal and transverse CT arthrography of the femoral head (P cartilage thickness from the periphery to the center of the joint ("gradients") were found by means of spiral multidetector CT arthrography and anatomic measurement. Spiral multidetector CT arthrography depicts cartilage thickness gradients in radiographically normal cadaveric hips. (c) RSNA, 2007.

  2. Parallel CT image reconstruction based on GPUs

    International Nuclear Information System (INIS)

    Flores, Liubov A.; Vidal, Vicent; Mayo, Patricia; Rodenas, Francisco; Verdú, Gumersindo

    2014-01-01

    In X-ray computed tomography (CT) iterative methods are more suitable for the reconstruction of images with high contrast and precision in noisy conditions from a small number of projections. However, in practice, these methods are not widely used due to the high computational cost of their implementation. Nowadays technology provides the possibility to reduce effectively this drawback. It is the goal of this work to develop a fast GPU-based algorithm to reconstruct high quality images from under sampled and noisy projection data. - Highlights: • We developed GPU-based iterative algorithm to reconstruct images. • Iterative algorithms are capable to reconstruct images from under sampled set of projections. • The computer cost of the implementation of the developed algorithm is low. • The efficiency of the algorithm increases for the large scale problems

  3. Fast parallel algorithm for CT image reconstruction.

    Science.gov (United States)

    Flores, Liubov A; Vidal, Vicent; Mayo, Patricia; Rodenas, Francisco; Verdú, Gumersindo

    2012-01-01

    In X-ray computed tomography (CT) the X rays are used to obtain the projection data needed to generate an image of the inside of an object. The image can be generated with different techniques. Iterative methods are more suitable for the reconstruction of images with high contrast and precision in noisy conditions and from a small number of projections. Their use may be important in portable scanners for their functionality in emergency situations. However, in practice, these methods are not widely used due to the high computational cost of their implementation. In this work we analyze iterative parallel image reconstruction with the Portable Extensive Toolkit for Scientific computation (PETSc).

  4. Iterative reconstruction reduces abdominal CT dose

    International Nuclear Information System (INIS)

    Martinsen, Anne Catrine Trægde; Sæther, Hilde Kjernlie; Hol, Per Kristian; Olsen, Dag Rune; Skaane, Per

    2012-01-01

    Objective: In medical imaging, lowering radiation dose from computed tomography scanning, without reducing diagnostic performance is a desired achievement. Iterative image reconstruction may be one tool to achieve dose reduction. This study reports the diagnostic performance using a blending of 50% statistical iterative reconstruction (ASIR) and filtered back projection reconstruction (FBP) compared to standard FBP image reconstruction at different dose levels for liver phantom examinations. Methods: An anthropomorphic liver phantom was scanned at 250, 185, 155, 140, 120 and 100 mA s, on a 64-slice GE Lightspeed VCT scanner. All scans were reconstructed with ASIR and FBP. Four readers evaluated independently on a 5-point scale 21 images, each containing 32 test sectors. In total 672 areas were assessed. ROC analysis was used to evaluate the differences. Results: There was a difference in AUC between the 250 mA s FBP images and the 120 and 100 mA s FBP images. ASIR reconstruction gave a significantly higher diagnostic performance compared to standard reconstruction at 100 mA s. Conclusion: A blending of 50–90% ASIR and FBP may improve image quality of low dose CT examinations of the liver, and thus give a potential for reducing radiation dose.

  5. The application of spiral-CT and 3D-imaging of airway for observation of efficacy and complication after tracheobronchial stent placement

    International Nuclear Information System (INIS)

    Wei Ning; Xu Hao; Zu Maoheng; Gu Yuming; Li Gang; Zhang Qingqiao; Xu Wei; Cui Yanfeng; Liu Hongtao; Wang Wenliang

    2012-01-01

    Objective: To evaluate the application of spiral-CT and 3D-imaging of airway for observation of efficacy and complication after tracheobronchial stent placement. Methods: Thirty-one patients treated with tracheal stents were retrospectively analyzed, of which there were 27 malignant tracheal stenosis, 2 benign tracheal stenosis, 1 bronchial remnant fistula and 1 gastroesophageal anastomosis tracheal fistula. The spiral-CT and 3D-imagings were analyzed and the location, shape and complication of the stents were assessed. Results: Thirty-one patients were treated with 8 Z-type stainless steel stents and 28 Ni-Ti memory alloy stents. The stents of 22 cases remained patent in the original position and restenosis was occurred in 5 cases, migration in 3 cases and fracture in 1 case. All the CT features were performed and reconstructed on the workstation, using multiplanar reconstruction, volume rendering, and CT virtual endoscopy. The location of tracheal stenosis and fistula were showed in different angle, and the location, shape of the stents, and the complications (such as restenosis, fracture) as well. Conclusion: Spiral-CT and 3D-imaging is a rapid, simple and effective method in assessing tracheal stent implantation and complication, therefore, it is of great value in clinical practice. (authors)

  6. Spiral hydro-CT of the pancreas in the thin-slice method; Hydrospiral-CT des Pankreas in Duennschichttechnik

    Energy Technology Data Exchange (ETDEWEB)

    Richter, G.M. [Abt. fuer Radiodiagnostik, Radiologische Universitaetsklinik Heidelberg (Germany); Simon, C. [Abt. fuer Radiodiagnostik, Radiologische Universitaetsklinik Heidelberg (Germany)]|[Abt. Allgemeine Chirurgie, Chirurgische Universitaetsklinik Heidelberg (Germany); Hoffmann, V. [Abt. fuer Radiodiagnostik, Radiologische Universitaetsklinik Heidelberg (Germany); DeBernardinis, M. [Abt. fuer Radiodiagnostik, Radiologische Universitaetsklinik Heidelberg (Germany); Seelos, R. [Abt. Allgemeine Chirurgie, Chirurgische Universitaetsklinik Heidelberg (Germany); Senninger, N. [Abt. Allgemeine Chirurgie, Chirurgische Universitaetsklinik Heidelberg (Germany); Kauffmann, G.W. [Abt. fuer Radiodiagnostik, Radiologische Universitaetsklinik Heidelberg (Germany)

    1996-05-01

    In an open prospective study, 151 patients with a suspected pancreatic neoplasm based on clinical, laboratory or other imaging data were examined between May 94 and October 95. Our newly developed Hydro-CT methodology included intravenous injection of 40 mg N-butylscopolaminium bromide (Buscopan) for intestinal paralysis, gastric and duodenal wall distension by oral administration of an average of 1.5 l warm tap water, 30 RAO patient positioning, an individualized contrast injection technique as determined beforehand by time-to-peak measurement in the portal vein and thin-slice spiral CT (3 mm increment, 6 mm table feed and 3 mm secondary reconstruction). A detailed evaluation form was used to assess (1) tumor detection rate, (2) differentiation of malignant versus benign disease, (3) differential diagnosis, and (4) accuracy of assessment of resectability by identification of infiltration into adjacent organs and vessel structures relevant for resectability such as splenic, superior mesenteric, portal vein and celiac trunk, superior mesenteric, splenic and hepatic arteries. As the gold standard for positive tumor detection surgery and microscopic diagnosis were used, and for negative tumor detection an event-free survival of 6 months. Almost all examinations were well tolerated. In only 4% was on-site administration of a gastric tube required because of vomiting. In 2% of the patients a slight allergic reaction to be contrast medium was seen. The prevalence of a pancreatic neoplasm was 38%. In tumor detection Hydro-CT reached an overall accuracy of 97.4% with a sensitivity of 100% and a specificity of 95.9%. In the differentiation of benign versus malignant disease Hydro-CT reached an overall accuracy of 89.7% with a sensitivity of 92.5% and a specificity of 83.3%. The prevalence of a pancreatic carcinoma was 24%; 4% other malignant tumors were found (distal common bile duct carcinoma, cystadenocarcinoma). (orig./MG) [Deutsch] Von Mai 1994 bis Oktober 1995 wurden

  7. Spiral CT arthrography of the knee: technique and value in the assessment of internal derangement of the knee

    Energy Technology Data Exchange (ETDEWEB)

    Berg, Vande B.C.; Lecouvet, F.E.; Maldague, B.; Malghem, J. [Department of Radiology, Cliniques Universitaires St. Luc, Universite Catholique de Louvain, Brussels (Belgium); Poilvache, P. [Department of Orthopedic Surgery, Cliniques Universitaires St. Luc, Universite Catholique de Louvain, Brussels (Belgium)

    2002-07-01

    Computed tomography imaging has achieved excellent multiplanar capability and submillimeter spatial resolution due to the development of the spiral acquisition mode and multidetector row technology. Multidetector spiral CT arthrography (CTA) yields valuable information for the assessment of internal derangement of the joints. This article focuses on the value of spiral CTA of the knee in the assessment of the meniscus, anterior cruciate ligament, and hyaline cartilage lesions. Advantages and disadvantages of spiral CTA with respect to MR imaging are presented. (orig.)

  8. Relationship of radiation dose and spiral pitch for multi-slice CT system

    International Nuclear Information System (INIS)

    Song Shaojuan; Wang Wei; Liu Chuanya

    2006-01-01

    Objective: To study the relations of radiation dose and spiral pitch for multi-slice CT system. Methods: 16 mm dose phantom with solidose 300/400 pen-style ion chamber inserted into each of five holes in turn was scanned with different spiral pitch by LightSpeed 16-slice CT and Sensation 16-slice and 64-slice CT and radiation dose. Results: CTDI vol of axial scan and spiral scan for the three types of CT system are: (1) LightSpeed 16-slice CT: 28.9 (axial), 51.4 (pitch 0.562), 30.8 (pitch 0.938) and 16.5 ( pitch 1.75 ); (2) Sensation 16-slice CT: 41.2(axial) and 40.3(pitch 0.5) ,41.5(pitch 1) and 43.2(pitch 1.5); (3) Sensation 64- slice CT: 41.2(axial) and 40.3(pitch 0.5),41.5(pitch 1),43.2(pitch 1.5). Conclusions: For LightSpeed 16-slice CT, the measured radiation dose decreased with the increase of spiral pitch, the image quality could keep constant only if we increase mAs. While for Sensation 16-slice and 64-slice CT system, the measured radiation dose was identical for different pitch, and the image quality was identical because of the use of mAs auto control technique The mAs should be adjusted in different way according to the type of CT system when the pitch is changed in daily operation. (authors)

  9. Multidetector spiral CT renal angiography in the diagnosis of renal artery fibromuscular dysplasia

    International Nuclear Information System (INIS)

    Sabharwal, Rohan; Vladica, Philip; Coleman, Patrick

    2007-01-01

    Objective: The aim of this study was to evaluate the role and detection rate of multidetector spiral CT renal angiography (CTA) as compared with conventional angiography (CA), the commonly accepted gold standard, in the diagnosis of renal artery fibromuscular dysplasia (FMD). In addition, the role of CTA reconstructions (multiplanar reformatted images (MPR), maximum intensity projections (MIP) and shaded-surface display (SSD)) in the detection of FMD was also evaluated. Materials and methods: CTA results were retrospectively reviewed in 21 hypertensive patients with CA-proven FMD. Clinical indications for referral included resistant hypertension (requiring greater than three antihypertensive medications), labile hypertension, hypertension in combination with renal impairment and the presence of abdominal bruits in the context of systemic hypertension. In some cases, these clinical indications were supplemented by positive results in other tests, including plasma renin assay, captopril scintigraphy and/or Doppler ultrasound. The findings of CA in these 21 patients were compared to CTA. Results: Mean patient age was 62.33 + 14.32 years (range 24-85 years). CTA identified all 42 main renal arteries (100%) and all 10 accessory renal arteries (100%) visualized on CA. In the diagnosis of FMD, CTA detected all 40 (100%) lesions detected by CA. No single CTA reconstruction technique was able to detect all lesions noted on corresponding CA, however, upon review of all CTA reconstructions (MPR, MIP and SSD) in each case, every lesion was correctly identified by CTA. Conclusion: Our experience suggests that CTA is a non-invasive, reliable and accurate method for the diagnosis of renal artery fibromuscular dysplasia. Moreover, in our experience CTA has many advantages as a diagnostic screening tool over CA, including accessibility, speed, lower complication profile, versatility and cost-effectiveness. CTA shows great potential as a guiding tool for directing subsequent

  10. Accelerated Compressed Sensing Based CT Image Reconstruction.

    Science.gov (United States)

    Hashemi, SayedMasoud; Beheshti, Soosan; Gill, Patrick R; Paul, Narinder S; Cobbold, Richard S C

    2015-01-01

    In X-ray computed tomography (CT) an important objective is to reduce the radiation dose without significantly degrading the image quality. Compressed sensing (CS) enables the radiation dose to be reduced by producing diagnostic images from a limited number of projections. However, conventional CS-based algorithms are computationally intensive and time-consuming. We propose a new algorithm that accelerates the CS-based reconstruction by using a fast pseudopolar Fourier based Radon transform and rebinning the diverging fan beams to parallel beams. The reconstruction process is analyzed using a maximum-a-posterior approach, which is transformed into a weighted CS problem. The weights involved in the proposed model are calculated based on the statistical characteristics of the reconstruction process, which is formulated in terms of the measurement noise and rebinning interpolation error. Therefore, the proposed method not only accelerates the reconstruction, but also removes the rebinning and interpolation errors. Simulation results are shown for phantoms and a patient. For example, a 512 × 512 Shepp-Logan phantom when reconstructed from 128 rebinned projections using a conventional CS method had 10% error, whereas with the proposed method the reconstruction error was less than 1%. Moreover, computation times of less than 30 sec were obtained using a standard desktop computer without numerical optimization.

  11. Accelerated Compressed Sensing Based CT Image Reconstruction

    Directory of Open Access Journals (Sweden)

    SayedMasoud Hashemi

    2015-01-01

    Full Text Available In X-ray computed tomography (CT an important objective is to reduce the radiation dose without significantly degrading the image quality. Compressed sensing (CS enables the radiation dose to be reduced by producing diagnostic images from a limited number of projections. However, conventional CS-based algorithms are computationally intensive and time-consuming. We propose a new algorithm that accelerates the CS-based reconstruction by using a fast pseudopolar Fourier based Radon transform and rebinning the diverging fan beams to parallel beams. The reconstruction process is analyzed using a maximum-a-posterior approach, which is transformed into a weighted CS problem. The weights involved in the proposed model are calculated based on the statistical characteristics of the reconstruction process, which is formulated in terms of the measurement noise and rebinning interpolation error. Therefore, the proposed method not only accelerates the reconstruction, but also removes the rebinning and interpolation errors. Simulation results are shown for phantoms and a patient. For example, a 512 × 512 Shepp-Logan phantom when reconstructed from 128 rebinned projections using a conventional CS method had 10% error, whereas with the proposed method the reconstruction error was less than 1%. Moreover, computation times of less than 30 sec were obtained using a standard desktop computer without numerical optimization.

  12. Clinical value of 64-slice spiral CT for classification of femoral neck fracture

    International Nuclear Information System (INIS)

    Zhu Jiangtao; Gong Jianping; Cai Wu; Zhu Jianbing; Chen Guangqiang; Qian Minghui

    2011-01-01

    Objective: To evaluate the clinical application of 64-slice spiral CT for classification of femoral neck fracture. Methods: The survey was comprised of 46 patients with femoral neck fractures detected with plain radiographs and CT images. Cases were randomly presented in 2 formats: plain radiographs and CT. Garden classification was queried. Modification of garden classification (nondisplaced vs displaced) was taken to compare with plain radiographs and CT in the study. Results: The results of classification for plain radiographs were 2 cases of Garden Ⅰ, 10 cases of Ⅱ, 22 cases of Ⅲ, and 12 cases of Ⅳ. Those for CT were 1 cases of Garden Ⅰ, 4 cases of Ⅱ, 26 cases of Ⅲ, and 15 cases of Ⅳ. CT improved the accuracy of Garden Classification (P<0.05). Conclusion: Garden classification using CT images shows good conformation with results of surgery. 64-Slic CT is better plain radiographs for Garden classification of femoral neck fracture. (authors)

  13. Classification of fractures of the distal r[ius - Comparative evaluation of spiral CT images and X-rays

    International Nuclear Information System (INIS)

    Roehnert, W.; Nitzsche, H.; Franck, W.M.; Amlang, M.

    1998-01-01

    Within the framework of a prospective study 35 patients with fractures of the distal r[ius safely diagnosed to require surgery have been [ditionally scanned by spiral CT. For more exact diagnostic evaluation of the joint surfaces and the fractures, multiplane reconstructions have been m[e to enhance the information obtained from the primary, axial tomographic images. Two experts independently performed classification on the basis of the X-rays and the CT scans, applying the AO scheme and the method of Frykman. Classifications according to the AO scheme were found to agree for only 28.6 % of the patients, which means that 57.1 % of the fractures shown by the X-rays were more or less underassessed. Classification according to Frykman's method revealed fewer deviations and agreement in 51.4 % of the cases. Biplanar r[iography continues to be considered as the standard method for examination of distal r[ius fractures, but it is recommended to perform spiral CT scans for evaluation of more complex distal r[ius fractures because these may require different therapies according to fracture types. (orig./CB) [de

  14. Assessment of value of spiral CT in preoperative evaluation of endovascular graft exclusion for abdominal aortic aneurysm

    International Nuclear Information System (INIS)

    Jing Zaiping; Zhao Jun; Zhu Wenjiang; Xiao Yi

    1998-01-01

    Purpose: The assess the value of spiral CT (SCT) in preoperative evaluation of endovascular graft exclusion (EVGE) for abdominal aortic aneurysm (AAA). Methods: 41 case with AAA received SCT scanning. Two and three dimensional images were reconstructed, utilizing the shaded surface display (SSD), maximum-intensity Projection (MIP) and multiplanar reformation (MPR). Information were obtained regarding the size and features of AAA, length and diameters of aneurysm's neck, status of the branches of aorta, etc. Results: Nine patients had spinal CT study prior EVGE procedure and the grafts selected according to the parameters obtained by SCT matched perfectly to the needs of deployment. Conclusion: CTA provides high quality images. It is a high-speed and non-invasive method which can provide three-dimensional images of AAA and its main branches and all the parameters needed in EVGE

  15. Image reconstruction design of industrial CT instrument for teaching

    International Nuclear Information System (INIS)

    Zou Yongning; Cai Yufang

    2009-01-01

    Industrial CT instrument for teaching is applied to teaching and study in field of physics and radiology major, image reconstruction is an important part of software on CT instrument. The paper expatiate on CT physical theory and first generation CT reconstruction algorithm, describe scan process of industrial CT instrument for teaching; analyze image artifact as result of displacement of rotation center, implement method of center displacement correcting, design and complete image reconstruction software, application shows that reconstructed image is very clear and qualitatively high. (authors)

  16. Detection of hepatocellular carcinoma with multi-slice spiral CT by ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-06-07

    Jun 7, 2010 ... The purpose of the study is to evaluate the effect of iodine concentration of contrast material on detection of hepatocellular carcinoma with multi-slice spiral computed tomography (CT) by using double-arterial phase and portal venous phase enhanced scanning. Ninety-four (94) patients with hepatocellular ...

  17. CT Imaging of facial trauma. The role of different types of reconstruction. Part II - soft tissues

    International Nuclear Information System (INIS)

    Myga-Porosilo, J.; Sraga, W.; Borowiak, H.; Jackowska, Z.; Kluczewska, E.; Skrzelewski, S.

    2011-01-01

    Background: Injury to facial soft tissues as a complication of skeleton fractures is an important problem among patients with facial trauma. The aim of this work was to assess the value of multiplanar and three-dimensional (3D) reconstruction computed tomography (CT) images obtained by using multi-detector row technology in spiral data acquisition in patients with facial injuries of soft tissue. Material/Methods: Sixty-seven patients diagnosed with injury to the facial skeleton underwent a CT scan with the use of GE Hispeed Qx/i scanner. For each patient: a two-dimensional (2D) multiplanar reconstruction (MPR), maximum intensity projection (MIP), and 3D volume rendering (VR) were conducted. Post-injury lesions of soft tissues were assessed. During the assessment of the post-injury lesions of soft tissues, the following features were evaluated: Extra ocular muscle and fat tissue herniation through fractures in the medial and inferior orbital walls. Fluid in the sinuses and in the nasal cavity. Subcutaneous tissue emphysema. Results: For subcutaneous emphysema and sinus fluid imaging, both the axial and the 2D image reconstruction proved comparably effective. However, 2D reconstructions were superior to transverse plane images with regard to herniations into fractures of the inferior orbital wall. 3D reconstruction has no importance in diagnosing soft tissue injuries. Conclusions: Multiplanar CT reconstructions increase the effectiveness of imaging of orbital tissue herniations, especially in case of fractures in the inferior orbital wall. In suspected soft tissue herniations, as well as prior to surgical treatment, spiral CT with 2D multiplanar reconstructions should be the method of choice. (authors)

  18. Prevalence of ligamentum arteriosum calcification on multi-section spiral CT and digital radiography.

    Science.gov (United States)

    Hong, Gil-Sun; Goo, Hyun Woo; Song, Jae-Woo

    2012-06-01

    To investigate the prevalence of ligamentum arteriosum calcification (LAC) on multi-section spiral CT and digital radiography. Five hundred and eight children and 232 adults who performed multi-section chest CT were included in this study and were divided into nine age groups: A (0-5 years), B (6-10 years), C (11-15 years), D (16-20 years), E (21-30 years), F (31-40 years), G (41-50 years), H (51-60 years), and I (61-70 years). Two radiologists assessed the presence of LAC on axial and coronal CT images, defined as focal calcific density on both or on one plane with attenuation >100 Hounsfield unit. The prevalence of LAC on CT was compared between children and adults, and between unenhanced and enhanced CT in children. The prevalence of LAC on digital radiography was evaluated in 476 children. The prevalence of definite LAC on unenhanced multi-section CT was significantly higher in children (37.8 %) than in adults (11.2 %) (P CT were 4.5, 12.8, 8.1, 19.0, 0.0, 0.0, 0.0, 2.0, and 1.9 %. In children, the prevalence of LAC was significantly higher on unenhanced than on enhanced CT (37.8 vs. 16.4 %, P children. LAC is frequently observed in children and adults on multi-section spiral CT, more frequently than previously reported. Compared with that on multi-section spiral CT, the prevalence of LAC on digital radiography is substantially low.

  19. Comparative analysis of multi-slice spiral CT and positron emission tomography-CT in evaluation of axillary lymph nodes in breast cancer patients

    International Nuclear Information System (INIS)

    Sun Xianchang; Zhang Ruyi; Liu Qingwei; Zhao Suhong; Zu Degui; Li Xin

    2008-01-01

    Objective: To evaluate and compare spiral CT and positron emission tomography-CT (PET-CT) in characterization of of axillary lymph nodes in breast cancer patients. Methods: Forty patients with pathologically proven breast cancer underwent contrast-enhanced spiral CT of the breast and axilla, 13 of them also underwent PET-CT examination. One hundred and fifty-eight axillary lymph nodes were found in the 40 patients through contrast enhanced spiral CT, while 57 lymph nodes were found in the 13 patients through PET-CT. Three radiologists rated the lymph nodes found in CT images on a five-point scale. If the score was equal to or greater than 3, it was defined as positive (metastatic), otherwise negative. Visual observation and semiquantitative analysis were used to classify lymph nodes in PET-CT images. The results of spiral CT observation and PET-CT observation of lymph nodes were compared with pathological results. The relative value of CT and PET-CT was analyzed. Exact probability statistics were employed. Results: One hundred and fifty eight lymph nodes of 40 patients were detected by spiral CT, 91 of them were diagnosed as positive and 67 as negative Among the lymph nodes found in spiral CT, 99 were positive and 59 were negative pathologicall. A total of 57 lymph nodes were found by PET-CT. Thirty-nine of them were defined as positive and 18 as negative. Among the lymph nodes found in PET-CT, 39 were positive and 18 were negative pathologically. The sensitivity, specificity, accuracy, positive and negative predictive values in CT prediction in axillary lymph nodes metastases were 88.89%, 94.91%, 91.14%, 96.70%, and 83.58%, respectively. The sensitivity, specificity, accuracy, positive and negative predictive values in PET-CT prediction in axillary lymph nodes metastases were 97.44%, 94.44%, 96.49%, 97.44%, and 94.44%, respectively. PET-CT had no significant difference with spiral CT in sensitivity, accuracy, positive and negative predictive values for detection

  20. Non-Cartesian Parallel Imaging Reconstruction of Undersampled IDEAL Spiral 13C CSI Data

    DEFF Research Database (Denmark)

    Hansen, Rie Beck; Hanson, Lars G.; Ardenkjær-Larsen, Jan Henrik

    scan times based on spatial information inherent to each coil element. In this work, we explored the combination of non-cartesian parallel imaging reconstruction and spatially undersampled IDEAL spiral CSI1 acquisition for efficient encoding of multiple chemical shifts within a large FOV with high...

  1. TRIPLE PHASE SPIRAL C.T. IN THE EVALUATION OF HEPATIC MASSES

    Directory of Open Access Journals (Sweden)

    Prasad

    2015-10-01

    Full Text Available BACKGROUND AND OBJECTIVE : The goal of the study is to determine the value of various phases of Triple, Helical CT, Hepatic arterial Phase (HAP, Portal venous phase (PVP and Equilibrium Phase (EP, is the detection and characterization of Hepatic Lesions and to evaluate whether u nenhanced and hepatic arterial phases when used in conjunction with porto venous phase would lead to detection of greater number of lesions or better characterization of lesion. METHODOLOGY : The study population consists of 50 Patients aged between 30 Years and 80 Years were examined with multiphase (plain, hepatic arterial, portal venous and equilibrium phases. Spiral CT of liver. Patients were referred for CT scan when liver diseases were suspected clinically, if ultrasound and other previous investi gations revealed lesions which had to be further evaluated by spiral CT and to detect liver metastases in known cases of primary extra hepatic malignancy. CT TECHNIQUE: Helical scanning of liver with Toshiba astein s4, continuous spiral run and the images were reconstructed at 5mm intervals. Contrast material 100ml was injected through 18 or 20G catheter at the rate of 3ml per second using automatic medrad power injector. Non - ionic contrast [IOHEXOl – 300mg perml was used in all the patients]. After obtaine d unenhanced CT scan HAP scanning was initiated 25 seconds after initiation of contrast injection. Portal venous phase scanning was initiated 60 - 65 seconds after start of contrast injection. Equilibrium phase scanning was initiated after 180 seconds after the start of contrast injection. IMAGE EVALUATION: All the images of 4 phases were reviewed. First Step : The presence, appearance and enhancement of each Lesion were noted in all phases and lesion were described Isodense, Hypodense Hyperdense based on thei r attenuation relative to liver parenchyma during that phase of scanning. Based on enhancement pattern of the lesion during various phases they were

  2. Application of triple rule-out with 64-slice spiral CT in the diagnosis of acute chest pain

    International Nuclear Information System (INIS)

    Li Pengyu; Li Kuncheng; Du Xiangyin; Cao Lizhen; Liu Jiabin; Yang Yanhuui; Liang Zhigang; Zhu Xiaolian; Liu Jian

    2007-01-01

    Objective: To investigate the performance of triple rule-out with 64-slice spiral CT in the combined examination of pulmonary artery, thoracic aorta and coronary artery for patients with acute chest pain. Methods: Seventy patients who presented with acute chest pain were included in the study. All of the patients underwent retrospective ECG-gated 64-slice computed tomography triple rule-out examination to evaluate the pulmonary arteries, thoracic aorta and coronary arteries. Multi-planar reconstruction (MPR), maximum intensity projection (MIP), curved-planar reconstruction (CPR) and volume rendering (VR) were used to display pulmonary arteries, thoracic aorta and coronary arteries. We evaluated the image quality of coronary artery and the enhancement of the pulmonary artery and thoracic aorta to estimate if the examination can fulfill the clinical demand for the differential diagnosis of acute chest pain. Results: The mean scan time was (8.5±1.0) s, and the dose of contrast medium injected was 100 ml. There were 95.7% (67/70) of patients whose CT values detected in the pulmonary artery and thoracic aorta after enhancement Were ≥200 HU. The image quality of 85.8% (720/839) coronary segments was classified as excellent, 8.6% (72/839) as good, and 5.6% (47/839) as poor. There were 20 eases with coronary stenoses ≥50%, 2 cases with pulmonary embolism, and 2 cases with aortic dissection. Conclusion: The triple rule-out examination with 64-slice spiral CT could depict pulmonary artery, thoracic aorta, and coronary artery in 8 s with good image quality. It has great potential in the etiological diagnosis for the patients with acute chest pain. (authors)

  3. Superiority of CT imaging reconstruction on Linux OS

    International Nuclear Information System (INIS)

    Lin Shaochun; Yan Xufeng; Wu Tengfang; Luo Xiaomei; Cai Huasong

    2010-01-01

    Objective: To compare the speed of CT reconstruction using the Linux and Windows OS. Methods: Shepp-Logan head phantom in different pixel size was projected to obtain the sinogram by using the inverse Fourier transformation, filtered back projection and Radon transformation on both Linux and Windows OS. Results: CT image reconstruction using the Linux operating system was significantly better and more efficient than Windows. Conclusion: CT image reconstruction using the Linux operating system is more efficient. (authors)

  4. Enhanced dual-phase spiral CT features of polypoid ampullary carcinoma

    International Nuclear Information System (INIS)

    Zeng Mengsu; Yan Fuhua; Zhou Kangrong; Chen Huiming; Chen Gang; Chen Jin

    2001-01-01

    Objective: To understand CT features of polypoid ampullary carcinoma by enhanced dual-phase spiral CT. Methods: 15 cases of polypoid ampullary carcinoma (PAC) confirmed by surgical and pathological results were studied with thin slice enhanced dual-phase spiral CT (including arterial and portal phase scanning)with retrospective analysis, the scanning parameters were 5 mm thickness and 1.0 pitch for arterial phase scanning, and 5 mm thickness and 5 mm space for portal phase scanning. Results: All cases could display an enhanced mass as local filling defect at the site of the duodenal Vater's ampulla during arterial and portal phase scanning, the tumors ranged in size from 1 cm to 5 cm with mean of 2.3 cm, all were accompanied with dilated intrahepatic and common bile duct, enlarged gallbladder and dilated pancreatic duct, except one case which had marked atrophy of the pancreatic body and tail. Conclusion: The thin slices enhanced dual-phase spiral CT could not only accurately define the level of obstruction, but also demonstrate an enhanced mass as direct CT sign of the PAC, which is crucial for diagnosis of the PAC

  5. CT and MRI post-processing reconstructions in maxillo-facial trauma

    International Nuclear Information System (INIS)

    Olszycki, M.; Grzelak, P.; Stanczyk, L.; Kozakiewicz, M.; Arkuszewski, P.

    2004-01-01

    The aim of the study is to evaluate the reliability of CT and MR imaging and their post-processing reconstructions in the cases of facial trauma. CT studies were performed in 34 patients: 13 suspected of sinus fractures, 20 with orbital fractures and 1 with broken supraorbital bone fragment. MR imaging was also performed in 16 of these patients. The CT data were reconstructed in the 2D and 3D mode. The CT and MR images were digitally fused using an own program. The CT and MR images, their reconstructions and their fusion were evaluated according to the quality of visualization of a pathological lesions. Surgery was the method of reference. The reconstructed CT images allowed to recognize properly maxillary-oral fenestration in 5 cases. In 20 patients with orbital fracture, CT 3D reformations visualized well the morphology of the fissure. In 13 of these patients,the small bone fragments and orbital soft tissues prolapsed towards the maxillary sinus were depicted. Among the 16 patients who underwent MR examination, in 6 cases we revealed dislocation of the inferior rectus muscle towards the sinus, whereas in 9 cases MR images clearly excluded this pathology. In 1 patient, the digitally fused CT/MR images allowed to determine the actual position of small bone fragment within the muscle. In 1 patient with broken supraorbital bone fragment, evaluation of the 3D model allowed to exclude communication with intracranial space. In the next 8 patients with maxillo-zygomatic injures, the CT reconstructions did not support the diagnosis. The surgery correlated well with the post-processing CT and CT/MR fused images, contrary to the original CT ones which often were diagnostically insufficient. Spiral CT 2D and 3D-reconstructed images of the face allow to depict clearly the anatomical spatial relationships and the position, course and displacement of fractured fragments; thus, they support the surgery. The MR images of these patients reveal soft tissues clearly. The digital

  6. Spiral CT during pharmacoangiography with angiotensin II in patients with pancreatic disease. Technique and diagnostic efficacy

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, C.; Mihara, N.; Hosomi, N.; Inoue, E.; Fujita, M. [Osaka Medical Center for Cancer and Cardiovascular Diseases (Japan). Dept. of Diagnostic Radiology; Ohigashi, H.; Ishikawa, O. [Osaka Medical Center for Cancer and Cardiovascular Diseases (Japan). Dept. of Surgery; Nakaizumi, A. [Osaka Medical Center for Cancer and Cardiovascular Deseases (Japan). Dept. of Internal Medicine; Ishiguro, S. [Osaka Medical Center for Cancer and Cardiovascular Diseases (Japan). Dept. of Pathology

    1998-03-01

    Purpose: To compare the diagnostic efficacy of pancreatic pharmacoangiographic CT using angiotensin II with conventional angiographic CT. Material and Methods: Eighteen patients with space-occupying pancreatic disease were examined in this study. Pharmacoangiographic CT was performed with a 1-3-{mu}/6-ml solution of angiotensin II injected through a catheter into the celiac artery during spiral CT. Results: In 17 of the 18 (94%) patients, the area of pancreatic parenchymal enhancement was the same or larger at pharmacoangiographic CT than at conventional angiographic CT. The attenuation value of the pancreatic parenchyma was significantly increased at pharmacoangiographic CT (p=0.0010). Although the attenuation value of tumors was also increased on images obtained after the injection of angiotensin II, the tumor-to-pancreas contrast was significantly greater at pharmacoangiographic CT (p=0.0479). The mean differences in attenuation between tumor and pancreas at angiographic CT with and without angiotensin II were respectively 182 HU and 115 HU. Conclusion: Pharmacoangiographic CT with angiotensin II proved superior to conventional angiographic CT in the diagnosis of pancreatic disease. We therefore recommend it as a supplementary technique at the angiographic examination of patients with suspected pancreatic tumor. (orig.).

  7. Spiral CT features and anatomic basis of posterior pararenal space involvement in acute pancreatitis

    International Nuclear Information System (INIS)

    Min Pengqiu; Yan Zhihan; Yang Hengxuan; Liu Zaiyi; Song Bin; Wu Bing; Zhang Jin; Liu Rongbo

    2005-01-01

    Objective: To evaluate spiral CT features and anatomic basis of the posterior pararenal space (PPS) involvement in acute pancreatitis (AP). Methods: CT images of 87 cases with AP were retrospectively studied with focus on spiral CT features, incidence of the PPS involvement, and its correlations with the posterior renal fascia or lateroconal fascia. Results: Our study showed that the incidence of the PPS involvement was 47% (41/87), with Grade A 53% (46/87), Grade B 24%(21/87), and Grade C 23% (20/87), and Grade 0 53% (46/87), Grade I 22% (19/87), and Grade II 25% (22/87), respectively. The pancreatitis fluid collection in the PPS was continuous with that in the anterior pararenal space or with the fluid between the two laminae of the posterior renal fascia. In 3 follow-up cases, pseudocysts in the PPS were continuous with that in anterior pararenal space below the cone of renal fascia. Conclusion: Spiral CT features of the PPS involvement varies from mild inflammatory changes to fluid collection or phlegmonous mass. Fluid within anterior pararenal space in AP flows into the PPS by three routes. (authors)

  8. Evaluation of 16 detector row spiral CT in diagnosing pulmonary embolism

    International Nuclear Information System (INIS)

    Yu Xiaokun; Li Lei

    2008-01-01

    Objective: To investigate the value of 16 detector row spiral CT in the diagnosis of pulmonary embolism(PE). Methods: Imaging data of 20 patients (plain 16 detector row spiral CT scanning plus enhanced scanning imaging) highly suspected of PE was retrospectively analyzed. Results: Among the 20 cases, embolism was showed in 13 patients on 16 detector row spiral CT pulmonary angiography (MSCTPA). 6 cases of the 13 PE's patients have masculine findings on plain MSCT scanning images. Localized tenuous lung markings, dilated pulmonary artery, 'mosaic' sign, pleural or pericardial effusion, local high attenuation centrally in the pulmonary arteries and lung infarction occurred respectively. Conclusion: MSCTPA may be an effective, simple and safe technique for the diagnosis of PE. It was a reliable means in defecting PE However, for the cases unfit for contrast media and cases only suitable for unenhanced CT because of nonspecific heart-pulmonary symptom, noticeable abnormal signs of plain MSCT scanning could suggest the occurrence of pulmonary embolism. (authors)

  9. Establishment of an orthotopic lung cancer model in nude mice and its evaluation by spiral CT.

    Science.gov (United States)

    Liu, Xiang; Liu, Jun; Guan, Yubao; Li, Huiling; Huang, Liyan; Tang, Hailing; He, Jianxing

    2012-04-01

    To establish a simple and highly efficient orthotopic animal model of lung cancer cell line A549 and evaluate the growth pattern of intrathoracic tumors by spiral CT. A549 cells (5×10(6) mL(-1)) were suspended and inoculated into the right lung of BALB/c nude mice via intrathoracic injection. Nude mice were scanned three times each week by spiral CT after inoculation of lung cancer cell line A549. The survival time and body weight of nude mice as well as tumor invasion and metastasis were examined. Tissue was collected for subsequent histological assay after autopsia of mice. The tumor-forming rate of the orthotopic lung cancer model was 90%. The median survival time was 30.7 (range, 20-41) days. The incidence of tumor metastasis was 100%. The mean tumor diameter and the average CT value gradually increased in a time-dependent manner. The method of establishing the orthotopic lung cancer model through transplanting A549 cells into the lung of nude mice is simple and highly successful. Spiral CT can be used to evaluate intrathoracic tumor growth in nude mice vividly and dynamically.

  10. [Application of Low Dose Spiral CT in Diagnosing Impacted Teeth in Children and Adolescents].

    Science.gov (United States)

    Wang, Meng-tian; Li, Xue-sheng; Li, Kai-ming; Bao, Li; Ning, Gang

    2015-09-01

    [ABSTRACT] To determine the value of low dose spiral CT scanning in diagnosing impacted teeth of children and adolescents. A total of 153 children and adolescents with confirmed impacted teeth in West China Second University Hospital, Sichuan University were enrolled in this study. They were divided into 5 groups according to the different spiral CT scan parameters (tube current time product, scanning thickness and collimation value): Group A (n=30, 330 mAs, 6 X 0. 75 mm and 3. 0 mm), Group B (n=30, 140 mAs, 6 X 0. 75 mm and 3. 0 mm), Group C (n=30, 80 mAs, 6 X 0. 75 mm and 3. 0 mm), Group D (n=31, 80 mAs, 6 X 1. 50 mm and 5. 0 mm), and Group E (n=32, 50 mAs, 6 X 1. 50 mm and 5. 0 mm). There were no significant differences in general clinical features (P>0. 05) among the participants of the five groups. The phantoms were used to measure spatial resolution and contrast resolution of the scan images. Dose length product (DLP) was recorded during CT scanning for calculating effective dose (ED) of exposure. The quality of images was evaluated using a list of quality scoring criteria. (1) Under 330, 140, 80, 80 and 50 mAs, the images had a spatial resolution of 1.0 mm, with contrast resolution of 2. 0, 3. 0, 4. 5, 4. 5 and 6. 0 mm, respectively. (2) Significant differences in ED values were found among the five groups (F=1 064. 119, P=0. 000) and between every two of those groups (P0. 05). The diagnostic results of the spiral CT were consistent with those of orthodontic surgery. Low dose spiral CT scanning can meet the image quality requirements for diagnosing impacted teeth, minimizing radiation exposure effectively.

  11. Virtual endoscopy using spiral CT in patients with carcinomas of the hypopharynx and larynx

    International Nuclear Information System (INIS)

    Song, Sang Gook; Seo, Jeong Jin; Chung, Tae Woong; Kim, Hyeong Kil; Jeong, Gwang Woo; Jeong, Yong Yeon; Kang, Heoung Keun; Cho, Jae Sik

    2000-01-01

    To compare the usefulness of virtual endoscopy using spiral CT with that of laryngoscopy in the detection and evaluation of laryngeal and pharyngeal carcinomas. Twenty-four patients with pathologically proven laryngeal and pharyngeal carcinomas underwent laryngoscopy and virtual endoscopy using spiral CT. Eleven of the carcinomas were supraglottic, five were glottic, and eight were hypopharyngeal. Source images obtained by spiral CT were transmitted to an independent workstation and virtual endoscopic images were obtained using Navigator software. These were graded according to their quality (good, fair, bad), and were interpreted by two radiologists who were blinded to the conventional endoscopic findings. These latter were subsequently compared with the virtual endoscopic findings in terms of similarity to laryngoscopic examination and detectability of lesions. The overall image quality of virtual endoscopy was good in 16 cases (67%), fair in eight (33%), and bad in no case. Among the 11 supraglottic carcinomas, image quality was good in seven cases (64%), and fair in four (36%). In four of the five glottic carcinomas (80%) quality was good, and in one case (20%) it was fair, while among the eight hypopharyngeal carcinomas, quality was good in five cases (63%), and fair in three (37%). Overall, detection of the lesion was possible in 23 cases (96%). Due to the small size of the lesion, the one case of glottic carcinoma was not detected. Virtual endoscopy using spiral CT is a safe and noninvasive method, and also successfully detects laryngeal and pharyngeal lesions, with good image quality. For the evaluation of laryngeal and hypopharyngeal carcinoma, its use ma complement that of axial CT. (author)

  12. Efficacy of spiral CT in the evaluation of peritoneal seeding of gastric cancer

    International Nuclear Information System (INIS)

    Choi, Hyuck Jae; Han, Joon Koo; Kim, Tae Kyoung; Kim, Ah Young; Lee, Joon Woo; Moon, Min Hoan; Yang, Han Kwang; Choi, Byung Ihn

    2001-01-01

    To determine usefulness of spiral CT in the preoperative evaluation of peritoneal seeding from a gastric carcinoma. From a database of 411 consecutive patients with surgically proven advanced gastric cancinoma obtained over a six-month period, 17 with peritoneal seeding and a control group of 24 without peritoneal seeding underwent spiral CT scanning with 7-8 mm scan thickness and interval during the portal phase. Preoperative CT images were analyzed by two readers who reached a consensus with regard to the presence and location of the ascites, thickening of the parietal peritoneum, and changes in the omentum and mesentery. Ascites was present in 47% (8/17) of patients with peritoneal seeding the right subhepatic space (n=6, 35%) and right paracolic gutter (n=5, 29%)-but not the cul-de-sac (n=2, 12%)-were common sites of fluid collection. Permeative changes in the omentum and mesentery were seen in 18% (3/17) and 12% (2/17) of patients, respectively. Among five controls with false positive results, ascites in the cul-de-sac was present in three (two males and one female, 12%) while omental nodules and a thickened peritoneum were found in two (8%) and one (4%), respectively. In nine controls with false negative results, small disseminated nodules were seen in the mesentery and omentum at surgical field. The sensitivity and specificity of spiral CT were 47% (8/17) and 79% (19/24), respectively. In terms of sensitivity and specificity, spiral CT is not especially accurate in distinguishing peritoneal seeding from gastric carcinoma

  13. Applicability of 3D-CT facial reconstruction for forensic individual identification

    International Nuclear Information System (INIS)

    Rocha, Sara dos Santos; Ramos, Dalton Luiz de Paula; Cavalcanti, Marcelo de Gusmao Paraiso

    2003-01-01

    Computed tomography (CT) is used in several clinical dentistry applications even by axial slices and two and three-dimensional reconstructed images (2D-CT and 3D-CT). The purpose of the current study is to assess the precision of linear measurements made in 3D-CT using cranio metric patterns for individual identification in Forensic Dentistry. Five cadaver heads were submitted to a spiral computed tomography using axial slices, and 3D-CT reconstructions were obtained by volume rendering technique with computer graphics tools. Ten (10) cranio metric measurements were determined in 3D-CT images by two examiners independently, twice each, and the standard error of intra- and inter-examiner measurements was assessed. The results demonstrated a low standard error of those measurements, from 0.85% to 3.09%. In conclusion, the linear measurements obtained in osseous and soft tissue structures were considered to be precise in 3D-CT with high imaging quality and resolution. (author)

  14. Applicability of 3D-CT facial reconstruction for forensic individual identification

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Sara dos Santos [Sao Paulo Univ., SP (Brazil). Odontologia Forense; Ramos, Dalton Luiz de Paula [Sao Paulo Univ., SP (Brazil). Dept. of Odontologia Social; Cavalcanti, Marcelo de Gusmao Paraiso [Sao Paulo Univ., SP (Brazil). Dept. de Radiologia

    2003-03-01

    Computed tomography (CT) is used in several clinical dentistry applications even by axial slices and two and three-dimensional reconstructed images (2D-CT and 3D-CT). The purpose of the current study is to assess the precision of linear measurements made in 3D-CT using cranio metric patterns for individual identification in Forensic Dentistry. Five cadaver heads were submitted to a spiral computed tomography using axial slices, and 3D-CT reconstructions were obtained by volume rendering technique with computer graphics tools. Ten (10) cranio metric measurements were determined in 3D-CT images by two examiners independently, twice each, and the standard error of intra- and inter-examiner measurements was assessed. The results demonstrated a low standard error of those measurements, from 0.85% to 3.09%. In conclusion, the linear measurements obtained in osseous and soft tissue structures were considered to be precise in 3D-CT with high imaging quality and resolution. (author)

  15. Impact of iterative reconstruction on CT coronary calcium quantification

    DEFF Research Database (Denmark)

    Kurata, Akira; Dharampal, Anoeshka; Dedic, Admir

    2013-01-01

    We evaluated the influence of sinogram-affirmed iterative reconstruction (SAFIRE) on the coronary artery calcium (CAC) score by computed tomography (CT).......We evaluated the influence of sinogram-affirmed iterative reconstruction (SAFIRE) on the coronary artery calcium (CAC) score by computed tomography (CT)....

  16. SPECT/spiral-CT hybrid imaging in unclear foci of increased bone metabolism: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Roemer, W.; Kuwert, T. [Nuklearmedizinische Klinik, Friedrich-Alexander-Univ. Erlangen/Nuernberg (Germany); Beckmann, M.W. [Frauenklinik, Friedrich-Alexander-Univ. Erlangen/Nuernberg (Germany); Forst, R. [Lehrstuhl fuer Orthopaedie mit Orthopaedischer Chirurgie, Friedrich-Alexander Univ. Erlangen/Nuernberg (Germany); Bautz, W. [Radiologisches Inst., Friedrich-Alexander-Univ. Erlangen/Nuernberg (Germany)

    2005-07-01

    In bone scintigraphy, the differentiation between degenerative processes and bone metastases is still difficult. Therefore, additional radiological studies are regularly needed after bone scintigraphy. The now introduced hybrid-cameras combining single-photon emission computed tomography (SPECT) and spiral-CT are unique in the sense that they offer the opportunity to correlate the functional information with morphology in one session. We herein present two patients in whom this technological setup allowed a definite diagnosis in scintigraphically unclear vertebral lesions. In a patient with breast cancer, hypermetabolic lesions were clearly correlated with osteolyses. In another patient with synovial carcinoma, spondylosis and spondylarthrosis caused focal tracer uptake in the lumbar spine. In addition to an improved diagnostic accuracy, SPECT/Spiral-CT will considerably abbreviate the diagnostic process. (orig.)

  17. SPECT/spiral-CT hybrid imaging in unclear foci of increased bone metabolism: a case report

    International Nuclear Information System (INIS)

    Roemer, W.; Kuwert, T.; Beckmann, M.W.; Forst, R.; Bautz, W.

    2005-01-01

    In bone scintigraphy, the differentiation between degenerative processes and bone metastases is still difficult. Therefore, additional radiological studies are regularly needed after bone scintigraphy. The now introduced hybrid-cameras combining single-photon emission computed tomography (SPECT) and spiral-CT are unique in the sense that they offer the opportunity to correlate the functional information with morphology in one session. We herein present two patients in whom this technological setup allowed a definite diagnosis in scintigraphically unclear vertebral lesions. In a patient with breast cancer, hypermetabolic lesions were clearly correlated with osteolyses. In another patient with synovial carcinoma, spondylosis and spondylarthrosis caused focal tracer uptake in the lumbar spine. In addition to an improved diagnostic accuracy, SPECT/Spiral-CT will considerably abbreviate the diagnostic process. (orig.)

  18. Hepatic hemangioma: contrast enhancement patterns on two-phase spiral CT

    International Nuclear Information System (INIS)

    Yun, Eun Joo; Choi, Byung Ihn; Han, Joon Koo; Jang, Hyun Jung; Kim, Tae Kyoung; Kim, Ah Young; Lee, Ki Yeol

    1998-01-01

    To evaluate contrast enhancement patterns of hemangioma according to size, as seen during the arterial and portal venous phase of spiral CT. Overall, the most common enhancement pattern was peripheral high (44/82, 53.7%), during the arterial and portal venous phase. The second and third most common patterns were uniform high (11/82, 13.4%) and peripheral high-uniform high (9/82, 11.0%), also during the arterial and portal venous phase. In tumors smaller than 20 mm, low-low attenuation was seen in eight (9.8%), and iso-low attenuation in two (2.4%), during the arterial and portal venous phase, respectively. On two-phase spiral CT, the most common enhancement pattern of hemangioma was peripheral high, seen during the arterial and portal venous phase. However, a small hemangioma less than 2cm may show atypical patterns, including low and iso attenuation. (author). 23 refs., 1 tab., 4 figs

  19. The potentials of spiral CT for detection of focal liver lesions

    International Nuclear Information System (INIS)

    Helmberger, H.; Kersting-Sommerhoff, B.; Lenz, M.; Kirsten, R.; Bautz, W.

    1996-01-01

    Spiral CT currently is the modality of choice for all aspects of diagnostic evaluation of the liver. Optimal selection of treatment should be based inter alia on the findings obtained by spiral CT with arterial application of contrast medium, as for example S-CTA (primary liver tumors), or S-CTAP (secondary liver tumors). Ultrasonography is the major supplementing modality. In the near future, MR imaging applying liver-specific contrast-enhancing agents is expected to become an important competing technique, and further developments of interest in diagnostic imaging of the liver are in the offing: it is not yet known which technique will be the modality of choice at the onset of the 21st century. (orig.) [de

  20. Respiration-correlated spiral CT: A method of measuring respiratory-induced anatomic motion for radiation treatment planning

    International Nuclear Information System (INIS)

    Ford, E.C.; Mageras, G.S.; Yorke, E.; Ling, C.C.

    2003-01-01

    We describe a method for generating CT images at multiple respiratory phases with a single spiral CT scan, referred to as respiratory-correlated spiral CT (RCCT). RCCT relies on a respiration wave form supplied by an external patient monitor. During acquisition this wave form is recorded along with the initiation time of the CT scan, so as to 'time stamp' each reconstructed slice with the phase of the respiratory cycle. By selecting the appropriate slices, a full CT image set is generated at several phases, typically 7-11 per cycle. The CT parameters are chosen to optimize the temporal resolution while minimizing the spatial gap between slices at successive respiratory cycles. Using a pitch of 0.5, a gantry rotation period of 1.5 s, and a 180 degree sign reconstruction algorithm results in ∼5 mm slice spacing at a given phase for typical respiration periods, and a respiratory motion within each slice that is acceptably small, particularly near end expiration or end inspiration where gated radiotherapy is to occur. We have performed validation measurements on a phantom with a moving sphere designed to simulate respiration-induced tumor motion. RCCT scans of the phantom at respiratory periods of 4, 5, and 6 s show good agreement of the sphere's motion with that observed under fluoroscopic imaging. The positional deviations in the sphere's centroid between RCCT and fluoroscopy are 1.1±0.9 mm in the transaxial direction (average over all scans at all phases ±1 s.d.) and 1.2±1.0 mm in the longitudinal direction. Reconstructed volumes match those expected on the basis of stationary-phantom scans to within 5% in all cases. The surface distortions of the reconstructed sphere, as quantified by deviations from a mathematical reference sphere, are similar to those from a stationary phantom scan and are correlated with the speed of the phantom. A RCCT scan of the phantom undergoing irregular motion, demonstrates that successful reconstruction can be achieved even with

  1. Wedge-shaped parenchymal enhancement peripheral to the hepatic hemangioma : two-phase spiral CT findings

    International Nuclear Information System (INIS)

    Kim, Kyoung Won; Kim, Tae Kyoung; Han, Joon Koo; Kim, Ah Young; Lee, Hyun Ju; Song, Chi Sung; Choi, Byung Ihn

    2000-01-01

    To determine the incidence of hepatic hemangiomas associated with wedge-shaped parenchymal enhancements adjacent to the tumors as seen on two-phase spiral CT images obtained during the hepatic arterial phase and to characterize the two-phase spiral CT findings of those hemangiomas. One hundred and eight consecutive hepatic hemangiomas in 63 patients who underwent two-phase spiral CT scanning during an 11-month period were included in this study. Two-phase spiral CT scans were obtained during the hepatic arterial phase (30-second delay) and portal venous phase (65-second delay) after injection of 120 mL of contrast material at a rate of 3 mL/sec. We evaluated the frequency with which wedge-shaped parenchymal enhancement was adjacent to the hemangiomas during the hepatic arterial phase and divided hemangiomas into two groups according to whether or not wedge-shaped parenchymal enhancement was noted (Group A and Group B). The presence of such enhancement in hemangiomas was correlated with tumor size and the grade of intratumoral enhancement. In 24 of 108 hemangiomas, wedge-shaped parenchymal enhancement adjacent to hepatic tumors was seen on two-phase CT images obtained during the hepatic arterial phase. Mean hemangioma size was 22mm in group A and 24mm in group B. There was no statistically significant relationship between lesion size and the presence of wedge-shaped parenchymal enhancement adjacent to a hemangioma. In 91.7% and 100% of tumors in Group A, and in 9.6% and 17.8% in Group B, hemangiomas showed more than 50% intratumoral enhancement during the arterial and portal venous phase, respectively. Wedge-shaped parenchymal enhancements peripheral to hepatic hemangiomas was more frequently found in tumors showing more than 50% intratumoral enhancement during these two phases (p less than 0.01). Wedge-shaped parenchymal enhancements is not uncommonly seen adjacent to hepatic hemangiomas on two-phase spiral CT images obtained during the hepatic arterial phase. A

  2. Functioning islet cell tumor of the pancreas. Localization with dynamic spiral CT

    International Nuclear Information System (INIS)

    Chung, M.J.; Choi, B.I.; Han, J.K.; Chung, J.W.; Han, M.C.; Bae, S.H.

    1997-01-01

    Purpose: The purpose of this study was to evaluate the usefulness of dynamic spiral CT, including multidimensional reformation, in the detection and localization of islet cell tumors of the pancreas. Material and Methods: Seven patients with histopathologically proven functioning islet cell tumors of the pancreas were studied with 2-phase contrast-enhanced spiral CT. Scanning of the arterial phase and late phase was started 30 s and 180 s, respectively, after injection of 100 ml of contrast medium at a rate of 3 ml/s. Results: Axial images in the arterial phase depicted the lesions in 5 patients, but in the late phase in only one patient. Multiplanar reformatted images of the arterial phase depicted the lesions in all 7 patients. Maximal intensity projection images demonstrated all lesions with information of their relationship to the vascular structure. Conclusion: Dynamic spiral CT with scanning during the arterial phase and retrospective multidimensional reformation is useful for preoperative detection and localization of small islet cell tumors of the pancreas. (orig.)

  3. Spiral CT in kidney: assumption of renal function by objective evaluation of renal cortical enhancement

    International Nuclear Information System (INIS)

    Choi, Bo Yoon; Lee, Jong Seok; Lee, Joon Woo; Myung, Jae Sung; Sim, Jung Suk; Seong, Chang Kyu; Kim, Seung Hyup; Choi, Guk Myeong; Chi, Seong Whi

    2000-01-01

    To correlate the degree of renal cortical enhancement, objectively evaluated by means of spiral CT with the serum level of creatinine, and to determine the extent to which this degree of enhancement may be used to detect renal parenchymal disease. Eighty patients (M:F = 50:30; age + 25-19, (mean 53) years) with available serum level of creatinine who underwent spiral CT between September and October 1999 were included in this study. In fifty patients the findings suggested hepatic or biliary diseases such as hepatoma, biliary cancer, or stone, while in thirty, renal diseases such as cyst, hematoma, or stone appeared to be present. Spiral CT imaging of the cortical phase was obtained at 30-40 seconds after the injection of 120 ml of non-ionic media at a rate of 3 ml/sec. The degree of renal cortical enhancement was calculated by dividing the CT attenuation number of renal cortex at the level of the renal hilum by the CT attenuation number of aorta at the same level. The degree of renal cortical enhancement was compared with the serum level of creatinine, and the degree of renal cortical enhancement in renal parenchymal disease with that of the normal group. Among eighty patients there were five with renal parenchymal disease and 75 with normal renal function. The ratio of the CT attenuation number of renal cortex to that of aorta at the level of the renal hilum ranged between 0.49 and 0.99 (mean, 0.79; standard deviation, 0.15). while the serum level of creatinine ranged between 0.6 and 3.2 mg/dl. There was significant correlation (coefficient of -0.346) and a statistically significant probability of 0.002 between the ratio of the CT attenuation numbers and the serum level of creatinine. There was a significant difference (statistically significant probability of less than 0.01) between those with renal parenchymal disease and the normal group. The use of spiral CT to measure the degree of renal cortical enhancement provides not only an effective index for

  4. Power doppler ultrasound findings of renal infarct after experimental renal artery occlusion: comparison with spiral CT

    International Nuclear Information System (INIS)

    Jung, Seung Eun; Shinn, Kyung Sub; Kim, Hak Hee; Mun, Seok Hwan; Lee, Young Joon; Lee, Bae Young; Choi, Byung Gil; Lee, Jae Mun; Lee, Hee Jeong

    1999-01-01

    To evaluate the efficacy of power Doppler ultrasonography (PDUS) in depicting renal infarction in rabbits during experimental renal segmental arterial occlusion, and to compare the results with those of CT scanning. In 28 rabbits weighing 2.5 4kg, the segmental renal artery was occluded through the left main renal artery by embolization with Ivalon (Nycomed, Paris, France). Power Doppler ultrasonography and spiral CT scanning were performed before and at 2, 5, 8, 15, and 24 hours, and 3 and 7 days after occlusion of the segmental renal artery. The location of infarcted areas and collaterals, as seen on PDUS and CT scans, was evaluated by two radiologists. In all cases, as seen on power Doppler ultrasonography, infarcted areas-when compared with normal parenchyma, clearly demonstrated wedge-shaped perfusion defects in the kidney. The location of the lesion closely corresponded to the location seen during CT scanning. After renal arterial occlusion, transiently congested capsular arteries, which were named 'capsular sign', were seen in 63% of rabbits in the two and five-hour groups. No significant cortical rim sign was demonstrated on power Doppler ultrasonography, though it was noted on spiral CT at 15 and 24 hours, and 3 and 7 days after renal arterial occlusion. Power Doppler ultrasonography was useful for the diagnosis of renal infarction. Congested capsular artery seen in the early stage of renal infarction might be a characteristic finding of this condition, as seen on power Doppler ultrasonography

  5. Pulmonary spheral tuberculosis: features and clinical significance of spiral dynamic CT

    International Nuclear Information System (INIS)

    Xie Ruming; Ma Daqing; Li Tieyi; Chen Yi; Lu Fudong; Zhou Xinhua

    2001-01-01

    Objective: To assess the features and clinical significance of spiral dynamic CT in patients with pulmonary spheral tuberculosis. Methods: The 54 foci in 42 patients with pulmonary spheral tuberculosis were studied. Thin-sections at 2 mm thickness and 2 mm interval through the nodular center were obtained before and after administration of contrast material. Results: In 54 pulmonary spheral tuberculosis, maximum enhanced CT value in 51 (94.4%, 51/54) foci was less than 20 HU, and more than 20 HU in the other 3(5.6%, 3/54) foci. 27(50.0%, 27/54) foci showed no any enhancement, 24, (44%, 24/54) foci showed capsular enhancement, 1(1.9%, 1/54) focus showed peripheral enhancement and 2(3.7%, 2/54) foci showed extensive enhancement. The accuracy of the correct diagnosis was 25.9% in terms of plain CT and 94.4% in terms of enhanced CT scanning. The difference was significant (x 2 = 50.1, P < 0.05). The curative effect of extensive enhanced foci and peripheral enhanced foci was optimal, capsular enhanced foci was second, and non-enhanced foci was barely satisfactory. Conclusion: Spiral dynamic CT technique may improve the accuracy of diagnosing pulmonary spheral tuberculosis. No enhancement and/or capsular enhancement were suggestive of tuberculosis. The enhancing character of foci might contribute to assess the curative effect of anti-tuberculosis

  6. Noninvasive diagnosis of suspected severe pulmonary embolism. Trans-esophageal echocardiography vs spiral CT

    International Nuclear Information System (INIS)

    Pruszczyk, P.; Torbicki, A.; Pacho, R.

    1998-01-01

    Patients with pulmonary embolism (PE) and echocardiographic signs of right ventricular over-lead have worse prognosis and may be require aggressive therapy. Unequivocal confirmation of PE is required before thrombolysis or embolectomy. This study compares the value of trans-esophageal echocardiography (TEE) and spiral CT (sCT) in direct visualization of pulmonary artery thrombo-emboli in patients with suspected PE and echocardiographic signs of right ventricular over-lead. Because of high prevalence of bilateral central pulmonary thrombo-emboli in patients with hemo-dynamically significant PE, both sCT and TEE allow its definitive confirmation in most cases. Thrombi reported by sCT distally to lobar arteries should be interpreted with caution. (author)

  7. The value of multi-slice spiral CT in the preoperative assessment of living renal donor

    International Nuclear Information System (INIS)

    Li Qinghai; Yan Fuhua; Xu Pengju; Zhou Meiling; Zhu Tongyu; Xu Ming; Wang Guomin

    2008-01-01

    Objective: The purpose of this study is to assess the value of multi-slice spiral CT (MSCT) in the preoperative evaluation of living renal donor as a all in one modality. Methods: Thirty-six potential living renal donors underwent the examination using a GE light VCT scanner. Informed consent was obtained from all participants. The plain scan, early arterial phase, late arterial phase and excretory phase scans are performed in the former 25 donors (injection rate 5 rolls, total volume 100 mi, tube tension 120 kV). While in the later 11 donors (2 ml/s 40 ml +4 ml/s 60 ml), the scanning protocol included the plain scan ( 100 kV), vascular phase and excretory phase scans (100 kV). The excretory phase data were used in the reconstruction of CT urography in both groups. All images were reviewed by one radiologist and one urologist, and the findings of MSCT were compared with intraoperative findings for 33 donors, to investigate the utilities of MSCT in assessing renal vascularity, urinary tract and lesions of renal parenchyma. When discrepancies are found between the two reviewers, consensus was obtained via discussion. Au data was statiscally processed with SPSS for Windows. Results: MSCT angiography is in accordance with intraoperative findings in demonstrating the anatomy of renal arteries and renal vein trunk, accesary arteries, early branching of renal artery. The findings from CTA are highly in accordance with the intraoperative findings, which facilitate intraoperative ligation and reduce relevant complications. CTU demonstrates the anatomy of urinary, tract in good agreement with the intraoperative findings. The image quality of 3D vascularity and CTU between the two groups, scored 4.4 ± 1.2 vs 4.2 ± 1.3 and 4.6 ± 0.8 vs 4.4 ± 0.9 respectively, no statistical between-groups difference was found (Z=-0.89, -0.47, P>0.05). Conclusion: MSCT multiphase scanning combined with CTA and CTU play a important role in the evaluation of living renal donor, which

  8. Spiral CT biliary virtual endoscopy: preliminary clinical applications in the detection of biliary calculus

    International Nuclear Information System (INIS)

    Xiong Minghui; Wang Dong; Song Yunlong; Zhang Wanshi; Xu Jiaxing

    2000-01-01

    Objective: To evaluate imaging features and clinical value of CT biliary virtual endoscopy in the detection of biliary calculus. Methods: Eighteen patients with biliary calculi underwent volume scanning using spiral CT (Hispeed Advantage CT/i GE ). All data were transferred to computer workstation, and CT biliary virtual endoscopy images with pseudocolor encoding were generated from the volumetric data using the Navigator Smooth soft-ware. All cases were proved by ultrasound, axial CT or operation. Results: Among 18 cases, gallstones were found 8 in cases, common bile duct stones in 2 cases, gallstones and bile duct stones in 6 cases. The stones were 0.3-3.2 cm in size. CT biliary virtual endoscopy correctly demonstrated the surface details of stones which were viewed from extra- or intraluminal orientation in a 3D fashion. The findings were consistent with those of US, CT or operation. Conclusion: The CT virtual biliary endoscopy is a further development of virtual endoscopy for observing biliary calculus from intra- and extra-luminal views and providing three dimensional information of stone

  9. Visual classification of emphysema heterogeneity compared with objective measurements: HRCT vs spiral CT in candidates for lung volume reduction surgery

    International Nuclear Information System (INIS)

    Cederlund, K.; Hoegberg, S.; Rasmussen, E.; Svane, B.; Bergstrand, L.; Tylen, U.; Aspelin, P.

    2002-01-01

    The aim of this study was to investigate whether spiral CT is superior to high-resolution computed tomography (HRCT) in evaluating the radiological morphology of emphysema, and whether the combination of both CT techniques improves the evaluation in patients undergoing lung volume reduction surgery (LVRS). The material consisted of HRCT (with 2-mm slice thickness) and spiral CT (with 10-mm slice thickness) of 94 candidates for LVRS. Selected image pairs from these examinations were evaluated. Each image pair consisted of one image from the cranial part of the lung and one image from the caudal part. The degree of emphysema in the two images was calculated by computer. The difference between the images determined the degree of heterogeneity. Five classes of heterogeneity were defined. The study was performed by visual classification of 95 image pairs (spiral CT) and 95 image pairs (HRCT) into one of five different classes of emphysema heterogeneity. This visual classification was compared with the computer-based classification. Spiral CT was superior to HRCT with 47% correct classifications of emphysema heterogeneity compared with 40% for HRCT-based classification (p<0.05). The combination of the techniques did not improve the evaluation (42%). Spiral CT is superior to HRCT in determining heterogeneity of emphysema visually, and should be included in the pre-operative CT evaluation of LVRS candidates. (orig.)

  10. Visual classification of emphysema heterogeneity compared with objective measurements: HRCT vs spiral CT in candidates for lung volume reduction surgery

    Energy Technology Data Exchange (ETDEWEB)

    Cederlund, K.; Hoegberg, S.; Rasmussen, E.; Svane, B. [Department of Thoracic Radiology, Karolinska Hospital, Stockholm (Sweden); Bergstrand, L. [Department of Radiology, Danderyds Hospital, Danderyd (Sweden); Tylen, U. [Deparment of Radiology, Sahlgrenska University Hospital, Gothenberg (Sweden); Aspelin, P. [Department of Radiology, Huddinge University Hospital, Huddinge (Sweden)

    2002-05-01

    The aim of this study was to investigate whether spiral CT is superior to high-resolution computed tomography (HRCT) in evaluating the radiological morphology of emphysema, and whether the combination of both CT techniques improves the evaluation in patients undergoing lung volume reduction surgery (LVRS). The material consisted of HRCT (with 2-mm slice thickness) and spiral CT (with 10-mm slice thickness) of 94 candidates for LVRS. Selected image pairs from these examinations were evaluated. Each image pair consisted of one image from the cranial part of the lung and one image from the caudal part. The degree of emphysema in the two images was calculated by computer. The difference between the images determined the degree of heterogeneity. Five classes of heterogeneity were defined. The study was performed by visual classification of 95 image pairs (spiral CT) and 95 image pairs (HRCT) into one of five different classes of emphysema heterogeneity. This visual classification was compared with the computer-based classification. Spiral CT was superior to HRCT with 47% correct classifications of emphysema heterogeneity compared with 40% for HRCT-based classification (p<0.05). The combination of the techniques did not improve the evaluation (42%). Spiral CT is superior to HRCT in determining heterogeneity of emphysema visually, and should be included in the pre-operative CT evaluation of LVRS candidates. (orig.)

  11. Pitfalls in the use of spiral CT for identification of intracranial aneurysms

    International Nuclear Information System (INIS)

    Young, N.; Kingston, R.J.; Dorsch, N.W.C.

    1999-01-01

    We describe problems encountered in our first 136 patients, with 95 aneurysms, who underwent spiral CT for investigation of possible aneurysms involving the circle of Willis and adjacent major vessels, and who had surgical and/or angiographic confirmation. There were seven false-positive cases, of which the first three could be explained by operator inexperience. There were four false negatives, all small aneurysms; two were not seen because of operator error and two were hidden by an adjacent larger aneurysm. Clip artefacts prevented diagnostic studies in six of 21 postoperative studies. One aneurysm was outside the CT field of view, being on a pericallosal artery. One basilar artery tip aneurysm was excluded from the field of the CT study because of a planning error. Inspection of the axial source images is critical if the diagnosis of small or thrombosed aneurysms is to be made. Close attention to image acquisition and computer modelling is required to reduce errors in spiral CT angiography of intracranial aneurysms. (orig.)

  12. Risk-benefit analysis and cost-effectiveness analysis of lung cancer screening by spiral CT

    International Nuclear Information System (INIS)

    Iinuma, Takeshi

    1999-01-01

    Mass screening of lung cancer has been widely performed using indirect chest X-ray method in Japan. However reduction of the mortality for lung cancer is questioned. We have proposed that recently developed spiral CT should be adopted for the screening of lung cancer, since CT has an excellent detectability for small nodule. Lung Cancer Screening CT (LSCT) has been developed by author's group using spiral CT with low dose and light weight in order to make a mobile unit. In this paper risk-benefit analysis and cost-effectiveness analysis are described for the LSCT screening of lung cancer. As a risk, radiation carcinogenesis due to exposure from LSCT are compared with gain of life-expectancy by screening and men of 40 years or more and women of 45 years or more are justified. The cost per person-year is estimated for LSCT screening which is better than that of present method, although total cost is higher. The LSCT screening could be recommended if total cost is affordable. (author)

  13. Analysis of hepatic vein variations in healthy people with 64-slice spiral CT

    International Nuclear Information System (INIS)

    Zhang Rong; Li Yong; Shen Jun; Zeng Weike; Li Jieting; Huang Suiqiao; Liang Biling; Liu Chao

    2007-01-01

    Objective: To analyze variations of hepatic vein in healthy people with 64-slice spiral CT. Methods: Seventy-five healthy subjects underwent multi-slice spiral computed (MSCT) hepatic venography. The anatomy of the junction of the hepatic veins with the inferior vena cava and the intrahepatic drainage territory of the hepatic veins and tributaries were evaluated. The hepatic veins were classified according to three anatomic classification (Nakamura's, Marcos's and Kawasaki's classification) methods respectively. Results: There was a common trunk of the middle and left hepatic veins before joining the IVC in 86.7% (65/75)of the cases. In 13.3% (10/75)of the cases, the three main hepatic veins joined the IVC separately. The ratios of Nakamma's classification type A, B, C of hepatic veins were 49.4% (37/75), 37.3% (28/75), and 13.3% (10/75) respectively. The ratios of Marcos's classification type A, B, C of hepatic veins were 56.0% (42/75), 24.0% (18/75), and 20.0% (15/75) respectively. The ratios of Kawasaki's classification type I, II of hepatic vein were 40.0% (30/75) and 60.0% (45/75). Conclusion: Multi-slice spiral CT hepatic venography can provide visualization of peripheral hepatic venous branches in details. (authors)

  14. Kymogram detection and kymogram-correlated image reconstruction from subsecond spiral computed tomography scans of the heart

    International Nuclear Information System (INIS)

    Kachelriess, Marc; Sennst, Dirk-Alexander; Maxlmoser, Wolfgang; Kalender, Willi A.

    2002-01-01

    Subsecond single-slice, multi-slice or cone-beam spiral computed tomography (SSCT, MSCT, CBCT) offer great potential for improving heart imaging. Together with the newly developed phase-correlated cardiac reconstruction algorithms 180 deg. MCD and 180 deg. MCI [Med. Phys. 27, 1881-1902 (2000)] or related algorithms provided by the CT manufacturers, high image quality can be achieved. These algorithms require information about the cardiac motion, i.e., typically the simultaneously recorded electrocardiogram (ECG), to synchronize the reconstruction with the cardiac motion. Neither data acquired without ECG information (standard patients) nor acquisitions with corrupted ECG information can be handled adequately. We developed a method to extract the appropriate information about cardiac motion directly from the measured raw data (projection data). The so-called kymogram function is a measure of the cardiac motion as a function of time t or as a function of the projection angle α. In contrast to the ECG which is a global measure of the heart's electric excitation, the kymogram is a local measure of the heart motion at the z-position z(α) at projection angle α. The patient's local heart rate as well as the necessary synchronization information to be used with phase-correlated algorithms can be extracted from the kymogram by using a series of signal processing steps. The kymogram information is shown to be adequate to substitute the ECG information. Computer simulations with simulated ECG and patient measurements with simultaneously acquired ECG were carried out for a multislice scanner providing M=4 slices to evaluate these new approaches. Both the ECG function and the kymogram function were used for reconstruction. Both were highly correlated regarding the periodicity information used for reconstruction. In 21 out of 25 consecutive cases the kymogram approach was equivalent to the ECG-correlated reconstruction; only minor differences in image quality between both

  15. Evaluation of spiral CT in staging of colon and rectum carcinoma

    International Nuclear Information System (INIS)

    Hundt, W.; Braunschweig, R.; Reiser, M.

    1999-01-01

    The purpose of our study was to evaluate the capability of a subsecond spiral-CT scanner using two contrast medium phases in staging of colorectal cancer. In our study we included 37 patients with proven rectum or colon carcinoma. Spiral CT was performed following tap-water enema of the colon in the arterial and venous phases of contrast medium enhancement. Our results were compared with the findings of pathological examination after surgery. The tumor's size and extension were evaluated in the arterial and venous phases, the lymph nodes in the venous phase of the CT scan. The tumor was in the rectum (n = 14), sigma (n = 11), descending colon (n = 6), and cecum (n = 6). Two-phase spiral CT had a sensitivity of 97.2 % in the arterial phase and 89.1 % in the venous phase in detecting the carcinoma. The staging results were in the arterial phase in 30 of 37 cases (81.0 %) and in the venous phase in 24 of 37 cases (64.8 %) according to pathology. In 27 of 32 patients (84.3 %) lymph nodes were detected. The correct classification of the N-stage was possible in 23 of 34 cases (67.6 %). The combined use of arterial and venous phases in staging of colorectal cancer can improve the T- and N-stage classification in comparison with using only one contrast medium phase. The arterial phase is superior compared with the venous phase for local tumor staging and the venous phase is used for lymph node assessment. (orig.) (orig.)

  16. Spiral CT scanning technique in the detection of aspiration of LEGO foreign bodies

    International Nuclear Information System (INIS)

    Applegate, K.E.; Dardinger, J.T.; Herts, B.R.; Davros, W.J.; Obuchowski, N.A.; Lieber, M.L.; Maneker, A.

    2001-01-01

    Background:. Radiolucent foreign bodies (FBs) such as plastic objects and toys remain difficult to identify on conventional radiographs of the neck and chest. Children may present with a variety of respiratory complaints, which may or may not be due to a FB. Objective: To determine whether radiolucent FBs such as plastic LEGOs and peanuts can be seen in the tracheobronchial tree or esophagus using low-dose spiral CT, and, if visible, to determine the optimal CT imaging technique. Materials and methods: Multiple spiral sequences were performed while varying the CT parameters and the presence and location of FBs in either the trachea or the esophagus first on a neck phantom and then a cadaver. Sequences were rated by three radiologists blinded to the presence of a FB using a single scoring system. Results: The LEGO was well visualized in the trachea by all three readers (both lung and soft-tissue windowing: combined sensitivity 89 %, combined specificity 89 %) and to a lesser extent in the esophagus (combined sensitivity 31 %, combined specificity 100 %). The peanut was not well visualized (combined sensitivity < 35 %). The optimal technique for visualizing the LEGO was 120 kV, 90 mA, 3-mm collimation, 0.75 s/revolution, and 2.0 pitch. This allowed for coverage of the cadaver tracheobronchial tree (approximately 11 cm) in about 18 s. Although statistical power was low for detecting significant differences, all three readers noted higher average confidence ratings with lung windowing among 18 LEGO-in-trachea scans. Conclusion: Rapid, low-dose spiral CT may be used to visualize LEGO FBs in the airway or esophagus. Peanuts were not well visualized. (orig.)

  17. Spiral CT scanning technique in the detection of aspiration of LEGO foreign bodies.

    Science.gov (United States)

    Applegate, K E; Dardinger, J T; Lieber, M L; Herts, B R; Davros, W J; Obuchowski, N A; Maneker, A

    2001-12-01

    Radiolucent foreign bodies (FBs) such as plastic objects and toys remain difficult to identify on conventional radiographs of the neck and chest. Children may present with a variety of respiratory complaints, which may or may not be due to a FB. To determine whether radiolucent FBs such as plastic LEGOs and peanuts can be seen in the tracheobronchial tree or esophagus using low-dose spiral CT, and, if visible, to determine the optimal CT imaging technique. Multiple spiral sequences were performed while varying the CT parameters and the presence and location of FBs in either the trachea or the esophagus first on a neck phantom and then a cadaver. Sequences were rated by three radiologists blinded to the presence of a FB using a single scoring system. The LEGO was well visualized in the trachea by all three readers (both lung and soft-tissue windowing: combined sensitivity 89 %, combined specificity 89 %) and to a lesser extent in the esophagus (combined sensitivity 31 %, combined specificity 100 %). The peanut was not well visualized (combined sensitivity LEGO was 120 kV, 90 mA, 3-mm collimation, 0.75 s/revolution, and 2.0 pitch. This allowed for coverage of the cadaver tracheobronchial tree (approximately 11 cm) in about 18 s. Although statistical power was low for detecting significant differences, all three readers noted higher average confidence ratings with lung windowing among 18 LEGO-in-trachea scans. Rapid, low-dose spiral CT may be used to visualize LEGO FBs in the airway or esophagus. Peanuts were not well visualized.

  18. Compressed sensing reconstruction of cardiac cine MRI using golden angle spiral trajectories.

    Science.gov (United States)

    Tolouee, Azar; Alirezaie, Javad; Babyn, Paul

    2015-11-01

    In dynamic cardiac cine Magnetic Resonance Imaging (MRI), the spatiotemporal resolution is limited by the low imaging speed. Compressed sensing (CS) theory has been applied to improve the imaging speed and thus the spatiotemporal resolution. The purpose of this paper is to improve CS reconstruction of under sampled data by exploiting spatiotemporal sparsity and efficient spiral trajectories. We extend k-t sparse algorithm to spiral trajectories to achieve high spatio temporal resolutions in cardiac cine imaging. We have exploited spatiotemporal sparsity of cardiac cine MRI by applying a 2D+time wavelet-Fourier transform. For efficient coverage of k-space, we have used a modified version of multi shot (interleaved) spirals trajectories. In order to reduce incoherent aliasing artifact, we use different random undersampling pattern for each temporal frame. Finally, we have used nonuniform fast Fourier transform (NUFFT) algorithm to reconstruct the image from the non-uniformly acquired samples. The proposed approach was tested in simulated and cardiac cine MRI data. Results show that higher acceleration factors with improved image quality can be obtained with the proposed approach in comparison to the existing state-of-the-art method. The flexibility of the introduced method should allow it to be used not only for the challenging case of cardiac imaging, but also for other patient motion where the patient moves or breathes during acquisition. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Diagnostic value of multi-slice spiral CT for atlantoaxial spine injuries in children

    International Nuclear Information System (INIS)

    Xia Chengde; Qin Hongwei; Li Junhong

    2009-01-01

    Objective: To evaluate the diagnostic value of multi-slice spiral CT (MSCT) for the atlantoaxial spine injuries in children. Methods: The CT findings of 21 cases with the atlantoaxial spine injuries in children were reviewed retrospectively. Results: Fractures of dens occurred in 4 cases, isolated atlantoaxial dislocation in 15 cases, subluxation of the C2/3 right vertebra facet in 1 and atlanto-occipital subluxation in 1. CT diagnosis was correct in all cases. And plain film diagnosis was correct ia 13. Conclusion: MSCT could clearly demonstrate the fractures and dislocations of the atlantoaxial spine injuries in children and correctly determine the type of the atlantoaxial spine injuries in children, MSCT is the modality of choice in diagnosis of the atlantoaxial spine injuries in children and should be performed routinely. (authors)

  20. Reconstruction of Cochlea Based on Micro-CT and Histological Images of the Human Inner Ear

    Directory of Open Access Journals (Sweden)

    Christos Bellos

    2014-01-01

    Full Text Available The study of the normal function and pathology of the inner ear has unique difficulties as it is inaccessible during life and, so, conventional techniques of pathologic studies such as biopsy and surgical excision are not feasible, without further impairing function. Mathematical modelling is therefore particularly attractive as a tool in researching the cochlea and its pathology. The first step towards efficient mathematical modelling is the reconstruction of an accurate three dimensional (3D model of the cochlea that will be presented in this paper. The high quality of the histological images is being exploited in order to extract several sections of the cochlea that are not visible on the micro-CT (mCT images (i.e., scala media, spiral ligament, and organ of Corti as well as other important sections (i.e., basilar membrane, Reissner membrane, scala vestibule, and scala tympani. The reconstructed model is being projected in the centerline of the coiled cochlea, extracted from mCT images, and represented in the 3D space. The reconstruction activities are part of the SIFEM project, which will result in the delivery of an infrastructure, semantically interlinking various tools and libraries (i.e., segmentation, reconstruction, and visualization tools with the clinical knowledge, which is represented by existing data, towards the delivery of a robust multiscale model of the inner ear.

  1. Dose reduction in pediatric abdominal CT: use of iterative reconstruction techniques across different CT platforms

    International Nuclear Information System (INIS)

    Khawaja, Ranish Deedar Ali; Singh, Sarabjeet; Otrakji, Alexi; Padole, Atul; Lim, Ruth; Nimkin, Katherine; Westra, Sjirk; Kalra, Mannudeep K.; Gee, Michael S.

    2015-01-01

    Dose reduction in children undergoing CT scanning is an important priority for the radiology community and public at large. Drawbacks of radiation reduction are increased image noise and artifacts, which can affect image interpretation. Iterative reconstruction techniques have been developed to reduce noise and artifacts from reduced-dose CT examinations, although reconstruction algorithm, magnitude of dose reduction and effects on image quality vary. We review the reconstruction principles, radiation dose potential and effects on image quality of several iterative reconstruction techniques commonly used in clinical settings, including 3-D adaptive iterative dose reduction (AIDR-3D), adaptive statistical iterative reconstruction (ASIR), iDose, sinogram-affirmed iterative reconstruction (SAFIRE) and model-based iterative reconstruction (MBIR). We also discuss clinical applications of iterative reconstruction techniques in pediatric abdominal CT. (orig.)

  2. Dose reduction in pediatric abdominal CT: use of iterative reconstruction techniques across different CT platforms

    Energy Technology Data Exchange (ETDEWEB)

    Khawaja, Ranish Deedar Ali; Singh, Sarabjeet; Otrakji, Alexi; Padole, Atul; Lim, Ruth; Nimkin, Katherine; Westra, Sjirk; Kalra, Mannudeep K.; Gee, Michael S. [MGH Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States)

    2015-07-15

    Dose reduction in children undergoing CT scanning is an important priority for the radiology community and public at large. Drawbacks of radiation reduction are increased image noise and artifacts, which can affect image interpretation. Iterative reconstruction techniques have been developed to reduce noise and artifacts from reduced-dose CT examinations, although reconstruction algorithm, magnitude of dose reduction and effects on image quality vary. We review the reconstruction principles, radiation dose potential and effects on image quality of several iterative reconstruction techniques commonly used in clinical settings, including 3-D adaptive iterative dose reduction (AIDR-3D), adaptive statistical iterative reconstruction (ASIR), iDose, sinogram-affirmed iterative reconstruction (SAFIRE) and model-based iterative reconstruction (MBIR). We also discuss clinical applications of iterative reconstruction techniques in pediatric abdominal CT. (orig.)

  3. Ancillary lung parenchymal findings at spiral CT scanning in pulmonary embolism. Relationship to chest sonography

    International Nuclear Information System (INIS)

    Reissig, Angelika; Heyne, Jens-Peter; Kroegel, Claus

    2004-01-01

    Introduction/objective: The aim of the study was to compare findings of transthoracic sonography (TS) and of spiral computed tomography (sCT) in patients with suspected pulmonary embolism (PE). Methods and patients: Peripheral parenchymal and pleural findings of TS and sCT were compared in 62 patients (25 females, 37 males; mean age 62.2 years) with suspected PE. Results: In 39 patients PE was established, of whose pleura-based lesions could be detected by TS in 30 patients and by sCT in 31 patients. Whilst in three of the patients parenchymal lesions were exclusively detected by sonography, no peripheral abnormalities could be discovered with either technique in five patients. Among the nine patients lacking peripheral abnormalities on sonography, four revealed peripheral lesions in sCT. In 23 patients without PE, peripheral consolidations at CT were detected in six patients whereas two showed lesions on TS. With respect to the appearance, pleura-based wedge-shaped consolidations were the main parenchymal alterations (82.4% at TS, 66.1% at sCT) as compared with non-wedge-shaped consolidations (17.6% at TS, 33.9% at sCT). Peripheral lesions were located preferentially within the lower lobes. In addition, both localised and basal pleural effusion associated with PE could be demonstrated in 58.9% at TS and in 23.1% by sCT. Discussions and conclusion: The study shows that in PE parenchymal and pleural changes are detectable by TS and sCT. If parenchymal findings are present at sCT, peripheral PE should be considered, even in the absence of directly visible emboli

  4. Ancillary lung parenchymal findings at spiral CT scanning in pulmonary embolism. Relationship to chest sonography

    Energy Technology Data Exchange (ETDEWEB)

    Reissig, Angelika E-mail: angelika.reissig@med.uni-jena.de; Heyne, Jens-Peter; Kroegel, Claus

    2004-03-01

    Introduction/objective: The aim of the study was to compare findings of transthoracic sonography (TS) and of spiral computed tomography (sCT) in patients with suspected pulmonary embolism (PE). Methods and patients: Peripheral parenchymal and pleural findings of TS and sCT were compared in 62 patients (25 females, 37 males; mean age 62.2 years) with suspected PE. Results: In 39 patients PE was established, of whose pleura-based lesions could be detected by TS in 30 patients and by sCT in 31 patients. Whilst in three of the patients parenchymal lesions were exclusively detected by sonography, no peripheral abnormalities could be discovered with either technique in five patients. Among the nine patients lacking peripheral abnormalities on sonography, four revealed peripheral lesions in sCT. In 23 patients without PE, peripheral consolidations at CT were detected in six patients whereas two showed lesions on TS. With respect to the appearance, pleura-based wedge-shaped consolidations were the main parenchymal alterations (82.4% at TS, 66.1% at sCT) as compared with non-wedge-shaped consolidations (17.6% at TS, 33.9% at sCT). Peripheral lesions were located preferentially within the lower lobes. In addition, both localised and basal pleural effusion associated with PE could be demonstrated in 58.9% at TS and in 23.1% by sCT. Discussions and conclusion: The study shows that in PE parenchymal and pleural changes are detectable by TS and sCT. If parenchymal findings are present at sCT, peripheral PE should be considered, even in the absence of directly visible emboli.

  5. Detection of pulmonary metastases with pathological correlation: effect of breathing on the accuracy of spiral CT. Editor`s note

    Energy Technology Data Exchange (ETDEWEB)

    Coakley, F.V. [Abdominal Imaging Section, Department of Radiology, University of California, San Francisco, CA (United States); Cohen, M.D. [Department of Radiology, Riley Hospital for Children, Indianapolis, IN (United States); Waters, D.J. [Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN (United States); Davis, M.M. [Department of Pathology, Riley Hospital for Children, Indianapolis, IN (United States); Karmazyn, B. [Department of Radiology, Riley Hospital for Children, Indianapolis, IN (United States); Gonin, R. [Division of Biostatistics, Department of Medicine, Riley Hospital for Children, Indianapolis, IN (United States); Hanna, M.P. [Division of Biostatistics, Department of Medicine, Riley Hospital for Children, Indianapolis, IN (United States)

    1997-07-01

    Background. CT of the chest for suspected pulmonary metastases in adults is generally performed using a breath-hold technique. The results may not be applicable to young children in whom breath-holding may be impossible. Objective. Determine the effect of breathing on the accuracy of pulmonary metastasis detection by spiral CT (SCT). Materials and methods. Prior to euthanasia four anesthetized dogs with metastatic osteosarcoma underwent SCT with a collimation of 5 mm and a pitch of 2, during both induced breath-hold and normal quiet breathing. Images were reconstructed as contiguous 5-mm slices. Macroscopically evident metastases were noted at postmortem. Hard-copy SCT images were reviewed by ten radiologists, each of whom circled all suspected metastases. SCT images were compared with postmortem results to determine true and false positives. Results. The pathologist identified 132 macroscopically evident pulmonary metastases. For metastasis detection, there was no significant difference between breath-hold SCT and breathing SCT. Conclusion. In our animal model, SCT can be performed during normal resting breathing without significant loss of accuracy in the detection of pulmonary metastases. (orig.). With 3 tabs.

  6. Detection of pulmonary metastases with pathological correlation: effect of breathing on the accuracy of spiral CT. Editor's note

    International Nuclear Information System (INIS)

    Coakley, F.V.; Cohen, M.D.; Waters, D.J.; Davis, M.M.; Karmazyn, B.; Gonin, R.; Hanna, M.P.

    1997-01-01

    Background. CT of the chest for suspected pulmonary metastases in adults is generally performed using a breath-hold technique. The results may not be applicable to young children in whom breath-holding may be impossible. Objective. Determine the effect of breathing on the accuracy of pulmonary metastasis detection by spiral CT (SCT). Materials and methods. Prior to euthanasia four anesthetized dogs with metastatic osteosarcoma underwent SCT with a collimation of 5 mm and a pitch of 2, during both induced breath-hold and normal quiet breathing. Images were reconstructed as contiguous 5-mm slices. Macroscopically evident metastases were noted at postmortem. Hard-copy SCT images were reviewed by ten radiologists, each of whom circled all suspected metastases. SCT images were compared with postmortem results to determine true and false positives. Results. The pathologist identified 132 macroscopically evident pulmonary metastases. For metastasis detection, there was no significant difference between breath-hold SCT and breathing SCT. Conclusion. In our animal model, SCT can be performed during normal resting breathing without significant loss of accuracy in the detection of pulmonary metastases. (orig.). With 3 tabs

  7. The comparative study of various oral contrast media in 3D display of gastric lesions in spiral CT

    International Nuclear Information System (INIS)

    Wu Dong; Zhou Kangrong; Peng Weijun

    2001-01-01

    Objective: To optimize the oral contrast media in three-dimensional display of gastric lesions. Methods: 41 cases were randomly divided into 3 groups according to different oral contrast media administered: No. 1 air contrast group (n = 17), No. 2 fat emulsion group (n = 7) and No. 3 positive contrast group (n = 25). The 3D CT images were reconstructed using MPR, SSD, RaySum display and virtual endoscopic techniques, and compared with gastric endoscopy and/or conventional barium study. Results: The detectability of gastric lesions using fat emulsion and air contrast was 42.8%(3/7) and 80.0%(20/25), respectively, both were significantly lower than that using positive contrast (100%, 30/30) (x 2 = 19.22, P 2 = 6.60, P 2 = 17.04, P < 0.01). Conclusion: It is very important to choose the appropriate oral contrast media for 3D display of gastric lesions in spiral CT, the positive contrast agent is the optimal choice

  8. Dose reduction in spiral CT angiography of thoracic outlet syndrome by anatomically adapted tube current modulation

    International Nuclear Information System (INIS)

    Mastora, I.; Remy-Jardin, M.; Remy, J.; Suess, C.; Scherf, C.; Guillot, J.P.

    2001-01-01

    The aim of this study was to evaluate dose reduction in spiral CT angiography of the thoracic outlet by on-line tube-current control. Prospectively, 114 patients undergoing spiral CT angiography of the subclavian artery for thoracic outlet arterial syndromes were evaluated with and without tube-current modulation at the same session (scanning parameters for the two successive angiograms, one in the neutral position and one after the postural maneuver): 140 kV; 206 mA; scan time 0.75 s; collimation 3 mm; pitch = (1). The dose reduction system was applied in the neutral position in the first 92 consecutive patients and after postural maneuver in the remaining 22 consecutive patients. Dose reduction and image quality were analyzed in the overall study group (group 1; n = 114). The influence of the arm position was assessed in 44 of the 114 patients (group 2), matched by the transverse diameter of the upper thorax. The mean dose reduction was 33 % in group 1 (range 22-40 %) and 34 % in group 2 (range 26-40 %). In group 2 the only difference in image quality was a significantly higher frequency of graininess on low-dose scans compared with reference scans whatever the patient's arm position, graded as minimal in 38 of the 44 patients (86 %). When the low-dose technique was applied after postural maneuver in group 2: (a) the mean dose reduction was significantly higher (35 vs 32 % in the neutral position; p = 0.006); (b) graininess was less frequent (82 vs 91 % in the neutral position); and (c) the percentage of graininess graded as minimal was significantly higher (83 vs 70 % in the neutral position; p = 0.2027). On-line tube-current modulation enables dose reduction on high-quality, diagnostic spiral CT angiograms of the thoracic outlet and should be applied during data acquisition in the neutral position and after postural maneuver for optimal use. (orig.)

  9. Dose reduction in spiral CT angiography of thoracic outlet syndrome by anatomically adapted tube current modulation

    Energy Technology Data Exchange (ETDEWEB)

    Mastora, I.; Remy-Jardin, M.; Remy, J. [Dept. of Radiology, University Center Hospital Calmette, Lille (France); Medical Research Group, Lille (France); Suess, C.; Scherf, C. [Siemens Medical Systems, Forcheim (Germany); Guillot, J.P. [Dept. of Radiology, University Center Hospital Calmette, Lille (France)

    2001-04-01

    The aim of this study was to evaluate dose reduction in spiral CT angiography of the thoracic outlet by on-line tube-current control. Prospectively, 114 patients undergoing spiral CT angiography of the subclavian artery for thoracic outlet arterial syndromes were evaluated with and without tube-current modulation at the same session (scanning parameters for the two successive angiograms, one in the neutral position and one after the postural maneuver): 140 kV; 206 mA; scan time 0.75 s; collimation 3 mm; pitch = (1). The dose reduction system was applied in the neutral position in the first 92 consecutive patients and after postural maneuver in the remaining 22 consecutive patients. Dose reduction and image quality were analyzed in the overall study group (group 1; n = 114). The influence of the arm position was assessed in 44 of the 114 patients (group 2), matched by the transverse diameter of the upper thorax. The mean dose reduction was 33 % in group 1 (range 22-40 %) and 34 % in group 2 (range 26-40 %). In group 2 the only difference in image quality was a significantly higher frequency of graininess on low-dose scans compared with reference scans whatever the patient's arm position, graded as minimal in 38 of the 44 patients (86 %). When the low-dose technique was applied after postural maneuver in group 2: (a) the mean dose reduction was significantly higher (35 vs 32 % in the neutral position; p = 0.006); (b) graininess was less frequent (82 vs 91 % in the neutral position); and (c) the percentage of graininess graded as minimal was significantly higher (83 vs 70 % in the neutral position; p = 0.2027). On-line tube-current modulation enables dose reduction on high-quality, diagnostic spiral CT angiograms of the thoracic outlet and should be applied during data acquisition in the neutral position and after postural maneuver for optimal use. (orig.)

  10. Different contrast injection protocols for 64-slice spiral CT coronary angiography

    International Nuclear Information System (INIS)

    Lu Jinguo; Lv Bing; Bai Hua; Tang Xiang; Yang Xinling; Jiang Shiliang; Dai Ruiping; Qiu Jinhai; Chen Tao

    2008-01-01

    Objective: To determine the optimal contrast protocols for 64-slice spiral CT coronary angiography in order to reduce the volume of contrast injection. Methods: One hundred fifty patients scheduled to undergo 64-slice spiral CT coronary angiography were prospectively randomized into the following five groups with different injection protocols: group 1: uniphasic injection without a flush; group 2: biphasic injection with a flush; group 3, group 4 and group 5 : triphasic injection with a diluted contrast material with 3:7, 5:5, 7:3 contrast/saline ratio respectively. Attenuation was measured in the right atrium, right ventricle, left atrium, left ventricle, ascending aorta, right coronary artery and left coronary artery and analyzed with single factor variance test (ANOVA). The quality of the coronary artery images was evaluated and compared using person Chi-Square. Results: The total contrast material volume were (67.0±5.3) ml, (59.9±4.9) ml, (62.9±3.2) ml, (69.2±5.7) ml and (70.9±4.6) ml in five groups respectively (F=27.43, P 2 =18.81, P 2 =31.44, P<0.01). The artifacts in the superior vena cava in group 1 was the most, and in group 2 was the least. The mean enhancement values of right and left coronary arteries in group 2 were significantly greater than those in other groups (F=2.47 and 4.10, P<0.05). The visualization of both left ventricle and right ventricle cavities was the best in group 3. Conclusion: Biphasic injection and triphasic injection are better than uniphasic injection for 64-slice spiral CT coronary angiography and triphasic injection is better than biphasic injection for the visualization of both left ventricle and right ventricle cavities. (authors)

  11. Spiral CT angiography and surgical correlations in the evaluation of intracranial aneurysms

    International Nuclear Information System (INIS)

    Preda, L.; Di Maggio, E.M.; La Fianza, A.; Dore, R.; Fulle, I.; Solcia, M.; Campani, R.; Gaetani, P.; Rodriguez y Baena, R.; Cecchini, A.; Infuso, L.

    1998-01-01

    We investigated the accuracy of spiral computed tomography angiography (CTA) in the detection and study of intracranial aneurysms by comparing CTA with selective angiograms and surgical findings. Twenty-six patients (9 men and 17 women; mean age 53.1 ± 1.8 years) with suspected intracranial aneurysms were submitted to CTA (1- to 2-mm slices, pitch 1:1, 24 s, RI = 1) after a conventional CT examination showing subarachnoid hemorrhage (SAH) in 19 cases and during neuroradiological investigations performed for other reasons in 7 cases. One hundred twenty to 150 ml iodate contrast agent (0.3-0.4 gI/ml) were injected intravenously at 5 ml/s rate and with 12- to 25-s delay calculated with a preliminary test bolus. Three-dimensional shaded surface display (3D SSD) and maximum intensity projection (MIP) reconstructions were obtained from axial images. Then, within 48 h, all patients were submitted to digital subtraction angiography (DSA), with separate assessment of CTA and DSA findings. Twenty-two aneurysms shown by CTA were confirmed at DSA and surgery (true positives), whereas the vascular lesion was not confirmed at DSA in 2 cases (false positives). The presence of intracranial aneurysms was excluded at both CTA and subsequent DSA in 7 cases (true negatives) and there were no false negatives; sensitivity was 100 %, specificity 77.8 %, and diagnostic accuracy 93.5 %. Computed tomography angiography aneurysm location was confirmed at surgery in all cases, with very high accuracy in assessing the presence of an aneurysm neck (100 %). Computed tomography angiography accurately depicted the aneurysm shape in 20 of 22 cases, but failed to depict its multilobed nature in 2 cases. The mean aneurysm diameter calculated at CTA was 0.99 ± 0.12 cm vs 1.09 ± 0.11 cm at surgery (p < 0.01). The present results suggest that the high sensitivity of CTA, if confirmed by further studies, might help in avoiding having to resort to arteriography after negative CTA in SAH patients. (orig.)

  12. [Diprosopus triophthalmus. From ancient terracotta sculptures to spiral computer tomographic reconstruction].

    Science.gov (United States)

    Sokiranski, R; Pirsig, W; Nerlich, A

    2005-03-01

    A still-born male fetus from the 19th century, fixed in formalin and presenting as diprosopia triophthalmica, was analysed by helical computer tomography and virtually reconstructed without damage. This rare, incomplete, symmetrical duplication of the face on a single head with three eyes, two noses and two mouths develops in the first 3 weeks of gestation and is a subset of the category of conjoined twins with unknown underlying etiology. Spiral computer tomography of fixed tissue demonstrated in the more than 100 year old specimen that virtual reconstruction can be performed in nearly the same way as in patients (contrast medium application not possible). The radiological reconstruction of the Munich fetus, here confined to head and neck data, is the basis for comparison with a number of imaging procedures of the last 3000 years. Starting with some Neolithic Mesoamerican ceramics, the "Pretty Ladies of Tlatilco", diprosopia triophthalmica was also depicted on engravings of the 16th and 17th century A.D. by artists as well as by the anatomist Soemmering and his engraver Berndt in the 18th century. Our modern spiral computer tomography confirms the ability of our ancestors to depict diprosopia triophthalmica in paintings and sculptures with a high level of natural precision.

  13. Reconstruction CT imaging of the hypopharynx and the larynx

    International Nuclear Information System (INIS)

    Okuno, Tetsuji; Fujimura, Akiko; Murakami, Yasushi; Shiga, Hayao

    1986-01-01

    The multiplanar reconstruction CT imaging of the hypopharynx and the larynx was performed on a total of 20 cases: 8 with laryngeal carcinomas, 6 with hypopharyngeal carcinomas, 4 with vocal cord paralyses due to various causes, 1 with laryngeal amyloidosis, 1 with inflammatory granuloma of the hypopharynx. Coronal, segittal, and parasagittal reconstruction images were obtained from either 1 or 2 mm overlapping axial scans with 4 or 5 mm slice thickness (3 cases) using 5 sec scan times during queit breathing. In 15 cases with coronal reconstruction imaging, the anatomical derangements of the laryngopharyngeal structures especially along the undersurface of the true vocal cord to the false cord level, the lateral wall of the pyriform sinus, and the paraglottic space were demonstrated more clearly than the axial CT imaging. In 5 cases with sagittal reconstruction imaging, the vertical extension of the lesions through the anterior commisure was more clearly depicted than the axial CT imaging. In 8 cases with parasagittal reconstruction imaging, which is along the vocal fold or across the aryepiglottic fold, pathological changes along the aryepiglottic fold, the arytenoid-corniculate cartilage complex, and the tip of the pyriform sinus were more clearly demonstrated than the axial CT imaging. In determining the feasibility of conservation surgery of the larynx and the hypopharynx, reconstruction CT imaging is recommended as the diagnostic procedure of a choice, which would supplement the findings of the routine axial CT imaging. (author)

  14. The Role of Spiral Multidetector Dynamic CT in the Study of Williams-Campbell Syndrome

    International Nuclear Information System (INIS)

    Scioscio, V. di; Zompatori, M.; Mistura, I.; Montanari, P.; Santilli, L.; Luccaroni, R.; Sverzellati, N.

    2006-01-01

    Williams-Campbell syndrome is a cystic bronchiectatic disease secondary to deficiency or defect of cartilaginous plates in the wall of the airways. In the literature, two main forms are suggested: congenital and acquired (post-infectious). The most frequent symptoms are represented by recurrent pulmonary infections from childhood. Multislice spiral dynamic CT has a major role in the study of cystic pulmonary disease and in differentiating Williams-Campbell syndrome from the other causes of cystic bronchiectasis, in which even lung function tests can give deceptive results

  15. The Role of Spiral Multidetector Dynamic CT in the Study of Williams-Campbell Syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Scioscio, V. di; Zompatori, M.; Mistura, I.; Montanari, P.; Santilli, L.; Luccaroni, R.; Sverzellati, N. [Medical Univ. of Bologna, S. Orsola-Malpighi Policlinic (Italy). Dept. of Radiology

    2006-10-15

    Williams-Campbell syndrome is a cystic bronchiectatic disease secondary to deficiency or defect of cartilaginous plates in the wall of the airways. In the literature, two main forms are suggested: congenital and acquired (post-infectious). The most frequent symptoms are represented by recurrent pulmonary infections from childhood. Multislice spiral dynamic CT has a major role in the study of cystic pulmonary disease and in differentiating Williams-Campbell syndrome from the other causes of cystic bronchiectasis, in which even lung function tests can give deceptive results.

  16. Iterative CT reconstruction via minimizing adaptively reweighted total variation.

    Science.gov (United States)

    Zhu, Lei; Niu, Tianye; Petrongolo, Michael

    2014-01-01

    Iterative reconstruction via total variation (TV) minimization has demonstrated great successes in accurate CT imaging from under-sampled projections. When projections are further reduced, over-smoothing artifacts appear in the current reconstruction especially around the structure boundaries. We propose a practical algorithm to improve TV-minimization based CT reconstruction on very few projection data. Based on the theory of compressed sensing, the L-0 norm approach is more desirable to further reduce the projection views. To overcome the computational difficulty of the non-convex optimization of the L-0 norm, we implement an adaptive weighting scheme to approximate the solution via a series of TV minimizations for practical use in CT reconstruction. The weight on TV is initialized as uniform ones, and is automatically changed based on the gradient of the reconstructed image from the previous iteration. The iteration stops when a small difference between the weighted TV values is observed on two consecutive reconstructed images. We evaluate the proposed algorithm on both a digital phantom and a physical phantom. Using 20 equiangular projections, our method reduces reconstruction errors in the conventional TV minimization by a factor of more than 5, with improved spatial resolution. By adaptively reweighting TV in iterative CT reconstruction, we successfully further reduce the projection number for the same or better image quality.

  17. Spiral CT and optimization of the modalities of the iodinated intravenous contrast material: Experimental studies in human pathology

    International Nuclear Information System (INIS)

    Bonaldi, V.

    1998-01-01

    Spiral (or helical) CT represents the most recent improvement in the field of computed assisted tomography (CAT scan). The capabilities of this new imaging modality are much superior to these of conventional CT scanning; then result from the rapid acquisition and from the volumetric nature of the derived data set. The short time of data acquisition had made mandatory the revision of protocols for intravenous administration of iodinated contrast material. By the means of several studies, carried out on pathologic and healthy patients, we have attempted to improve knowledge in factors influencing CT attenuation values after injection of contrast material, in the aim of improving contrast administration performed during spiral CT scanning. Anatomical landmarks that we have studied till now have been liver, the pancreas, the kidney and the cervical spine. In addition, a paired based methodology has been used. The volumetric set of data derived from spiral CT scanning leads to optimal post-processing tasks, the most interesting being related to cine-display and multiplanar reformatting; both modalities have been evaluated, about the pancreas and the musculo-skeletal system respectively. Conversely, this new modality, as for other imaging modalities, is responsible for additional costs derived from restless increase in the number of images to be dealt with and from the occurrence of new tasks (in post-processing particularly). The place of spiral CT in diagnostic strategies among other modern imaging modalities should be assessed, especially with respect to Magnetic Resonance Imaging (MRI). (author)

  18. Spiral-CT-angiography of acute pulmonary embolism: factors that influence the implementation into standard diagnostic algorithms

    International Nuclear Information System (INIS)

    Bankier, A.; Herold, C.J.; Fleischmann, D.; Janata-Schwatczek, K.

    1998-01-01

    Purpose: Debate about the potential implementation of Spiral-CT in diagnostic algorithms of pulmonary embolism are often focussed on sensitivity and specificity in the context of comparative methodologic studies. We intend to investigate whether additional factors might influence this debate. Results: The factors availability, acceptance, patient-outcome, and cost-effectiveness-studies do have substantial influence on the implementation of Spiral-CT in the diagnostic algorithms of pulmonary embolism. Incorporation of these factors into the discussion might lead to more flexible and more patient-oriented algorithms for the diagnosis of pulmonary embolism. Conclusion: Availability of equipment, acceptance among clinicians, patient-out-come, and cost-effectiveness evaluations should be implemented into the debate about potential implementation of Spiral-CT in routine diagnostic imaging algorithms of pulmonary embolism. (orig./AJ) [de

  19. Use of spiral CT in demonstrating early carcinoma of the stomach - I stage

    International Nuclear Information System (INIS)

    Pomakov, P.

    2009-01-01

    Full text: The aim of this lecture is to provide practical information about the methodology and technique of spiral computed tomography, which provide maximum diagnostic efficiency in early gastric cancer - I stage, and to present the semiotics of CT images seen in early gastric cancer stage I - a own and literature data. Methodology of the study covers optimal drug muscle relaxation of the abdominal wall by injection of 2 sg buskolizin intravenous; maximum distension of the stomach lumen by ingestion of 3 effervescent disintegrated tablets Vit. C with 1-2 sips of water, necessarily using of non-ionic contrast media - 100 ml / 300 mg iodine / 1 ml liquid bolus introduced for 30 seconds. Start scanning - 30 seconds of the start of injection - to visualize the arterial phase, use of slices with a thickness of 3 mm and 2 mm interval; exponential data 120 kV, 160 mAc. Earlier form of gastric cancer have to be presented by 5 CT image: unequal unsmooth, scallop or polycyclic contours of the lining, thinning the complete disappearance of the lining; undulating thickening of the lining; nodal formation like a polyp on a broad basis with a 2-5 mm, double contour of the lining - like a wave. These amendments are localized only in a limited segment of the gastric mucosa. Spiral CT is an effective diagnostic performance in gastric cancer, including the early stage I of cancer development. This is realized only by using the specific methodology of the study as well as good knowledge of the CT images semiology for carcinoma, localized only within a certain perimeter of the stomach lining

  20. Adaptive enhancement of optical fringe patterns by selective reconstruction using FABEMD algorithm and Hilbert spiral transform.

    Science.gov (United States)

    Trusiak, Maciej; Patorski, Krzysztof; Wielgus, Maciej

    2012-10-08

    Presented method for fringe pattern enhancement has been designed for processing and analyzing low quality fringe patterns. It uses a modified fast and adaptive bidimensional empirical mode decomposition (FABEMD) for the extraction of bidimensional intrinsic mode functions (BIMFs) from an interferogram. Fringe pattern is then selectively reconstructed (SR) taking the regions of selected BIMFs with high modulation values only. Amplitude demodulation and normalization of the reconstructed image is conducted using the spiral phase Hilbert transform (HS). It has been tested using computer generated interferograms and real data. The performance of the presented SR-FABEMD-HS method is compared with other normalization techniques. Its superiority, potential and robustness to high fringe density variations and the presence of noise, modulation and background illumination defects in analyzed fringe patterns has been corroborated.

  1. Brachytherapy reconstruction using orthogonal scout views from the CT

    International Nuclear Information System (INIS)

    Perez, J.; Lliso, F.; Carmona, V.; Bea, J.; Tormo, A.; Petschen, I.

    1996-01-01

    Introduction: CT assisted brachytherapy planning is demonstrating to have great advantages as external RT planning does. One of the problems we have found in this approach with the conventional gynecological Fletcher applicators is the high amount of artefacts (ovoids with rectal and vessical protections) in the CT slice. We have introduced a reconstruction method based on scout views in order to avoid this problem, allowing us to perform brachytherapy reconstruction completely CT assisted. We use a virtual simulation chain by General Electric Medical Systems. Method and discussion: Two orthogonal scout views (0 and 90 tube positions) are performed. The reconstruction method takes into account the virtual position of the focus and the fact that there is only divergence in the transverse plane. Algorithms developed for sources as well as for reference points localisation (A, B, lymphatic Fletcher trapezoid, pelvic wall, etc.) are presented. This method has the following practical advantages: the porte-cassette is not necessary, the image quality can be improved (it is very helpful in pelvic lateral views that are critical in conventional radiographs), the total time to get the data is smaller than for conventional radiographs (reduction of patient motion effects) and problems that appear in CT-slice based reconstruction in the case of strongly curved intrauterine applicators are avoided. Even though the resolution is smaller than in conventional radiographs it is good enough for brachytherapy. Regarding the CT planning this method presents the interesting feature that the co-ordinate system is the same for the reconstruction process that for the CT-slices set. As the application can be reconstructed from scout views and the doses can be evaluated on CT slices it is easier to correlate the dose values obtained for the traditional points with those provided by the CT information

  2. Spiral CT features of abdomen after whipple's operation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, T. H.; Lee, K. Y.; Shin, K. H.; Jung, M. H.; Park, C. M.; Cha, I. H. [Korea Univ. College of Medicine, Seoul (Korea, Republic of)

    1997-04-01

    To assess the CT features of postoperative anatomical changes, surgical complications, and patterns of tumor recurrence after Whipple's operation. 42 spiral CT scans of 31 patients who had undergone Whipple's operation were retrospectively reviewed. Postoperative diagnoses were distal CBD cancer in 13 patients, cancer of the ampulla of Vater in ten, cancer of the head of the pancreas in seven, and microcystic cystadenocarcinoma of the pancreas in one. Time intervals between surgery and CT ranged from 1 week to 5 years. CT features of postoperative anastomotic changes, surgical complications, and patterns of tumor recurrence were analyzed. Gastro- or duodeno-jejunal anastomosis was seen in 32 CT scans(74%), pancreaticojejunostomy in 27(64%), and choledochojejunostomy in 24(57%). Pneumobilia was seen in ten patients(34%). Abnormal fluid collections in the peripancreatic and perihepatic space were demonstrated in two patients who underwent CT scans within 3 weeks after operation. Other complications included wound abscess(n=2), and portal vein occlusion(n=1). The most common site of metastasis was the lymph node(n=8)(retroperitoneal:n=5; mesentery root:n=4; and celiac:n=2), followed by the liver(n=6), peritoneum(n=3), adrenal gland(n=2), and afferent loop(n=1). In three cases, there was local recurrence in the pancreatic bed. To reduce possible diagnostic errors during CT interpretation, a Knowledge of normal postoperative anatomy, common complications, and patterns of disease recurrence following Whipple's operation is important.

  3. Reconstructing misaligned x-ray CT data

    Energy Technology Data Exchange (ETDEWEB)

    Divin, C. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-24

    Misalignment errors for x-ray computed tomography (CT) systems can manifest as artifacts and a loss of spatial and contrast resolution. To mitigate artifacts, significant effort is taken to determine the system geometry and minimizing any residual error in the system alignment. This project improved our ability to post-correct data which was acquired on a misaligned CT system.

  4. The clinical application studies of CT spinal angiography with 64-detector row spiral CT in diagnosing spinal vascular malformations

    International Nuclear Information System (INIS)

    Gao Sijia; Zhang Mengwei; Liu Xiping; Zh Yushen; Liu Jinghong; Wang Zhonghui; Zang Peizhuo; Shi Qiang; Wang Qiang; Liang Chuansheng; Xu Ke

    2009-01-01

    Background and purpose: To explore the value of CT spinal angiography with 64-detector row spiral CT in diagnosing spinal vascular malformations. Methods: Seventeen patients with initial MR and clinical findings suggestive of spinal vascular diseases underwent CT spinal angiography. Among these, 14 patients took DSA examination within 1 week after CT scan, 7 patients underwent surgical treatment, and 6 patients underwent vascular intervention embolotheraphy. CT protocol: TOSHIBA Aquilion 64 Slice CT scanner, 0.5 mm thickness, 0.5 s/r, 120 kV and 350 mA, positioned at the aortic arch level, and applied with 'sure start' technique with CT threshold of 180 Hu. Contrast agent Iohexol (370 mg I/ml) was injected at 6 ml/s velocity with total volume of 80 ml. The post-processing procedures included MPR, CPR, MIP, VR, etc. Among the 17 patients, four patients underwent fast dynamic contrast-enhanced 3D MR angiography imaging. CT spinal angiography and three-dimensional contrast-enhanced MR angiography (3D CE-MRA) images were compared and evaluated with DSA and operation results based on disease type, lesion range, feeding arteries, fistulas, draining veins of vascular malformation by three experienced neuroradiologists independently, using double blind method. The data were analyzed using SPSS analytic software with χ 2 -test. We compared the results with DSA and operation results. Results: The statistical analysis of the diagnostic results by the three experienced neuroradiologists had no statistical difference (P > 0.05). All of the 17 patients showed clearly the abnormality of spinal cord vessels and the range of lesions by CT spinal angiography. Among them, one patient was diagnosed as arteriovenous fistulas (AVF) by MRI and CT spinal angiography, which was verified by surgical operation. DSA of the same patient, however, did not visualize the lesion. One case was diagnosed as AVM complicated with AVF by DSA, but CT spinal angiography could only show AVM not AVF. The

  5. The clinical application studies of CT spinal angiography with 64-detector row spiral CT in diagnosing spinal vascular malformations

    Energy Technology Data Exchange (ETDEWEB)

    Gao Sijia [Department of Radiology, No. 1 Affiliated Hospital of China Medical University, Shenyang 110001 (China)], E-mail: scarlettgao@126.com; Zhang Mengwei; Liu Xiping; Zh Yushen; Liu Jinghong; Wang Zhonghui [Department of Radiology, No. 1 Affiliated Hospital of China Medical University, Shenyang 110001 (China); Zang Peizhuo [Department of Neurosurgery, No. 1 Affiliated Hospital of China Medical University, Shenyang 110001 (China); Shi Qiang; Wang Qiang [Department of Radiology, No. 1 Affiliated Hospital of China Medical University, Shenyang 110001 (China); Liang Chuansheng [Department of Neurosurgery, No. 1 Affiliated Hospital of China Medical University, Shenyang 110001 (China); Xu Ke [Department of Radiology, No. 1 Affiliated Hospital of China Medical University, Shenyang 110001 (China)

    2009-07-15

    Background and purpose: To explore the value of CT spinal angiography with 64-detector row spiral CT in diagnosing spinal vascular malformations. Methods: Seventeen patients with initial MR and clinical findings suggestive of spinal vascular diseases underwent CT spinal angiography. Among these, 14 patients took DSA examination within 1 week after CT scan, 7 patients underwent surgical treatment, and 6 patients underwent vascular intervention embolotheraphy. CT protocol: TOSHIBA Aquilion 64 Slice CT scanner, 0.5 mm thickness, 0.5 s/r, 120 kV and 350 mA, positioned at the aortic arch level, and applied with 'sure start' technique with CT threshold of 180 Hu. Contrast agent Iohexol (370 mg I/ml) was injected at 6 ml/s velocity with total volume of 80 ml. The post-processing procedures included MPR, CPR, MIP, VR, etc. Among the 17 patients, four patients underwent fast dynamic contrast-enhanced 3D MR angiography imaging. CT spinal angiography and three-dimensional contrast-enhanced MR angiography (3D CE-MRA) images were compared and evaluated with DSA and operation results based on disease type, lesion range, feeding arteries, fistulas, draining veins of vascular malformation by three experienced neuroradiologists independently, using double blind method. The data were analyzed using SPSS analytic software with {chi}{sup 2}-test. We compared the results with DSA and operation results. Results: The statistical analysis of the diagnostic results by the three experienced neuroradiologists had no statistical difference (P > 0.05). All of the 17 patients showed clearly the abnormality of spinal cord vessels and the range of lesions by CT spinal angiography. Among them, one patient was diagnosed as arteriovenous fistulas (AVF) by MRI and CT spinal angiography, which was verified by surgical operation. DSA of the same patient, however, did not visualize the lesion. One case was diagnosed as AVM complicated with AVF by DSA, but CT spinal angiography could only show

  6. Quantitative evaluation in enhancement of pancreas and adjacent vessels during spiral CT

    International Nuclear Information System (INIS)

    Kim, Hyoung Seuk; Shin, Kue Hee; Park, Cheol Min; Cha, Sang Hoon; Chung, Kyoo Byung

    1997-01-01

    To determine by quantitative evaluation of pancreatic and adjacent vascular enhancement during spiral CT, the ideal scan delay for examination of the pancreas. Dual(n=3D90) and triple(n=3D90) phase spiral CT scans of patients whose pancreas showed no pathologic condition were retrospectively evaluated. Dual-phase scans were performed at 43 seconds(early), and 5-6 minutes(delayed) after the injection of 120ml of contrast material at an injection rate of 3ml/sec;triple-phase scans were performed at 25 seconds(arterial),60-65 seconds (portal) and 5-6 minutes (delayed) after the injection of 120-140ml of contrast material at an injection rate of 2-4ml/sec, and ten patients also underwent precontrast scanning. CT attenuation values(HU) were measured in the head, body and tail of the pancreas, aorta, and main portal vein during each phase of all scans. Triple-phase protocol was used to measure the effect of different total volumes and injection rates on enhancement of the pancreas and adjacent vessels. There was no significant difference in the degree of enhancement of the pancreas head, body and tail during each phase(p>0.05). The pancreas was maximally enhanced on 43 second delayed scan(132±20HU)(p 0.05). The main portal vein showed maximum enhancement on 43-second delayed scan(207±44HU)(p<0.05). Different total volume of contrast material did not change the enhancement of the pancreas and adjacent vessels. At an injection rate of 2ml/sec, peak enhancement of the pancreas, aorta and portal vein was obtained on 60-65 second delayed scan, and at 4ml/sec, peak enhancement was obtained on 25 second delayed scan(p<0.05). Observing the usual protocols for abdominal spiral CT scanning, the pancreas was most effectively evaluated using a 43-second delayed scan. An increased injection rate resulted in earlier enhancement of the pancreas, aorta and portal vein

  7. Malignant focal hepatic lesions complicating underlying liver disease: dual-phase contrast-enhanced spiral CT sensitivity and specificity in orthotopic liver transplant patients

    International Nuclear Information System (INIS)

    Mortele, K.J.; De Keukeleire, K.; Praet, M.; Van Vlierberghe, H.; Hemptinne, B. de; Ros, P.R.

    2001-01-01

    The aim of this study was to determine the accuracy of contrast-enhanced biphasic spiral CT as a screening tool in the preoperative evaluation of orthotopic liver transplant (OLT) patients. Spiral-CT examinations were performed before liver transplantation in 53 patients. Scans were retrospectively reviewed and compared with pathologic findings in fresh-sectioned livers. When findings between spiral CT and pathology were discordant, formalized livers were reexamined with lesion-by lesion evaluation. Fresh pathologic evaluation revealed 23 liver lesions (16 HCC, 7 macro-regenerative nodules). Malignancy was identified in 13 of 53 patients (24.5%). Pre-transplantation spiral CT depicted 27 liver lesions (23 HCC, 4 macro-regenerative nodules). Malignancy was suspected in 14 patients (26.4%). In 10 of 53 (18.9%), spiral CT and pathologic evaluation were discordant. Subsequent retrospective pathologic evaluation showed malignancy in 4 additional patients. Spiral CT compared with the retrospective pathologic findings revealed 36 real-negative, 14 real-positive, 0 false-positive, and 3 false-negative patients with malignancy. Sensitivity and specificity of spiral CT in detection of malignancy was 82 and 100%, respectively. Contrast-enhanced biphasic spiral CT is an accurate technique in the evaluation of patients preceding OLT. Routine fresh-sectioned liver pathologic findings are not as sensitive as previously estimated. (orig.)

  8. Correlation between spiral CT features of pericolic infiltration and tumor angiogenesis in colorectal carcinoma

    International Nuclear Information System (INIS)

    Zhang Ruiping; Li Jianding

    2007-01-01

    Objective: To investigate the correlation of spiral CT (SCT) features with pathology, microvessel density (MVD), expression of vascular endothelial growth factor (VEGF), matrix metalloproteinase-2( MMP-2) in colorectal carcinoma. Methods: Forty patients with colorectal carcinoma confirmed by operation were examined by SCT. The resected tumor specimens were immunohistochemically stained for the expression of VEGF, MMP-2 and the calculation of MVD. Results: The accuracy of SCT in depicting the pericolic and wall infiltration was 92.5%. The metastasis rates of colorectal cancer with pericolic infiltration and wall infiltration were 75.0% and 33.3%, respectively, the differences were statistically significant between the two groups (P<0.05). The differences of CT enhancement value, MVD, expressions of VEGF and MMP-2 between the two groups were statistically significant (P<0.05). The enhancement degree of CT had a positive correlation with MVD (P<0.05). Conclusion: SCT is accurate for depicting pericolic and wall infiltration, pericolic infiltration in colorectal carcinoma indicates the tendency of metastasis. The enhancement degree of CT might be used to quantitatively evaluate the tumor angiogenesis, expressions of VEGF and MMP-2 and MVD are closely correlated with the infiltration of colorectal cancer. (authors)

  9. The usefulness of levin tube inserted drip infusion spiral CT: comparison with conventional method in subtotal gastrectomy patients

    International Nuclear Information System (INIS)

    Park, Young Jin; Kim, Young Hwan; Yoon, Jung Hee; Cha, Soon Joo; Kim, Jeong Sook; Kim, Sung Rok; Hur, Gham; Rhim, Hyun Chul

    1998-01-01

    The purpose of this study is to access the usefulness of newly designed Levin tube inserted drip infusion spiral CT for the evaluation of remnant stomach and anastomosis site in patients who have undergone subtotal gastrectomy for stomach cancer. A new technique named Levin tube inserted drip infusion spiral CT was used to prospectively study 23 patients. A 16Fr Levin tube was inserted into the remnant stomach; 500 ml of tap water was drip infused just before CT scanning and an additional 500 ml of water was infused during IV contrast injection. Water was infused by gravity, using a water bottle suspended at a height of 90 cm (Group A). The 31 patients who underwent conventional spiral CT scanning immediately after the divided ingestion of 900 ml diluted gastrografin were selected as a control group (Group B). The anatomic delineation of the anastomosis site was graded by two radiologists as excellent (3), good(2), fair (1) or poor (0). To evaluate the degree of distension, the maximal diameters of remnant stomach and the anastomosis site, and the thickness of the stomach wall, were also measured. In patients who had undergone subtobal gastrectomy, Levin tube inserted drip infusion spiral CT showed excellent anatomic delineation of the site of anastomosis and remnant stomach. We found that because it increases the distension of remnant stomach and the anastomosis site, this technique is effective for the evaluation of postoperative stomach. (author). 10 refs., 2 tabs., 3 figs

  10. Iterative CT reconstruction with correction for known rigid motion

    Energy Technology Data Exchange (ETDEWEB)

    Nuyts, Johan [Katholieke Univ. Leuven (Belgium). Dept. of Nuclear Medicine; Kim, Jung-Ha; Fulton, Roger [Sydney Univ., NSW (Australia). School of Physics; Westmead Hospital, Sydney (Australia). Medical Physics

    2011-07-01

    In PET/CT brain imaging, correction for motion may be needed, in particular for children and psychiatric patients. Motion is more likely to occur in the lengthy PET measurement, but also during the short CT acquisition patient motion is possible. Rigid motion of the head can be measured independently from the PET/CT system with optical devices. In this paper, we propose a method and some preliminary simulation results for iterative CT reconstruction with correction for known rigid motion. We implemented an iterative algorithm for fully 3D reconstruction from helical CT scans. The motion of the head is incorporated in the system matrix as a view-dependent motion of the CT-system. The first simulation results indicate that some motion patterns may produce loss of essential data. This loss precludes exact reconstruction and results in artifacts in the reconstruction, even when motion is taken into account. However, by reducing the pitch during acquisition, the same motion pattern no longer caused artifacts in the motion corrected image. (orig.)

  11. Detection of tibial condylar fractures using 3D imaging with a mobile image amplifier (Siemens ISO-C-3D): Comparison with plain films and spiral CT

    International Nuclear Information System (INIS)

    Kotsianos, D.; Rock, C.; Wirth, S.; Linsenmaier, U.; Brandl, R.; Fischer, T.; Pfeifer, K.J.; Reiser, M.; Euler, E.; Mutschler, W.

    2002-01-01

    Purpose: To analyze a prototype mobile C-arm 3D image amplifier in the detection and classification of experimental tibial condylar fractures with multiplanar reconstructions (MPR). Method: Human knee specimens (n=22) with tibial condylar fractures were examined with a prototype C-arm (ISO-C-3D, Siemens AG), plain films (CR) and spiral CT (CT). The motorized C-arm provides fluoroscopic images during a 190 orbital rotation computing a 119 mm data cube. From these 3D data sets MP reconstructions were obtained. All images were evaluated by four independent readers for the detection and assessment of fracture lines. All fractures were classified according to the Mueller AO classification. To confirm the results, the specimens were finally surgically dissected. Results: 97% of the tibial condylar fractures were easily seen and correctly classified according to the Mueller AO classification on MP reconstruction of the ISO-C-3D. There is no significant difference between ISO-C and CT in detection and correct classification of fractures, but ISO-CD-3D is significant by better than CR. (orig.) [de

  12. Measurements of computed tomography dose index for axial and spiral CT scanners

    International Nuclear Information System (INIS)

    Breiki, G; Abbas, Y.; Diab, H.M.; Gomaa, M

    2007-01-01

    The energy deposited in the patient by the rotating x-ray beam in computed tomography produces more uniform absorbed dose values within the section of imaged tissue than those produced in conventional radiological procedures. The dose values within a specific section are determined by factors such as voltage, current, scan field, rotation angle, filtration, collimation, and section thickness and spacing. This study is a part of extensive project, aiming to investigate practice of computed tomography at various hospitals and to implement a Reference Dose Levels (RDLs) to routine CT examinations in Egypt. The dosimetric quantities proposed in the European Guidelines (EG) for CT are weighted computed tomography dose index (CTDI w ) for a single slice and dose-length product (DLP) for a complete examination. Patient-related data as well as technical parameters for head, chest, abdomen and pelvis examinations were collected for seven CT scanners in public and private hospitals.Dose measurements were performed for both axial and spiral models for a range of CT examinations using CT dosimetry head and body phantoms, and ion chamber designed for CT dosimetry. The determined CTDI w and DLP values were compared with the European Commission reference dose levels (ECRDLs) and also with some international survey results. Mean values of CTDI w had a range of 36-69 m Gy with average 55 m Gy for head, and 11-35 mGy with average 23 mGy for chest, abdomen and pelvis examinations. The current reference CTDI w values are 60 m Gy for adult head and 25 m Gy for adult Abdomen

  13. Multi-slice spiral CT perfusion imaging of chronic obstructive pulmonary disease

    International Nuclear Information System (INIS)

    Shao Yanhui; Qian Nong; Xue Yuejun; Dao Yinhong

    2008-01-01

    Objective: To evaluate the diagnostic value of multi-slice spiral CT (MSCT) perfusion imaging in chronic obstructive pulmonary disease (COPD). Methods: Twenty COPD patients and 20 volunteers underwent 8-row detector spiral CT (MSCT) perfusion imaging using cine scan mode with 5 mm slice thickness, 0.5 s rotation time and a total scan time of 45 s with 5 s intervals. 60 ml contrast agent (300 nag I/ml) were administered at a rate of 4 ml/s from the forearm superficial vein. The imaging data were transferred to a workstation. A time-density curve and pseudo-color map were generated automatically with GE CT perfusion 3 software, the blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface (PS) were measured. Results: Time-density curve was flatter and the peak of the curve was obviously lower in COPD patients than the volunteers. The BF, BV, PS in COPD patients was (24.77±11.49) ml·min -1 ·100 g -1 , (2.48±1.02) ml/100 g and (2.75±1.13) ml· min -1 ·100 g -1 respectively. In volunteers was (290.14±107.59) ml·min -1 ·100 g -1 , (16.51 ± 5.98) ml/100 g, (8.80±3.03) ml·min -1 ·100 g -1 respectively. The MTT in COPD patients and volunteers was (10.58±4.85) s and (4.50±1.71)s respectively. The BF, BV and PS in COPD patients was lower than the volunteers, the MTY was higher (P<0.01). Conclusion: MSCT perfusion imaging is helpful for the diagnosis of COPD. (authors)

  14. Novel iterative reconstruction method with optimal dose usage for partially redundant CT-acquisition

    Science.gov (United States)

    Bruder, H.; Raupach, R.; Sunnegardh, J.; Allmendinger, T.; Klotz, E.; Stierstorfer, K.; Flohr, T.

    2015-11-01

    In CT imaging, a variety of applications exist which are strongly SNR limited. However, in some cases redundant data of the same body region provide additional quanta. Examples: in dual energy CT, the spatial resolution has to be compromised to provide good SNR for material decomposition. However, the respective spectral dataset of the same body region provides additional quanta which might be utilized to improve SNR of each spectral component. Perfusion CT is a high dose application, and dose reduction is highly desirable. However, a meaningful evaluation of perfusion parameters might be impaired by noisy time frames. On the other hand, the SNR of the average of all time frames is extremely high. In redundant CT acquisitions, multiple image datasets can be reconstructed and averaged to composite image data. These composite image data, however, might be compromised with respect to contrast resolution and/or spatial resolution and/or temporal resolution. These observations bring us to the idea of transferring high SNR of composite image data to low SNR ‘source’ image data, while maintaining their resolution. It has been shown that the noise characteristics of CT image data can be improved by iterative reconstruction (Popescu et al 2012 Book of Abstracts, 2nd CT Meeting (Salt Lake City, UT) p 148). In case of data dependent Gaussian noise it can be modelled with image-based iterative reconstruction at least in an approximate manner (Bruder et al 2011 Proc. SPIE 7961 79610J). We present a generalized update equation in image space, consisting of a linear combination of the previous update, a correction term which is constrained by the source image data, and a regularization prior, which is initialized by the composite image data. This iterative reconstruction approach we call bimodal reconstruction (BMR). Based on simulation data it is shown that BMR can improve low contrast detectability, substantially reduces the noise power and has the potential to recover

  15. Novel iterative reconstruction method with optimal dose usage for partially redundant CT-acquisition

    International Nuclear Information System (INIS)

    Bruder, H; Raupach, R; Sunnegardh, J; Allmendinger, T; Klotz, E; Stierstorfer, K; Flohr, T

    2015-01-01

    In CT imaging, a variety of applications exist which are strongly SNR limited. However, in some cases redundant data of the same body region provide additional quanta.Examples: in dual energy CT, the spatial resolution has to be compromised to provide good SNR for material decomposition. However, the respective spectral dataset of the same body region provides additional quanta which might be utilized to improve SNR of each spectral component. Perfusion CT is a high dose application, and dose reduction is highly desirable. However, a meaningful evaluation of perfusion parameters might be impaired by noisy time frames. On the other hand, the SNR of the average of all time frames is extremely high.In redundant CT acquisitions, multiple image datasets can be reconstructed and averaged to composite image data. These composite image data, however, might be compromised with respect to contrast resolution and/or spatial resolution and/or temporal resolution. These observations bring us to the idea of transferring high SNR of composite image data to low SNR ‘source’ image data, while maintaining their resolution.It has been shown that the noise characteristics of CT image data can be improved by iterative reconstruction (Popescu et al 2012 Book of Abstracts, 2nd CT Meeting (Salt Lake City, UT) p 148). In case of data dependent Gaussian noise it can be modelled with image-based iterative reconstruction at least in an approximate manner (Bruder et al 2011 Proc. SPIE 7961 79610J).We present a generalized update equation in image space, consisting of a linear combination of the previous update, a correction term which is constrained by the source image data, and a regularization prior, which is initialized by the composite image data. This iterative reconstruction approach we call bimodal reconstruction (BMR).Based on simulation data it is shown that BMR can improve low contrast detectability, substantially reduces the noise power and has the potential to recover spatial

  16. Application of three-dimensional CT reconstruction cranioplasty

    International Nuclear Information System (INIS)

    Yan Shuli; Yun Yongxing; Wan Kunming; Qiu Jian

    2011-01-01

    Objective: To study the application of three-dimensional CT reconstruction in cranioplasty. Methods: 46 patients with skull defect were divided into two group. One group underwent CT examination and three-dimensional reconstruction, and then the Titanium nets production company manufactured corresponding titanium meshes were shaped those data before the operation. The other group received traditional operation in which titanium meshes were shaped during operation. The average time of operation were compared. Results: The average time of operation of the first group is 86.6±13.6 mins, and that of the second group is 115±15.0 mins. The difference of average operation time between the two groups was statistically significant. Conclusion: Three-dimensional CT reconstruction techniques contribute to shorten the average operation time, reduce the intensity of neurosurgeon's work and the patien's risk. (authors)

  17. Preoperative assessment of gastric artery in patients with gastric cancer by CT angiography on 64-slice spiral CT

    International Nuclear Information System (INIS)

    Tang Lei; Zhang Xiaopeng; Sun Yingshi; Cao Kun; Qi Liping; Cui Yong; Wang Ning

    2010-01-01

    Objective: To evaluate the efficacy of different three-dimensional CTA methods on 64-slice sprial CT in the preoperative assessment of gastric arteries and their variations. Methods: Sixty-six consecutive patients with gastric cancer who underwent 64-slice spiral CT examinations preoperatively were retrospectively studied. To get the STS-MIP images, the thickness of slab was adjusted according to the inner diameter of targeted blood vessels and their cross-layer distribution. After four weeks, the AVVR images of all cases was got by the auto-vessel technique. The demonstration rates and origins of the direct and indirect feeding arteries were analyzed on AVVR and STS-MIP. McNemar tests were used to compare the detection rates of gastric feeding arteries by STS-MIP and AVVR. The relationship between CT value and display rate of vessels was analyzed using independent-samples t test. The variations of blood vessels were analyzed. Results: The display rate of indirect feeding arteries were all 100% (66/66) by STS-MIP and AVVR. The display rates of left gastric artery (LGA) and right gastroepiploic artery (RGEA) were 98.5% (65/66), 100.0% (66/66) and 97.0% (64/66), 100.0% (66/66) by STS-MIP and AVVR respectively. The display rates of right artery (RGA), left gastroepiploic artery (LGEA), short gastric artery (SGA) and posterior gastric artery (RGA), left gastroepiploic artery (LGEA), short gastric artery (SGA) and posterior gastric artery (PGA) by AVVR were lower than those of STS-MIP with statistical significances [RGA: 68.2% (45/66) vs. 98.5% (65/66), P<0.01; LGEA: 53.0% (35/66) vs. 97.0% (64/66), P<0.01; SGA: 7.6%(5/66) vs. 59.1% (39/66), P<0.01; PGA: 18.2% (12/66) vs. 63.6% (42/66), P<0.01]. The demonstration rates of LGEA, RGEA and SGA increased accompanied with the increasing of CT value in celiac axis (LGEA: 35 cases displayed with mean CT value of (272 ± 44) HU, 31 cases did not display with mean CT value of (229 ± 42) HU, t=4.043, P<0.01; RGEA: 64 cases

  18. Detection of lung nodules with low-dose spiral CT: comparison with conventional dose CT

    International Nuclear Information System (INIS)

    Zhu Tianzhao; Tang Guangjian; Jiang Xuexiang

    2004-01-01

    Objective: To investigate the effect of reducing scan dose on the lung nodules detection rate by scanning a lung nodule model at low dose and conventional dose. Methods: The lung and the thoracic cage were simulated by using a cyst filled with water surrounded by a roll bandage. Flour, butter, and paraffin wax were mixed together by a certain ratio to simulate lung nodules of 10 mm and 5 mm in diameter with the CT values ranging from -10 to 50 HU. Conventional-dose scan (240 mA, 140 kV) and low-dose scan of three different levels (43 mA, 140 kV; 50 mA, 120 kV; 75 mA, 80 kV) together with three different pitches (1.0, 1.5, and 2.0) were performed. The images of the simulated nodules were combined with the CT images of a normal adult's upper, middle, and inferior lung. Three radiologists read the images and the number of the nodules they detected including both the real ones and the false-positive ones was calculated to investigate weather there was any difference among different doses, pitch groups, and different locations. Results: The detection rate of the 10 mm and 5 mm nodules was 100% and 89.6% respectively by the low-dose scan. There was no difference between low-dose and conventional-dose CT (χ 2 =0.6907, P>0.70). The detection rate of 5 mm nodules declined when large pitch was used. Conclusion: The detection rates of 10 mm and 5 mm nodules had no difference between low-dose CT and conventional-dose CT. As the pitch augmented, the detection rate for the nodules declined

  19. CT Image Reconstruction in a Low Dimensional Manifold

    OpenAIRE

    Cong, Wenxiang; Wang, Ge; Yang, Qingsong; Hsieh, Jiang; Li, Jia; Lai, Rongjie

    2017-01-01

    Regularization methods are commonly used in X-ray CT image reconstruction. Different regularization methods reflect the characterization of different prior knowledge of images. In a recent work, a new regularization method called a low-dimensional manifold model (LDMM) is investigated to characterize the low-dimensional patch manifold structure of natural images, where the manifold dimensionality characterizes structural information of an image. In this paper, we propose a CT image reconstruc...

  20. The spiral CT manifestations of the blood supply of primary hepatocellular carcinoma: correlation with pathological findings

    International Nuclear Information System (INIS)

    Huang Juan; Zhou Xiangping; Liu Rongbo; Chen Xian; Xu Chongyong; Yan Zhihan; Xu Jianying

    2000-01-01

    Objective: To study the correlation between the CT features of tumor blood supplies and the pathological changes in primary hepatocellular carcinoma (PHCC). Methods: Fifty cases with surgically and pathologically proved PHCC underwent spiral CT scanning (plain + dual-phase). One research group blindly evaluated the CT films obtained. According to tumor contrast enhancement and signals showed on CT, the patterns of PHCC was divided into 4 types: arterial blood supplying, portal blood supplying, arterial combining with portal blood supplying, and poorly blood supplying. Microscopically, PHCC was respectively classified into grade I to IV with Edmonson's standard, and into 4 types (trabecular, pseudo-glandular, compact, scirrhous) with WHO histological grading standard. At last, the CT features of tumor blood supplies were correlated with pathologic changes. Results: 36(72%) cases were supplied by hepatic arterial blood, 6(12%) by arterial combining with portal blood supplying, 4(8%) by portal, and 4(8%) were poorly blood supplying. The patterns of tumor blood supplies in PHCC correlated with tumor cells differentiation (P<0.05). PHCC with better tumor cells differentiation was more associated with portal blood supplies. The patterns of tumor blood supplying in PHCC correlated with the histological type of the tumor cell (P < 0.05). All of the scirrhous PHCC were lack of blood supplies, the entire compact and most of the trabecular PHCC were supplied by a arterial blood. Conclusion: The most of PHCC were supplied by hepatic arterial blood and others were supplied by portal blood, arterial combining with portal blood or lack of blood supplies. Evaluation of tumor blood supplies in PHCC is considered to be useful in differential diagnosis and treatment of PHCC

  1. Fuzzy-neural network in the automatic detection and volumetry of the spleen on spiral CT scans

    International Nuclear Information System (INIS)

    Heitmann, K.R.; Mainz Univ.; Rueckert, S.; Heussel, C.P.; Thelen, M.; Kauczor, H.U.; Uthmann, T.

    2000-01-01

    Purpose: To assess spleen segmentation and volumetry in spiral CT scans with and without pathological changes of splenic tissue. Methods: The image analysis software HYBRIKON is based on region growing, self-organized neural nets, and fuzzy-anatomic rules. The neural nets were trained with spiral CT data from 10 patients, not used in the following evaluation on spiral CT scans from 19 patients. An experienced radiologist verified the results. The true positive and false positive areas were compared in terms to the areas marked by the radiologist. The results were compared with a standard thresholding method. Results: The neural nets achieved a higher accuracy than the thresholding method. Correlation coefficient of the fuzzy-neural nets: 0.99 (thresholding: 0.63). Mean true positive rate: 90% (thresholding: 75%), mean false positive rate: 5% (thresholding>100%). Pitfalls were caused by accessory spleens, extreme changes in the morphology (tumors, metastases, cysts), and parasplenic masses. Conclusions: Self-organizing neural nets combined with fuzzy rules are ready for use in the automatic detection and volumetry of the spleen in spiral CT scans. (orig.) [de

  2. Pulmonary emphysema quantitation with Computed Tomography. Comparison between the visual score with high resolution CT, expiratory density mask with spiral CT and lung function studies

    International Nuclear Information System (INIS)

    Zompatori, Maurizio; Battaglia, Milva; Rimondi, Maria Rita; Vivacqua, Donatella; Biscarini, Manuela; Fasano, Luca; Pacilli, Angela Maria Grazia; Guerrieri, Aldo; Fabbri, Mario; Cavina, Mauro

    1997-01-01

    CT is the most accurate method to detect pulmonary emphysema in vivo. They compared prospectively two different methods for emphysema quantitation in 5 normal volunteers and 20 consecutive patients with chronic obstructive pulmonary disease (COPD). All subjects were submitted to function tests and HRCT; three scans were acquired at preselected levels during inspiration. The type and extent of pulmonary emphysema were defined by two independent observers under blind conditions. Disagreements were subsequently settled by consent. All subjects were also examined with expiratory spiral CT using a density mask program, at two different cut-off levels (-850,-900 HU). Visual score and expiratory spiral density mask values (-850 HU) were significantly correlated (r = 0.86), but the visual extent of emphysema was always higher than shown by expiratory spiral CT. The emphysema extent assessed with both CT methods correlated with the function result of expiratory airflow obstruction and gas diffusion impairment (visual score versus forced expiratory volume in one second: r = -0.81, versus single breath carbon monoxide diffusion: r = -0.78. Spiral expiratory density mask -850 HU versus forced expiratory volume in one second: r = -0.85 versus single breath carbon monoxide diffusion: r = -0.77). When -900 HU was used as the cut-off value for the expiratory density mask, the correlation with single breath carbon monoxide diffusion worsened (r = -0.56). Visual score and expiratory density mask -850 HU gave similar results and permitted COPD patients to be clearly distinguished from normal controls (p < 0.01). They believe the true residual volume should lie somewhere in between the CT value and the function results with the helium dilution technique and conclude that the extent of pulmonary emphysema can be confidently assessed with CT methods. Finally, the simple visual score may be as reliable as such highly sophisticated new methods as the spiral expiratory density mask

  3. Primitive experience of three dimensional multi-slice spiral CT angiography for the follow-up of intracranial aneurysm clipping

    International Nuclear Information System (INIS)

    Yang Yunjun; Chen Weijian; Hu Zhangyong; Wu Enfu; Wang Meihao; Zhuge Qichuan; Zhongming; Cheng Jingliang; Ren Cuiping; Zhang Yong

    2008-01-01

    Objective To evaluate multi-slice three-dimensional CT angiography (MS 3D-CTA) for the follow-up of intracranial aneurysm clipping. Methods: MS 3D-CTA of 16 patients with intracranial aneurysm clipping were retrospectively analyzed. The patients were scanned on a 16-slice spiral CT (GE Lightspeed pro). Volume rendering(VR), thin maximum intensity projection(thin MIP) and multi-planar reconstruction (MPR) were employed in image postprocessing in all cases. Results: There were 17 clips in the 16 patients with aneurysm clipping. Six clips were located at the posterior communicating artery, 5 at the anterior communicating artery, 4 at the middle cerebral artery, and the remaining 2 clips were located at the pericallosal artery, in 1 patient. There were no abnormalities found in the aneurysm clipping region in 7 cases by MS 3D- CTA. There were residual aneurysm in 2 cases, parent artery stenosis in 4 cases, and artery spasm in 3 eases. There was no parent artery occlusion and clip displacement in all cases. VR showed excellent 3D spacial relations between the clip and parent artery in 12 cases, and showed good relations in 3 cases. The 1 case with 2 clips in the pericallosal artery showed heavy beam-hardening artifacts. The size and shape of aneurysm clips were clearly depicted by MPR and thin MIP, while 3D spacial relation of aneurysm clip and parent artery were poorly showed. Conclusion: MS 3D-CTA is a safe and efficient method for the follow-up of intracranialaneurysm clipping. Combined VR with MPR or thin MIP can well reveal postoperative changes after aneurysm clipping. (authors)

  4. Single-level dynamic spiral CT of hepatocellular carcinoma: correlation between imaging features and tumor angiogenesis

    International Nuclear Information System (INIS)

    Chen Weixia; Min Pengqiu; Song Bin; Xiao Bangliang; Liu Yan; Wang Wendong; Chen Xian; Xu Jianying

    2001-01-01

    Objective: To investigate the correlation of the enhancement imaging features of hepatocellular carcinoma (HCC) and relevant parameters revealed by single-level dynamic spiral CT scanning with tumor microvessel counting (MVC). Methods: The study included 26 histopathologically proven HCC patients. Target-slice dynamic scanning and portal venous phase scanning were performed for all patients. The time-density curves were generated with measurement of relevant parameters including: peak value (PV) and contrast enhancement ratio (CER), and the gross enhancement morphology analyzed. Histopathological slides were carefully prepared for the standard F8RA and VEGF immunohistochemical staining and tumor microvessel counting and calculation of VEGF expression percentage of tumor cells. The enhancement imaging features of HCC lesions were correlatively studied with tumor MVC and VEGF expression. Results: Peak value of HCC lesions were 7.9 to 75.2 HU, CER were 3.8% to 36.0%. MVC were 6 to 91, and the VEGF expression percentage were 32.1% to 78.3%. The PV and CER were significantly correlated with tumor tissue MVC (r = 0.508 and 0.423, P < 0.01 and 0.05 respectively). There were no correlations between PV and CER and VEGF expression percentage. Both the patterns of time-density curve and the gross enhancement morphology of HCC lesions were also correlated with tumor MVC, and reflected the distribution characteristics of tumor microvessels within HCC lesions. A close association was found between the likelihood of intrahepatic metastasis of HCC lesions with densely enhanced pseudo capsules and the presence of rich tumor microvessels within these pseudo capsules. Conclusion: The parameters and the enhancement imaging features of HCC lesions on target-slice dynamic scanning are correlated with tumor MVC, and can reflect the distribution characteristics of tumor microvessels within HCC lesions. Dynamic spiral CT scanning is a valuable means to assess the angiogenic activity and

  5. Thin-section spiral CT evaluation of morphologic effects of aging lung in asymptomatic adult subjects

    International Nuclear Information System (INIS)

    Li Kuncheng; Liu Jian; Yang Yanhui; Yao Xinyu; Yin Jianguo; Wang Shiwen; He Zuoxiang

    2006-01-01

    Objective: To evaluate the imaging signs of aging lung in asymptomatic adult subjects by using thin-section spiral CT, and analyze the correlation between the signs and the age of examined cases, as well as probe their clinical application value. Methods: One hundred and six healthy adult subjects were divided into 3 groups: 30 to 44 years (n=31), 45 to 59 years (n=30), and over 60 years (n=45), and all the subjects underwent thin-section spiral CT scans in the upper lung field, the middle lung field and the lower lung field. The evaluation indices included the lung interstitium changes, emphysematous changes, mosaic perfusion, dependent density difference, and pleural thickenning. According to the relative score standard, the above-mentioned indices were totally calculated and converted into the score value. The data were statistically processed with SPSS for Windows. Results: Among the three groups, there were remarkable differences in the indices including the lung interstitium changes, emphysematous changes, and mosaic perfusion, respectively (χ 2 =8.10, 9.73, 15.54, P 2 =3.66, 3.24, P> 0.05). The score values had a significant positive correlation with the age (r=0.709, P<0.01). Conclusion: The signs including the lung interstitium changes, emphysematous changes, mosaic perfusion, the dependent density difference, and pleural thickenning can be found in asymptomatic subjects, and they become prominent as the age increases. HRCT is one of the most important methods for evaluating the early signs of the senile lung. (authors)

  6. Parametric boundary reconstruction algorithm for industrial CT metrology application.

    Science.gov (United States)

    Yin, Zhye; Khare, Kedar; De Man, Bruno

    2009-01-01

    High-energy X-ray computed tomography (CT) systems have been recently used to produce high-resolution images in various nondestructive testing and evaluation (NDT/NDE) applications. The accuracy of the dimensional information extracted from CT images is rapidly approaching the accuracy achieved with a coordinate measuring machine (CMM), the conventional approach to acquire the metrology information directly. On the other hand, CT systems generate the sinogram which is transformed mathematically to the pixel-based images. The dimensional information of the scanned object is extracted later by performing edge detection on reconstructed CT images. The dimensional accuracy of this approach is limited by the grid size of the pixel-based representation of CT images since the edge detection is performed on the pixel grid. Moreover, reconstructed CT images usually display various artifacts due to the underlying physical process and resulting object boundaries from the edge detection fail to represent the true boundaries of the scanned object. In this paper, a novel algorithm to reconstruct the boundaries of an object with uniform material composition and uniform density is presented. There are three major benefits in the proposed approach. First, since the boundary parameters are reconstructed instead of image pixels, the complexity of the reconstruction algorithm is significantly reduced. The iterative approach, which can be computationally intensive, will be practical with the parametric boundary reconstruction. Second, the object of interest in metrology can be represented more directly and accurately by the boundary parameters instead of the image pixels. By eliminating the extra edge detection step, the overall dimensional accuracy and process time can be improved. Third, since the parametric reconstruction approach shares the boundary representation with other conventional metrology modalities such as CMM, boundary information from other modalities can be directly

  7. Two-and three-dimensional CT reconstruction

    International Nuclear Information System (INIS)

    Fishman, E.K.; Ney, D.R.; Magid, D.

    1990-01-01

    This paper determines the optimal imaging sequence for creating two- and three-dimensional (2D/3D) skeletal reconstructions from CT data. A cadaver femur, a bone phantom, and a surgically created fracture were scanned with varying protocols to determine the optimal protocol for creating 2D/3D images. The scanning protocols used varying section thickness (2, 4, and 8 mm) as well as scan spacing (2, 3, 4 and 8 mm). All images were reconstructed into 2D data sets with a bicubic interpolation and 3D datasets with volumetric rendering. The results were reviewed by two reviewers to determine the quality of images reconstruction

  8. High spatial resolution CT image reconstruction using parallel computing

    International Nuclear Information System (INIS)

    Yin Yin; Liu Li; Sun Gongxing

    2003-01-01

    Using the PC cluster system with 16 dual CPU nodes, we accelerate the FBP and OR-OSEM reconstruction of high spatial resolution image (2048 x 2048). Based on the number of projections, we rewrite the reconstruction algorithms into parallel format and dispatch the tasks to each CPU. By parallel computing, the speedup factor is roughly equal to the number of CPUs, which can be up to about 25 times when 25 CPUs used. This technique is very suitable for real-time high spatial resolution CT image reconstruction. (authors)

  9. Clinical application of 64-slice spiral CT in the diagnosis of the Tetralogy of Fallot

    International Nuclear Information System (INIS)

    Wang Ximing; Wu Lebin; Sun Cong; Liu Cheng; Chao, Bao-Ting; Han Bo; Zhang Yunting; Chen Haisong; Li Zhenjia

    2007-01-01

    Objective: To explore the clinical application of 64-slice spiral CT in the diagnosis of the Tetralogy of Fallot. Methods: Eighteen patients with diagnosed Tetralogy of Fallot underwent cardiac CT angiography with 64-slice CT (CTA). Two- and three-dimensional images were used for diagnosing in all cases by means of MPR (coronal, sagital and oblique), cMPR, MIP and VRT. Results: All patients had ventricular septal defect, pulmonary stenosis and hypertrophy of right ventricle. The morphologic features of Tetralogy of Fallot were equal to echocardiography. Patent ductus arteriosus (PDA) were detected on eight patients. Main coronary artery branches and partial sub-branches were visualized in all patients. Abnormal coronary arteries were found in seven cases: both left and right main coronary artery arising from the right aortic sinus one case, right main coronary artery and circumflex (CX) arising from the right aortic sinus one case, left anterior descending (LAD) and CX arising from left aortic sinus directly one case, left and right coronary artery arising from back and front of the aortic sinus, respectively, three cases. Pulmonary artery branch stenosis was found in 12 cases and branch pulmonary artery dilation noticed in 1 case. Double superior vena cava was also found in one case. According to the surgery the diagnostic accuracy of CT and Echocardiography was 95.45 and 83.33%, respectively. Conclusion: Two- and three-dimensional 64-slice CTA not only show the overall anatomical structure of the heart, but also show coronary and pulmonary arteries. With these results, evaluation of coronary anomalies and pulmonary artery stenosis with 64-MSCT is extremely valuable for planning the operative procedure on the patients with Tetralogy of Fallot

  10. Clinical application of 64-slice spiral CT in the diagnosis of the Tetralogy of Fallot

    Energy Technology Data Exchange (ETDEWEB)

    Wang Ximing [Tianjin Medical University, Tianjin City (China) and Shandong Medical Imaging Research Institute, Jinan City, Shandong Province 250021 (China)], E-mail: wxming369@163.com.cn; Wu Lebin [Shandong Medical Imaging Research Institute, Jinan City, Shandong Province 250021 (China); Sun Cong [Shandong Medical Imaging Research Institute, Jinan City, Shandong Province 250021 (China); Shandong University Medical College, Shandong Jinan 250012 (China); Liu Cheng [Shandong Medical Imaging Research Institute, Jinan City, Shandong Province 250021 (China); Chao, Bao-Ting [Shandong University Medical College, Shandong Jinan 250012 (China); Han Bo [Shandong Provincial Hospital Pediatric Department, Shandong, Jinan 250021 (China); Zhang Yunting [Tianjin Medical University, General Hospital MR Department, Tianjin City (China); Chen Haisong [Shandong Medical Imaging Research Institute, Jinan City, Shandong Province 250021 (China); Shandong University Medical College, Shandong Jinan 250012 (China); Li Zhenjia [Shandong Medical Imaging Research Institute, Jinan City, Shandong Province 250021 (China)

    2007-11-15

    Objective: To explore the clinical application of 64-slice spiral CT in the diagnosis of the Tetralogy of Fallot. Methods: Eighteen patients with diagnosed Tetralogy of Fallot underwent cardiac CT angiography with 64-slice CT (CTA). Two- and three-dimensional images were used for diagnosing in all cases by means of MPR (coronal, sagital and oblique), cMPR, MIP and VRT. Results: All patients had ventricular septal defect, pulmonary stenosis and hypertrophy of right ventricle. The morphologic features of Tetralogy of Fallot were equal to echocardiography. Patent ductus arteriosus (PDA) were detected on eight patients. Main coronary artery branches and partial sub-branches were visualized in all patients. Abnormal coronary arteries were found in seven cases: both left and right main coronary artery arising from the right aortic sinus one case, right main coronary artery and circumflex (CX) arising from the right aortic sinus one case, left anterior descending (LAD) and CX arising from left aortic sinus directly one case, left and right coronary artery arising from back and front of the aortic sinus, respectively, three cases. Pulmonary artery branch stenosis was found in 12 cases and branch pulmonary artery dilation noticed in 1 case. Double superior vena cava was also found in one case. According to the surgery the diagnostic accuracy of CT and Echocardiography was 95.45 and 83.33%, respectively. Conclusion: Two- and three-dimensional 64-slice CTA not only show the overall anatomical structure of the heart, but also show coronary and pulmonary arteries. With these results, evaluation of coronary anomalies and pulmonary artery stenosis with 64-MSCT is extremely valuable for planning the operative procedure on the patients with Tetralogy of Fallot.

  11. GPU accelerated CT reconstruction for clinical use: quality driven performance

    Science.gov (United States)

    Vaz, Michael S.; Sneyders, Yuri; McLin, Matthew; Ricker, Alan; Kimpe, Tom

    2007-03-01

    We present performance and quality analysis of GPU accelerated FDK filtered backprojection for cone beam computed tomography (CBCT) reconstruction. Our implementation of the FDK CT reconstruction algorithm does not compromise fidelity at any stage and yields a result that is within 1 HU of a reference C++ implementation. Our streaming implementation is able to perform reconstruction as the images are acquired; it addresses low latency as well as fast throughput, which are key considerations for a "real-time" design. Further, it is scaleable to multiple GPUs for increased performance. The implementation does not place any constraints on image acquisition; it works effectively for arbitrary angular coverage with arbitrary angular spacing. As such, this GPU accelerated CT reconstruction solution may easily be used with scanners that are already deployed. We are able to reconstruct a 512 x 512 x 340 volume from 625 projections, each sized 1024 x 768, in less than 50 seconds. The quoted 50 second timing encompasses the entire reconstruction using bilinear interpolation and includes filtering on the CPU, uploading the filtered projections to the GPU, and also downloading the reconstructed volume from GPU memory to system RAM.

  12. Preoperative CT angiography reduces surgery time in perforator flap reconstruction

    NARCIS (Netherlands)

    Smit, Jeroen M.; Dimopoulou, Angeliki; Liss, Anders G.; Zeebregts, Clark J.; Kildal, Morten; Whitaker, Iain S.; Magnusson, Anders; Acosta, Rafael

    The use of perforator flaps in breast reconstructions has increased considerably in the past decade. A disadvantage of the perforator flap is difficult dissection, which results in a longer procedure. During spring 2006, we introduced CT angiography (CTA) as part of the diagnostic work-up in

  13. Intravenous spiral CT angiography for assessment before orthotopic liver transplantation: Comparison between tomography, MIP, 3-dimensional surface imaging and intraarterial DSA

    International Nuclear Information System (INIS)

    Hidajat, N.; Vogl, T.J.; Moeller, M.; Bechstein, W.O.; Felix, R.

    1996-01-01

    Purpose: To analyse the efficacy of intravenous spiral CT angiography (SCTA) for the evaluation before orthotopic liver transplantation (oLT) compared with DSA. Methods: Spiral CT was performed on 31 potential recipients of a liver graft in order to examine hepatic vessels, coeliac axis, splenic artery and superior mesenteric artery. The arterial vessels were reconstructed in 'Maximum Intensity Projection (MIP)' and 'Shaded Surface Display (SSD)'-technique. The axial images, MIP and SSD were compared in 25 patients with DSA with regard to the visualisation of the vascular anatomy, detectability of stenosis and vascular diameters. Results: The type of arterial liver supply could be determined via SCTA in all patients. Stenosis of the coeliac axis was seen in ten patients on the DSA, MIP and SSD and in eight patients on the axial images. Occlusion of the hepatic artery was clearly visualised in two patients on the DSA, axial images and MIP and in one patient on the SSD. There was no false positive diagnosis with SCTA. SSD was seen as the best technique to visualise the vessels without overshadowing. There were no significant differences between the diamters measured from the axial images, MIP and SSD images in transversal direction and the DSA images (p>0.05). Conclusion: SCTA is a greatly promising method for the imaging of vessels supplying the liver before oLT, and may convey more diagnostic information than DSA. (orig.) [de

  14. Spiral computed tomography-intravenous cholangiography with three-dimensional reconstructions for imaging the biliary tree

    International Nuclear Information System (INIS)

    Alibrahim, E; Gibson, R.N.; Vincent, J; Speer, T.; Collier, N.; Jardine, C.

    2006-01-01

    This study aimed to assess the ability of CT-i.v. cholangiography to show the perihilar biliary and cystic duct anatomy and to assess the relative performance of axial, maximum intensity projection and surface rendered displays. We also assessed the correlation between serum bilirubin levels and adequacy of biliary opacification. Spiral CT was carried out following infusion of 100 mL of Biliscopin in 181 patients with suspected biliary disease. The display of biliary anatomy was of high quality, with 91% of patients having good opacification of at least first-order bile ducts and 84% having good opacification of at least third-order right and left hepatic ducts. The quality of biliary opacification correlated inversely to serum bilirubin levels, with levels above two to three times the normal value being associated with lower rates of good opacification. Maximum intensity projection and surface rendered reformats aided anatomical interpretation to a similar degree. The relative frequency of types of perihilar branching patterns and cystic duct junctional anatomy correlated closely to those reported from previous anatomical studies. Copyright (2006) Blackwell Science Pty Ltd

  15. The experimental study on bowel ischemia in closed loop obstruction by using multi-phase spiral CT

    International Nuclear Information System (INIS)

    Zhang Xiaoming; Yang Hanfeng; Huang Xiaohua; Tang Xianying; Jian Pu; Yang Zhengwei; Zhou Jiyong; Zhao Zongwen

    2005-01-01

    Objective: To evaluate the bowel ischemia in experimental closed loop obstruction by using multi-phase spiral CT. Methods: Twenty-four New Zealand rabbits of both sexes (mean age, 4 months, and mean body weight, 2.5-3.0 kg) were divided randomly into three groups with each group containing 8 rabbits. After clamping 10-15 cm segments of small bowel and their veins for 0.5 hours (Group A), 1-2 hours (Group B), and 3-5 hours (Group C), respectively, multi-phase spiral CT was performed at baseline, and at arterial, venous, and delayed phases after intravenous contrast administration. Then the rabbits were sacrificed to observe their surgical and histological changes. Two radiologists, blinded to the animal model classification and their histological results, individually reviewed the CT images to observe the CT appearances of the closed loop. Statistical significance criteria was determined by P 0.05) at baseline, however, they were significantly different (P<0.05) at all phases after enhancement. Among rabbits without necrotic closed loop, 11 of 13 had continuous enhancement at all phases, while only 1 of 11 rabbits with necrotic closed loop showed continuous enhancement (P<0.05). Conclusion: The ischemia of bowel wall in different phases after clamping small bowel and their veins can be evaluated by using enhanced multi-phase spiral CT. Continuous enhancement of bowel wall in multi-phase spiral CT can be seen prominently in the early bowel ischemia, but necrotic bowel shows no enhancement. (authors)

  16. Effect of the degree of sternal depression on the cardiac rotation in pectus excavatum: evaluation with spiral CT

    International Nuclear Information System (INIS)

    Yu Jianqun; Yang Zhigang; Li Zhenlin; Guo Yingkun; Lu Chunyan; Zhang Mei

    2004-01-01

    Objective: To evaluate the effects of the degree of sternal depression on the cardiac rotation in pectus excavatum by using spiral CT. Methods: Spiral CT features of 32 patients with surgically corrected pectus excavatum were retrospectively reviewed. They included 27 males and 5 females ranging in age from 6 months to 17 years (mean, 6.3 years). Analysis was based on relationship among the degree of sternal depression, CT depression index, cardiac rotation angle, and PV angle. Results: 32 cases of pectus excavatum presented the sternal depression (21 ± 7) mm, CT depression index 2.9 ± 1.8, cardiac rotation angle (55.9 ± 9.8) degree, and PV angle (49.8 ± 14.0) degree, respectively. The sternal depression (17 mm) in cases with CT depression index less than 2.4 was smaller than those with CT depression index 2.4-2.9 (21 mm) and CT depression index larger than 2.9 (27 mm) (F 5.39, P<0.01). Cardiac rotation angle (49.7 degree) in cases with CT depression index less than 2.4 was smaller than those with CT depression index 2.4-2.9 (55.5 degree) and CT depression index larger than 2.9 (66.9 degree) (F=7.44, P<0.01). PV angle (58.7 degree) in cases with CT depression index less than 2.4 was larger than those with CT depression index 2.4-2.9 (46.5 degree) and CT depression index more than 2.9 (42.4 degree) ( F=3.33, P<0.05). Cardiac rotation angle of pectus excavatum had positive correlation with the CT depression index (γ=0.73, P<0.01). Conclusion: Spiral CT is a better tool for revealing chest deformity and corresponding cardiac rotation. The degree of sternal depression in pectus excavatum directly influences the cardiac rotation, and they had positive correlation. (authors)

  17. Split-Bregman-based sparse-view CT reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Vandeghinste, Bert; Vandenberghe, Stefaan [Ghent Univ. (Belgium). Medical Image and Signal Processing (MEDISIP); Goossens, Bart; Pizurica, Aleksandra; Philips, Wilfried [Ghent Univ. (Belgium). Image Processing and Interpretation Research Group (IPI); Beenhouwer, Jan de [Ghent Univ. (Belgium). Medical Image and Signal Processing (MEDISIP); Antwerp Univ., Wilrijk (Belgium). The Vision Lab; Staelens, Steven [Ghent Univ. (Belgium). Medical Image and Signal Processing (MEDISIP); Antwerp Univ., Edegem (Belgium). Molecular Imaging Centre Antwerp

    2011-07-01

    Total variation minimization has been extensively researched for image denoising and sparse view reconstruction. These methods show superior denoising performance for simple images with little texture, but result in texture information loss when applied to more complex images. It could thus be beneficial to use other regularizers within medical imaging. We propose a general regularization method, based on a split-Bregman approach. We show results for this framework combined with a total variation denoising operator, in comparison to ASD-POCS. We show that sparse-view reconstruction and noise regularization is possible. This general method will allow us to investigate other regularizers in the context of regularized CT reconstruction, and decrease the acquisition times in {mu}CT. (orig.)

  18. Morphological and functional diagnosis in the head and neck with multiplanar spiral CT

    International Nuclear Information System (INIS)

    Lell, M.; Baum, U.; Noemayr, A.; Greess, H.; Lenz, M.; Bautz, W.; Koester, M.

    1999-01-01

    Purpose: To evaluate the improvement of multislice-spiral CT in the assessment of head and neck tumors. Material and methods: 80 patients with suspected tumor in the head and neck region were examined with MSCT (Somatom Plus 4 VZ) after the administration of i.v. contrast material. Slice collimation was 4x1 mm with a pitch factor of 6. Additional multiplanar reformations were calculated in each case. Results: The specific anatomy and pathways of tumor spread is difficult to demonstrate in cross-sectional imaging. Tumor infiltration of the base of the skull or the palate could be depicted or excluded on coronal MPR, additional coronal scanning was not necessary. The detection of pathologic lymph nodes was improved with MPR in 7 patients. Discussion: The exact determination of tumor margins is mandatory for modern therapy concepts of limited surgery. High resolution datasets are basis for reformations in arbitrary planes, making additional coronal scanning not necessary. Functional imaging of the larynx and hypopharynx improve the diagnostic accuracy of CT, a short scantime is necessary to reduce motion artifacts. Conclusive assessment of tumor infiltration, lymphatic spread and functional alterations is improved with MSCT. (orig.) [de

  19. Blind deblurring of spiral CT images - comparative studies on edge-to-noise ratios

    International Nuclear Information System (INIS)

    Jiang Ming; Wan Ge; Skinner, Margaret W.; Rubinstein, Jay T.; Vannier, Michael W.

    2002-01-01

    A recently developed blind deblurring algorithm based on the edge-to-noise ratio has been applied to improve the quality of spiral CT images. Since the discrepancy measure used to quantify the edge and noise effects is not symmetric, there are several ways to formulate the edge-to-noise ratio. This article is to investigate the performance of those ratios with phantom and patient data. In the phantom study, it is shown that all the ratios share similar properties, validating the blind deblurring algorithm. The image fidelity improvement varies from 29% to 33% for different ratios, according to the root mean square error (RMSE) criterion; the optimal iteration number determined for each ratio varies from 25 to 35. Those ratios that are associated with most satisfactory performance are singled out for the image fidelity improvement of about 33% in the numerical simulation. After automatic blind deblurring with the selected ratios, the spatial resolution of CT is substantially refined in all the cases tested

  20. Radiation dosimetry and its influencing factors for the multi-detector/slice spiral CT

    International Nuclear Information System (INIS)

    Bai Mei; Zheng Junzheng

    2008-01-01

    The Multi-Detector/Slice Spiral Computed Tomography (MDCT/MSCT)reflects the new progress in equipment and technology for radiology. Its popularized application demonstrates its advantages for clinical diagnosis. With the continuous development and growing uses of the MDCT/MSCT, the medical exposure of the patients and public has also been increasing. Therefore, assessment of the radiation dose and radiation risk from X-CT has become an increasingly important concern that should be addressed. Thus, this paper summarizes the main characteristics of the MDCT/MSCT emphasizing particularly on the radiation dosimetry, and reviews the expressions and measures of radiation dose in the MDCT/MSCT. In addition, main factors that influence radiation dose from the MDCT/MSCT are also discussed. A proper grasp of its radiation dosimetry and assessment method can significantly help radiologists, health physicists, medical physicists, X-CT engineers and manufacturers improve the management of radiation dose while optimizing the image quality in the MDCT/MSCT. (authors)

  1. Filtered backprojection proton CT reconstruction along most likely paths

    Energy Technology Data Exchange (ETDEWEB)

    Rit, Simon; Dedes, George; Freud, Nicolas; Sarrut, David; Letang, Jean Michel [Universite de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Universite Lyon 1, Centre Leon Berard, 69008 Lyon (France)

    2013-03-15

    Purpose: Proton CT (pCT) has the potential to accurately measure the electron density map of tissues at low doses but the spatial resolution is prohibitive if the curved paths of protons in matter is not accounted for. The authors propose to account for an estimate of the most likely path of protons in a filtered backprojection (FBP) reconstruction algorithm. Methods: The energy loss of protons is first binned in several proton radiographs at different distances to the proton source to exploit the depth-dependency of the estimate of the most likely path. This process is named the distance-driven binning. A voxel-specific backprojection is then used to select the adequate radiograph in the distance-driven binning in order to propagate in the pCT image the best achievable spatial resolution in proton radiographs. The improvement in spatial resolution is demonstrated using Monte Carlo simulations of resolution phantoms. Results: The spatial resolution in the distance-driven binning depended on the distance of the objects from the source and was optimal in the binned radiograph corresponding to that distance. The spatial resolution in the reconstructed pCT images decreased with the depth in the scanned object but it was always better than previous FBP algorithms assuming straight line paths. In a water cylinder with 20 cm diameter, the observed range of spatial resolutions was 0.7 - 1.6 mm compared to 1.0 - 2.4 mm at best with a straight line path assumption. The improvement was strongly enhanced in shorter 200 Degree-Sign scans. Conclusions: Improved spatial resolution was obtained in pCT images with filtered backprojection reconstruction using most likely path estimates of protons. The improvement in spatial resolution combined with the practicality of FBP algorithms compared to iterative reconstruction algorithms makes this new algorithm a candidate of choice for clinical pCT.

  2. 3D dictionary learning based iterative cone beam CT reconstruction

    Directory of Open Access Journals (Sweden)

    Ti Bai

    2014-03-01

    Full Text Available Purpose: This work is to develop a 3D dictionary learning based cone beam CT (CBCT reconstruction algorithm on graphic processing units (GPU to improve the quality of sparse-view CBCT reconstruction with high efficiency. Methods: A 3D dictionary containing 256 small volumes (atoms of 3 × 3 × 3 was trained from a large number of blocks extracted from a high quality volume image. On the basis, we utilized cholesky decomposition based orthogonal matching pursuit algorithm to find the sparse representation of each block. To accelerate the time-consuming sparse coding in the 3D case, we implemented the sparse coding in a parallel fashion by taking advantage of the tremendous computational power of GPU. Conjugate gradient least square algorithm was adopted to minimize the data fidelity term. Evaluations are performed based on a head-neck patient case. FDK reconstruction with full dataset of 364 projections is used as the reference. We compared the proposed 3D dictionary learning based method with tight frame (TF by performing reconstructions on a subset data of 121 projections. Results: Compared to TF based CBCT reconstruction that shows good overall performance, our experiments indicated that 3D dictionary learning based CBCT reconstruction is able to recover finer structures, remove more streaking artifacts and also induce less blocky artifacts. Conclusion: 3D dictionary learning based CBCT reconstruction algorithm is able to sense the structural information while suppress the noise, and hence to achieve high quality reconstruction under the case of sparse view. The GPU realization of the whole algorithm offers a significant efficiency enhancement, making this algorithm more feasible for potential clinical application.-------------------------------Cite this article as: Bai T, Yan H, Shi F, Jia X, Lou Y, Xu Q, Jiang S, Mou X. 3D dictionary learning based iterative cone beam CT reconstruction. Int J Cancer Ther Oncol 2014; 2(2:020240. DOI: 10

  3. Three-dimensional helical (spiral) CT angiography. Visualization of vessels in the maxillofacial regions

    International Nuclear Information System (INIS)

    Hanawa, Shigeo; Sakamoto, Hidetomo; Mori, Shin-ichiro; Kagawa, Toyohiro; Seze, Ryosuke; Ishioka, Hisakazu; Tashiro, Himiko; Ogawa, Kazuhisa; Wada, Tadako

    1998-01-01

    Authors performed the contrast helical CT for tumors on the maxillofacial regions, and reconstituted these data into the three-dimensional helical (spiral) CT angiography (CTA). Furthermore the conditions of photographing and the clinical significance of CTA were discussed. The subjects were 24 cases (including 13 of malignant tumors, 4 of benign tumors, 4 of inflammation and 3 of malformations), to which the contrast helical CT was performed transvenously. The photographing condition was set in principal to 140 kV of the tube voltage, 160 (200) mA of the tube current, 3 mm of the X-ray beam width, 3 mm/sec (pitch=1) of the turn-table moving speed. The relationship between the beam width and the pitch was determined by the phantom experiments. The scanning was carried out maximally for continuous 60 sec as the scanning time of a turn/sec. Of all cases, CTA visualized three-dimensionally vessels, but it was hard in the total carotid arteries and the internal-external carotid arteries. Authors analyzed the axial and the multiplanar reconstitution (MPR) images as the two-dimensional display, and the surface rendering (SR), the volume rendering and the maximum intensity projections (MIP) as the three-dimensional display. The axial and MPR image of the facial arteries and the lingual arteries as the branched vessels from the external carotid arteries were recognized easily. By SR, it was easily to understand the anatomical relationship among vessels, gnathic bone and cervical vertebrae, and by MIP sufficiently observe the concentration dependent calcification of the vessel walls. Three-dimensional CTA is very useful to get the three-dimensional visual information about the anatomical structures of the maxillofacial regions which is necessary for oral surgeons to plan the pre-operational strategies. (K.H.)

  4. Double prospectively ECG-triggered high-pitch spiral acquisition for CT coronary angiography: Initial experience

    International Nuclear Information System (INIS)

    Wang, Q.; Qin, J.; He, B.; Zhou, Y.; Yang, J.-J.; Hou, X.-L.; Yang, X.-B.; Chen, J.-H.; Chen, Y.-D.

    2013-01-01

    Aim: To evaluate the feasibility of double prospectively electrocardiogram (ECG)-triggered high-pitch spiral acquisition mode (double high-pitch mode) for coronary computed tomography angiography (CTCA). Materials and methods: One hundred and forty-nine consecutive patients [40 women, 109 men; mean age 58.2 ± 9.2 years; sinus rhythm ≤70 beats/min (bpm) after pre-medication, body weight ≤100 kg] were enrolled for CTCA examinations using a dual-source CT system with 2 × 128 × 0.6 mm collimation, 0.28 s rotation time, and a pitch of 3.4. Double high-pitch mode was prospectively triggered first at 60% and later at 30% of the R–R interval within two cardiac cycles. Image quality was evaluated using a four-point scale (1 = excellent, 4 = non-assessable). Results: From 2085 coronary artery segments, 86.4% (1802/2085) were rated as having a score of 1, 12.3% (257/2085) as score of 2, 1.2% (26/2085) as score of 3, and none were rated as “non-assessable”. The average image quality score was 1.15 ± 0.26 on a per-segment basis. The effective dose was calculated by multiplying the coefficient factor of 0.028 by the dose–length product (DLP); the mean effective dose was 3.5 ± 0.8 mSv (range 1.7–7.6 mSv). The total dosage of contrast medium was 78.7 ± 2.9 ml. Conclusion: Double prospectively ECG-triggered high-pitch spiral acquisition mode provides good image quality with an average effective dose of less than 5 mSv in patients with a heart rate ≤70 bpm

  5. MR appearance of cartilage defects of the knee: preliminary results of a spiral CT arthrography-guided analysis

    International Nuclear Information System (INIS)

    Berg, B.C. vande; Lecouvet, F.E.; Maldague, B.; Malghem, J.

    2004-01-01

    The aim of this study was to determine signal intensity patterns of cartilage defects at MR imaging. The MR imaging (3-mm-thick fat-suppressed intermediate-weighted fast spin-echo images) was obtained in 31 knees (21 male and 10 female patients; mean age 45.5 years) blindly selected from a series of 252 consecutive knees investigated by dual-detector spiral CT arthrography. Two radiologists determined in consensus the MR signal intensity of the cartilage areas where cartilage defects had been demonstrated on the corresponding reformatted CT arthrographic images. There were 83 cartilage defects at spiral CT arthrography. In 52 (63%) lesion areas, the MR signal intensity was higher than that of adjacent normal cartilage with signal intensity equivalent to (n=31) or lower than (n=21) that of articular fluid. The MR signal intensity was equivalent to that of adjacent normal cartilage in 17 (20%) lesion areas and lower than that of adjacent cartilage in 8 (10%) lesion areas. In 6 (7%) lesion areas, mixed low and high signal intensity was observed. The MR signal intensity of cartilage defects demonstrated on spiral CT arthrographic images varies from low to high on fat-suppressed intermediate-weighted fast spin-echo MR images obtained with our equipment and MR parameters. (orig.)

  6. Spectrotemporal CT data acquisition and reconstruction at low dose

    International Nuclear Information System (INIS)

    Clark, Darin P.; Badea, Cristian T.; Lee, Chang-Lung; Kirsch, David G.

    2015-01-01

    Purpose: X-ray computed tomography (CT) is widely used, both clinically and preclinically, for fast, high-resolution anatomic imaging; however, compelling opportunities exist to expand its use in functional imaging applications. For instance, spectral information combined with nanoparticle contrast agents enables quantification of tissue perfusion levels, while temporal information details cardiac and respiratory dynamics. The authors propose and demonstrate a projection acquisition and reconstruction strategy for 5D CT (3D + dual energy + time) which recovers spectral and temporal information without substantially increasing radiation dose or sampling time relative to anatomic imaging protocols. Methods: The authors approach the 5D reconstruction problem within the framework of low-rank and sparse matrix decomposition. Unlike previous work on rank-sparsity constrained CT reconstruction, the authors establish an explicit rank-sparse signal model to describe the spectral and temporal dimensions. The spectral dimension is represented as a well-sampled time and energy averaged image plus regularly undersampled principal components describing the spectral contrast. The temporal dimension is represented as the same time and energy averaged reconstruction plus contiguous, spatially sparse, and irregularly sampled temporal contrast images. Using a nonlinear, image domain filtration approach, the authors refer to as rank-sparse kernel regression, the authors transfer image structure from the well-sampled time and energy averaged reconstruction to the spectral and temporal contrast images. This regularization strategy strictly constrains the reconstruction problem while approximately separating the temporal and spectral dimensions. Separability results in a highly compressed representation for the 5D data in which projections are shared between the temporal and spectral reconstruction subproblems, enabling substantial undersampling. The authors solved the 5D reconstruction

  7. Algorithms of CT value correction for reconstructing a radiotherapy simulation image through axial CT images

    International Nuclear Information System (INIS)

    Ogino, Takashi; Egawa, Sunao

    1991-01-01

    New algorithms of CT value correction for reconstructing a radiotherapy simulation image through axial CT images were developed. One, designated plane weighting method, is to correct CT value in proportion to the position of the beam element passing through the voxel. The other, designated solid weighting method, is to correct CT value in proportion to the length of the beam element passing through the voxel and the volume of voxel. Phantom experiments showed fair spatial resolution in the transverse direction. In the longitudinal direction, however, spatial resolution of under slice thickness could not be obtained. Contrast resolution was equivalent for both methods. In patient studies, the reconstructed radiotherapy simulation image was almost similar in visual perception of the density resolution to a simulation film taken by X-ray simulator. (author)

  8. Reconstruction of CT images by the Bayes- back projection method

    CERN Document Server

    Haruyama, M; Takase, M; Tobita, H

    2002-01-01

    In the course of research on quantitative assay of non-destructive measurement of radioactive waste, the have developed a unique program based on the Bayesian theory for reconstruction of transmission computed tomography (TCT) image. The reconstruction of cross-section images in the CT technology usually employs the Filtered Back Projection method. The new imaging reconstruction program reported here is based on the Bayesian Back Projection method, and it has a function of iterative improvement images by every step of measurement. Namely, this method has the capability of prompt display of a cross-section image corresponding to each angled projection data from every measurement. Hence, it is possible to observe an improved cross-section view by reflecting each projection data in almost real time. From the basic theory of Baysian Back Projection method, it can be not only applied to CT types of 1st, 2nd, and 3rd generation. This reported deals with a reconstruction program of cross-section images in the CT of ...

  9. 3D spiral CT imaging of bone anomalies in a case of diastematomyelia

    International Nuclear Information System (INIS)

    Skalej, Martin; Duffner, Frank; Stefanou, Alexander; Petersen, Dirk

    1999-01-01

    The case of a 48-year-old woman, suffering from a diastematomyelia, is presented. This case and the diagnostic findings are used to demonstrate the demands on imaging methods with respect to a new classification of split cord malformations (SCMs) recently published. Although MRI is the method of choice for imaging of the spinal cord generally, only X-ray methods and especially conventional computer tomography provide the information necessary for correct classification of SCMs. Additional 3D-reconstructions from suitable CT-data are helpful in visualizing complex anomalies of bony structures found in most cases of SCM

  10. Reconstruction of a ring applicator using CT imaging: impact of the reconstruction method and applicator orientation

    International Nuclear Information System (INIS)

    Hellebust, Taran Paulsen; Tanderup, Kari; Bergstrand, Eva Stabell; Knutsen, Bjoern Helge; Roeislien, Jo; Olsen, Dag Rune

    2007-01-01

    The purpose of this study is to investigate whether the method of applicator reconstruction and/or the applicator orientation influence the dose calculation to points around the applicator for brachytherapy of cervical cancer with CT-based treatment planning. A phantom, containing a fixed ring applicator set and six lead pellets representing dose points, was used. The phantom was CT scanned with the ring applicator at four different angles related to the image plane. In each scan the applicator was reconstructed by three methods: (1) direct reconstruction in each image (DR) (2) reconstruction in multiplanar reconstructed images (MPR) and (3) library plans, using pre-defined applicator geometry (LIB). The doses to the lead pellets were calculated. The relative standard deviation (SD) for all reconstruction methods was less than 3.7% in the dose points. The relative SD for the LIB method was significantly lower (p < 0.05) than for the DR and MPR methods for all but two points. All applicator orientations had similar dose calculation reproducibility. Using library plans for applicator reconstruction gives the most reproducible dose calculation. However, with restrictive guidelines for applicator reconstruction the uncertainties for all methods are low compared to other factors influencing the accuracy of brachytherapy

  11. Thin-section CT vs spiral CT in candidates for lung volume reduction surgery: a comparison based on radiologists' subjective preferences

    International Nuclear Information System (INIS)

    Cederlund, K.; Hoegberg, S.; Rasmussen, E.; Svane, B.; Bergstrand, L.

    2001-01-01

    The aim of this study was to investigate whether high-resolution (HRCT) or spiral CT was preferred in evaluating severe emphysema in patients undergoing lung volume reduction surgery (LVRS), whether there is any difference in this regard between the cranial and caudal part of the lung, and whether the degree of emphysema has an impact on the radiologists' preference. The study was performed by letting four radiologists compare images obtained with the two techniques (film pairs) and decide which technique they preferred or if the techniques were considered as equal in evaluating emphysema. In evaluation of 188 film pairs, the HRCT images were preferred in 56 %, spiral CT in 19 % and the techniques considered as equal in 25 %. Spiral CT images were preferred more often in the caudal part of the lung and in more advanced emphysema compared with the HRCT images. The study confirms our clinical assumption that use of both CT techniques are valuable in evaluating advanced emphysema and there may be technical as well as histopathological reasons for this. (orig.)

  12. Thin-section CT vs spiral CT in candidates for lung volume reduction surgery: a comparison based on radiologists' subjective preferences

    Energy Technology Data Exchange (ETDEWEB)

    Cederlund, K.; Hoegberg, S.; Rasmussen, E.; Svane, B. [Dept. of Thoracic Radiology, Karolinska Hospital, Stockholm (Sweden); Bergstrand, L. [Dept. of Radiology, Danderyds Hospital (Sweden)

    2001-03-01

    The aim of this study was to investigate whether high-resolution (HRCT) or spiral CT was preferred in evaluating severe emphysema in patients undergoing lung volume reduction surgery (LVRS), whether there is any difference in this regard between the cranial and caudal part of the lung, and whether the degree of emphysema has an impact on the radiologists' preference. The study was performed by letting four radiologists compare images obtained with the two techniques (film pairs) and decide which technique they preferred or if the techniques were considered as equal in evaluating emphysema. In evaluation of 188 film pairs, the HRCT images were preferred in 56 %, spiral CT in 19 % and the techniques considered as equal in 25 %. Spiral CT images were preferred more often in the caudal part of the lung and in more advanced emphysema compared with the HRCT images. The study confirms our clinical assumption that use of both CT techniques are valuable in evaluating advanced emphysema and there may be technical as well as histopathological reasons for this. (orig.)

  13. Evaluation of aortocoronary bypass graft patency by reconstructed CT image

    International Nuclear Information System (INIS)

    Kawakita, Seizaburo; Koide, Takashi; Saito, Yoshio; Yamamoto, Tadao; Iwasaki, Tadaaki

    1982-01-01

    Ten patients were examined in the period of three months from January to March 1981. The patients were operated from 1 month to 7 years before CT. A bypass to the left anterior descending artery (LAD) was grafted in 10 cases, 2 to the right coronary artery (RCA), 4 to an obtuse marginal artery (OM), and 1 to a diagonal artery. Image reconstruction was performed in 10 cases by using an image analytical computer Evaluskop. Appropriate planes for reconstruction were selected by trial and error methods upon observation of CT images. When gained picture of a graft course coincided with surgical records or angiography, the work of building images was concluded. On cross section, grafts to LAD were visualized in all 10 cases: 9 in the entire course and 1 in a proximal part of the graft. Two to RCA, 4 to OM and 1 to a diagonal were also successfully visualized. Reconstruction of graft images succeeded in 9 grafts of 6 cases. The course of a graft could be pursued from the proximal to the distal end adjacent to the cardiac chamber. The picture of a bypass to LAD was visualized in 6 of 10 grafts. Two bypass to RCA could be depicted, and 1 to OM was also found. However 3 to OM and 1 to a diagonal failed to be visualized throughout their courses in reconstructed images. I think that the causes of faillure mainly depended upon the course of the graft. When a graft was running arc-like surrounding the heart chamber, it was very difficult to depict its entire length in reconstructed images, though the graft could be detected in cross sections. These preliminary studies indicated that reconstruction of CT images had some benefits for the pursuit of graft courses. (J.P.N.)

  14. CT reconstruction technique in lumbar intraneuroforaminal disc herniation

    International Nuclear Information System (INIS)

    Volle, E.; Claussen, C.; Kern, A.; Stoltenburg, G.

    1988-01-01

    The CT appearance of the lumbar neural foramina and contents is described in detail and compared to histopathological specimens. Direct axial scans with secondary sagittal, coronal and paraxial reconstruction series of slices of the neuralforamen were derived from lumbar spine examination of fifty normal adults. These normal parameters were then used to evaluate and subdivide 20 patients with disc herniation involving the neuralforamen. The new paraxial reformation was able to show an intraneuroforaminal disc involvement. CT-reformation technique and operative results in intraneuroforaminal disc herniation correspond in 80%. This improvement in preoperative diagnosis demonstrates to the neurosurgeon the full extent of disc herniation and results in an optimized operative approach. (orig.)

  15. CT reconstruction technique in lumbar intraneuroforaminal disc herniation

    Energy Technology Data Exchange (ETDEWEB)

    Volle, E.; Claussen, C.; Kern, A.; Stoltenburg, G.

    1988-04-01

    The CT appearance of the lumbar neural foramina and contents is described in detail and compared to histopathological specimens. Direct axial scans with secondary sagittal, coronal and paraxial reconstruction series of slices of the neuralforamen were derived from lumbar spine examination of fifty normal adults. These normal parameters were then used to evaluate and subdivide 20 patients with disc herniation involving the neuralforamen. The new paraxial reformation was able to show an intraneuroforaminal disc involvement. CT-reformation technique and operative results in intraneuroforaminal disc herniation correspond in 80%. This improvement in preoperative diagnosis demonstrates to the neurosurgeon the full extent of disc herniation and results in an optimized operative approach.

  16. The comparative study between multi-slice spiral CT angiography and color flow ultrasonography in hepatic and splenic trauma

    International Nuclear Information System (INIS)

    Yan Youxia; Zhang Jin'e; Chen Xiaocong; Cai Shufang

    2007-01-01

    Objective: To investigate the clinical value of multi-slice spiral CT angiography and color flow ultra- sonography in hepatic and splenic trauma. Methods Thirty-six cases of hepatic and splenic trauma were collected, the MSCT were analyzed and compared with that of color flow ultrasonography. Results: Seventeen cases were Hepatic trauma including nine cases of hepatic contusion, six cases of sub-envelope hematoma, two cases of both sub-envelope hematoma and hepatic contusion. Nineteen cases were splenic trauma including nine cases of splenic contusion, ten cases of sub-envelope hematoma. Conclusion: Multi-slice spiral CT angiography show hepatic and splenic trauma clearer than that of color flow ultrasonography, and can provide reliable basis for clinic diagnosis and therapy. (authors)

  17. Evaluation of the nutcracker syndrome using multi-slice spiral CT

    International Nuclear Information System (INIS)

    Shi Heshui; Fan Yanqing; Han Ping; Zhou Chengkai; Zhao Long; Wu Hongying; Yu Qun; Liu Yonghua

    2007-01-01

    Objective: To evaluate the ability of multi-slice spiral CT (MSCT) in diagnosing nutcracker syndrome(NCS). Methods: MSCT angiography (MSCTA) or contrast enhanced CT data of 16 patients clinically diagnosed as NCS( patient group) and 80 subjects with nomal kidneys and renal vessels (control group ) were retrospectively reviewed. The anatomy, course and relationship to the adjacent structure of left renal vein (LRV) and its branches were observed. The angle (a) between SMA and the abdominal aorta (AA), the distance (d) between SMA and AA at the level of LRV passing through, the cross areas of LRV through the angle (s1) and at the largest diameter near the renal hilar (s2) were measured and the ratio(q) of s2 to sl was calculated. Results: All LRVs were compressed and showed dilated, 7 of them with the genesial gland vein enlargement. The causes of the LRV narrowing and obstruction were small angle (a) in 14 patients and abnormal path of LRV posterior to AA in 2 cases. The value of a,d,s1,s2 and q in the patient group and the control group were: (21±4) degree, (0.53±0.11) cm, (0.28±0.06) cm 2 , (1.42±0.48) cm 2 , 5.26 and (52±24) degree, (1.39±0.70) cm, (0.81±0.32) cm 2 , (1.21±0.35) cm 2 , 1.52, respectively. The differences were significant between the two groups (P< 0.05). Conclusion: The appearance and its path of the LRV could be well delineated on the MSCT, allowing a accurate evaluation of the LRV narrowing non-invasively. (authors)

  18. Recurrent pyogenic cholangitis: clinico-pathologic correlation of focal attenuation differences on multi-phasic spiral CT

    International Nuclear Information System (INIS)

    Jeong, Jun Yong; Han, Joon Koo; Kim, Tae Kyoung; Kim, Seog Joon; Kim, Hyun Bum; Choi, Byung Ihn

    2002-01-01

    To determine the clinical and the pathologic significance of the focal attenuation differences (FAD) and bile duct wall enhancement occurring in recurrent pyogenic cholangitis (RPC) and seen at multiphasic spiral CT. Among the multiphasic (non-contrast, arterial and portal or delayed phase) spiral CT findings of 60 consecutive patients, two types of FAD were noted during the non-contrast phase. These were Type A (iso) and Type B (low attenuation), and their distribution pattern (lobar versus patchy, multifocal) and the and the presence or absence of bile duct wall enhancement were recorded. The radiologic findings were correlated with the clinical and pathologic findings. Two types of FAD were noted in 40 of the 60 patients. Active in flammation was present in 19 of the 27 with Type-A and in ten of the 15 in whom the presence of RPC was pathologically proven. Ten of the 13 with Type-B FAD were in a subclinical state, and nine of the ten in whom RPC was pathologically proven had chronic inflammation. Among 20 patients who did not have FAD, RPC was subclinical in 18 and dormant in nine of the eleven in whom its presence was pathologically proven (p<0.001). Clinico-pathologic correlation with bile duct wall enhancement and the distribution pattern of FAD showed no statistical significance. The inflammatory activity of RPC can be predicted by analysis of the FAD seen at multiphasic spiral CT

  19. Assessment of hemodynamics in a rat model of liver cirrhosis with precancerous lesions using multislice spiral CT perfusion imaging.

    Science.gov (United States)

    Ma, Guolin; Bai, Rongjie; Jiang, Huijie; Hao, Xuejia; Ling, Zaisheng; Li, Kefeng

    2013-01-01

    To develop an optimal scanning protocol for multislice spiral CT perfusion (CTP) imaging to evaluate hemodynamic changes in liver cirrhosis with diethylnitrosamine- (DEN-) induced precancerous lesions. Male Wistar rats were randomly divided into the control group (n = 80) and the precancerous liver cirrhosis group (n = 40). The control group received saline injection and the liver cirrhosis group received 50 mg/kg DEN i.p. twice a week for 12 weeks. All animals underwent plain CT scanning, CTP, and contrast-enhanced CT scanning. Scanning parameters were optimized by adjusting the diatrizoate concentration, the flow rate, and the delivery time. The hemodynamics of both groups was further compared using optimized multislice spiral CTP imaging. High-quality CTP images were obtained with following parameters: 150 kV; 150 mAs; 5 mm thickness, 5 mm interval; pitch, 1; matrix, 512 × 512; and FOV, 9.6 cm. Compared to the control group, the liver cirrhosis group had a significantly increased value of the hepatic arterial fraction and the hepatic artery perfusion (P spiral CTP imaging can be used to evaluate the hemodynamic changes in the rat model of liver cirrhosis with precancerous lesions.

  20. Spiral CT aortography: an efficient technique for the diagnosis of traumatic aortic injury

    International Nuclear Information System (INIS)

    Wicky, S.; Capasso, P.; Meuli, R.; Schnyder, P.; Fischer, A.; Segesser, L. von

    1998-01-01

    The objective of this study was to assess the efficiency of spiral CT (SCT) aortography for diagnosing acute aortic lesions in blunt thoracic trauma patients. Between October 1992 and June 1997, 487 SCT scans of the chest were performed on blunt thoracic trauma patients. To assess aortic injury, the following SCT criteria were considered: hemomediastinum, peri-aortic hematoma, irregular aspect of the aortic wall, aortic pseudodiverticulum, intimal flap and traumatic dissection. Aortic injury was diagnosed on 14 SCT examinations (2.9 %), five of the patients having had an additional digital aortography that confirmed the aortic trauma. Twelve subjects underwent surgical repair of the thoracic aorta, which in all but one case confirmed the aortic injury. Two patients died before surgery from severe brain lesions. The aortic blunt lesions were confirmed at autopsy. According to the follow-up of the other 473 patients, we are aware of no false-negative SCT examination. Our limited series shows a sensitivity of 100 % and specificity of 99.8 % of SCT aortography in the diagnosis of aortic injury. It is concluded that SCT aortagraphy is an accurate diagnostic method for the assessment of aortic injury in blunt thoracic trauma patients. (orig.)

  1. Primary research on direct multi-slice spiral CT venography in inferior vena cava

    International Nuclear Information System (INIS)

    Gong Peiyou; Liu Fengli; Ma Xianying; Zhao Li; Wang Liping; Li Xuehua; Li Jian

    2010-01-01

    Objective: To investigate the superiority of direct multi-slice spiral CT venography in inferior vena cava. Methods: Twenty-eight patients performed MSCT venography in inferior vena cava, including 2 cases with both indirect and direct venography, 10 cases with indirect venography, 20 cases with direct venography through unilateral or bilateral lower extremity venous injection. The image quality and enhancement degree of the inferior vena cava were compared in double-blind method. Results: Of 10 cases with indirect venography of inferior vena cava, 1 case was failed due to mild enhancement in inferior vena cava. Image quality was good in 2 cases, poor in 7 cases, no excellent case. Of 20 cases with direct venography of inferior vena cava, the enhancement degree was scored 1, 2 degree in 16, 4 cases respectively and no case was scored 3 degree, the image quality was excellent, good in 16, 4 cases and no case was bad. The success rate was 100%. Conclusion: The image quality of direct MSCT venography in inferior vena cava is better than that of indirect method. (authors)

  2. The Role of Multi-slice Spiral CT Angiography in Patient Management After Endovascular Therapy

    International Nuclear Information System (INIS)

    Peloschek, P.; Sailer, J.; Loewe, C.; Schillinger, M.; Lammer, J.

    2006-01-01

    Objectives. To bring out the role of multi-slice spiral CT angiography (MS-CTA) in patient management after endovascular therapy of subclavian artery stenosis. Methods. Twenty-one consecutive patients with clinically suspected restenosis after endovascular treatment of subclavian artery stenosis or occlusion were included in the study. Eleven patients had been treated with percutaneous transluminal angioplasty (PTA) alone and 10 with PTA and stenting. The mean follow-up period after PTA or stenting was 57 (±27 SD) months. CTA was performed using a bolus-triggered high-resolution protocol with biphasic intravenous contrast medium injection. Axial images and curved planar reformations (CPRs) were rated by three readers with regard to patency of supra-aortic vessels. Imaging findings were correlated with a standardized clinical assessment. Results. All examinations were of diagnostic quality. Of 21 referred patients, 7 had significant reobstruction of the treated subclavian artery. Six of the 7 patients with significant restenosis on CTA were treated conservatively (antiplatelet agents), despite 2 of them being symptomatic on the standardized clinical assessment, which showed a sensitivity and specificity of 86% in predicting stenosis. One patient was treated with PTA and stent deployment because of strong subjective suffering. Conclusion. MS-CTA is useful for exclusion or quantification of clinically suspected restenosis in carefully selected patients after endovascular therapy where ultrasound is inconclusive and/or contrast-enhanced magnetic resonance angiography is contraindicated

  3. Dose reduction in subsecond multislice spiral CT examination of children by online tube current modulation

    International Nuclear Information System (INIS)

    Greess, H.; Lutze, J.; Noemayr, A.; Bautz, W.; Wolf, H.; Hothorn, T.; Kalender, W.A.

    2004-01-01

    The potential of online tube current modulation in subsecond multislice spiral CT (MSCT) examinations of children to reduce the dose without a loss in image quality is investigated in a controlled patient study. The dose can be reduced for oval patient sectional view without an increase in noise if the tube current is reduced where the patient diameter and, consequently, attenuation are small. We investigated a product version of an online control for tube current in a SOMATOM Sensation 4 (Siemens, Forchheim). We evaluated image quality, noise and dose reduction for examinations with online tube current modulation in 30 MSCT of thorax/abdomen and abdomen and compared mA s for tube current modulation to the mA s in standard weight-adapted children protocols. Image quality was rated as ''very good,'' ''good,'' ''diagnostic'' and ''poor'' in a consensus by three radiologists. Noise was assessed in comparison to 24 MSCT examinations without tube current modulation measured as SD in ROIs. The dose was reduced from 26 to 43% (mean 36%), depending on the patient's geometry and weight. (orig.)

  4. Tensor-Based Dictionary Learning for Spectral CT Reconstruction.

    Science.gov (United States)

    Zhang, Yanbo; Mou, Xuanqin; Wang, Ge; Yu, Hengyong

    2017-01-01

    Spectral computed tomography (CT) produces an energy-discriminative attenuation map of an object, extending a conventional image volume with a spectral dimension. In spectral CT, an image can be sparsely represented in each of multiple energy channels, and are highly correlated among energy channels. According to this characteristics, we propose a tensor-based dictionary learning method for spectral CT reconstruction. In our method, tensor patches are extracted from an image tensor, which is reconstructed using the filtered backprojection (FBP), to form a training dataset. With the Candecomp/Parafac decomposition, a tensor-based dictionary is trained, in which each atom is a rank-one tensor. Then, the trained dictionary is used to sparsely represent image tensor patches during an iterative reconstruction process, and the alternating minimization scheme is adapted for optimization. The effectiveness of our proposed method is validated with both numerically simulated and real preclinical mouse datasets. The results demonstrate that the proposed tensor-based method generally produces superior image quality, and leads to more accurate material decomposition than the currently popular popular methods.

  5. Tensor-based Dictionary Learning for Spectral CT Reconstruction

    Science.gov (United States)

    Zhang, Yanbo; Wang, Ge

    2016-01-01

    Spectral computed tomography (CT) produces an energy-discriminative attenuation map of an object, extending a conventional image volume with a spectral dimension. In spectral CT, an image can be sparsely represented in each of multiple energy channels, and are highly correlated among energy channels. According to this characteristics, we propose a tensor-based dictionary learning method for spectral CT reconstruction. In our method, tensor patches are extracted from an image tensor, which is reconstructed using the filtered backprojection (FBP), to form a training dataset. With the Candecomp/Parafac decomposition, a tensor-based dictionary is trained, in which each atom is a rank-one tensor. Then, the trained dictionary is used to sparsely represent image tensor patches during an iterative reconstruction process, and the alternating minimization scheme is adapted for optimization. The effectiveness of our proposed method is validated with both numerically simulated and real preclinical mouse datasets. The results demonstrate that the proposed tensor-based method generally produces superior image quality, and leads to more accurate material decomposition than the currently popular popular methods. PMID:27541628

  6. Prevalence of emphysematous changes as shown by low-dose spiral CT screening images in 6144 healthy subjects

    International Nuclear Information System (INIS)

    Nawa, Takeshi

    2002-01-01

    We assessed the prevalence of emphysematous changes among healthy workers and retired persons, using subjective evaluations of low-dose spiral CT images obtained during thoracic CT screenings for lung cancer. Among 6144 male participants (50-69 years old; mean age, 57), we detected 686 cases (11.2%) with emphysematous changes. The majority (95.3%) of CT-detected emphysema cases were in current or former smokers, and 169 cases (24.6%) showed significant obstructive impairment. Of 236 cases with emphysematous changes in the internal region (more than 20 mm from the costal margin), 98 (41.5%) had significant obstructive impairment. Smoking was found to be the major risk factor for CT-detected emphysema. Longitudinal observation of the emphysema cases, as well as health care support for cessation of smoking, is very important. (author)

  7. Towards an inline reconstruction architecture for micro-CT systems

    International Nuclear Information System (INIS)

    Brasse, David; Humbert, Bernard; Mathelin, Carole; Rio, Marie-Christine; Guyonnet, Jean-Louis

    2005-01-01

    Recent developments in micro-CT have revolutionized the ability to examine in vivo living experimental animal models such as mouse with a spatial resolution less than 50 μm. The main requirements of in vivo imaging for biological researchers are a good spatial resolution, a low dose induced to the animal during the full examination and a reduced acquisition and reconstruction time for screening purposes. We introduce inline acquisition and reconstruction architecture to obtain in real time the 3D attenuation map of the animal fulfilling the three previous requirements. The micro-CT system is based on commercially available x-ray detector and micro-focus x-ray source. The reconstruction architecture is based on a cluster of PCs where a dedicated communication scheme combining serial and parallel treatments is implemented. In order to obtain high performance transmission rate between the detector and the reconstruction architecture, a dedicated data acquisition system is also developed. With the proposed solution, the time required to filter and backproject a projection of 2048 x 2048 pixels inside a volume of 140 mega voxels using the Feldkamp algorithm is similar to 500 ms, the time needed to acquire the same projection

  8. Gamma regularization based reconstruction for low dose CT

    International Nuclear Information System (INIS)

    Zhang, Junfeng; Chen, Yang; Hu, Yining; Luo, Limin; Shu, Huazhong; Li, Bicao; Liu, Jin; Coatrieux, Jean-Louis

    2015-01-01

    Reducing the radiation in computerized tomography is today a major concern in radiology. Low dose computerized tomography (LDCT) offers a sound way to deal with this problem. However, more severe noise in the reconstructed CT images is observed under low dose scan protocols (e.g. lowered tube current or voltage values). In this paper we propose a Gamma regularization based algorithm for LDCT image reconstruction. This solution is flexible and provides a good balance between the regularizations based on l 0 -norm and l 1 -norm. We evaluate the proposed approach using the projection data from simulated phantoms and scanned Catphan phantoms. Qualitative and quantitative results show that the Gamma regularization based reconstruction can perform better in both edge-preserving and noise suppression when compared with other norms. (paper)

  9. To evaluate vascular complications of transplant kidney examined by multislice spiral CT angiograph

    International Nuclear Information System (INIS)

    Peng Qian; Fan Miao; Luo Xiaomei

    2008-01-01

    Objective: To evaluate the value of multislice CT angiography (MSCTA) in vascular complications of transplant kidney. Methods: Six transplant kidneys were undergone enhanced MSCT scanning postoperation. MPR, CPR, VR and VP reformation were performed to observe transplant kidney's parenchyma, renal artery, and renal vein. To analysis all the reconstruction technique and find the advantage and shortage of them. Results: One case showed enhanced function of transplant kidney decreased. Vascular stenosis was found in one case and false aneurysm was found in another transplant kidney. Transplant kidney were enhanced normal in the left three cases. MPR couldn't reconstruct all the tortuous vessel of renal hilus in one plane. But all six cases could expose the vessel of renal hilus very clearly in coronal section and sagittal plane of CPR. Six cases of VR could observe the vessel direction and lesions outside vessel through rotate the reconstruction image. VP could see through inside the vessel of transplant kidney. Conclusion: MSCTA has an important role as an imaging technique to evaluate vascular complications of transplant kidney, it can replace DSA. (authors)

  10. Screenings of lung cancer with low dose spiral CT: results of a three year pilot study and design of the randomised controlled trial Italung-CT

    International Nuclear Information System (INIS)

    Picozzi, Giulia; Paci, Enrico; Lopes Pegna, Andrea

    2005-01-01

    Purpose: To report the results of a three-year observational pilot study of lung cancer screening with low dose computed tomography (CT) and to present the study design of a randomised clinical trial named as Italung CT. Materials and methods: Sixty (47 males and 13 females, mean age 64±4.5 years) heavy smokers (at least 20 packs-year) underwent three low-dose spiral CT screening tests one year apart on a single slice or multislice CT scanner. Indeterminate nodules were managed according to the recommendations of the Early Lung Cancer Action Project. Results: Indeterminate nodules were observed in 33 (55%) of the subjects (60% at the baseline screening test, 24% at the first annual test and 16% at the second annual test). The size of the largest indeterminate nodule was [it

  11. Experimental validation of incomplete data CT image reconstruction techniques

    International Nuclear Information System (INIS)

    Eberhard, J.W.; Hsiao, M.L.; Tam, K.C.

    1989-01-01

    X-ray CT inspection of large metal parts is often limited by x-ray penetration problems along many of the ray paths required for a complete CT data set. In addition, because of the complex geometry of many industrial parts, manipulation difficulties often prevent scanning over some range of angles. CT images reconstructed from these incomplete data sets contain a variety of artifacts which limit their usefulness in part quality determination. Over the past several years, the authors' company has developed 2 new methods of incorporating a priori information about the parts under inspection to significantly improve incomplete data CT image quality. This work reviews the methods which were developed and presents experimental results which confirm the effectiveness of the techniques. The new methods for dealing with incomplete CT data sets rely on a priori information from part blueprints (in electronic form), outer boundary information from touch sensors, estimates of part outer boundaries from available x-ray data, and linear x-ray attenuation coefficients of the part. The two methods make use of this information in different fashions. The relative performance of the two methods in detecting various flaw types is compared. Methods for accurately registering a priori information with x-ray data are also described. These results are critical to a new industrial x-ray inspection cell built for inspection of large aircraft engine parts

  12. Optimization of hybrid iterative reconstruction level in pediatric body CT.

    Science.gov (United States)

    Karmazyn, Boaz; Liang, Yun; Ai, Huisi; Eckert, George J; Cohen, Mervyn D; Wanner, Matthew R; Jennings, S Gregory

    2014-02-01

    The objective of our study was to attempt to optimize the level of hybrid iterative reconstruction (HIR) in pediatric body CT. One hundred consecutive chest or abdominal CT examinations were selected. For each examination, six series were obtained: one filtered back projection (FBP) and five HIR series (iDose(4)) levels 2-6. Two pediatric radiologists, blinded to noise measurements, independently chose the optimal HIR level and then rated series quality. We measured CT number (mean in Hounsfield units) and noise (SD in Hounsfield units) changes by placing regions of interest in the liver, muscles, subcutaneous fat, and aorta. A mixed-model analysis-of-variance test was used to analyze correlation of noise reduction with the optimal HIR level compared with baseline FBP noise. One hundred CT examinations were performed of 88 patients (52 females and 36 males) with a mean age of 8.5 years (range, 19 days-18 years); 12 patients had both chest and abdominal CT studies. Radiologists agreed to within one level of HIR in 92 of 100 studies. The mean quality rating was significantly higher for HIR than FBP (3.6 vs 3.3, respectively; p optimal HIR level was used (p optimal for most studies. The optimal HIR level was less effective in reducing liver noise in children with lower baseline noise.

  13. Reconstructed coronal views of CT and isotopic images of the pancreas

    International Nuclear Information System (INIS)

    Kasuga, Toshio; Kobayashi, Toshio; Nakanishi, Fumiko

    1980-01-01

    To compare functional images of the pancreas by scintigraphy with morphological views of the pancreas by CT, CT coronal views of the pancreas were reconstructed. As CT coronal views were reconstructed from the routine scanning, there was a problem in longitudinal spatial resolution. However, almost satisfactory total images of the pancreas were obtained by improving images adequately. In 27 patients whose diseases had been confirmed, it was easy to compare pancreatic scintigrams with pancreatic CT images by using reconstructed CT coronal views, and information which had not been obtained by original CT images could be obtained by using reconstructed CT coronal views. Especially, defects on pancreatic images and the shape of pancreas which had not been visualized clearly by scintigraphy alone could be visualized by using reconstructed CT coronal views of the pancreas. (Tsunoda, M.)

  14. CT stereotactic reconstruction of oral cavity interstitial plastic tube implants

    International Nuclear Information System (INIS)

    Crispin, V.; Carrasco, P.; Guardino, C.; Lopez, J.; Chust, M.; Arribas, L.; Mengual, J.; Miragall, E.G.; Hernandez, A.; Carrascosa, M.; Cardenal, R.; Guinot, J.; Casana, M.; Prats, C.

    1996-01-01

    The continuous using of CT images in external RT have made us think of its applications for plastic tube interstitial implants in the oral cavity in order to calculate the dose delivered by an interstitial implant at any point of the image and its relationship with local control and complications. Moreover, the outcoming result of the whole treatment depends on whether the irradiated volume up to a prescribed dose includes the CTV or not. None of these objectives may be achieved through the classical film reconstruction. Although film reconstruction appeared as the only accurate method for these purposes in the early eighties, it does not allow us to calculate doses at critical points or volumes. Therefore possible complications over critical tissues surrounding the radioactive implant cannot be taken into account in a precise way. The use of a stereotactic coordinate system could make CT reconstruction as precise as film reconstruction. As our stereotactic frame can be placed over the patient in 'direct' or 'inverse' positions it is really interesting in the applications we are talking about. We also have used a non invasive standard plexiglass helmet commonly used in stereotactic fractionated irradiations in teletherapy. It fits perfectly the patient's head and avoids any movement of the patient during the CT exam. We do parallel slices, approximately perpendicular to the iridium wires (following the Paris System), covering the whole implant helping ourselves with both bone and implant references. The dose-volume histograms and DNR (dose nonuniformity ratio) index defined by Saw et Al are used for intercomparison between the ortogonal and the stereotactic reconstructions. The existence of a minimum in the DNR curve indicates that there is a reference dose rate for this implant which provides an optimal dose distribution. If we calculate which is the minimum of each method, we find they are very close. So, as both methods give very similar results, we can conclude

  15. Dual source multidetector CT-angiography before transcatheter aortic valve implantation (TAVI) using a high-pitch spiral acquisition mode

    Energy Technology Data Exchange (ETDEWEB)

    Wuest, W.; Anders, K.; May, M.S.; Uder, M. [University of Erlangen, Department of Radiology, Erlangen (Germany); Schuhbaeck, A.; Gauss, S.; Marwan, M.; Arnold, M.; Muschiol, G.; Daniel, W.G.; Achenbach, S. [University of Erlangen, Department of Cardiology, Erlangen (Germany); Ensminger, S. [University of Erlangen, Department of Cardiac Surgery, Erlangen (Germany)

    2012-01-15

    Transcatheter Aortic Valve Implantation (TAVI) is an alternative to surgical valve replacement in high risk patients. Angiography of the aortic root, aorta and iliac arteries is required to select suitable candidates, but contrast agents can be harmful due to impaired renal function. We evaluated ECG-triggered high-pitch spiral dual source Computed Tomography (CT) with minimized volume of contrast agent to assess aortic root anatomy and vascular access. 42 patients (82 {+-} 6 years) scheduled for TAVI underwent dual source (DS) CT angiography (CTA) of the aorta using a prospectively ECG-triggered high-pitch spiral mode (pitch = 3.4) with 40 mL iodinated contrast agent. We analyzed aortic root/iliac dimensions, attenuation, contrast to noise ratio (CNR), image noise and radiation exposure. Aortic root/iliac dimensions and distance of coronary ostia from the annulus could be determined in all cases. Mean aortic and iliac artery attenuation was 320 {+-} 70 HU and 340 {+-} 77 HU. Aortic/iliac CNR was 21.7 {+-} 6.8 HU and 14.5 {+-} 5.4 HU using 100 kV (18.8 {+-} 4.1 HU and 8.7 {+-} 2.6 HU using 120 kV). Mean effective dose was 4.5 {+-} 1.2 mSv. High-pitch spiral DSCTA can be used to assess the entire aorta and iliac arteries in TAVI candidates with a low volume of contrast agent while preserving diagnostic image quality. (orig.)

  16. Blockwise conjugate gradient methods for image reconstruction in volumetric CT.

    Science.gov (United States)

    Qiu, W; Titley-Peloquin, D; Soleimani, M

    2012-11-01

    Cone beam computed tomography (CBCT) enables volumetric image reconstruction from 2D projection data and plays an important role in image guided radiation therapy (IGRT). Filtered back projection is still the most frequently used algorithm in applications. The algorithm discretizes the scanning process (forward projection) into a system of linear equations, which must then be solved to recover images from measured projection data. The conjugate gradients (CG) algorithm and its variants can be used to solve (possibly regularized) linear systems of equations Ax=b and linear least squares problems minx∥b-Ax∥2, especially when the matrix A is very large and sparse. Their applications can be found in a general CT context, but in tomography problems (e.g. CBCT reconstruction) they have not widely been used. Hence, CBCT reconstruction using the CG-type algorithm LSQR was implemented and studied in this paper. In CBCT reconstruction, the main computational challenge is that the matrix A usually is very large, and storing it in full requires an amount of memory well beyond the reach of commodity computers. Because of these memory capacity constraints, only a small fraction of the weighting matrix A is typically used, leading to a poor reconstruction. In this paper, to overcome this difficulty, the matrix A is partitioned and stored blockwise, and blockwise matrix-vector multiplications are implemented within LSQR. This implementation allows us to use the full weighting matrix A for CBCT reconstruction without further enhancing computer standards. Tikhonov regularization can also be implemented in this fashion, and can produce significant improvement in the reconstructed images. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  17. A temporal interpolation approach for dynamic reconstruction in perfusion CT

    International Nuclear Information System (INIS)

    Montes, Pau; Lauritsch, Guenter

    2007-01-01

    This article presents a dynamic CT reconstruction algorithm for objects with time dependent attenuation coefficient. Projection data acquired over several rotations are interpreted as samples of a continuous signal. Based on this idea, a temporal interpolation approach is proposed which provides the maximum temporal resolution for a given rotational speed of the CT scanner. Interpolation is performed using polynomial splines. The algorithm can be adapted to slow signals, reducing the amount of data acquired and the computational cost. A theoretical analysis of the approximations made by the algorithm is provided. In simulation studies, the temporal interpolation approach is compared with three other dynamic reconstruction algorithms based on linear regression, linear interpolation, and generalized Parker weighting. The presented algorithm exhibits the highest temporal resolution for a given sampling interval. Hence, our approach needs less input data to achieve a certain quality in the reconstruction than the other algorithms discussed or, equivalently, less x-ray exposure and computational complexity. The proposed algorithm additionally allows the possibility of using slow rotating scanners for perfusion imaging purposes

  18. Automatic detection of pulmonary nodules at spiral CT: clinical application of a computer-aided diagnosis system

    International Nuclear Information System (INIS)

    Wormanns, Dag; Fiebich, Martin; Saidi, Mustafa; Diederich, Stefan; Heindel, Walter

    2002-01-01

    The aim of this study was to evaluate a computer-aided diagnosis (CAD) workstation with automatic detection of pulmonary nodules at low-dose spiral CT in a clinical setting for early detection of lung cancer. Eighty-eight consecutive spiral-CT examinations were reported by two radiologists in consensus. All examinations were reviewed using a CAD workstation with a self-developed algorithm for automatic detection of pulmonary nodules. The algorithm is designed to detect nodules with diameters of at least 5 mm. A total of 153 nodules were detected with at least one modality (radiologists in consensus, CAD, 85 nodules with diameter <5 mm, 68 with diameter ≥5 mm). The results of automatic nodule detection were compared to nodules detected with any modality as gold standard. Computer-aided diagnosis correctly identified 26 of 59 (38%) nodules with diameters ≥5 mm detected by visual assessment by the radiologists; of these, CAD detected 44% (24 of 54) nodules without pleural contact. In addition, 12 nodules ≥5 mm were detected which were not mentioned in the radiologist's report but represented real nodules. Sensitivity for detection of nodules ≥5 mm was 85% (58 of 68) for radiologists and 38% (26 of 68) for CAD. There were 5.8±3.6 false-positive results of CAD per CT study. Computer-aided diagnosis improves detection of pulmonary nodules at spiral CT and is a valuable second opinion in a clinical setting for lung cancer screening despite of its still limited sensitivity. (orig.)

  19. Clinical application of three-dimensional spiral CT cerebral angiography with volume rendering

    International Nuclear Information System (INIS)

    Duan Shaoyin; Huang Xi'en; Kang Jianghe; Zhang Dantong; Lin Qingchi; Cai Guoxiang; Xu Meixin; Pang Ruilin

    2002-01-01

    Objective: To study the methodology and assess the clinical value of three-dimensional CT angiography (3D-CTA) with volume rendering (VR) in cerebral vessels. Methods: Sixty-two patients were examined by means of 3D-CTA with volume rendering. VR was used in the reconstruction of 3D images, and the demonstration of normal vessels and vascular lesions were particularly analyzed. At the same time, comparisons were made between the images of VR and SSD, MIP, and also between the diagnosis of VR-CTA and DSA or postoperative results. Results: In VR images, cerebral vessel routes and vessel cavities were showed clearly, while the relationship among vascular lesions, surrounding vessels, and neighboring structure was distinguished. 50 cases (80.6%) were found positive, 48 of which were correct and 2 were false-positive compared with DSA or postoperative results. The accurate rate of diagnosis was 96.0%. There was no obvious difference in showing the cerebral vessel among the images of VR, SSD and MIP (P > 0.25). Conclusion: Three-dimensional CT cerebral angiography with VR is a new noninvasive effective method. It can even partly replace the DSA. The 3D-images have the characteristics of showing the cerebral vascular cavity and overlapped vessels without cutting the skull

  20. The value of multislice spiral CT in the pre-operative diagnosis of cleft palate

    International Nuclear Information System (INIS)

    Tang Guangxi; Sun Lianfen; Zhang Xiaolin; Yu Chengxin; Lu Ji; Wang Xiaopeng; Li Liya; Yang Cheng; Wang Jun; Tian Yiqing

    2004-01-01

    Objective: To evaluate the practical value of multislice spiral CT (MSCT) in the preoperative diagnosis of cleft palate. Methods: Twenty patients with cleft palate were examined by using thin-slice (1.25 mm/4i) axial MSCT scanning and CT virtual endoscope (CTVE) imaging before and after operations. The cleft of each lesion was measured in the primary axial images. Results: Of the 20 cases, soft-and-hard cleft palate (grade II) was detected in 10 cases, with the clefts of soft palate between 1.5 cm and 2.2 cm, and the clefts of soft-and-hard palate between 1.2 cm and 2.0 cm. The right utter cleft palates were found in 3 cases with the clefts of soft palate between 2.0 cm and 2.5 cm, the clefts of soft-and-hard palate between 2.0 cm and 2.4 cm, and the clefts of hard palate between 1.8 cm and 2.2 cm. The left utter cleft palates (grade III) were found in 5 cases with the clefts of soft palate between 1.2 cm and 1.8 cm, the clefts of soft-and-hard palate between 0.9 cm and 2.0 cm, and the clefts of hard palate between 0.9 cm and 1.8 cm. The bilateral utter cleft palates (grade III) were detected in 2 cases with the clefts of soft palate between 2.1 cm and 2.3 cm, the clefts of soft-and-hard palate between 1.8 cm and 2.0 cm, and the clefts of hard palate between 1.9 cm and 2.3 cm. Conclusion: MSCT could excellently display the shape of all lesions before operation, especially the splitting degree of hard cleft palates in the axial images. Accurate measurements could be done for the cleft of different lesions in MSCT images. CTVE could clearly and directly show the shape of the lesion's interior surface. The pre-operative and post-operative images of each case could be perfectly compared by the combination of MSCT and CTVE

  1. Evaluation of right coronary anomalous origin with mulpi-slice spiral CT

    International Nuclear Information System (INIS)

    Shi Heshui; Han Ping; Kong Xiangquan; Feng Hansheng; Brambs, H.-J.; Hoffmann, M.H.K.

    2006-01-01

    Objective: To evaluate the role of 16-slice spiral computed tomography angiography (MSCTA) to identify the anomalous origin and anatomic course of the right coronary artery (RCA) with conventional X-ray coronary angiography (CAG) serving as standard of reference. Methods: MSCTA data in 8 patients with anomalous RCA were retrospectively analyzed for the study, 7 of them had also undergone CAG examinations. MSCTA and CAG images were analyzed in blinded fashion for accuracy of anomalous artery origin and path detection. Results were compared in a secondary consensus evaluation. Virtual endoscopy (VE) was used to evaluate the orifice of the anomalous arteries and its relationship with the adjacent ostia of normal arteries. Multi-planar reconstruction (MPR), curved MPR, thin-slab maximum intensity projection (MIP), volume rendering (VR) or slab VR (cut-plane VR) were used to assess the aberrant path of the RCA and its relationship with the adjacent large vessels. At least two views of the RCA were analyzed on CAG. Results: The anomalous RCA for all 8 patients were correctly displayed on MSCTA. RCA originated from the left sinus of Valsalva in 6 patients, one RCA from the end of left main coronary artery, another RCA arose from the posterior sinus of Valsalva. The anomalous ostia showed no stenosis. All of them passed between the aortic root and the pulmonary artery. For 7 patients with CAG alone correct identification of the abnormality was achieved in only 71%. Conclusion: MSCTA was superior to show the anomalous orifice and path of the RCA, it should be considered as a prime non-invasive imaging tool for suspected coronary anomalies. (authors)

  2. Simultaneous multislice magnetic resonance fingerprinting (SMS-MRF) with direct-spiral slice-GRAPPA (ds-SG) reconstruction.

    Science.gov (United States)

    Ye, Huihui; Cauley, Stephen F; Gagoski, Borjan; Bilgic, Berkin; Ma, Dan; Jiang, Yun; Du, Yiping P; Griswold, Mark A; Wald, Lawrence L; Setsompop, Kawin

    2017-05-01

    To develop a reconstruction method to improve SMS-MRF, in which slice acceleration is used in conjunction with highly undersampled in-plane acceleration to speed up MRF acquisition. In this work two methods are employed to efficiently perform the simultaneous multislice magnetic resonance fingerprinting (SMS-MRF) data acquisition and the direct-spiral slice-GRAPPA (ds-SG) reconstruction. First, the lengthy training data acquisition is shortened by employing the through-time/through-k-space approach, in which similar k-space locations within and across spiral interleaves are grouped and are associated with a single set of kernel. Second, inversion recovery preparation (IR prepped), variable flip angle (FA), and repetition time (TR) are used for the acquisition of the training data, to increase signal variation and to improve the conditioning of the kernel fitting. The grouping of k-space locations enables a large reduction in the number of kernels required, and the IR-prepped training data with variable FA and TR provide improved ds-SG kernels and reconstruction performance. With direct-spiral slice-GRAPPA, tissue parameter maps comparable to that of conventional MRF were obtained at multiband (MB) = 3 acceleration using t-blipped SMS-MRF acquisition with 32-channel head coil at 3 Tesla (T). The proposed reconstruction scheme allows MB = 3 accelerated SMS-MRF imaging with high-quality T 1 , T 2 , and off-resonance maps, and can be used to significantly shorten MRF acquisition and aid in its adoption in neuro-scientific and clinical settings. Magn Reson Med 77:1966-1974, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  3. 1024 matrix image reconstruction: usefulness in high resolution chest CT

    International Nuclear Information System (INIS)

    Jeong, Sun Young; Chung, Myung Jin; Chong, Se Min; Sung, Yon Mi; Lee, Kyung Soo

    2006-01-01

    We tried to evaluate whether high resolution chest CT with a 1,024 matrix has a significant advantage in image quality compared to a 512 matrix. Each set of 512 and 1024 matrix high resolution chest CT scans with both 0.625 mm and 1.25 mm slice thickness were obtained from 26 patients. Seventy locations that contained twenty-four low density lesions without sharp boundary such as emphysema, and forty-six sharp linear densities such as linear fibrosis were selected; these were randomly displayed on a five mega pixel LCD monitor. All the images were masked for information concerning the matrix size and slice thickness. Two chest radiologists scored the image quality of each ar rowed lesion as follows: (1) undistinguishable, (2) poorly distinguishable, (3) fairly distinguishable, (4) well visible and (5) excellently visible. The scores were compared from the aspects of matrix size, slice thickness and the different observers by using ANOVA tests. The average and standard deviation of image quality were 3.09 (± .92) for the 0.625 mm x 512 matrix, 3.16 (± .84) for the 0.625 mm x 1024 matrix, 2.49 (± 1.02) for the 1.25 mm x 512 matrix, and 2.35 (± 1.02) for the 1.25 mm x 1024 matrix, respectively. The image quality on both matrices of the high resolution chest CT scans with a 0.625 mm slice thickness was significantly better than that on the 1.25 mm slice thickness (ρ < 0.001). However, the image quality on the 1024 matrix high resolution chest CT scans was not significantly different from that on the 512 matrix high resolution chest CT scans (ρ = 0.678). The interobserver variation between the two observers was not significant (ρ = 0.691). We think that 1024 matrix image reconstruction for high resolution chest CT may not be clinical useful

  4. Early clinical phase of patient's management after polytrauma using 1- and 4-slice helical CT; Fruehes klinisches Management nach Polytrauma mit 1- und 4-Schicht-Spiral-CT

    Energy Technology Data Exchange (ETDEWEB)

    Kloeppel, R.; Kahn, T. [Klinik und Poliklinik fuer Diagnostische Radiologie, Universitaetsklinikum Leipzig (Germany); Schreiter, D. [Chirurgische Intensivtherapieabteilung, Zentrum fuer Chirurgie, Universitaetsklinikum Leipzig (Germany); Dietrich, J. [Abt. Neuroradiologie der Klinik und Poliklinik fuer Diagnostische Radiologie, Universitaetsklinikum Leipzig (Germany); Josten, C. [Klinik und Poliklinik fuer Unfall- und Wiederherstellungschirurgie, Zentrum fuer Chirurgie, Universitaetsklinikum Leipzig (Germany)

    2002-07-01

    In the early clinical phase the comprehensive imaging of patients with multiple trauma using helical CT is already established. Aim of this study was to assess whether MSCT may improve the patient management and the diagnostic results.The procedure is designed as follows: after life-thretening treatment x-ray of chest and ultrasound are carried out in the emergency room. Then the patient is moved to CT. From 1998 to december 2000 241 patients were examined using a single slice helical CT (Somatom plus 4), in 2001 79 patients using a 4-slice helical CT (Somatom VZ, Siemens Med.Sol.). After CT selected radiograms of the extremities were taken.359 of 360 procedures were carried out successfully. Excluding 1 case (death during 1-sl. h CT) all relevant lesions of head, neck, and body were diagnosed. Although the patients had an injury severity score of {approx}30. The change from 1slice-helical CT to 4 slice-helical CT allowed us to reduce the stay in the CT room from 28 to 16 min. The total lethality decreased by {approx}4%.Advantages for the patient arose from the standardized examination protocol using multislice CT. If integrated in an interdisciplinary management concept, it is a good compromise between examination time, comprehensive diagnostic imaging, life-saving therapeutic procedures, and therapy planning. (orig.) [German] Die klinische Erstversorgung Polytraumatisierter schliesst inzwischen in vielen Unfallkliniken den fruehzeitigen Einsatz der Spiral-CT ein. Kann die neuerlich eingefuehrte Mehrschicht-Spiral-CT Ergebnisse und Patientenmanagement weiter verbessern?Nach lebensrettenden Sofortmassnahmen, Thoraxroentgen und Notsonographie im Schockraum erfolgte die CT: Von 1998-2000 wurden 241 Patienten mit einem 1-Schicht-Spiral-CT (Somatom plus 4) und in 2001 79 Patienten mit einem 4-Schicht-Spiral-CT (Somatom VZ, beide Siemens Med. Sol.) untersucht. Klinisch ausgewaehlte Extremitaetenaufnahmen wurden ergaenzt.359 von 360 Untersuchungen verliefen erfolgreich

  5. CT image reconstruction system based on hardware implementation

    International Nuclear Information System (INIS)

    Silva, Hamilton P. da; Evseev, Ivan; Schelin, Hugo R.; Paschuk, Sergei A.; Milhoretto, Edney; Setti, Joao A.P.; Zibetti, Marcelo; Hormaza, Joel M.; Lopes, Ricardo T.

    2009-01-01

    Full text: The timing factor is very important for medical imaging systems, which can nowadays be synchronized by vital human signals, like heartbeats or breath. The use of hardware implemented devices in such a system has advantages considering the high speed of information treatment combined with arbitrary low cost on the market. This article refers to a hardware system which is based on electronic programmable logic called FPGA, model Cyclone II from ALTERA Corporation. The hardware was implemented on the UP3 ALTERA Kit. A partially connected neural network with unitary weights was programmed. The system was tested with 60 topographic projections, 100 points in each, of the Shepp and Logan phantom created by MATLAB. The main restriction was found to be the memory size available on the device: the dynamic range of reconstructed image was limited to 0 65535. Also, the normalization factor must be observed in order to do not saturate the image during the reconstruction and filtering process. The test shows a principal possibility to build CT image reconstruction systems for any reasonable amount of input data by arranging the parallel work of the hardware units like we have tested. However, further studies are necessary for better understanding of the error propagation from topographic projections to reconstructed image within the implemented method. (author)

  6. Measuring of the airway dimensions with spiral CT images: an experimental study in Japanese white big-ear rabbits

    International Nuclear Information System (INIS)

    Han Xinwei; Lu Huibin; Ma Ji; Wu Gang; Wang Nan; Si Jiangtao

    2009-01-01

    Objective: To measure the length, angle and their correlation of the main anatomical dimensions of the trachea and bronchus in experimental Japanese white big-ear rabbits with the help of spiral CT 3D images, in order to lay the foundation of treating the airway disorders with stenting in animal experiment. Methods: Multi-slice CT scanning of cervico-thoracic region was performed in 30 healthy adult Japanese white big-ear rabbits, the longitudinal, transversal dimensions of the trachea, the glottis-carina length, the inner diameter and length of bronchi, and the angle formed by bronchial long axis and sagittal section were measured. Results: No significant difference was found in the inner diameters of various parts of the trachea and upper apical bronchi. The angle formed by bronchial long axis and sagittal section were smaller than that of the left ones. And the inner diameters of the right main bronchus was bigger than the left ones. Conclusion: The complex branching structure of the rabbit airway tree can be well displayed on spiral CT 3D images. Through measuring and statistical analysis of the results the authors have got a regressive equation for estimating the value of the inner diameter, length, angle, etc. concerning the airway tree, which is very helpful for providing the useful anatomical parameters in rabbit experiment. (authors)

  7. Diagnosis of bronchiectasis with multislice spiral CT: accuracy of 3-mm-thick structured sections

    Energy Technology Data Exchange (ETDEWEB)

    Remy-Jardin, Martine; Amara, Assia; Campistron, Philippe; Mastora, Ioana; Remy, Jacques [Department of Radiology, Hospital Calmette, University Center of Lille, Boulevard Jules Leclerc, 59037, Lille Cedex (France); Delannoy, Valerie; Duhamel, Alain [Department of Medical Statistics, University of Lille, Place de Verdun, 59037, Lille Cedex (France)

    2003-05-01

    The aim of this study was to evaluate the accuracy of 3-mm-thick reconstructed sections in the diagnosis of bronchiectasis with multislice CT (MSCT). Forty consecutive patients suspected of bronchiectasis (23 females, 17 males; mean age 51 years) underwent MSCT of the entire thorax with a 4 x 1-mm collimation (120 kV, 0.5 s/rotation, 80 mAs/slice) and a pitch of 1.75. From each data set (mean z-axis coverage: 257 mm; mean duration: 21 s), two series of images were systematically generated: 1-mm (group 1) and 3-mm (group 2)-thick reconstructed scans. Both series of images were obtained at 10-mm intervals and reconstructed with a high-spatial-frequency algorithm. Two observers independently analyzed the presence of bronchiectasis and associated abnormalities in group-1 and group-2 lung images. No significant difference between group 1 and group 2 was found in: (a) the detection of bronchiectasis, identified in 24 patients (60%) in group 1 and in 23 patients (57.5%) in group 2 (p=0.08); (b) the evaluation of the extent of bronchiectasis, identifying focal bronchiectasis in 10 patients (25%) in group 1 and 7 patients (17.5%) in group 2 (p=0.39) and multifocal bronchiectasis in 16 patients (40%) in both groups; (c) the characterisation of bronchiectasis (cylindral bronchiectasis: group 1, n=24, 60%; group 2, n=21, 53%, p=0.08); varicose bronchiectasis: group 1, n=5, 12.5%; group 2, n=6, 15%, p=0.56; and cystic bronchiectasis: group 1, n=2, 5%; group 2, n=2, 5%. Apart from the identification of abnormal bronchial wall thickening (group 2, n=35, 87.5%, vs group 1, n=31, 77.5%, p<0.05), recognition of associated bronchopulmonary anomalies did not differ between the two groups. This study demonstrates a comparable accuracy of the 3- and 1-mm-thick reconstructed scans in the detection and characterization of bronchiectasis. These results suggest the potential usefulness of 3-mm-thick scans generated from 4 x 2.5-mm acquisitions in the screening of bronchiectasis, which would

  8. Multi-slice spiral CT of the coronary arteries: improved vessel presentation by means of a standard software

    International Nuclear Information System (INIS)

    Schmitt, R.; Froehner, S.; Coblenz, G.; Christopoulos, G.; Brunn, J.; Mueller, M.; Kerber, S.; Fellner, F.

    2001-01-01

    Material and methods: Image data of 151 patients suffering from coronary artery disease were calculated by means of retrospective triggering at four different diastolic delay times in contrast-enhanced CT. The large coronary segments were subsequently reconstructed in two planes with multiplanar volume reconstruction (MPVR). Results: On the pre-condition that data sets were acquired at sinus rhythm and at a heart beat rate lower than 65/min coronary arteries could be depicted over a long distance in single or double angulated reconstruction planes with the help of MPVR. Time consumption for image reconstruction was reasonable. Additionally to the anatomy of the coronary arteries in two different planes, typical CT findings in occluding coronary artery disease are presented. (orig.) [de

  9. Value of multi-slice spiral CT in diagnosis the detection of fish bone impaction in the esophagus

    International Nuclear Information System (INIS)

    Luo Min; Hu Daoyu; Wang Qiuxia; Pei Yigang

    2009-01-01

    Objective: To investigate the detection rate and diagnostic value of multi-slice spiral CT scan in detecting fish bone impaction in the esophagus. Methods: Experimental group: 30 fresh water fish bones from three variety classes were divided into three groups with length of (23.36±0.15), (28.51± 0.07) and (30.89±0.10) mm, and diameter of (4.49±0.31), (1.78±0.09) and (0.49±0.07) mm. The fish bones were put into esophagus models in three different types including parallel, perpendicular and oblique. MSCT with axial scan combined with three dimensional reconstruction technique and plain X-ray film ( CR and DR) were used to examine the model. The relations of the number and rate of fish bones were compared between MSCT and X-ray film. Clinical group: MSCT imaging were performed in 20 cases proved by esophageal endoscope or clinical operation, among which 11 cases received plain X-ray film (CR and DR), 15 cases received Barium-soaked cotton and 17 cases received endoscope. Paired Chi-square test was used to compare the differences of detection of fishbone by the different ways. Results: In experimental group: All the 90 cases (100%) fish bones of three different species were clearly revealed on MSCT image; only 60 cases (66.7%) fish bones were revealed by plain X-ray film (CR and DR). The number and rate of fish bones detected by MSCT was higher than that of plain X-ray film (CR and DR) (χ 2 =28.03, P 2 =7.11, P 2 =4.17, P<0.05). Conclusions: The sensitivity and detection rate of fish bone with MSCT was high and could evaluate the surrounding and complications of the esophagus. MSCT could be used as the first examination of impacted fish bones in the esophagus. (authors)

  10. CT reconstruction techniques for improved accuracy of lung CT airway measurement

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, A. [Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705 (United States); Ranallo, F. N. [Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705 and Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792 (United States); Judy, P. F. [Brigham and Women’s Hospital, Boston, Massachusetts 02115 (United States); Gierada, D. S. [Department of Radiology, Washington University, St. Louis, Missouri 63110 (United States); Fain, S. B., E-mail: sfain@wisc.edu [Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705 (United States); Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792 (United States); Department of Biomedical Engineering,University of Wisconsin School of Engineering, Madison, Wisconsin 53706 (United States)

    2014-11-01

    Purpose: To determine the impact of constrained reconstruction techniques on quantitative CT (qCT) of the lung parenchyma and airways for low x-ray radiation dose. Methods: Measurement of small airways with qCT remains a challenge, especially for low x-ray dose protocols. Images of the COPDGene quality assurance phantom (CTP698, The Phantom Laboratory, Salem, NY) were obtained using a GE discovery CT750 HD scanner for helical scans at x-ray radiation dose-equivalents ranging from 1 to 4.12 mSv (12–100 mA s current–time product). Other parameters were 40 mm collimation, 0.984 pitch, 0.5 s rotation, and 0.625 mm thickness. The phantom was sandwiched between 7.5 cm thick water attenuating phantoms for a total length of 20 cm to better simulate the scatter conditions of patient scans. Image data sets were reconstructed using STANDARD (STD), DETAIL, BONE, and EDGE algorithms for filtered back projection (FBP), 100% adaptive statistical iterative reconstruction (ASIR), and Veo reconstructions. Reduced (half) display field of view (DFOV) was used to increase sampling across airway phantom structures. Inner diameter (ID), wall area percent (WA%), and wall thickness (WT) measurements of eight airway mimicking tubes in the phantom, including a 2.5 mm ID (42.6 WA%, 0.4 mm WT), 3 mm ID (49.0 WA%, 0.6 mm WT), and 6 mm ID (49.0 WA%, 1.2 mm WT) were performed with Airway Inspector (Surgical Planning Laboratory, Brigham and Women’s Hospital, Boston, MA) using the phase congruency edge detection method. The average of individual measures at five central slices of the phantom was taken to reduce measurement error. Results: WA% measures were greatly overestimated while IDs were underestimated for the smaller airways, especially for reconstructions at full DFOV (36 cm) using the STD kernel, due to poor sampling and spatial resolution (0.7 mm pixel size). Despite low radiation dose, the ID of the 6 mm ID airway was consistently measured accurately for all methods other than STD

  11. CT reconstruction techniques for improved accuracy of lung CT airway measurement

    International Nuclear Information System (INIS)

    Rodriguez, A.; Ranallo, F. N.; Judy, P. F.; Gierada, D. S.; Fain, S. B.

    2014-01-01

    Purpose: To determine the impact of constrained reconstruction techniques on quantitative CT (qCT) of the lung parenchyma and airways for low x-ray radiation dose. Methods: Measurement of small airways with qCT remains a challenge, especially for low x-ray dose protocols. Images of the COPDGene quality assurance phantom (CTP698, The Phantom Laboratory, Salem, NY) were obtained using a GE discovery CT750 HD scanner for helical scans at x-ray radiation dose-equivalents ranging from 1 to 4.12 mSv (12–100 mA s current–time product). Other parameters were 40 mm collimation, 0.984 pitch, 0.5 s rotation, and 0.625 mm thickness. The phantom was sandwiched between 7.5 cm thick water attenuating phantoms for a total length of 20 cm to better simulate the scatter conditions of patient scans. Image data sets were reconstructed using STANDARD (STD), DETAIL, BONE, and EDGE algorithms for filtered back projection (FBP), 100% adaptive statistical iterative reconstruction (ASIR), and Veo reconstructions. Reduced (half) display field of view (DFOV) was used to increase sampling across airway phantom structures. Inner diameter (ID), wall area percent (WA%), and wall thickness (WT) measurements of eight airway mimicking tubes in the phantom, including a 2.5 mm ID (42.6 WA%, 0.4 mm WT), 3 mm ID (49.0 WA%, 0.6 mm WT), and 6 mm ID (49.0 WA%, 1.2 mm WT) were performed with Airway Inspector (Surgical Planning Laboratory, Brigham and Women’s Hospital, Boston, MA) using the phase congruency edge detection method. The average of individual measures at five central slices of the phantom was taken to reduce measurement error. Results: WA% measures were greatly overestimated while IDs were underestimated for the smaller airways, especially for reconstructions at full DFOV (36 cm) using the STD kernel, due to poor sampling and spatial resolution (0.7 mm pixel size). Despite low radiation dose, the ID of the 6 mm ID airway was consistently measured accurately for all methods other than STD

  12. New reconstruction algorithm in helical-volume CT

    International Nuclear Information System (INIS)

    Toki, Y.; Rifu, T.; Aradate, H.; Hirao, Y.; Ohyama, N.

    1990-01-01

    This paper reports on helical scanning that is an application of continuous scanning CT to acquire volume data in a short time for three-dimensional study. In a helical scan, the patient couch sustains movement during continuous-rotation scanning and then the acquired data is processed to synthesize a projection data set of vertical section by interpolation. But the synthesized section is not thin enough; also, the image may have artifacts caused by couch movement. A new reconstruction algorithm that helps resolve such problems has been developed and compared with the ordinary algorithm. The authors constructed a helical scan system based on TCT-900S, which can perform 1-second rotation continuously for 30 seconds. The authors measured section thickness using both algorithms on an AAPM phantom, and we also compared degree of artifacts on clinical data

  13. Iterative Reconstruction Techniques in Abdominopelvic CT: Technical Concepts and Clinical Implementation.

    Science.gov (United States)

    Patino, Manuel; Fuentes, Jorge M; Singh, Sarabjeet; Hahn, Peter F; Sahani, Dushyant V

    2015-07-01

    This article discusses the clinical challenge of low-radiation-dose examinations, the commonly used approaches for dose optimization, and their effect on image quality. We emphasize practical aspects of the different iterative reconstruction techniques, along with their benefits, pitfalls, and clinical implementation. The widespread use of CT has raised concerns about potential radiation risks, motivating diverse strategies to reduce the radiation dose associated with CT. CT manufacturers have developed alternative reconstruction algorithms intended to improve image quality on dose-optimized CT studies, mainly through noise and artifact reduction. Iterative reconstruction techniques take unique approaches to noise reduction and provide distinct strength levels or settings.

  14. Model-based iterative reconstruction for reduction of radiation dose in abdominopelvic CT: comparison to adaptive statistical iterative reconstruction.

    Science.gov (United States)

    Yasaka, Koichiro; Katsura, Masaki; Akahane, Masaaki; Sato, Jiro; Matsuda, Izuru; Ohtomo, Kuni

    2013-12-01

    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). 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). Image noise was measured in the abdominal aorta and iliopsoas muscle. Subjective image analyses and a lesion detection study (adrenal nodules) were conducted by two blinded radiologists. A reference standard was established by a consensus panel of two different radiologists using referential-dose CT reconstructed with filtered back projection. Compared to low-dose CT, there was a 63% decrease in dose-length product with ultralow-dose CT. UL-MBIR had significantly lower image noise than L-ASIR and UL-ASIR (all pASIR and UL-ASIR (all pASIR in diagnostic acceptability (p>0.65), or diagnostic performance for adrenal nodules (p>0.87). MBIR significantly improves image noise and streak artifacts compared to ASIR, and can achieve radiation dose reduction without severely compromising image quality.

  15. Task-based optimization of image reconstruction in breast CT

    Science.gov (United States)

    Sanchez, Adrian A.; Sidky, Emil Y.; Pan, Xiaochuan

    2014-03-01

    We demonstrate a task-based assessment of image quality in dedicated breast CT in order to optimize the number of projection views acquired. The methodology we employ is based on the Hotelling Observer (HO) and its associated metrics. We consider two tasks: the Rayleigh task of discerning between two resolvable objects and a single larger object, and the signal detection task of classifying an image as belonging to either a signalpresent or signal-absent hypothesis. HO SNR values are computed for 50, 100, 200, 500, and 1000 projection view images, with the total imaging radiation dose held constant. We use the conventional fan-beam FBP algorithm and investigate the effect of varying the width of a Hanning window used in the reconstruction, since this affects both the noise properties of the image and the under-sampling artifacts which can arise in the case of sparse-view acquisitions. Our results demonstrate that fewer projection views should be used in order to increase HO performance, which in this case constitutes an upper-bound on human observer performance. However, the impact on HO SNR of using fewer projection views, each with a higher dose, is not as significant as the impact of employing regularization in the FBP reconstruction through a Hanning filter.

  16. Novel ultrahigh resolution data acquisition and image reconstruction for multi-detector row CT

    International Nuclear Information System (INIS)

    Flohr, T. G.; Stierstorfer, K.; Suess, C.; Schmidt, B.; Primak, A. N.; McCollough, C. H.

    2007-01-01

    We present and evaluate a special ultrahigh resolution mode providing considerably enhanced spatial resolution both in the scan plane and in the z-axis direction for a routine medical multi-detector row computed tomography (CT) system. Data acquisition is performed by using a flying focal spot both in the scan plane and in the z-axis direction in combination with tantalum grids that are inserted in front of the multi-row detector to reduce the aperture of the detector elements both in-plane and in the z-axis direction. The dose utilization of the system for standard applications is not affected, since the grids are moved into place only when needed and are removed for standard scanning. By means of this technique, image slices with a nominal section width of 0.4 mm (measured full width at half maximum=0.45 mm) can be reconstructed in spiral mode on a CT system with a detector configuration of 32x0.6 mm. The measured 2% value of the in-plane modulation transfer function (MTF) is 20.4 lp/cm, the measured 2% value of the longitudinal (z axis) MTF is 21.5 lp/cm. In a resolution phantom with metal line pair test patterns, spatial resolution of 20 lp/cm can be demonstrated both in the scan plane and along the z axis. This corresponds to an object size of 0.25 mm that can be resolved. The new mode is intended for ultrahigh resolution bone imaging, in particular for wrists, joints, and inner ear studies, where a higher level of image noise due to the reduced aperture is an acceptable trade-off for the clinical benefit brought about by the improved spatial resolution

  17. Low-dose CT image reconstruction using gain intervention-based dictionary learning

    Science.gov (United States)

    Pathak, Yadunath; Arya, K. V.; Tiwari, Shailendra

    2018-05-01

    Computed tomography (CT) approach is extensively utilized in clinical diagnoses. However, X-ray residue in human body may introduce somatic damage such as cancer. Owing to radiation risk, research has focused on the radiation exposure distributed to patients through CT investigations. Therefore, low-dose CT has become a significant research area. Many researchers have proposed different low-dose CT reconstruction techniques. But, these techniques suffer from various issues such as over smoothing, artifacts, noise, etc. Therefore, in this paper, we have proposed a novel integrated low-dose CT reconstruction technique. The proposed technique utilizes global dictionary-based statistical iterative reconstruction (GDSIR) and adaptive dictionary-based statistical iterative reconstruction (ADSIR)-based reconstruction techniques. In case the dictionary (D) is predetermined, then GDSIR can be used and if D is adaptively defined then ADSIR is appropriate choice. The gain intervention-based filter is also used as a post-processing technique for removing the artifacts from low-dose CT reconstructed images. Experiments have been done by considering the proposed and other low-dose CT reconstruction techniques on well-known benchmark CT images. Extensive experiments have shown that the proposed technique outperforms the available approaches.

  18. Image quality of multiplanar reconstruction of pulmonary CT scans using adaptive statistical iterative reconstruction.

    Science.gov (United States)

    Honda, O; Yanagawa, M; Inoue, A; Kikuyama, A; Yoshida, S; Sumikawa, H; Tobino, K; Koyama, M; Tomiyama, N

    2011-04-01

    We investigated the image quality of multiplanar reconstruction (MPR) using adaptive statistical iterative reconstruction (ASIR). Inflated and fixed lungs were scanned with a garnet detector CT in high-resolution mode (HR mode) or non-high-resolution (HR) mode, and MPR images were then reconstructed. Observers compared 15 MPR images of ASIR (40%) and ASIR (80%) with those of ASIR (0%), and assessed image quality using a visual five-point scale (1, definitely inferior; 5, definitely superior), with particular emphasis on normal pulmonary structures, artefacts, noise and overall image quality. The mean overall image quality scores in HR mode were 3.67 with ASIR (40%) and 4.97 with ASIR (80%). Those in non-HR mode were 3.27 with ASIR (40%) and 3.90 with ASIR (80%). The mean artefact scores in HR mode were 3.13 with ASIR (40%) and 3.63 with ASIR (80%), but those in non-HR mode were 2.87 with ASIR (40%) and 2.53 with ASIR (80%). The mean scores of the other parameters were greater than 3, whereas those in HR mode were higher than those in non-HR mode. There were significant differences between ASIR (40%) and ASIR (80%) in overall image quality (pASIR did not suppress the severe artefacts of contrast medium. In general, MPR image quality with ASIR (80%) was superior to that with ASIR (40%). However, there was an increased incidence of artefacts by ASIR when CT images were obtained in non-HR mode.

  19. Characterization of liver lesions with mangafodipir trisodium-enhanced MR imaging: multicenter study comparing MR and dual-phase spiral CT

    NARCIS (Netherlands)

    M. Oudkerk (Matthijs); C.G. Torres; B. Song; M. Konig; J. Grimm; J. Fernandez-Cuadrado; B. op de Beeck; M. Marquardt; P. van Dijk (Pieter); J.C. de Groot (Jan Cees)

    2002-01-01

    textabstractPURPOSE: To evaluate whether mangafodipir trisodium (Mn-DPDP)-enhanced magnetic resonance (MR) imaging surpasses dual-phase spiral computed tomography (CT) in differentiating focal liver lesions. MATERIALS AND METHODS: One hundred forty-five patients who had or were

  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 standard-dose FBP CT (16.6 ± 2.3 HU, p 70%, MBIR can provide

  1. Optimization of SPECT-CT Hybrid Imaging Using Iterative Image Reconstruction for Low-Dose CT: A Phantom Study.

    Directory of Open Access Journals (Sweden)

    Oliver S Grosser

    Full Text Available Hybrid imaging combines nuclear medicine imaging such as single photon emission computed tomography (SPECT or positron emission tomography (PET with computed tomography (CT. Through this hybrid design, scanned patients accumulate radiation exposure from both applications. Imaging modalities have been the subject of long-term optimization efforts, focusing on diagnostic applications. It was the aim of this study to investigate the influence of an iterative CT image reconstruction algorithm (ASIR on the image quality of the low-dose CT images.Examinations were performed with a SPECT-CT scanner with standardized CT and SPECT-phantom geometries and CT protocols with systematically reduced X-ray tube currents. Analyses included image quality with respect to photon flux. Results were compared to the standard FBP reconstructed images. The general impact of the CT-based attenuation maps used during SPECT reconstruction was examined for two SPECT phantoms. Using ASIR for image reconstructions, image noise was reduced compared to FBP reconstructions for the same X-ray tube current. The Hounsfield unit (HU values reconstructed by ASIR were correlated to the FBP HU values(R2 ≥ 0.88 and the contrast-to-noise ratio (CNR was improved by ASIR. However, for a phantom with increased attenuation, the HU values shifted for low X-ray tube currents I ≤ 60 mA (p ≤ 0.04. In addition, the shift of the HU values was observed within the attenuation corrected SPECT images for very low X-ray tube currents (I ≤ 20 mA, p ≤ 0.001.In general, the decrease in X-ray tube current up to 30 mA in combination with ASIR led to a reduction of CT-related radiation exposure without a significant decrease in image quality.

  2. Radiation exposure in multi-slice versus single-slice spiral CT: results of a nationwide survey

    International Nuclear Information System (INIS)

    Brix, G.; Nagel, H.D.; Stamm, G.; Veit, R.; Lechel, U.; Griebel, J.; Galanski, M.

    2003-01-01

    Multi-slice (MS) technology increases the efficacy of CT procedures and offers new promising applications. The expanding use of MSCT, however, may result in an increase in both frequency of procedures and levels of patient exposure. It was, therefore, the aim of this study to gain an overview of MSCT examinations conducted in Germany in 2001. All MSCT facilities were requested to provide information about 14 standard examinations with respect to scan parameters and frequency. Based on this data, dosimetric quantities were estimated using an experimentally validated formalism. Results are compared with those of a previous survey for single-slice (SS) spiral CT scanners. According to the data provided for 39 dual- and 73 quad-slice systems, the average annual number of patients examined at MSCT is markedly higher than that examined at SSCT scanners (5500 vs 3500). The average effective dose to patients was changed from 7.4 mSv at single-slice to 5.5 mSv and 8.1 mSv at dual- and quad-slice scanners, respectively. There is a considerable potential for dose reduction at quad-slice systems by an optimisation of scan protocols and better education of the personnel. To avoid an increase in the collective effective dose from CT procedures, a clear medical justification is required in each case. (orig.)

  3. Virtual reality publication of spiral ct-derived three-dimensional models: or, creation of spiral, CT-derived, three-dimensional VRML objects.

    Science.gov (United States)

    Tyszka, J M

    1997-01-01

    Three-dimensional models can be generated from slice images, such as those obtained from computed tomography (CT) and magnetic resonance imaging (MRI) using a variety of techniques. A popular method for rendering 3D anatomical models is the creation of polygonal mesh surfaces representing the boundary between tissues. Mesh surfaces can be rendered extremely quickly using conventional personal computers, without recourse to more expensive graphic workstations. The dissemination of three-dimensional (3D) models across the Internet has been made significantly easier by the definition of the Virtual Reality Markup Language (VRML) format. The VRML definition allows the parameters and relationships of 3D objects to be described in a text format. The text file can be transfered from a host computer to a remote client computer through the World Wide Web and viewed using readily available software (See Appendix). VRML is based on the definition of primitive 3D objects such as polygons and spheres. Consequently, the transition from a mesh surface derived from a clinical image data set to a VRML object is relatively simple, allowing for convenient and cost-effective dissemination of 3D clinical models across the internet.

  4. Color-coded volume rendering for three-dimensional reconstructions of CT data

    International Nuclear Information System (INIS)

    Rieker, O.; Mildenberger, P.; Thelen, M.

    1999-01-01

    Purpose: To evaluate a technique of colored three-dimensional reconstructions without segmentation. Material and methods: Color-coded volume rendered images were reconstructed from the volume data of 25 thoracic, abdominal, musculoskeletal, and vascular helical CT scans using commercial software. The CT volume rendered voxels were encoded with color in the following manner. Opacity, hue, lightness, and chroma were assigned to each of four classes defined by CT number. Color-coded reconstructions were compared to the corresponding grey-scale coded reconstructions. Results: Color-coded volume rendering enabled realistic visualization of pathologic findings when there was sufficient difference in CT density. Segmentation was necessary in some cases to demonstrate small details in a complex volume. Conclusion: Color-coded volume rendering allowed lifelike visualisation of CT volumes without the need of segmentation in most cases. (orig.) [de

  5. SU-E-I-73: Clinical Evaluation of CT Image Reconstructed Using Interior Tomography

    International Nuclear Information System (INIS)

    Zhang, J; Ge, G; Winkler, M; Cong, W; Wang, G

    2014-01-01

    Purpose: Radiation dose reduction has been a long standing challenge in CT imaging of obese patients. Recent advances in interior tomography (reconstruction of an interior region of interest (ROI) from line integrals associated with only paths through the ROI) promise to achieve significant radiation dose reduction without compromising image quality. This study is to investigate the application of this technique in CT imaging through evaluating imaging quality reconstructed from patient data. Methods: Projection data were directly obtained from patients who had CT examinations in a Dual Source CT scanner (DSCT). Two detectors in a DSCT acquired projection data simultaneously. One detector provided projection data for full field of view (FOV, 50 cm) while another detectors provided truncated projection data for a FOV of 26 cm. Full FOV CT images were reconstructed using both filtered back projection and iterative algorithm; while interior tomography algorithm was implemented to reconstruct ROI images. For comparison reason, FBP was also used to reconstruct ROI images. Reconstructed CT images were evaluated by radiologists and compared with images from CT scanner. Results: The results show that the reconstructed ROI image was in excellent agreement with the truth inside the ROI, obtained from images from CT scanner, and the detailed features in the ROI were quantitatively accurate. Radiologists evaluation shows that CT images reconstructed with interior tomography met diagnosis requirements. Radiation dose may be reduced up to 50% using interior tomography, depending on patient size. Conclusion: This study shows that interior tomography can be readily employed in CT imaging for radiation dose reduction. It may be especially useful in imaging obese patients, whose subcutaneous tissue is less clinically relevant but may significantly increase radiation dose

  6. 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

  7. Multiphasic helical CT of hepatocellular carcinoma. Evaluation after chemoembolization; Tomografia Computerizzata spirale multifasica dell'epatocarcinoma. Valutazione dopo chemioembolizzazione

    Energy Technology Data Exchange (ETDEWEB)

    Catalano, O.; Esposito, M.; Sandomenico, F.; Siani, A. [Ospedale S. Maria delle Grazie, Pozzuoli, NA (Italy). Servizio di Radiologia; Nunziata, A. [Ospedale S. Maria delle Grazie, Naples (Italy). Area di Diagnostica per Immagini

    2000-06-01

    The main purpose of this work is to report the personal experience with addition of contrast-enhanced multiphase helical CT to unenhanced CT (Lipiodol CT) in the evaluation of patients with hepatocellular carcinoma treated with chemoembolization and to analyze the present role of oily agent CT. It has been retrospectively reviewed the examinations of 42 consecutive patients submitted to global chemoembolization over a 2-year period. CT was performed 18-30 days after the treatment. The Lipiodol CT study was carried out with volume acquisitions. It has been considered as nodules all well-defined areas with dense oily agent uptake; uptake itself was classified as: 0=absent, I=lower than 10% of the tumor volume; II=lower than 50%, III=50%, IV=homogeneous. Contrast-enhanced helical CT was performed with the 2-phase technique in 28 patients and with the 3-phase technique in 14; it has been considered as nodules all well-defined and relatively homogeneous areas with hyper attenuation in the arterial phase and hypo-iso attenuation in the portal and/or delayed phase, or with hypo-iso attenuation in the arterial phase and in the portal and/or delayed phase. Lipiodol CT permitted to recognize 65 nodules (1-5/patient, mean 1.5), namely 15 grade I, 21 grade II, 20 grade III and 9 grade IV. Multiphase CT identified 6 additional nodules in 5 patients, 5 hyper vascular and 1 hypo vascular, and better assessed the correct morphology and volume of grade I nodules. Only 4 of 6 nodules missed on Lipiodol CT showed oily agent uptake after a new chemo embolization session. Moreover after retreatment, carried out in 6 of 9 patients with grade I uptake (11 nodules in all), it has been found persistence of the grade I pattern in 5 nodules, grade II in 5, and grade III in 1. Lipiodol CT may miss liver nodules and underestimate the volume of nodules with poor uptake. Though Lipiodol CT should still be considered slightly more sensitive than multiphase CT, in the general opinion this

  8. Dose reduction with adaptive statistical iterative reconstruction for paediatric CT: phantom study and clinical experience on chest and abdomen CT.

    Science.gov (United States)

    Gay, F; Pavia, Y; Pierrat, N; Lasalle, S; Neuenschwander, S; Brisse, H J

    2014-01-01

    To assess the benefit and limits of iterative reconstruction of paediatric chest and abdominal computed tomography (CT). The study compared adaptive statistical iterative reconstruction (ASIR) with filtered back projection (FBP) on 64-channel MDCT. A phantom study was first performed using variable tube potential, tube current and ASIR settings. The assessed image quality indices were the signal-to-noise ratio (SNR), the noise power spectrum, low contrast detectability (LCD) and spatial resolution. A clinical retrospective study of 26 children (M:F = 14/12, mean age: 4 years, range: 1-9 years) was secondarily performed allowing comparison of 18 chest and 14 abdominal CT pairs, one with a routine CT dose and FBP reconstruction, and the other with 30 % lower dose and 40 % ASIR reconstruction. Two radiologists independently compared the images for overall image quality, noise, sharpness and artefacts, and measured image noise. The phantom study demonstrated a significant increase in SNR without impairment of the LCD or spatial resolution, except for tube current values below 30-50 mA. On clinical images, no significant difference was observed between FBP and reduced dose ASIR images. Iterative reconstruction allows at least 30 % dose reduction in paediatric chest and abdominal CT, without impairment of image quality. • Iterative reconstruction helps lower radiation exposure levels in children undergoing CT. • Adaptive statistical iterative reconstruction (ASIR) significantly increases SNR without impairing spatial resolution. • For abdomen and chest CT, ASIR allows at least a 30 % dose reduction.

  9. Enhanced temporal resolution at cardiac CT with a novel CT image reconstruction algorithm: Initial patient experience

    Energy Technology Data Exchange (ETDEWEB)

    Apfaltrer, Paul, E-mail: paul.apfaltrer@medma.uni-heidelberg.de [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, PO Box 250322, 169 Ashley Avenue, Charleston, SC 29425 (United States); Institute of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim (Germany); Schoendube, Harald, E-mail: harald.schoendube@siemens.com [Siemens Healthcare, CT Division, Forchheim Siemens, Siemensstr. 1, 91301 Forchheim (Germany); Schoepf, U. Joseph, E-mail: schoepf@musc.edu [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, PO Box 250322, 169 Ashley Avenue, Charleston, SC 29425 (United States); Allmendinger, Thomas, E-mail: thomas.allmendinger@siemens.com [Siemens Healthcare, CT Division, Forchheim Siemens, Siemensstr. 1, 91301 Forchheim (Germany); Tricarico, Francesco, E-mail: francescotricarico82@gmail.com [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, PO Box 250322, 169 Ashley Avenue, Charleston, SC 29425 (United States); Department of Bioimaging and Radiological Sciences, Catholic University of the Sacred Heart, “A. Gemelli” Hospital, Largo A. Gemelli 8, Rome (Italy); Schindler, Andreas, E-mail: andreas.schindler@campus.lmu.de [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, PO Box 250322, 169 Ashley Avenue, Charleston, SC 29425 (United States); Vogt, Sebastian, E-mail: sebastian.vogt@siemens.com [Siemens Healthcare, CT Division, Forchheim Siemens, Siemensstr. 1, 91301 Forchheim (Germany); Sunnegårdh, Johan, E-mail: johan.sunnegardh@siemens.com [Siemens Healthcare, CT Division, Forchheim Siemens, Siemensstr. 1, 91301 Forchheim (Germany); and others

    2013-02-15

    Objective: To evaluate the effect of a temporal resolution improvement method (TRIM) for cardiac CT on diagnostic image quality for coronary artery assessment. Materials and methods: The TRIM-algorithm employs an iterative approach to reconstruct images from less than 180° of projections and uses a histogram constraint to prevent the occurrence of limited-angle artifacts. This algorithm was applied in 11 obese patients (7 men, 67.2 ± 9.8 years) who had undergone second generation dual-source cardiac CT with 120 kV, 175–426 mAs, and 500 ms gantry rotation. All data were reconstructed with a temporal resolution of 250 ms using traditional filtered-back projection (FBP) and of 200 ms using the TRIM-algorithm. Contrast attenuation and contrast-to-noise-ratio (CNR) were measured in the ascending aorta. The presence and severity of coronary motion artifacts was rated on a 4-point Likert scale. Results: All scans were considered of diagnostic quality. Mean BMI was 36 ± 3.6 kg/m{sup 2}. Average heart rate was 60 ± 9 bpm. Mean effective dose was 13.5 ± 4.6 mSv. When comparing FBP- and TRIM reconstructed series, the attenuation within the ascending aorta (392 ± 70.7 vs. 396.8 ± 70.1 HU, p > 0.05) and CNR (13.2 ± 3.2 vs. 11.7 ± 3.1, p > 0.05) were not significantly different. A total of 110 coronary segments were evaluated. All studies were deemed diagnostic; however, there was a significant (p < 0.05) difference in the severity score distribution of coronary motion artifacts between FBP (median = 2.5) and TRIM (median = 2.0) reconstructions. Conclusion: The algorithm evaluated here delivers diagnostic imaging quality of the coronary arteries despite 500 ms gantry rotation. Possible applications include improvement of cardiac imaging on slower gantry rotation systems or mitigation of the trade-off between temporal resolution and CNR in obese patients.

  10. Evaluation of image quality and dose in thoracic spiral CT examination in patients with pulmonary carcinoma. Preliminary results

    International Nuclear Information System (INIS)

    Moran-Blanco, L. M.; Rodriguez-Gonzalez, R.; Calzado-Cantera, A.; Arenas de Pablo, A.; Baeza-Trujillo, M.; Cuevas-Ibanez, A.; Garcia-Castano, B.; Gomez-Leon, N.; Turrero-Nogues, A.; Moran-Penco, P.

    2002-01-01

    We have applied criteria for CT quality defined in the European Guidelines to a samples of thoracic CT examinations for the indication of pulmonary carcinoma of 5 institutions of the Community of Madrid that have spiral CT equipment. The selected examinations have been evaluated independently by five radiologists to determine the degree of adherence to the quality criteria for image defined in the Guidelines s for examinations of general thorax. Dosimetric measurements carried out in parallel have served to estimate the values of CT (CTDI w ) dose indices, dose-length product (DLP) and effective dose for every patient. The result show a high global adherence to the quality criteria (96%), with averages per institution being between 94% (in two institutions) and 98% (in three institutions). There are 10 of 16 criteria that are adhered to in all examinations of the sample: those which are not adhered to systematically are: two of visualization (1.1 and 1.4), with 92-96% fulfillment, and four of critical reproduction (2.6; 2.8; 2.9 and 2.10), with percentages of adherence between 91% and 96%. The average CTDI w values per institution are in the interval 12.9-19.1 mGy; those of DLP between 263 and 577 mGy cm and those of effective dose between 4.2 and 9.2 mSv. The DLP-image quality correlation in institutions with the best image quality was null in two of them and direct and moderate in the third. In both institutions with the poorest image: (Author) 20 refs

  11. Postoperative evaluation after anterior cruciate ligament reconstruction: Measurements and abnormalities on radiographic and CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Cheol; Choi, Yun Sun; KIm, Hyoung Seop; Choi, Nam Hong [Nowon Eulji Medical Center, Eulji University, Seoul (Korea, Republic of)

    2016-11-15

    Reconstruction of a ruptured anterior cruciate ligament (ACL) is a well-established procedure for repair of ACL injury. Despite improvement of surgical and rehabilitation techniques over the past decades, up to 25% of patients still fail to regain satisfactory function after an ACL reconstruction. With development of CT imaging techniques for reducing metal artifacts, multi-planar reconstruction, and three-dimensional reconstruction, early post-operative imaging is increasingly being used to provide immediate feedback to surgeons regarding tunnel positioning, fixation, and device placement. Early post-operative radiography and CT imaging are easy to perform and serve as the baseline examinations for future reference.

  12. A comparison of linear interpolation models for iterative CT reconstruction.

    Science.gov (United States)

    Hahn, Katharina; Schöndube, Harald; Stierstorfer, Karl; Hornegger, Joachim; Noo, Frédéric

    2016-12-01

    Recent reports indicate that model-based iterative reconstruction methods may improve image quality in computed tomography (CT). One difficulty with these methods is the number of options available to implement them, including the selection of the forward projection model and the penalty term. Currently, the literature is fairly scarce in terms of guidance regarding this selection step, whereas these options impact image quality. Here, the authors investigate the merits of three forward projection models that rely on linear interpolation: the distance-driven method, Joseph's method, and the bilinear method. The authors' selection is motivated by three factors: (1) in CT, linear interpolation is often seen as a suitable trade-off between discretization errors and computational cost, (2) the first two methods are popular with manufacturers, and (3) the third method enables assessing the importance of a key assumption in the other methods. One approach to evaluate forward projection models is to inspect their effect on discretized images, as well as the effect of their transpose on data sets, but significance of such studies is unclear since the matrix and its transpose are always jointly used in iterative reconstruction. Another approach is to investigate the models in the context they are used, i.e., together with statistical weights and a penalty term. Unfortunately, this approach requires the selection of a preferred objective function and does not provide clear information on features that are intrinsic to the model. The authors adopted the following two-stage methodology. First, the authors analyze images that progressively include components of the singular value decomposition of the model in a reconstructed image without statistical weights and penalty term. Next, the authors examine the impact of weights and penalty on observed differences. Image quality metrics were investigated for 16 different fan-beam imaging scenarios that enabled probing various aspects

  13. Clinical investigation of flat panel CT following middle ear reconstruction: a study of 107 patients

    Energy Technology Data Exchange (ETDEWEB)

    Zaoui, K. [University Hospital Heidelberg, Ruprecht Karls University, Department of Otorhinolaryngology, Head and Neck Surgery, Heidelberg (Germany); Kromeier, J. [St. Josefs Hospital, RkK, Department of Radiology, Freiburg (Germany); Neudert, M.; Beleites, T.; Zahnert, T. [University Hospital Dresden, Technical University, Department of Otorhinolaryngology, Head and Neck Surgery, Dresden (Germany); Laszig, R.; Offergeld, C. [University Hospital Freiburg, Albert Ludwigs University, Department of Otorhinolaryngology, Head and Neck Surgery, Freiburg (Germany)

    2014-03-15

    After middle ear reconstruction using partial or total ossicular replacement prostheses (PORP/TORP), an air-bone gap (ABG) may persist because of prosthesis displacement or malposition. So far, CT of the temporal bone has played the main role in the diagnosis of reasons for postoperative insufficient ABG improvement. Recent experimental and clinical studies have evaluated flat panel CT (fpCT) as an alternative imaging technique that provides images with high isovolumetric resolution, fewer metal-induced artefacts and lower irradiation doses. One hundred and seven consecutive patients with chronic otitis media with or without cholesteatoma underwent reconstruction by PORP (n = 52) or TORP (n = 55). All subjects underwent preoperative and postoperative audiometric testing and postoperative fpCT. Statistical evaluation of all 107 patients as well as the sole sub-assembly groups (PORP or TORP) showed a highly significant correlation between hearing improvement and fpCT-determined prosthesis position. FpCT enables detailed postoperative information on patients with middle ear reconstruction. FpCT is a new imaging technique that provides immediate feedback on surgical results after reconstructive middle ear surgery. Specific parameters evaluated by fpCT may serve as a predictive tool for estimated postoperative hearing improvement. Therefore this imaging technique is suitable for postoperative quality control in reconstructive middle ear surgery. (orig.)

  14. Congenital intrahepatic arterioportal and portosystemic venous fistulae with jejunal arteriovenous malformation depicted on multislice spiral CT

    International Nuclear Information System (INIS)

    Chae, Eun Jin; Goo, Hyun Woo; Yoon, Chong Hyun; Kim, Seong-Chul

    2004-01-01

    We report a symptomatic infant with very rare congenital arterioportal and portosystemic venous fistulae in the liver. Multislice CT after partial transcatheter embolisation revealed not only the complicated vascular architecture of the lesion, but also an incidental jejunal arteriovenous malformation which explained the patient's melena. The patient underwent ligation of the hepatic artery and resection of the jejunal arteriovenous malformation. Postoperative multislice CT clearly demonstrated the success of the treatment. (orig.)

  15. Gastrointestinal stromal tumor: role of spiral CT in diagnosis and evaluation of treatment with STI571

    International Nuclear Information System (INIS)

    Hu Jiawang; Zhou Linjiang; Wei Jiangong

    2011-01-01

    Objective: To investigate the CT appearance of gastrointestinal stromal tumors (GISTs) after oral imatinib mesylate (STI571) treatment. Methods: CT scans of 58 cases of GISTs proven by histology and immunohistochemistry were retrospectively analyzed. Dynamic contrast-enhanced CT of 8 patients after STI571 treatment was also evaluated. Results: The tumors originated from the stomach (n=28), small intestine (n=12), duodenum (n=6), colon (n=5), rectum (n=4), mesentery (n=2), and esophagus (n=2). Small GISTs appeared as round or oval, endo- or exophytic masses with well-defined margins and homogeneous contrast enhancement. Large lesions were often irregular infiltrative exophytic masses with heterogeneous enhancement. Ulceration, fistulization and neovascularity can be seen within the larger tumors. CT scans of 5 patients with good treatment response showed rapid transition form a heterogeneously hyper-attenuating pattern to homogeneously hypo-attenuating pattern with resolution of the enhancing tumor nodules and decreased tumor neovascularity. In 3 poor responders, CT showed enlarging or new enhancing nodules within the treated hypo-attenuating tumor, new lesions or metastasis outside the primary tumor. Conclusion: CT can demonstrate changes resulting from treatment of GISTs. It is valuable for guiding and assessing treatment response to STI571. (authors)

  16. Ultralow dose computed tomography attenuation correction for pediatric PET CT using adaptive statistical iterative reconstruction

    International Nuclear Information System (INIS)

    Brady, Samuel L.; Shulkin, Barry L.

    2015-01-01

    Purpose: To develop ultralow dose computed tomography (CT) attenuation correction (CTAC) acquisition protocols for pediatric positron emission tomography CT (PET CT). Methods: A GE Discovery 690 PET CT hybrid scanner was used to investigate the change to quantitative PET and CT measurements when operated at ultralow doses (10–35 mA s). CT quantitation: noise, low-contrast resolution, and CT numbers for 11 tissue substitutes were analyzed in-phantom. CT quantitation was analyzed to a reduction of 90% volume computed tomography dose index (0.39/3.64; mGy) from baseline. To minimize noise infiltration, 100% adaptive statistical iterative reconstruction (ASiR) was used for CT reconstruction. PET images were reconstructed with the lower-dose CTAC iterations and analyzed for: maximum body weight standardized uptake value (SUV bw ) of various diameter targets (range 8–37 mm), background uniformity, and spatial resolution. Radiation dose and CTAC noise magnitude were compared for 140 patient examinations (76 post-ASiR implementation) to determine relative dose reduction and noise control. Results: CT numbers were constant to within 10% from the nondose reduced CTAC image for 90% dose reduction. No change in SUV bw , background percent uniformity, or spatial resolution for PET images reconstructed with CTAC protocols was found down to 90% dose reduction. Patient population effective dose analysis demonstrated relative CTAC dose reductions between 62% and 86% (3.2/8.3–0.9/6.2). Noise magnitude in dose-reduced patient images increased but was not statistically different from predose-reduced patient images. Conclusions: Using ASiR allowed for aggressive reduction in CT dose with no change in PET reconstructed images while maintaining sufficient image quality for colocalization of hybrid CT anatomy and PET radioisotope uptake

  17. Ultralow dose computed tomography attenuation correction for pediatric PET CT using adaptive statistical iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Samuel L., E-mail: samuel.brady@stjude.org [Division of Diagnostic Imaging, St. Jude Children’s Research Hospital, Memphis, Tennessee 38105 (United States); Shulkin, Barry L. [Nuclear Medicine and Department of Radiological Sciences, St. Jude Children’s Research Hospital, Memphis, Tennessee 38105 (United States)

    2015-02-15

    Purpose: To develop ultralow dose computed tomography (CT) attenuation correction (CTAC) acquisition protocols for pediatric positron emission tomography CT (PET CT). Methods: A GE Discovery 690 PET CT hybrid scanner was used to investigate the change to quantitative PET and CT measurements when operated at ultralow doses (10–35 mA s). CT quantitation: noise, low-contrast resolution, and CT numbers for 11 tissue substitutes were analyzed in-phantom. CT quantitation was analyzed to a reduction of 90% volume computed tomography dose index (0.39/3.64; mGy) from baseline. To minimize noise infiltration, 100% adaptive statistical iterative reconstruction (ASiR) was used for CT reconstruction. PET images were reconstructed with the lower-dose CTAC iterations and analyzed for: maximum body weight standardized uptake value (SUV{sub bw}) of various diameter targets (range 8–37 mm), background uniformity, and spatial resolution. Radiation dose and CTAC noise magnitude were compared for 140 patient examinations (76 post-ASiR implementation) to determine relative dose reduction and noise control. Results: CT numbers were constant to within 10% from the nondose reduced CTAC image for 90% dose reduction. No change in SUV{sub bw}, background percent uniformity, or spatial resolution for PET images reconstructed with CTAC protocols was found down to 90% dose reduction. Patient population effective dose analysis demonstrated relative CTAC dose reductions between 62% and 86% (3.2/8.3–0.9/6.2). Noise magnitude in dose-reduced patient images increased but was not statistically different from predose-reduced patient images. Conclusions: Using ASiR allowed for aggressive reduction in CT dose with no change in PET reconstructed images while maintaining sufficient image quality for colocalization of hybrid CT anatomy and PET radioisotope uptake.

  18. The technique advantages of 16-detector multic-slice spiral CT in evaluating combined pulmonary and deep vein thromboembolism

    International Nuclear Information System (INIS)

    Xia Shuang; Qi Ji; Lei Xinwei; Wen Lianqing; Li Yiming; Liu Jisheng

    2004-01-01

    Objective: To study the scanning technique of 16-detector multic-slice spiral CT(MSCT) for combined pulmonary artery and deep vein of lower limb in pulmonary thromboembolism (PE) patients. Methods: Forty suspected pulmonary thromboembolism patients were performed both pulmonary artery angiography (CTA) and indirect deep vein venography (CTV) on 16-detector MSCT. The parameters of the latter as following: total contrast volume 120-150 ml, injection rate 4.0-4.5 ml/s (from antecubital vein), delay time 4.0 for CTA 20-23 s, CTV 120-180 s, collimation for CTA 1.25 mm and 0.625 mm, CTV 2.5 mm, scan range of CTV: from popliteal vein to the level of bilateral renal vein into the inferior vena cava. Postprocessing include MPR, MIP, and VR. The test was used to analyzed the images. Results: Twenty five patients had both pulmonary thromboembolism (PE) and deep vein thromboembolism (DVT), 8 patients had only DVT, 2 had only PE, and 5 had neither. There was no difference between different collimation in depicting thrombus. The CT value number of enhanced pulmonary artery and lower deep vein was obviously higher than the thrombus. The value of MPR, MIP, VR for PE was 100%, 100%, and 65%, The value of MPR, MIP, VR for DVT is 100%, 60%, and 50%. Conclusion: The technique of combined pulmonary CTA and deep vein CTV of 16-detector MSCT will provide a new modality for pulmonary thromboembolism patients. (author)

  19. Dose reduction with adaptive statistical iterative reconstruction for paediatric CT: phantom study and clinical experience on chest and abdomen CT

    Energy Technology Data Exchange (ETDEWEB)

    Gay, F.; Lasalle, S.; Neuenschwander, S.; Brisse, H.J. [Institut Curie, Imaging Department, Paris (France); Pavia, Y.; Pierrat, N. [Institut Curie, Medical Physics Department, Paris (France)

    2014-01-15

    To assess the benefit and limits of iterative reconstruction of paediatric chest and abdominal computed tomography (CT). The study compared adaptive statistical iterative reconstruction (ASIR) with filtered back projection (FBP) on 64-channel MDCT. A phantom study was first performed using variable tube potential, tube current and ASIR settings. The assessed image quality indices were the signal-to-noise ratio (SNR), the noise power spectrum, low contrast detectability (LCD) and spatial resolution. A clinical retrospective study of 26 children (M:F = 14/12, mean age: 4 years, range: 1-9 years) was secondarily performed allowing comparison of 18 chest and 14 abdominal CT pairs, one with a routine CT dose and FBP reconstruction, and the other with 30 % lower dose and 40 % ASIR reconstruction. Two radiologists independently compared the images for overall image quality, noise, sharpness and artefacts, and measured image noise. The phantom study demonstrated a significant increase in SNR without impairment of the LCD or spatial resolution, except for tube current values below 30-50 mA. On clinical images, no significant difference was observed between FBP and reduced dose ASIR images. Iterative reconstruction allows at least 30 % dose reduction in paediatric chest and abdominal CT, without impairment of image quality. (orig.)

  20. Dose reduction with adaptive statistical iterative reconstruction for paediatric CT: phantom study and clinical experience on chest and abdomen CT

    International Nuclear Information System (INIS)

    Gay, F.; Lasalle, S.; Neuenschwander, S.; Brisse, H.J.; Pavia, Y.; Pierrat, N.

    2014-01-01

    To assess the benefit and limits of iterative reconstruction of paediatric chest and abdominal computed tomography (CT). The study compared adaptive statistical iterative reconstruction (ASIR) with filtered back projection (FBP) on 64-channel MDCT. A phantom study was first performed using variable tube potential, tube current and ASIR settings. The assessed image quality indices were the signal-to-noise ratio (SNR), the noise power spectrum, low contrast detectability (LCD) and spatial resolution. A clinical retrospective study of 26 children (M:F = 14/12, mean age: 4 years, range: 1-9 years) was secondarily performed allowing comparison of 18 chest and 14 abdominal CT pairs, one with a routine CT dose and FBP reconstruction, and the other with 30 % lower dose and 40 % ASIR reconstruction. Two radiologists independently compared the images for overall image quality, noise, sharpness and artefacts, and measured image noise. The phantom study demonstrated a significant increase in SNR without impairment of the LCD or spatial resolution, except for tube current values below 30-50 mA. On clinical images, no significant difference was observed between FBP and reduced dose ASIR images. Iterative reconstruction allows at least 30 % dose reduction in paediatric chest and abdominal CT, without impairment of image quality. (orig.)

  1. Noninvasive coronary artery imaging by multislice spiral computed tomography. A novel approach for a retrospectively ECG-gated reconstruction technique

    International Nuclear Information System (INIS)

    Sato, Yuichi; Kanmatsuse, Katsuo; Inoue Fumio

    2003-01-01

    Although the excellent spatial resolution of multislice spiral computed tomography (MSCT) enables the coronary arteries to be visualized, its limited temporal resolution results in poor image reproducibility because of cardiac motion artifact (CMA) and hence limits its widespread clinical use. A novel retrospectively electrocardiogram (ECG)-gated reconstruction method has been developed to minimize CMA. In 88 consecutive patients, the scan data were reconstructed using 2 retrospectively ECG-gated reconstruction methods. Method 1: the end of the reconstruction window (250 ms) was positioned at the peak of the P wave on ECG, which corresponded to the end of the slow filling phase during diastole immediately before atrial contraction. Method 2 (conventional method): relative retrospective gating with 50% referred to the R-R interval was performed so that the beginning of the reconstruction window (250 ms) was positioned at the halfway point between the R-R intervals of the heart cycle. The quality of the coronary artery images was evaluated according to the presence or absence of CMA. The assessment was applied to the left main coronary artery (LMCA), the left anterior descending artery (LAD, segments no.6, no.7, and no.8), the left circumflex artery (LCx, segments no.11 and no.13) and the right coronary artery (RCA, segments no.1, no.2 and no.3). The first diagonal artery (no.9-1), the obtuse marginal artery (no.12-1), the posterior descending artery (no.4-PD), the atrioventricular node branch (no.4-AV) and the first right ventricular branch (RV) were also evaluated. Of the 88 patients, 85 were eligible for image evaluation. Method 1 allowed visualization of the major coronary arteries without CMA in the majority of patients. The left coronary artery (LCA) system (segments no.5-7, no.11 and no.13) and the proximal portion of the RCA were visualized in more than 94% of patients. Artifact-free visualization of the distal portion of the LAD (segment no.8) and RCA (no.4

  2. Clinical application of multislice spiral CT angiography in evaluation of anomalous vertebral artery

    International Nuclear Information System (INIS)

    Hua Rui; Liu Jun; Zhang Yu

    2008-01-01

    Objective: To evaluate the diagnostic value of 16-slice spiral computed tomography angiography (MSCTA) in evaluation of anomalous vertebral artery. Methods: MSCTA data from 32 patients with anomalous vertebral artery were retrospectively analyzed. Results: 22 cases had vertebral artery course variation (bended into the C 5 , C 4 or C 3 foramen transversarium), 7 cases had variation in the prevertebral segments of vertebral arteries, 15 patients had unilateral vertebral congenital stenosis, 1 case had double vertebral artery branch, 1 case had vertebral arterial fenestration, and 2 cases had vertebral artery in one side that did not converged upon basilar artery and unilateral vertebral artery formed basilar artery. Conclusion: MSCTA is a useful noninvasive imaging tool for the diagnosis of vertebral artery variations. (authors)

  3. Blunt traumatic rupture of a mainstem bronchus: spiral CT demonstration of the ''fallen lung'' sign

    International Nuclear Information System (INIS)

    Wintermark, M.; Schnyder, P.; Wicky, S.

    2001-01-01

    Tracheo-bronchial injuries occur in less than 1 % of blunt chest trauma patients. Indirect signs, such as pneumomediastinum, pneumothorax, and/or subcutaneous emphysema, are revealed on admission plain films and chest CT survey. In most instances, however, tracheo-bronchoscopy is mandatory in assessing the definite diagnosis of tracheo-bronchial lesion. Occasionally, an abnormal course of a mainstem bronchus or a ''fallen lung'' sign, featuring a collapsed lung in a dependent position, hanging on the hilum only by its vascular attachments, may allow for CT diagnosis of a blunt traumatic bronchial injury. (orig.)

  4. Optimization of Proton CT Detector System and Image Reconstruction Algorithm for On-Line Proton Therapy.

    Directory of Open Access Journals (Sweden)

    Chae Young Lee

    Full Text Available The purposes of this study were to optimize a proton computed tomography system (pCT for proton range verification and to confirm the pCT image reconstruction algorithm based on projection images generated with optimized parameters. For this purpose, we developed a new pCT scanner using the Geometry and Tracking (GEANT 4.9.6 simulation toolkit. GEANT4 simulations were performed to optimize the geometric parameters representing the detector thickness and the distance between the detectors for pCT. The system consisted of four silicon strip detectors for particle tracking and a calorimeter to measure the residual energies of the individual protons. The optimized pCT system design was then adjusted to ensure that the solution to a CS-based convex optimization problem would converge to yield the desired pCT images after a reasonable number of iterative corrections. In particular, we used a total variation-based formulation that has been useful in exploiting prior knowledge about the minimal variations of proton attenuation characteristics in the human body. Examinations performed using our CS algorithm showed that high-quality pCT images could be reconstructed using sets of 72 projections within 20 iterations and without any streaks or noise, which can be caused by under-sampling and proton starvation. Moreover, the images yielded by this CS algorithm were found to be of higher quality than those obtained using other reconstruction algorithms. The optimized pCT scanner system demonstrated the potential to perform high-quality pCT during on-line image-guided proton therapy, without increasing the imaging dose, by applying our CS based proton CT reconstruction algorithm. Further, we make our optimized detector system and CS-based proton CT reconstruction algorithm potentially useful in on-line proton therapy.

  5. Diagnostic value of 3 D CT surface reconstruction in spinal fractures

    Energy Technology Data Exchange (ETDEWEB)

    Koesling, S. [Department of Radiology, Univ. of Leipzig (Germany); Dietrich, K. [Department of Radiology, Univ. of Leipzig (Germany); Steinecke, R. [Department of Radiology, Univ. of Leipzig (Germany); Kloeppel, R. [Department of Radiology, Univ. of Leipzig (Germany); Schulz, H.G. [Department of Radiology, Univ. of Leipzig (Germany)

    1997-02-01

    Our purpose was to evaluate the diagnostic value of three-dimensional (3 D) CT surface reconstruction in spinal fractures in comparison with axial and reformatted images. A total of 50 patients with different CT-proven spinal fractures were analysed retrospectively. Based on axial scans and reformatted images, the spinal fractures were classified according to several classifications as Magerl for the thoraco-lumbar and lower cervical spine by one radiologist. Another radiologist performed 3 D CT surface reconstructions with the aim of characterizing the different types of spinal fractures. A third radiologist classified the 3 D CT surface reconstruction according to the Magerl classification. The results of the blinded reading process were compared. It was checked to see in which type and subgroup 3 D surface reconstructions were helpful. Readers one and two obtained the same results in the classification. The 3 D surface reconstruction did not yield any additional diagnostic information concerning type A and B injuries. Indeed, the full extent of the fracture could be easier recognized with axial and reformatted images in all cases. In 10 cases of C injuries, the dislocation of parts of vertebrae could be better recognized with the help of 3 D reconstructions. A 3 D CT surface reconstruction is only useful in rotational and shear vertebral injuries (Magerl type C injury). (orig.). With 4 figs., 1 tab.

  6. Coronary artery stent imaging with 128-slice dual-source CT using high-pitch spiral acquisition in a cardiac phantom: comparison with the sequential and low-pitch spiral mode

    International Nuclear Information System (INIS)

    Wolf, Florian; Loewe, Christian; Plank, Christina; Schernthaner, Ruediger; Bercaczy, Dominik; Lammer, Johannes; Leschka, Sebastian; Goetti, Robert; Marincek, Borut; Alkadhi, Hatem; Homolka, Peter; Friedrich, Guy; Feuchtner, Gudrun

    2010-01-01

    To evaluate coronary stents in vitro using 128-slice-dual-source computed tomography (CT). Twelve different coronary stents placed in a non-moving cardiac/chest phantom were examined by 128-slice dual-source CT using three CT protocols [high-pitch spiral (HPS), sequential (SEQ) and conventional spiral (SPIR)]. Artificial in-stent lumen narrowing (ALN), visible inner stent area (VIA), artificial in-stent lumen attenuation (ALA) in percent, image noise inside/outside the stent and CTDIvol were measured. Mean ALN was 46% for HPS, 44% for SEQ and 47% for SPIR without significant difference. Mean VIA was similar with 31% for HPS, 30% for SEQ and 33% for SPIR. Mean ALA was, at 5% for HPS, significantly lower compared with -11% for SPIR (p = 0.024), but not different from SEQ with -1%. Mean image noise was significantly higher for HPS compared with SEQ and SPIR inside and outside the stent (p < 0.001). CTDIvol was lower for HPS (5.17 mGy), compared with SEQ (9.02 mGy) and SPIR (55.97 mGy), respectively. The HPS mode of 128-slice dual-source CT yields fewer artefacts inside the stent lumen compared with SPIR and SEQ, but image noise is higher. ALN is still too high for routine stent evaluation in clinical practice. Radiation dose of the HPS mode is markedly (less than about tenfold) reduced. (orig.)

  7. Automatic exposure control to reduce the dose in subsecond multislice spiral CT: phantom measurements and clinical results

    International Nuclear Information System (INIS)

    Greess, H.; Bautz, W.; Baum, U.; Wolf, H.; Suess, C.; Kalender, W.A.

    2004-01-01

    Purpose: To investigate the potential of dose reduction in multislice spiral CT (MSCT) with automatic exposure control. Materials and Methods: The study was performed on a Sensation 4 multislice scanner. This prototype implementation analyzed the distribution of the attenuation along the z-axis in the lateral and sagittal directions of the digital radiogram. Depending on this distribution of the attenuation, the tube current (mA) is defined for every tube rotation. In addition, the tube current was modulated during each tube rotation. First, a three step oval water phantom was measured to evaluate the potential of this method with respect to dose reduction and image quality. In a patient study (n=26), four different scan regions (shoulder, thorax, abdomen, pelvis) were examined and dose (mAs) and image quality evaluated in comparison to examinations with a standard protocol for these regions in adults and a weight-adjusted standard protocol in children. The image quality was classified in consensus as good, sufficient and poor image quality. Results: By adapting and modulating the tube current, we substantially reduced the variation of noise in one spiral scan and in one scan region of our patient collective. The dose (average mAs) was reduced by 31% to 66% in children (mean 44%) and between 35% and 64% in adults (mean 53%), depending on the scan region. The image quality was substantially improved in regions with high attenuation and did not suffer in low attenuation regions. Conclusion: The dose can be reduced substantially by an automatic exposure control including angular tube current modulation with the same or improved image quality. (orig.) [de

  8. Use of spiral CT and the contrast medium iohexol to determine in one session aortorenal morphology and the relative glomerular filtration rate of each kidney

    International Nuclear Information System (INIS)

    Frennby, B.; Almen, T.

    2001-01-01

    The aim of this study was to determine the relative glomerular filtration rate (GFR), i.e. the GFR of each kidney in percent of total GFR, by spiral CT. In 41 patients, who were part of a follow-up program after endoluminal stent grafting of aortic aneurysm, spiral CT with the contrast medium iohexol was used to evaluate the morphology of the aorta and kidneys. The opportunity was taken to utilize the already injected iohexol to determine the relative GFR with an extra CT sequence. In each patient two determinations were made, 6 or 12 months apart. The amount of a GFR marker accumulating in Bowman's space, tubuli, and renal pelvis within 2-3 min after i.v. injection, before any marker had left the kidney via the ureter, was defined as proportional to the GFR of that kidney. The renal accumulation of iohexol was obtained by spiral CT using 10-mm collimation and a table speed of 10 mm/s (pitch ratio 1:1) from the upper to the lower poles. The correlation coefficient between the relative GFR of each kidney determined at the first and second examination was excellent (r=0.99) with a median (range) difference of 1% (0-6%) of total GFR. The radiation dose calculated as the mean absorbed dose to the kidneys was 50 mGy and the effective dose 5 mSv. The morphology of aorta and kidneys and the relative GFR of each kidney can be determined in one session with spiral CT using iohexol as both angiographic contrast medium and as a GFR marker. It is also possible to take some plasma samples in the same session to determine iohexol concentration to calculate the body clearance of iohexol (or take plasma and urine samples to calculate the renal clearance of iohexol). (orig.)

  9. Optimization of CT image reconstruction algorithms for the lung tissue research consortium (LTRC)

    Science.gov (United States)

    McCollough, Cynthia; Zhang, Jie; Bruesewitz, Michael; Bartholmai, Brian

    2006-03-01

    To create a repository of clinical data, CT images and tissue samples and to more clearly understand the pathogenetic features of pulmonary fibrosis and emphysema, the National Heart, Lung, and Blood Institute (NHLBI) launched a cooperative effort known as the Lung Tissue Resource Consortium (LTRC). The CT images for the LTRC effort must contain accurate CT numbers in order to characterize tissues, and must have high-spatial resolution to show fine anatomic structures. This study was performed to optimize the CT image reconstruction algorithms to achieve these criteria. Quantitative analyses of phantom and clinical images were conducted. The ACR CT accreditation phantom containing five regions of distinct CT attenuations (CT numbers of approximately -1000 HU, -80 HU, 0 HU, 130 HU and 900 HU), and a high-contrast spatial resolution test pattern, was scanned using CT systems from two manufacturers (General Electric (GE) Healthcare and Siemens Medical Solutions). Phantom images were reconstructed using all relevant reconstruction algorithms. Mean CT numbers and image noise (standard deviation) were measured and compared for the five materials. Clinical high-resolution chest CT images acquired on a GE CT system for a patient with diffuse lung disease were reconstructed using BONE and STANDARD algorithms and evaluated by a thoracic radiologist in terms of image quality and disease extent. The clinical BONE images were processed with a 3 x 3 x 3 median filter to simulate a thicker slice reconstructed in smoother algorithms, which have traditionally been proven to provide an accurate estimation of emphysema extent in the lungs. Using a threshold technique, the volume of emphysema (defined as the percentage of lung voxels having a CT number lower than -950 HU) was computed for the STANDARD, BONE, and BONE filtered. The CT numbers measured in the ACR CT Phantom images were accurate for all reconstruction kernels for both manufacturers. As expected, visual evaluation of the

  10. Influence of iterative image reconstruction on CT-based calcium score measurements

    NARCIS (Netherlands)

    van Osch, Jochen A. C.; Mouden, Mohamed; van Dalen, Jorn A.; Timmer, Jorik R.; Reiffers, Stoffer; Knollema, Siert; Greuter, Marcel J. W.; Ottervanger, Jan Paul; Jager, Piet L.

    Iterative reconstruction techniques for coronary CT angiography have been introduced as an alternative for traditional filter back projection (FBP) to reduce image noise, allowing improved image quality and a potential for dose reduction. However, the impact of iterative reconstruction on the

  11. Postoperative assessment of surgical results using three dimensional surface reconstruction CT (3D-CT) in a craniofacial anomaly

    International Nuclear Information System (INIS)

    Nishimura, Jiro; Sato, Kaoru; Nishimoto, Hiroshi; Tsukiyama, Takashi; Fujioka, Mutsuhisa; Akagawa, Tetsuya.

    1988-01-01

    In 1983, Michael W. Vannier and Jeffrey L. Marsh developed a computer method that reconstructs three dimensional (3D) born and soft tissue surfaces, given a high resolution CT scan-series of the facial skeleton. This method has been applied to craniofacial anomalies, basal encephaloceles, and musculoskeletal anomalies. In this study, a postoperative assessment of the craniofacial surgical results has been accomplished using this 3D-CT in 2 children with craniofacial dysmorphism. The authors discuss the advantages of this 3D-CT imaging method in the postoperative assessments of craniofacial anomalies. Results are detailed in the following listing : 1) a postoperative 3D-CT reveals the anatomical details corrected by the craniofacial surgery more precisely and stereographically than conventional radiological methods ; 2) secondary changes of the cranium after the surgery, such as bony formation in the area of the osteotomy and postoperative asymmetric deformities, are detected early by the 3D-CT imaging technique, and, 3) 3D-CT mid-sagittal and top axial views of the intracranial skull base are most useful in postoperative assessments of the surgical results. Basesd on our experience, we expect that three dimensional surface reconstructions from CT scans will become to be used widely in the postoperative assessments of the surgical results of craniofacial anomalies. (author)

  12. Region-of-interest reconstruction for a cone-beam dental CT with a circular trajectory

    International Nuclear Information System (INIS)

    Hu, Zhanli; Zou, Jing; Gui, Jianbao; Zheng, Hairong; Xia, Dan

    2013-01-01

    Dental CT is the most appropriate and accurate device for preoperative evaluation of dental implantation. It can demonstrate the quantity of bone in three dimensions (3D), the location of important adjacent anatomic structures and the quality of available bone with minimal geometric distortion. Nevertheless, with the rapid increase of dental CT examinations, we are facing the problem of dose reduction without loss of image quality. In this work, backprojection-filtration (BPF) and Feldkamp–Davis–Kress (FDK) algorithm was applied to reconstruct the 3D full image and region-of-interest (ROI) image from complete and truncated circular cone-beam data respectively by computer-simulation. In addition, the BPF algorithm was evaluated based on the 3D ROI-image reconstruction from real data, which was acquired from our developed circular cone-beam prototype dental CT system. The results demonstrated that the ROI-image quality reconstructed from truncated data using the BPF algorithm was comparable to that reconstructed from complete data. The FDK algorithm, however, created artifacts while reconstructing ROI-image. Thus it can be seen, for circular cone-beam dental CT, reducing scanning angular range of the BPF algorithm used for ROI-image reconstruction are helpful for reducing the radiation dose and scanning time. Finally, an analytical method was developed for estimation of the ROI projection area on the detector before CT scanning, which would help doctors to roughly estimate the total radiation dose before the CT examination. -- Highlights: ► BPF algorithm was applied by using dental CT for the first time. ► A method was developed for estimation of projection region before CT scanning. ► Roughly predict the total radiation dose before CT scans. ► Potential reduce imaging radiation dose, scatter, and scanning time

  13. CT pulmonary angiography using 64-row multi-slice spiral CT: a comparative study in low tube voltage setting combined with personalized contrast agent application

    International Nuclear Information System (INIS)

    Zhou Xuhui; Peng Zhenpeng; Zheng Lili; Li Shurong; Yang Zhiyun; Meng Quanfei; Chen Xing

    2009-01-01

    Objective: To investigate the feasibility of the low tube voltage setting and personalized contrast agent application in 64-row multi-slice spiral CT pulmonary angiography. Methods: Ninety patients with high risk of pulmonary artery embolism were sequentially enrolled in the study and divided into 3 groups employing completely randomized design: (l)Regular group included 30 patients using 120 kV and fixed dose of 70 ml contrast agent, (2)Another 30 patients were in 120 kV group, using 120 kV and the contrast amount was determined according to the patient weight (1.0 ml/kg), (3) The remaining 30 patients were included in 100 kV group, using 100 kV and the contrast amount was also determined according to the patient weight(1.0 ml/kg). Administration of contrast agent was completed within 20 seconds for all the patients, followed by 20 ml of saline. The objective and subjective indexes for assessing CT image quality, CT dose index volume (CTDIvol) and effective received dose (ERD) were compared between 120 kV group and 100 kV group; then the contrast media volume, injection rate, objective CT image indexes and subjective indexes for image quality was compared between the 100 kV group and regular group. The variance analysis and post hoc test were employed for the statistical analysis. Results: Compared with 120 kV group (3.4±0.7), the image quality of 100 kV group (5.2±1.8) had higher noise (52.9%), but subjective index for the image quality demonstrated no differences (q=0.272, P=0.063) in mediastinum window while CTDIvol and ERD decreased for 34.9% [(9.5±0.0) vs (14.6±0.0) mGy] and 36.8% [(3.8±0.6) vs (2.4±0.4) mSv]. The mean CT values on pulmonary artery of 100 kV group[ (269.2±54.7) HU] were 13.4% (31.8/237.4) higher than the 120 kV group [(237.4±62.9)HU], but there was no statistical differences compared to normal group (q=0.172,P=0.260). Conclusion: Using low kV setting (100 kV) to reduce radiation dose is proved to be effective and feasible in 64-MSCT

  14. Pulmonary embolism: Prospective comparison of spiral CT with ventilation - perfusion scintigraphy

    International Nuclear Information System (INIS)

    Mayo Jhon R; Remi Jardin, Martine; Muller Mestor I

    1999-01-01

    The pulmonary thromboembolism (PTE) it is an entity common with great morbidity and mortality that it requires a diagnosis soon and specify. Commonly the ventilation gammagraphy - perfusion has been the used exam of first more frequent line when one suspects the PTE but unfortunately a great quantity of reports is called of intermediate probability, for what requires complementary studies, to confirm or to discard the diagnosis. A prospective study was made with 142 patients that had suspicion of TEP in the hospital of Vancouver (Canada) and in the hospital of Calmette (France), being carried out in all gammagraphy of ventilation-perfusion and helical CT, being only taken to lung angiography to those that not had high clinical suspicion of TEP with gammagraphy or helical CT very suggestive or tuneless, undergoing the results valuation for different observers

  15. Dose reduction using prospective electrocardiograph-triggered axial coronary scan on the 64-slice spiral CT

    International Nuclear Information System (INIS)

    Wang Yanyan; Wu Guogeng; Zhou Cheng; Gao Jianhua; Jiao Sheng; Cao Huizhi

    2008-01-01

    Objective: To compare radiation dose and image quality between prospective electrocardiograph (ECG)-triggered axial scan and retrospective ECG-gated helical scan in coronary 64-slice CT angiography (CTA). Methods: Seventy-seven consecutive patients [group A. Average body mass index (BMI): 24.6, heart rate 0.05). Conclusion: Prospective ECG-triggered axial scan in 64-slice coronary CTA can significantly reduce radiation exposure and the image quality can fulfill clinical diagnostic needs. (authors)

  16. Application status of three-dimensional CT reconstruction in hepatobiliary surgery

    Directory of Open Access Journals (Sweden)

    JIANG Chao

    2017-02-01

    Full Text Available With the development of imaging technology, three-dimensional CT reconstruction has been widely used in hepatobiliary surgery. Three-dimensional CT reconstruction can divide and reconstruct two-dimensional images into three-dimensional images and clearly show the location of lesion and its relationship with the intrahepatic bile duct system. It has an important value in the preoperative assessment of liver volume, diagnosis and treatment decision-making process, intraoperative precise operation, and postoperative individualized management, and promotes the constant development of hepatobiliary surgery and minimally invasive technology, and therefore, it holds promise for clinical application.

  17. Accuracy improvement of CT reconstruction using tree-structured filter bank

    International Nuclear Information System (INIS)

    Ueda, Kazuhiro; Morimoto, Hiroaki; Morikawa, Yoshitaka; Murakami, Junichi

    2009-01-01

    Accuracy improvement of 'CT reconstruction algorithm using TSFB (Tree-Structured Filter Bank)' that is high-speed CT reconstruction algorithm, was proposed. TSFB method could largely reduce the amount of computation in comparison with the CB (Convolution Backprojection) method, but it was the problem that an artifact occurred in a reconstruction image since reconstruction was performed with disregard to a signal out of the reconstruction domain in stage processing. Also the whole band filter being the component of a two-dimensional synthesis filter was IIR filter and then an artifact occurred at the end of the reconstruction image. In order to suppress these artifacts the proposed method enlarged the processing range by the TSFB method in the domain outside by the width control of the specimen line and line addition to the reconstruction domain outside. And, furthermore, to avoid increase of the amount of computation, the algorithm was proposed such as to decide the needed processing range depending on the number of steps processing with the TSFB and the degree of incline of filter, and then update the position and width of the specimen line to process the needed range. According to the simulation to realize a high-speed and highly accurate CT reconstruction in this way, the quality of the reconstruction image of the proposed method was improved in comparison with the TSFB method and got the same result with the CB method. (T. Tanaka)

  18. Spectral CT metal artifact reduction with an optimization-based reconstruction algorithm

    Science.gov (United States)

    Gilat Schmidt, Taly; Barber, Rina F.; Sidky, Emil Y.

    2017-03-01

    Metal objects cause artifacts in computed tomography (CT) images. This work investigated the feasibility of a spectral CT method to reduce metal artifacts. Spectral CT acquisition combined with optimization-based reconstruction is proposed to reduce artifacts by modeling the physical effects that cause metal artifacts and by providing the flexibility to selectively remove corrupted spectral measurements in the spectral-sinogram space. The proposed Constrained `One-Step' Spectral CT Image Reconstruction (cOSSCIR) algorithm directly estimates the basis material maps while enforcing convex constraints. The incorporation of constraints on the reconstructed basis material maps is expected to mitigate undersampling effects that occur when corrupted data is excluded from reconstruction. The feasibility of the cOSSCIR algorithm to reduce metal artifacts was investigated through simulations of a pelvis phantom. The cOSSCIR algorithm was investigated with and without the use of a third basis material representing metal. The effects of excluding data corrupted by metal were also investigated. The results demonstrated that the proposed cOSSCIR algorithm reduced metal artifacts and improved CT number accuracy. For example, CT number error in a bright shading artifact region was reduced from 403 HU in the reference filtered backprojection reconstruction to 33 HU using the proposed algorithm in simulation. In the dark shading regions, the error was reduced from 1141 HU to 25 HU. Of the investigated approaches, decomposing the data into three basis material maps and excluding the corrupted data demonstrated the greatest reduction in metal artifacts.

  19. An Approximate Cone Beam Reconstruction Algorithm for Gantry-Tilted CT Using Tangential Filtering

    Directory of Open Access Journals (Sweden)

    Ming Yan

    2006-01-01

    Full Text Available FDK algorithm is a well-known 3D (three-dimensional approximate algorithm for CT (computed tomography image reconstruction and is also known to suffer from considerable artifacts when the scanning cone angle is large. Recently, it has been improved by performing the ramp filtering along the tangential direction of the X-ray source helix for dealing with the large cone angle problem. In this paper, we present an FDK-type approximate reconstruction algorithm for gantry-tilted CT imaging. The proposed method improves the image reconstruction by filtering the projection data along a proper direction which is determined by CT parameters and gantry-tilted angle. As a result, the proposed algorithm for gantry-tilted CT reconstruction can provide more scanning flexibilities in clinical CT scanning and is efficient in computation. The performance of the proposed algorithm is evaluated with turbell clock phantom and thorax phantom and compared with FDK algorithm and a popular 2D (two-dimensional approximate algorithm. The results show that the proposed algorithm can achieve better image quality for gantry-tilted CT image reconstruction.

  20. Spiral CT angiography (SCTA) study of celiac artery and superior mesenteric artery

    International Nuclear Information System (INIS)

    Yuan Zhenguo; Zhou Cunsheng; Xu Zuodong; Shi Hao; Wang Tao

    1999-01-01

    Objective: To study the visualization capability and scanning technique of SCTA in celiac artery, superior mesenteric artery (SMA) and other branches. Methods: Thirty patients, with normal abdominal SCTA results, were given small injection test dose after plain scan. The abdominal aorta parallel to the body of pancreas was chosen as target vessel, the peak-time plus 2 seconds as the best delay scan time. Iodine contrast medium 90∼110 ml was injected into antecubital vein at the speed of 3.5 ml/s, then scan from cranial to caudal was performed. Pitch 1.0 and slice thickness 3.2 mm were selected as the scan parameters. Maximum intensity projection (MaxIP) was employed in all patients and shaded surface display (SSD) in 23 cases. Results: The display rate using MaxIP and SSD of celiac artery, splenic artery, common hepatic artery, proper hepatic artery and SMA were all 100%, the gastroduodenal artery 100% and 91%, the left gastric artery 83% and 87%, respectively. Conclusions: SCTA as a minimally invasive examination is a valuable method to detect and diagnose disease or variations of celiac artery, its branches and SMA. Spiral scanning technique and image processing have a decisive effect on the image quality

  1. Adaptive statistical iterative reconstruction reduces patient radiation dose in neuroradiology CT studies

    Energy Technology Data Exchange (ETDEWEB)

    Komlosi, Peter; Zhang, Yanrong; Leiva-Salinas, Carlos; Ornan, David; Grady, Deborah [University of Virginia, Department of Radiology and Medical Imaging, Division of Neuroradiology, PO Box 800170, Charlottesville, VA (United States); Patrie, James T.; Xin, Wenjun [University of Virginia, Department of Public Health Sciences, Charlottesville, VA (United States); Wintermark, Max [University of Virginia, Department of Radiology and Medical Imaging, Division of Neuroradiology, PO Box 800170, Charlottesville, VA (United States); Centre Hospitalier Universitaire Vaudois, Department of Radiology, Lausanne (Switzerland)

    2014-03-15

    Adaptive statistical iterative reconstruction (ASIR) can decrease image noise, thereby generating CT images of comparable diagnostic quality with less radiation. The purpose of this study is to quantify the effect of systematic use of ASIR versus filtered back projection (FBP) for neuroradiology CT protocols on patients' radiation dose and image quality. We evaluated the effect of ASIR on six types of neuroradiologic CT studies: adult and pediatric unenhanced head CT, adult cervical spine CT, adult cervical and intracranial CT angiography, adult soft tissue neck CT with contrast, and adult lumbar spine CT. For each type of CT study, two groups of 100 consecutive studies were retrospectively reviewed: 100 studies performed with FBP and 100 studies performed with ASIR/FBP blending factor of 40 %/60 % with appropriate noise indices. The weighted volume CT dose index (CTDI{sub vol}), dose-length product (DLP) and noise were recorded. Each study was also reviewed for image quality by two reviewers. Continuous and categorical variables were compared by t test and free permutation test, respectively. For adult unenhanced brain CT, CT cervical myelography, cervical and intracranial CT angiography and lumbar spine CT both CTDI{sub vol} and DLP were lowered by up to 10.9 % (p < 0.001), 17.9 % (p = 0.005), 20.9 % (p < 0.001), and 21.7 % (p = 0.001), respectively, by using ASIR compared with FBP alone. Image quality and noise were similar for both FBP and ASIR. We recommend routine use of iterative reconstruction for neuroradiology CT examinations because this approach affords a significant dose reduction while preserving image quality. (orig.)

  2. Adaptive statistical iterative reconstruction reduces patient radiation dose in neuroradiology CT studies

    International Nuclear Information System (INIS)

    Komlosi, Peter; Zhang, Yanrong; Leiva-Salinas, Carlos; Ornan, David; Grady, Deborah; Patrie, James T.; Xin, Wenjun; Wintermark, Max

    2014-01-01

    Adaptive statistical iterative reconstruction (ASIR) can decrease image noise, thereby generating CT images of comparable diagnostic quality with less radiation. The purpose of this study is to quantify the effect of systematic use of ASIR versus filtered back projection (FBP) for neuroradiology CT protocols on patients' radiation dose and image quality. We evaluated the effect of ASIR on six types of neuroradiologic CT studies: adult and pediatric unenhanced head CT, adult cervical spine CT, adult cervical and intracranial CT angiography, adult soft tissue neck CT with contrast, and adult lumbar spine CT. For each type of CT study, two groups of 100 consecutive studies were retrospectively reviewed: 100 studies performed with FBP and 100 studies performed with ASIR/FBP blending factor of 40 %/60 % with appropriate noise indices. The weighted volume CT dose index (CTDI vol ), dose-length product (DLP) and noise were recorded. Each study was also reviewed for image quality by two reviewers. Continuous and categorical variables were compared by t test and free permutation test, respectively. For adult unenhanced brain CT, CT cervical myelography, cervical and intracranial CT angiography and lumbar spine CT both CTDI vol and DLP were lowered by up to 10.9 % (p < 0.001), 17.9 % (p = 0.005), 20.9 % (p < 0.001), and 21.7 % (p = 0.001), respectively, by using ASIR compared with FBP alone. Image quality and noise were similar for both FBP and ASIR. We recommend routine use of iterative reconstruction for neuroradiology CT examinations because this approach affords a significant dose reduction while preserving image quality. (orig.)

  3. Evaluation of the OSC-TV iterative reconstruction algorithm for cone-beam optical CT.

    Science.gov (United States)

    Matenine, Dmitri; Mascolo-Fortin, Julia; Goussard, Yves; Després, Philippe

    2015-11-01

    The present work evaluates an iterative reconstruction approach, namely, the ordered subsets convex (OSC) algorithm with regularization via total variation (TV) minimization in the field of cone-beam optical computed tomography (optical CT). One of the uses of optical CT is gel-based 3D dosimetry for radiation therapy, where it is employed to map dose distributions in radiosensitive gels. Model-based iterative reconstruction may improve optical CT image quality and contribute to a wider use of optical CT in clinical gel dosimetry. This algorithm was evaluated using experimental data acquired by a cone-beam optical CT system, as well as complementary numerical simulations. A fast GPU implementation of OSC-TV was used to achieve reconstruction times comparable to those of conventional filtered backprojection. Images obtained via OSC-TV were compared with the corresponding filtered backprojections. Spatial resolution and uniformity phantoms were scanned and respective reconstructions were subject to evaluation of the modulation transfer function, image uniformity, and accuracy. The artifacts due to refraction and total signal loss from opaque objects were also studied. The cone-beam optical CT data reconstructions showed that OSC-TV outperforms filtered backprojection in terms of image quality, thanks to a model-based simulation of the photon attenuation process. It was shown to significantly improve the image spatial resolution and reduce image noise. The accuracy of the estimation of linear attenuation coefficients remained similar to that obtained via filtered backprojection. Certain image artifacts due to opaque objects were reduced. Nevertheless, the common artifact due to the gel container walls could not be eliminated. The use of iterative reconstruction improves cone-beam optical CT image quality in many ways. The comparisons between OSC-TV and filtered backprojection presented in this paper demonstrate that OSC-TV can potentially improve the rendering of

  4. Iterative reconstruction technique with reduced volume CT dose index: diagnostic accuracy in pediatric acute appendicitis

    International Nuclear Information System (INIS)

    Didier, Ryne A.; Vajtai, Petra L.; Hopkins, Katharine L.

    2015-01-01

    Iterative reconstruction technique has been proposed as a means of reducing patient radiation dose in pediatric CT. Yet, the effect of such reductions on diagnostic accuracy has not been thoroughly evaluated. This study compares accuracy of diagnosing pediatric acute appendicitis using contrast-enhanced abdominopelvic CT scans performed with traditional pediatric weight-based protocols and filtered back projection reconstruction vs. a filtered back projection/iterative reconstruction technique blend with reduced volume CT dose index (CTDI vol ). Results of pediatric contrast-enhanced abdominopelvic CT scans done for pain and/or suspected appendicitis were reviewed in two groups: A, 192 scans performed with the hospital's established weight-based CT protocols and filtered back projection reconstruction; B, 194 scans performed with iterative reconstruction technique and reduced CTDI vol . Reduced CTDI vol was achieved primarily by reductions in effective tube current-time product (mAs eff ) and tube peak kilovoltage (kVp). CT interpretation was correlated with clinical follow-up and/or surgical pathology. CTDI vol , size-specific dose estimates (SSDE) and performance characteristics of the two CT techniques were then compared. Between groups A and B, mean CTDI vol was reduced by 45%, and mean SSDE was reduced by 46%. Sensitivity, specificity and diagnostic accuracy were 96%, 97% and 96% in group A vs. 100%, 99% and 99% in group B. Accuracy in diagnosing pediatric acute appendicitis was maintained in contrast-enhanced abdominopelvic CT scans that incorporated iterative reconstruction technique, despite reductions in mean CTDI vol and SSDE by nearly half as compared to the hospital's traditional weight-based protocols. (orig.)

  5. Iterative reconstruction technique with reduced volume CT dose index: diagnostic accuracy in pediatric acute appendicitis

    Energy Technology Data Exchange (ETDEWEB)

    Didier, Ryne A. [Oregon Health and Science University, Department of Diagnostic Radiology, DC7R, Portland, OR (United States); Vajtai, Petra L. [Oregon Health and Science University, Department of Pediatrics, Portland, OR (United States); Oregon Health and Science University, Department of Diagnostic Radiology, DC7R, Portland, OR (United States); Hopkins, Katharine L. [Oregon Health and Science University, Department of Diagnostic Radiology, DC7R, Portland, OR (United States); Oregon Health and Science University, Department of Pediatrics, Portland, OR (United States)

    2014-07-05

    Iterative reconstruction technique has been proposed as a means of reducing patient radiation dose in pediatric CT. Yet, the effect of such reductions on diagnostic accuracy has not been thoroughly evaluated. This study compares accuracy of diagnosing pediatric acute appendicitis using contrast-enhanced abdominopelvic CT scans performed with traditional pediatric weight-based protocols and filtered back projection reconstruction vs. a filtered back projection/iterative reconstruction technique blend with reduced volume CT dose index (CTDI{sub vol}). Results of pediatric contrast-enhanced abdominopelvic CT scans done for pain and/or suspected appendicitis were reviewed in two groups: A, 192 scans performed with the hospital's established weight-based CT protocols and filtered back projection reconstruction; B, 194 scans performed with iterative reconstruction technique and reduced CTDI{sub vol}. Reduced CTDI{sub vol} was achieved primarily by reductions in effective tube current-time product (mAs{sub eff}) and tube peak kilovoltage (kVp). CT interpretation was correlated with clinical follow-up and/or surgical pathology. CTDI{sub vol}, size-specific dose estimates (SSDE) and performance characteristics of the two CT techniques were then compared. Between groups A and B, mean CTDI{sub vol} was reduced by 45%, and mean SSDE was reduced by 46%. Sensitivity, specificity and diagnostic accuracy were 96%, 97% and 96% in group A vs. 100%, 99% and 99% in group B. Accuracy in diagnosing pediatric acute appendicitis was maintained in contrast-enhanced abdominopelvic CT scans that incorporated iterative reconstruction technique, despite reductions in mean CTDI{sub vol} and SSDE by nearly half as compared to the hospital's traditional weight-based protocols. (orig.)

  6. Accuracy and reliability of thyroid volumetry using spiral CT and thyroid volume in a healthy, non-iodine-deficient Chinese adult population

    Energy Technology Data Exchange (ETDEWEB)

    Shu Jian, E-mail: shujiannc@163.com [Department of Radiology, Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing 400010 (China); Zhao Jiannong, E-mail: zhaojiannong@tom.com [Department of Radiology, Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing 400010 (China); Guo Dajing, E-mail: guodaj@163.com [Department of Radiology, Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing 400010 (China); Luo Yindeng, E-mail: yindengluo_1019@163.com [Department of Radiology, Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing 400010 (China); Zhong Weijia, E-mail: zhongweijia2003@eyou.com [Department of Radiology, Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing 400010 (China); Xie Weibo, E-mail: radiologycq@163.com [Department of Radiology, Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing 400010 (China)

    2011-02-15

    Objective: The purpose of this study was to assess the accuracy and reliability of thyroid volumetry using spiral CT and to investigate thyroid volumes for a healthy, non-iodine-deficient adult population in southwestern region of China. Materials and methods: Spiral CT was performed in phantoms and adult subjects with normal thyroid, and the volumes were measured by observers with 5 years or more of CT experience. The phantom volumes and the thyroid volumes of all subjects were noted. Results: For the thyroid phantoms, there was no significant difference between the true and CT calculated volumes (t = 0.862, P = 0.399), and the correlation was excellent (ICC = 0.9995, P = 0.000). In the subjects for reliability analysis, the intraobserver or interobserver differences for CT volumetric measurement of thyroid were not significant (P > 0.05). The intraobserver or interobserver correlations were very high (ICC > 0.99, P < 0.001). In the subjects for population analysis, the median of the thyroid volumes was 11.45 cm{sup 3}. The nonparametric Mann-Whitney U-test showed no significant difference for the thyroid volume between sexes (U = 4388.00, Z = -1.118, P = 0.264). The nonparametric Kruskall-Wallis test showed no significant difference in all age groups ({chi}{sup 2} = 13.466, P = 0.062). There was a slight negative correlation between the thyroid volume and age (r{sub s} = -0.166, P = 0.019). Conclusion: The accuracy and reliability of multi-slice spiral CT in measuring thyroid volume are very high. The thyroid volumes are not significantly difference between genders or among decades for the healthy, non-iodine-deficient adult population in southwestern region of China.

  7. Model-based iterative reconstruction and adaptive statistical iterative reconstruction: dose-reduced CT for detecting pancreatic calcification

    International Nuclear Information System (INIS)

    Yasaka, Koichiro; Katsura, Masaki; Akahane, Masaaki; Sato, Jiro; Matsuda, Izuru; Ohtomo, Kuni

    2016-01-01

    Iterative reconstruction methods have attracted attention for reducing radiation doses in computed tomography (CT). To investigate the detectability of pancreatic calcification using dose-reduced CT reconstructed with model-based iterative construction (MBIR) and adaptive statistical iterative reconstruction (ASIR). This prospective study approved by Institutional Review Board included 85 patients (57 men, 28 women; mean age, 69.9 years; mean body weight, 61.2 kg). Unenhanced CT was performed three times with different radiation doses (reference-dose CT [RDCT], low-dose CT [LDCT], ultralow-dose CT [ULDCT]). From RDCT, LDCT, and ULDCT, images were reconstructed with filtered-back projection (R-FBP, used for establishing reference standard), ASIR (L-ASIR), and MBIR and ASIR (UL-MBIR and UL-ASIR), respectively. A lesion (pancreatic calcification) detection test was performed by two blinded radiologists with a five-point certainty level scale. Dose-length products of RDCT, LDCT, and ULDCT were 410, 97, and 36 mGy-cm, respectively. Nine patients had pancreatic calcification. The sensitivity for detecting pancreatic calcification with UL-MBIR was high (0.67–0.89) compared to L-ASIR or UL-ASIR (0.11–0.44), and a significant difference was seen between UL-MBIR and UL-ASIR for one reader (P = 0.014). The area under the receiver-operating characteristic curve for UL-MBIR (0.818–0.860) was comparable to that for L-ASIR (0.696–0.844). The specificity was lower with UL-MBIR (0.79–0.92) than with L-ASIR or UL-ASIR (0.96–0.99), and a significant difference was seen for one reader (P < 0.01). In UL-MBIR, pancreatic calcification can be detected with high sensitivity, however, we should pay attention to the slightly lower specificity

  8. Model-based iterative reconstruction and adaptive statistical iterative reconstruction: dose-reduced CT for detecting pancreatic calcification.

    Science.gov (United States)

    Yasaka, Koichiro; Katsura, Masaki; Akahane, Masaaki; Sato, Jiro; Matsuda, Izuru; Ohtomo, Kuni

    2016-01-01

    Iterative reconstruction methods have attracted attention for reducing radiation doses in computed tomography (CT). To investigate the detectability of pancreatic calcification using dose-reduced CT reconstructed with model-based iterative construction (MBIR) and adaptive statistical iterative reconstruction (ASIR). This prospective study approved by Institutional Review Board included 85 patients (57 men, 28 women; mean age, 69.9 years; mean body weight, 61.2 kg). Unenhanced CT was performed three times with different radiation doses (reference-dose CT [RDCT], low-dose CT [LDCT], ultralow-dose CT [ULDCT]). From RDCT, LDCT, and ULDCT, images were reconstructed with filtered-back projection (R-FBP, used for establishing reference standard), ASIR (L-ASIR), and MBIR and ASIR (UL-MBIR and UL-ASIR), respectively. A lesion (pancreatic calcification) detection test was performed by two blinded radiologists with a five-point certainty level scale. Dose-length products of RDCT, LDCT, and ULDCT were 410, 97, and 36 mGy-cm, respectively. Nine patients had pancreatic calcification. The sensitivity for detecting pancreatic calcification with UL-MBIR was high (0.67-0.89) compared to L-ASIR or UL-ASIR (0.11-0.44), and a significant difference was seen between UL-MBIR and UL-ASIR for one reader (P = 0.014). The area under the receiver-operating characteristic curve for UL-MBIR (0.818-0.860) was comparable to that for L-ASIR (0.696-0.844). The specificity was lower with UL-MBIR (0.79-0.92) than with L-ASIR or UL-ASIR (0.96-0.99), and a significant difference was seen for one reader (P < 0.01). In UL-MBIR, pancreatic calcification can be detected with high sensitivity, however, we should pay attention to the slightly lower specificity.

  9. In-line phase contrast micro-CT reconstruction for biomedical specimens.

    Science.gov (United States)

    Fu, Jian; Tan, Renbo

    2014-01-01

    X-ray phase contrast micro computed tomography (micro-CT) can non-destructively provide the internal structure information of soft tissues and low atomic number materials. It has become an invaluable analysis tool for biomedical specimens. Here an in-line phase contrast micro-CT reconstruction technique is reported, which consists of a projection extraction method and the conventional filter back-projection (FBP) reconstruction algorithm. The projection extraction is implemented by applying the Fourier transform to the forward projections of in-line phase contrast micro-CT. This work comprises a numerical study of the method and its experimental verification using a biomedical specimen dataset measured at an X-ray tube source micro-CT setup. The numerical and experimental results demonstrate that the presented technique can improve the imaging contrast of biomedical specimens. It will be of interest for a wide range of in-line phase contrast micro-CT applications in medicine and biology.

  10. Choice ofoptimal phase for liver angiography and multi-phase scanning with multi-slice spiral CT

    International Nuclear Information System (INIS)

    Fang Hong; Song Yunlong; Bi Yongmin; Wang Dong; Shi Huiping; Zhang Wanshi; Zhu Hongxian; Yang Hua; Ji Xudong; Fan Hongxia

    2008-01-01

    Objective: To evaluate the efficacy of test bolus technique with multi-slice spiral CT (MSCT) for determining the optimal scan delay time in CT Hepatic artery (HA)-portal vein (PV) angiography and multi-phase scanning. Methods: MSCT liver angiography and multi-phase scanning were performed in 187 patients divided randomly into two groups. In group A (n=59), the scan delay time was set according to the subjective experiences of operators; in group B (n=128), the scan delay time was determined by test bolus technique. Abdominal aorta and superior mesenteric, vein were selected as target blood vessels, and 50 HU was set as enhancement threshold value. 20 ml contrast agent was injected intravenously and time-density curve of target blood vessels were obtained, then HA-PV scanning delay time were calculated respectively. The quality of CTA images obtained by using these 2 methods were compared and statistically analysed using Chi-square criterion. Results: For hepatic artery phase, the images of group A are: excellent in 34 (58%), good in 17 (29%), and poor in 8 (13%), while those of group B are excellent in 128(100%), good in 0(0%), and poor in 0(0%). For portal vein phase, the images of group A are: excellent in 23 (39%), good in 27 (46%), and poor in 9 (15%), while those of group B are excellent in 96 (75%), good in 28 (22%), and poor in 4 (3%) respectively. There was statistically significant difference between the ratios of image quality in group A and group B (χ 2 =14.97, 9.18, P< 0.05). Conclusion: Accurate scan delay time was best determined by using test bolus technique, which can improve the image quality of liver angiography and multi-phase scanning. (authors)

  11. Comparative study of multi-slice spiral CT angiography and color doppler ultrasound in diagnosis of arteriosclerotic occlusive disease of lower extremity

    International Nuclear Information System (INIS)

    Li Wanjun; Lai Zhenhui; Cui Dong; Lin Xiupeng; Du Muxuan

    2010-01-01

    Objective: To compare the difference between multi-slice spiral CT angiography (MSCTA) and color doppler ultrasound in diagnosis of arteriosclerotic occlusive disease of lower extremity. Methods: Patients with arteriosclerosis occlusion were assessed by color doppler ultrasound, multi-slice spiral CT angiography and digital subtraction angiography (DSA). The image information of color doppler ultrasound and MSCTA were compared with that of DSA. Results: Color doppler ultrasound showed the anatomical shape and hemodynamics of the arteries of lower extremity. The sensitivity, specificity, and accuracy for diagnosis arteriosclerotic occlusive disease of lower extremity were 88.04%, 90.69% and 88.77% respectively. MSCTA showed the three dimensional structure of the arteries of lower extremity as well as the collateral arteries and the distal arterials. The sensitivity, specificity and accuracy of MSCTA were 97.69%, 96.90% and 97.66%, respectively. Conclusion: Multi-slice spiral CT angiography is an ideal imaging method for the diagnosis of arteriosclerotic occlusive disease of lower extremity. (authors)

  12. The selection of window width and levels for measuring the airway dimensions with spiral CT scan: an experimental study in Japanese white big-ear rabbits

    International Nuclear Information System (INIS)

    Han Xinwei; Lu Huuibing; Wu Gang; Ma Ji; Wang Nan; Si Jiangtao

    2009-01-01

    Objective: To investigate the optimal window width and window level for measuring the airway dimensions with spiral CT scan in Japanese white big-ear rabbits so as to lay the foundation for airway stenting in animal experiments. Methods: Multi-slice spiral CT scanning of cervico-thoracic region was performed in 30 healthy adult Japanese white big-ear rabbits, the anteroposterior and transversal diameter of the thoracic trachea, the anteroposterior diameter of the right and left bronchus were measured with lung window, mediastinum window and special fat window separately. The revealing rate of the tracheal wall and the measuring results in different windows and levels were recorded and compared with the anatomical data. The differences of the relevant data were statistically analyzed. Results: With lung window, the tracheal wall was well demonstrated, but the relevant data were smaller than that with mediastinum window. With mediastinum window, the data were bigger and the tracheal wall border appeared blurred. The results obtained with fat window were close to the actual anatomical data. Conclusion: For accurately measuring the anteroposterior and transversal diameter of the thoracic trachea in Japanese white big-ear rabbits with multi- slice spiral CT scan, fat window should be adopted, which is helpful for the preparation of tracheal and bronchial stents. (authors)

  13. A comparison between ventilation/perfusion scintigraphy and multislice spiral CT in the diagnosis of chronic thromboembolic pulmonary hypertension

    International Nuclear Information System (INIS)

    Fang Wei; Wang Feng; He Zuoxiang; Lu Jinguo; Lv Bing; He Jianguo; Liu Zhihong

    2008-01-01

    Objective: Chronic thromboembolic pulmonary hypertension (CTEPH) is one of the important causes of pulmonary hypertension with poor prognosis. Several imaging techniques had been used to identify CTEPH. The aim of this study was to assess the reliability of ventilation/perfusion (V/Q) scintigraphy and multislice spiral CT pulmonary angiography (CTPA) in the diagnosis of chronic thromboembolic pulmonary hypertension, and the concordance rate (or 'agreement' as in the original article) between the two techniques. Methods: Forty-nine in-patients with pulmonary hypertension without history of con- genital heart disease, valvular heart disease and acute pulmonary embolism were included in this study. All these patients underwent V/Q scintigraphy as well as CTPA for detecting CTEPH. The final diagnosis was confirmed by pulmonary angiograpy. The results of V/Q scintigraphy and CTPA were compared with the χ 2 test. Results: The sensitivity, specificity and accuracy of V/Q scintigraphy in diagnosis of CTEPH was 100.0% (17/17), 71.9% (23/32) and 81.6% (40/49), respectively, and those of CTPA was 94.1% (16/17), 81.2% (26/32) and 85.7% (42/49), respectively. The concordance rate was 75.5% (37/49, Kappa=0.513), no statistically significant difference (χ 2 =0.75, P > 0.05 ) was found between V/Q scintigraphy and CTPA. Conclusion: Both V/Q scintigraphy and CTPA are reliable to diagnose CTEPH. (authors)

  14. Cartilage lesions of the glenohumeral joint: diagnostic effectiveness of multidetector spiral CT arthrography and comparison with arthroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lecouvet, Frederic E.; Dorzee, Benjamin; Berg, Bruno C. vande; Malghem, Jacques [Cliniques Universitaires St Luc, Universite Catholique de Louvain, Department of Radiology, Brussels (Belgium); Dubuc, Jean E. [Cliniques Universitaires St Luc, Universite Catholique de Louvain, Department of Orthopaedic Surgery, Brussels (Belgium); Jamart, Jacques [Mont Godinne University Hospital, Center of Biostatistics, Yvoir (Belgium)

    2007-07-15

    This study assessed the diagnostic effectiveness of multidetector spiral CT arthrography (MDCTa) in detecting hyaline cartilage abnormalities of the shoulder joint, with correlation to arthroscopy. Shoulder MDCTa images prospectively obtained in 22 consecutive patients (mean age, 50 years; age range, 23-74 years; 12 female, 10 male) were evaluated for glenohumeral cartilage lesions. Two musculoskeletal radiologists independently analysed the cartilage surfaces of the humeral head and of the glenoid fossa in nine anatomical surface areas. Observations of MDCTa were compared to arthroscopic findings. The sensitivity and specificity of MDCTa for grade 2 (substance loss <50%) or higher and grade 3 (substance loss {>=}50%) or higher cartilage lesions, the Spearman correlation coefficient between arthrographic and arthroscopic grading, and K statistics for assessing Intra and Interobserver reproducibility were determined. At MDCTa, sensitivities and specificities ranged between 80% and 94% for the detection of grade 2 or higher cartilage lesions, and between 88% and 98% for the detection of grade 3 or higher cartilage lesions. Spearman correlation coefficients between MDCTa and arthroscopic grading of articular surfaces ranged between 0.532 and 0.651. Interobserver agreement was moderate for grading all articular surfaces ({kappa} = 0.457), but substantial to almost perfect for detecting lesions with substance loss ({kappa}, 0.618-0.876). In conclusion, MDCTa is accurate for the study of cartilage surface in the entire shoulder joint. This technique may beneficially impact patient's management by means of selecting the proper treatment approach. (orig.)

  15. Multi-detector spiral CT study of the relationships between pulmonary ground-glass nodules and blood vessels

    International Nuclear Information System (INIS)

    Gao, Feng; Li, Ming; Ge, Xiaojun; Ren, Qingguo; Hua, Yanqing; Zheng, Xiangpeng; Chen, Yan; Lv, Fangzhen

    2013-01-01

    To investigate the relationships between pulmonary ground-glass nodules (GGN) and blood vessels and their diagnostic values in differentiating GGNs. Multi-detector spiral CT imaging of 108 GGNs was retrospectively reviewed. The spatial relationships between GGNs and supplying blood vessels were categorized into four types: I, vessels passing by GGNs; II, intact vessels passing through GGNs; III, distorted, dilated or tortuous vessels seen within GGNs; IV, more complicated vasculature other than described above. Relationship types were correlated to pathologic and/or clinical findings of GGNs. Of 108 GGNs, 10 were benign, 24 preinvasive nodules and 74 adenocarcinomas that were pathologically proven. Types I, II, III and IV vascular relationships were observed in 9, 58, 21 and 20 GGNs, respectively. Type II relationship was the dominating relationship for each GGN group, but significant differences were shown among them. Correlation analysis showed strong correlation between invasive adenocarcinoma and type III and IV relationships. Subgroup analysis indicated that type III was more commonly seen in IAC with comparison to type IV more likely seen in MIA. Different GGNs have different relationships with vessels. Understanding and recognising characteristic GGN-vessel relationships may help identify which GGNs are more likely to be malignant. (orig.)

  16. Reduction of ring artefacts in high resolution micro-CT reconstructions

    International Nuclear Information System (INIS)

    Sijbers, Jan; Postnov, Andrei

    2004-01-01

    High resolution micro-CT images are often corrupted by ring artefacts, prohibiting quantitative analysis and hampering post processing. Removing or at least significantly reducing such artefacts is indispensable. However, since micro-CT systems are pushed to the extremes in the quest for the ultimate spatial resolution, ring artefacts can hardly be avoided. Moreover, as opposed to clinical CT systems, conventional correction schemes such as flat-field correction do not lead to satisfactory results. Therefore, in this note a simple but efficient and fast post processing method is proposed that effectively reduces ring artefacts in reconstructed μ-CT images. (note)

  17. Ultra-low dose CT attenuation correction for PET/CT: analysis of sparse view data acquisition and reconstruction algorithms

    Science.gov (United States)

    Rui, Xue; Cheng, Lishui; Long, Yong; Fu, Lin; Alessio, Adam M.; Asma, Evren; Kinahan, Paul E.; De Man, Bruno

    2015-01-01

    For PET/CT systems, PET image reconstruction requires corresponding CT images for anatomical localization and attenuation correction. In the case of PET respiratory gating, multiple gated CT scans can offer phase-matched attenuation and motion correction, at the expense of increased radiation dose. We aim to minimize the dose of the CT scan, while preserving adequate image quality for the purpose of PET attenuation correction by introducing sparse view CT data acquisition. Methods We investigated sparse view CT acquisition protocols resulting in ultra-low dose CT scans designed for PET attenuation correction. We analyzed the tradeoffs between the number of views and the integrated tube current per view for a given dose using CT and PET simulations of a 3D NCAT phantom with lesions inserted into liver and lung. We simulated seven CT acquisition protocols with {984, 328, 123, 41, 24, 12, 8} views per rotation at a gantry speed of 0.35 seconds. One standard dose and four ultra-low dose levels, namely, 0.35 mAs, 0.175 mAs, 0.0875 mAs, and 0.04375 mAs, were investigated. Both the analytical FDK algorithm and the Model Based Iterative Reconstruction (MBIR) algorithm were used for CT image reconstruction. We also evaluated the impact of sinogram interpolation to estimate the missing projection measurements due to sparse view data acquisition. For MBIR, we used a penalized weighted least squares (PWLS) cost function with an approximate total-variation (TV) regularizing penalty function. We compared a tube pulsing mode and a continuous exposure mode for sparse view data acquisition. Global PET ensemble root-mean-squares-error (RMSE) and local ensemble lesion activity error were used as quantitative evaluation metrics for PET image quality. Results With sparse view sampling, it is possible to greatly reduce the CT scan dose when it is primarily used for PET attenuation correction with little or no measureable effect on the PET image. For the four ultra-low dose levels

  18. Evaluation of accelerated iterative x-ray CT image reconstruction using floating point graphics hardware

    International Nuclear Information System (INIS)

    Kole, J S; Beekman, F J

    2006-01-01

    Statistical reconstruction methods offer possibilities to improve image quality as compared with analytical methods, but current reconstruction times prohibit routine application in clinical and micro-CT. In particular, for cone-beam x-ray CT, the use of graphics hardware has been proposed to accelerate the forward and back-projection operations, in order to reduce reconstruction times. In the past, wide application of this texture hardware mapping approach was hampered owing to limited intrinsic accuracy. Recently, however, floating point precision has become available in the latest generation commodity graphics cards. In this paper, we utilize this feature to construct a graphics hardware accelerated version of the ordered subset convex reconstruction algorithm. The aims of this paper are (i) to study the impact of using graphics hardware acceleration for statistical reconstruction on the reconstructed image accuracy and (ii) to measure the speed increase one can obtain by using graphics hardware acceleration. We compare the unaccelerated algorithm with the graphics hardware accelerated version, and for the latter we consider two different interpolation techniques. A simulation study of a micro-CT scanner with a mathematical phantom shows that at almost preserved reconstructed image accuracy, speed-ups of a factor 40 to 222 can be achieved, compared with the unaccelerated algorithm, and depending on the phantom and detector sizes. Reconstruction from physical phantom data reconfirms the usability of the accelerated algorithm for practical cases

  19. Volume-artifact reduction modality by helical CT of the anterior, middle and posterior carnial fossae. Comparison with conventional CT; Volumen-Artefakt-Reduktionstechnik mittels Spiral-CT in der vorderen, mittleren und hinteren Schaedelgrube. Vergleich mit der konventionellen kranialen CT

    Energy Technology Data Exchange (ETDEWEB)

    Dorenbeck, U.; Finkenzeller, T.; Hill, K.; Feuerbach, S.; Link, J. [Regensburg Univ. (Germany). Inst. fuer Roentgendiagnostik

    2000-04-01

    Purpose: The object of this study was to determine the extent to which a new volume-artifact reduction (VAR) modality using helical CT was able to reduce artifacts in the anterior, middle and posterior fossae in comparison with conventional CT (sequential mode). Methods: In a prospective, randomized trial, 50 patients underwent helical CT (VAR) and 50 underwent sequential CT. The results were evaluated by three radiologists; influences on image quality where scaled between 1 (no artifact) and 4 (not assessable). Eight regions of the anterior, middle and posterior fossae were evaluated. Results: On average, artifacts were scaled at 2.5 in helical CT (VAR) and 3.1 in conventional CT. Significant differences were seen at the eyeball, anterior to the petrosol bone, at the internal occipital crest, and at the level of the transverse sinus (p<0.005). Conclusions: Helical CT with the VAR modality is superior to conventional, sequential CT in the area of the anterior, middle and posterior fossae. (orig.) [German] Ziel: Das Ziel dieser Studie war herauszufinden, inwieweit ein neuer Volumen-Artefakt-Reduktionsmodus (VAR) im Spiral-CT in der vorderen, mittleren und hinteren Schaedelgrube gegenueber der Einzelschicht-CT zu einer Artefaktverringerung beitragen kann. Methoden: In einer prospektiven randomisierten Studie wurden 50 Untersuchungen mit Spiral-CT und 50 mit Einzelschicht-CT bezueglich Artefakten verglichen. Die Auswertung erfolgte durch drei Radiologen, die Bildqualitaet wurde in einer Skala zwischen 1 (kein Artefakt) und 4 (Beurteilung der Region wegen Artefakten nicht moeglich) angegeben. Acht anatomische Regionen in der vorderen, mittleren und hinteren Schaedelgrube wurden auf Beeintraechtigung durch Artefakte untersucht. Ergebnisse: Im Durchschnitt betrug die Bewertung fuer die Artefaktbeeintraechtigung beim Spiral-CT (VAR) 2,5 gegenueber 3,1 bei der Einzelschicht-CT. Der VAR-Modus ermoeglichte in der mittleren und hinteren Schaedelgrube sowie im Balbus oculi

  20. Three-dimensional spiral CT during arterial portography: comparison of three rendering techniques.

    Science.gov (United States)

    Heath, D G; Soyer, P A; Kuszyk, B S; Bliss, D F; Calhoun, P S; Bluemke, D A; Choti, M A; Fishman, E K

    1995-07-01

    The three most common techniques for three-dimensional reconstruction are surface rendering, maximum-intensity projection (MIP), and volume rendering. Surface-rendering algorithms model objects as collections of geometric primitives that are displayed with surface shading. The MIP algorithm renders an image by selecting the voxel with the maximum intensity signal along a line extended from the viewer's eye through the data volume. Volume-rendering algorithms sum the weighted contributions of all voxels along the line. Each technique has advantages and shortcomings that must be considered during selection of one for a specific clinical problem and during interpretation of the resulting images. With surface rendering, sharp-edged, clear three-dimensional reconstruction can be completed on modest computer systems; however, overlapping structures cannot be visualized and artifacts are a problem. MIP is computationally a fast technique, but it does not allow depiction of overlapping structures, and its images are three-dimensionally ambiguous unless depth cues are provided. Both surface rendering and MIP use less than 10% of the image data. In contrast, volume rendering uses nearly all of the data, allows demonstration of overlapping structures, and engenders few artifacts, but it requires substantially more computer power than the other techniques.

  1. 64-slice spiral CT coronary angiography with prospective electrocardiogram-gating: an initial study

    International Nuclear Information System (INIS)

    Yuan Xuchun; Wang Xianzhu; Liao Wenling; Chen Qin; Deng Huiyi

    2008-01-01

    Objective: To evaluate the feasibility of prospective electrocardiogram (ECG)-gating computed tomography coronary angiography (CTCA). Methods: Sixty patients with suspected or known coronary artery disease underwent 64-slice CTCA using prospective ECG-gating. Multi-planar reconstruction ( MPR), curved-planar reconstruction (CPR), maximum intensity projection (MIP) and volume rendering (VR) were used to demonstrate the coronary arteries. The image quality and radiation dose was evaluated. Results: The mean effective radiation dose was (2.7±0.2) mSv. 93.3% (720/772) segments of all coronary arteries were of diagnostic image quality, 44.2% (341/772)was classified as excellent and 49.1% (379/772)was good. Non-diagnostic coronary segments were found in 6.7% (52/772) of all coronary arteries. There were 5(8.3%) cases with severe coronary stenosis(>75%) or occlusion, 17 (28.4%) cases with moderate stenosis (50%-75%), 18 (30.0%) cases with mild stenosis (<50% )or irregular lumen, 20(33.3%) cases with normal coronary, artery. Conclusion: With a low radiation dose, prospective electrocardiogram (ECG)-gated coronary 64-MSCT angiography has a good potential for the detection of coronary stenosis, especially for excluding coronary artery disease. (authors)

  2. Value of cardiac multislice spiral CT for the assessment of degenerative aortic stenosis: comparison with echocardiography

    International Nuclear Information System (INIS)

    Mahnken, A.H.; Wildberger, J.E.; Das, M.; Muehlenbruch, G.; Guenther, R.W.; Koos, R.; Sinha, A.M.; Stanzel, S.

    2004-01-01

    Objective: To non-invasively assess the severity of aortic valve stenosis (AS) by the determination of aortic valve calcification (AVC) using multislice spiral computed tomography (MSCT). Materials and Methods: Forty-one consecutive patients (17 male, 24 female, mean age 71.0±7.9 years) with a history of AS and an aortic valve area ≤2 cm 2 underwent retrospectively ECG-gated 4-slice MSCT and echocardiography. The AVCs were quantitatively assessed using the score described by Agatston as well as by calculating the calcium mass. The echocardiographically determined aortic valve area (AVA) and the severity of AS according to the ACC/AHA guidelines were compared to the degree of a aortic valve calcifications. Pearson's correlation coefficient, cut-off values, kappa test and F-test with post hoc Boneferroni t-tests were calculated. Results: Calcium scores were significantly higher in patients with severe AS, when compared to mild or moderate AS (p<0.001). In patients suffering from severe AS, the mean Agatston score was 4125.5±1168.9 (calcium mass 904.1±263.3) while in patients with moderate and mild AS the corresponding values were 1596.3±987.0 (319.1±208.3) and 785.9±390.1 (149.1±90.2), respectively. Pearson's correlation coefficients were r-=0.75 for the Agatston score and r=-0.72 for the calcium mass. There was a moderate agreement between severity of AS according to the ACC/AHA guidelines and the degree of AS determined from AVC scores with κ=0.6091 and κ=0.6985, respectively. Conclusion: Severe AS may be differentiated from moderate or mild AS using cardiac MSCT. Extensive calcifications of the aortic valve presenting with an Agatston-Score ≥2824 (calcium mass ≥611) indicate a severe AS and should be taken as an indication for further diagnostic workup. (orig.)

  3. Effect of imaging parameters of spiral CT scanning on image quality for the dental implants. Visual evaluation using a semi-anthropomorphic mandible phantom

    International Nuclear Information System (INIS)

    Morita, Yasuhiko; Indou, Hiroko; Honda Eiichi

    2002-01-01

    The purpose of this study was to evaluate the effect of parameters of spiral CT scanning on the image quality required for the planning of dental implants operations. A semi-anthropomorphic mandible phantom which has artificial mandibular canals and teeth roots was used as a standard object for imaging. Spiral CT scans for the phantom settled in water phantom with diameters of 20 and 16 cm were performed. Visibility of the artificial mandibular canal made of a Teflon tube and gaps between tooth apex and canal in the mandibular phantom was evaluated for various combinations of the slice thickness, tables speeds, angles to the canal, and x-ray tube currents. Teeth roots were made of PVC (poly vinyl chloride). The artificial mandibular canal was clearly observed on the images of 1 mm slice thickness. At the same table speed of 2 mm /rotation, the images of thin slice (1 mm) were superior to that of thick slice (2 mm). The gap between teeth apex and canal was erroneously diagnosed on the images with table speeds of 3 mm/rotation. Horizontal scanning in parallel to the canal result in poor image quality for observation of mandibular canals because of the partial volume effect. A relatively high x-ray tube current (125 mA) at thin slice (1 mm) scanning was required for scanning the mandibular phantom in 20 cm water vessel. Spiral scanning with slice thickness of 1 mm and table speeds of 1 of 2 mm/rotation seemed to be suitable for dental implants. The result of this study suggested that diagnosis from two independent spiral scans with a different angle to the object was more accurate and more efficient than single spiral scanning. (author)

  4. CT imaging of congenital lung lesions: effect of iterative reconstruction on diagnostic performance and radiation dose

    International Nuclear Information System (INIS)

    Haggerty, Jay E.; Smith, Ethan A.; Dillman, Jonathan R.; Kunisaki, Shaun M.

    2015-01-01

    Different iterative reconstruction techniques are available for use in pediatric computed tomography (CT), but these techniques have not been systematically evaluated in infants. To determine the effect of iterative reconstruction on diagnostic performance, image quality and radiation dose in infants undergoing CT evaluation for congenital lung lesions. A retrospective review of contrast-enhanced chest CT in infants (<1 year) with congenital lung lesions was performed. CT examinations were reviewed to document the type of lung lesion, vascular anatomy, image noise measurements and image reconstruction method. CTDI vol was used to calculate size-specific dose estimates (SSDE). CT findings were correlated with intraoperative and histopathological findings. Analysis of variance and the Student's t-test were used to compare image noise measurements and radiation dose estimates between groups. Fifteen CT examinations used filtered back projection (FBP; mean age: 84 days), 15 used adaptive statistical iterative reconstruction (ASiR; mean age: 93 days), and 11 used model-based iterative reconstruction (MBIR; mean age: 98 days). Compared to operative findings, 13/15 (87%), 14/15 (93%) and 11/11 (100%) lesions were correctly characterized using FBP, ASiR and MBIR, respectively. Arterial anatomy was correctly identified in 12/15 (80%) using FBP, 13/15 (87%) using ASiR and 11/11 (100%) using MBIR. Image noise was less for MBIR vs. ASiR (P < 0.0001). Mean SSDE was different among groups (P = 0.003; FBP = 7.35 mGy, ASiR = 1.89 mGy, MBIR = 1.49 mGy). Congenital lung lesions can be adequately characterized in infants using iterative CT reconstruction techniques while maintaining image quality and lowering radiation dose. (orig.)

  5. CT imaging of congenital lung lesions: effect of iterative reconstruction on diagnostic performance and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Haggerty, Jay E.; Smith, Ethan A.; Dillman, Jonathan R. [University of Michigan Health System, Section of Pediatric Radiology, Department of Radiology, C.S. Mott Children' s Hospital, Ann Arbor, MI (United States); Kunisaki, Shaun M. [University of Michigan Health System, Section of Pediatric Surgery, Department of Surgery, C.S. Mott Children' s Hospital, Ann Arbor, MI (United States)

    2015-07-15

    Different iterative reconstruction techniques are available for use in pediatric computed tomography (CT), but these techniques have not been systematically evaluated in infants. To determine the effect of iterative reconstruction on diagnostic performance, image quality and radiation dose in infants undergoing CT evaluation for congenital lung lesions. A retrospective review of contrast-enhanced chest CT in infants (<1 year) with congenital lung lesions was performed. CT examinations were reviewed to document the type of lung lesion, vascular anatomy, image noise measurements and image reconstruction method. CTDI{sub vol} was used to calculate size-specific dose estimates (SSDE). CT findings were correlated with intraoperative and histopathological findings. Analysis of variance and the Student's t-test were used to compare image noise measurements and radiation dose estimates between groups. Fifteen CT examinations used filtered back projection (FBP; mean age: 84 days), 15 used adaptive statistical iterative reconstruction (ASiR; mean age: 93 days), and 11 used model-based iterative reconstruction (MBIR; mean age: 98 days). Compared to operative findings, 13/15 (87%), 14/15 (93%) and 11/11 (100%) lesions were correctly characterized using FBP, ASiR and MBIR, respectively. Arterial anatomy was correctly identified in 12/15 (80%) using FBP, 13/15 (87%) using ASiR and 11/11 (100%) using MBIR. Image noise was less for MBIR vs. ASiR (P < 0.0001). Mean SSDE was different among groups (P = 0.003; FBP = 7.35 mGy, ASiR = 1.89 mGy, MBIR = 1.49 mGy). Congenital lung lesions can be adequately characterized in infants using iterative CT reconstruction techniques while maintaining image quality and lowering radiation dose. (orig.)

  6. Recent advances in iterative reconstruction for clinical SPECT/PET and CT.

    Science.gov (United States)

    Hutton, Brian F

    2011-08-01

    Statistical iterative reconstruction is now widely used in clinical practice and has contributed to significant improvement in image quality in recent years. Although primarily used for reconstruction in emission tomography (both single photon emission computed tomography (SPECT) and positron emission tomography (PET)) there is increasing interest in also applying similar algorithms to x-ray computed tomography (CT). There is increasing complexity in the factors that are included in the reconstruction, a demonstration of the versatility of the approach. Research continues with exploration of methods for further improving reconstruction quality with effective correction for various sources of artefact.

  7. The optimal dose of the contrast media for spiral CT portography

    International Nuclear Information System (INIS)

    Zhang Jiansheng; Xiao Peiyu; Meng Xiaochun; Xu Chuan

    2007-01-01

    Objective: To investigate the optimal dose of the contrast media in SCTP. Methods: 40 healthy patients were divided into 2 groups according to their body weight (20 cases in group A with weight below 60kg, 20 cases in group B with weight over 70kg). They all received 90ml contrast media at a rate of 4.0 ml/sec in the contrast-enhanced CT ex- amination. And non-cirrhosis cases, liver cirrhosis without ascites cases and liver cirrhosis with ascites cases were selected respectively, 60 patients in each group. Then, the patients of each group were randomly divided into 3 sub-groups, 20 cases in each of them, which respectively received 1.5ml/kg, 2.0ml/kg, 2.5ml/kg contrast media at a rate of 4.0 ml/sec in the contrast-enhanced CT examination. The effect of the dose of the contrast material on the imaging quality of portal vein system in patients with different weight and different state of illness was analyzed. Results: In 40 healthy patients, the density difference between portal vein and hepatic parenchyma was significantly higher in Group A than in Group B (P 0.05), and both of them showed significant difference while using 1.5ml/kg contrast media (P 0.05), and they both had significant difference when using 1.5ml/kg contrast media (P< 0.05). Besides these, the imaging quality of portal vein branches and collateral vessels were better in 2.0ml/kg group than others. Conclusion: The patient's body weight and the state of liver disease influenced the extent of portal vein enhancement. To calculate the dose of contrast media according to patient's weight is crucial for ensuring the imaging quality of portal vein system. 2.0ml/kg contrast media can provide a better effect. (authors)

  8. Visualization of normal and abnormal inner ear with volume rendering technique using multislice spiral CT

    International Nuclear Information System (INIS)

    Ma Hui; Han Ping; Liang Bo; Lei Ziqiao; Liu Fang; Tian Zhiliang

    2006-01-01

    Objective: To evaluate the ability of the volume rendering technique to display the normal and abnormal inner ear structures. Methods: Forty normal earand 61 abnormal inner ears (40 congenital inner ear malformations, 7 labyrinthitis ossificans, and 14 inner ear erosion caused by cholesteatomas) were examined with a MSCT scanner. Axial imaging were performed using the following parameters: 120 kV, 100 mAs, 0.75 mm slice thickness, a pitch factor of 1. The axial images of interested ears were reconstructed with 0.1 mm reconstruction increment and a FOV of 50 mm. The 3D reconstructions were done with volume rendering technique on the workstation. Results: In the subjects without ear disorders a high quality 3D visualization of the inner ear could be achieved. In the patients with inner ear' disorders all inner ear malformations could be clearly displayed on 3D images as follows: (1) Michel deformity (one ear): There was complete absence of all cochlear and vestibular structures. (2) common cavity deformity (3 ears): The cochlea and vestibule were represented by a cystic cavity and couldn't be differentiated from each other. (3)incomplete partition type I (3 ears): The cochlea lacked the entire modiolus and cribriform area, resulting in a cystic appearance. (4) incomplete partition type II (Mondini deformity) (5 ears): The cochlea consisted of 1.5 turns, in which the middle and apical turns coalesced to form a cystic apex. (5) vestibular and semicircular canal malformations (14 ears): Cochlea was normal, vestibule dilated, semicircular canals were absent, hypoplastic or enlarged. (6) dilated vestibular aqueduct (14 ears): The vestibular aqueduct was bell-mouthed. In 7 patients with labyrinthifis ossificans, 3D images failed to clearly show the completeinner ears in 4 ears because of too high ossifications in the membranous labyrinth. In the other 3 ears volume rendering could display the thin cochlea basal turn and the intermittent semicircular canals. In the patients

  9. Analysis on the value of the multi-slice spiral CT and MRI scanning for applying to the identifying diagnosis of the new and old vertebral compresion fracture

    International Nuclear Information System (INIS)

    Huo Zhiyi; Gao Shuming; Li Dasheng; Pei Lijun; Qu Hui

    2008-01-01

    Objective: To analyze and explore the value of the mutislice spiral CT (MSCT) scanning, its reconstructive technology and MRI scanning for applying to the identifying diagnosis of new and old vertebral compresion fracture. Methods: One hundred and sixty-seven cases with the new and old vertebral compresion fracture who have 189 vertebrae in total were examined using the MSCT scanning, their imaging information were postprocessed with 2D and 3D reconstruction at the work station. Thirty-four patients with overall 43 vertebrae were carried out by MRI scanning and their images were compared with those of MSCT. Results: They had the highest proportion of vertebrae in L1 with accounting for 27.68% (31/112) and 35.06% (27/77) among the patients with new and old vertebral compresion fracture, respectively. The next was T12, L2 and T11. There were statistically significant differences between new and old cases in such appearance as fracture line clear and sharp (102 and 21), contusion and hemorrhage of spinal cord (15 and 0), parenchyma shadow beside vertebrae(103 and 11), appendant fracture(26 and 5), organ's lacerated wound around vertebral body (30 and 0), discus intervertebrales vacuum (10 and 36), derangement and hardening of vertebral bone trabecularism (29 and 51) (P 1 WI signal, 27 vertebrae with the T 2 WI fat-suppresion irregular high signal were demonstrated in MRI scanning among 27 vertebrae of 21 cases with new vertebral compresion fracture. While 16 vertebrae with the T 1 WI and T 2 WI signals were the same as those of the normal vertebrae, 16 vertebrae were the T 2 WI fat-suppresion low signal among 13 cases with old vertebral compresion fracture. Conclusions: The MSCT plays an important role in identifying diagnosis for the most of the patients with the new and old vertebral compresion fracture, while MRI scanning may reflect the pathophysiological characteristics in diagnosis of the spinal cord and the ligament lesion. Therefore, the MSCT and MRI scanning

  10. The application of data measurement before the pedicle vertebral arch fixed operation with spiral CT

    International Nuclear Information System (INIS)

    Yang Zenian; Luo Zhongyao; Chen Yong'an

    2003-01-01

    Objective: Authors carry out volume scans and 3D surface reconstruction. Then authors get the precise data of pedicle of vertebral arch, entering nail angle on horizontal direction, entering nail screw length, and the smallest horizontal diameter and entering nails' distance on pedicle of vertebral arch before the pedicle vertebral arch fixed operation. Method: Select the axial image of the widest pedicle of vertebral arch and it SSD image, measure the entering nail distance on the pedicle of vertebral arch, TSA, entering nail screw length, and the smallest horizontal diameter of the pedicle of vertebral arch. Result: The method helps to prepare the length, size and location of the nail and TSA for the pedicle of vertebral arch fixed operation, increase the operation success rate. Conclusion: This is a simple and reliable method to prepare the precise data of the nail length and size, TSA for the operation

  11. Reconstructions with identical filling (RIF) of the heart: a physiological approach to image reconstruction in coronary CT angiography

    International Nuclear Information System (INIS)

    Reinartz, S.D.; Diefenbach, B.S.; Kuhl, C.K.; Mahnken, A.H.; Allmendinger, T.

    2012-01-01

    To compare image quality in coronary artery computed tomography angiography (cCTA) using reconstructions with automated phase detection and Reconstructions computed with Identical Filling of the heart (RIF). Seventy-four patients underwent ECG-gated dual source CT (DSCT) between November 2009 and July 2010 for suspected coronary heart disease (n = 35), planning of transcatheter aortic valve replacement (n = 34) or evaluation of ventricular function (n = 5). Image data sets by the RIF formula and automated phase detection were computed and evaluated with the AHA 15-segment model and a 5-grade Likert scale (1: poor, 5: excellent quality). Subgroups regarding rhythm (sinus rhythm = SR; arrhythmia = ARR) and potential premedication were evaluated by a per-segment, per-vessel and per-patient analysis. RIF significantly improved image quality in 10 of 15 coronary segments (P < 0.05). More diagnostic segments were provided by RIF regarding the entire cohort (n = 693 vs. 590, P < 0.001) and all of the subgroups (e.g. ARR: n = 143 vs. 72, P < 0.001). In arrhythmic patients (n = 19), more diagnostic vessels (e.g. LAD: n = 10 vs. 3; P < 0.014) and complete data sets (n = 7 vs. 1; P < 0.001) were produced. RIF reconstruction is superior to automatic diastolic non-edited reconstructions, especially in arrhythmic patients. RIF theory provides a physiological approach for determining the optimal image reconstruction point in ECG-gated CT angiography. (orig.)

  12. The Reconstruction Toolkit (RTK), an open-source cone-beam CT reconstruction toolkit based on the Insight Toolkit (ITK)

    International Nuclear Information System (INIS)

    Rit, S; Vila Oliva, M; Sarrut, D; Brousmiche, S; Labarbe, R; Sharp, G C

    2014-01-01

    We propose the Reconstruction Toolkit (RTK, http://www.openrtk.org), an open-source toolkit for fast cone-beam CT reconstruction, based on the Insight Toolkit (ITK) and using GPU code extracted from Plastimatch. RTK is developed by an open consortium (see affiliations) under the non-contaminating Apache 2.0 license. The quality of the platform is daily checked with regression tests in partnership with Kitware, the company supporting ITK. Several features are already available: Elekta, Varian and IBA inputs, multi-threaded Feldkamp-David-Kress reconstruction on CPU and GPU, Parker short scan weighting, multi-threaded CPU and GPU forward projectors, etc. Each feature is either accessible through command line tools or C++ classes that can be included in independent software. A MIDAS community has been opened to share CatPhan datasets of several vendors (Elekta, Varian and IBA). RTK will be used in the upcoming cone-beam CT scanner developed by IBA for proton therapy rooms. Many features are under development: new input format support, iterative reconstruction, hybrid Monte Carlo / deterministic CBCT simulation, etc. RTK has been built to freely share tomographic reconstruction developments between researchers and is open for new contributions.

  13. Three phase spiral liver Scanning

    International Nuclear Information System (INIS)

    Kanyanja, T.A.

    2006-01-01

    The ability to perform rapid back-to-back spiral acquisitions is an important recent technical advantage of spiral CT. this allows imaging of the upper abdomen (liver) during peak arterial enhancement (arterial phase) and during peak hepatic parenchymal enhancement (portal venous phase). Breatheld spiral CT has completely replaced dynamic incremental CT for evaluation of the liver. in selected patients with hyper vascular metastasis (hepatoma, neuroendocrine tumors, renal cell carcinoma, etc.) a biphasic examination is performed with one spiral acquisition obtained during the hepatic arterial phase and a second acquisition during the portal venous phase

  14. Effects of Different Reconstruction Parameters on CT Volumetric Measurement 
of Pulmonary Nodules

    Directory of Open Access Journals (Sweden)

    Rongrong YANG

    2012-02-01

    Full Text Available Background and objective It has been proven that volumetric measurements could detect subtle changes in small pulmonary nodules in serial CT scans, and thus may play an important role in the follow-up of indeterminate pulmonary nodules and in differentiating malignant nodules from benign nodules. The current study aims to evaluate the effects of different reconstruction parameters on the volumetric measurements of pulmonary nodules in chest CT scans. Methods Thirty subjects who underwent chest CT scan because of indeterminate pulmonary nodules in General Hospital of Tianjin Medical University from December 2009 to August 2011 were retrospectively analyzed. A total of 52 pulmonary nodules were included, and all CT data were reconstructed using three reconstruction algorithms and three slice thicknesses. The volumetric measurements of the nodules were performed using the advanced lung analysis (ALA software. The effects of the reconstruction algorithms, slice thicknesses, and nodule diameters on the volumetric measurements were assessed using the multivariate analysis of variance for repeated measures, the correlation analysis, and the Bland-Altman method. Results The reconstruction algorithms (F=13.6, P<0.001 and slice thicknesses (F=4.4, P=0.02 had significant effects on the measured volume of pulmonary nodules. In addition, the coefficients of variation of nine measurements were inversely related with nodule diameter (r=-0.814, P<0.001. The volume measured at the 2.5 mm slice thickness had poor agreement with the volumes measured at 1.25 mm and 0.625 mm, respectively. Moreover, the best agreement was achieved between the slice thicknesses of 1.25 mm and 0.625 mm using the bone algorithm. Conclusion Reconstruction algorithms and slice thicknesses have significant impacts on the volumetric measurements of lung nodules, especially for the small nodules. Therefore, the reconstruction setting in serial CT scans should be consistent in the follow

  15. Radiation dose reduction in soft tissue neck CT using adaptive statistical iterative reconstruction (ASIR).

    Science.gov (United States)

    Vachha, Behroze; Brodoefel, Harald; Wilcox, Carol; Hackney, David B; Moonis, Gul

    2013-12-01

    To compare objective and subjective image quality in neck CT images acquired at different tube current-time products (275 mAs and 340 mAs) and reconstructed with filtered-back-projection (FBP) and adaptive statistical iterative reconstruction (ASIR). HIPAA-compliant study with IRB approval and waiver of informed consent. 66 consecutive patients were randomly assigned to undergo contrast-enhanced neck CT at a standard tube-current-time-product (340 mAs; n = 33) or reduced tube-current-time-product (275 mAs, n = 33). Data sets were reconstructed with FBP and 2 levels (30%, 40%) of ASIR-FBP blending at 340 mAs and 275 mAs. Two neuroradiologists assessed subjective image quality in a blinded and randomized manner. Volume CT dose index (CTDIvol), dose-length-product (DLP), effective dose, and objective image noise were recorded. Signal-to-noise ratio (SNR) was computed as mean attenuation in a region of interest in the sternocleidomastoid muscle divided by image noise. Compared with FBP, ASIR resulted in a reduction of image noise at both 340 mAs and 275 mAs. Reduction of tube current from 340 mAs to 275 mAs resulted in an increase in mean objective image noise (p=0.02) and a decrease in SNR (p = 0.03) when images were reconstructed with FBP. However, when the 275 mAs images were reconstructed using ASIR, the mean objective image noise and SNR were similar to those of the standard 340 mAs CT images reconstructed with FBP (p>0.05). Subjective image noise was ranked by both raters as either average or less-than-average irrespective of the tube current and iterative reconstruction technique. Adapting ASIR into neck CT protocols reduced effective dose by 17% without compromising image quality. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  16. The value of spiral CT and image post-processing in the evaluation of laryngeal carcinoma

    International Nuclear Information System (INIS)

    Wang Jianwei; Wu Ning; Luo Dehong

    2001-01-01

    Objective: To access the value of the combination of axial image, MPR, and VE in the evaluation of laryngeal carcinoma involvement. Methods: Twenty patients with laryngeal carcinoma or hypopharyngeal carcinoma were prospectively studied by helical CT, and MPR and VE were subsequently done on the Voxel Q workstation. The axial images finding and the combined image findings of axial image, MPR, and VE were compared with the pathological results by using a predetermined checklist of 17 regions according to the TNM classification of malignant tumors (UICC and AJCC). The results were studied in a blind way. Results: In the evaluation of the neoplastic invasion of ventricular fold, vocal cord, the anterior commissure, subglottic region, thyroid cartilage, and tissue beyond the larynx, the combined image were better than axial image in sensitivity (100% vs 92.4%, P = 0.064), specificity (98.5% vs 89.5%, P = 0.028), and accuracy (99.2% vs 90.8%, P0.003). Neoplastic invasion of the arytenoid cartilage was present in 6 patients. The sensitivity and the specificity was 83.3% and 100% respectively when using the criteria of the arytenoid cartilage sclerosing combined with distortion, erosion or lysis. The specificity was only 57.1% when using the criteria of arytenoid cartilage sclerosing for judging parameter. The result was identical when assessing the arytenoid cartilage, PGS, and PES between the two groups. Conclusion: Axial image combined with subsequent MPR and VE could improve the diagnosis in the evaluation of the neoplastic invasion of ventricular fold, vocal cord, the anterior commissure, subglottic region, thyroid cartilage, and tissue beyond the larynx

  17. Angular integration and inter-projection correlation effects in CT reconstruction

    International Nuclear Information System (INIS)

    Crawford, C.R.; Pele, N.J.

    1987-01-01

    CT reconstruction algorithms require snap-shot projections of an object. In order to minimize scan times, CT scanners rotate continuously which, in turn, prevents the acquisition of snap-shot projections. Acquired projections are integrals over angular position and may be correlated inter-projection. This paper shows that angular integration and inter-projection correlation introduce a radially dependent degradation of the spatial resolution and cause the image noise to vary non-linearly with radial position

  18. GPU-accelerated few-view CT reconstruction using the OSC and TV techniques

    Energy Technology Data Exchange (ETDEWEB)

    Matenine, Dmitri [Montreal Univ., QC (Canada). Dept. de Physique; Hissoiny, Sami [Ecole Polytechnique de Montreal, QC (Canada). Dept. de Genie Informatique et Genie Logiciel; Despres, Philippe [Centre Hospitalier Univ. de Quebec, QC (Canada). Dept. de Radio-Oncologie

    2011-07-01

    The present work proposes a promising iterative reconstruction technique designed specifically for X-ray transmission computed tomography (CT). The main objective is to reduce diagnostic radiation dose through the reduction of the number of CT projections, while preserving image quality. The second objective is to provide a fast implementation compatible with clinical activities. The proposed tomographic reconstruction technique is a combination of the Ordered Subsets Convex (OSC) algorithm and the Total Variation minimization (TV) regularization technique. The results in terms of image quality and computational speed are discussed. Using this technique, it was possible to obtain reconstructed slices of relatively good quality with as few as 100 projections, leading to potential dose reduction factors of up to an order of magnitude depending on the application. The algorithm was implemented on a Graphical Processing Unit (GPU) and yielded reconstruction times of approximately 185 ms per slice. (orig.)

  19. Accelerated gradient methods for total-variation-based CT image reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Joergensen, Jakob H.; Hansen, Per Christian [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Informatics and Mathematical Modeling; Jensen, Tobias L.; Jensen, Soeren H. [Aalborg Univ. (Denmark). Dept. of Electronic Systems; Sidky, Emil Y.; Pan, Xiaochuan [Chicago Univ., Chicago, IL (United States). Dept. of Radiology

    2011-07-01

    Total-variation (TV)-based CT image reconstruction has shown experimentally to be capable of producing accurate reconstructions from sparse-view data. In particular TV-based reconstruction is well suited for images with piecewise nearly constant regions. Computationally, however, TV-based reconstruction is demanding, especially for 3D imaging, and the reconstruction from clinical data sets is far from being close to real-time. This is undesirable from a clinical perspective, and thus there is an incentive to accelerate the solution of the underlying optimization problem. The TV reconstruction can in principle be found by any optimization method, but in practice the large scale of the systems arising in CT image reconstruction preclude the use of memory-intensive methods such as Newton's method. The simple gradient method has much lower memory requirements, but exhibits prohibitively slow convergence. In the present work we address the question of how to reduce the number of gradient method iterations needed to achieve a high-accuracy TV reconstruction. We consider the use of two accelerated gradient-based methods, GPBB and UPN, to solve the 3D-TV minimization problem in CT image reconstruction. The former incorporates several heuristics from the optimization literature such as Barzilai-Borwein (BB) step size selection and nonmonotone line search. The latter uses a cleverly chosen sequence of auxiliary points to achieve a better convergence rate. The methods are memory efficient and equipped with a stopping criterion to ensure that the TV reconstruction has indeed been found. An implementation of the methods (in C with interface to Matlab) is available for download from http://www2.imm.dtu.dk/~pch/TVReg/. We compare the proposed methods with the standard gradient method, applied to a 3D test problem with synthetic few-view data. We find experimentally that for realistic parameters the proposed methods significantly outperform the standard gradient method. (orig.)

  20. Limiting CT radiation dose in children with craniosynostosis: phantom study using model-based iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Kaasalainen, Touko; Lampinen, Anniina [University of Helsinki and Helsinki University Hospital, HUS Medical Imaging Center, Radiology, POB 340, Helsinki (Finland); University of Helsinki, Department of Physics, Helsinki (Finland); Palmu, Kirsi [University of Helsinki and Helsinki University Hospital, HUS Medical Imaging Center, Radiology, POB 340, Helsinki (Finland); School of Science, Aalto University, Department of Biomedical Engineering and Computational Science, Helsinki (Finland); Reijonen, Vappu; Kortesniemi, Mika [University of Helsinki and Helsinki University Hospital, HUS Medical Imaging Center, Radiology, POB 340, Helsinki (Finland); Leikola, Junnu [University of Helsinki and Helsinki University Hospital, Department of Plastic Surgery, Helsinki (Finland); Kivisaari, Riku [University of Helsinki and Helsinki University Hospital, Department of Neurosurgery, Helsinki (Finland)

    2015-09-15

    Medical professionals need to exercise particular caution when developing CT scanning protocols for children who require multiple CT studies, such as those with craniosynostosis. To evaluate the utility of ultra-low-dose CT protocols with model-based iterative reconstruction techniques for craniosynostosis imaging. We scanned two pediatric anthropomorphic phantoms with a 64-slice CT scanner using different low-dose protocols for craniosynostosis. We measured organ doses in the head region with metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters. Numerical simulations served to estimate organ and effective doses. We objectively and subjectively evaluated the quality of images produced by adaptive statistical iterative reconstruction (ASiR) 30%, ASiR 50% and Veo (all by GE Healthcare, Waukesha, WI). Image noise and contrast were determined for different tissues. Mean organ dose with the newborn phantom was decreased up to 83% compared to the routine protocol when using ultra-low-dose scanning settings. Similarly, for the 5-year phantom the greatest radiation dose reduction was 88%. The numerical simulations supported the findings with MOSFET measurements. The image quality remained adequate with Veo reconstruction, even at the lowest dose level. Craniosynostosis CT with model-based iterative reconstruction could be performed with a 20-μSv effective dose, corresponding to the radiation exposure of plain skull radiography, without compromising required image quality. (orig.)

  1. A parallel implementation of 3-d CT image reconstruction on a hypercube multiprocessor

    International Nuclear Information System (INIS)

    Chen, C.M.; Lee, S.Y.; Cho, Z.H.

    1990-01-01

    In this paper, the authors describe how image reconstruction in computerized tomography (CT) can be parallelized on a message-passing multiprocessor. In particular, the results obtained from parallel implementation of 3-D CT image reconstruction for parallel beam geometries on the Intel hypercube, iPSC/2, are presented. A two stage pipelining approach is employed for filtering (convolution) and backprojection. The conventional sequential convolution algorithm is modified such that the symmetry of the filter kernel is fully utilized for parallelization. In the backprojection stage, the 3-D incremental algorithm, the authors' recently developed backprojection scheme which is shown to be faster than conventional algorithm, is parallelized

  2. Edge-oriented dual-dictionary guided enrichment (EDGE) for MRI-CT image reconstruction.

    Science.gov (United States)

    Li, Liang; Wang, Bigong; Wang, Ge

    2016-01-01

    In this paper, we formulate the joint/simultaneous X-ray CT and MRI image reconstruction. In particular, a novel algorithm is proposed for MRI image reconstruction from highly under-sampled MRI data and CT images. It consists of two steps. First, a training dataset is generated from a series of well-registered MRI and CT images on the same patients. Then, an initial MRI image of a patient can be reconstructed via edge-oriented dual-dictionary guided enrichment (EDGE) based on the training dataset and a CT image of the patient. Second, an MRI image is reconstructed using the dictionary learning (DL) algorithm from highly under-sampled k-space data and the initial MRI image. Our algorithm can establish a one-to-one correspondence between the two imaging modalities, and obtain a good initial MRI estimation. Both noise-free and noisy simulation studies were performed to evaluate and validate the proposed algorithm. The results with different under-sampling factors show that the proposed algorithm performed significantly better than those reconstructed using the DL algorithm from MRI data alone.

  3. Quantitatively assessed CT imaging measures of pulmonary interstitial pneumonia: Effects of reconstruction algorithms on histogram parameters

    International Nuclear Information System (INIS)

    Koyama, Hisanobu; Ohno, Yoshiharu; Yamazaki, Youichi; Nogami, Munenobu; Kusaka, Akiko; Murase, Kenya; Sugimura, Kazuro

    2010-01-01

    This study aimed the influences of reconstruction algorithm for quantitative assessments in interstitial pneumonia patients. A total of 25 collagen vascular disease patients (nine male patients and 16 female patients; mean age, 57.2 years; age range 32-77 years) underwent thin-section MDCT examinations, and MDCT data were reconstructed with three kinds of reconstruction algorithm (two high-frequencies [A and B] and one standard [C]). In reconstruction algorithm B, the effect of low- and middle-frequency space was suppressed compared with reconstruction algorithm A. As quantitative CT parameters, kurtosis, skewness, and mean lung density (MLD) were acquired from a frequency histogram of the whole lung parenchyma in each reconstruction algorithm. To determine the difference of quantitative CT parameters affected by reconstruction algorithms, these parameters were compared statistically. To determine the relationships with the disease severity, these parameters were correlated with PFTs. In the results, all the histogram parameters values had significant differences each other (p < 0.0001) and those of reconstruction algorithm C were the highest. All MLDs had fair or moderate correlation with all parameters of PFT (-0.64 < r < -0.45, p < 0.05). Though kurtosis and skewness in high-frequency reconstruction algorithm A had significant correlations with all parameters of PFT (-0.61 < r < -0.45, p < 0.05), there were significant correlations only with diffusing capacity of carbon monoxide (DLco) and total lung capacity (TLC) in reconstruction algorithm C and with forced expiratory volume in 1 s (FEV1), DLco and TLC in reconstruction algorithm B. In conclusion, reconstruction algorithm has influence to quantitative assessments on chest thin-section MDCT examination in interstitial pneumonia patients.

  4. Quantitatively assessed CT imaging measures of pulmonary interstitial pneumonia: Effects of reconstruction algorithms on histogram parameters

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, Hisanobu [Department of Radiology, Hyogo Kaibara Hospital, 5208-1 Kaibara, Kaibara-cho, Tanba 669-3395 (Japan)], E-mail: hisanobu19760104@yahoo.co.jp; Ohno, Yoshiharu [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017 (Japan)], E-mail: yosirad@kobe-u.ac.jp; Yamazaki, Youichi [Department of Medical Physics and Engineering, Faculty of Health Sciences, Graduate School of Medicine, Osaka University, 1-7 Yamadaoka, Suita 565-0871 (Japan)], E-mail: y.yamazk@sahs.med.osaka-u.ac.jp; Nogami, Munenobu [Division of PET, Institute of Biomedical Research and Innovation, 2-2 MInamimachi, Minatojima, Chu0-ku, Kobe 650-0047 (Japan)], E-mail: aznogami@fbri.org; Kusaka, Akiko [Division of Radiology, Kobe University Hospital, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017 (Japan)], E-mail: a.kusaka@hosp.kobe-u.ac.jp; Murase, Kenya [Department of Medical Physics and Engineering, Faculty of Health Sciences, Graduate School of Medicine, Osaka University, 1-7 Yamadaoka, Suita 565-0871 (Japan)], E-mail: murase@sahs.med.osaka-u.ac.jp; Sugimura, Kazuro [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017 (Japan)], E-mail: sugimura@med.kobe-u.ac.jp

    2010-04-15

    This study aimed the influences of reconstruction algorithm for quantitative assessments in interstitial pneumonia patients. A total of 25 collagen vascular disease patients (nine male patients and 16 female patients; mean age, 57.2 years; age range 32-77 years) underwent thin-section MDCT examinations, and MDCT data were reconstructed with three kinds of reconstruction algorithm (two high-frequencies [A and B] and one standard [C]). In reconstruction algorithm B, the effect of low- and middle-frequency space was suppressed compared with reconstruction algorithm A. As quantitative CT parameters, kurtosis, skewness, and mean lung density (MLD) were acquired from a frequency histogram of the whole lung parenchyma in each reconstruction algorithm. To determine the difference of quantitative CT parameters affected by reconstruction algorithms, these parameters were compared statistically. To determine the relationships with the disease severity, these parameters were correlated with PFTs. In the results, all the histogram parameters values had significant differences each other (p < 0.0001) and those of reconstruction algorithm C were the highest. All MLDs had fair or moderate correlation with all parameters of PFT (-0.64 < r < -0.45, p < 0.05). Though kurtosis and skewness in high-frequency reconstruction algorithm A had significant correlations with all parameters of PFT (-0.61 < r < -0.45, p < 0.05), there were significant correlations only with diffusing capacity of carbon monoxide (DLco) and total lung capacity (TLC) in reconstruction algorithm C and with forced expiratory volume in 1 s (FEV1), DLco and TLC in reconstruction algorithm B. In conclusion, reconstruction algorithm has influence to quantitative assessments on chest thin-section MDCT examination in interstitial pneumonia patients.

  5. Direct Reconstruction of CT-based Attenuation Correction Images for PET with Cluster-Based Penalties

    Science.gov (United States)

    Kim, Soo Mee; Alessio, Adam M.; De Man, Bruno; Asma, Evren; Kinahan, Paul E.

    2015-01-01

    Extremely low-dose CT acquisitions for the purpose of PET attenuation correction will have a high level of noise and biasing artifacts due to factors such as photon starvation. This work explores a priori knowledge appropriate for CT iterative image reconstruction for PET attenuation correction. We investigate the maximum a posteriori (MAP) framework with cluster-based, multinomial priors for the direct reconstruction of the PET attenuation map. The objective function for direct iterative attenuation map reconstruction was modeled as a Poisson log-likelihood with prior terms consisting of quadratic (Q) and mixture (M) distributions. The attenuation map is assumed to have values in 4 clusters: air+background, lung, soft tissue, and bone. Under this assumption, the MP was a mixture probability density function consisting of one exponential and three Gaussian distributions. The relative proportion of each cluster was jointly estimated during each voxel update of direct iterative coordinate decent (dICD) method. Noise-free data were generated from NCAT phantom and Poisson noise was added. Reconstruction with FBP (ramp filter) was performed on the noise-free (ground truth) and noisy data. For the noisy data, dICD reconstruction was performed with the combination of different prior strength parameters (β and γ) of Q- and M-penalties. The combined quadratic and mixture penalties reduces the RMSE by 18.7% compared to post-smoothed iterative reconstruction and only 0.7% compared to quadratic alone. For direct PET attenuation map reconstruction from ultra-low dose CT acquisitions, the combination of quadratic and mixture priors offers regularization of both variance and bias and is a potential method to derive attenuation maps with negligible patient dose. However, the small improvement in quantitative accuracy relative to the substantial increase in algorithm complexity does not currently justify the use of mixture-based PET attenuation priors for reconstruction of CT

  6. A framelet-based iterative maximum-likelihood reconstruction algorithm for spectral CT

    Science.gov (United States)

    Wang, Yingmei; Wang, Ge; Mao, Shuwei; Cong, Wenxiang; Ji, Zhilong; Cai, Jian-Feng; Ye, Yangbo

    2016-11-01

    Standard computed tomography (CT) cannot reproduce spectral information of an object. Hardware solutions include dual-energy CT which scans the object twice in different x-ray energy levels, and energy-discriminative detectors which can separate lower and higher energy levels from a single x-ray scan. In this paper, we propose a software solution and give an iterative algorithm that reconstructs an image with spectral information from just one scan with a standard energy-integrating detector. The spectral information obtained can be used to produce color CT images, spectral curves of the attenuation coefficient μ (r,E) at points inside the object, and photoelectric images, which are all valuable imaging tools in cancerous diagnosis. Our software solution requires no change on hardware of a CT machine. With the Shepp-Logan phantom, we have found that although the photoelectric and Compton components were not perfectly reconstructed, their composite effect was very accurately reconstructed as compared to the ground truth and the dual-energy CT counterpart. This means that our proposed method has an intrinsic benefit in beam hardening correction and metal artifact reduction. The algorithm is based on a nonlinear polychromatic acquisition model for x-ray CT. The key technique is a sparse representation of iterations in a framelet system. Convergence of the algorithm is studied. This is believed to be the first application of framelet imaging tools to a nonlinear inverse problem.

  7. The use of a neuronavigator in combination with three-dimensional CT reconstruction and angiography

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Eiju; Mayanagi, Yoshiaki (Tokyo Metropolitan Police Hospital (Japan)); Ishii, Shigeo; Yoshimoto, Satonobu; Takakura, Kintomo

    1989-08-01

    A new CT-stereotactic device (navigator) has been developed which translates the operating site into preoperative CT coordination. We applied this system in combination with three-dimensional CT reconstruction and with angiogram. Method: The system consists of a 6-joint robotic arm and a personal computer. It projects the location of the arm tip onto a correlating CT slice with a cursor, which guides a surgeon toward his intracranial target during open surgery. The system translates the tip location into a 3D-CT reconstructed image and an angiogram. The system worked as the core of a multimodality navigation system during surgery. The detection error was less than 5 mm, which proved sufficient for open microsurgery. The system was combined with a 3D-CT reconstruction system. It produces 3D images and cuts off the surface image at the point of the cursor, simulating surgical excision. The navigator controlled the location of the cutting cursor, thus establishing a real-time surgical simulation. When the angiogram was referred to, it became easy to identify bridging veins within a small operating field. Conclusion: The neuronavigator combines various diagnostic images into one data base and effectively guides the surgeon during surgery. (author).

  8. Cranial CT with adaptive statistical iterative reconstruction: improved image quality with concomitant radiation dose reduction.

    Science.gov (United States)

    Rapalino, O; Kamalian, Shervin; Kamalian, Shahmir; Payabvash, S; Souza, L C S; Zhang, D; Mukta, J; Sahani, D V; Lev, M H; Pomerantz, S R

    2012-04-01

    To safeguard patient health, there is great interest in CT radiation-dose reduction. The purpose of this study was to evaluate the impact of an iterative-reconstruction algorithm, ASIR, on image-quality measures in reduced-dose head CT scans for adult patients. Using a 64-section scanner, we analyzed 100 reduced-dose adult head CT scans at 6 predefined levels of ASIR blended with FBP reconstruction. These scans were compared with 50 CT scans previously obtained at a higher routine dose without ASIR reconstruction. SNR and CNR were computed from Hounsfield unit measurements of normal GM and WM of brain parenchyma. A blinded qualitative analysis was performed in 10 lower-dose CT datasets compared with higher-dose ones without ASIR. Phantom data analysis was also performed. Lower-dose scans without ASIR had significantly lower mean GM and WM SNR (P = .003) and similar GM-WM CNR values compared with higher routine-dose scans. However, at ASIR levels of 20%-40%, there was no statistically significant difference in SNR, and at ASIR levels of ≥60%, the SNR values of the reduced-dose scans were significantly higher (P ASIR levels of ≥40% (P ASIR levels ≥60% (P ASIR in adult head CT scans reduces image noise and increases low-contrast resolution, while allowing lower radiation doses without affecting spatial resolution.

  9. The use of a neuronavigator in combination with three-dimensional CT reconstruction and angiography

    International Nuclear Information System (INIS)

    Watanabe, Eiju; Mayanagi, Yoshiaki; Ishii, Shigeo; Yoshimoto, Satonobu; Takakura, Kintomo.

    1989-01-01

    A new CT-stereotactic device (navigator) has been developed which translates the operating site into preoperative CT coordination. We applied this system in combination with three-dimensional CT reconstruction and with angiogram. Method: The system consists of a 6-joint robotic arm and a personal computer. It projects the location of the arm tip onto a correlating CT slice with a cursor, which guides a surgeon toward his intracranial target during open surgery. The system translates the tip location into a 3D-CT reconstructed image and an angiogram. The system worked as the core of a multimodality navigation system during surgery. The detection error was less than 5 mm, which proved sufficient for open microsurgery. The system was combined with a 3D-CT reconstruction system. It produces 3D images and cuts off the surface image at the point of the cursor, simulating surgical excision. The navigator controlled the location of the cutting cursor, thus establishing a real-time surgical simulation. When the angiogram was referred to, it became easy to identify bridging veins within a small operating field. Conclusion: The neuronavigator combines various diagnostic images into one data base and effectively guides the surgeon during surgery. (author)

  10. ECG-gated multislice spiral CT for diagnosis of acute pulmonary embolism

    International Nuclear Information System (INIS)

    Marten, K.; Engelke, C.; Funke, M.; Obenauer, S.; Baum, F.; Grabbe, E.

    2003-01-01

    AIM: The purpose of this study was to determine the feasibility of echocardiogram (ECG)-gated multi-slice CT angiography (MCTA) in patients with clinical suspicion of acute venous thromboembolism (VTE), to investigate the effect of ECG-gating on cardiac motion artefacts, and to determine the diagnostic reader agreement of ECG-gated MCTA in comparison with conventional MCTA. MATERIALS AND METHODS: Forty-eight consecutive patients were prospectively enrolled and randomly underwent ECG-gated (n=25, group 1) or non-ECG-gated (n=23, group 2) eight-slice pulmonary MCTA. Image data were evaluated by three independent chest radiologists with respect to the presence or absence of emboli at different arterial levels (main, lobar, segmental, and subsegmental arteries), and with regard to cardiac motion artefacts. Statistical tests used to calculate inter-observer agreement were weighted κ statistics, extended κ statistics and confidence indices indicating three-reader agreement accuracy. RESULTS: Twenty-seven patients (56.3%) were diagnosed to have pulmonary embolism (13 from group 1, 14 from group 2). Cardiac motion artefacts were significantly more frequent in group 2 (70% in group 2 versus 13% in group 1, p=0.0001). The overall diagnostic agreement was excellent with both MCTA techniques (three-reader confidence index for all vascular territories: 0.76 and 0.84 for groups 1 and 2, respectively (extended κ=0.69 and 0.78, respectively); three-reader confidence index for diagnosis of VTE: 0.94 and 0.85 for groups 1 and 2, respectively (extended κ=0.91 and 0.73, respectively), weighted κ=0.81-0.83 and 0.92-0.95 for groups 1 and 2, respectively, and did not differ significantly between the two groups. In addition there was no significant difference of inter-observer agreement in either group at any assessed pulmonary arterial level. CONCLUSION: ECG-gated pulmonary MCTA is feasible in patients with clinical suspicion of VTE. However, ECG-gated image acquisition did not

  11. Spiral CT dual-phase scanning for hepatocellular carcinoma: comparison study on the peripheral enhancement and pathology

    International Nuclear Information System (INIS)

    Chen Wenxia; Min Pengqiu; Zhou Xiangping; Song Bin; Liu Yan; Shen Mingen; Li Zhenlin; Yang Min

    2002-01-01

    Objective: To compare the peripheral enhancement features of hepatocellular carcinoma (HCC) lesions in arterial and portal venous phases with histopathology, and to study the histopathologic bases of peripheral enhancement of the HCC lesions and how it affects the biologic behavior and prognosis. Methods: Forty-two histopathologically proven HCC patients were included. First, an unenhanced scanning covering the whole liver was done, and followed by arterial and portal venous phase scanning. The delay time was 20 sec and 60 sec after the injecting of contrast media. the slides of 5 μm thickness were stained with HE and the standard immunoperoxidase method using the polyclonal antibody of factor VIII-related antigen (F8RA). The pseudo capsule of the lesion, tumor invasion of the pseudo capsule, and the number of positive stained tumor vessels in the pseudo capsule were evaluated. Results: Among the 42 cases, in arterial phase, the pseudo capsule of the HCC lesions was demonstrated as hyper-or hypo-attenuation in 13 and 8 cases, respectively, and no marked pseudo capsule was perceived in 21 cases. In portal venous phase, hyper-attenuated pseudo capsule was shown in 27 cases, hypo-attenuated pseudo capsule in 2 cases, and no pseudo capsule in 13 cases. On CT scans, daughter foci were showed in 14 cases, in which 9 cases were single and 5 of 42 patients, and tumor cells invaded the pseudo capsule in 16 caes among these cases. F8RA immunohistochemical staining showed that the pseudo capsule contained rich positive staining neo-vascular structure in 15 of 25 cases, and the other 10 cases had thick pseudo capsule but few neo-vascular structure. HE staining showed no marked pseudo capsule in 17 cases, in which 8 cases exhibited no clear border between the tumor tissue and liver parenchyma. Conclusion: The peripheral enhancement features of HCC on spiral CT dural-phase scanning could reflect the histopathologic characteristics and predict the biologic behavior and prognosis

  12. Alpha image reconstruction (AIR): A new iterative CT image reconstruction approach using voxel-wise alpha blending

    International Nuclear Information System (INIS)

    Hofmann, Christian; Sawall, Stefan; Knaup, Michael; Kachelrieß, Marc

    2014-01-01

    factor for contrast-resolution plots. Furthermore, the authors calculate the contrast-to-noise ratio with the low contrast disks and the authors compare the agreement of the reconstructions with the ground truth by calculating the normalized cross-correlation and the root-mean-square deviation. To evaluate the clinical performance of the proposed method, the authors reconstruct patient data acquired with a Somatom Definition Flash dual source CT scanner (Siemens Healthcare, Forchheim, Germany). Results: The results of the simulation study show that among the compared algorithms AIR achieves the highest resolution and the highest agreement with the ground truth. Compared to the reference FBP reconstruction AIR is able to reduce the relative pixel noise by up to 50% and at the same time achieve a higher resolution by maintaining the edge information from the basis images. These results can be confirmed with the patient data. Conclusions: To evaluate the AIR algorithm simulated and measured patient data of a state-of-the-art clinical CT system were processed. It is shown, that generating CT images through the reconstruction of weighting coefficients has the potential to improve the resolution noise trade-off and thus to improve the dose usage in clinical CT

  13. Image quality of iterative reconstruction in cranial CT imaging: comparison of model-based iterative reconstruction (MBIR) and adaptive statistical iterative reconstruction (ASiR).

    Science.gov (United States)

    Notohamiprodjo, S; Deak, Z; Meurer, F; Maertz, F; Mueck, F G; Geyer, L L; Wirth, S

    2015-01-01

    The purpose of this study was to compare cranial CT (CCT) image quality (IQ) of the MBIR algorithm with standard iterative reconstruction (ASiR). In this institutional review board (IRB)-approved study, raw data sets of 100 unenhanced CCT examinations (120 kV, 50-260 mAs, 20 mm collimation, 0.984 pitch) were reconstructed with both ASiR and MBIR. Signal-to-noise (SNR) and contrast-to-noise (CNR) were calculated from attenuation values measured in caudate nucleus, frontal white matter, anterior ventricle horn, fourth ventricle, and pons. Two radiologists, who were blinded to the reconstruction algorithms, evaluated anonymized multiplanar reformations of 2.5 mm with respect to depiction of different parenchymal structures and impact of artefacts on IQ with a five-point scale (0: unacceptable, 1: less than average, 2: average, 3: above average, 4: excellent). MBIR decreased artefacts more effectively than ASiR (p ASiR was 2 (p ASiR (p ASiR. As CCT is an examination that is frequently required, the use of MBIR may allow for substantial reduction of radiation exposure caused by medical diagnostics. • Model-Based iterative reconstruction (MBIR) effectively decreased artefacts in cranial CT. • MBIR reconstructed images were rated with significantly higher scores for image quality. • Model-Based iterative reconstruction may allow reduced-dose diagnostic examination protocols.

  14. Super-resolution reconstruction of 4D-CT lung data via patch-based low-rank matrix reconstruction

    Science.gov (United States)

    Fang, Shiting; Wang, Huafeng; Liu, Yueliang; Zhang, Minghui; Yang, Wei; Feng, Qianjin; Chen, Wufan; Zhang, Yu

    2017-10-01

    Lung 4D computed tomography (4D-CT), which is a time-resolved CT data acquisition, performs an important role in explicitly including respiratory motion in treatment planning and delivery. However, the radiation dose is usually reduced at the expense of inter-slice spatial resolution to minimize radiation-related health risk. Therefore, resolution enhancement along the superior-inferior direction is necessary. In this paper, a super-resolution (SR) reconstruction method based on a patch low-rank matrix reconstruction is proposed to improve the resolution of lung 4D-CT images. Specifically, a low-rank matrix related to every patch is constructed by using a patch searching strategy. Thereafter, the singular value shrinkage is employed to recover the high-resolution patch under the constraints of the image degradation model. The output high-resolution patches are finally assembled to output the entire image. This method is extensively evaluated using two public data sets. Quantitative analysis shows that the proposed algorithm decreases the root mean square error by 9.7%-33.4% and the edge width by 11.4%-24.3%, relative to linear interpolation, back projection (BP) and Zhang et al’s algorithm. A new algorithm has been developed to improve the resolution of 4D-CT. In all experiments, the proposed method outperforms various interpolation methods, as well as BP and Zhang et al’s method, thus indicating the effectivity and competitiveness of the proposed algorithm.

  15. Demonstration of the pulmonary interlobar fissures on multiplanar reformatted images with 64-slices spiral CT

    International Nuclear Information System (INIS)

    Wang Yafei; Chen Yerong; Shan Xiuhong; Tang Zhiyang; Ni Enzhen; Huang Hao; Wu Shuchun

    2009-01-01

    Objective: To determine the optimal orientation and slice thickness of reformatted images to visualize the interlobar fissures on multiplanar reformation (MPR) images and to recommend MPR imaging protocal for visualizing interlobar fissures in clinical practise. Methods: 64-slices CT scans of chest were obtained in 300 patients without pulmonary diseases. Axial, sagittal and coronal images were reformatted at 1, 2, 3, 7 mm slice thickness respectively from the raw volume data. Three experienced radiologists evaluated all of the MPR images in the lung window and compared the differences in visualization of the interlohar fissures among the three reformatted orientations and at the different slice thicknesses with Fisher test and Friedman test. Results: Fissures on sagittal MPR images using 1, 2, 3, and 7 mm reformatted slice thickness appeared as a fine line and the preference value analysis showed the MPR images with a 3 mm reformatted slice thickness is the best for visualizing the interlobar fissure. Compared to the sagittal orientation, the coronal was not as good and the axial was the worst among the three orientations. The coronal images with a 3 mm reformatted slice thickness were slightly inferior to sagittal images. The right horizontal fissures were observed as a fine line in all coronal image in 94.0% (282)of cases and in some of the images in 6.0% (18) of cases, the right oblique fissures were displayed as a fine line in coronal images in 2.3% (7) of cases and in some images in 85.0% (255) of cases, the left oblique fissures were displayed as a fine line in some coronal images in 35.7% (107) of cases and displayed as a coarse line in 64.3% (193) of cases. On axial MPR images using 3 mm reformation slice thickness, the right oblique fissures and the left oblique fissures were displayed as a fine line in some axial images in 79.3% (238) and 81.0% (243) of cases respectively, none of the images showed horizontal fissures as a fine line. There was

  16. The role of whole body spiral CT in the primary work-up of polytrauma patients - comparison with conventional radiography and abdominal sonography

    International Nuclear Information System (INIS)

    Albrecht, T.; Schlippenbach, J. von; Wolf, K.J.; Stahel, P.F.; Ertel, W.

    2004-01-01

    Purpose: To evaluate the role of routine 'whole body spiral CT' in the primary work-up of polytrauma patients for injuries of the thorax, abdomen and spine, and to compare the results with those of conventional radiography of the chest and spine and abdominal ultrasound. Materials and Methods: Fifty consecutive polytrauma patients underwent contrast-enhanced single slice spiral CT (5 mm collimation) from the vertex to the floor of the pelvis as part of the primary work-up after emergency room admission. Overlapping high resolution sections and sagittal reformations of the spine were obtained. Reports of additional chest radiographs (n=43), abdominal ultrasound examinations (n=47) and spine radiographs (n=36) performed in the emergency room were available for retrospective comparison. The 'final diagnoses', which served as the standard of reference, were taken from the patients' records using all information that became available until discharge or death, such as findings from further imaging, surgery and autopsy. Results: CT showed 109 (97%) of 112 thoracic and abdominal soft-tissue injuries. Relevant injuries missed were an early splenic laceration and an early pelvic hematoma, both of which became clinically apparent several hours later. There were 4 false positive CT findings. Conventional chest radiography demonstrated only 20% of thoracic and sonography 22% of abdominal injuries. Chest radiography and sonography produced 2 false-positive findings each. CT showed 66 (87%) of 76 vertebral fractures including all 19 unstable ones. CT missed 5 anterior vertebral body and 5 spinous/transverse process fractures. Conventional radiography found 71% of vertebral fractures including only 50% of the unstable one. (orig.)

  17. Investigation of influence of 16-slice spiral CT electrocardiogram-controlled dose modulation on exposure dosage and image quality of cardiac CT imaging under simulated fluctuant heart rate

    International Nuclear Information System (INIS)

    Yin Yan; Chen Jie; Chai Weiming; Hua Jia; Gao Na; Xu Jianrong; Shen Yun

    2008-01-01

    Objective: To investigate the influence of electrocardiogram (ECG)-controlled dose modulation on exposure dosage and image quality of cardiac CT imaging in a cardiac phantom with simulated fluctuant heart rate. Methods: The basal heart rate of the cardiac pulsating phantom was set as 60 bpm, the experimental situations were divided as 6 groups according to different heart rates. The cardiac imaging was performed on the cardiac phantom when the ECG-controlled dose modulation was firstly turned off. The exposure dosage of each scan sequence was documented. The standard deviation of the CT values of the phantom was measured on the central slice after coronal reformation of the raw data. The quality of 2D and 3D images were scored. Then cardiac imaging was performed when ECG modulation was on and set as four groups according to different modulation parameters. All the data were documented as before. The results from the five groups with and without ECG modulation current were analyzed by F test and comparative rank sum test using the statistical software SPSS 10.0. Results: Statistical analysis showed no significant difference (P>0.05) between the SNR of images (SD value was 27.78 and 26.30) from the groups that full mA output at wide reconstruction phase (69%-99%) when the heart rate was fluctuant(≥7.5 bpm). There was also no significant difference (P>0.05) between the quality of the 2D and 3D images. But there was a significant difference (P 12.5 bpm, the exposure dosage would increase obviously (from 0.6 to 1.7 mSv). Conclusion: For cardiac imaging with 16-slice row CT, the application of ECG modulated current can effectively reduce the exposure dosage without compromising the image quality even if heart rate was fluctuant. (authors)

  18. Techniques, clinical applications and limitations of 3D reconstruction in CT of the abdomen

    Energy Technology Data Exchange (ETDEWEB)

    Maher, Michael M.; Kalra, Mannudeep K.; Sahani, Dushyant V.; Perumpillichira, James J.; Rizzo, Stephania; Saini, Sanjay; Mueller, Peter R. [Massachusetts General Hospital and Harvard Medical School, Boston (United States)

    2004-03-15

    Enhanced z-axis coverage with thin overlapping slices in breath-hold acquisitions with multidetector CT (MDCT) has considerably enhanced the quality of multiplanar 3D reconstruction. This pictorial essay describes the improvements in 3D reconstruction and technical aspects of 3D reconstruction and rendering techniques available for abdominal imaging. Clinical applications of 3D imaging in abdomen including liver, pancreaticobiliary system, urinary and gastrointestinal tracts and imaging before and after transplantation are discussed. In addition, this article briefly discusses the disadvantages of this-slice acquisitions including increasing numbers of transverse images, which must be reviewed by the radiologist.

  19. Techniques, clinical applications and limitations of 3D reconstruction in CT of the abdomen

    International Nuclear Information System (INIS)

    Maher, Michael M.; Kalra, Mannudeep K.; Sahani, Dushyant V.; Perumpillichira, James J.; Rizzo, Stephania; Saini, Sanjay; Mueller, Peter R.

    2004-01-01

    Enhanced z-axis coverage with thin overlapping slices in breath-hold acquisitions with multidetector CT (MDCT) has considerably enhanced the quality of multiplanar 3D reconstruction. This pictorial essay describes the improvements in 3D reconstruction and technical aspects of 3D reconstruction and rendering techniques available for abdominal imaging. Clinical applications of 3D imaging in abdomen including liver, pancreaticobiliary system, urinary and gastrointestinal tracts and imaging before and after transplantation are discussed. In addition, this article briefly discusses the disadvantages of this-slice acquisitions including increasing numbers of transverse images, which must be reviewed by the radiologist

  20. A fast iterative soft-thresholding algorithm for few-view CT reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Junfeng; Mou, Xuanqin; Zhang, Yanbo [Jiaotong Univ., Xi' an (China). Inst. of Image Processing and Pattern Recognition

    2011-07-01

    Iterative soft-thresholding algorithms with total variation regularization can produce high-quality reconstructions from few views and even in the presence of noise. However, these algorithms are known to converge quite slowly, with a proven theoretically global convergence rate O(1/k), where k is iteration number. In this paper, we present a fast iterative soft-thresholding algorithm for few-view fan beam CT reconstruction with a global convergence rate O(1/k{sup 2}), which is significantly faster than the iterative soft-thresholding algorithm. Simulation results demonstrate the superior performance of the proposed algorithm in terms of convergence speed and reconstruction quality. (orig.)

  1. Transthoracic CT-guided biopsy with multiplanar reconstruction image improves diagnostic accuracy of solitary pulmonary nodules

    International Nuclear Information System (INIS)

    Ohno, Yoshiharu; Hatabu, Hiroto; Takenaka, Daisuke; Imai, Masatake; Ohbayashi, Chiho; Sugimura, Kazuro

    2004-01-01

    Objective: To evaluate the utility of multiplanar reconstruction (MPR) image for CT-guided biopsy and determine factors of influencing diagnostic accuracy and the pneumothorax rate. Materials and methods: 390 patients with 396 pulmonary nodules underwent transthoracic CT-guided aspiration biopsy (TNAB) and transthoracic CT-guided cutting needle core biopsy (TCNB) as follows: 250 solitary pulmonary nodules (SPNs) underwent conventional CT-guided biopsy (conventional method), 81 underwent CT-fluoroscopic biopsy (CT-fluoroscopic method) and 65 underwent conventional CT-guided biopsy in combination with MPR image (MPR method). Success rate, overall diagnostic accuracy, pneumothorax rate and total procedure time were compared in each method. Factors affecting diagnostic accuracy and pneumothorax rate of CT-guided biopsy were statistically evaluated. Results: Success rates (TNAB: 100.0%, TCNB: 100.0%) and overall diagnostic accuracies (TNAB: 96.9%, TCNB: 97.0%) of MPR were significantly higher than those using the conventional method (TNAB: 87.6 and 82.4%, TCNB: 86.3 and 81.3%) (P<0.05). Diagnostic accuracy were influenced by biopsy method, lesion size, and needle path length (P<0.05). Pneumothorax rate was influenced by pathological diagnostic method, lesion size, number of punctures and FEV1.0% (P<0.05). Conclusion: The use of MPR for CT-guided lung biopsy is useful for improving diagnostic accuracy with no significant increase in pneumothorax rate or total procedure time

  2. Effect of hybrid iterative reconstruction technique on quanti