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Sample records for ct visible internal

  1. Invisible fat on CT: making it visible by MRI.

    Science.gov (United States)

    Ünal, Emre; Karaosmanoğlu, Ali Devrim; Akata, Deniz; Özmen, Mustafa Nasuh; Karçaaltıncaba, Muşturay

    2016-01-01

    Presence of fat in a lesion significantly narrows the differential diagnosis. Small quantities of macroscopic fat and intracellular fat are invisible on computed tomography (CT) and ultrasonography. Magnetic resonance imaging (MRI) can reveal any fatty change in a lesion and can also differentiate macroscopic fat from intracellular and intravoxel fat. Hypodensity on CT may be a sign of invisible fat and MRI can help to diagnose even minute amounts of fat in liver, pancreas, adrenal, musculoskeletal, and omental pseudolesions and lesions. This article will review the superiority of MRI over CT in demonstrating fat in abdominal lesions.

  2. CT-Guided Biopsy of Small Liver Lesions: Visibility, Artifacts, and Corresponding Diagnostic Accuracy

    International Nuclear Information System (INIS)

    Stattaus, Joerg; Kuehl, Hilmar; Ladd, Susanne; Schroeder, Tobias; Antoch, Gerald; Baba, Hideo A.; Barkhausen, Joerg; Forsting, Michael

    2007-01-01

    Purpose. Our study aimed to determine the visibility of small liver lesions during CT-guided biopsy and to assess the influence of lesion visibility on biopsy results. Material and Methods. Fifty patients underwent CT-guided core biopsy of small focal liver lesions (maximum diameter, 3 cm); 38 biopsies were performed using noncontrast CT, and the remaining 12 were contrast-enhanced. Visibility of all lesions was graded on a 4-point-scale (0 = not visible, 1 = poorly visible, 2 = sufficiently visible, 3 = excellently visible) before and during biopsy (with the needle placed adjacent to and within the target lesion). Results. Forty-three biopsies (86%) yielded diagnostic results, and seven biopsies were false-negative. In noncontrast biopsies, the rate of insufficiently visualized lesions (grades 0-1) increased significantly during the procedure, from 10.5% to 44.7%, due to needle artifacts. This resulted in more (17.6%) false-negative biopsy results compared to lesions with good visualization (4.8%), although this difference lacks statistical significance. Visualization impairment appeared more often with an intercostal or subcostal vs. an epigastric access and with a subcapsular vs. a central lesion location, respectively. With contrast-enhanced biopsy the visibility of hepatic lesions was only temporarily improved, with a risk of complete obscuration in the late phase. Conclusion. In conclusion, visibility of small liver lesions diminished significantly during CT-guided biopsy due to needle artifacts, with a fourfold increased rate of insufficiently visualized lesions and of false-negative histological results. Contrast enhancement did not reveal better results

  3. Performance evaluation of X-ray CT using visible scintillation light

    International Nuclear Information System (INIS)

    Kodama, Kiyoyuki; Hamada, Minoru; Suzuki, Tamotsu; Hashimoto, Masatoshi; Hanada, Takashi; Ide, Tatsuya; Maruyama, Koichi

    2004-01-01

    We proposed a new method of performance evaluation for X-ray CT using visible scintillation light and examined its usefulness in this study. When we scanned a plastic scintillator disk in a gantry opening of the X-ray CT, we could observe visible scintillation light. The rotation of the light-emitting area of the disk corresponded to that of the X-ray tube. We were able to record the scintillation light by digital video camera. By analyzing the area of visible scintillation light, the rotation speed of the X-ray tube, angular spread of the X-ray beam, uniformity of the incident X-rays, and change in X-ray energy were measured. No other method is available to obtain the above parameters of X-ray CT during a single CT scan. In the measurements of the uniformity of incident X-rays and change of X-ray energy, our method showed good accuracy in detecting the attenuation caused by the couch between the X-ray tube and the plastic scintillator disc. The proposed method is inexpensive and easy-to-use. We conclude that the method is a useful tool for performance evaluation as well as a maintenance tool for X-ray CT. (author)

  4. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... to a CD or DVD. CT images of internal organs, bones, soft tissue and blood vessels provide ... clicking and whirring sounds as the CT scanner's internal parts, not usually visible to you, revolve around ...

  5. A new technique for localization of hepatic tumors that are poorly visible with CT fluoroscopy

    International Nuclear Information System (INIS)

    Arrive, Lionel; Azizi, Louisa; Monnier-Cholley, Laurence; Lewin, Maite; Tubiana, Jean-Michel; Rosmorduc, Olivier; Beaussier, Marc

    2006-01-01

    The purpose of this study was to report a new technique for localization of hepatic tumors that are poorly visible with CT fluoroscopy. Forty-three hepatocellular carcinomas were not visible with CT fluoroscopy. A 22-gauge Chiba end-hole needle was inserted in the approximate location of a lesion estimated on the basis of anatomical landmarks demonstrated on both previous MR and CT images. We injected 3 ml of a mixture of nonionic contrast material and saline solution. Following the first injection, contrast solution filled the hepatic lesion in 29 of 43 cases. In 8 of 43 cases, contrast solution was distributed in the normal surrounding liver. In 7 of these 8 cases, repositioning allowed us to adjust the needle in the tumor. In the other 6 of 43 cases, contrast solution spread within capsule or pseudocapsule (pattern 3). In all 6 cases, repositioning allowed to adjust the needle in the tumor. This new technique allows an accurate localization of hepatic tumors that are poorly visible with CT fluoroscopy. (orig.)

  6. Renal angiomyolipoma without visible fat. Can we make the diagnosis using CT and MRI?

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Robert S.; McInnes, Matthew D.F.; Schieda, Nicola [The University of Ottawa, Department of Medical Imaging, The Ottawa Hospital, Ottawa, Ontario (Canada); Flood, Trevor A. [The University of Ottawa, Department of Anatomical Pathology, The Ottawa Hospital, Ottawa, Ontario (Canada); Lavallee, Luke T. [The University of Ottawa, Department of Surgery, Division of Urology, The Ottawa Hospital, Ottawa, Ontario (Canada)

    2018-02-15

    Renal angiomyolipomas without visible fat (AML.wovf) are benign masses that are incidentally discovered mainly in women. AML.wovf are typically homogeneously hyperdense on unenhanced CT without calcification or haemorrhage. Unenhanced CT pixel analysis is not useful for diagnosis. AML.wovf are characteristically homogeneously hypointense on T2-weighted (T2W)-MRI and apparent diffusion coefficient (ADC) maps. Despite early reports, only a minority of AML.wovf show signal intensity drop on chemical-shift MRI due to microscopic fat. AML.wovf most commonly show avid early enhancement with washout kinetics at contrast-enhanced CT and MRI. The combination of homogeneously low T2W and/or ADC signal intensity with avid early enhancement and washout is highly accurate for diagnosis of AML.wovf. (orig.)

  7. 4D CT sorting based on patient internal anatomy

    Science.gov (United States)

    Li, Ruijiang; Lewis, John H.; Cerviño, Laura I.; Jiang, Steve B.

    2009-08-01

    Respiratory motion during free-breathing computed tomography (CT) scan may cause significant errors in target definition for tumors in the thorax and upper abdomen. A four-dimensional (4D) CT technique has been widely used for treatment simulation of thoracic and abdominal cancer radiotherapy. The current 4D CT techniques require retrospective sorting of the reconstructed CT slices oversampled at the same couch position. Most sorting methods depend on external surrogates of respiratory motion recorded by extra instruments. However, respiratory signals obtained from these external surrogates may not always accurately represent the internal target motion, especially when irregular breathing patterns occur. We have proposed a new sorting method based on multiple internal anatomical features for multi-slice CT scan acquired in the cine mode. Four features are analyzed in this study, including the air content, lung area, lung density and body area. We use a measure called spatial coherence to select the optimal internal feature at each couch position and to generate the respiratory signals for 4D CT sorting. The proposed method has been evaluated for ten cancer patients (eight with thoracic cancer and two with abdominal cancer). For nine patients, the respiratory signals generated from the combined internal features are well correlated to those from external surrogates recorded by the real-time position management (RPM) system (average correlation: 0.95 ± 0.02), which is better than any individual internal measures at 95% confidence level. For these nine patients, the 4D CT images sorted by the combined internal features are almost identical to those sorted by the RPM signal. For one patient with an irregular breathing pattern, the respiratory signals given by the combined internal features do not correlate well with those from RPM (correlation: 0.68 ± 0.42). In this case, the 4D CT image sorted by our method presents fewer artifacts than that from the RPM signal. Our

  8. Making the invisible visible: improving conspicuity of noncalcified gallstones using dual-energy CT.

    Science.gov (United States)

    Uyeda, Jennifer W; Richardson, Ian J; Sodickson, Aaron D

    2017-12-01

    To determine whether virtual monochromatic imaging (VMI) increases detectability of noncalcified gallstones on dual-energy CT (DECT) compared with conventional CT imaging. This retrospective IRB-approved, HIPAA-compliant study included consecutive patients who underwent DECT of the abdomen in the Emergency Department during a 30-month period (July 1, 2013-December 31, 2015), with a comparison US or MR within 1-year. 51 patients (36F, 15M; mean age 52 years) fulfilled the inclusion criteria. All DECT were acquired on a dual-source 128 × 2 slice scanner using either 80/Sn140 or 100/Sn140 kVp pairs. Source images at high and low kVp were used for DE post-processing with VMI. Within 3 mm reconstructed images, regions of interest of 0.5 cm 2 were placed on noncalcified gallstones and bile to record hounsfield units (HU) at VMI energy levels ranging between 40 and 190 keV. Noncalcified gallstones uniformly demonstrated lowest HU at 40 keV and increase at higher keV; the HU of bile varied at higher keV. Few of the noncalcified stones are visible at 70 keV (simulating a conventional 120 kVp scan), with measured contrast (bile-stone HU difference) 20 HU in 2%. Contrast was maximal at 40 keV, where 100% demonstrated >20 HU difference from surrounding bile, 75% >44 HU difference, and 50% >60 HU difference. A paired t test demonstrated a significant difference (p < 0.0001) between this stone-bile contrast at 40 vs. 70 keV and 70 vs. 190 keV. Low keV virtual monochromatic imaging increased conspicuity of noncalcified gallstones, improving their detectability.

  9. The diagnosis of internal disc disruption with CT discography

    International Nuclear Information System (INIS)

    Liu Miao; Chen Xingcan; Li Xiaohong; Pan Yongqin

    2008-01-01

    Objective: To study the value of diagnosis for internal disc disruption (IDD)with CT discography(CTD). Methods: 42 discs of 32 patients showing no disc herniation on CT or MRI, but suffering from chronic low back pain, were undertaken CTD to work out the types of CTD with correlation between contrast medium dosages and the induction of pain. Results: CTD demonstrated 4 types of IDD which was individually correlated with the contrast dosages and induced pain; furthermore the dosages for positive and negative disc cases showed significant differece (P<0.01). Conclusions: CTD can show the direct sign of internal disc disruption, providing more information than conventional discography. (authors)

  10. Localized intrahepatic bile duct dilatation without a visible mass or stone as depicted on CT images: findings of malignancy prediction

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Ju Wan; Kim, Gab Chul; Jeong, Han Young; Lee, Hui Joong; Lee, Jae Hyuck; Ryeom, Hun Kyu [Kyungpook National University Hospital, Daegu (Korea, Republic of); Kim, Jong Yeol [Kumi Cha Medical Center, Collge of Medicine, Pochon CHA University, Kumi (Korea, Republic of)

    2008-09-15

    This study was preformed to evaluate factors that can predict the presence of a malignancy for localized intrahepatic bile duct dilatation without a visible mass or stone as depicted on CT images. A total of 29 patients (male: 16, female: 13) who had localized intrahepatic bile duct dilatation without a visible mass, stone or injury as depicted on CT images were included in the study. A history of extrahepatic malignancy and biliary stone disease, tumor marker levels, CT findings of the intrahepatic bile duct and associated findings were reviewed. The findings were analyzed between two groups (patients with a malignancy and patients with benign disease) on follow-up. In 29 patient, 11 patients had malignant lesions (four metastases and seven cholangiocarcinomas). The history of an extrahepatic malignancy and the shape of an intrahepatic duct obstruction or stenosis as seen on CT were significantly correlated with the results between the benign and malignant group of patients. The follow-up results of the malignant group of patients indicated that for six patients who had developed a new mass, one patient each showed aggravation of ductal dilatation and thickening of the ductal wall. When a patient with localized intrahepatic bile duct dilatation without a definite cause has a history of an extrahepatic malignancy or shows abrupt tapering or irregular narrowing on CT images, short-term follow-up should be performed. The patient should be investigated carefully for mass formation or a change of the dilated bile duct due to a possibility of malignant ductal dilatation.

  11. Localized intrahepatic bile duct dilatation without a visible mass or stone as depicted on CT images: findings of malignancy prediction

    International Nuclear Information System (INIS)

    Choi, Ju Wan; Kim, Gab Chul; Jeong, Han Young; Lee, Hui Joong; Lee, Jae Hyuck; Ryeom, Hun Kyu; Kim, Jong Yeol

    2008-01-01

    This study was preformed to evaluate factors that can predict the presence of a malignancy for localized intrahepatic bile duct dilatation without a visible mass or stone as depicted on CT images. A total of 29 patients (male: 16, female: 13) who had localized intrahepatic bile duct dilatation without a visible mass, stone or injury as depicted on CT images were included in the study. A history of extrahepatic malignancy and biliary stone disease, tumor marker levels, CT findings of the intrahepatic bile duct and associated findings were reviewed. The findings were analyzed between two groups (patients with a malignancy and patients with benign disease) on follow-up. In 29 patient, 11 patients had malignant lesions (four metastases and seven cholangiocarcinomas). The history of an extrahepatic malignancy and the shape of an intrahepatic duct obstruction or stenosis as seen on CT were significantly correlated with the results between the benign and malignant group of patients. The follow-up results of the malignant group of patients indicated that for six patients who had developed a new mass, one patient each showed aggravation of ductal dilatation and thickening of the ductal wall. When a patient with localized intrahepatic bile duct dilatation without a definite cause has a history of an extrahepatic malignancy or shows abrupt tapering or irregular narrowing on CT images, short-term follow-up should be performed. The patient should be investigated carefully for mass formation or a change of the dilated bile duct due to a possibility of malignant ductal dilatation

  12. Ultrafast CT scanning of an oak log for internal defects

    Science.gov (United States)

    Francis G. Wagner; Fred W. Taylor; Douglas S. Ladd; Charles W. McMillin; Fredrick L. Roder

    1989-01-01

    Detecting internal defects in sawlogs and veneer logs with computerized tomographic (CT) scanning is possible, but has been impractical due to the long scanning time required. This research investigated a new scanner able to acquire 34 cross-sectional log scans per second. This scanning rate translates to a linear log feed rate of 85 feet (25.91 m) per minute at one...

  13. Cerebellopontine angle and internal auditory canal: neurovascular anatomy on gas CT cisternograms

    International Nuclear Information System (INIS)

    Bird, C.R.; Hasso, A.N.; Drayer, B.P.; Hinshaw, D.B. Jr.; Thompson, J.R.

    1985-01-01

    The authors reviewed 103 normal gas CT cisternograms to delineate the appearance of normal neurovascular structures in the cerebellopontine angle (CPA) and internal auditory canal (IAC). Cranial nerves VII and VIII were identified in the CPA in 97% of cases, either separately (53%) or as a bundle (44%). Intracanalicular branches of the VIIIth cranial nerve were identified in 20% of cases, and cranial nerve V was visualized in the CPA in 14%. The characteristic vascular loop, usually the anterior inferior cerebellar artery, was visible in 35% of cases, and, in 22% of visualized cases, was in an intracanalicular location. In 10% of cases, greater than 66% of the IAC was occupied by the neurovascular bundle. Familiarity with the normal anatomy and variations seen on gas CT cisternograms is necessary to prevent false-positive interpretations

  14. Coronary artery visibility in free-breathing young children on non-gated chest CT: impact of temporal resolution

    Energy Technology Data Exchange (ETDEWEB)

    Bridoux, Alexandre; Hutt, Antoine; Faivre, Jean-Baptiste; Pagniez, Julien; Remy, Jacques; Remy-Jardin, Martine [CHRU et Universite de Lille, Department of Thoracic Imaging, Hospital Calmette (EA 2694), 59037 Lille Cedex (France); Flohr, Thomas [Siemens Healthcare, Department of Research and Development in CT, Forchheim (Germany); Duhamel, Alain [Universite de Lille, Department of Biostatistics, Lille (France)

    2015-11-15

    Dual-source CT allows scanning of the chest with high pitch and high temporal resolution, which can improve the detection of proximal coronary arteries in infants and young children when scanned without general anesthesia, sedation or beta-blockade. To compare coronary artery visibility between higher and standard temporal resolution. We analyzed CT images in 93 children who underwent a standard chest CT angiographic examination with reconstruction of images with a temporal resolution of 75 ms (group 1) and 140 ms (group 2). The percentage of detected coronary segments was higher in group 1 than in group 2 when considering all segments (group 1: 27%; group 2: 24%; P = 0.0004) and proximal segments (group 1: 37%; group 2: 32%; P = 0.0006). In both groups, the highest rates of detection were observed for the left main coronary artery (S1) (group 1: 65%; group 2: 58%) and proximal left anterior descending coronary artery (S2) (group 1: 43%; group 2: 42%). Higher rates of detection were seen in group 1 for the left main coronary artery (P = 0.03), proximal right coronary artery (P = 0.01), proximal segments of the left coronary artery (P = 0.02) and proximal segments of the left and right coronary arteries (P = 0.0006). Higher temporal resolution improved the visibility of proximal coronary arteries in pediatric chest CT. (orig.)

  15. Distribution of internal mammary lymphadenopathy in breast carcinoma: CT appraisal

    International Nuclear Information System (INIS)

    Scatarige, J.C.; Fishman, E.K.; Zinreich, E.S.; Almaraz, R.

    1987-01-01

    The authors studied the anatomic distribution of enlarged internal mammary lymph nodes in breast carcinoma by reviewing thoracic CT examinations in 219 women with operable, advanced or recurrent disease. Enlarged internal mammary lymph nodes were observed in 45 patients (20.5%); they were unilateral in 32 and bilateral in 13. Lymphadenopathy was limited to one anterior intercostal space in 43%, two spaces in 26%, and three or more species in 31%. Dominant modal disease was centered at the first anterior intercostal space in 14%, the second space in 60%, and the third space in 26%. Isolated adenopathy in the fourth intercostal space was not observed. The authors' data concur with current surgical practice when internal mammary lymph nodes are sampled. Implications for preoperative imaging strategy are discussed

  16. A technique of using gated-CT images to determine internal target volume (ITV) for fractionated stereotactic lung radiotherapy

    International Nuclear Information System (INIS)

    Jin Jianyue; Ajlouni, Munther; Chen Qing; Yin, Fang-Fang; Movsas, Benjamin

    2006-01-01

    Background and purpose: To develop and evaluate a technique and procedure of using gated-CT images in combination with PET image to determine the internal target volume (ITV), which could reduce the planning target volume (PTV) with adequate target coverage. Patients and methods: A skin marker-based gating system connected to a regular single slice CT scanner was used for this study. A motion phantom with adjustable motion amplitude was used to evaluate the CT gating system. Specifically, objects of various sizes/shapes, considered as virtual tumors, were placed on the phantom to evaluate the number of phases of gated images required to determine the ITV while taking into account tumor size, shape and motion. A procedure of using gated-CT and PET images to define ITV for patients was developed and was tested in patients enrolled in an IRB approved protocol. Results: The CT gating system was capable of removing motion artifacts for target motion as large as 3-cm when it was gated at optimal phases. A phantom study showed that two gated-CT scans at the end of expiration and the end of inspiration would be sufficient to determine the ITV for tumor motion less than 1-cm, and another mid-phase scan would be required for tumors with 2-cm motion, especially for small tumors. For patients, the ITV encompassing visible tumors in all sets of gated-CT and regular spiral CT images seemed to be consistent with the target volume determined from PET images. PTV expanded from the ITV with a setup uncertainty margin had less volume than PTVs from spiral CT images with a 10-mm generalized margin or an individualized margin determined at fluoroscopy. Conclusions: A technique of determining the ITV using gated-CT images was developed and was clinically implemented successfully for fractionated stereotactic lung radiotherapy

  17. Spectral CT with metal artifacts reduction software for improvement of tumor visibility in the vicinity of gold fiducial markers.

    Science.gov (United States)

    Brook, Olga R; Gourtsoyianni, Sofia; Brook, Alexander; Mahadevan, Anand; Wilcox, Carol; Raptopoulos, Vassilios

    2012-06-01

    To evaluate spectral computed tomography (CT) with metal artifacts reduction software (MARS) for reduction of metal artifacts associated with gold fiducial seeds. Thirteen consecutive patients with 37 fiducial seeds implanted for radiation therapy of abdominal lesions were included in this HIPAA-compliant, institutional review board-approved prospective study. Six patients were women (46%) and seven were men (54%). The mean age was 61.1 years (median, 58 years; range, 29-78 years). Spectral imaging was used for arterial phase CT. Images were reconstructed with and without MARS in axial, coronal, and sagittal planes. Two radiologists independently reviewed reconstructions and selected the best image, graded the visibility of the tumor, and assessed the amount of artifacts in all planes. A linear-weighted κ statistic and Wilcoxon signed-rank test were used to assess interobserver variability. Histogram analysis with the Kolmogorov-Smirnov test was used for objective evaluation of artifacts reduction. Fiducial seeds were placed in pancreas (n = 5), liver (n = 7), periportal lymph nodes (n = 1), and gallbladder bed (n = 1). MARS-reconstructed images received a better grade than those with standard reconstruction in 60% and 65% of patients by the first and second radiologist, respectively. Tumor visibility was graded higher with standard versus MARS reconstruction (grade, 3.7 ± 1.0 vs 2.8 ± 1.1; P = .001). Reduction of blooming was noted on MARS-reconstructed images (P = .01). Amount of artifacts, for both any and near field, was significantly smaller on sagittal and coronal MARS-reconstructed images than on standard reconstructions (P MARS-reconstructed images than on standard reconstructions (P MARS than with standard reconstruction in 35 of 37 patients (P MARS improved tumor visibility in the vicinity of gold fiducial seeds.

  18. Probabilistic Nowcasting of Low-Visibility Procedure States at Vienna International Airport During Cold Season

    Science.gov (United States)

    Kneringer, Philipp; Dietz, Sebastian J.; Mayr, Georg J.; Zeileis, Achim

    2018-04-01

    Airport operations are sensitive to visibility conditions. Low-visibility events may lead to capacity reduction, delays and economic losses. Different levels of low-visibility procedures (lvp) are enacted to ensure aviation safety. A nowcast of the probabilities for each of the lvp categories helps decision makers to optimally schedule their operations. An ordered logistic regression (OLR) model is used to forecast these probabilities directly. It is applied to cold season forecasts at Vienna International Airport for lead times of 30-min out to 2 h. Model inputs are standard meteorological measurements. The skill of the forecasts is accessed by the ranked probability score. OLR outperforms persistence, which is a strong contender at the shortest lead times. The ranked probability score of the OLR is even better than the one of nowcasts from human forecasters. The OLR-based nowcasting system is computationally fast and can be updated instantaneously when new data become available.

  19. Visibility of the origin and proximal course of coronary arteries on non-ECG-gated heart CT in patients with congenital heart disease

    International Nuclear Information System (INIS)

    Goo, Hyun Woo; Park, In-Sook; Ko, Jae Kon; Kim, Young Hwee; Seo, Dong-Man; Yun, Tae-Jin; Park, Jeong-Jun

    2005-01-01

    There is little information on the ability of non-ECG-gated cardiac CT to demonstrate the coronary arteries of children. To evaluate the visibility of the origin and proximal course of coronary arteries on non-ECG-gated cardiac CT, in which the coronary artery was not of primary diagnostic concern, in children with congenital heart disease. From December 2002 to March 2004, 126 cardiac CT examinations from 104 children (median age 11 months; age range 1 day to 15 years) were evaluated. All patients had ventriculo-arterial concordance and no malformations of the great arteries; those with coronary artery anomalies were excluded. Contrast-enhanced 16-slice spiral CT was performed without ECG-gating and multiplanar images for coronary arteries were obtained. The visibility of coronary artery origins was graded on a three-point scale, while nine segments of the arteries were graded on a four-point scale. CT images in which it was possible to trace the coronary arteries were considered diagnostic. The visibility of each whole coronary artery and the origins and proximal four segments of coronary arteries were calculated. The visibility of coronary arteries was also correlated with patient age. The percentage of CT images of diagnostic quality was 49.3% for the whole coronary artery and 81.7% for the origins and proximal four segments. There was a significant positive correlation between the visibility of coronary arteries and age. Non-ECG-gated cardiac CT, in which the coronary artery is not of primary diagnostic concern, is frequently able to visualize the origin and proximal course of coronary arteries and may be helpful in detecting coronary artery anomalies in children with congenital heart disease. (orig.)

  20. Rapid progression of massive hepatic calcification visible by CT: The case of a dialysed patient

    International Nuclear Information System (INIS)

    Gorycki, T.; Szarmach, A.; Szymanska-Dubowik, A.

    2008-01-01

    There have been single reported cases of patients with diffuse hepatic calcifications revealed 4-36 months after the first examination in the course of hemodialysis-treated renal failure, severe heart failure, shock liver, primary amyloidosis, or corticosteroid administration. In the presented case, many different factors for liver calcification and dynamic tomographic manifestation are seen. A 23-year-old man who was on hemodialysis because of acute renal failure after a motor vehicle accident (multiorgan trauma) with occurrence of hypovolemic shock was admitted to the hospital's intensive care unit presenting with clostridial infection of the lower extremities. During his stay at a prior hospital, ultrasonography did not reveal hepatic lesions. He underwent 22 sessions of treatment with hyperbaric oxygen as well as several necrectomies and amputation of both lower limbs. Abdominal CT performed three weeks after the accident demonstrated diffuse hepatic calcification which was later confirmed during autopsy. Liver parenchymal calcifications may be related to elevated calcium-phosphorus products in the uremic state and after multiple bone fractures and possible ischemic liver injury. Although a definitive explanation for the unusually short time of the appearance of liver calcification was not obtained, it may be related to many factors acting synergistically. Hyperbaric oxygen treatment is of unknown significance in this process. CT plays a basic role in detecting and assessing liver calcifications forming both diffuse lesions and those with well-defined borders. Diffuse calcifications revealed by CT must be analyzed together with the patient's history, especially considering renal and heart failure, bone fractures, states of shock, and treatment. Diffuse liver calcifications in these patients after respiratory therapy and transfusions when no subcapsular hematoma is found should be considered of metabolic origin. (author)

  1. TH-E-17A-01: Internal Respiratory Surrogate for 4D CT Using Fourier Transform and Anatomical Features

    Energy Technology Data Exchange (ETDEWEB)

    Hui, C; Suh, Y; Robertson, D; Pan, T; Das, P; Crane, C; Beddar, S [MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-15

    Purpose: To develop a novel algorithm to generate internal respiratory signals for sorting of four-dimensional (4D) computed tomography (CT) images. Methods: The proposed algorithm extracted multiple time resolved features as potential respiratory signals. These features were taken from the 4D CT images and its Fourier transformed space. Several low-frequency locations in the Fourier space and selected anatomical features from the images were used as potential respiratory signals. A clustering algorithm was then used to search for the group of appropriate potential respiratory signals. The chosen signals were then normalized and averaged to form the final internal respiratory signal. Performance of the algorithm was tested in 50 4D CT data sets and results were compared with external signals from the real-time position management (RPM) system. Results: In almost all cases, the proposed algorithm generated internal respiratory signals that visibly matched the external respiratory signals from the RPM system. On average, the end inspiration times calculated by the proposed algorithm were within 0.1 s of those given by the RPM system. Less than 3% of the calculated end inspiration times were more than one time frame away from those given by the RPM system. In 3 out of the 50 cases, the proposed algorithm generated internal respiratory signals that were significantly smoother than the RPM signals. In these cases, images sorted using the internal respiratory signals showed fewer artifacts in locations corresponding to the discrepancy in the internal and external respiratory signals. Conclusion: We developed a robust algorithm that generates internal respiratory signals from 4D CT images. In some cases, it even showed the potential to outperform the RPM system. The proposed algorithm is completely automatic and generally takes less than 2 min to process. It can be easily implemented into the clinic and can potentially replace the use of external surrogates.

  2. TH-E-17A-01: Internal Respiratory Surrogate for 4D CT Using Fourier Transform and Anatomical Features

    International Nuclear Information System (INIS)

    Hui, C; Suh, Y; Robertson, D; Pan, T; Das, P; Crane, C; Beddar, S

    2014-01-01

    Purpose: To develop a novel algorithm to generate internal respiratory signals for sorting of four-dimensional (4D) computed tomography (CT) images. Methods: The proposed algorithm extracted multiple time resolved features as potential respiratory signals. These features were taken from the 4D CT images and its Fourier transformed space. Several low-frequency locations in the Fourier space and selected anatomical features from the images were used as potential respiratory signals. A clustering algorithm was then used to search for the group of appropriate potential respiratory signals. The chosen signals were then normalized and averaged to form the final internal respiratory signal. Performance of the algorithm was tested in 50 4D CT data sets and results were compared with external signals from the real-time position management (RPM) system. Results: In almost all cases, the proposed algorithm generated internal respiratory signals that visibly matched the external respiratory signals from the RPM system. On average, the end inspiration times calculated by the proposed algorithm were within 0.1 s of those given by the RPM system. Less than 3% of the calculated end inspiration times were more than one time frame away from those given by the RPM system. In 3 out of the 50 cases, the proposed algorithm generated internal respiratory signals that were significantly smoother than the RPM signals. In these cases, images sorted using the internal respiratory signals showed fewer artifacts in locations corresponding to the discrepancy in the internal and external respiratory signals. Conclusion: We developed a robust algorithm that generates internal respiratory signals from 4D CT images. In some cases, it even showed the potential to outperform the RPM system. The proposed algorithm is completely automatic and generally takes less than 2 min to process. It can be easily implemented into the clinic and can potentially replace the use of external surrogates

  3. Monitoring internal organ motion with continuous wave radar in CT

    International Nuclear Information System (INIS)

    Pfanner, Florian; Maier, Joscha; Allmendinger, Thomas; Flohr, Thomas; Kachelrieß, Marc

    2013-01-01

    Purpose: To avoid motion artifacts in medical imaging or to minimize the exposure of healthy tissues in radiation therapy, medical devices are often synchronized with the patient's respiratory motion. Today's respiratory motion monitors require additional effort to prepare the patients, e.g., mounting a motion belt or placing an optical reflector on the patient's breast. Furthermore, they are not able to measure internal organ motion without implanting markers. An interesting alternative to assess the patient's organ motion is continuous wave radar. The aim of this work is to design, implement, and evaluate such a radar system focusing on application in CT.Methods: The authors designed a radar system operating in the 860 MHz band to monitor the patient motion. In the intended application of the radar system, the antennas are located close to the patient's body inside the table of a CT system. One receive and four transmitting antennas are used to avoid the requirement of exact patient positioning. The radar waves propagate into the patient's body and are reflected at tissue boundaries, for example at the borderline between muscle and adipose tissue, or at the boundaries of organs. At present, the authors focus on the detection of respiratory motion. The radar system consists of the hardware mentioned above as well as of dedicated signal processing software to extract the desired information from the radar signal. The system was evaluated using simulations and measurements. To simulate the radar system, a simulation model based on radar and wave field equations was designed and 4D respiratory-gated CT data sets were used as input. The simulated radar signals and the measured data were processed in the same way. The radar system hardware and the signal processing algorithms were tested with data from ten volunteers. As a reference, the respiratory motion signal was recorded using a breast belt simultaneously with the radar measurements.Results: Concerning the

  4. Cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS flat panel detector: Visibility of simulated microcalcifications

    OpenAIRE

    Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen; Wang, Tianpeng; Shaw, Chris C.

    2013-01-01

    Purpose: To measure and investigate the improvement of microcalcification (MC) visibility in cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS/CsI flat panel detector (Dexela 2923, Perkin Elmer).

  5. Prospective ECG-triggered axial CT at 140-kV tube voltage improves coronary in-stent restenosis visibility at a lower radiation dose compared with conventional retrospective ECG-gated helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Horiguchi, Jun; Fujioka, Chikako; Kiguchi, Masao; Kohno, Shingo [Hiroshima University Hospital, Department of Clinical Radiology, Hiroshima (Japan); Yamamoto, Hideya; Kitagawa, Toshiro [Hiroshima University, Department of Molecular and Internal Medicine, Division of Clinical Medical Science, Programs for Applied Biomedicine, Graduate School of Biomedical Sciences, Hiroshima (Japan); Ito, Katsuhide [Hiroshima University, Department of Radiology, Division of Medical Intelligence and Informatics, Programs for Applied Biomedicine, Graduate School of Biomedical Sciences, Hiroshima (Japan)

    2009-10-15

    The purpose of this study was to compare coronary 64-slice CT angiography (CTA) protocols, specifically prospective electrocardiograph (ECG)-triggered and retrospective ECG-gated CT acquisition performed using a tube voltage of 140 kV and 120 kV, regarding intracoronary stent imaging. Coronary artery stents (n=12) with artificial in-stent restenosis (50% luminal reduction, 40 HU) on a cardiac phantom were examined by CT at heart rates of 50-75 beats per minute (bpm). The subjective visibility of in-stent restenosis was evaluated with a three-point scale (1 clearly visible, 2 visible, and 3 not visible), and artificial lumen narrowing [(inner stent diameter - measured lumen diameter)/inner stent diameter], lumen attenuation increase ratio [(in-stent attenuation - coronary lumen attenuation)/coronary lumen attenuation], and signal-to-noise ratio of in-stent lumen were determined. The effective dose was estimated. The artificial lumen narrowing (mean 43%), the increase of lumen attenuation (mean 46%), and signal-to-noise ratio (mean 7.8) were not different between CT acquisitions (p=0.12-0.91). However, the visibility scores of in-stent restenosis were different (p<0.05) between ECG-gated CTA techniques: (a) 140-kV prospective (effective dose 4.6 mSv), 1.6; (b) 120-kV prospective (3.3 mSv), 1.8; (c) 140-kV retrospective (16.4-18.8 mSv), 1.9; and (d) 120-kV retrospective (11.0-13.4 mSv), 1.9. Thus, 140-kV prospective ECG-triggered CTA improves coronary in-stent restenosis visibility at a lower radiation dose compared with retrospective ECG-gated CTA. (orig.)

  6. Qualitative and Quantitative Status and International Visibility of Iranian Journals Indexed in Journal Citation Reports

    Directory of Open Access Journals (Sweden)

    Mohammadamin Erfanmanesh

    2016-12-01

    Full Text Available Objectives: The present study aims to investigate the international status and visibility of Iranian journals which have been indexed in Journal Citation Reports (JCR. Accordingly, the number of international papers, citations and editorial board members of each journal was studied. Moreover, various measures were utilized to compare the quality of Iranian journals with their international counterparts. Method: Current paper applied scientometric research method. A total of 16471 papers which published in 38 Iranian journals and indexed by the JCR 2013 were selected as the population of the study. Web of Science (WoS, JCR and journals’ website were used for data gathering. Results: Results of the study revealed that foreign researchers have published 34.8% of papers published in Iranian ISI journals. Moreover, only 30.6% of citations to Iranian ISI journals have been received from foreign papers or Iranian internationally collaborative papers. The results showed that Iranian researchers accounted for 66.4% of editorial board member of all studied journals, while foreign researchers only occupied 33.6% of the editorial board positions. Based on the findings, only two Iranian journals have impact factors above the median of the journals in the disciplinary category areas in which they are classified in JCR. Furthermore, only 8 Iranian journals have ever been placed in the 1st and 2nd quartile of journals of the same field in the JCR. Findings also showed that 36 out of the 38 Iranian journals have mostly cited by journals with higher median impact factors than cited journals. Conclusion: The findings indicate that the share of international papers, citations and editorial board memberships is low in Iranian ISI journals. Moreover, Iranian journals’ impact factor was below of those of the leading journals.

  7. Visibility of fiducial markers used for image-guided radiation therapy on optical coherence tomography for registration with CT: An esophageal phantom study.

    Science.gov (United States)

    Jelvehgaran, Pouya; Alderliesten, Tanja; Weda, Jelmer J A; de Bruin, Martijn; Faber, Dirk J; Hulshof, Maarten C C M; van Leeuwen, Ton G; van Herk, Marcel; de Boer, Johannes F

    2017-12-01

    Optical coherence tomography (OCT) is of interest to visualize microscopic esophageal tumor extensions to improve tumor delineation for radiation therapy (RT) planning. Fiducial marker placement is a common method to ensure target localization during planning and treatment. Visualization of these fiducial markers on OCT permits integrating OCT and computed tomography (CT) images used for RT planning via image registration. We studied the visibility of 13 (eight types) commercially available solid and liquid fiducial markers in OCT images at different depths using dedicated esophageal phantoms and evaluated marker placement depth in clinical practice. We designed and fabricated dedicated esophageal phantoms, in which three layers mimic the anatomical wall structures of a healthy human esophagus. We successfully implanted 13 commercially available fiducial markers that varied in diameter and material property at depths between 0.5 and 3.0 mm. The resulting esophageal phantoms were imaged with OCT, and marker visibility was assessed qualitatively and quantitatively using the contrast-to-background-noise ratio (CNR). The CNR was defined as the difference between the mean intensity of the fiducial markers and the mean intensity of the background divided by the standard deviation of the background intensity. To determine whether, in current clinical practice, the implanted fiducial markers are within the OCT visualization range (up to 3.0 mm depth), we retrospectively measured the distance of 19 fiducial markers to the esophageal lumen on CT scans of 16 esophageal cancer patients. In the esophageal phantoms, all the included fiducial markers were visible on OCT at all investigated depths. Solid fiducial markers were better visible on OCT than liquid fiducial markers with a 1.74-fold higher CNR. Although fiducial marker identification per type and size was slightly easier for superficially implanted fiducial markers, we observed no difference in the ability of OCT to

  8. Machine learning-based quantitative texture analysis of CT images of small renal masses: Differentiation of angiomyolipoma without visible fat from renal cell carcinoma.

    Science.gov (United States)

    Feng, Zhichao; Rong, Pengfei; Cao, Peng; Zhou, Qingyu; Zhu, Wenwei; Yan, Zhimin; Liu, Qianyun; Wang, Wei

    2018-04-01

    To evaluate the diagnostic performance of machine-learning based quantitative texture analysis of CT images to differentiate small (≤ 4 cm) angiomyolipoma without visible fat (AMLwvf) from renal cell carcinoma (RCC). This single-institutional retrospective study included 58 patients with pathologically proven small renal mass (17 in AMLwvf and 41 in RCC groups). Texture features were extracted from the largest possible tumorous regions of interest (ROIs) by manual segmentation in preoperative three-phase CT images. Interobserver reliability and the Mann-Whitney U test were applied to select features preliminarily. Then support vector machine with recursive feature elimination (SVM-RFE) and synthetic minority oversampling technique (SMOTE) were adopted to establish discriminative classifiers, and the performance of classifiers was assessed. Of the 42 extracted features, 16 candidate features showed significant intergroup differences (P Machine learning analysis of CT texture features can facilitate the accurate differentiation of small AMLwvf from RCC. • Although conventional CT is useful for diagnosis of SRMs, it has limitations. • Machine-learning based CT texture analysis facilitate differentiation of small AMLwvf from RCC. • The highest accuracy of SVM-RFE+SMOTE classifier reached 93.9 %. • Texture analysis combined with machine-learning methods might spare unnecessary surgery for AMLwvf.

  9. Cone-Beam CT Localization of Internal Target Volumes for Stereotactic Body Radiotherapy of Lung Lesions

    International Nuclear Information System (INIS)

    Wang Zhiheng; Wu, Q. Jackie; Marks, Lawrence B.; Larrier, Nicole; Yin Fangfang

    2007-01-01

    Purpose: In this study, we investigate a technique of matching internal target volumes (ITVs) in four-dimensional (4D) simulation computed tomography (CT) to the composite target volume in free-breathing on-board cone-beam (CB) CT. The technique is illustrated by using both phantom and patient cases. Methods and Materials: A dynamic phantom with a target ball simulating respiratory motion with various amplitude and cycle times was used to verify localization accuracy. The dynamic phantom was scanned using simulation CT with a phase-based retrospective sorting technique. The ITV was then determined based on 10 sets of sorted images. The size and epicenter of the ITV identified from 4D simulation CT images and the composite target volume identified from on-board CBCT images were compared to assess localization accuracy. Similarly, for two clinical cases of patients with lung cancer, ITVs defined from 4D simulation CT images and CBCT images were compared. Results: For the phantom, localization accuracy between the ITV in 4D simulation CT and the composite target volume in CBCT was within 1 mm, and ITV was within 8.7%. For patient cases, ITVs on simulation CT and CBCT were within 8.0%. Conclusion: This study shows that CBCT is a useful tool to localize ITV for targets affected by respiratory motion. Verification of the ITV from 4D simulation CT using on-board free-breathing CBCT is feasible for the target localization of lung tumors

  10. Usefulness of CT angiography after metallic stent implantation of the internal carotid artery

    International Nuclear Information System (INIS)

    Yoon, Man Won; Kim, Hyeon Chul; Kim, Jae Kyu; Seo, Jeong Jin; Jeong, Gwang Woo; Kang, Heoung Keun

    1999-01-01

    To evaluate the usefulness of CT angiography in patients with implantation of metallic stent for stenosed internal carotid artery. Seven patients with atherosclerotic stenosis of the internal carotid artery underwent metallic stent implantation. All were male and their ages ranged from 36 to 69 years. A total of seven stents were placed in the internal carotid artery in five patients and in the carotid bifurcation in two. Spiral CT scans were obtained and CT angiographic images were reconstructed using MPR or curved MPR techniques at a workstation. The interval between CT and conventional angiography did not exceed six days except in one patient, in whom it was 61days. CT and conventional angiography were compared for stent position with respect to the carotid bifurcation, stent deformation, intraluminal filling defect, and luminal caliber and outflow. Luminal patency of the implanted stent was measured according to NASCET(North American Symptomatic Carotid Endarterectomy Trial) criteria, and statistically processed (p>.05). The presence or absence of intrastent thrombus and vascular wall calcification was determined using axial source images. In all patients, CT angiographic findings matched those obtained by conventional angiography. Complications such as migration or deformation of an implanted stent, intraluminal filling defect, change of luminal caliber or outflow of implanted stent were not observed in any patient. In two studies in which Wilcoxon signed rank test was used, degree of stent expansion correlated closely(p=0.237). Axial source images showed that in no patient was an intrastent thrombus present, though in five, vascular wall calcification of internal carotid arteries outside the stent was noted. CT angiography is useful for the assessment of positional change, occlusion, and luminal patency of a stent-implanted internal carotid artery

  11. Lack of Correlation Between External Fiducial Positions and Internal Tumor Positions During Breath-Hold CT

    International Nuclear Information System (INIS)

    Hunjan, Sandeep; Starkschall, George; Prado, Karl; Dong Lei; Balter, Peter

    2010-01-01

    Purpose: For thoracic tumors, if four-dimensional computed tomography (4DCT) is unavailable, the internal margin can be estimated by use of breath-hold (BH) CT scans acquired at end inspiration (EI) and end expiration (EE). By use of external surrogates for tumor position, BH accuracy is estimated by minimizing the difference between respiratory extrema BH and mean equivalent-phase free breathing (FB) positions. We tested the assumption that an external surrogate for BH accuracy correlates with internal tumor positional accuracy during BH CT. Methods and Materials: In 16 lung cancer patients, 4DCT images, as well as BH CT images at EI and EE, were acquired. Absolute differences between BH and mean equivalent-phase (FB) positions were calculated for both external fiducials and gross tumor volume (GTV) centroids as metrics of external and internal BH accuracy, respectively, and the results were correlated. Results: At EI, the absolute difference between mean FB and BH fiducial displacement correlated poorly with the absolute difference between FB and BH GTV centroid positions on CT images (R 2 = 0.11). Similarly, at EE, the absolute difference between mean FB and BH fiducial displacements correlated poorly with the absolute difference between FB and BH GTV centroid positions on CT images (R 2 = 0.18). Conclusions: External surrogates for tumor position are not an accurate metric of BH accuracy for lung cancer patients. This implies that care should be taken when using such an approach because an incorrect internal margin could be generated.

  12. The use of CT density changes at internal tissue interfaces to correlate internal organ motion with an external surrogate

    Energy Technology Data Exchange (ETDEWEB)

    Gaede, Stewart; Yu, Edward; Van Dyk, Jake; Battista, Jerry [Radiation Oncology Program, London Regional Cancer Program, London, Ontario (Canada); Carnes, Gregory; Lee, Ting-Yim [Department of Medical Biophysics, University of Western Ontario, London, Ontario (Canada)

    2009-01-21

    The purpose of this paper is to describe a non-invasive method to monitor the motion of internal organs affected by respiration without using external markers or spirometry, to test the correlation with external markers, and to calculate any time shift between the datasets. Ten lung cancer patients were CT scanned with a GE LightSpeed Plus 4-Slice CT scanner operating in a cine mode. We retrospectively reconstructed the raw CT data to obtain consecutive 0.5 s reconstructions at 0.1 s intervals to increase image sampling. We defined regions of interest containing tissue interfaces, including tumour/lung interfaces that move due to breathing on multiple axial slices and measured the mean CT number versus respiratory phase. Tumour motion was directly correlated with external marker motion, acquired simultaneously, using the sample coefficient of determination, r{sup 2}. Only three of the ten patients showed correlation higher than r{sup 2} = 0.80 between tumour motion and external marker position. However, after taking into account time shifts (ranging between 0 s and 0.4 s) between the two data sets, all ten patients showed correlation better than r{sup 2} = 0.8. This non-invasive method for monitoring the motion of internal organs is an effective tool that can assess the use of external markers for 4D-CT imaging and respiratory-gated radiotherapy on a patient-specific basis.

  13. Multidetector-Row CT Findings of an Internal Supravesical Hernia: A Case Report

    International Nuclear Information System (INIS)

    Kim, Sang Won; Shin, Hyeong Cheol; Kim, Hyung Hwan; Kim, Young Tong; Kim, Il Young; Kang, Kil Ho

    2010-01-01

    A supravesical hernia occurs in the supravesical fossa and is either classified as an external or internal supravesical hernia. Most patients with internal supravesical hernias present with small bowel obstruction. Internal supravesical hernias are less common than external supravesical hernia. To date, there are few reports describing the radiological findings of supravesical hernias. To our knowledge, this is the first reported multidetector row CT (MDCT) depiction of this type of hernia. We report here on the MDCT findings of a patient with an internal supravesical hernia presenting with small bowel obstruction

  14. Cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS flat panel detector: visibility of simulated microcalcifications.

    Science.gov (United States)

    Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen; Wang, Tianpeng; Shaw, Chris C

    2013-10-01

    To measure and investigate the improvement of microcalcification (MC) visibility in cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS/CsI flat panel detector (Dexela 2923, Perkin Elmer). Aluminum wires and calcium carbonate grains of various sizes were embedded in a paraffin cylinder to simulate imaging of calcifications in a breast. Phantoms were imaged with a benchtop experimental cone beam CT system at various exposure levels. In addition to the Dexela detector, a high pitch (50 μm), thin (150 μm) scintillator CMOS/CsI flat panel detector (C7921CA-09, Hamamatsu Corporation, Hamamatsu City, Japan) and a widely used low pitch (194 μm), thick (600 μm) scintillator aSi/CsI flat panel detector (PaxScan 4030CB, Varian Medical Systems) were also used in scanning for comparison. The images were independently reviewed by six readers (imaging physicists). The MC visibility was quantified as the fraction of visible MCs and measured as a function of the estimated mean glandular dose (MGD) level for various MC sizes and detectors. The modulation transfer functions (MTFs) and detective quantum efficiencies (DQEs) were also measured and compared for the three detectors used. The authors have demonstrated that the use of a high pitch (75 μm) CMOS detector coupled with a thick (500 μm) CsI scintillator helped make the smaller 150-160, 160-180, and 180-200 μm MC groups more visible at MGDs up to 10.8, 9, and 10.8 mGy, respectively. It also made the larger 200-212 and 212-224 μm MC groups more visible at MGDs up to 7.2 mGy. No performance improvement was observed for 224-250 μm or larger size groups. With the higher spatial resolution of the Dexela detector based system, the apparent dimensions and shapes of MCs were more accurately rendered. The results show that with the aforementioned detector, a 73% visibility could be achieved in imaging 160-180 μm MCs as compared to 28% visibility achieved by the low pitch (194 μm) aSi/CsI flat

  15. TU-E-217BCD-06: Cone Beam Breast CT with a High Resolution Flat Panel Detector-Improvement of Calcification Visibility.

    Science.gov (United States)

    Shen, Y; Zhong, Y; Lai, C; Wang, T; Shaw, C

    2012-06-01

    To investigate the advantage of a high resolution flat panel detector for improving the visibility of microcalcifications (MCs) in cone beam breast CT Methods: A paraffin cylinder was used to simulate a 100% adipose breast. Calcium carbonate grains, ranging from 125-140 μm to 224 - 250 μm in size, were used to simulate the MCs. Groups of 25 same size MCs were embedded at the phantom center. The phantom was scanned with a bench-top CBCT system at various exposure levels. A 75μm pitch flat panel detector (Dexela 2923, Perkin Elmer) with 500μm thick CsI scintillator plate was used as the high resolution detector. A 194 μm pitch detector (Paxscan 4030CB, Varian Medical Systems) was used for reference. 300 projection images were acquired over 360° and reconstructed. The images were reviewed by 6 readers. The MC visibility was quantified as the fraction of visible MCs and averaged for comparison. The visibility was plotted as a function of the estimated dose level for various MC sizes and detectors. The MTFs and DQEs were measured and compared. For imaging small (200 μm and smaller) MCs, the visibility achieved with the 75μm pitch detector was found to be significantly higher than those achieved with the 194μm pitch detector. For imaging larger MCs, there was little advantage in using the 75μm pitch detector. Using the 75μm pitch detector, MCs as small as 180 μm could be imaged to achieve a visibility of 78% with an isocenter tissue dose of ∼20 mGys versus 62% achieved with the 194 μm pitch detector at the same dose level. It was found that a high pitch flat panel detector had the advantages of extending its imaging capability to higher frequencies thus helping improve the visibility when used to image small MCs. This work was supported in part by grants CA104759, CA13852 and CA124585 from NIH-NCI, a grant EB00117 from NIH-NIBIB, and a subcontract from NIST-ATP. © 2012 American Association of Physicists in Medicine.

  16. Machine learning-based quantitative texture analysis of CT images of small renal masses. Differentiation of angiomyolipoma without visible fat from renal cell carcinoma

    International Nuclear Information System (INIS)

    Feng, Zhichao; Rong, Pengfei; Zhou, Qingyu; Zhu, Wenwei; Yan, Zhimin; Liu, Qianyun; Wang, Wei; Cao, Peng

    2018-01-01

    To evaluate the diagnostic performance of machine-learning based quantitative texture analysis of CT images to differentiate small (≤ 4 cm) angiomyolipoma without visible fat (AMLwvf) from renal cell carcinoma (RCC). This single-institutional retrospective study included 58 patients with pathologically proven small renal mass (17 in AMLwvf and 41 in RCC groups). Texture features were extracted from the largest possible tumorous regions of interest (ROIs) by manual segmentation in preoperative three-phase CT images. Interobserver reliability and the Mann-Whitney U test were applied to select features preliminarily. Then support vector machine with recursive feature elimination (SVM-RFE) and synthetic minority oversampling technique (SMOTE) were adopted to establish discriminative classifiers, and the performance of classifiers was assessed. Of the 42 extracted features, 16 candidate features showed significant intergroup differences (P < 0.05) and had good interobserver agreement. An optimal feature subset including 11 features was further selected by the SVM-RFE method. The SVM-RFE+SMOTE classifier achieved the best performance in discriminating between small AMLwvf and RCC, with the highest accuracy, sensitivity, specificity and AUC of 93.9 %, 87.8 %, 100 % and 0.955, respectively. Machine learning analysis of CT texture features can facilitate the accurate differentiation of small AMLwvf from RCC. (orig.)

  17. CT features of vasculitides based on the 2012 international chapel hill consensus conference revised classification

    International Nuclear Information System (INIS)

    Hur, Jee Hye; Chun, Eun Ju; Kim, Hae Young; Kim, Jeong Jae; Lee, Kyung Won; Kwang, Hyon Joo; Yoo, Jin Young

    2017-01-01

    Vasculitis, characterized by inflammation of vessel walls, is comprised of heterogeneous clinicopathological entities, and thus poses a diagnostic challenge. The most widely used approach for classifying vasculitides is based on the International Chapel Hill Consensus Conference (CHCC) nomenclature system. Based on the recently revised CHCC 2012, we propose computed tomography (CT) features of vasculitides and a differential diagnosis based on location and morphological characteristics. Finally, vasculitis mimics should be differentiated, because erroneous application of immunosuppressive drugs on vasculitis mimics may be ineffective, even deteriorating. This article presents the utility of CT in the diagnosis and differential diagnosis of vasculitides

  18. CT features of vasculitides based on the 2012 international chapel hill consensus conference revised classification

    Energy Technology Data Exchange (ETDEWEB)

    Hur, Jee Hye; Chun, Eun Ju; Kim, Hae Young; Kim, Jeong Jae; Lee, Kyung Won [Dept. of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Kwang, Hyon Joo [Dept. of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Yoo, Jin Young [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2017-09-15

    Vasculitis, characterized by inflammation of vessel walls, is comprised of heterogeneous clinicopathological entities, and thus poses a diagnostic challenge. The most widely used approach for classifying vasculitides is based on the International Chapel Hill Consensus Conference (CHCC) nomenclature system. Based on the recently revised CHCC 2012, we propose computed tomography (CT) features of vasculitides and a differential diagnosis based on location and morphological characteristics. Finally, vasculitis mimics should be differentiated, because erroneous application of immunosuppressive drugs on vasculitis mimics may be ineffective, even deteriorating. This article presents the utility of CT in the diagnosis and differential diagnosis of vasculitides.

  19. Studies on the consistency of internally taken contrast medium for pancreas CT

    Energy Technology Data Exchange (ETDEWEB)

    Matsushima, Kishio; Mimura, Seiichi; Tahara, Seiji; Kitayama, Takuichi; Inamura, Keiji; Mikami, Yasutaka; Hashimoto, Keiji; Hiraki, Yoshio; Aono, Kaname

    1985-02-01

    A problem of Pancreatic CT scanning is the discrimination between the pancreas and the adjacent gastrointestinal tract. Generally we administer a dilution of gastrografin internally to make the discrimination. The degree of dilution has been decided by experience at each hospital. When the consistency of the contrast medium is low in density, an enhancement effect cannot be expected, but when the consistency is high, artifacts appear. We have experimented on the degree of the dilution and CT-No to decide the optimum consistency of gastrografin for the diagnosis of pancreatic disease. Statistical analysis of the results show the optimum dilution of gastrografin to be 1.5%.

  20. Dissecting aneurysm of the cervical internal carotid artery. Cervical CT scan findings and treatment - case report

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Yoshihiro; Itoyama, Youichi; Fukumura, Akinobu; Matsukado, Yasuhiko; Kodama, Takafumi

    1987-06-01

    On lifting a heavy case, a 51-year-old male experienced a sudden onset of headache with giddiness and clouded vision. A week later, vertigo and right hand numbness were added to his symptoms. The next day anisocoria (right > left) and dilation of the left retinal veins were noted. Cranial computed tomography (CT) scan appeared normal and there were no other remarkable neurological findings. The patient was treated conservatively for cerebral infarction, however, the headache worsened and diplopia occurred. Neurological examination on admission revealed nothing unusual except for left Horner's syndrome. Physical examination showed a palpable sausage-like painless tumor on the left side of the neck. Angiography showed a narrowing of the internal carotid artery in the cervical region with a small dissecting aneurysm at the C3 level. Cervical CT scan at the upper C3 level showed a low density lunar defect in the high density section of the enlarged left internal carotid artery. The patient was operated on by superficial temporal artery-middle cerebral artery anastomosis to increase the intracranial blood flow. Postoperatively the symptoms were quickly relieved. Angiography 1 month later showed less narrowing of the carotid artery, though the dissecting aneurysm still remained. Postoperative cervical CT scan showed the left internal carotid artery to be of normal size. The patient returned to his work in normal condition 2 months later. It is emphasized that cervical CT scan may be useful in the diagnosis of this unusual type of cervical dissecting aneurysm.

  1. Dissecting aneurysm of the cervical internal carotid artery. Cervical CT scan findings and treatment - case report

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Yoshihiro; Itoyama, Youichi; Fukumura, Akinobu; Matsukado, Yasuhiko; Kodama, Takafumi

    1987-06-01

    On lifting a heavy case, a 51-year-old male experienced a sudden onset of headache with giddiness and clouded vision. A week later, vertigo and right hand numbness were added to his symptoms. The next day anisocoria (right > left) and dilation of the left retinal veins were noted. Cranial computed tomography (CT) scan appeared normal and there were no other remarkable neurological findings. The patient was treated conservatively for cerebral infarction, however, the headache worsened and diplopia occurred. Neurological examination on admission revealed nothing unusual except for left Horner's syndrome. Physical examination showed a palpable sausage-like painless tumor on the left side of the neck. Angiography showed a narrowing of the internal carotid artery in the cervical region with a small dissecting aneurysm at the C3 level. Cervical CT scan at the upper C3 level showed a low density lunar defect in the high density section of the enlarged left internal carotid artery. The patient was operated on by superficial temporal artery-middle cerebral artery anastomosis to increase the intracranial blood flow. Postoperatively the symptoms were quickly relieved. Angiography 1 month later showed less narrowing of the carotid artery, though the dissecting aneurysm still remained. Postoperative cervical CT scan showed the left internal carotid artery to be of normal size. The patient returned to his work in normal condition 2 months later. It is emphasized that cervical CT scan may be useful in the diagnosis of this unusual type of cervical dissecting aneurysm.

  2. A Strategy to Increase the International Visibility and Participation of a State University

    Science.gov (United States)

    Lucas, Stephen R.; Miles, Benton E.

    2007-01-01

    This paper presents a strategy for expanding a university's international participation. An effort to correct international exchange imbalances evolved into a unique international program and partnership with Walt Disney World.

  3. Prospective evaluation of MR overlay on real-time fluoroscopy for percutaneous extremity biopsies of bone lesions visible on MRI but not on CT in children in the interventional radiology suite

    Energy Technology Data Exchange (ETDEWEB)

    Shellikeri, Sphoorti; Vatsky, Seth; Srinivasan, Abhay; Krishnamurthy, Ganesh; Zhu, Xiaowei; Keller, Marc S.; Cahill, Anne Marie [Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); Setser, Randolph M. [Siemens Medical Solutions USA, Inc., Hoffman Estates, IL (United States)

    2018-02-15

    Magnetic resonance imaging (MRI) often provides better visualization of bone marrow abnormalities than computed tomography (CT) or fluoroscopy, but bone biopsies are usually performed using conventional CT or, more recently, C-arm CT guidance. Biopsies of bone lesions solely visible on MRI are often challenging to localize and require the operator to review the MRI on a separate console to correlate with MRI anatomical landmarks during the biopsy. The MR overlay technique facilitates such biopsies in the angiographic suite by allowing the pre-procedural 3-D MRI to be overlaid on intraprocedural 2-D fluoroscopy. This study describes our initial experience with the MR overlay technique in the angiography suite during pediatric percutaneous extremity bone biopsies of lesions visible on MRI but not on CT or fluoroscopy and demonstrates its utility in relevant clinical cases. (orig.)

  4. Prospective evaluation of MR overlay on real-time fluoroscopy for percutaneous extremity biopsies of bone lesions visible on MRI but not on CT in children in the interventional radiology suite

    International Nuclear Information System (INIS)

    Shellikeri, Sphoorti; Vatsky, Seth; Srinivasan, Abhay; Krishnamurthy, Ganesh; Zhu, Xiaowei; Keller, Marc S.; Cahill, Anne Marie; Setser, Randolph M.

    2018-01-01

    Magnetic resonance imaging (MRI) often provides better visualization of bone marrow abnormalities than computed tomography (CT) or fluoroscopy, but bone biopsies are usually performed using conventional CT or, more recently, C-arm CT guidance. Biopsies of bone lesions solely visible on MRI are often challenging to localize and require the operator to review the MRI on a separate console to correlate with MRI anatomical landmarks during the biopsy. The MR overlay technique facilitates such biopsies in the angiographic suite by allowing the pre-procedural 3-D MRI to be overlaid on intraprocedural 2-D fluoroscopy. This study describes our initial experience with the MR overlay technique in the angiography suite during pediatric percutaneous extremity bone biopsies of lesions visible on MRI but not on CT or fluoroscopy and demonstrates its utility in relevant clinical cases. (orig.)

  5. Incidental internal carotid artery calcifications on temporal bone CT in children

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Bernadette; Jones, Blaise [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Blackham, Aaron [University of Cincinnati College of Medicine, Cincinnati, OH (United States)

    2007-02-15

    Incidental internal carotid artery (ICA) calcifications are occasionally noted on CT images of the brain and temporal bone. In adults, incidental calcifications have been correlated with increased incidence of hypercholesterolemia, cardiac disease, diabetes and carotid stenosis. To determine the incidence of incidental calcifications of the carotid siphon on temporal bone CT in children. We retrospectively reviewed 24 months of consecutive temporal bone CT examinations in children aged 18 years and younger. CT examinations on 663 patients were reviewed and the presence or absence of ICA calcifications was ranked as absent, questionable or definitive. In patients in whom definitive calcifications were identified, hospital charts were reviewed for evidence of diabetes mellitus, hypercholesterolemia, hypertriglyceridemia, hyperlipidemia and chronic renal disease as potential causes of early atherosclerosis. Of the 663 patients, 25% had definitive calcifications within the wall of the ICA: 6% of children younger than 2 years and 28% of children 12-19 years of age. Incidentally noted ICA calcifications are a common finding on temporal bone CT in children, most likely a physiologic response to turbulent flow at natural bends in the artery rather than secondary to underlying disease predisposing to early atherosclerotic calcification. (orig.)

  6. Thrombophlebitis of the internal jugular vein (Lemierre syndrome) - Clinical and CT findings

    International Nuclear Information System (INIS)

    Kim, Bo Yeon; Yoon, Dae Young; Lim, Kyoung Ja; Seo, Young Lan; Yun, Eun Joo; Choi, Chul Soon; Bae, Sang Hoon; Kim, Hyeong Chul; Kim, Eun Soo; Baek, Sora

    2013-01-01

    Background: Thrombophlebitis of the internal jugular vein (IJV) secondary to neck infection (so-called Lemierre syndrome) is a rare disease. Purpose: To evaluate the clinical and CT findings in patients with thrombophlebitis of the IJV. Material and Methods: The clinical and contrast-enhanced neck CT findings were retrospective analyzed in 10 patients (eight men, two women; mean age, 62.9±8.3 years) with thrombophlebitis of the IJV. Results: Five patients (50%) had complications, including pneumonia (n = 3), neck abscess (n = 1), and thrombophlebitis of cerebral venous sinus (n = 1). All patients, except two who were lost to follow-up, had improved after antibiotics and anticoagulation therapy. Nine (90%) patients had underlying infectious processes in the neck. Contrast-enhanced neck CT of 12 IJVs (five right, three left, and two bilateral) affected by thrombophlebitis demonstrated > 5 cm in length (n = 8, 67%), ovoid shape (n = 7, 58%), complete occlusion of the lumen (n = 10, 83%), circumferential (n = 11, 92%), smooth (n = 8, 67%), and thick (=4 mm) (n = 8, 67%) rim enhancement, and adjacent soft tissue swelling (n = 11, 92%). Conclusion: Contrast-enhanced CT is useful in the diagnosis of thrombophlebitis of the IJV; characteristic CT findings of this unusual entity may be the main clue to the correct diagnosis

  7. Incidental internal carotid artery calcifications on temporal bone CT in children

    International Nuclear Information System (INIS)

    Koch, Bernadette; Jones, Blaise; Blackham, Aaron

    2007-01-01

    Incidental internal carotid artery (ICA) calcifications are occasionally noted on CT images of the brain and temporal bone. In adults, incidental calcifications have been correlated with increased incidence of hypercholesterolemia, cardiac disease, diabetes and carotid stenosis. To determine the incidence of incidental calcifications of the carotid siphon on temporal bone CT in children. We retrospectively reviewed 24 months of consecutive temporal bone CT examinations in children aged 18 years and younger. CT examinations on 663 patients were reviewed and the presence or absence of ICA calcifications was ranked as absent, questionable or definitive. In patients in whom definitive calcifications were identified, hospital charts were reviewed for evidence of diabetes mellitus, hypercholesterolemia, hypertriglyceridemia, hyperlipidemia and chronic renal disease as potential causes of early atherosclerosis. Of the 663 patients, 25% had definitive calcifications within the wall of the ICA: 6% of children younger than 2 years and 28% of children 12-19 years of age. Incidentally noted ICA calcifications are a common finding on temporal bone CT in children, most likely a physiologic response to turbulent flow at natural bends in the artery rather than secondary to underlying disease predisposing to early atherosclerotic calcification. (orig.)

  8. Comparison of image quality and visibility of normal and abnormal findings at submillisievert chest CT using filtered back projection, iterative model reconstruction (IMR) and iDose{sup 4}™

    Energy Technology Data Exchange (ETDEWEB)

    Laqmani, Azien, E-mail: a.laqmani@uke.de [Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg (Germany); Avanesov, Maxim; Butscheidt, Sebastian; Kurfürst, Maximilian [Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg (Germany); Sehner, Susanne [Department of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg (Germany); Schmidt-Holtz, Jakob; Derlin, Thorsten; Behzadi, Cyrus [Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg (Germany); Nagel, Hans D. [Science & Technology for Radiology, Fritz-Reuter-Weg 5f, 21244 Buchholz, Germany, (Germany); Adam, Gerhard; Regier, Marc [Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg (Germany)

    2016-11-15

    Objective: To compare both image quality and visibility of normal and abnormal findings at submillisievert chest CT (smSv-CT) using filtered back projection (FBP) and the two different iterative reconstruction (IR) techniques iterative model reconstruction (IMR) and iDose{sup 4}™. Materials and methods: This institutional review board approved study was based on retrospective interpretation of clinically indicated acquired data. The requirement to obtain informed consent was waived. 81 patients with suspected pneumonia underwent smSv-CT (Brilliance iCT, Philips Healthcare; mean effective dose: 0.86 ± 0.2 mSv). Data were reconstructed using FBP and two different IR techniques iDose{sup 4}™ and IMR (Philips Healthcare) at various iteration levels. Objective image noise (OIN) was measured. Two experienced readers independently assessed all images for image noise, image appearance and visibility of normal anatomic and abnormal findings. A random intercept model was used for statistical analysis. Results: Compared to FBP and iDose{sup 4}™, IMR reduced OIN up to 88% and 72%, respectively (p < 0.001). A mild blotchy image appearance was seen in IMR images, affecting diagnostic confidence. iDose{sup 4}™ images provided satisfactory to good image quality for visibility of normal and abnormal findings and were superior to FBP (p < 0.001). IMR images were significantly inferior for visibility of normal structures compared to iDose{sup 4}™, while being superior for visibility of abnormal findings except for reticular pattern (p < 0.001). Conclusion: IMR results for visibility of normal and abnormal lung findings are heterogeneous, indicating that IMR may not represent a priority technique for clinical routine. iDose{sup 4}™ represents a suitable method for evaluation of lung tissue at submillisievert chest CT.

  9. CT imaging of the internal human ear: Test of a high resolution scanner

    Energy Technology Data Exchange (ETDEWEB)

    Bettuzzi, M., E-mail: matteo.bettuzzi@unibo.it [Department of Physics, University of Bologna and National Institute of Nuclear Physics Section of Bologna (Italy); Brancaccio, R.; Morigi, M.P. [Department of Physics, University of Bologna and National Institute of Nuclear Physics Section of Bologna (Italy); Gallo, A. [Medicine Faculty, Magna Graecia University, Catanzaro and INFN Cosenza (Italy); Strolin, S.; Casali, F. [Department of Physics, University of Bologna and National Institute of Nuclear Physics Section of Bologna (Italy); Lamanna, Ernesto [Medicine Faculty, Magna Graecia University, Catanzaro and INFN Cosenza (Italy); Ariu, Marilu [CEFLA Dental Group, Imola (Italy)

    2011-08-21

    During the course of 2009, in the framework of a project supported by the National Institute of Nuclear Physics, a number of tests were carried out at the Department of Physics of the University of Bologna in order to achieve a good quality CT scan of the internal human ear. The work was carried out in collaboration with the local 'S. Orsola' Hospital in Bologna and a company (CEFLA) already involved in the production and commercialization of a CT scanner dedicated to dentistry. A laboratory scanner with a simple concept detector (CCD camera-lens-mirror-scintillator) was used to see to what extent it was possible to enhance the quality of a conventional CT scanner when examining the internal human ear. To test the system, some conventional measurements were made, such as the spatial resolution calculation with the MTF and dynamic range evaluation. Different scintillators were compared to select the most suitable for the purpose. With 0.5 mm thick structured cesium iodide and a field of view of 120x120 mm{sup 2}, a spatial resolution of 6.5l p/mm at 5% MTF was obtained. The CT of a pair of human head phantoms was performed at an energy of 120 kVp. The first phantom was a rough representation of the human head shape, with soft tissue made of coarse slabs of Lucite. Some inserts, like small aluminum cylinders and cubes, with 1 mm diameter drilled holes, were used to simulate the channels that one finds inside the human inner ear. The second phantom is a plastic PVC fused head with a real human cranium inside. The bones in the cranium are well conserved and the inner ear features, such as the cochlea and semicircular channels, are clearly detectable. After a number of CT tests we obtained good results as far as structural representation and channel detection are concerned. Some images of the 3D rendering of the CT volume are shown below. The doctors of the local hospital who followed our experimentation expressed their satisfaction. The CT was compared to a

  10. Improved Visibility of Metastatic Disease in the Liver During Intra-Arterial Therapy Using Delayed Arterial Phase Cone-Beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Schernthaner, Ruediger E., E-mail: ruediger.schernthaner@meduniwien.ac.at [Medical University of Vienna, Section of Cardiovascular and Interventional Radiology, Department of Biomedical Imaging and Image-guided Therapy (Austria); Haroun, Reham R., E-mail: rehamharoun1989@gmail.com; Duran, Rafael, E-mail: rafaelduran.md@gmail.com; Lee, Howard, E-mail: mail2howielee@gmail.com; Sahu, Sonia, E-mail: sonia.p.sahu@gmail.com; Sohn, Jae Ho, E-mail: sohn87@gmail.com; Chapiro, Julius, E-mail: j.chapiro@googlemail.com; Zhao, Yan, E-mail: yanzhao211@163.com; Gorodetski, Boris, E-mail: boris.gorodetski@charite.de; Fleckenstein, Florian, E-mail: florian.fleckenstein@charite.de; Smolka, Susanne, E-mail: susanne.smolka@charite.de [Yale University School of Medicine, Department of Radiology and Biomedical Imaging (United States); Radaelli, Alessandro, E-mail: Alessandro.Radaelli@philips.com; Bom, Imramsjah Martijn van der, E-mail: martijn.van.der.bom@philips.com [Philips Healthcare, Image-Guided Therapy Systems (Netherlands); Lin, MingDe, E-mail: ming.lin@philips.com; Geschwind, Jean Francois, E-mail: jeff.geschwind@yale.edu [Yale University School of Medicine, Department of Radiology and Biomedical Imaging (United States)

    2016-10-15

    PurposeTo compare the visibility of liver metastases on dual-phase cone-beam CT (DP-CBCT) and digital subtraction angiography (DSA), with reference to preinterventional contrast-enhanced magnetic resonance imaging (CE-MRI) of the liver.MethodsThis IRB-approved, retrospective study included 28 patients with neuroendocrine (NELM), colorectal (CRCLM), or sarcoma (SLM) liver metastases who underwent DP-CBCT during intra-arterial therapy (IAT) between 01/2010 and 10/2014. DP-CBCT was acquired after a single contrast agent injection in the tumor-feeding arteries at early and delayed arterial phases (EAP and DAP). The visibility of each lesion was graded by two radiologists in consensus on a three-rank scale (complete, partial, none) on DP-CBCT and DSA images using CE-MRI as reference.Results47 NELM, 43 CRCLM, and 16 SLM were included. On DSA 85.1, 44.1, and 37.5 % of NELM, CRCLM, and SLM, were at least partially depicted, respectively. EAP-CBCT yielded significantly higher sensitivities of 88.3 and 87.5 % for CRCLM and SLM, respectively (p < 0.01), but not for NELM (89.4 %; p = 1.0). On DAP-CBCT all NELM, CRCLM, and SLM were visible (p < 0.001). Complete depiction was achieved on DSA for 59.6, 16.3, and 18.8 % of NELM, CRCLM, and SLM, respectively. The complete depiction rate on EAP-CBCT was significantly higher for CRCLM (46.5 %; p < 0.001), lower for NELM (40.4 %; p = 0.592), and similar for SLM (25 %, p = 0.399). On DAP-CBCT however, the highest rates of complete depiction were found—NELM (97.8 %; p = 0.008), CRCLM (95.3 %; p = 0.008), and SLM (100 %; p < 0.001).ConclusionDAP-CBCT substantially improved the visibility of liver metastases during IAT. Future studies need to evaluate the clinical impact.

  11. CT and MR imaging of congenital abnormalities of the inner ear and internal auditory canal

    International Nuclear Information System (INIS)

    Casselman, Jan W.; Offeciers, Erwin F.; Foer, Bert de; Govaerts, Paul; Kuhweide, Rudy; Somers, Thomas

    2001-01-01

    The embryology of the inner ear must be known as many of the inner ear malformations present as a result of the arrest during the various stages of embryology. These malformations are described in this 'embryologic' perspective and specific names for certain malformations are no longer used. Both CT and MR can be used to look at inner ear malformations but often both techniques are complementary. However, CT is preferred when associated middle- or external ear malformations must be excluded. Magnetic resonance is preferred when subtle changes in the membranous labyrinth or abnormalities of the nerves in the internal auditory canal must be visualised. The CT and MR technique must however be adapted as more and more subtle congenital malformations can only be seen when the right technique is used. The heavily T2-weighted gradient-echo or fast spin-echo MR techniques are mandatory if malformations of the inner ear must be excluded. The purpose of this paper is to describe the techniques used to study these patients and to give an overview of the most frequent and important congenital malformations which can be found in the inner ear and internal auditory canal/cerebellopontine angle

  12. Counting Family: Making the Family of International Students Visible in Higher Education Policy and Practice

    Science.gov (United States)

    Doyle, Stephanie; Loveridge, Judith; Faamanatu-Eteuati, Niusila

    2016-01-01

    This article focuses on a significant group of postgraduate international students overlooked by institutions and policymakers, namely those with accompanying partners and children. The economic importance of international students to Australia, Canada, New Zealand, the United Kingdom, and the United States of America is highlighted. It is argued…

  13. Ligation of the internal maxillary artery for intractable epistaxis. 3D imaging of internal maxillary artery using helical CT scan

    International Nuclear Information System (INIS)

    Handa, Toru; Yazin, Koji; Hirakawa, Katsuhiro; Fukushima, Noriyuki; Takumida, Masaya; Hirata, Shitau; Iguchi, Tetsuhiko; Amano, Yoshiharu

    2001-01-01

    Sever posterior epistaxis is one of the serious clinical problems. Nasal bleeding usually occurs in the anterior septal region, where it can be seen easily and controlled with topical cautery or localized packing. When the bleeding occurs in the posterior nose, it becomes a more serious problem. Many methods have been used to control posterior epistaxis. Some of these are electrocautery, posterior nasal packing, vascular ligation and therapeutic percutaneous embolization. Between 1997 and 2000, nineteen patients were admitted to our hospital because of intractable epistaxis. There were 16 male and 3 female patients whose average age was 55 years. Ten of 19 patients were hypertensive, and none of these had undergoing treatment. Five of 19 patients received maxillary artery ligation. Clinical applications of 3D imaging of the internal maxillary artery using helical CT scan were done for 5 patients. These images were helpful for planning of ligation of the internal maxillary artery. (author)

  14. Ligation of the internal maxillary artery for intractable epistaxis. 3D imaging of internal maxillary artery using helical CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Handa, Toru [Akitsu Prefectual Hospital, Hiroshima (Japan); Yazin, Koji; Hirakawa, Katsuhiro; Fukushima, Noriyuki; Takumida, Masaya; Hirata, Shitau; Iguchi, Tetsuhiko; Amano, Yoshiharu

    2001-03-01

    Sever posterior epistaxis is one of the serious clinical problems. Nasal bleeding usually occurs in the anterior septal region, where it can be seen easily and controlled with topical cautery or localized packing. When the bleeding occurs in the posterior nose, it becomes a more serious problem. Many methods have been used to control posterior epistaxis. Some of these are electrocautery, posterior nasal packing, vascular ligation and therapeutic percutaneous embolization. Between 1997 and 2000, nineteen patients were admitted to our hospital because of intractable epistaxis. There were 16 male and 3 female patients whose average age was 55 years. Ten of 19 patients were hypertensive, and none of these had undergoing treatment. Five of 19 patients received maxillary artery ligation. Clinical applications of 3D imaging of the internal maxillary artery using helical CT scan were done for 5 patients. These images were helpful for planning of ligation of the internal maxillary artery. (author)

  15. Internal carotid arterial occlusion in computed tomography. Correlation of CT and angiographic findings

    Energy Technology Data Exchange (ETDEWEB)

    Harada, K.; Miura, T.; Nishikubo, Y.; Kawai, R.; Mitomo, M. (Osaka Univ. (Japan). Faculty of Medicine)

    1981-09-01

    The computed tomographic appearance of internal carotid arterial occlusion was reviewed in 33 patients. In 23 of them, who underwent 4-vessel study, the angiographic and CT findings were compared. Ten patients were disclosed to have watershed infarction by CT. Seven of them had watershed processes in the centrum semiovale which were considered to be terminal infarction. Patients who showed watershed infarction under CT revealed inadequate circle of Willis and well-developed cortical anastomosis under angiography. Unilaterally accentuated cerebral atrophy, which we have called asymmetrical atrophy in this paper, was noted in 10 patients. The findings of asymmetrical cerebral atrophy sometimes resemble the changes secondary to old infarction. However, the changes in the lateral ventricle caused by asymmetrical cerebral atrophy are somewhat different from those resulting from old infarction. The angiographic findings suggested that asymmetrical cerebral atrophy is, in addition to being associated with incomplete circle of Willis, also associated with local circulatory disturbances which further decrease the regional cerebral blood flow in the affected hemisphere.

  16. Coronary artery visibility in free-breathing young children with congenital heart disease on cardiac 64-slice CT: dual-source ECG-triggered sequential scan vs. single-source non-ECG-synchronized spiral scan

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Hyun Woo; Yang, Dong Hyun [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul (Korea, Republic of)

    2010-10-15

    The potential impact of dual-source ECG-triggered sequential CT scan on coronary artery visibility has not been evaluated in free-breathing young children. To compare coronary artery visibility in free-breathing young children with congenital heart disease on cardiac 64-slice CT between dual-source ECG-triggered sequential (DSET) scan and single-source non-ECG-synchronized spiral (SSNE) scan. In 93 young children, 108 cardiac 64-slice CT examinations were performed during free-breathing. Visibility of coronary arteries and side branches was compared between SSNE and DSET scans. Heart rates and trigger delays for DSET scan were recorded. Effective dose of each scan technique was calculated. Visual grades were significantly higher (P < 0.001 or =0.011) on DSET scan than on SSNE scan except for the distal left anterior descending artery. Coronary arteries were traceable in 79.3% on DSET scan and 54.3% on SSNE scan in the overlapped scan range (P < 0.0001), and 97.1% and 71.9% for the origins and proximal segments (P < 0.0001). Visibility of side branches was improved on DSET scan by a factor of 2.0. Heart rates and trigger delays for DSET scan were 131 {+-} 24 beats per min and 199 {+-} 44 ms, respectively. Effective doses of DSET and SSNE scans were 0.36 {+-} 0.12 mSv and 0.99 {+-} 0.23 mSv, respectively. DSET scan improves visibility of coronary arteries on cardiac 64-slice CT in free-breathing young children with congenital heart disease, compared with SSNE scan. (orig.)

  17. Evaluation of internal adaptation of dental adhesive restorations using micro-CT

    Directory of Open Access Journals (Sweden)

    Oh-Hyun Kwon

    2012-02-01

    Full Text Available Objectives The internal adaptation of composite restorations with or without resin modified glass ionomer cement (RMGIC was analyzed non-destructively using Microcomputed tomography (micro-CT. Materials and Methods Thirty intact human teeth were used. The specimens were divided into 3 groups. In the control group, the cavities were etched with 10% phosphoric acid for 15 sec. Composite resin was filled into the cavity without adhesive. In group 1, light cured glass ionomer cement (GIC, Fuji II LC, GC was applied as a base. The cavities were then etched, bonded, light cured and filled with composites. In group 2, the cavities were then etched, bonded, light cured and filled with composites without base application. They were immersed in a 25% silver nitrate solution. Micro-CT was performed before and after mechanical loading. One-way ANOVA with Duncan analysis was used to compare the internal adaptation between the groups before or after loading. A paired t-test was used to compare internal adaptation before and after mechanical loading. All statistical inferences were made within the 95% confidence interval. Results The silver nitrate solution successfully penetrated into the dentinal tubules from the pulp spaces, and infiltrated into the gap between restoration and pulpal floor. Group 2 showed a lower adaptation than the control group and group 1 (p < 0.05. There was no significant difference between the control group and group 1. For all groups, there was a significant difference between before and after mechanical loading (p < 0.05. Conclusions The internal adaptation before and after loading was better when composites were bonded to tooth using adhesive than composites based with RMGIC.

  18. New radiological examination for tumor in the internal auditory canal by combination of air CT cisternography and target imaging

    Energy Technology Data Exchange (ETDEWEB)

    Yagishita, A.; Shiga, I.; Kanzaki, H. (Keio Univ., Tokyo (Japan). School of Medicine)

    1982-07-01

    A 56-year-old man was admitted to the hospital because of progressive right hearing disturbance and tinnitus. An x-ray film of the skull demonstrated dilatation of the right internal auditory canal. Intravcnously enhanced CT didn't reveal any tumor in the right cerebellopontine angle. An intracanalicular tumor was demonstrated by air CT cisternography with target imaging, and confirmed by surgery. This method is useful for the radiological evaluation of the intracanalicular tumors.

  19. A new radiological examination for tumor in the internal auditory canal by combination of air CT cisternography and target imaging

    International Nuclear Information System (INIS)

    Yagishita, Akira; Shiga, Itsuo; Kanzaki, Hitoshi

    1982-01-01

    A 56-year-old man was admitted to the hospital because of progressive right hearing disturbance and tinnitus. An x-ray film of the skull demonstrated dilatation of the right internal auditory canal. Intravcnously enhanced CT didn't reveal any tumor in the right cerebellopontine angle. An intracanalicular tumor was demonstrated by air CT cisternography with target imaging, and confirmed by surgery. This method is useful for the radiological evaluation of the intracanalicular tumors. (author)

  20. New radiological examination for tumor in the internal auditory canal by combination of air CT cisternography and target imaging

    Energy Technology Data Exchange (ETDEWEB)

    Yagishita, A; Shiga, I; Kanzaki, H [Keio Univ., Tokyo (Japan). School of Medicine

    1982-07-01

    A 56-year-old man was admitted to the hospital because of progressive right hearing disturbance and tinnitus. An x-ray film of the skull demonstrated dilatation of the right internal auditory canal. Intravcnously enhanced CT didn't reveal any tumor in the right cerebellopontine angle. An intracanalicular tumor was demonstrated by air CT cisternography with target imaging, and confirmed by surgery. This method is useful for the radiological evaluation of the intracanalicular tumors.

  1. Carotid bifurcation calcium and correlation with percent stenosis of the internal carotid artery on CT angiography

    International Nuclear Information System (INIS)

    McKinney, Alexander M.; Casey, Sean O.; Teksam, Mehmet; Truwit, Charles L.; Kieffer, Stephen; Lucato, Leandro T.; Smith, Maurice

    2005-01-01

    The aim of this paper was to determine the correlation between calcium burden (expressed as a volume) and extent of stenosis of the origin of the internal carotid artery (ICA) by CT angiography (CTA). Previous studies have shown that calcification in the coronary arteries correlates with significant vessel stenosis, and severe calcification (measured by CT) in the carotid siphon correlates with significant (greater than 50% stenosis) as determined angiographically. Sixty-one patients (age range 50-85 years) underwent CT of the neck with intravenous administration of iodinated contrast for a variety of conditions. Images were obtained with a helical multidetector array CT scanner and reviewed on a three-dimensional workstation. A single observer manipulated window and level to segment calcified plaque from vascular enhancement in order to quantify vascular calcium volume (cc) in the region of the bifurcation of the common carotid artery/ICA origin, and to measure the extent of ICA stenosis near the origin. A total of 117 common carotid artery bifurcations were reviewed. A ''significant'' stenosis was defined arbitrarily as >40% (to detect lesions before they become hemodynamically significant) of luminal diameter on CTA using NASCET-like criteria. All ''significant'' stenoses (21 out of 117 carotid bifurcations) had measurable calcium. We found a relatively strong correlation between percent stenosis and the calcium volume (Pearson's r= 0.65, P<0.0001). We also found that there was an even stronger correlation between the square root of the calcium volume and the percent stenosis as measured by CTA (r= 0.77, P<0.0001). Calcium volumes of 0.01, 0.03, 0.06, 0.09 and 0.12 cc were used as thresholds to evaluate for a ''significant'' stenosis. A receiver operating characteristic (ROC) curve demonstrated that thresholds of 0.06 cc (sensitivity 88%, specificity 87%) and 0.03 cc (sensitivity 94%, specificity 76%) generated the best combinations of sensitivity and

  2. [International visibility and impact of the Spanish research on prison health (2002-2011)].

    Science.gov (United States)

    Ruíz-Pérez, R; Robinson-García, N

    2013-01-01

    This paper sets out to analyze the dissemination and impact of Spanish research published in international scientific journals on Prison Health over the last decade. Descriptive, longitudinal and retrospective analysis of scientific output. We used the Medline-Pubmed database as an information resource. We focus on the bibliometric aspects of journals, papers and authors using the indicators offered by the Web of Science, the Journal Citation Reports and the Essential Science Indicators. We identify the output of Spanish researchers, journals in which they are published, authors and main research fields. From 2002 to 2011, Spanish researchers published 159 papers, that is, nearly 2% of the world's share in Prison Health. The publication profile is mainly in international journals with an average impact on JCR. The Revista Española de Sanidad Penitenciaria is the most productive journal (9.09%), although its role is not prominent. Only two authors can be considered as medium-high productive authors with 10 papers in the study time period. The co-authors network shows a dense network with 14 authors along with minor fragmented networks. As regards citations, 6 papers have been cited 15 or more times and only two can be considered as highly cited. Three main research fronts have been identified: infectious diseases, drugs and psychiatric-psychological problems. The Spanish research production on Prison Health represents a similar share of the world output similar to that of other disciplines (1.9%), although slightly lower (General Medicine represents 3.05%; Public Health, 2.38%; Psychiatry, 2.29%; Toxicology, 2.46%). It seems likely that this share will increase as a result of the inclusion of its main journal in Medline along with an increasing number of researchers working on this discipline at an international level. However, inclusion has not yet led to integration into high-impact journals or a larger number of citations. The average Journal Impact Factor is

  3. Observer reliability of CT angiography in the assessment of acute ischaemic stroke: data from the Third International Stroke Trial

    Energy Technology Data Exchange (ETDEWEB)

    Mair, Grant; Farrall, Andrew J.; Sellar, Robin J.; Mollison, Daisy; Sakka, Eleni; Palmer, Jeb; Wardlaw, Joanna M. [University of Edinburgh, Western General Hospital, Division of Neuroimaging Sciences, Edinburgh (United Kingdom); Kummer, Ruediger von [Dresden University Stroke Centre, University Hospital, Department of Neuroradiology, Dresden (Germany); Adami, Alessandro [Sacro Cuore-Don Calabria Hospital, Stroke Center, Department of Neurology, Negrar (Italy); White, Philip M. [Stroke Research Group, Newcastle upon Tyne (United Kingdom); Adams, Matthew E. [National Hospital for Neurology and Neurosurgery, Department of Neuroradiology, London (United Kingdom); Yan, Bernard [Royal Melbourne Hospital, Neurovascular Research Group, Parkville (Australia); Demchuk, Andrew M. [Calgary Stroke Program, Department of Clinical Neurosciences, Calgary (Canada); Ramaswamy, Rajesh; Rodrigues, Mark A.; Samji, Karim; Baird, Andrew J. [Royal Infirmary of Edinburgh, Department of Radiology, Edinburgh (United Kingdom); Boyd, Elena V. [Northwick Park Hospital, Department of Radiology, Harrow (United Kingdom); Cohen, Geoff; Perry, David; Sandercock, Peter A.G. [University of Edinburgh, Western General Hospital, Division of Clinical Neurosciences, Edinburgh (United Kingdom); Lindley, Richard [University of Sydney, Westmead Hospital Clinical School and The George Institute for Global Health, Sydney (Australia); Collaboration: The IST-3 Collaborative Group

    2014-10-07

    CT angiography (CTA) is often used for assessing patients with acute ischaemic stroke. Only limited observer reliability data exist. We tested inter- and intra-observer reliability for the assessment of CTA in acute ischaemic stroke. We selected 15 cases from the Third International Stroke Trial (IST-3, ISRCTN25765518) with various degrees of arterial obstruction in different intracranial locations on CTA. To assess inter-observer reliability, seven members of the IST-3 expert image reading panel (>5 years experience reading CTA) and seven radiology trainees (<2 years experience) rated all 15 scans independently and blind to clinical data for: presence (versus absence) of any intracranial arterial abnormality (stenosis or occlusion), severity of arterial abnormality using relevant scales (IST-3 angiography score, Thrombolysis in Cerebral Infarction (TICI) score, Clot Burden Score), collateral supply and visibility of a perfusion defect on CTA source images (CTA-SI). Intra-observer reliability was assessed using independently repeated expert panel scan ratings. We assessed observer agreement with Krippendorff's-alpha (K-alpha). Among experienced observers, inter-observer agreement was substantial for the identification of any angiographic abnormality (K-alpha = 0.70) and with an angiography assessment scale (K-alpha = 0.60-0.66). There was less agreement for grades of collateral supply (K-alpha = 0.56) or for identification of a perfusion defect on CTA-SI (K-alpha = 0.32). Radiology trainees performed as well as expert readers when additional training was undertaken (neuroradiology specialist trainees). Intra-observer agreement among experts provided similar results (K-alpha = 0.33-0.72). For most imaging characteristics assessed, CTA has moderate to substantial observer agreement in acute ischaemic stroke. Experienced readers and those with specialist training perform best. (orig.)

  4. Observer reliability of CT angiography in the assessment of acute ischaemic stroke: data from the Third International Stroke Trial

    International Nuclear Information System (INIS)

    Mair, Grant; Farrall, Andrew J.; Sellar, Robin J.; Mollison, Daisy; Sakka, Eleni; Palmer, Jeb; Wardlaw, Joanna M.; Kummer, Ruediger von; Adami, Alessandro; White, Philip M.; Adams, Matthew E.; Yan, Bernard; Demchuk, Andrew M.; Ramaswamy, Rajesh; Rodrigues, Mark A.; Samji, Karim; Baird, Andrew J.; Boyd, Elena V.; Cohen, Geoff; Perry, David; Sandercock, Peter A.G.; Lindley, Richard

    2015-01-01

    CT angiography (CTA) is often used for assessing patients with acute ischaemic stroke. Only limited observer reliability data exist. We tested inter- and intra-observer reliability for the assessment of CTA in acute ischaemic stroke. We selected 15 cases from the Third International Stroke Trial (IST-3, ISRCTN25765518) with various degrees of arterial obstruction in different intracranial locations on CTA. To assess inter-observer reliability, seven members of the IST-3 expert image reading panel (>5 years experience reading CTA) and seven radiology trainees (<2 years experience) rated all 15 scans independently and blind to clinical data for: presence (versus absence) of any intracranial arterial abnormality (stenosis or occlusion), severity of arterial abnormality using relevant scales (IST-3 angiography score, Thrombolysis in Cerebral Infarction (TICI) score, Clot Burden Score), collateral supply and visibility of a perfusion defect on CTA source images (CTA-SI). Intra-observer reliability was assessed using independently repeated expert panel scan ratings. We assessed observer agreement with Krippendorff's-alpha (K-alpha). Among experienced observers, inter-observer agreement was substantial for the identification of any angiographic abnormality (K-alpha = 0.70) and with an angiography assessment scale (K-alpha = 0.60-0.66). There was less agreement for grades of collateral supply (K-alpha = 0.56) or for identification of a perfusion defect on CTA-SI (K-alpha = 0.32). Radiology trainees performed as well as expert readers when additional training was undertaken (neuroradiology specialist trainees). Intra-observer agreement among experts provided similar results (K-alpha = 0.33-0.72). For most imaging characteristics assessed, CTA has moderate to substantial observer agreement in acute ischaemic stroke. Experienced readers and those with specialist training perform best. (orig.)

  5. Improvement of internal tumor volumes of non-small cell lung cancer patients for radiation treatment planning using interpolated average CT in PET/CT.

    Directory of Open Access Journals (Sweden)

    Yao-Ching Wang

    Full Text Available Respiratory motion causes uncertainties in tumor edges on either computed tomography (CT or positron emission tomography (PET images and causes misalignment when registering PET and CT images. This phenomenon may cause radiation oncologists to delineate tumor volume inaccurately in radiotherapy treatment planning. The purpose of this study was to analyze radiology applications using interpolated average CT (IACT as attenuation correction (AC to diminish the occurrence of this scenario. Thirteen non-small cell lung cancer patients were recruited for the present comparison study. Each patient had full-inspiration, full-expiration CT images and free breathing PET images by an integrated PET/CT scan. IACT for AC in PET(IACT was used to reduce the PET/CT misalignment. The standardized uptake value (SUV correction with a low radiation dose was applied, and its tumor volume delineation was compared to those from HCT/PET(HCT. The misalignment between the PET(IACT and IACT was reduced when compared to the difference between PET(HCT and HCT. The range of tumor motion was from 4 to 17 mm in the patient cohort. For HCT and PET(HCT, correction was from 72% to 91%, while for IACT and PET(IACT, correction was from 73% to 93% (*p<0.0001. The maximum and minimum differences in SUVmax were 0.18% and 27.27% for PET(HCT and PET(IACT, respectively. The largest percentage differences in the tumor volumes between HCT/PET and IACT/PET were observed in tumors located in the lowest lobe of the lung. Internal tumor volume defined by functional information using IACT/PET(IACT fusion images for lung cancer would reduce the inaccuracy of tumor delineation in radiation therapy planning.

  6. Interobserver variability in the evaluation of internal carotid artery stenosis by CT angiography

    International Nuclear Information System (INIS)

    Carrascosa, Patricia; Meli, Francisco; Sampere, Tulio; Capunay, Carlos; Sanchez, Flavio; Carrascosa, Jorge

    2001-01-01

    Ischemic cerebral vascular events are primarily due to atherosclerotic narrowing of carotid bifurcation. Catheter Angiography (CA) is the best test for determining carotid artery stenosis, but it is invasive and has some risks. The purpose of this study was to evaluate CT Angiography (CTA) as a non-invasive method compared with CA. Different estimate procedures (NASCET, ESCT and area quantification) were done to compare the Sensitivity (S) and Specificity (E) of each one with CA. Afterwards, interobserver variability of the three procedures was evaluated. Thirty-eight internal carotid arteries were studied in 19 patients with transient ischemic attacks. CTA studies were done in a helical CT scanner. The images were evaluated in a workstation by two radiologists, who were blinded to the percentage of stenosis determined by CA. For statistical analysis, the measurement of stenosis percentage was divided in two groups: a) Negative (0-69%) and b) Positive:(70-100%). Kappa analysis (K) was used to determine the agreement of stenosis. Results: Observer 1: Sensitivity (S) NASCET: 94%, ESCT: 77% and area 94% and Specificity (E): 91%, 87,5% and 87,5%. Observer 2: 77%, 77% and 74%. The interobserver K was 0.83, 0792 and 0.78 for NASCET, ESCT and area quantification methods respectively. In conclusion, CTA has high S and E especially in NASCET and area quantification. (author)

  7. CT-angiography source images indicate less fatal outcome despite coma of patients in the Basilar Artery International Cooperation Study.

    Science.gov (United States)

    Pallesen, Lars P; Khomenko, Andrei; Dzialowski, Imanuel; Barlinn, Jessica; Barlinn, Kristian; Zerna, Charlotte; van der Hoeven, Erik Jrj; Algra, Ale; Kapelle, L Jaap; Michel, Patrik; Bodechtel, Ulf; Demchuk, Andrew M; Schonewille, Wouter; Puetz, Volker

    2017-02-01

    Background Coma is associated with poor outcome in patients with basilar artery occlusion. Aims We sought to assess whether the posterior circulation Acute Stroke Prognosis Early CT Score and the Pons-Midbrain Index applied to CT angiography source images predict the outcome of comatose patients in the Basilar Artery International Cooperation Study. Methods Basilar Artery International Cooperation Study was a prospective, observational registry of patients with acute basilar artery occlusion with 48 recruiting centers worldwide. We applied posterior circulation Acute Stroke Prognosis Early CT Score and Pons-Midbrain Index to CT angiography source images of Basilar Artery International Cooperation Study patients who presented with coma. We calculated adjusted risk ratios to assess the association of dichotomized posterior circulation Acute Stroke Prognosis Early CT Score (≥8 vs. International Cooperation Study registry, CT angiography source images were available for review in 158 patients. Among these, 78 patients (49%) presented with coma. Compared to non-comatose patients, comatose patients were more likely to die (risk ratios 2.34; CI 95% 1.56-3.52) and less likely to have a favourable outcome (risk ratios 0.44; CI 95% 0.24-0.80). Among comatose patients, a Pons-Midbrain Index < 3 was related to reduced mortality (adjusted RR 0.66; 95% CI 0.46-0.96), but not to favourable outcome (adjusted RR 1.19; 95% CI 0.39-3.62). Posterior circulation Acute Stroke Prognosis Early CT Score dichotomized at ≥ 8 vs. <8 was not significantly associated with death (adjusted RR 0.70; 95% CI 0.46-1.05). Conclusion In comatose patients with basilar artery occlusion, the extent of brainstem ischemia appears to be related to mortality but not to favourable outcome.

  8. Highlights of the 12th International Conference on Nuclear Cardiology and Cardiac CT.

    Science.gov (United States)

    Kitsiou, Anastasia; Dorbala, Sharmila; Scholte, Arthur J H A

    2015-09-01

    The 12th International Conference on Nuclear Cardiology and Cardiac CT was held from 3 to 5 May 2015 in Madrid, Spain. In this article, the three Congress Program Committee Chairs summarize selected highlights of the presented abstracts. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com. This article is being published concurrently in the Journal of Nuclear Cardiology (10.1007/s12350-015-0260-y) and European Heart Journal – Cardiovascular Imaging (10.1093/ehjci/jev179). The articles are identical except for minor stylistic and spelling differences in keeping with each journal’s style. Either citation can be used when citing this article.

  9. Arterial blood supply to midbrain, thalamus and internal capsule on CT, 3

    International Nuclear Information System (INIS)

    Takeshita, Gen; Ottomo, Michinori; Sasaki, Taisuke; Fukuda, Eiko.

    1984-01-01

    The selective injection of dye into the anterior choroidal artery (blue), the medial posterior choroidal artery (green), and the lateral posterior choroidal artery (red), using seven post-mortem brains, was performed. After fixation, sections parallel with the orbito-meatal line were obtained. The distribution of the anterior choroidal artery was visualized in the uncal region of the temporal lobe and the cerebral peduncle below the slice of the third ventricle. On the slice of the third ventricle, the lateral part of the geniculate region, the globus pallidus, and the posterior limb of the internal capsule were supplied by the anterior choroidal artery. The blood supply of the posterior limb of the internal capsule was also demonstrated on the slice of the anterior horn and on the body of the lateral ventricle. The distribution of the medial posterior choroidal artery was visualized in the tegmentum of the midbrain below the slice of the third ventricle, and on the slice of the anterior horn, the pineal body and the posterior part of the thalamus were also supplied. The distribution of the lateral posterior choroidal artery was visualized in the lateral part of the midbrain, around the red nucleus, below the slice of the third ventricle, and on the slice of the third ventricle, the upper part of the cerebral peduncle, the posterior part of the hypothalamus, and the medial part of the geniculate region were also supplied. Also, distribution to the medial and posterior parts of the thalamus was noted on the slice of the anterior horn. It was quite useful to identify the distribution of each choroidal artery on CT sections for the CT diagnosis of cerebrovascular disorders. (author)

  10. Procedure for measuring simultaneously the solar and visible properties of glazing with complex internal or external structures.

    Science.gov (United States)

    Gentle, A R; Smith, G B

    2014-10-20

    Accurate solar and visual transmittances of materials in which surfaces or internal structures are complex are often not easily amenable to standard procedures with laboratory-based spectrophotometers and integrating spheres. Localized "hot spots" of intensity are common in such materials, so data on small samples is unreliable. A novel device and simple protocols have been developed and undergone validation testing. Simultaneous solar and visible transmittance and reflectance data have been acquired for skylight components and multilayer polycarbonate roof panels. The pyranometer and lux sensor setups also directly yield "light coolness" in lumens/watt. Sample areas must be large, and, although mainly in sheet form, some testing has been done on curved panels. The instrument, its operation, and the simple calculations used are described. Results on a subset of diffuse and partially diffuse materials with no hot spots have been cross checked using 150 mm integrating spheres with a spectrophotometer and the Air Mass 1.5 spectrum. Indications are that results are as good or better than with such spheres for transmittance, but reflectance techniques need refinement for some sample types.

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

    International Nuclear Information System (INIS)

    Barlinn, Kristian; Kepplinger, Jessica; Siepmann, Timo; Pallesen, Lars-Peder; Bodechtel, Ulf; Reichmann, Heinz; Puetz, Volker; Floegel, Thomas; Kitzler, Hagen H.; Alexandrov, Andrei V.

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-15

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

  13. Micro-CT evaluation of internal adaptation in resin fillings with different dentin adhesives

    Directory of Open Access Journals (Sweden)

    Seung-Hoon Han

    2014-02-01

    Full Text Available Objectives The purpose of present study was to evaluate the internal adaptation of composite restorations using different adhesive systems. Materials and Methods Typical class I cavities were prepared in 32 human third molars. The teeth were divided into the following four groups: 3-step etch-and-rinse, 2-step etch-and-rinse, 2-step self-etch and 1-step self-etch system were used. After the dentin adhesives were applied, composite resins were filled and light-cured in two layers. Then, silver nitrate solution was infiltrated, and all of the samples were scanned by micro-CT before and after thermo-mechanical load cycling. For each image, the length to which silver nitrate infiltrated, as a percentage of the whole pulpal floor length, was calculated (%SP. To evaluate the internal adaptation using conventional method, the samples were cut into 3 pieces by two sectioning at an interval of 1 mm in the middle of the cavity and they were dyed with Rhodamine-B. The cross sections of the specimens were examined by stereomicroscope. The lengths of the parts where actual leakage was shown were measured and calculated as a percentage of real leakage (%RP. The values for %SP and %RP were compared. Results After thermo-mechanical loading, all specimens showed significantly increased %SP compared to before thermo-mechanical loading and 1-step self-etch system had the highest %SP (p < 0.05. There was a tendency for %SP and %RP to show similar microleakage percentage depending on its sectioning. Conclusions After thermo-mechanical load cycling, there were differences in internal adaptation among the groups using different adhesive systems.

  14. Retroperitoneal cystic lymphangioma with change of internal morphology on follow-up ultrasound and CT: a case report

    International Nuclear Information System (INIS)

    Shin, G. H; Lim, J. W.; Lee, D. H.; Ko, Y. T.; Kim, B. H.; Yang, M. H.

    1995-01-01

    We report a case of retroperitoneal cystic lymphangioma in an 65-year-old male. Two years prior to this admission, a mass was incidentally detected by ultrasound during hospitalization for the treatment of lung cancer. Ultrasound study showed a multiloculated cystic mass with debris and CT revealed a fat-fluid level within the mass. On two years follow-up, the mass has changed into a unicameral mass without internal echogenicity on US and homogeneous water-density mass on CT. The mass was removed by surgery and confirmed as retroperitoneal cystic lymphangioma

  15. Retroperitoneal cystic lymphangioma with change of internal morphology on follow-up ultrasound and CT: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Shin, G. H; Lim, J. W.; Lee, D. H.; Ko, Y. T.; Kim, B. H.; Yang, M. H. [College of Medicine, Kyung Hee University, Seoul (Korea, Republic of)

    1995-08-15

    We report a case of retroperitoneal cystic lymphangioma in an 65-year-old male. Two years prior to this admission, a mass was incidentally detected by ultrasound during hospitalization for the treatment of lung cancer. Ultrasound study showed a multiloculated cystic mass with debris and CT revealed a fat-fluid level within the mass. On two years follow-up, the mass has changed into a unicameral mass without internal echogenicity on US and homogeneous water-density mass on CT. The mass was removed by surgery and confirmed as retroperitoneal cystic lymphangioma.

  16. Space-borne observation of mesospheric bore by Visible and near Infrared Spectral Imager onboard the International Space Station

    Science.gov (United States)

    Hozumi, Y.; Saito, A.; Sakanoi, T.; Yamazaki, A.; Hosokawa, K.

    2017-12-01

    Mesospheric bores were observed by Visible and near Infrared Spectral Imager (VISI) of the ISS-IMAP mission (Ionosphere, Mesosphere, upper Atmosphere and Plasmasphere mapping mission from the International Space Station) in O2 airglow at 762 nm wavelength. The mesospheric bore is moving front of sharp jump followed by undulations or turbulence in the mesopause region. Since previous studies of mesospheric bore were mainly based on ground-based airglow imaging that is limited in field-of-view and observing site, little is known about its horizontal extent and global behavior. Space-borne imaging by ISS-IMAP/VISI provides an opportunity to study the mesospheric bore with a wide field-of-view and global coverage. A mesospheric bore was captured by VISI in two consecutive paths on 9 July 2015 over the south of African continent (48ºS - 54ºS and 15ºE). The wave front aligned with south-north direction and propagated to west. The phase velocity and wave length of the following undulation were estimated to 100 m/s and 30 km, respectively. Those parameters are similar to those reported by previous studies. 30º anti-clockwise rotation of the wave front was recognized in 100 min. Another mesospheric bore was captured on 9 May 2013 over the south Atlantic ocean (35ºS - 43ºS and 24ºW - 1ºE) with more than 2,200 km horizontal extent of wave front. The wave front aligned with southeast-northwest direction. Because the following undulation is recognized in the southwest side of the wave front, it is estimated to propagate to northeast direction. The wave front was modulated with 1,000 km wave length. This modulation implies inhomogeneity of the phase velocity.

  17. Use of internal references for assessing CT density measurements of the pelvis as replacement for use of an external phantom.

    Science.gov (United States)

    Boomsma, Martijn F; Slouwerhof, Inge; van Dalen, Jorn A; Edens, Mireille A; Mueller, Dirk; Milles, Julien; Maas, Mario

    2015-11-01

    The purpose of this research is to study the use of an internal reference standard for fat- and muscle as a replacement for an external reference standard with a phantom. By using a phantomless internal reference standard, Hounsfield unit (HU) measurements of various tissues can potentially be assessed in patients with a CT scan of the pelvis without an added phantom at time of CT acquisition. This paves the way for development of a tool for quantification of the change in tissue density in one patient over time and between patients. This could make every CT scan made without contrast available for research purposes. Fifty patients with unilateral metal-on-metal total hip replacements, scanned together with a calibration reference phantom used in bone mineral density measurements, were included in this study. On computed tomography scans of the pelvis without the use of intravenous iodine contrast, reference values for fat and muscle were measured in the phantom as well as within the patient's body. The conformity between the references was examined with the intra-class correlation coefficient. The mean HU (± SD) of reference values for fat for the internal- and phantom references were -91.5 (±7.0) and -90.9 (±7.8), respectively. For muscle, the mean HU (± SD) for the internal- and phantom references were 59.2 (±6.2) and 60.0 (±7.2), respectively. The intra-class correlation coefficients for fat and muscle were 0.90 and 0.84 respectively and show excellent agreement between the phantom and internal references. Internal references can be used with similar accuracy as references from an external phantom. There is no need to use an external phantom to asses CT density measurements of body tissue.

  18. Use of internal references for assessing CT density measurements of the pelvis as replacement for use of an external phantom

    Energy Technology Data Exchange (ETDEWEB)

    Boomsma, Martijn F.; Slouwerhof, Inge; Dalen, Jorn A. van [Isala Hospital, Department of Radiology, Zwolle (Netherlands); Edens, Mireille A. [Isala Hospital, Department of Innovation and Science, Zwolle (Netherlands); Mueller, Dirk [Philips Healthcare systems, Hamburg (Germany); Milles, Julien [Philips Healthcare Benelux, Eindhoven (Netherlands); Maas, Mario [AMC, Department of Radiology, Amsterdam (Netherlands)

    2015-11-15

    The purpose of this research is to study the use of an internal reference standard for fat- and muscle as a replacement for an external reference standard with a phantom. By using a phantomless internal reference standard, Hounsfield unit (HU) measurements of various tissues can potentially be assessed in patients with a CT scan of the pelvis without an added phantom at time of CT acquisition. This paves the way for development of a tool for quantification of the change in tissue density in one patient over time and between patients. This could make every CT scan made without contrast available for research purposes. Fifty patients with unilateral metal-on-metal total hip replacements, scanned together with a calibration reference phantom used in bone mineral density measurements, were included in this study. On computed tomography scans of the pelvis without the use of intravenous iodine contrast, reference values for fat and muscle were measured in the phantom as well as within the patient's body. The conformity between the references was examined with the intra-class correlation coefficient. The mean HU (± SD) of reference values for fat for the internal- and phantom references were -91.5 (±7.0) and -90.9 (±7.8), respectively. For muscle, the mean HU (± SD) for the internal- and phantom references were 59.2 (±6.2) and 60.0 (±7.2), respectively. The intra-class correlation coefficients for fat and muscle were 0.90 and 0.84 respectively and show excellent agreement between the phantom and internal references. Internal references can be used with similar accuracy as references from an external phantom. There is no need to use an external phantom to asses CT density measurements of body tissue. (orig.)

  19. Semi-automatic quantitative measurements of intracranial internal carotid artery stenosis and calcification using CT angiography

    International Nuclear Information System (INIS)

    Bleeker, Leslie; Berg, Rene van den; Majoie, Charles B.; Marquering, Henk A.; Nederkoorn, Paul J.

    2012-01-01

    Intracranial carotid artery atherosclerotic disease is an independent predictor for recurrent stroke. However, its quantitative assessment is not routinely performed in clinical practice. In this diagnostic study, we present and evaluate a novel semi-automatic application to quantitatively measure intracranial internal carotid artery (ICA) degree of stenosis and calcium volume in CT angiography (CTA) images. In this retrospective study involving CTA images of 88 consecutive patients, intracranial ICA stenosis was quantitatively measured by two independent observers. Stenoses were categorized with cutoff values of 30% and 50%. The calcification in the intracranial ICA was qualitatively categorized as absent, mild, moderate, or severe and quantitatively measured using the semi-automatic application. Linear weighted kappa values were calculated to assess the interobserver agreement of the stenosis and calcium categorization. The average and the standard deviation of the quantitative calcium volume were calculated for the calcium categories. For the stenosis measurements, the CTA images of 162 arteries yielded an interobserver correlation of 0.78 (P < 0.001). Kappa values of the categorized stenosis measurements were moderate: 0.45 and 0.58 for cutoff values of 30% and 50%, respectively. The kappa value for the calcium categorization was 0.62, with a good agreement between the qualitative and quantitative calcium assessment. Quantitative degree of stenosis measurement of the intracranial ICA on CTA is feasible with a good interobserver agreement ICA. Qualitative calcium categorization agrees well with quantitative measurements. (orig.)

  20. Means to verify the accuracy of CT systems for metrology applications (In the Absence of Established International Standards)

    International Nuclear Information System (INIS)

    Lettenbauer, H.; Georgi, B.; Weib, D.

    2007-01-01

    X-ray computed tomography (CT) reconstructs an unknown object from X-ray projections and has long been used for qualitative investigation of internal structures in industrial applications. Recently there has been increased interest in applying X-ray cone beam CT to the task of high-precision dimensional measurements of machined parts, since it is a relatively fast method of measuring both inner and outer geometries of arbitrary complexity. The important information for the user in dimensional metrology is if measured elements of a machined part are within the defined tolerances or not. In order to qualify cone beam CT as an established measurement technology, it must be qualified in the same manner as established measurement technologies such as coordinate measurement machines (CMMs) with tactile or optical sensors. In international standards artefacts are defined that are calibrated by certified institutions. These artefacts are defined by certain geometrical elements. CT measurements are performed on the reconstructed object volume, either directly or using an intermediate surface-extraction step. The results of these measurements have to be compared to the values of the calibrated elements; the level of agreement of the results defines the accuracy of the measurements. By using established methods to define measurement uncertainty a very high level of acceptance in dimensional metrology can be reached for the user. Only if results are comparable to standards of the established technologies the barriers of entry into metrology will be removed and all benefits of this technology will be available for the user. (authors)

  1. 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.)

  2. Definition of internal target volume and domestric study for hepatocellular carcinoma using four-dimensional CT

    International Nuclear Information System (INIS)

    Xi Mian; Liu Mengzhong; Deng Xiaowu; Zhang Li; Huang Xiaoyan; Cai Ling

    2009-01-01

    Objective: To define individualized internal target volume (ITV) for hepatocellular carcinoma using four-dimensional (4D) CT, and to compare the differences in target volume definition and dose distribution among 3D, 4D and respiratory-gated plans. Methods: 4DCT scanning was obtained for 12 patients with hepatocellular. Gross tumor volume (GTV), clinical target volume (CTV) and normal tissues were contoured on all 10 respiratory phases of 4DCT images. The 3D, 4D and gated treatment plans were prepared for each patient using three different planning target volumes (PTVs): 1) PTV 3D was derived from a single CTV plus conventional margins; 2) PTV 4D was derived from ITV 4D , which encompassed all 10 CTVs plus setup margins (SMs); 3) PT Gating was derived from ITV Gating , which encompassed 3 CTVs within gating-window at end-expiration plus SMs. The PTV volume and dose distribution were compared among different plans. Results: The PTV3D was the largest in all 12 patients, but still missed partial target volume in 5 patients when comparing with PTV4D. Both the 4D plans and the gated plans spared more normal tissues than the 3D plans, especially the liver. Without increasing normal tissue dose, the 4D plans allowed for increasing the calculated dose from (50.8 ± 2.0) Gy (3D plans) to (54.7 ± 3.3) Gy, and the gated plans could further increase the dose to (58.0 ± 3.9) Gy. Conclusions: The 4DCT-based plans can ensure optimal target coverage with less irradiation of normal tissues and allow dose escalation when compared with 3D plans. Respiratory gated radiotherapy can further reduce the target volumes to spare more surrounding tissues, especially for patients with large extent of respiratory mobility. (authors)

  3. Nerve canals at the fundus of the internal auditory canal on high-resolution temporal bone CT

    International Nuclear Information System (INIS)

    Ji, Yoon Ha; Youn, Eun Kyung; Kim, Seung Chul

    2001-01-01

    To identify and evaluate the normal anatomy of nerve canals in the fundus of the internal auditory canal which can be visualized on high-resolution temporal bone CT. We retrospectively reviewed high-resolution (1 mm thickness and interval contiguous scan) temporal bone CT images of 253 ears in 150 patients who had not suffered trauma or undergone surgery. Those with a history of uncomplicated inflammatory disease were included, but those with symptoms of vertigo, sensorineural hearing loss, or facial nerve palsy were excluded. Three radiologists determined the detectability and location of canals for the labyrinthine segment of the facial, superior vestibular and cochlear nerve, and the saccular branch and posterior ampullary nerve of the inferior vestibular nerve. Five bony canals in the fundus of the internal auditory canal were identified as nerve canals. Four canals were identified on axial CT images in 100% of cases; the so-called singular canal was identified in only 68%. On coronal CT images, canals for the labyrinthine segment of the facial and superior vestibular nerve were seen in 100% of cases, but those for the cochlear nerve, the saccular branch of the inferior vestibular nerve, and the singular canal were seen in 90.1%, 87.4% and 78% of cases, respectiveIy. In all detectable cases, the canal for the labyrinthine segment of the facial nerve was revealed as one which traversed anterolateralIy, from the anterosuperior portion of the fundus of the internal auditory canal. The canal for the cochlear nerve was located just below that for the labyrinthine segment of the facial nerve, while that canal for the superior vestibular nerve was seen at the posterior aspect of these two canals. The canal for the saccular branch of the inferior vestibular nerve was located just below the canal for the superior vestibular nerve, and that for the posterior ampullary nerve, the so-called singular canal, ran laterally or posteolateralIy from the posteroinferior aspect of

  4. Nerve canals at the fundus of the internal auditory canal on high-resolution temporal bone CT

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Yoon Ha; Youn, Eun Kyung; Kim, Seung Chul [Sungkyunkwan Univ., School of Medicine, Seoul (Korea, Republic of)

    2001-12-01

    To identify and evaluate the normal anatomy of nerve canals in the fundus of the internal auditory canal which can be visualized on high-resolution temporal bone CT. We retrospectively reviewed high-resolution (1 mm thickness and interval contiguous scan) temporal bone CT images of 253 ears in 150 patients who had not suffered trauma or undergone surgery. Those with a history of uncomplicated inflammatory disease were included, but those with symptoms of vertigo, sensorineural hearing loss, or facial nerve palsy were excluded. Three radiologists determined the detectability and location of canals for the labyrinthine segment of the facial, superior vestibular and cochlear nerve, and the saccular branch and posterior ampullary nerve of the inferior vestibular nerve. Five bony canals in the fundus of the internal auditory canal were identified as nerve canals. Four canals were identified on axial CT images in 100% of cases; the so-called singular canal was identified in only 68%. On coronal CT images, canals for the labyrinthine segment of the facial and superior vestibular nerve were seen in 100% of cases, but those for the cochlear nerve, the saccular branch of the inferior vestibular nerve, and the singular canal were seen in 90.1%, 87.4% and 78% of cases, respectiveIy. In all detectable cases, the canal for the labyrinthine segment of the facial nerve was revealed as one which traversed anterolateralIy, from the anterosuperior portion of the fundus of the internal auditory canal. The canal for the cochlear nerve was located just below that for the labyrinthine segment of the facial nerve, while that canal for the superior vestibular nerve was seen at the posterior aspect of these two canals. The canal for the saccular branch of the inferior vestibular nerve was located just below the canal for the superior vestibular nerve, and that for the posterior ampullary nerve, the so-called singular canal, ran laterally or posteolateralIy from the posteroinferior aspect of

  5. Nontumorous enlargement of the internal auditory canal. A risk factor for sensorineural hearing loss? A high resolution CT-study

    Energy Technology Data Exchange (ETDEWEB)

    Stimmer, H.; Rummeny, E.J. [Technical University Munich, Klinikum rechts der Isar (Germany). Dept. of Radiology; Niedermeyer, H.P. [Technical University Munich, Klinikum rechts der Isar (Germany). ENT-Clinic; Kehl, V. [Technical University Munich, Klinikum rechts der Isar (Germany). Inst. for Medical Statistics and Epidemiology

    2015-06-15

    First aim of the study was to define normal shape and diameter of the internal auditory canal (IAC). In the second part the clinical relevance of IAC-enlargement was analyzed, considering also lesions of the subtle structures at the fundus of the internal auditory canal. 440 high resolution CT-scans of the temporal bone were used for retrospective analysis of the internal auditory canal and its fundus region. The mean value of the IAC diameter in axial and coronal plane was determined. In 20 of 440 patients IAC enlargement was found. In the group with pronounced enlargement (3fold SD) nearly all patients suffered from hearing impairment. In some of them we found structural abnormalities near the IAC fundus in the CSF/perilymph border zone. A new CT-based definition of normal shape and diameter of the internal auditory canal is presented. There is some evidence that a pathologic transmission of CSF-pressure in case of IAC-enlargement and/or abnormal fistulous communications could play an important role in the pathophysiology of hearing loss.

  6. Differences in the definition of internal target volumes using slow CT alone or in combination with thin-slice CT under breath-holding conditions during the planning of stereotactic radiotherapy for lung cancer

    International Nuclear Information System (INIS)

    Seki, Satoshi; Kunieda, Etsuo; Takeda, Atsuya; Nagaoka, Tomoaki; Deloar, Hossain M.; Kawase, Takatsugu; Fukada, Junichi; Kawaguchi, Osamu; Uematsu, Minoru; Kubo, Atsushi

    2007-01-01

    Purpose: To investigate how the delineations of the internal target volume (ITV) made from 'slow' CT alter with reference to 'thin-slice' CT. Materials and methods: Thin-slice CT images taken under breath-holding conditions and slow CT images taken under shallow-breathing conditions (8 s/image) of 11 lung cancers were used for this study. Five radiation oncologists delineated ITV of the 11 lesions using slow CT images (ITV1), and then redefined them with reference to thin-slice CT images (ITV2). SD-images (standard deviation image) were created for all patients from ITV images in order to visualize the regional variation of the ITVs. Results: The mean value of ITV2 was smaller than that initially defined by ITV1. There was no significant change in ITV1 and ITV2 between operators with regard to standard deviation in volume. There was a significant difference in the distribution of the ratio of ITV1 to ITV2 obtained on thin-slice CTs between cases with and without ground glass opacity. In cases without ground glass opacity there was a tendency for ITV2 to have a smaller volume than ITV1. Conclusions: Combined use of slow CT and thin-slice CT in delineation of ITV contours appeared to be useful in making adjustments for obscured tumor images caused by respiratory movement

  7. Diagnostic and Prognostic Impact of pc-ASPECTS Applied to Perfusion CT in the Basilar Artery International Cooperation Study.

    Science.gov (United States)

    Pallesen, Lars-Peder; Gerber, Johannes; Dzialowski, Imanuel; van der Hoeven, Erik J R J; Michel, Patrik; Pfefferkorn, Thomas; Ozdoba, Christoph; Kappelle, L Jaap; Wiedemann, Baerbel; Khomenko, Andrei; Algra, Ale; Hill, Michael D; von Kummer, Ruediger; Demchuk, Andrew M; Schonewille, Wouter J; Puetz, Volker

    2015-01-01

    The posterior circulation Acute Stroke Prognosis Early CT Score (pc-APECTS) applied to CT angiography source images (CTA-SI) predicts the functional outcome of patients in the Basilar Artery International Cooperation Study (BASICS). We assessed the diagnostic and prognostic impact of pc-ASPECTS applied to perfusion CT (CTP) in the BASICS registry population. We applied pc-ASPECTS to CTA-SI and cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) parameter maps of BASICS patients with CTA and CTP studies performed. Hypoattenuation on CTA-SI, relative reduction in CBV or CBF, or relative increase in MTT were rated as abnormal. CTA and CTP were available in 27/592 BASICS patients (4.6%). The proportion of patients with any perfusion abnormality was highest for MTT (93%; 95% confidence interval [CI], 76%-99%), compared with 78% (58%-91%) for CTA-SI and CBF, and 46% (27%-67%) for CBV (P < .001). All 3 patients with a CBV pc-ASPECTS < 8 compared to 6/23 patients with a CBV pc-ASPECTS ≥ 8 had died at 1 month (RR 3.8; 95% CI, 1.9-7.6). CTP was performed in a minority of the BASICS registry population. Perfusion disturbances in the posterior circulation were most pronounced on MTT parameter maps. CBV pc-ASPECTS < 8 may indicate patients with high case fatality. Copyright © 2014 by the American Society of Neuroimaging.

  8. Internal respiratory surrogate in multislice 4D CT using a combination of Fourier transform and anatomical features

    International Nuclear Information System (INIS)

    Hui, Cheukkai; Suh, Yelin; Robertson, Daniel; Beddar, Sam; Pan, Tinsu; Das, Prajnan; Crane, Christopher H.

    2015-01-01

    Purpose: The purpose of this study was to develop a novel algorithm to create a robust internal respiratory signal (IRS) for retrospective sorting of four-dimensional (4D) computed tomography (CT) images. Methods: The proposed algorithm combines information from the Fourier transform of the CT images and from internal anatomical features to form the IRS. The algorithm first extracts potential respiratory signals from low-frequency components in the Fourier space and selected anatomical features in the image space. A clustering algorithm then constructs groups of potential respiratory signals with similar temporal oscillation patterns. The clustered group with the largest number of similar signals is chosen to form the final IRS. To evaluate the performance of the proposed algorithm, the IRS was computed and compared with the external respiratory signal from the real-time position management (RPM) system on 80 patients. Results: In 72 (90%) of the 4D CT data sets tested, the IRS computed by the authors’ proposed algorithm matched with the RPM signal based on their normalized cross correlation. For these data sets with matching respiratory signals, the average difference between the end inspiration times (Δt ins ) in the IRS and RPM signal was 0.11 s, and only 2.1% of Δt ins were more than 0.5 s apart. In the eight (10%) 4D CT data sets in which the IRS and the RPM signal did not match, the average Δt ins was 0.73 s in the nonmatching couch positions, and 35.4% of them had a Δt ins greater than 0.5 s. At couch positions in which IRS did not match the RPM signal, a correlation-based metric indicated poorer matching of neighboring couch positions in the RPM-sorted images. This implied that, when IRS did not match the RPM signal, the images sorted using the IRS showed fewer artifacts than the clinical images sorted using the RPM signal. Conclusions: The authors’ proposed algorithm can generate robust IRSs that can be used for retrospective sorting of 4D CT data

  9. Internal respiratory surrogate in multislice 4D CT using a combination of Fourier transform and anatomical features

    Energy Technology Data Exchange (ETDEWEB)

    Hui, Cheukkai; Suh, Yelin [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Robertson, Daniel; Beddar, Sam, E-mail: abeddar@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and Department of Radiation Physics, The University of Texas Graduate School of Biomedical Sciences, Houston, Texas 77030 (United States); Pan, Tinsu [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and Department of Imaging Physics, The University of Texas Graduate School of Biomedical Sciences, Houston, Texas 77030 (United States); Das, Prajnan; Crane, Christopher H. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

    2015-07-15

    Purpose: The purpose of this study was to develop a novel algorithm to create a robust internal respiratory signal (IRS) for retrospective sorting of four-dimensional (4D) computed tomography (CT) images. Methods: The proposed algorithm combines information from the Fourier transform of the CT images and from internal anatomical features to form the IRS. The algorithm first extracts potential respiratory signals from low-frequency components in the Fourier space and selected anatomical features in the image space. A clustering algorithm then constructs groups of potential respiratory signals with similar temporal oscillation patterns. The clustered group with the largest number of similar signals is chosen to form the final IRS. To evaluate the performance of the proposed algorithm, the IRS was computed and compared with the external respiratory signal from the real-time position management (RPM) system on 80 patients. Results: In 72 (90%) of the 4D CT data sets tested, the IRS computed by the authors’ proposed algorithm matched with the RPM signal based on their normalized cross correlation. For these data sets with matching respiratory signals, the average difference between the end inspiration times (Δt{sub ins}) in the IRS and RPM signal was 0.11 s, and only 2.1% of Δt{sub ins} were more than 0.5 s apart. In the eight (10%) 4D CT data sets in which the IRS and the RPM signal did not match, the average Δt{sub ins} was 0.73 s in the nonmatching couch positions, and 35.4% of them had a Δt{sub ins} greater than 0.5 s. At couch positions in which IRS did not match the RPM signal, a correlation-based metric indicated poorer matching of neighboring couch positions in the RPM-sorted images. This implied that, when IRS did not match the RPM signal, the images sorted using the IRS showed fewer artifacts than the clinical images sorted using the RPM signal. Conclusions: The authors’ proposed algorithm can generate robust IRSs that can be used for retrospective

  10. Pancreatic gross tumor volume contouring on computed tomography (CT) compared with magnetic resonance imaging (MRI): Results of an international contouring conference.

    Science.gov (United States)

    Hall, William A; Heerkens, Hanne D; Paulson, Eric S; Meijer, Gert J; Kotte, Alexis N; Knechtges, Paul; Parikh, Parag J; Bassetti, Michael F; Lee, Percy; Aitken, Katharine L; Palta, Manisha; Myrehaug, Sten; Koay, Eugene J; Portelance, Lorraine; Ben-Josef, Edgar; Erickson, Beth A

    Accurate identification of the gross tumor volume (GTV) in pancreatic adenocarcinoma is challenging. We sought to understand differences in GTV delineation using pancreatic computed tomography (CT) compared with magnetic resonance imaging (MRI). Twelve attending radiation oncologists were convened for an international contouring symposium. All participants had a clinical and research interest in pancreatic adenocarcinoma. CT and MRI scans from 3 pancreatic cases were used for contouring. CT and MRI GTVs were analyzed and compared. Interobserver variability was compared using Dice's similarity coefficient (DSC), Hausdorff distances, and Jaccard indices. Mann-Whitney tests were used to check for significant differences. Consensus contours on CT and MRI scans and constructed count maps were used to visualize the agreement. Agreement regarding the optimal method to determine GTV definition using MRI was reached. Six contour sets (3 from CT and 3 from MRI) were obtained and compared for each observer, totaling 72 contour sets. The mean volume of contours on CT was significantly larger at 57.48 mL compared with a mean of 45.76 mL on MRI, P = .011. The standard deviation obtained from the CT contours was significantly larger than the standard deviation from the MRI contours (P = .027). The mean DSC was 0.73 for the CT and 0.72 for the MRI (P = .889). The conformity index measurement was similar for CT and MRI (P = .58). Count maps were created to highlight differences in the contours from CT and MRI. Using MRI as a primary image set to define a pancreatic adenocarcinoma GTV resulted in smaller contours compared with CT. No differences in DSC or the conformity index were seen between MRI and CT. A stepwise method is recommended as an approach to contour a pancreatic GTV using MRI. Copyright © 2017 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

  11. Making the invisible, visible: challenging the knowledge structures inherent in International Relations Theory in order to create knowledge plural curricula

    Directory of Open Access Journals (Sweden)

    Jacqueline de Matos-Ala

    2018-02-01

    Full Text Available Abstract This article problematizes the lack of plurality of knowledges in International Relations theory curricula. The increase in knowledges and scholarship from the South has not seemingly filtered into International Relations theory curricula significantly. Thus Western knowledges still dominates the narrative. It investigates how knowledge structures inherent in the discipline coupled with Western centric ontology and epistemology function to exclude or marginalize knowledge that does not conform to specific criteria. I demonstrate how the third year IR theory curriculum at Wits University, has engaged with discipline’s knowledge structures as well as its ontology and epistemology to develop a knowledge plural curricula.

  12. Influence of Manufacturing Methods of Implant-Supported Crowns on External and Internal Marginal Fit: A Micro-CT Analysis.

    Science.gov (United States)

    Moris, Izabela C M; Monteiro, Silas Borges; Martins, Raíssa; Ribeiro, Ricardo Faria; Gomes, Erica A

    2018-01-01

    To evaluate the influence of different manufacturing methods of single implant-supported metallic crowns on the internal and external marginal fit through computed microtomography. Forty external hexagon implants were divided into 4 groups ( n = 8), according to the manufacturing method: GC, conventional casting; GI, induction casting; GP, plasma casting; and GCAD, CAD/CAM machining. The crowns were attached to the implants with insertion torque of 30 N·cm. The external (vertical and horizontal) marginal fit and internal fit were assessed through computed microtomography. Internal and external marginal fit data ( μ m) were submitted to a one-way ANOVA and Tukey's test ( α = .05). Qualitative evaluation of the images was conducted by using micro-CT. The statistical analysis revealed no significant difference between the groups for vertical misfit ( P = 0.721). There was no significant difference ( P > 0.05) for the internal and horizontal marginal misfit in the groups GC, GI, and GP, but it was found for the group GCAD ( P ≤ 0.05). Qualitative analysis revealed that most of the samples of cast groups exhibited crowns underextension while the group GCAD showed overextension. The manufacturing method of the crowns influenced the accuracy of marginal fit between the prosthesis and implant. The best results were found for the crowns fabricated through CAD/CAM machining.

  13. Influence of Manufacturing Methods of Implant-Supported Crowns on External and Internal Marginal Fit: A Micro-CT Analysis

    Directory of Open Access Journals (Sweden)

    Izabela C. M. Moris

    2018-01-01

    Full Text Available Aim. To evaluate the influence of different manufacturing methods of single implant-supported metallic crowns on the internal and external marginal fit through computed microtomography. Methods. Forty external hexagon implants were divided into 4 groups (n=8, according to the manufacturing method: GC, conventional casting; GI, induction casting; GP, plasma casting; and GCAD, CAD/CAM machining. The crowns were attached to the implants with insertion torque of 30 N·cm. The external (vertical and horizontal marginal fit and internal fit were assessed through computed microtomography. Internal and external marginal fit data (μm were submitted to a one-way ANOVA and Tukey’s test (α=.05. Qualitative evaluation of the images was conducted by using micro-CT. Results. The statistical analysis revealed no significant difference between the groups for vertical misfit (P=0.721. There was no significant difference (P>0.05 for the internal and horizontal marginal misfit in the groups GC, GI, and GP, but it was found for the group GCAD (P≤0.05. Qualitative analysis revealed that most of the samples of cast groups exhibited crowns underextension while the group GCAD showed overextension. Conclusions. The manufacturing method of the crowns influenced the accuracy of marginal fit between the prosthesis and implant. The best results were found for the crowns fabricated through CAD/CAM machining.

  14. Use of lead shielding on pregnant patients undergoing CT scans: Results of an international survey

    Energy Technology Data Exchange (ETDEWEB)

    Iball, Gareth R., E-mail: gri@medphysics.leeds.ac.u [Department of Medical Physics and Engineering, Old Medical School, Leeds General Infirmary, Leeds, W. Yorkshire LS1 3EX (United Kingdom); Brettle, David S. [Department of Medical Physics and Engineering, Old Medical School, Leeds General Infirmary, Leeds, W. Yorkshire LS1 3EX (United Kingdom)

    2011-05-15

    Aim: An online survey has been used to assess the use of abdominal lead shielding on pregnant patients undergoing CT scans. The aim of the study was to identify potential geographical variations in the use of such shielding as well as the opinions of the users in terms of the weight, manoeuvrability and ergonomics of the lead shields. Materials and methods: The online questionnaire was distributed to CT Radiographers in the UK, Europe, North America and Australia and responses were gathered electronically over a six month period. All completed responses were downloaded and subsequently analysed for each geographical region. Results: In total, 390 completed questionnaires were received with over 100 from each of the UK, North America and Australia. The use of lead shielding was found to vary significantly across the globe with the highest usage in North America (94.5%) and the lowest usage in Europe (46.3%). Approximately 20% of all respondents said that they experienced occupationally related back pain and 25% of all respondents said that patients complained about the weight of the shielding. Conclusion: Significant geographical variations in both the use of lead shielding for foetal radiation protection and the users' opinions of the shielding devices that are used have been identified and it has become clear that existing shielding solutions are not optimised for this task.

  15. Risk stratification for avascular necrosis of the femoral head after internal fixation of femoral neck fractures by post-operative SPECT/CT

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sang Won; Oh, Min Young; Yoon, Seok Ho; Kim, Jin Soo; Chang, Jae Suk; Ryu, Jin Sook [Asan Medical CenterUniversity of Ulsan College of Medicine, Seoul (Korea, Republic of); Kim, Ji Wan [Dept. of Orthopedic Surgery, Haeundae Paik Hospital, Inje University, Busan (Korea, Republic of)

    2017-03-15

    Avascular necrosis (AVN) of the femoral head is a major complication after internal fixation of a femoral neck fracture and determines the functional prognosis. We investigated postoperative bone single-photon emission computed tomography/computed tomography (SPECT/CT) for assessing the risk of femoral head AVN. We retrospectively reviewed 53 consecutive patients who underwent bone SPECT/CT within 2 weeks of internal fixation of a femoral neck fracture and follow-up serial hip radiographs over at least 12 months. Nine patients developed femoral head AVN. In 15 patients who showed normal uptake on immediate postoperative SPECT/CT, no AVN occurred, whereas 9 of 38 patients who showed cold defects of the femoral head later developed AVN. The negative predictive value of immediate postoperative SPECT/CT for AVN was 100 %, whereas the positive predictive value was 24 %. Among 38 patients with cold defects, 1 developed AVN 3 months postoperatively. A follow-up bone SPECT/CT was performed in the other 37 patients at 2–10 months postoperatively. The follow-up bone SPECT/CT revealed completely normalized femoral head uptake in 27, partially normalized uptake in 8, and persistent cold defects in 2 patients. AVN developed in 3.7 % (1/27), 62.5 % (5/8), and 100 % (2/2) of each group, respectively. According to the time point of imaging, radiotracer uptake patterns of the femoral head on postoperative bone SPECT/CT indicate the risk of AVN after internal fixation of femoral neck fractures differently. Postoperative bone SPECT/CT may help orthopedic surgeons determine the appropriate follow-up of these patients.

  16. Risk stratification for avascular necrosis of the femoral head after internal fixation of femoral neck fractures by post-operative SPECT/CT

    International Nuclear Information System (INIS)

    Han, Sang Won; Oh, Min Young; Yoon, Seok Ho; Kim, Jin Soo; Chang, Jae Suk; Ryu, Jin Sook; Kim, Ji Wan

    2017-01-01

    Avascular necrosis (AVN) of the femoral head is a major complication after internal fixation of a femoral neck fracture and determines the functional prognosis. We investigated postoperative bone single-photon emission computed tomography/computed tomography (SPECT/CT) for assessing the risk of femoral head AVN. We retrospectively reviewed 53 consecutive patients who underwent bone SPECT/CT within 2 weeks of internal fixation of a femoral neck fracture and follow-up serial hip radiographs over at least 12 months. Nine patients developed femoral head AVN. In 15 patients who showed normal uptake on immediate postoperative SPECT/CT, no AVN occurred, whereas 9 of 38 patients who showed cold defects of the femoral head later developed AVN. The negative predictive value of immediate postoperative SPECT/CT for AVN was 100 %, whereas the positive predictive value was 24 %. Among 38 patients with cold defects, 1 developed AVN 3 months postoperatively. A follow-up bone SPECT/CT was performed in the other 37 patients at 2–10 months postoperatively. The follow-up bone SPECT/CT revealed completely normalized femoral head uptake in 27, partially normalized uptake in 8, and persistent cold defects in 2 patients. AVN developed in 3.7 % (1/27), 62.5 % (5/8), and 100 % (2/2) of each group, respectively. According to the time point of imaging, radiotracer uptake patterns of the femoral head on postoperative bone SPECT/CT indicate the risk of AVN after internal fixation of femoral neck fractures differently. Postoperative bone SPECT/CT may help orthopedic surgeons determine the appropriate follow-up of these patients

  17. Can the subaltern speak? Visibility of international migrants with communication and swallowing disabilities in the World Report on Disability.

    Science.gov (United States)

    Pillay, Mershen

    2013-02-01

    Wylie, McAllister, Davidson, and Marshal (2013) argued that the speech-language pathology profession must be encouraged to consider novel ways to deliver equitable services to people with communication disorders. People with communication disorders include the world's 215 million international migrants who deserve unique commentary when considering disability in the world. Hence, this paper focuses on invisibility of international migrants with communication or swallowing disorders in the World Report on Disability. The analysis of people with disabilities is biased towards citizenship. What of those who are non-citizens? Three issues are highlighted: (a) the demographic construction of migrants; (b) management of communication disability within the migrant patient-speech language pathologist dyad; and (c) strategic re-prioritization of dysphagia as a disability. While relevant to all people, re-prioritization of dysphagia as an impairment (of eating or drinking) resulting in restricted mealtime participation is especially relevant to the healthcare of international migrants. This issue is discussed in terms of how safe or adequate eating and drinking ought to constitute essential discharge criteria in medical settings where discharge (often resulting in deportation) may be decided on one's ability to walk or talk.

  18. UVISS preliminary visibility analysis

    DEFF Research Database (Denmark)

    Betto, Maurizio

    1998-01-01

    The goal of this work is to obtain a preliminary assessment of the sky visibility for anastronomical telescope located on the express pallet of the International SpaceStation (ISS)} taking into account the major constraints imposed on the instrument by the ISSattitude and structure. Part of the w......The goal of this work is to obtain a preliminary assessment of the sky visibility for anastronomical telescope located on the express pallet of the International SpaceStation (ISS)} taking into account the major constraints imposed on the instrument by the ISSattitude and structure. Part...... of the work is also to setup the kernel of a software tool for the visibility analysis thatshould be easily expandable to consider more complex strucures for future activities.This analysis is part of the UVISS assessment study and it is meant to provide elementsfor the definition and the selection...

  19. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... sinus cavities – hollow, air-filled spaces within the bones of the face surrounding the nasal cavity. CT ... CD or DVD. CT images of internal organs, bones, soft tissue and blood vessels provide greater detail ...

  20. Las revistas argentinas de filosofía: visibilidad en bases de datos internacionales Argentine journals of philosophy: visibility in international databases

    Directory of Open Access Journals (Sweden)

    Susana Romanos De Tiratel

    2005-12-01

    Full Text Available El artículo proporciona una breve introducción al escenario actual donde se desenvuelve la publicación periódica y su compleja problemática enfatizando en América Latina y enfocando el estudio en las revistas argentinas de Filosofía. Dentro del marco teórico provisto por Keresztesi respecto de las interrelaciones entre investigación y bibliografía, se aplican métodos cuantitativos para determinar los indicadores de representatividad, de visibilidad y de vacancia de las revistas argentinas de Filosofía. Las fórmulas resultantes se utilizan en bases de datos internacionales pluridisciplinarias, unidisciplinarias y de área. Finalmente, se discuten ciertos aspectos que se derivan del estudio realizado; se concluye que a menor cantidad de títulos publicados, mayor índice de visibilidad en bases de datos internacionales y, finalmente, se aportan datos comprobados para la toma de decisiones en unidades de información dedicadas a la Filosofía.The article introduces periodical publication and addresses the questions raised in connection with this format, focusing on Philosophy's journals in Argentina. Within Keresztesi's framework of reference as regards the research/ bibliography relationship, some quantitative methods to determine indicators of representativity, visibility and vacancy of Argentinean journals in Philosophy are applied. The research examines data available in both single-discipline and multidisciplinary international and Latin-American bases. Matters arising as a result of our study are discussed and our conclusion is that the fewer the titles, the greater the visibility in international databases. Finally, we provide checked data for decision making in Philosophy information units.

  1. The effect of irregular breathing patterns on internal target volumes in four-dimensional CT and cone-beam CT images in the context of stereotactic lung radiotherapy

    International Nuclear Information System (INIS)

    Clements, N.; Kron, T.; Roxby, P.; Franich, R.; Dunn, L.; Aarons, Y.; Chesson, B.; Siva, S.; Duplan, D.; Ball, D.

    2013-01-01

    Purpose: Stereotactic lung radiotherapy is complicated by tumor motion from patient respiration. Four-dimensional CT (4DCT) imaging is a motion compensation method used in treatment planning to generate a maximum intensity projection (MIP) internal target volume (ITV). Image guided radiotherapy during treatment may involve acquiring a volumetric cone-beam CT (CBCT) image and visually aligning the tumor to the planning 4DCT MIP ITV contour. Moving targets imaged with CBCT can appear blurred and currently there are no studies reporting on the effect that irregular breathing patterns have on CBCT volumes and their alignment to 4DCT MIP ITV contours. The objective of this work was therefore to image a phantom moving with irregular breathing patterns to determine whether any configurations resulted in errors in volume contouring or alignment. Methods: A Perspex thorax phantom was used to simulate a patient. Three wooden “lung” inserts with embedded Perspex “lesions” were moved up to 4 cm with computer-generated motion patterns, and up to 1 cm with patient-specific breathing patterns. The phantom was imaged on 4DCT and CBCT with the same acquisition settings used for stereotactic lung patients in the clinic and the volumes on all phantom images were contoured. This project assessed the volumes for qualitative and quantitative changes including volume, length of the volume, and errors in alignment between CBCT volumes and 4DCT MIP ITV contours. Results: When motion was introduced 4DCT and CBCT volumes were reduced by up to 20% and 30% and shortened by up to 7 and 11 mm, respectively, indicating that volume was being under-represented at the extremes of motion. Banding artifacts were present in 4DCT MIP images, while CBCT volumes were largely reduced in contrast. When variable amplitudes from patient traces were used and CBCT ITVs were compared to 4DCT MIP ITVs there was a distinct trend in reduced ITV with increasing amplitude that was not seen when compared to

  2. The effect of irregular breathing patterns on internal target volumes in four-dimensional CT and cone-beam CT images in the context of stereotactic lung radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Clements, N. [Department of Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne 3002, Australia and Department of Applied Sciences, RMIT University, Melbourne 3001 (Australia); Kron, T.; Roxby, P. [Department of Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne 3002 (Australia); Franich, R.; Dunn, L. [Department of Applied Sciences, RMIT University, Melbourne 3001 (Australia); Aarons, Y.; Chesson, B. [Department of Radiation Therapy, Peter MacCallum Cancer Centre, East Melbourne 3002 (Australia); Siva, S.; Duplan, D.; Ball, D. [Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne 3002 (Australia)

    2013-02-15

    Purpose: Stereotactic lung radiotherapy is complicated by tumor motion from patient respiration. Four-dimensional CT (4DCT) imaging is a motion compensation method used in treatment planning to generate a maximum intensity projection (MIP) internal target volume (ITV). Image guided radiotherapy during treatment may involve acquiring a volumetric cone-beam CT (CBCT) image and visually aligning the tumor to the planning 4DCT MIP ITV contour. Moving targets imaged with CBCT can appear blurred and currently there are no studies reporting on the effect that irregular breathing patterns have on CBCT volumes and their alignment to 4DCT MIP ITV contours. The objective of this work was therefore to image a phantom moving with irregular breathing patterns to determine whether any configurations resulted in errors in volume contouring or alignment. Methods: A Perspex thorax phantom was used to simulate a patient. Three wooden 'lung' inserts with embedded Perspex 'lesions' were moved up to 4 cm with computer-generated motion patterns, and up to 1 cm with patient-specific breathing patterns. The phantom was imaged on 4DCT and CBCT with the same acquisition settings used for stereotactic lung patients in the clinic and the volumes on all phantom images were contoured. This project assessed the volumes for qualitative and quantitative changes including volume, length of the volume, and errors in alignment between CBCT volumes and 4DCT MIP ITV contours. Results: When motion was introduced 4DCT and CBCT volumes were reduced by up to 20% and 30% and shortened by up to 7 and 11 mm, respectively, indicating that volume was being under-represented at the extremes of motion. Banding artifacts were present in 4DCT MIP images, while CBCT volumes were largely reduced in contrast. When variable amplitudes from patient traces were used and CBCT ITVs were compared to 4DCT MIP ITVs there was a distinct trend in reduced ITV with increasing amplitude that was not seen when

  3. Separate origins of the internal and external carotid arteries depicted on CT angiography: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kwang Ho [Dept. of horacic and Cardiovascular Surgery, Pusan National University Yangsan Hospital, Yangsan (Korea, Republic of); Beak, Hye Jin; Jung, Hyun Kyung [Dept. of Radiology, Haeundae Paik Hospital, Inje University College of Medicine, Busan (Korea, Republic of)

    2015-08-15

    Agenesis of the common carotid artery (CCA) is a rare congenital anomaly. We presented a rare case of unilateral congenital absence of the right CCA with separate origins of the ipsilateral internal and external carotid arteries from the brachiocephalic artery. Further, we reviewed the embryological mechanism and clinical importance of this anomaly.

  4. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... vessels. CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. CT is less sensitive to patient movement ...

  5. Computed Tomography (CT) -- Head

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    Full Text Available ... vessels. CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. CT is less sensitive to patient movement ...

  6. Abdominal and Pelvic CT

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    Full Text Available ... vessels. CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. CT is less sensitive to patient movement ...

  7. Abdominal and Pelvic CT

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    Full Text Available ... CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. CT ...

  8. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. CT ...

  9. Computed Tomography (CT) -- Head

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    Full Text Available ... CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. CT ...

  10. Relation of external surface to internal tumor motion studied with cine CT

    International Nuclear Information System (INIS)

    Chi, P.-C.M.; Balter, Peter; Luo Dershan; Mohan, Radhe; Pan Tinsu

    2006-01-01

    The accuracy of delivering gated-radiation therapy to lung tumors using an external respiratory surrogate relies on not only interfractional and intrafractional reproducibility, but also a strong correlation between external motion and internal tumor motion. The purpose of this work was to use the cine images acquired by four-dimensional computed tomography acquisition protocol to study the relation between external surface motion and internal tumor motion. The respiratory phase information of tumor motion and chest wall motion was measured on the cine images using a proposed region-of-interest (ROI) method and compared to measurement of an external respiratory monitoring device. On eight lung patient data sets, the phase shifts were measured between (1) the signal of a real-time positioning-management (RPM) respiratory monitoring device placed in the abdominal region and four surface locations on the chest wall (2) the RPM signal in the abdominal region and tumor motions, and (3) chest wall surface motions and tumor motions. Respiratory waveforms measured at different surface locations during the same respiratory cycle often varied and had significant phase shifts. Seven of the 8 patients showed the abdominal motion leading chest wall motion. The best correlation (smallest phase shift) was found between the abdominal motion and the superior-inferior (S-I) tumor motion. A wide range of phase shifts was observed between external surface motion and tumor anterior-posterior (A-P)/lateral motion. The result supported the placement of the RPM block in the abdominal region and suggested that during a gated therapy utilizing the RPM system, it is necessary to place the RPM block at the same location as it is during treatment simulation in order to reduce potential errors introduced by the position of the RPM block. Correlations between external motions and lateral/A-P tumor motions were inconclusive due to a combination of patient selection and the limitation of the ROI

  11. Comparison of three approaches to delineate internal gross tumor volume based on four-dimensional CT simulation images of non-small-cell lung cancer

    International Nuclear Information System (INIS)

    Li Fengxiang; Li Jianbin; Zhang Yingjie; Shang Dongping; Liu Tonghai; Tian Shiyu; Xu Min; Ma Changsheng

    2011-01-01

    Objective: To compare positional and volumetric differences of internal gross tumor volume (IGTV) delineated separately by three approaches based on four-dimensional CT (4DCT) for the primary tumor of non-small cell lung cancer (NLCLC). Methods: Twenty-one patients with NLCLC underwent big bore 4DCT simulation scan of the thorax. IGTVs of the primary tumor of NSCLC were delineated using three approaches as followed: (1) the gross tumor volume (GTV) on each of the ten the respiratory phases of the 4DCT image set were delineated and the ten GTV were fused to produce IGTV 10 ; (2) the GTV delineated separately based on 0% and 50% phase were fused to produce IGTV EI+EE ; (3) the visible tumor on the MIP images were delineated to produce IGTV MIP . The position of the target center, the volume of target, the degree of inclusion (DI) and the matching index (MI) were compared reciprocally between IGTV 10 , IGTV EI+EE and IGTV MIP . Results: Average differences between the position of the center of IGTVs on direction of x, y and z axes were less than 1 mm, with no statistically significant difference. The volume of IGTV 10 was larger than that of IGTV EI+EE , the difference was statistically significant (t=2.37, P=0.028); the volume of IGTV 10 was larger than that of IGTV MIP , but the difference was not statistically significant (t=1.95, P=0.065). The ratio of IGTV EI+EE with IGTV 10 , IGTV MIP with IGTV 10 were 0.85±0.08 and 0.92±0.11, respectively. DI of IGTV EI+EE in IGTV 10 , IGTV MIP in IGTV 10 were 84.78% ± 8. 95% and 88.47% ±9.04%. MI between IGTV 10 and IGTV EI+EE , IGTV 10 and IGTV MIP were 0.85 ±0.09, 0.86±0.09, respectively. Conclusions: The center displacement of the IGTVs delineated separately by the three different techniques based on 4DCT images are not obvious; IGTV EI+EE and IGTV MIP can not replace IGTV 10 , however, IGTV MIP is more close to IGTV 10 comparing to IGTV EI+EE . The ratio of GTV EI+EE with IGTV 10 is correlated to the tumor motion

  12. The prevalence of erosive osseous changes of the articular eminence in the temporomandibular joint in patients with mandibular prognathism without internal derangement. MR and helical CT findings

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Takafumi; Ito, Jusuke; Tanaka, Rei; Koyama, Jun-ichi; Kobayashi, Fukiko [Niigata Univ. (Japan). Graduate School of Medical and Dental Sciences

    2002-06-01

    The aim of this study was to assess the prevalence of erosive osseous changes of the articular eminence in the temporomandibular joint without internal derangement. Sixty joints of 30 consecutive patients with mandibular prognathism were evaluated with both MR imaging and helical CT. On MPR images obtained with helical CT, erosive osseous changes of the articular eminence were observed in 18 joints (30%) of 13 patients. None of the joints studied demonstrated an osseous change in the mandibular condyle. MR imaging failed to detect erosive osseous changes of the articular eminence in all of the joints studied. In conclusion, MPR images obtained with helical CT were of value to detect erosive osseous changes of the articular eminence. (author)

  13. Transretroperitoneal CT-guided Embolization of Growing Internal Iliac Artery Aneurysm after Repair of Abdominal Aortic Aneurysm: A Transretroperitoneal Approach with Intramuscular Lidocaine Injection Technique

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joon Young, E-mail: pjy1331@hanmail.net; Kim, Shin Jung, E-mail: witdd2@hanmail.net; Kim, Hyoung Ook, E-mail: chaos821209@hanmail.net [Chonnam National University Hospital, Department of Radiology (Korea, Republic of); Kim, Yong Tae, E-mail: mono-111@hanmail.net [Chonnam National University Hwasun Hospital, Department of Radiology (Korea, Republic of); Lim, Nam Yeol, E-mail: apleseed@hanmail.net; Kim, Jae Kyu, E-mail: kjkrad@jnu.ac.kr [Chonnam National University Hospital, Department of Radiology (Korea, Republic of); Chung, Sang Young, E-mail: sycpvts@jnu.ac.kr; Choi, Soo Jin Na, E-mail: choisjn@jnu.ac.kr; Lee, Ho Kyun, E-mail: mhaha@hanmail.net [Chonnam National University Hospital, Department of Surgery (Korea, Republic of)

    2015-02-15

    This study was designed to evaluate the efficacy and safety of CT-guided embolization of internal iliac artery aneurysm (IIAA) after repair of abdominal aortic aneurysm by transretroperitoneal approach using the lidocaine injection technique to iliacus muscle, making window for safe needle path for three patients for whom CT-guided embolization of IIAA was performed by transretroperitoneal approach with intramuscular lidocaine injection technique. Transretroperitoneal access to the IIAA was successful in all three patients. In all three patients, the IIAA was first embolized using microcoils. The aneurysmal sac was then embolized with glue and coils without complication. With a mean follow-up of 7 months, the volume of the IIAAs remained stable without residual endoleaks. Transretroperitoneal CT-guided embolization of IIAA using intramuscular lidocaine injection technique is effective, safe, and results in good outcome.

  14. Analyses of the internal structure of the oscillating vibro-packed fuels by the micro focus X-rays CT method

    International Nuclear Information System (INIS)

    Mizuta, Yasutoshi

    2003-02-01

    The purpose of this study is to support the development of vibro-packed fuel technology at Japan Nuclear Cycle Development Institute. 3-dimensional (3-D) data was built from the multi-cross sectional images obtained by the micro focus X-rays CT method in the vibro-packed fuel models. The structural analyses were carried out about the obtained 3-D CT images. The packing-rate distribution and the density distribution were measured as well as the number distribution of particles, etc. Consequently, it is obtained that vibrate conditions and a vibrating state have strong correlation, and it is also shown that the 3-D analyses of the internal structure by the micro focus X-rays CT method are effective in performance evaluation of vibro-packed fuels. (author)

  15. The prevalence of erosive osseous changes of the articular eminence in the temporomandibular joint in patients with mandibular prognathism without internal derangement. MR and helical CT findings

    International Nuclear Information System (INIS)

    Hayashi, Takafumi; Ito, Jusuke; Tanaka, Rei; Koyama, Jun-ichi; Kobayashi, Fukiko

    2002-01-01

    The aim of this study was to assess the prevalence of erosive osseous changes of the articular eminence in the temporomandibular joint without internal derangement. Sixty joints of 30 consecutive patients with mandibular prognathism were evaluated with both MR imaging and helical CT. On MPR images obtained with helical CT, erosive osseous changes of the articular eminence were observed in 18 joints (30%) of 13 patients. None of the joints studied demonstrated an osseous change in the mandibular condyle. MR imaging failed to detect erosive osseous changes of the articular eminence in all of the joints studied. In conclusion, MPR images obtained with helical CT were of value to detect erosive osseous changes of the articular eminence. (author)

  16. Defining internal target volume (ITV) for hepatocellular carcinoma using four-dimensional CT

    International Nuclear Information System (INIS)

    X, Mian; Liu Mengzhong; Deng Xiaowu; Zhang Li; Huang Xiaoyan; Liu Hui; Li Qiaoqiao; Hu Yonghong; Cai Ling; Cui Nianji

    2007-01-01

    Background and purpose: To define individualized internal target volume (ITV) for hepatocellular carcinoma using four-dimensional computed tomography (4DCT). Materials and methods: Gross tumor volumes (GTVs) and clinical target volumes (CTVs) were contoured on all 10 respiratory phases of 4DCT scans in 10 patients with hepatocellular carcinoma. The 3D and 4D treatment plans were performed for each patient using two different planning target volumes (PTVs): (1) PTV 3D was derived from a single CTV plus conventional margins; (2) PTV 4D was derived from ITV 4D , which encompassed all 10 CTVs plus setup margins (SMs). The volumes of PTVs and dose distribution were compared between the two plans. Results: The average PTV volume of the 4D plans (328.4 ± 152.2 cm 3 ) was less than 3D plans (407.0 ± 165.6 cm 3 ). The 4D plans spared more surrounding normal tissues than 3D plans, especially normal liver. Compared with 3D plans, the mean dose to normal liver (MDTNL) decreased from 22.7 to 20.3 Gy. Without increasing the normal tissue complication probability (NTCP), the 4D plans allowed for increasing the calculated dose from 50.4 ± 1.3 to 54.2 ± 2.6 Gy, an average increase of 7.5% (range 4.0-16.0%). Conclusions: The conventional 3D plans can result in geometric miss and include excess normal tissues. The 4DCT-based plans can reduce the target volumes to spare more normal tissues and allow dose escalation compared with 3D plans

  17. Extent of hypoattenuation on CT angiography source images in basilar artery occlusion: prognostic value in the Basilar Artery International Cooperation Study.

    Science.gov (United States)

    Puetz, Volker; Khomenko, Andrei; Hill, Michael D; Dzialowski, Imanuel; Michel, Patrik; Weimar, Christian; Wijman, Christine A C; Mattle, Heinrich P; Engelter, Stefan T; Muir, Keith W; Pfefferkorn, Thomas; Tanne, David; Szabo, Kristina; Kappelle, L Jaap; Algra, Ale; von Kummer, Ruediger; Demchuk, Andrew M; Schonewille, Wouter J

    2011-12-01

    The posterior circulation Acute Stroke Prognosis Early CT Score (pc-ASPECTS) quantifies the extent of early ischemic changes in the posterior circulation with a 10-point grading system. We hypothesized that pc-ASPECTS applied to CT angiography source images predicts functional outcome of patients in the Basilar Artery International Cooperation Study (BASICS). BASICS was a prospective, observational registry of consecutive patients with acute symptomatic basilar artery occlusion. Functional outcome was assessed at 1 month. We applied pc-ASPECTS to CT angiography source images of patients with CT angiography for confirmation of basilar artery occlusion. We calculated unadjusted and adjusted risk ratios (RRs) of pc-ASPECTS dichotomized at ≥8 versus <8. Primary outcome measure was favorable outcome (modified Rankin Scale scores 0-3). Secondary outcome measures were mortality and functional independence (modified Rankin Scale scores 0-2). Of 158 patients included, 78 patients had a CT angiography source images pc-ASPECTS≥8. Patients with a pc-ASPECTS≥8 more often had a favorable outcome than patients with a pc-ASPECTS<8 (crude RR, 1.7; 95% CI, 0.98-3.0). After adjustment for age, baseline National Institutes of Health Stroke Scale score, and thrombolysis, pc-ASPECTS≥8 was not related to favorable outcome (RR, 1.3; 95% CI, 0.8-2.2), but it was related to reduced mortality (RR, 0.7; 95% CI, 0.5-0.98) and functional independence (RR, 2.0; 95% CI, 1.1-3.8). In post hoc analysis, pc-ASPECTS dichotomized at ≥6 versus <6 predicted a favorable outcome (adjusted RR, 3.1; 95% CI, 1.2-7.5). pc-ASPECTS on CT angiography source images independently predicted death and functional independence at 1 month in the CT angiography subgroup of patients in the BASICS registry.

  18. Radiolucencies and cavitation in bronchioloalveolar carcinoma: CT-pathologic correlation

    International Nuclear Information System (INIS)

    Gaeta, M.; Bartiromo, G.; Caruso, R.; Blandino, A.; Scribano, E.; Pandolfo, I.

    1999-01-01

    Bronchioloalveolar carcinoma (BAC) is a polymorphic lung cancer the incidence of which is rising. The presence of intratumoral radiolucencies is an important feature of bronchioloalveolar carcinoma.The aim of this study was to present pictorially the spectrum of intratumoral radiolucencies visible in BAC. In 57 BACs studied with thin-slice CT, we identified six types of radiolucencies: (a) patent intratumoral bronchioles (air bronchiologram); (b) pseudocavitations; (c) cavitation; (d) serpentine radiolucencies; (e) internal alveologram; and (f) multiple cystic lesions. (orig.) (orig.)

  19. Development and application of a tomographic model from CT images for calculating internal dose to a pregnant woman

    International Nuclear Information System (INIS)

    Shi Chengyu

    2004-01-01

    Assessment of radiation dose and possible risk to a pregnant woman and her fetus is an important task in radiation protection. Although stylized models for male and female patients of different ages have been developed, tomographic models for pregnant women have not been developed to date. This dissertation presents an effort to construct a partial-body model of a pregnant woman from a set of CT images. The patient was 30-weeks pregnant, and the CT scan covered the portion of the body from above liver to below pubic symphysis in 70 slices, each 7 mm thick. The image resolution was 512x512 pixels in a 48 cmx48 cm field. The images were carefully segmented to identify 34 organs and tissues. It has been found that the masses are different from the Reference Woman. The characteristics of the resulting model are discussed and compared with one existing stylized mathematical model for pregnant women. Based on this tomographic model, a Monte Carlo code, EGS4-VLSI, was used to derive specific absorbed fractions. Monoenergetic and isotropic photon and electron emitters distributed in different source organs were assumed and the energies ranged from 10 keV to 4 MeV for photons and from 100 keV to 4 MeV for electrons. The results for high energy (>50 keV) photons showed general agreement with previous studies, however, the results for lower energy (<50 keV) photons showed differences of up to several hundred percent for some source and target organs. For electron results, several tens of percent differences were found. Those differences can be explained by mass differences and the relative geometry differences between source and target organs. In summary, the stylized models for pregnant women are satisfactory for a very large size patient for most of the photon energies (between 50 keV and 4 MeV). However, a tomographic model has to be used to obtain acceptable dose assessments for electrons. The newly calculated SAF data set can provide the nuclear medicine dosimetry field

  20. Abdominal and Pelvic CT

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    Full Text Available ... emergency cases, it can reveal internal injuries and bleeding quickly enough to help save lives. Tell your ... emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has ...

  1. Computed Tomography (CT) -- Head

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    Full Text Available ... brain cancer. In emergency cases, it can reveal internal injuries and bleeding quickly enough to help save ... to a CD or DVD. CT images of internal organs, bones, soft tissue and blood vessels provide ...

  2. Agenesis of the internal carotid artery with a trans-sellar anastomosis: CT and MRI findings in late-onset congenital hypopituitarism

    International Nuclear Information System (INIS)

    Mellado, J.M.; Merino, X.; Ramos, A.; Salvado, E.; Sauri, A.

    2001-01-01

    A 29-year-old woman with a history of hypothyroidism since early childhood developed hypopituitarism. CT and MRI revealed anterior pituitary hypoplasia, an ectopic posterior lobe, a Chiari I malformation and agenesis of the right internal carotid artery with a trans-sellar anastomosis. This constellation of findings constitutes a previously unreported association in congenital hypopituitarism of late onset. The usefulness of imaging modalities and the pathogenic implications are also discussed. (orig.)

  3. CT of splenic trauma

    International Nuclear Information System (INIS)

    Griffiths, B.G.; Federle, M.P.; Minagi, H.; Jeffrey, R.B.

    1986-01-01

    Fifty-five consecutive cases of surgically proved splenic injuries were evaluated by CT. CT correctly identified 54 splenic injuries, with one false-negative and three false-positive studies. In the single false-negative study and in two of the three false-positive studies, CT correctly indicated the presence of a large hemoperitoneum and other abdominal visceral lacerations and so correctly indicated the need for surgery. Of the 55 proved cases of splenic injury, CT revealed hemoperitoneum in 54 (99%), perisplenic clot in 47 (85%), splenic laceration in 39 (71%), and subcapsular hematoma in 13 (24%). Perisplenic clot can be distinguished from lysed blood in the peritoneal cavity and is a sensitive and specific sign of splenic trauma, even in the absence of visible splenic laceration. The authors conclude that CT is highly reliable means of evaluating splenic trauma

  4. Comparison of internal target volumes defined on 3-dimensional, 4-dimensonal, and cone-beam CT images of non-small-cell lung cancer

    Directory of Open Access Journals (Sweden)

    Li F

    2016-11-01

    Full Text Available Fengxiang Li,1 Jianbin Li,1 Zhifang Ma,1 Yingjie Zhang,1 Jun Xing,1 Huanpeng Qi,1 Dongping Shang21Department of Radiation Oncology, 2Department of Big Bore CT Room, Shandong Cancer Hospital Affiliated to Shandong University, Shandong Academy of Medical Sciences, Jinan, Shandong, People’s Republic of ChinaPurpose: The purpose of this study was to compare the positional and volumetric differences of internal target volumes defined on three-dimensional computed tomography (3DCT, four-dimensional CT (4DCT, and cone-beam CT (CBCT images of non-small-cell lung cancer (NSCLC. Materials and methods: Thirty-one patients with NSCLC sequentially underwent 3DCT and 4DCT simulation scans of the thorax during free breathing. The first CBCT was performed and registered to the planning CT using the bony anatomy registration during radiotherapy. The gross tumor volumes were contoured on the basis of 3DCT, maximum intensity projection (MIP of 4DCT, and CBCT. CTV3D (clinical target volume, internal target volumes, ITVMIP and ITVCBCT, were defined with a 7 mm margin accounting for microscopic disease. ITV10 mm and ITV5 mm were defined on the basis of CTV3D: ITV10 mm with a 5 mm margin in left–right (LR, anterior–posterior (AP directions and 10 mm in cranial–caudal (CC direction; ITV5 mm with an isotropic internal margin (IM of 5 mm. The differences in the position, size, Dice’s similarity coefficient (DSC and inclusion relation of different volumes were evaluated.Results: The median size ratios of ITV10 mm, ITV5 mm, and ITVMIP to ITVCBCT were 2.33, 1.88, and 1.03, respectively, for tumors in the upper lobe and 2.13, 1.76, and 1.1, respectively, for tumors in the middle-lower lobe. The median DSCs of ITV10 mm, ITV5 mm, ITVMIP, and ITVCBCT were 0.6, 0.66, and 0.83 for all patients. The median percentages of ITVCBCT not included in ITV10 mm, ITV5 mm, and ITVMIP were 0.1%, 1.63%, and 15.21%, respectively, while the median percentages of ITV10 mm, ITV5 mm

  5. Abdominal and Pelvic CT

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    Full Text Available ... CD or DVD. CT images of internal organs, bones, soft tissue and blood vessels provide greater detail than traditional ... advantage of CT is its ability to image bone, soft tissue and blood vessels all at the same time. ...

  6. Computed Tomography (CT) -- Head

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    Full Text Available ... CD or DVD. CT images of internal organs, bones, soft tissue and blood vessels provide greater detail than traditional ... advantage of CT is its ability to image bone, soft tissue and blood vessels all at the same time. ...

  7. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... CD or DVD. CT images of internal organs, bones, soft tissue and blood vessels provide greater detail than traditional ... advantage of CT is its ability to image bone, soft tissue and blood vessels all at the same time. ...

  8. A comparative study of perfusion CT and 99mTc-Hmpao spect measurement to assess cerebrovascular reserve capacity in patients with internal carotid artery occlusion

    Directory of Open Access Journals (Sweden)

    Eicker S

    2011-11-01

    Full Text Available Abstract Background and purpose Patients with internal carotid artery (ICA occlusion can demonstrate impaired cerebral vascular reserve (CVR. The detection of CVR using single photon emission CT (SPECT is nowadays widely accepted as a predictor in the diagnostic pathway in patients considered for cerebral revascularization. Recently perfusion CT (PCT gained widely acceptance in stroke imaging The present study was aimed at comparing the results of perfusion CT (PCT and 99mTc-HMPAO SPECT with acetazolamide challenge in patients with ICA occlusion. Methods 13 patients were included in the prospective evaluation. Both PCT and 99mTc-HMPAO SPECT were performed before and after the administration of acetazolamide. In detail, regional cerebral blood flow (rCBF, regional cerebral blood volume (rCBV, adapted time to peak (Tmax and mean transit times (MTT were compared with SPECT data. Results 99mTc-HMPAO SPECT demonstrated an impairment of CVR in six patients. A preserved CVR was present in seven patients. All patients with impaired CVR proven by SPECT had a delayed MTT (mean +2.98 s and a delayed Tmax (mean + 5.9 s, (both p Conclusion The prospective study demonstrated a highly significant correlation of perfusion parameters as' detected by 99mTc-HMPAO SPECT and the Tmax as detected by PCT in patients with ICA occlusion. Therefore this easy-to-perform technique seems to be an adequate method for the evaluation of cerebral perfusion in patients with ICA occlusion.

  9. An evaluation of an automated 4D-CT contour propagation tool to define an internal gross tumour volume for lung cancer radiotherapy

    International Nuclear Information System (INIS)

    Gaede, Stewart; Olsthoorn, Jason; Louie, Alexander V.; Palma, David; Yu, Edward; Yaremko, Brian; Ahmad, Belal; Chen, Jeff; Bzdusek, Karl; Rodrigues, George

    2011-01-01

    Background and purpose: To evaluate an automated 4D-CT contouring propagation tool by its impact on the inter- and intra-physician variability in lung tumour delineation. Materials and methods: In a previous study, six radiation oncologists contoured the gross tumour volume (GTV) and nodes on 10 phases of the 4D-CT dataset of 10 lung cancer patients to examine the intra- and inter-physician variability. In this study, a model-based deformable image registration algorithm was used to propagate the GTV and nodes on each phase of the same 4D-CT datasets. A blind review of the contours was performed by each physician and edited. Inter- and intra-physician variability for both the manual and automated methods was assessed by calculating the centroid motion of the GTV using the Pearson correlation coefficient and the variability in the internal gross tumour volume (IGTV) overlap using the Dice similarity coefficient (DSC). Results: The time for manual delineation was (42.7 ± 18.6) min versus (17.7 ± 5.4) min when the propagation tool was used. A significant improvement in the mean Pearson correlation coefficient was also observed. There was a significant decrease in mean DSC in only 1 out of 10 primary IGTVs and 2 out of 10 nodal IGTVs. Intra-physician variability was not significantly impacted (DSC > 0.742). Conclusions: Automated 4D-CT propagation tools can significantly decrease the IGTV delineation time without significantly decreasing the inter- and intra-physician variability.

  10. Patient position matching between SPECT and CT

    International Nuclear Information System (INIS)

    Eubig, C.; Lodhi, L.M.; Trueblood, J.H.; Kingsbury, T.; Burke, G.; Flickenger, F.

    1990-01-01

    Since the authors had previously developed an ability for accurate repositioning of patients by means of video imaging of their external features, it was their purpose to determine if separate video systems placed in SPECT and CT rooms could be positioned and a calibration procedure for each modality developed to assure easy identification and acquisition of corresponding congruent axial image sections through the patient. A video frame grabber is used to acquire an image of the patient in one room and superimpose it on a similar image of the patient in the other room. A radioactive ruler visible at CT images obtained with a gamma camera computer, and a CT scout image are used to adjust the initial relative position of the video cameras and calibrate the acquisition parameters of both systems. The success of this alignment procedure was tested with a body phantom. The body phantom studies indicate that this method of positioning the patient and acquiring corresponding aligned CT and SPECT axial sections can be successful where internal organ shift between the acquisitions is minimal. This should lead to a reduction of the time and computer resources necessary to fuse or superimpose images of corresponding patient sections acquired with different modalities

  11. Abdominal and Pelvic CT

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    Full Text Available ... often used to determine the cause of unexplained pain. CT scanning is fast, painless, noninvasive and accurate. ... help diagnose the cause of abdominal or pelvic pain and diseases of the internal organs, small bowel ...

  12. Computed Tomography (CT) -- Head

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    Full Text Available ... CD or DVD. CT images of internal organs, bones, soft tissue and blood vessels provide greater detail ... is also performed to: evaluate the extent of bone and soft tissue damage in patients with facial ...

  13. Abdominal and Pelvic CT

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    Full Text Available ... CD or DVD. CT images of internal organs, bones, soft tissue and blood vessels provide greater detail ... image on a special electronic image recording plate. Bones appear white on the x-ray; soft tissue, ...

  14. Abdominal and Pelvic CT

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    Full Text Available ... the Abdomen/Pelvis? Computed tomography, more commonly known as a CT or CAT scan, is a diagnostic ... the internal organs, small bowel and colon, such as: infections such as appendicitis , pyelonephritis or infected fluid ...

  15. Computed Tomography (CT) -- Head

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    Full Text Available ... images can be viewed on a computer monitor, printed on film or transferred to a CD or DVD. CT images of internal organs, bones, soft tissue and blood vessels provide greater detail ...

  16. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... images can be viewed on a computer monitor, printed on film or transferred to a CD or DVD. CT images of internal organs, bones, soft tissue and blood vessels provide greater detail ...

  17. Abdominal and Pelvic CT

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    Full Text Available ... images can be viewed on a computer monitor, printed on film or transferred to a CD or DVD. CT images of internal organs, bones, soft tissue and blood vessels provide greater detail ...

  18. Computed Tomography (CT) -- Head

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    Full Text Available ... therapy for brain cancer. In emergency cases, it can reveal internal injuries and bleeding quickly enough to ... cross-sectional images generated during a CT scan can be reformatted in multiple planes, and can even ...

  19. Abdominal and Pelvic CT

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    Full Text Available ... painless, noninvasive and accurate. In emergency cases, it can reveal internal injuries and bleeding quickly enough to ... cross-sectional images generated during a CT scan can be reformatted in multiple planes, and can even ...

  20. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... vessels. CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. CT is less sensitive to patient movement ...

  1. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. CT ...

  2. Quantitative Assessment of Degenerative Cartilage and Subchondral Bony Lesions in a Preserved Cadaveric Knee: Propagation-Based Phase-Contrast CT Versus Conventional MRI and CT.

    Science.gov (United States)

    Geith, Tobias; Brun, Emmanuel; Mittone, Alberto; Gasilov, Sergei; Weber, Loriane; Adam-Neumair, Silvia; Bravin, Alberto; Reiser, Maximilian; Coan, Paola; Horng, Annie

    2018-04-09

    The aim of this study was to quantitatively assess hyaline cartilage and subchondral bone conditions in a fully preserved cadaveric human knee joint using high-resolution x-ray propagation-based phase-contrast imaging (PBI) CT and to compare the performance of the new technique with conventional CT and MRI. A cadaveric human knee was examined using an x-ray beam of 60 keV, a detector with a 90-mm 2 FOV, and a pixel size of 46 × 46 μm 2 . PBI CT images were reconstructed with both the filtered back projection algorithm and the equally sloped tomography method. Conventional 3-T MRI and CT were also performed. Measurements of cartilage thickness, cartilage lesions, International Cartilage Repair Society scoring, and detection of subchondral bone changes were evaluated. Visual inspection of the specimen akin to arthroscopy was conducted and served as a standard of reference for lesion detection. Loss of cartilage height was visible on PBI CT and MRI. Quantification of cartilage thickness showed a strong correlation between the two modalities. Cartilage lesions appeared darker than the adjacent cartilage on PBI CT. PBI CT showed similar agreement to MRI for depicting cartilage substance defects or lesions compared with the visual inspection. The assessment of subchondral bone cysts showed moderate to strong agreement between PBI CT and CT. In contrast to the standard clinical methods of MRI and CT, PBI CT is able to simultaneously depict cartilage and bony changes at high resolution. Though still an experimental technique, PBI CT is a promising high-resolution imaging method to evaluate comprehensive changes of osteoarthritic disease in a clinical setting.

  3. Prognostic Value of FDG-PET, Based on the Revised Response Criteria, in Patients with Malignant Lymphoma: A Comparison with CT/MRI Evaluations, Based on the International Working Group/ Cotswolds Meeting Criteria

    Directory of Open Access Journals (Sweden)

    Kayako Isohashi

    2015-07-01

    Full Text Available Objective(s: Post-treatment evaluations by CT/MRI (based on the International Working Group/ Cotswolds meeting guidelines and PET (based on Revised Response Criteria, were examined in terms of progression-free survival (PFS in patients with malignant lymphoma (ML. Methods: 79 patients, undergoing CT/MRI for the examination of suspected lesions and whole-body PET/CT before and after therapy, were included in the study during April 2007-January 2013. The relationship between post-treatment evaluations (CT/MRI and PET and PFS during the follow-up period was examined, using Kaplan-Meier survival analysis. The patients were grouped according to the histological type into Hodgkin’s lymphoma (HL, diffuse large B-cell lymphoma (DLBCL, and other histological types. The association between post-treatment evaluations (PET or PET combined with CT/ MRI and PFS was examined separately. Moreover, the relationship between disease recurrence and serum soluble interleukin-2 receptor, lactic dehydrogenase, and C-reactive protein levels was evaluated before and after the treatment. Results: Patients with incomplete remission on both CT/MRI and PET had a significantly shorter PFS, compared to patients with complete remission on both CT/MRI and PET and those exhibiting incomplete remission on CT/MRI and complete remission on PET (P

  4. Value of MR and CT Imaging for Assessment of Internal Carotid Artery Encasement in Head and Neck Squamous Cell Carcinoma

    Directory of Open Access Journals (Sweden)

    W. L. Lodder

    2013-01-01

    Full Text Available Objective. This study was conducted to assess the value of CT and MR imaging in the preoperative evaluation of ICA encasement. Methods. Based upon three patient groups this study was performed. Retrospective analysis of 260 neck dissection reports from 2001 to 2010 was performed to determine unexpected peroperative-diagnosed encasement. Two experienced head and neck radiologists reviewed 12 scans for encasement. Results. In four out of 260 (1.5% patients undergoing neck dissection, preoperative imaging was false negative as there was peroperative encasement of the ICA. Of 380 patients undergoing preoperative imaging, the radiologist reported encasement of the ICA in 25 cases. In 342 cases no encasement was described, 125 of these underwent neck dissection, and 2 had encasement peroperatively. The interobserver variation kappa varied from 0.273 to 1 for the different characteristics studied. Conclusion. These retrospectively studied cohorts demonstrate that preoperative assessment of encasement of the ICA using MRI and/or CT was of value in evaluation of ICA encasement and therefore contributively in selecting operable patients (without ICA encasement, since in only 1.5% encasement was missed. However, observer variation affects the reliability of this feature.

  5. Visibility and Haze

    Science.gov (United States)

    Haze forms when sunlight encounters particle pollution. It reduces visibility in cities and scenic areas. This web area provides regulatory information and progress towards improving visibility through EPA’s regional haze program.

  6. Visible Human Project

    Science.gov (United States)

    ... cryosections are associated with anatomical terminology. AnatLine : A prototype system consisting of an anatomical image database and ... further information is available Publications VHJOE: Visible Human Journal of Endoscopy. NLM's Current Bibliographies in Medicine, Visible ...

  7. Visibly Pushdown Automata

    DEFF Research Database (Denmark)

    Srba, Jiri

    2006-01-01

    We investigate the possibility of (bi)simulation-like preorder/equivalence checking on the class of visibly pushdown automata and its natural subclasses visibly BPA (Basic Process Algebra) and visibly one-counter automata. We describe generic methods for proving complexity upper and lower bounds...... for a number of studied preorders and equivalences like simulation, completed simulation, ready simulation, 2-nested simulation preorders/equivalences and bisimulation equivalence. Our main results are that all the mentioned equivalences and preorders are EXPTIME-complete on visibly pushdown automata, PSPACE......-complete on visibly one-counter automata and P-complete on visibly BPA. Our PSPACE lower bound for visibly one-counter automata improves also the previously known DP-hardness results for ordinary one-counter automata and one-counter nets. Finally, we study regularity checking problems for visibly pushdown automata...

  8. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... create detailed images of your child’s internal organs, bones, soft tissues and blood vessels. It may be ... CD or DVD. CT images of internal organs, bones, soft tissue and blood vessels provide greater detail ...

  9. Prognostic Value of FDG-PET, Based on the Revised Response Criteria, in Patients with Malignant Lymphoma: A Comparison with CT/MRI Evaluations, Based on the International Working Group/Cotswolds Meeting Criteria

    International Nuclear Information System (INIS)

    Isohashi, Kayako; Tatsumi, Mitsuaki; Kato, Hiroki; Fukushima, Kentaro; Maeda, Tetsuo; Watabe, Tadashi; Shimosegawa, Eku; Kanakura, Yuzuru; Hatazawa, Jun

    2015-01-01

    Post-treatment evaluations by CT/MRI (based on the International Working Group/Cotswolds meeting guidelines) and PET (based on Revised Response Criteria), were examined in terms of progression-free survival (PFS) in patients with malignant lymphoma (ML). 79 patients, undergoing CT/MRI for the examination of suspected lesions and whole-body PET/CT before and after therapy, were included in the study during April 2007-January 2013. The relationship between post-treatment evaluations (CT/MRI and PET) and PFS during the follow-up period was examined, using Kaplan-Meier survival analysis. The patients were grouped according to the histological type into Hodgkin’s lymphoma (HL), diffuse large B-cell lymphoma (DLBCL), and other histological types. The association between post-treatment evaluations (PET or PET combined with CT/MRI) and PFS was examined separately. Moreover, the relationship between disease recurrence and serum soluble interleukin-2 receptor, lactic dehydrogenase, and C-reactive protein levels was evaluated before and after the treatment. Patients with incomplete remission on both CT/MRI and PET had a significantly shorter PFS, compared to patients with complete remission on both CT/MRI and PET and those exhibiting incomplete remission on CT/MRI and complete remission on PET (P<0.001). Post-treatment PET evaluations were strongly correlated with patient outcomes in cases with HL or DLBCL (P<0.01) and other histological types (P<0.001). In patients with HL or DLBCL, incomplete remission on both CT/MRI and PET was associated with a significantly shorter PFS, compared to patients with complete remission on both CT/MRI and PET (P<0.05) and those showing incomplete remission on CT/MRI and complete remission on PET (P<0.01). In patients with other histological types, incomplete remission on both CT/MRI and PET was associated with a significantly shorter PFS, compared to cases with complete remission on both CT/MRI and PET (P<0.001). None of the serum parameters

  10. Balloon test occlusion of the internal carotid artery with stable xenon/CT cerebral blood flow imaging

    International Nuclear Information System (INIS)

    Erba, S.M.; Horton, J.A.; Latchaw, R.E.; Yonas, H.; Sekhar, L.; Schramm, V.; Pentheny, S.

    1988-01-01

    We describe a technique to predict preoperatively the safety of permanently occluding an internal carotid artery. The method was performed by imaging stable xenon cerebral blood flow (CBF) with the internal carotid artery both open and temporarily occluded with a nondetachable balloon on a double lumen Swan-Ganz catheter. Patients were those in whom we planned to sacrifice the internal carotid artery (those with giant or inaccessible aneurysms) or those in whom such a sacrifice was at least likely (those with skull base tumors). Patients were divided into three groups on the basis of a comparison of occluded and nonoccluded CBF values. Group-I patients had no significant change in CBF with internal carotid artery occlusion; group-II patients showed a symmetric decrease in CBF; and group-III patients had an asymmetric decrease in CBF, always greater on the occluded side. A fourth group clinically failed to tolerate even brief carotid occlusion. The internal carotid artery in one patients from group III was sacrificed at surgery: the size and shape of his postoperative infarct corresponded almost exactly to the area of asymmetrically decreased CBF on his occluded study. The data suggest that if surgery is likely to result in permanent occlusion of the internal carotid artery, then patients who are at risk for delayed neurologic injury due to a compromised cerebral blood flow should have arterial bypass grafts before such surgery is performed

  11. Morphological changes of the internal structure of maxillae with tooth loss. Three-dimensional and mechanical analysis using micro-CT and finite element method

    International Nuclear Information System (INIS)

    Usami, Akinobu; Hara, Toshihiro; Ide, Yoshinobu

    2003-01-01

    The purpose of this study was to analyze the morphological and mechanical properties of the internal structures of maxillae at the molar region using a micro-CT system. Ten dentulous and edentulous maxillae were employed in this study. Images and angle information from all materials were taken by a micro-CT and 100 x 100 x 100 voxels were extracted from the fixed buccal and palatal molar regions in each material for three-dimensional morphological analysis of the internal structure. The bone volume fraction, trabecular thickness, trabecular separation and trabecular number were calculated. To analyze mechanical properties all voxels were converted to micro finite element models with element size of 33 x 33 x 33 μm 3 and maximal stiffness, axial stiffness and angle between the stiffest direction of trabecular and the axial loading direction (angleα) were determined using micro finite element method. In the result, the morphological changes including decrease of bone volume fraction, trabecular thickness and increase of trabecular separation were evident with tooth loss, although trabecular number was not changed. Mechanically, maximal stiffness was decreased with tooth loss at buccal region. However, the axial stiffness at buccal region was larger and the angleα was distributed widely in each edentulous maxilla, comparing to the same region of dentulous maxilla. These findings suggest that trabecular bone become thinner in both buccal and palatal regions, consequently maximal stiffness at buccal region become smaller with tooth loss. On the other hand, axial stiffness at the buccal region in edentulous was larger than one in dentulous. It seems to be caused by the change of the angleα. (author)

  12. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... to help detect diseases of the small bowel, colon and other internal organs and is often used to determine the cause of unexplained pain. CT scanning is fast, painless, noninvasive and accurate. In emergency cases, it can reveal internal injuries and bleeding quickly enough to help save lives. ...

  13. Internal disc derangement in patients with low back pain: correlation of MR imaging and provocative discography and CT discography

    International Nuclear Information System (INIS)

    Chung, Hye Won; Cheon, Jung Eun; Hong, Sung Hwan; Kang, Heung Sik; Lee, Ji Ho; Oh, Joo Han; Jeon, Pyoung

    2004-01-01

    The aim of this study was to correlate the MR imaging abnormalities of the lumbar intervertebral discs, with emphasis being placed on the high intensity zone (HIZ) with the use of discography for pain provocation and disc morphologic evaluation of the disc. Consecutive patients with low back pain unresponsive to conservative treatment, and who were being considered for spinal fusion had MRI performed, and this was followed by lumbar discography. The MR imaging, discography and CT discography (CTD) were evaluated for all of the 19 patients. Forty-three lumbar discs in 19 patients were included in this study. The findings of MR and CTD images were evaluated retrospectively with the professional opinion and agreement of two radiologists. MR images were assessed for the presence or absence of decreased T2-wighted signal intensity, decreased disc height, annular bulging, HIZ on T2-weighted images and disc herniation. The results of pain provocation were graded as 0, nonconcordant pain; 1, definite pain, but only as part of the symptom complex; 2, concordant pain. The morphology of CTD was analyzed for presence or absence of disc degeneration, radial tearing and extravasation of the contrast agent. The presence of radial tearing was defined as contrast extension to the outer third of the annulus. The prevalence of all MR abnormalities was calculated, and the data were compared with disc morphologic characteristics and the pain response on provocative discography. We used the chi-square test to analyze the results. Grade 1 and 2 discogenic pain was observed in 8 (19%) and 12 disc levels (28%), respectively. All of the seven non-degenerated discs on MR had no pain response. The decreased SI on T2-weighted image, annular bulging and HIZ were significantly correlated with discogenic pain. Extravasation of contrast media had good correlation with annular bulging and disc herniation on MRI. Radial tearing on CT discography correlated significantly with HIZ. The HIZ was

  14. Radiolucencies and cavitation in bronchioloalveolar carcinoma: CT-pathologic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Gaeta, M.; Bartiromo, G. [Service of Diagnostic Imaging, Piemonte Hospital, Messina (Italy); Caruso, R. [Institute of Pathology, University of Messina (Italy); Blandino, A.; Scribano, E.; Pandolfo, I. [Institute of Radiologic Sciences, University of Messina (Italy)

    1999-02-01

    Bronchioloalveolar carcinoma (BAC) is a polymorphic lung cancer the incidence of which is rising. The presence of intratumoral radiolucencies is an important feature of bronchioloalveolar carcinoma.The aim of this study was to present pictorially the spectrum of intratumoral radiolucencies visible in BAC. In 57 BACs studied with thin-slice CT, we identified six types of radiolucencies: (a) patent intratumoral bronchioles (air bronchiologram); (b) pseudocavitations; (c) cavitation; (d) serpentine radiolucencies; (e) internal alveologram; and (f) multiple cystic lesions. (orig.) (orig.) With 12 figs., 13 refs.

  15. Evaluation of dual energy quantitative CT for determining the spatial distributions of red marrow and bone for dosimetry in internal emitter radiation therapy

    International Nuclear Information System (INIS)

    Goodsitt, Mitchell M.; Shenoy, Apeksha; Howard, David; Christodoulou, Emmanuel; Dewaraja, Yuni K.; Shen, Jincheng; Schipper, Matthew J.; Wilderman, Scott; Chun, Se Young

    2014-01-01

    Purpose: To evaluate a three-equation three-unknown dual-energy quantitative CT (DEQCT) technique for determining region specific variations in bone spongiosa composition for improved red marrow dose estimation in radionuclide therapy. Methods: The DEQCT method was applied to 80/140 kVp images of patient-simulating lumbar sectional body phantoms of three sizes (small, medium, and large). External calibration rods of bone, red marrow, and fat-simulating materials were placed beneath the body phantoms. Similar internal calibration inserts were placed at vertebral locations within the body phantoms. Six test inserts of known volume fractions of bone, fat, and red marrow were also scanned. External-to-internal calibration correction factors were derived. The effects of body phantom size, radiation dose, spongiosa region segmentation granularity [single (∼17 × 17 mm) region of interest (ROI), 2 × 2, and 3 × 3 segmentation of that single ROI], and calibration method on the accuracy of the calculated volume fractions of red marrow (cellularity) and trabecular bone were evaluated. Results: For standard low dose DEQCT x-ray technique factors and the internal calibration method, the RMS errors of the estimated volume fractions of red marrow of the test inserts were 1.2–1.3 times greater in the medium body than in the small body phantom and 1.3–1.5 times greater in the large body than in the small body phantom. RMS errors of the calculated volume fractions of red marrow within 2 × 2 segmented subregions of the ROIs were 1.6–1.9 times greater than for no segmentation, and RMS errors for 3 × 3 segmented subregions were 2.3–2.7 times greater than those for no segmentation. Increasing the dose by a factor of 2 reduced the RMS errors of all constituent volume fractions by an average factor of 1.40 ± 0.29 for all segmentation schemes and body phantom sizes; increasing the dose by a factor of 4 reduced those RMS errors by an average factor of 1.71 ± 0.25. Results

  16. SU-E-J-79: Internal Tumor Volume Motion and Volume Size Assessment Using 4D CT Lung Data

    Energy Technology Data Exchange (ETDEWEB)

    Jurkovic, I [University of Texas Health Science Center at San Antonio, San Antonio, TX (United States); Stathakis, S; Li, Y; Patel, A; Vincent, J; Papanikolaou, N; Mavroidis, P [Cancer Therapy and Research Center University of Texas Health Sciences Center at San Antonio, San Antonio, TX (United States)

    2014-06-01

    Purpose: To assess internal tumor volume change through breathing cycle and associated tumor motion using the 4DCT data. Methods: Respiration induced volume change through breathing cycle and associated motion was analyzed for nine patients that were scanned during the different respiratory phases. The examined datasets were the maximum and average intensity projections (MIP and AIP) and the 10 phases of the respiratory cycle. The internal target volume (ITV) was delineated on each of the phases and the planning target volume (PTV) was then created by adding setup margins to the ITV. Tumor motion through the phases was assessed using the acquired 4DCT dataset, which was then used to determine if the margins used for the ITV creation successfully encompassed the tumor in three dimensions. Results: Results showed that GTV motion along the superior inferior axes was the largest in all the cases independent of the tumor location and/or size or the use of abdomen compression. The extent of the tumor motion was found to be connected with the size of the GTV. The smallest GTVs exhibited largest motion vector independent of the tumor location. The motion vector size varied through the phases depending on the tumor size and location and it was smallest for phases 20 and 30. The smaller the volume of the delineated GTV, the greater its volume difference through the different respiratory phases was. The average GTV volume change was largest for the phases 60 and 70. Conclusion: Even if GTV is delineated using both AIP and MIP datasets, its motion extent will exceed the used margins especially for the very small GTV volumes. When the GTV size is less than 10 cc it is recommended to use fusion of the GTVs through all the phases to create the planning ITV.

  17. Visibility and Citation Impact

    Science.gov (United States)

    Ebrahim, Nader Ale; Salehi, Hadi; Embi, Mohamed Amin; Tanha, Farid Habibi; Gholizadeh, Hossein; Motahar, Seyed Mohammad

    2014-01-01

    The number of publications is the first criteria for assessing a researcher output. However, the main measurement for author productivity is the number of citations, and citations are typically related to the paper's visibility. In this paper, the relationship between article visibility and the number of citations is investigated. A case study of…

  18. Viewer Makes Radioactivity "Visible"

    Science.gov (United States)

    Yin, L. I.

    1983-01-01

    Battery operated viewer demonstrates feasibility of generating threedimensional visible light simulations of objects that emit X-ray or gamma rays. Ray paths are traced for two pinhold positions to show location of reconstructed image. Images formed by pinholes are converted to intensified visible-light images. Applications range from radioactivity contamination surveys to monitoring radioisotope absorption in tumors.

  19. In vitro Evaluation of the Marginal Fit and Internal Adaptation of Zirconia and Lithium Disilicate Single Crowns: Micro-CT Comparison Between Different Manufacturing Procedures.

    Science.gov (United States)

    Riccitiello, Francesco; Amato, Massimo; Leone, Renato; Spagnuolo, Gianrico; Sorrentino, Roberto

    2018-01-01

    Prosthetic precision can be affected by several variables, such as restorative materials, manufacturing procedures, framework design, cementation techniques and aging. Marginal adaptation is critical for long-term longevity and clinical success of dental restorations. Marginal misfit may lead to cement exposure to oral fluids, resulting in microleakage and cement dissolution. As a consequence, marginal discrepancies enhance percolation of bacteria, food and oral debris, potentially causing secondary caries, endodontic inflammation and periodontal disease. The aim of the present in vitro study was to evaluate the marginal and internal adaptation of zirconia and lithium disilicate single crowns, produced with different manufacturing procedures. Forty-five intact human maxillary premolars were prepared for single crowns by means of standardized preparations. All-ceramic crowns were fabricated with either CAD-CAM or heat-pressing procedures (CAD-CAM zirconia, CAD-CAM lithium disilicate, heat-pressed lithium disilicate) and cemented onto the teeth with a universal resin cement. Non-destructive micro-CT scanning was used to achieve the marginal and internal gaps in the coronal and sagittal planes; then, precision of fit measurements were calculated in a dedicated software and the results were statistically analyzed. The heat-pressed lithium disilicate crowns were significantly less accurate at the prosthetic margins (p0.05); nevertheless CAD-CAM zirconia copings presented the best marginal fit among the experimental groups. As to the thickness of the cement layer, reduced amounts of luting agent were noticed at the finishing line, whereas a thicker layer was reported at the occlusal level. Within the limitations of the present in vitro investigation, the following conclusions can be drawn: the recorded marginal gaps were within the clinical acceptability irrespective of both the restorative material and the manufacturing procedures; the CAD-CAM processing techniques for

  20. SU-E-J-123: Assessing Segmentation Accuracy of Internal Volumes and Sub-Volumes in 4D PET/CT of Lung Tumors Using a Novel 3D Printed Phantom

    International Nuclear Information System (INIS)

    Soultan, D; Murphy, J; James, C; Hoh, C; Moiseenko, V; Cervino, L; Gill, B

    2015-01-01

    Purpose: To assess the accuracy of internal target volume (ITV) segmentation of lung tumors for treatment planning of simultaneous integrated boost (SIB) radiotherapy as seen in 4D PET/CT images, using a novel 3D-printed phantom. Methods: The insert mimics high PET tracer uptake in the core and 50% uptake in the periphery, by using a porous design at the periphery. A lung phantom with the insert was placed on a programmable moving platform. Seven breathing waveforms of ideal and patient-specific respiratory motion patterns were fed to the platform, and 4D PET/CT scans were acquired of each of them. CT images were binned into 10 phases, and PET images were binned into 5 phases following the clinical protocol. Two scenarios were investigated for segmentation: a gate 30–70 window, and no gating. The radiation oncologist contoured the outer ITV of the porous insert with on CT images, while the internal void volume with 100% uptake was contoured on PET images for being indistinguishable from the outer volume in CT images. Segmented ITVs were compared to the expected volumes based on known target size and motion. Results: 3 ideal breathing patterns, 2 regular-breathing patient waveforms, and 2 irregular-breathing patient waveforms were used for this study. 18F-FDG was used as the PET tracer. The segmented ITVs from CT closely matched the expected motion for both no gating and gate 30–70 window, with disagreement of contoured ITV with respect to the expected volume not exceeding 13%. PET contours were seen to overestimate volumes in all the cases, up to more than 40%. Conclusion: 4DPET images of a novel 3D printed phantom designed to mimic different uptake values were obtained. 4DPET contours overestimated ITV volumes in all cases, while 4DCT contours matched expected ITV volume values. Investigation of the cause and effects of the discrepancies is undergoing

  1. Analyzing Visibility Configurations.

    Science.gov (United States)

    Dachsbacher, C

    2011-04-01

    Many algorithms, such as level of detail rendering and occlusion culling methods, make decisions based on the degree of visibility of an object, but do not analyze the distribution, or structure, of the visible and occluded regions across surfaces. We present an efficient method to classify different visibility configurations and show how this can be used on top of existing methods based on visibility determination. We adapt co-occurrence matrices for visibility analysis and generalize them to operate on clusters of triangular surfaces instead of pixels. We employ machine learning techniques to reliably classify the thus extracted feature vectors. Our method allows perceptually motivated level of detail methods for real-time rendering applications by detecting configurations with expected visual masking. We exemplify the versatility of our method with an analysis of area light visibility configurations in ray tracing and an area-to-area visibility analysis suitable for hierarchical radiosity refinement. Initial results demonstrate the robustness, simplicity, and performance of our method in synthetic scenes, as well as real applications.

  2. Efficient visibility-driven medical image visualisation via adaptive binned visibility histogram.

    Science.gov (United States)

    Jung, Younhyun; Kim, Jinman; Kumar, Ashnil; Feng, David Dagan; Fulham, Michael

    2016-07-01

    'Visibility' is a fundamental optical property that represents the observable, by users, proportion of the voxels in a volume during interactive volume rendering. The manipulation of this 'visibility' improves the volume rendering processes; for instance by ensuring the visibility of regions of interest (ROIs) or by guiding the identification of an optimal rendering view-point. The construction of visibility histograms (VHs), which represent the distribution of all the visibility of all voxels in the rendered volume, enables users to explore the volume with real-time feedback about occlusion patterns among spatially related structures during volume rendering manipulations. Volume rendered medical images have been a primary beneficiary of VH given the need to ensure that specific ROIs are visible relative to the surrounding structures, e.g. the visualisation of tumours that may otherwise be occluded by neighbouring structures. VH construction and its subsequent manipulations, however, are computationally expensive due to the histogram binning of the visibilities. This limits the real-time application of VH to medical images that have large intensity ranges and volume dimensions and require a large number of histogram bins. In this study, we introduce an efficient adaptive binned visibility histogram (AB-VH) in which a smaller number of histogram bins are used to represent the visibility distribution of the full VH. We adaptively bin medical images by using a cluster analysis algorithm that groups the voxels according to their intensity similarities into a smaller subset of bins while preserving the distribution of the intensity range of the original images. We increase efficiency by exploiting the parallel computation and multiple render targets (MRT) extension of the modern graphical processing units (GPUs) and this enables efficient computation of the histogram. We show the application of our method to single-modality computed tomography (CT), magnetic resonance

  3. Visible spectroscopy on ASDEX

    International Nuclear Information System (INIS)

    Hofmann, J.V.

    1991-12-01

    In this report visible spectroscopy and impurity investigations on ASDEX are reviewed and several sets of visible spectra are presented. As a basis for identification of metallic impurity lines during plasma discharges spectra from a stainless steel - Cu arc have been recorded. In a next step a spectrum overview of ASDEX discharges is shown which reveals the dominating role of lines from light impurities like carbon and oxygen throughout the UV and visible range (2000 A ≤ λ ≤ 8000 A). Metallic impurity lines of neutrals or single ionized atoms are observed near localized surfaces. The dramatic effect of impurity reduction by boronization of the vessel walls is demonstrated in a few examples. In extension to some ivesti-gations already published, further diagnostic applications of visible spectroscopy are presented. Finally, the hardware and software system used on ASDEX are described in detail. (orig.)

  4. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... images can be viewed on a computer monitor, printed on film or transferred to a CD or DVD. CT images of internal organs, bones, soft tissue and blood vessels provide greater detail ...

  5. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... internal organs, bones, soft tissues and blood vessels. It may be used to help diagnose abdominal pain ... evaluate blood vessels throughout the body. With CT, it is possible to obtain very detailed pictures of ...

  6. Predicting visibility of aircraft.

    Directory of Open Access Journals (Sweden)

    Andrew Watson

    Full Text Available Visual detection of aircraft by human observers is an important element of aviation safety. To assess and ensure safety, it would be useful to be able to be able to predict the visibility, to a human observer, of an aircraft of specified size, shape, distance, and coloration. Examples include assuring safe separation among aircraft and between aircraft and unmanned vehicles, design of airport control towers, and efforts to enhance or suppress the visibility of military and rescue vehicles. We have recently developed a simple metric of pattern visibility, the Spatial Standard Observer (SSO. In this report we examine whether the SSO can predict visibility of simulated aircraft images. We constructed a set of aircraft images from three-dimensional computer graphic models, and measured the luminance contrast threshold for each image from three human observers. The data were well predicted by the SSO. Finally, we show how to use the SSO to predict visibility range for aircraft of arbitrary size, shape, distance, and coloration.

  7. Measuring visibility using smartphones

    Science.gov (United States)

    Friesen, Jan; Bialon, Raphael; Claßen, Christoph; Graffi, Kalman

    2017-04-01

    Spatial information on fog density is an important parameter for ecohydrological studies in cloud forests. The Dhofar cloud forest in Southern Oman exhibits a close interaction between the fog, trees, and rainfall. During the three month monsoon season the trees capture substantial amounts of horizontal precipitation from fog which increases net precipitation below the tree canopy. As fog density measurements are scarce, a smartphone app was designed to measure visibility. Different smartphone units use a variety of different parts. It is therefore important to assess the developed visibility measurement across a suite of different smartphones. In this study we tested five smartphones/ tablets (Google/ LG Nexus 5X, Huawei P8 lite, Huawei Y3, HTC Nexus 9, and Samsung Galaxy S4 mini) against digital camera (Sony DLSR-A900) and visual visibility observations. Visibility was assessed from photos using image entropy, from the number of visible targets, and from WiFi signal strength using RSSI. Results show clear relationships between object distance and fog density, yet a considerable spread across the different smartphone/ tablet units is evident.

  8. CT pelvimetry

    International Nuclear Information System (INIS)

    Vicens, J.L.; Charles, G.; Le Berre, J.; Flageat, J.

    1989-01-01

    Pelvimetry aims at providing the obstetrician with information on the size and morphology of the female pelvis, thus enabling him to assess the obstetrical prognosis as accurately as possible. Computed tomography (CT) has several advantages, in particular the lower mother and fetus radiation dose. After a brief description of obstetrical anatomy, the usual CT exploration method is presented and its results are considered in terms of measurements, indices and morphological findings. If performed with a very strict exploration procedure, CT pelvimetry is a very reliable, fact and comfortable method of examination. All these advantages, combined with the minimized patient dose, should lead to an increasingly widespread use of this technique [fr

  9. Making Invisible Forces Visible

    DEFF Research Database (Denmark)

    Ratner, Helene Gad

    2013-01-01

    This paper investigates managerial tactics of visualisation when a need to know and manage employees' values and attitudes is expressed. Using the Danish public school as a case study, we explore how school managers use teachers' emotions to render visible presumably invisible information about...... their 'true' attitudes and values. The paper draws on theories of affect as well as actor-network theory to analyse three incidents where managers turn their interpretations of teachers' emotions into such information. These incidents suggest that the efforts to render employees' attitudes and values visible...

  10. CT Scan

    Science.gov (United States)

    ... disease, lung nodules and liver masses Monitor the effectiveness of certain treatments, such as cancer treatment Detect ... scan done in a hospital or an outpatient facility. CT scans are painless and, with newer machines, ...

  11. Thoracic CT

    Science.gov (United States)

    ... through a vein (IV) in your hand or forearm. It may be given through the rectum using ... CT scan Vertebra, thoracic (mid back) Normal lung anatomy Thoracic organs References Gotway MB, Panse PM, Gruden ...

  12. CT Enterography

    Science.gov (United States)

    ... a CT scan can be reformatted in multiple planes, and can even generate three-dimensional images. These ... other medical conditions, and if you have a history of heart disease, asthma, diabetes, kidney disease or ...

  13. Making Invisible Histories Visible

    Science.gov (United States)

    Hanssen, Ana Maria

    2012-01-01

    This article features Omaha Public Schools' "Making Invisible Histories Visible" program, or MIHV. Omaha's schools have a low failure rate among 8th graders but a high one among high school freshmen. MIHV was created to help at-risk students "adjust to the increased demands of high school." By working alongside teachers and…

  14. Visible Solid State Lasers

    NARCIS (Netherlands)

    Hikmet, R.A.M.

    2007-01-01

    Diode lasers can be found in various applications most notably in optical communication and optical storage. Visible lasers were until recently were all based on IR diode lasers. Using GaN, directly blue and violet emitting lasers have also been introduced to the market mainly in the area of optical

  15. Boosting the Visible-Light Photoactivity of BiOCl/BiVO4/N-GQD Ternary Heterojunctions Based on Internal Z-Scheme Charge Transfer of N-GQDs: Simultaneous Band Gap Narrowing and Carrier Lifetime Prolonging.

    Science.gov (United States)

    Zhu, Mingyue; Liu, Qian; Chen, Wei; Yin, Yuanyuan; Ge, Lan; Li, Henan; Wang, Kun

    2017-11-08

    The efficient separation of photogenerated electron-hole pairs in photoactive materials is highly desired, allowing their transfer to specific sites for undergoing redox reaction in various applications. The construction of ternary heterojunctions is a practical strategy to enhance the migration of photogenerated electron that realizes the synergistic effect of multicomponents rather than the simple overlay of single component. Here, we demonstrate an available way to fabricate new BiOCl/BiVO 4 /nitrogen-doped graphene quantum dot (N-GQD) ternary heterojunctions that exhibit higher efficiency in charge separation than any binary heterojunction or pure material under visible-light irradiation. UV-vis diffuse reflectance spectroscopy demonstrated that the proposed BiOCl/BiVO 4 /N-GQD ternary heterojunctions possess the narrower band gap energy. More importantly, the ternary heterojunctions reveal the prolonged lifetime of photogenerated charges and enhanced the separation efficiency of photogenerated electron-hole pairs, which may be ascribed to sensitization based on an internal Z-scheme charge transfer at the interface of N-GQDs with oxygen functional groups. Furthermore, we examine the photoactive performance of proposed ternary heterojunctions in aqueous solution by using the photodegradation of bisphenol A as a model system and BiOCl/BiVO 4 /N-GQD ternary heterojunctions also display a dramatically enhanced photodegradation rate. The proposed charge separation and transfer process of BiOCl/BiVO 4 /N-GQD ternary heterojunctions for the enhanced photoactivity were deduced by electrochemical measurements, photoluminescence, and electron spin resonance. The results demonstrate that a Z-scheme charge process was formed between BiOCl/BiVO 4 binary heterojunctions and N-GQDs, leading to an efficient charge carrier separation and strong photocatalytic ability. Notably, this work may assist in a better understanding of the role of N-GQDs in kinds of heterojunctions

  16. Built-in hyperspectral camera for smartphone in visible, near-infrared and middle-infrared lights region (second report): sensitivity improvement of Fourier-spectroscopic imaging to detect diffuse reflection lights from internal human tissues for healthcare sensors

    Science.gov (United States)

    Kawashima, Natsumi; Hosono, Satsuki; Ishimaru, Ichiro

    2016-05-01

    We proposed the snapshot-type Fourier spectroscopic imaging for smartphone that was mentioned in 1st. report in this conference. For spectroscopic components analysis, such as non-invasive blood glucose sensors, the diffuse reflection lights from internal human skins are very weak for conventional hyperspectral cameras, such as AOTF (Acousto-Optic Tunable Filter) type. Furthermore, it is well known that the spectral absorption of mid-infrared lights or Raman spectroscopy especially in long wavelength region is effective to distinguish specific biomedical components quantitatively, such as glucose concentration. But the main issue was that photon energies of middle infrared lights and light intensities of Raman scattering are extremely weak. For improving sensitivity of our spectroscopic imager, the wide-field-stop & beam-expansion method was proposed. Our line spectroscopic imager introduced a single slit for field stop on the conjugate objective plane. Obviously to increase detected light intensities, the wider slit width of the field stop makes light intensities higher, regardless of deterioration of spatial resolutions. Because our method is based on wavefront-division interferometry, it becomes problems that the wider width of single slit makes the diffraction angle narrower. This means that the narrower diameter of collimated objective beams deteriorates visibilities of interferograms. By installing the relative inclined phaseshifter onto optical Fourier transform plane of infinity corrected optical systems, the collimated half flux of objective beams derived from single-bright points on objective surface penetrate through the wedge prism and the cuboid glass respectively. These two beams interfere each other and form the infererogram as spatial fringe patterns. Thus, we installed concave-cylindrical lens between the wider slit and objective lens as a beam expander. We successfully obtained the spectroscopic characters of hemoglobin from reflected lights from

  17. CT manifestations of peritoneal carcinomatosis.

    Science.gov (United States)

    Walkey, M M; Friedman, A C; Sohotra, P; Radecki, P D

    1988-05-01

    Seventy-three abdominopelvic contrast-enhanced CT scans obtained in 60 patients with peritoneal tumor spread were reviewed retrospectively to determine the CT signs of peritoneal malignancy. Ascites was present in 54 studies (74%) and was the most common CT finding. Loculation of the fluid occurred in 25 (46%) of these. In nine (17%) of the 54, a new finding, absence of cul-de-sac fluid in the presence of generalized ascites, was noted. Parietal peritoneal thickening with contrast enhancement of the peritoneum, making the peritoneum visible as a thin line along the abdominal wall, was present in 45 (62%) of studies. This is believed to represent confluent peritoneal metastases. Small-bowel involvement was present in half of the cases (wall thickening and irregularity with or without obstruction). Tumor involvement of the omentum was visible as soft-tissue permeation of fat, enhancing nodules, and/or an omental cake. Of the 26 patients without a previously known malignancy, identification of the primary tumor in addition to peritoneal carcinomatosis was possible in 13 (50%). Appreciation of the spectrum of CT findings in peritoneal carcinomatosis is essential for accurate evaluation of scans in patients with abdominopelvic malignancies.

  18. Image-Guided Radiation Therapy for Muscle-Invasive Carcinoma of the Urinary Bladder with Cone Beam CT Scan: Use of Individualized Internal Target Volumes for a Single Patient

    Directory of Open Access Journals (Sweden)

    Gagan Saini

    2012-09-01

    Full Text Available Introduction: While planning radiation therapy (RT for a carcinoma of the urinary bladder (CaUB, the intra-fractional variation of the urinary bladder (UB volume due to filling-up needs to be accounted for. This internal target volume (ITV is obtained by adding internal margins (IM to the contoured bladder. This study was planned to propose a method of acquiring individualized ITVs for each patient and to verify their reproducibility. Methods: One patient with CaUB underwent simulation with the proposed ‘bladder protocol’. After immobilization, a planning CT scan on empty bladder was done. He was then given 300 ml of water to drink and the time (T was noted. Planning CT scans were performed after 20 min (T+20, 30 min (T+30 and 40 min (T+40. The CT scan at T+20 was co-registered with the T+30 and T+40 scans. The bladder volumes at 20, 30 and 40 min were then contoured as CTV20, CTV30 and CTV40 to obtain an individualized ITV for our patient. For daily treatment, he was instructed to drink water as above, and the time was noted; treatment was started after 20 min. Daily pre- and post-treatment cone beam CT (CBCT scans were done. The bladder visualized on the pre-treatment CBCT scan was compared with CTV20 and on the post-treatment CBCT scan with CTV30. Results: In total, there were 65 CBCT scans (36 pre- and 29 post-treatment. Individualized ITVs were found to be reproducible in 93.85% of all instances and fell outside in 4 instances. Conclusions: The proposed bladder protocol can yield a reproducible estimation of the ITV during treatment; this can obviate the need for taking standard IMs.

  19. Normal CT anatomy of the spine

    International Nuclear Information System (INIS)

    Quiroga, O.; Matozzi, F.; Beranger, M.; Nazarian, S.; Salamon, G.; Gambarelli, J.

    1982-01-01

    To analyse the anatomo-radiological correlation of the spine and spinal cord, 22 formalized, frozen anatomical specimens corresponding to different regions of the spinal column (8 cervical, 5 dorsal, and 9 lumbar) were studied by CT scans on axial, sagittal and coronal planes and by contact radiography after they were cut into anatomical slices in order to clarify the normal CT anatomy of the spinal column. The results obtained from CT patient scans, performed exclusively on the axial plane, were compared with those obtained from the anatomical specimens (both CT and contrast radiography). High resolution CT programs were used, enabling us to obtain better individualization of the normal structures contained in the spinal column. Direct sagittal and coronal sections were performed on the specimens in order to get further anatomo-radiological information. Enhanced CT studies of the specimens were also available because of the air already present in the subarachnoid spaces. Excellent visualization was obtained of bone structures, soft tissue and the spinal cord. High CT resolution of the spine appeares to be an excellent neuroradiological procedure to study the spine and spinal cord. A metrizamide CT scan is, however, necessary when a normal unenhanced CT scan is insufficient for diagnosis and when the spinal cord is not clearly visible, as often happens at the cervical level. Clinical findings are certainly very useful to ascertain the exact CT level and to limit the radiation exposure. (orig.)

  20. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... create detailed images of your child’s internal organs, bones, soft tissues and blood vessels. It may be used to ... CD or DVD. CT images of internal organs, bones, soft tissue and blood vessels provide greater detail than traditional ...

  1. Social media visibility

    DEFF Research Database (Denmark)

    Uldam, Julie

    2018-01-01

    of activists remains under-researched. This article examines BP’s surveillance of activists who criticise the company’s corporate social responsibility (CSR) programme as ‘greenwashing’. In this way, it goes beyond corporations’ uses of big data and instead explores how they monitor and discuss strategies......As activists move from alternative media platforms to commercial social media platforms, they face increasing challenges in protecting their online security and privacy. While government surveillance of activists is well-documented in scholarly research and the media, corporate surveillance...... for responding to the activities of individual activists in social media. It shows that while social media afford an unprecedented level of visibility for activists, it comes with the risk of being monitored by corporations. Theoretically, it draws on conceptions of visibility in social sciences and media...

  2. Making Heat Visible

    Science.gov (United States)

    Goodhew, Julie; Pahl, Sabine; Auburn, Tim; Goodhew, Steve

    2015-01-01

    Householders play a role in energy conservation through the decisions they make about purchases and installations such as insulation, and through their habitual behavior. The present U.K. study investigated the effect of thermal imaging technology on energy conservation, by measuring the behavioral effect after householders viewed images of heat escaping from or cold air entering their homes. In Study 1 (n = 43), householders who received a thermal image reduced their energy use at a 1-year follow-up, whereas householders who received a carbon footprint audit and a non-intervention control demonstrated no change. In Study 2 (n = 87), householders were nearly 5 times more likely to install draught proofing measures after seeing a thermal image. The effect was especially pronounced for actions that addressed an issue visible in the images. Findings indicate that using thermal imaging to make heat loss visible can promote energy conservation. PMID:26635418

  3. Paradoxes of Visibility

    Directory of Open Access Journals (Sweden)

    Tarnay László

    2017-12-01

    Full Text Available The paper investigates two possible critical arguments following the pictorial turn. The first is formulated within ocularcentrism, the dominance of sight, and starts with the right to visibility as a general principle that governs today’s digital culture but gets twisted in special cases like the Auschwitz photos of the Shoa, the Abu Ghraib prison videos, or recently the website called Yolocaust. The second is conceived outside the visual culture and is meant to vindicate the other senses vis-à-vis the eyes. However, the argument is truncated here only to highlight the boomerang effect of the other senses: haptic vision. It is the case of visual perception when (a there is a lack of things to see and (b indeterminate synaesthesia: when vision intensifies the other senses in the embodied viewer. The two arguments converge upon a dialectic of the visible and the imaginable, which is formulated here as two paradoxes that the discussed examples transcend. By enforcing visibility at all costs where there is hardly anything recognizable to see, they lead to two diverging results. On the one hand, the meaning of “image” is extended toward the unimaginable, the traumatic experience, on the other hand, it is extended toward the invisible, the encounter with the radical Other.

  4. The benefits of visibility

    International Nuclear Information System (INIS)

    Krupnick, A.; DeWitt, D.

    1994-01-01

    The benefits of visibility improvement (or the damages with additional degradation) refer to increases (or decreases) in utility obtained in three different dimensions. The first of these is associated with the nature of the visibility change. Visual range may be improved so that features of an area become more distinct or the sky becomes clearer. Alternatively, normal features of an area may be marred, say by the site of a power plant or its plume (called plume blight). The second dimension is the location of the change: in an urban area, in a rural setting, or in a recreational area or area of particular beauty, such as the Grand Canyon. The third dimension is the type of value: use or non-use. Thus, a person who visits the Grand Canyon (or may visit it in the future) may hold use values for improving his view of the Canyon or its surroundings and may also old non-use values for improved visibility (whether for altruistic or other reasons) irrespective of present or planned visits. In all, therefore, there are 12 possible combinations of the elements in these three dimension, each of which is logically distinct from the others and which demands attention in the literature to derive willingness to pay (WTP)

  5. The benefits of visibility

    Energy Technology Data Exchange (ETDEWEB)

    Krupnick, A; DeWitt, D

    1994-07-01

    The benefits of visibility improvement (or the damages with additional degradation) refer to increases (or decreases) in utility obtained in three different dimensions. The first of these is associated with the nature of the visibility change. Visual range may be improved so that features of an area become more distinct or the sky becomes clearer. Alternatively, normal features of an area may be marred, say by the site of a power plant or its plume (called plume blight). The second dimension is the location of the change: in an urban area, in a rural setting, or in a recreational area or area of particular beauty, such as the Grand Canyon. The third dimension is the type of value: use or non-use. Thus, a person who visits the Grand Canyon (or may visit it in the future) may hold use values for improving his view of the Canyon or its surroundings and may also old non-use values for improved visibility (whether for altruistic or other reasons) irrespective of present or planned visits. In all, therefore, there are 12 possible combinations of the elements in these three dimension, each of which is logically distinct from the others and which demands attention in the literature to derive willingness to pay (WTP)

  6. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses Computed tomography (CT) of the sinuses ... CT of the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed tomography, more commonly known ...

  7. On court interpreters' visibility

    DEFF Research Database (Denmark)

    Dubslaff, Friedel; Martinsen, Bodil

    of the service they receive. Ultimately, the findings will be used for training purposes. Future - and, for that matter, already practising - interpreters as well as the professional users of interpreters ought to take the reality of the interpreters' work in practice into account when assessing the quality...... on the interpreter's interpersonal role and, in particular, on signs of the interpreter's visibility, i.e. active co-participation. At first sight, the interpreting assignment in question seems to be a short and simple routine task which would not require the interpreter to deviate from the traditional picture...

  8. Making Invisible Forces Visible

    DEFF Research Database (Denmark)

    Ratner, Helene Gad

    2013-01-01

    their 'true' attitudes and values. The paper draws on theories of affect as well as actor-network theory to analyse three incidents where managers turn their interpretations of teachers' emotions into such information. These incidents suggest that the efforts to render employees' attitudes and values visible...... install a normative emotional scale where an ideal employee displays emotional investment and self-control. This has implications, not only for employees who are expected to exhibit the 'right' emotions, but also for management, which comes to depend on transient emotions and co-presence in situations...

  9. CT cystography

    International Nuclear Information System (INIS)

    Tsili, A.

    2012-01-01

    Full text: Cancer of the urinary bladder is one of the commonest urothelial neoplasms. Conventional cystoscopy remains the mainstay in the diagnosis of urinary bladder carcinomas. But it is an invasive and uncomfortable procedure, associated with complications. Computed tomographic (CT) virtual cystoscopy has been proposed as an alternative imaging modality with potential advantages in the detection of urinary bladder neoplasms and good patient acceptance. It is a minimally invasive technique, allowing imaging of the urinary bladder in multiple planes and a 360 0 view. CT cystoscopy provides information about the location, size and morphologic features of urinary bladder lesions, indicating appropriate areas for biopsy. It can be performed in cases in which conventional cystoscopy is not feasible, such as in the presence of urethral strictures, marked prostatic hypertrophy or active bleeding, and in cases in which cystoscopic findings are inconclusive. The technique can be used to evaluate areas of the urinary bladder difficult to evaluate with cystoscopy, such as the anterior bladder neck and narrowmouthed diverticula. Finally, virtual cystoscopy provides both intraluminal and extraluminal pathologic changes, so intravesical disease and exrtavesical extension can be evaluated in the same study. One of the limitations of this technique is the difficulty to demonstrate small-sized lesions. The introduction of multi-detector row CT (MDCT) scanners was a major technological advancement because among other things it substantially improves z-axis resolution by reducing section collimation and allowing the detection of very small lesions. The near isotropic or isotropic pixels achieved with a multidetector CT scanner, enable the creation of multiplanar reformatted images with a resolution very close to that of the axial images and three-dimensional (3D) renderings of outstanding quality. Transverse, multiplanar reformations and virtual endoscopic images are complementary

  10. Visibility of sutures of the orbit and periorbital region using multidetector computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Gufler, Hubert; Preis, Markus; Koesling, Sabrina [Dept. of Diagnostic Radiology, Martin-Luther-University Halle-Wittenberg, Halle (Germany)

    2014-12-15

    Knowledge of cranial suture morphology is crucial in emergency medicine, forensic medicine, and maxillofacial reconstructive surgery. This study assessed the visibility of sutures of the orbit and periorbital region on multidetector computed tomography. Multidetector computed tomography scans of 200 patients (127 males, 73 females; mean age 51.3 years; range, 6-92 years) were evaluated retrospectively. The slice thicknesses varied from 0.5 to 1 mm, and the tube current from 25 to 370 mAs, depending on the CT indication. The visibility of sutures was estimated according to a 4-point scale from 'not visible to well visible' The chi-squared test was used to test the association of the visibility of sutures with the slice thickness, tube current, and age of patients. Statistical significance was assumed at p < 0.05. Overall, best visibility was found for the sutura frontozygomatica (98%), sutura frontonasalis (88.5%), and sutura sphenozygomatica (71.5%), followed by the sutura zygomaticomaxillaris (65.8%), sutura temporozygomatica (41.8%), sutura frontomaxillaris (44.5%), and sutura sphenofrontalis (31%). Poor visibility was found for the sutura frontolacrimalis (16.8%) and sutura frontoethmoidalis (1.3%). The sutura ethmoidomaxillaris, sutura lacrimomaxillaris, and sutura ethmoidolacrimalis were not visible. Although the sutures of the superior, lateral, and inferior orbit are well visible, those of the medial orbit are poorly visible on CT scans.

  11. International

    International Nuclear Information System (INIS)

    Anon.

    1997-01-01

    This rubric reports on 10 short notes about international economical facts about nuclear power: Electricite de France (EdF) and its assistance and management contracts with Eastern Europe countries (Poland, Hungary, Bulgaria); Transnuclear Inc. company (a 100% Cogema daughter company) acquired the US Vectra Technologies company; the construction of the Khumo nuclear power plant in Northern Korea plays in favour of the reconciliation between Northern and Southern Korea; the delivery of two VVER 1000 Russian reactors to China; the enforcement of the cooperation agreement between Euratom and Argentina; Japan requested for the financing of a Russian fast breeder reactor; Russia has planned to sell a floating barge-type nuclear power plant to Indonesia; the control of the Swedish reactor vessels of Sydkraft AB company committed to Tractebel (Belgium); the renewal of the nuclear cooperation agreement between Swiss and USA; the call for bids from the Turkish TEAS electric power company for the building of the Akkuyu nuclear power plant answered by three candidates: Atomic Energy of Canada Limited (AECL), Westinghouse (US) and the French-German NPI company. (J.S.)

  12. Implications of CT noise and artifacts for quantitative 99mTc SPECT/CT imaging

    International Nuclear Information System (INIS)

    Hulme, K. W.; Kappadath, S. C.

    2014-01-01

    Purpose: This paper evaluates the effects of computed tomography (CT) image noise and artifacts on quantitative single-photon emission computed-tomography (SPECT) imaging, with the aim of establishing an appropriate range of CT acquisition parameters for low-dose protocols with respect to accurate SPECT attenuation correction (AC). Methods: SPECT images of two geometric and one anthropomorphic phantom were reconstructed iteratively using CT scans acquired at a range of dose levels (CTDI vol = 0.4 to 46 mGy). Resultant SPECT image quality was evaluated by comparing mean signal, background noise, and artifacts to SPECT images reconstructed using the highest dose CT for AC. Noise injection was performed on linear-attenuation (μ) maps to determine the CT noise threshold for accurate AC. Results: High levels of CT noise (σ ∼ 200–400 HU) resulted in low μ-maps noise (σ ∼ 1%–3%). Noise levels greater than ∼10% in 140 keV μ-maps were required to produce visibly perceptible increases of ∼15% in 99m Tc SPECT images. These noise levels would be achieved at low CT dose levels (CTDI vol = 4 μGy) that are over 2 orders of magnitude lower than the minimum dose for diagnostic CT scanners. CT noise could also lower (bias) the expected μ values. The relative error in reconstructed SPECT signal trended linearly with the relative shift in μ. SPECT signal was, on average, underestimated in regions corresponding with beam-hardening artifacts in CT images. Any process that has the potential to change the CT number of a region by ∼100 HU (e.g., misregistration between CT images and SPECT images due to motion, the presence of contrast in CT images) could introduce errors in μ 140 keV on the order of 10%, that in turn, could introduce errors on the order of ∼10% into the reconstructed 99m Tc SPECT image. Conclusions: The impact of CT noise on SPECT noise was demonstrated to be negligible for clinically achievable CT parameters. Because CT dose levels that affect

  13. Cardiac CT

    International Nuclear Information System (INIS)

    Dewey, Marc

    2011-01-01

    Computed tomography of the heart has become a highly accurate diagnostic modality that is attracting increasing attention. This extensively illustrated book aims to assist the reader in integrating cardiac CT into daily clinical practice, while also reviewing its current technical status and applications. Clear guidance is provided on the performance and interpretation of imaging using the latest technology, which offers greater coverage, better spatial resolution, and faster imaging. The specific features of scanners from all four main vendors, including those that have only recently become available, are presented. Among the wide range of applications and issues to be discussed are coronary artery bypass grafts, stents, plaques, and anomalies, cardiac valves, congenital and acquired heart disease, and radiation exposure. Upcoming clinical uses of cardiac CT, such as plaque imaging and functional assessment, are also explored. (orig.)

  14. Cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Dewey, Marc [Charite - Universitaetsmedizin Berlin (Germany). Inst. fuer Radiologie

    2011-07-01

    Computed tomography of the heart has become a highly accurate diagnostic modality that is attracting increasing attention. This extensively illustrated book aims to assist the reader in integrating cardiac CT into daily clinical practice, while also reviewing its current technical status and applications. Clear guidance is provided on the performance and interpretation of imaging using the latest technology, which offers greater coverage, better spatial resolution, and faster imaging. The specific features of scanners from all four main vendors, including those that have only recently become available, are presented. Among the wide range of applications and issues to be discussed are coronary artery bypass grafts, stents, plaques, and anomalies, cardiac valves, congenital and acquired heart disease, and radiation exposure. Upcoming clinical uses of cardiac CT, such as plaque imaging and functional assessment, are also explored. (orig.)

  15. CT-Urography; Urografia CT

    Energy Technology Data Exchange (ETDEWEB)

    Dalla Palma, Ludovico; Grotto, Maurizio [Trieste Univ., Trieste (Italy). Dipartimento di scienze cliniche, morfologiche e tecnologiche, UCO di radiologia; Morra, Aldo [CRO, Aviano (Italy). Reparto di radiologia

    2005-09-15

    In this paper we present an overview of CT-Urography. With the advent of multislice CT scanners and the evolution of image processing methods this technique now affords optimal urographic images comparable to those obtained with conventional techniques. We describe the acquisition techniques and protocols used by the various authors. Effective radiation dose has conditioned the use of CT-Urography so that the tendency today is to reduce the number of scans by performing, after the non enhanced scan, a single contrast-enhanced scan comprising both the nephrographic and urographic phase. With the use of multislice CT the quality of the urogram improves with the number of slices. We illustrate a variety of processing techniques, multiplanar reconstruction (MPR), maximum (MIP) and average intensity projection (AIP) and volume rendering (VR) and present a series of upper urinary tract tumours testifying to the superiority of the AIP technique over MIP. We then review the results of comparative studies of CT-Urography with conventional urography in upper urinary tract diagnostics. Finally, we describe the advantages and limitations of CT-Urography. [Italian] Gli Autori presentano una panoramica sulla Urografia TC (Uro TC). L'avvento della TC multistrato e l'evoluzione delle tecniche di elaborazione consentono di ottenere dei quadri urografici ottimali comparativi con quelli convenzionali. Vengono ricordate le varie tecniche di acquisizione e i protocolli usati dai vari Autori. La dose effettiva di radiazioni ha rappresentato uno dei fattori condizionanti per cui oggi prevale l'orientamento di ridurre il numero di scansioni, considerando dopo la scansione senza mezzo di contrasto un'unica scansione contrasto grafica comprendente sia la fase nefrografica che quella urografica. Con l'uso della TC multistrato la qualita dell'urogramma migliora con l'aumento del numero degli strati. Vengono descritte le varie tecniche di elaborazione, la

  16. Visible but Unseen?

    DEFF Research Database (Denmark)

    Torkilsheyggi, Arnvør Martinsdóttir á; Hertzum, Morten

    2015-01-01

    Studies have shown that whiteboards support much cooper-ative work by for example strengthening awareness, im-proving communication, and reducing mental workload. In line with these predominantly positive findings, an emer-gency department (ED) turned to its whiteboard to improve the coordination...... of its work with blood tests. We investi-gate this use of the whiteboard through observations and informal interviews in the ED and analyze the ability of the whiteboard to support coordination and awareness in the work with blood tests. Our findings show limitations in the ability of the whiteboard...... to support awareness in a setting where the users are (locally) mobile, specifically in regard to information that requires continuous monitoring. We do however also find that the whiteboard safeguarded the work with blood tests against some risks by making blood-test information socially visible....

  17. An original micro-CT study and meta-analysis of the internal and external anatomy of maxillary molars - implications for endodontic treatment.

    Science.gov (United States)

    Tomaszewska, Iwona M; Jarzębska, Anna; Skinningsrud, Bendik; Pękala, Przemysław A; Wroński, Sebastian; Iwanaga, Joe

    2018-05-07

    The aim of this work was to conduct a radiological micro-CT study and meta-analysis to determine the morphological features of the root canal anatomy of the maxillary molars. The radiological study included micro-CT scans of 110 maxillary first molars and 98 maxillary second molars. To identify articles eligible for inclusion in our meta-analysis, PubMed, Embase, and Web of Science were search comprehensively. The following data were extracted: study type (cadaveric, intraoperative or imaging), Vertucci types of canal configuration, presence/number of canals, roots, apical foramina, apical deltas, and inter-canal communications. The mesiobuccal root was the most variable with respect to canal configuration, type I being the most common configuration followed by type II and type IV. Type I was the most common canal configuration in the distobuccal and palatal root. Regarding the number of canals in the maxillary first and second molars, one canal was most prevalent in all roots of the three molars, except for the mesiobuccal root of maxillary first molar, in which two canals were most prevalent. The most prevalent number of roots in all maxillary molars was three. Knowledge of endodontic anatomy determines the parameters of root canal treatment and significantly affects the probability of success. It is therefore especially important to know the morphology of the root canal system in order to perform endodontic treatment correctly. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

  18. CT urography

    Energy Technology Data Exchange (ETDEWEB)

    Korobkin, M. [Dept. of Radiology, Univ. of Michigan, Ann Arbor, MI (United States)

    2005-11-15

    With the advent of multidetector row CT scanners, evaluation of the urothelium of the entire urinary tract with high-resolution thin sections during a single breath-hold has become a reality. Multidetector CT urography (MDCTU) is a single examination that allows evaluation of potential urinary tract calculi, renal parenchymal masses, and both benign and malignant urothelial lesions. Initial results with this new technique are encouraging. Current investigations of MDCTU focus on methods to improve opacification and distension of the upper urinary tract - the collecting systems, pelvis, and ureters. The role of abdominal compression, infusion of saline and/or furosemide, and optimal time delay of excretory phase imaging is being explored. Upper tract urothelial malignancies, including small lesions less the 5 mmin diameter, can be detected with high sensitivity. Methods to reduce radiation exposure are being explored, including split-bolus contrast injection techniques that combine nephrographic and excretory phases into a single phase. It is likely that in the near future, radiological evaluation of significant unexplained hematuria or of known or prior urothelial malignancy will consist of a single examination - MDCTU. (orig.)

  19. Internal and external morphology of mandibular molars: An original micro-CT study and meta-analysis with review of implications for endodontic therapy.

    Science.gov (United States)

    Tomaszewska, Iwona M; Skinningsrud, Bendik; Jarzębska, Anna; Pękala, Jakub R; Tarasiuk, Jacek; Iwanaga, Joe

    2018-03-25

    The aim of this radiological micro-CT study and meta-analysis was to determine the morphological features of the root canal anatomy of the mandibular molars. The radiological study included micro-CT scans of 108 mandibular first, 120 mandibular second, and 146 mandibular third molars. For our meta-analysis, an extensive search was conducted through PubMed, Embase, and Web of Science to identify articles eligible for inclusion. Data extracted included investigative method (cadaveric, intraoperative, or imaging), Vertucci type of canal configuration, presence/number of canals, roots, apical foramina, apical deltas, and intercanal communications. In the mesial roots of mandibular molars, the most frequent Vertucci type of canal configuration was type IV, except for the mandibular third molar where type I was most common. Type I was most common in the distal root. There were usually two canals in the mesial root and one in the distal root. Two was the most common number of roots, and a third root was most prevalent in Asia. One apical foramen was most common in the distal root and two apical foramina in the mesial root. Intercanal communications were most frequent in the mesial root. Knowledge of the complex anatomy of the mandibular molars can make root canal therapy more likely to succeed. We recommend the use of cone-beam computed tomography before and after endodontic treatment to enable the root anatomy to be accurately described and properly diagnosed, and treatment outcome to be assessed. Clin. Anat. 00:000-000, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

  20. Revisiting visibility in the plane

    DEFF Research Database (Denmark)

    Wilkinson, Bryan Thomas

    Abstract We consider two closely related problems: computing the region visible from a point amid simple polygonal obstacles and computing the lower envelope of a set of disjoint segments. Visibility problems such as these were proposed and promptly solved in the late'80s and early'90s before...

  1. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... are the limitations of CT of the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed ... nasal cavity by small openings. top of page What are some common uses of the procedure? CT ...

  2. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... the limitations of CT Scanning of the Head? What is CT Scanning of the Head? Computed tomography, ... than regular radiographs (x-rays). top of page What are some common uses of the procedure? CT ...

  3. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ... preferable over CT scanning. top of page Additional Information and Resources RTAnswers.org: Radiation Therapy for Bladder ...

  4. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ...

  5. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ...

  6. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ...

  7. Evaluation of temporal bone pneumatization on high resolution CT (HRCT) measurements of the temporal bone in normal and otitis media group and their correlation to measurements of internal auditory meatus, vestibular or cochlear aqueduct

    International Nuclear Information System (INIS)

    Nakamura, Miyako

    1988-01-01

    High resolution CT axial scans were made at the three levels of the temoral bone 91 cases. These cases consisted of 109 sides of normal pneumatization (NR group) and 73 of poor pneumatization resulted by chronic otitis (OM group). NR group included sensorineural hearing loss cases and/or sudden deafness on the side. Three levels of continuous slicing were chosen at the internal auditory meatus, the vestibular and the cochlear aqueduct, respectively. In each slice two sagittal and two horizontal measurements were done on the outer contour of the temporal bone. At the proper level, diameter as well as length of the internal acoustic meatus, the vestibular or the cochlear aqueduct were measured. Measurements of the temporal bone showed statistically significant difference between NR and OM groups. Correlation of both diameter and length of the internal auditory meatus to the temporal bone measurements were statistically significant. Neither of measurements on the vestibular or the cochlear aqueduct showed any significant correlation to that of the temporal bone. (author)

  8. A case of falx meningiomas showing an unusual extension on CT

    International Nuclear Information System (INIS)

    Tsuha, Mitsuru; Fudaba, Hiroyoshi; Orita, Tetsuji; Wakuta, Yukio; Aoki, Hideo

    1986-01-01

    It is well known that homogeneous high-density areas with well-defined borders and marked contrast enhancements on CT scans are characteristic features of meningiomas. However, there are a few cases of meningiomas which are more difficult to diagnose because of their unusual CT findings. We have, for example, recently experienced a case of falx meningioma with a small attachment to the flax and a large exophytic component in the brain parenchyma. This 53-year-old female had complained of dull headaches for several years. She had then suffered speech disturbance in June, 1983, followed by a weakness of her right arm. She was referred to our clinic on Oct. 31, 1983. The neurological findings on admission were dyscalculia, mild motor dysphasia, and right hemiparesis to a minor degree. CT revealed a left frontal iso- and high-density mass lesion and also central, partly visible, low-density areas. A postinfusion study showed a moderate contrast enhancement. Also noted were a partial attachment of these tumors to the falx and a more prominent contrast enhancement of these areas than those of other tumor sites. A left internal carotid angiogram revealed a frontal tumor stain, fed by the left ACA and MCAs; early venous drainage was also seen. Moreover, left external carotid angiography showed a small tumor stain adjacent to the falx. Left frontoparietal craniotomy, on Nov. 14, 1983, revealed a soft, well-defined tumor, partly attached to the tumor. Histology indicated a meningioma with partial anisocytosis and mitoses of tumor cells; this was consequently diagnosed as a malignant meningioma. Intracranial meningiomas with a small attachment to the falx and large areas of exophytic components are rare CT findings. In addition to the CT findings mentioned above, the heterogeneity of the absorption coefficients of meningiomas on CT and differential diagnosis were discussed. (author)

  9. Inflammatory pseudotumor of the liver: CT findings

    International Nuclear Information System (INIS)

    Lee, Kang Mo; Yoon, Kwon Ha; Rho, Ji Young; Park, Ki Han; Yun, Ki Jung; Kim, Chang Keun; Won, Jong Jin; Ha, Hyun Kwon; Suh, Jae Hee; Auh, Yong Ho

    1998-01-01

    To evaluate the CT features of inflammatory pseudotumor of the liver with histopathologic correlation. The CT features of 14 cases (ten patients) with pathologically proven inflammatory hepatic pseudotumor were retrospectively analyzed and correlated with resected and biopsy specimens. The size of lesions ranged between 2.0 and 7.0cm (mean, 3.7 cm); On unenhanced CT, the masses were seen as ill-defined hypodense lesions, while on contrast-enhanced CT they were heterogeneous and multiseptated, with enhancement of internal septa and peripheral wall (n=3D10). In four lesions, central low density and peripheral homogeneous enhancement were seen. On histopathological correlation, the central hypoattenuated area corresponded to chronic inflammatory cell infiltrates with foamy histiocytes, plasmacytes, and lymphocytes, while the hyperattenuated peripheral wall and internal septa represented dense fibrosis. In patients in whon CT shows a heterogeneous enhancing mass, inflammatory pseudotumor of the liver should be included in differential diagnosis

  10. CT diagnostic significance of tuboovarian abscess

    International Nuclear Information System (INIS)

    Du Tieqiao; Dong Jie; Xu Quanying; An Haiqin; Sang Chunyu

    2006-01-01

    Objective: To analyze computed tomographic (CT) imaging features of tuboovarian abscess as well as to discuss CT diagnostic significance. Methods: Ten patients with tuboovarian abscess were performed CT enhancing scans. Results: Ten patients manifested thick-walled, cystic-solid complex adnexal mass and indistinct margins on CT imaging. Internal thick septations and layered enhancement of the mass border on CT contrast images were common. Associated findings of CT included thickening of' the uterosacral ligaments in 9 of 10 patients, increased attenuation of the presacral and perirectal fat secondary to edema in 9 patients, serpiginous structure corresponding to a dilated, pus-filled fallopian tube in 6 patients and fluid-filled within uterine cavity in 4 patients. On CT scans, the inflammatory infiltration of adnexal abscesses involved pelvic structure included adhesion with borders of uterus in 9 patients, adhesion with rectal or sigmoid in 4 patients and pelvic wall or bowel loop in 3 patients. Two cases with peritoneal thicken showed ascites on CT images and right adnexal tuboovarian abscess in 2 patients were associated with appendicitis. Conclusion: CT can reveal pelvic adjacent organs involvement or adhesion and inflammatory infihration of pelvic floor soft-tissues or fascial planes except showing cystic solid complex mass of adnexal location so that indicating characteristics and the extent of the suspected pelvic inflammatory diseases. CT can be valuable in difficult cases of gynecologic infective diseases. (authors)

  11. Clinical applications of SPECT-CT

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadzadehfar, Hojjat; Biersack, Hans-Juergen (eds.) [University Hospital Bonn (Germany). Dept. of Nuclear Medicine

    2014-06-01

    Covers the full spectrum of clinical applications of SPECT/CT in diagnosis of benign and malignant diseases. Includes chapters on the use of SPECT/CT for dosimetry and for therapy planning. Completely up to date. Many helpful illustrations. SPECT/CT cameras have considerably improved diagnostic accuracy in recent years. Such cameras allow direct correlation of anatomic and functional information, resulting in better localization and definition of scintigraphic findings. In addition to this anatomic referencing, CT coregistration provides superior quantification of radiotracer uptake based on the attenuation correction capabilities of CT. Useful applications of SPECT/CT have been identified not only in oncology but also in other specialties such as orthopedics and cardiology. This book covers the full spectrum of clinical applications of SPECT/CT in diagnosis and therapy planning of benign and malignant diseases. Opening chapters discuss the technology and physics of SPECT/CT and its use for dosimetry. The role of SPECT/CT in the imaging of a range of pathologic conditions is then addressed in detail. Applications covered include, among others, imaging of the thyroid, bone, and lungs, imaging of neuroendocrine tumors, cardiac scintigraphy, and sentinel node scintigraphy. Individual chapters are also devoted to therapy planning in selective internal radiation therapy of liver tumors and bremsstrahlung SPECT/CT. Readers will find this book to be an essential and up-to-date source of information on this invaluable hybrid imaging technique.

  12. Flat-panel detector volumetric CT for visualization of subarachnoid hemorrhage and ventricles: preliminary results compared to conventional CT

    International Nuclear Information System (INIS)

    Doelken, M.; Struffert, T.; Richter, G.; Engelhorn, T.; Doerfler, A.; Nimsky, C.; Ganslandt, O.; Hammen, T.

    2008-01-01

    The aim of this study was to compare flat-panel volumetric CT (VCT) to conventional CT (cCT) in the visualization of the extent of subarachnoid hemorrhage (SAH) and the width of the ventricles in patients with acute SAH. Included in the study were 22 patients with an acutely ruptured cerebral aneurysm who received VCT during coil embolization. VCT image quality, the extent of SAH (using a modified Fisher score and total slice number with SAH visible) and the width of the ventricles (Evans index) were evaluated by two experienced neuroradiologists (RAD1 and RAD2) and compared to the findings on cCT. Ten patients undergoing VCT for reasons other than SAH served as negative controls. Interobserver agreement in rating image quality was excellent for cCT (Kendall W value 0.94) and good for VCT (0.74). SAH was identified by RAD1 and RAD2 on VCT images in all patients. The modified Fisher scores underestimated the extent of SAH on VCT images in comparison with cCT images. Pearson's correlation coefficient (r) regarding the number of image slices with SAH visible on cCT images compared with the number on VCT images was 0.85 for RAD1 and 0.84 for RAD2. The r value for the degree of interobserver agreement for the number of slices with SAH visible was 0.99 for cCT, and 0.95 for VCT images (n 19), respectively. The width of the ventricles measured in terms of the Evans Index showed excellent concordance between the modalities (r = 0.81 vs. 0.82). Our preliminary results indicate that VCT is helpful in evaluating SAH in the angiography suite. Additionally, reliable evaluation of ventricle width is feasible. However, there are limitations with regard to the visibility of SAH on VCT images in comparison to cCT images. (orig.)

  13. On characterizing terrain visibility graphs

    Directory of Open Access Journals (Sweden)

    William Evans

    2015-06-01

    Full Text Available A terrain is an $x$-monotone polygonal line in the $xy$-plane. Two vertices of a terrain are mutually visible if and only if there is no terrain vertex on or above the open line segment connecting them. A graph whose vertices represent terrain vertices and whose edges represent mutually visible pairs of terrain vertices is called a terrain visibility graph. We would like to find properties that are both necessary and sufficient for a graph to be a terrain visibility graph; that is, we would like to characterize terrain visibility graphs.Abello et al. [Discrete and Computational Geometry, 14(3:331--358, 1995] showed that all terrain visibility graphs are “persistent”. They showed that the visibility information of a terrain point set implies some ordering requirements on the slopes of the lines connecting pairs of points in any realization, and as a step towards showing sufficiency, they proved that for any persistent graph $M$ there is a total order on the slopes of the (pseudo lines in a generalized configuration of points whose visibility graph is $M$.We give a much simpler proof of this result by establishing an orientation to every triple of vertices, reflecting some slope ordering requirements that are consistent with $M$ being the visibility graph, and prove that these requirements form a partial order. We give a faster algorithm to construct a total order on the slopes. Our approach attempts to clarify the implications of the graph theoretic properties on the ordering of the slopes, and may be interpreted as defining properties on an underlying oriented matroid that we show is a restricted type of $3$-signotope.

  14. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) is a fast, painless exam that uses special ... the limitations of Children's CT? What is Children's CT? Computed tomography, more commonly known as a CT or CAT ...

  15. Micro-CT and nano-CT analysis of filling quality of three different endodontic sealers.

    Science.gov (United States)

    Huang, Yan; Celikten, Berkan; de Faria Vasconcelos, Karla; Ferreira Pinheiro Nicolielo, Laura; Lippiatt, Nicholas; Buyuksungur, Arda; Jacobs, Reinhilde; Orhan, Kaan

    2017-12-01

    To investigate voids in different root canal sealers using micro-CT and nano-CT, and to explore the feasibility of using nano-CT for quantitative analysis of sealer filling quality. 30 extracted mandibular central incisors were randomly assigned into three groups according to the applied root canal sealers (Total BC Sealer, Sure Seal Root, AH Plus) by the single cone technique. Subsequently, micro-CT and nano-CT were performed to analyse the incidence rate of voids, void fraction, void volume and their distribution in each sample. Micro-CT evaluation showed no significant difference among sealers for the incidence rate of voids or void fraction in the whole filling materials (p > 0.05), whereas a significant difference was found between AH Plus and the other two sealers using nano-CT (p nano-CT results displayed higher void volume in AH Plus among all the sealers and regions (p nano-CT analysis, when round root canals were treated by the single cone technique. The disparate results suggest that the higher resolution of nano-CT have a greater ability of distinguishing internal porosity, and therefore suggesting the potential use of nano-CT in quantitative analysis of filling quality of sealers.

  16. Incremental Visualizer for Visible Objects

    DEFF Research Database (Denmark)

    Bukauskas, Linas; Bøhlen, Michael Hanspeter

    This paper discusses the integration of database back-end and visualizer front-end into a one tightly coupled system. The main aim which we achieve is to reduce the data pipeline from database to visualization by using incremental data extraction of visible objects in a fly-through scenarios. We...... also argue that passing only relevant data from the database will substantially reduce the overall load of the visualization system. We propose the system Incremental Visualizer for Visible Objects (IVVO) which considers visible objects and enables incremental visualization along the observer movement...... path. IVVO is the novel solution which allows data to be visualized and loaded on the fly from the database and which regards visibilities of objects. We run a set of experiments to convince that IVVO is feasible in terms of I/O operations and CPU load. We consider the example of data which uses...

  17. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head Computed tomography (CT) of the head uses special x-ray ... What is CT Scanning of the Head? Computed tomography, more commonly known as a CT or CAT ...

  18. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Abdomen and Pelvis Computed tomography (CT) of the abdomen and pelvis is a ... is CT Scanning of the Abdomen/Pelvis? Computed tomography, more commonly known as a CT or CAT ...

  19. The appearance of foramen in the internal aspect of the mental region of mandible from japanese cadavers and dry skulls under macroscopic observation and three-dimensional CT images

    International Nuclear Information System (INIS)

    Yoshida, Shunji; Kawai, Taisuke; Okutsu, Koichiro; Yosue, Takashi; Sunohara, Masataka; Sato, Iwao; Takamori, Hitoshi

    2005-01-01

    The lingual canal with foramen displays different appearances on the internal surfaces of mandible as confirmed by macroscopic observation and computerized tomography (CT). The lingual canal was observed in the inside of mental region run to the outside of lingual foramen, which is extend internally from mandibular canal in right and left sides of the mandible in cadavers (13 sides out of 88 sides) and in dry skulls (43 out of 94 sides) examined. The spinal foramen connected with mental canal occurred at the midline of mandible in 6 cases (6 out of 47 cases) in dry skulls. In this small foramen, the inferior alveolar artery give some branches to the inside of mental region at the anterior mandible and which may be run pass through the lingual canal to the lingual foramen, where they emerge to enter the mylohyoid or anterior belly of digastric muscles. The observations of these are important considerations for surgical placement of dental implants in the region in the mandible. (author)

  20. Visible neutrino decay at DUNE

    Energy Technology Data Exchange (ETDEWEB)

    Coloma, Pilar [Fermilab; Peres, Orlando G. [ICTP, Trieste

    2017-05-09

    If the heaviest neutrino mass eigenstate is unstable, its decay modes could include lighter neutrino eigenstates. In this case part of the decay products could be visible, as they would interact at neutrino detectors via mixing. At neutrino oscillation experiments, a characteristic signature of such \\emph{visible neutrino decay} would be an apparent excess of events at low energies. We focus on a simple phenomenological model in which the heaviest neutrino decays as $\

  1. Simultaneous validation of the SunTech CT40 automated blood pressure measurement device by the 1993 British Hypertension Society protocol and the Association for the Advancement of Medical Instrumentation/International Organization for Standardization 81060-2: 2013 standard.

    Science.gov (United States)

    Polo Friz, Hernan; Punzi, Veronica; Petri, Francesco; Orlandi, Riccardo; Maggiolini, Daniele; Polo Friz, Melisa; Primitz, Laura; Vighi, Giuseppe

    2017-10-01

    This study aimed to perform a simultaneous, third-party, independent validation of the oscillometric SunTech CT40 device for blood pressure (BP) measurement, according to the 1993 protocol of the British Hypertension Society and the standard of the Association for the Advancement of Medical Instrumentation (AAMI)/the International Organization for Standardization (ISO) 81060-2:2013. Patient recruitment, study procedures, and data analysis followed the recommendations stated by the protocols. The study was approved by the institutional review board. A total of 94 participants were included, 52 (55.3%) women, mean±SD age: 63.1±18.0 years, mean±SD arm circumference: 35.0±9.0 cm. The average of observers' entry BPs was 146.9±37.2 mmHg for systolic blood pressure (SBP) and 82.2±22.1 mmHg for diastolic blood pressure (DBP). Differences between the standard measurement and the test device within 5, 10, and 15 mmHg, for the better observer, were 79.4, 96.5, and 100.0% for SBP and 82.6, 97.5, and 100.0% for DBP, respectively. The mean±SD differences between the readings obtained using the test device and those obtained by the observers (AAMI/ISO 81060-2:2013 standard criterion 1) were 0.3±5.0 mmHg (SBP) and -0.8±4.3 mmHg (DBP), and the mean±SD differences between average of reference readings and average of test device readings in each patient (criterion 2) were 0.3±3.9 and -0.8±3.5 mmHg for SBP and DBP, respectively. The CT40 BP device achieved A/A grade of the British Hypertension Society protocol and fulfilled the requirements (criteria 1 and 2) of the AAMI/ISO standard. CT40 can be recommended for BP measurement in adults.

  2. Posterior defects of the patella on CT arthrograms

    International Nuclear Information System (INIS)

    Lehner, K.; Reiser, M.; Hawe, W.; Smasal, V.; Technische Univ. Muenchen; Technische Univ. Muenchen

    1986-01-01

    Changes of the posterior bony and cartilaginous surfaces of the patella as seen on CT arthrograms are described in the case of bipartite patellae, fractures and ossification defects. Contrary to present opinion, cartilaginous lesions are frequently seen on CT arthrograms. This is also true for discreet and partial ossification defects which are not visible on conventional X-rays and are described here for the first time. The aetiology, morphogenesis and clinical examples are discussed. (orig.) [de

  3. Digital tomosynthesis for evaluating metastatic lung nodules: nodule visibility, learning curves, and reading times.

    Science.gov (United States)

    Lee, Kyung Hee; Goo, Jin Mo; Lee, Sang Min; Park, Chang Min; Bahn, Young Eun; Kim, Hyungjin; Song, Yong Sub; Hwang, Eui Jin

    2015-01-01

    To evaluate nodule visibility, learning curves, and reading times for digital tomosynthesis (DT). We included 80 patients who underwent computed tomography (CT) and DT before pulmonary metastasectomy. One experienced chest radiologist annotated all visible nodules on thin-section CT scans using computer-aided detection software. Two radiologists used CT as the reference standard and retrospectively graded the visibility of nodules on DT. Nodule detection performance was evaluated in four sessions of 20 cases each by six readers. After each session, readers were unblinded to the DT images by revealing the true-positive markings and were instructed to self-analyze their own misreads. Receiver-operating-characteristic curves were determined. Among 414 nodules on CT, 53.3% (221/414) were visible on DT. The main reason for not seeing a nodule on DT was small size (93.3%, ≤ 5 mm). DT revealed a substantial number of malignant nodules (84.1%, 143/170). The proportion of malignant nodules among visible nodules on DT was significantly higher (64.7%, 143/221) than that on CT (41.1%, 170/414) (p 0.8, and the average detection rate for malignant nodules was 85% (210/246). The inter-session analysis of the AUC showed no significant differences among the readers, and the detection rate for malignant nodules did not differ across sessions. A slight improvement in reading times was observed. Most malignant nodules > 5 mm were visible on DT. As nodule detection performance was high from the initial session, DT may be readily applicable for radiology residents and board-certified radiologists.

  4. Digital tomosynthesis for evaluating metastatic lung nodules: Nodule visibility, learning curves, and reading times

    International Nuclear Information System (INIS)

    Lee, Kyung Hee; Goo, Jin Mo; Lee, Sang Min; Park, Chang Min; Bahn, Young Eun; Kim, Hyung Jin; Song, Yong Sub; Hwang, Eui Jin

    2015-01-01

    To evaluate nodule visibility, learning curves, and reading times for digital tomosynthesis (DT). We included 80 patients who underwent computed tomography (CT) and DT before pulmonary metastasectomy. One experienced chest radiologist annotated all visible nodules on thin-section CT scans using computer-aided detection software. Two radiologists used CT as the reference standard and retrospectively graded the visibility of nodules on DT. Nodule detection performance was evaluated in four sessions of 20 cases each by six readers. After each session, readers were unblinded to the DT images by revealing the true-positive markings and were instructed to self-analyze their own misreads. Receiver-operating-characteristic curves were determined. Among 414 nodules on CT, 53.3% (221/414) were visible on DT. The main reason for not seeing a nodule on DT was small size (93.3%, < or = 5 mm). DT revealed a substantial number of malignant nodules (84.1%, 143/170). The proportion of malignant nodules among visible nodules on DT was significantly higher (64.7%, 143/221) than that on CT (41.1%, 170/414) (p < 0.001). Area under the curve (AUC) values at the initial session were > 0.8, and the average detection rate for malignant nodules was 85% (210/246). The inter-session analysis of the AUC showed no significant differences among the readers, and the detection rate for malignant nodules did not differ across sessions. A slight improvement in reading times was observed. Most malignant nodules > 5 mm were visible on DT. As nodule detection performance was high from the initial session, DT may be readily applicable for radiology residents and board-certified radiologists.

  5. Digital tomosynthesis for evaluating metastatic lung nodules: Nodule visibility, learning curves, and reading times

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Hee; Goo, Jin Mo; Lee, Sang Min; Park, Chang Min; Bahn, Young Eun; Kim, Hyung Jin; Song, Yong Sub; Hwang, Eui Jin [Dept. of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul (Korea, Republic of)

    2015-04-15

    To evaluate nodule visibility, learning curves, and reading times for digital tomosynthesis (DT). We included 80 patients who underwent computed tomography (CT) and DT before pulmonary metastasectomy. One experienced chest radiologist annotated all visible nodules on thin-section CT scans using computer-aided detection software. Two radiologists used CT as the reference standard and retrospectively graded the visibility of nodules on DT. Nodule detection performance was evaluated in four sessions of 20 cases each by six readers. After each session, readers were unblinded to the DT images by revealing the true-positive markings and were instructed to self-analyze their own misreads. Receiver-operating-characteristic curves were determined. Among 414 nodules on CT, 53.3% (221/414) were visible on DT. The main reason for not seeing a nodule on DT was small size (93.3%, < or = 5 mm). DT revealed a substantial number of malignant nodules (84.1%, 143/170). The proportion of malignant nodules among visible nodules on DT was significantly higher (64.7%, 143/221) than that on CT (41.1%, 170/414) (p < 0.001). Area under the curve (AUC) values at the initial session were > 0.8, and the average detection rate for malignant nodules was 85% (210/246). The inter-session analysis of the AUC showed no significant differences among the readers, and the detection rate for malignant nodules did not differ across sessions. A slight improvement in reading times was observed. Most malignant nodules > 5 mm were visible on DT. As nodule detection performance was high from the initial session, DT may be readily applicable for radiology residents and board-certified radiologists.

  6. CT findings of thymic tumors

    International Nuclear Information System (INIS)

    Chung, Ho Son; Lee, Sang Jin; Hwang, Mi Soo; Cho, Kil Ho; Chang, Jae Chun; Park, Bok Hwan

    1991-01-01

    A CT scan can make accurate diagnoses of most thymic masses by assessing their size, shape, and internal architecture and is especially effective in detecting pleural implants, mediastinal involvement, and pulmonary parenchymal invasion in malignant thymoma. The authors analyzed the CT findings of 10 histologically-proven thymic masses from 1983 to 1990 in Yeungnam University Hospital. There were 10 cases of thymic masses in the anterior mediastinum consisting of 6 benign, 3 invasive thymomas, and one thymolipoma, while myasthenia gravis was associated with 2 cases of benign thymomas and with one case of invasive thymomas. The CT findings of the benign thymomas (6 cases) were well-defined, bordered, round-or oval-shaped masses with a well-preserved fat plane between the thymic mass and mediastinal great vessels, with no evidence of pleural implants and lung parenchymal invasion. The CT findings of the invasive thymomas (3 cases) were irregular, marginated lobular masses with obliteration of the fat plane between the thymic mass and surrounding great vessels, with evidence of local invasion such as extension to A-P window and mass effect to bronchus. Irregular pleural thickening due to pleural metastasis, multiple metastatic lung parenchymal nodules, and multiple mediastinal lymph node enlargement were also seen in the invasive thymomas. One case of thymolipoma showed an approximately 20cm-size, well-defined fat density mass containing internal septations

  7. CT findings of thymic tumors

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Ho Son; Lee, Sang Jin; Hwang, Mi Soo; Cho, Kil Ho; Chang, Jae Chun; Park, Bok Hwan [College of Medicine, Yeungnam University, Daegu (Korea, Republic of)

    1991-05-15

    A CT scan can make accurate diagnoses of most thymic masses by assessing their size, shape, and internal architecture and is especially effective in detecting pleural implants, mediastinal involvement, and pulmonary parenchymal invasion in malignant thymoma. The authors analyzed the CT findings of 10 histologically-proven thymic masses from 1983 to 1990 in Yeungnam University Hospital. There were 10 cases of thymic masses in the anterior mediastinum consisting of 6 benign, 3 invasive thymomas, and one thymolipoma, while myasthenia gravis was associated with 2 cases of benign thymomas and with one case of invasive thymomas. The CT findings of the benign thymomas (6 cases) were well-defined, bordered, round-or oval-shaped masses with a well-preserved fat plane between the thymic mass and mediastinal great vessels, with no evidence of pleural implants and lung parenchymal invasion. The CT findings of the invasive thymomas (3 cases) were irregular, marginated lobular masses with obliteration of the fat plane between the thymic mass and surrounding great vessels, with evidence of local invasion such as extension to A-P window and mass effect to bronchus. Irregular pleural thickening due to pleural metastasis, multiple metastatic lung parenchymal nodules, and multiple mediastinal lymph node enlargement were also seen in the invasive thymomas. One case of thymolipoma showed an approximately 20cm-size, well-defined fat density mass containing internal septations.

  8. CT diagnosis of cystic echinococcosis in pelvis

    International Nuclear Information System (INIS)

    Liu Wenya; Li Li; Xing Yan; Xie Jingxia

    2003-01-01

    Objective: To analyze the CT findings of pelvic cystic echinococcosis, and to assess the value of CT examination. Methods: Twenty-one cases of pelvic cystic echinococcosis, confirmed by clinical and pathological results, underwent CT scanning. CT characters were analyzed and compared with pathology. Results: Simple cystic echinococcosis appeared as single or multiple cystic lesions with round or oval shape, smooth boundary, and no enhancement after contrast medium administration in 3 cases; Different number and size of daughter cysts were detected inside the lesion in 17 cases; Ruptured lesions showed 'double wall', 'water snake', or 'flow ribbon' signs in 4 cases; Increase density of contents and enhanced cystic wall were demonstrated in 2 cases with companied infections. In 8 cases, calcification occurred on the cystic wall or extended inside the content. Conclusion: CT could accurately demonstrate the location, appearance, internal structure, and adjacent situation of the cystic echinococcosis, providing valuable information for correct diagnosis and treatment

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-05-01

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

  10. CT and sonographic diagnosis of retained surgical sponge

    International Nuclear Information System (INIS)

    Matsumoto, Syunro; Aikawa, Hisayuki; Miyake, Hidetoshi; Mori, Hiromu; Maeda, Tohru; Nishimura, Hiro; Monzen, Yoshio; Ashizawa, Akira; Isomoto, Ichiro.

    1990-01-01

    Seven cases of pathologically proven retained surgical sponge were reviewed and classified into four types, depending on CT and US findings. CT showed a mass with tiny gas bubbles, and sonogram showed an echogenic area with strong posterior shadow (Type I). CT showed an irregular high density mass with no gas bubble, and sonogram showed an echogenic area with strong posterior shadow (Type II). CT showed a low density mass with irregular internal high density areas, and somogram showed a cystic mass with zigzag internal components (Type III). CT showed an eliptic high density mass with low density area internally. Judging from the experiment and operative findings, these patterns were decided by the number and status of the gauze, volume of the exudate and hematoma, and status of the granulation. The author concludes that these characteristic CT and US findings, together with a history of surgery, permit the correct diagnosis of retained surgical sponge. (author)

  11. Abdominal lymphadenopathy in tuberculosis and lymphoma: Differentiation with CT

    International Nuclear Information System (INIS)

    Shin, Yong Moon; Choi, Byung Ihn; Han, Joon Koo; Han, Man Chung; Song, Chi Sung; Yang, Seoung Oh

    1993-01-01

    Tuberculosis and lymphoma, these 2 dieases can present with lymphadenopathy in anywhere of the body. Therefore differentiation of tuberculosis from lymphoma is often difficult. CT scans of 17 patients with tuberculosis and 23 patients with lymphoma were retrospectively reviewed to evaluate the efficacy of CT scans in differentating adenopathy between tuberculosis and lymphoma. All the patients underwent abdominal CT scans with contrast enhancement before treatment. The size, internal architecture, distribution of lymph nodes, and associated findings on CT scans were analyzed. As compared with lymphoma, tuberculous lymphadenopathy showed 1) female preponderance (65%), 2) predilection for percolative lymph nodes (47%), 3) internal low attenuation in lymph nodes (82%), 4) cold abscess formation (24%). Characteristics of lymphoma on CT scans include 1) male preponderance (78%), 2) conglomeration of lymph nodes (39%), 3) homogeneous internal lymph node structure (83%). These results suggest that evaluation of the cahracteristics of lymphadenopathy on CT scans is helpful for differentiating between tuberculousis and lymphoma

  12. Spinal CT scan, 1

    International Nuclear Information System (INIS)

    Nakagawa, Hiroshi

    1982-01-01

    Methods of CT of the cervical and thoracic spines were explained, and normal CT pictures of them were described. Spinal CT was evaluated in comparison with other methods in various spinal diseases. Plain CT revealed stenosis due to spondylosis or ossification of posterior longitudinal ligament and hernia of intervertebral disc. CT took an important role in the diagnosis of spinal cord tumors with calcification and destruction of the bone. CT scan in combination with other methods was also useful for the diagnosis of spinal injuries, congenital anomalies and infections. (Ueda, J.)

  13. Normal mediastinal and hilar lymph nodes evaluated by 5 mm slice bolus injection CT scan

    International Nuclear Information System (INIS)

    Yamamoto, Takako; Tsukada, Hiroshi; Koizumi, Naoya; Akita, Shinichi; Oda, Junichi; Sakai, Kunio

    1995-01-01

    We evaluated the number and size of normal mediastinal and hilar lymph nodes by 5 mm slice bolus injection CT (12 patients), compared with 10 mm slice CT (12 patients). More lymph nodes were clearly demonstrated by 5 mm slice CT than by 10 mm slice CT. Especially left-sided tracheobronchial (no.4), subaortic (no.5), subcarinal (no.7) and hilar lymph nodes were clearly visible. We concluded 5 mm slice bolus injection CT was useful to evaluate mediastinal and hilar lymph nodes. (author)

  14. Body packers on your examination table: How helpful are plain x-ray images? A definitive low-dose CT protocol as a diagnosis tool for body packers.

    Science.gov (United States)

    Schulz, B; Grossbach, A; Gruber-Rouh, T; Zangos, S; Vogl, Th J; Eichler, K

    2014-12-01

    To analyze the clinical value and radiation dose of plain x-rays and CT in examining patients suspected of ingesting drug-filled packets. Thirty-eight patients with suspected internal concealment of drug-filled packets who were examined with plain x-rays or CT or both were included in the study. CT studies were performed using low-dose and standard-dose techniques. All radiographic images were analysed by two radiologists regarding identification of the packets and estimating the effective radiation dose from standard- and low-dose CT versus conventional x-ray examinations. Descriptive calculations were made regarding the number and density of packs and radiation dosage. The diagnostic performance of both radiologists with standard- and low-dose CT was calculated by analysing differences in the mean number of packs found. Thirty-one patients were positively identified as body packers with an average of 13 packs (min: n = 1, max: n = 58, total: n = 390); seven patients were not concealing drug packets. X-ray images were taken of 24 patients prior to CT, thus allowing a direct comparison between the two methods. The correct diagnosis was made in 42%, in 33% the radiologists were uncertain, and in 25% of drug packets were either not or wrongly identified. X-ray imaging had a positive predictive value of 20% with a negative predictive value of 81%. A total of 55 CT examinations were performed on all patients with a mean effective dose of 2 mSv (low dose) versus 9.3 mSv (standard dose). The visibility of packets on low-dose CT images compared to high-dose CT was not reduced: the radiologists identified 385 and 381 of the packets, respectively, with no difference regarding the examination technique (p = 0.24 and p = 0.253, respectively). The radiodensity of all drug-filled packets at CT ranged from 26-292 HU (mean 181.2 HU). X-ray imaging of supposed body packers leads to a significant risk of diagnostic errors and additional need for CT. Instead, a single abdominal low

  15. Researching in education findings visibility: How Cubans are doing?

    Directory of Open Access Journals (Sweden)

    Torres, Paúl A.

    2012-07-01

    Full Text Available The paper presents an analysis of Cuban educational research visibility by considering international ranking positioning of intellectual production in the field of education. A case study is conducted with outstanding Cuban educational researchers comparing their results with other prestigious professionals in the continent. Finally, new basic resources are proposed and explained for improving Bibliometric indicators by taking advantage of Google Scholar potentials in favoring international ranking positioning.

  16. CT appearance of splenosis

    Energy Technology Data Exchange (ETDEWEB)

    Mendelson, D.S.; Cohen, B.A.; Armas, R.R.

    1982-12-01

    Splenosis is an unusual complication of splenic trauma. The computed tomographic (CT) appearance of splenosis is described. One should consider this diagnosis when faced with a history of splenic trauma and multiple round or oval masses at CT.

  17. CT appearance of splenosis

    International Nuclear Information System (INIS)

    Mendelson, D.S.; Cohen, B.A.; Armas, R.R.

    1982-01-01

    Splenosis is an unusual complication of splenic trauma. The computed tomographic (CT) appearance of splenosis is described. One should consider this diagnosis when faced with a history of splenic trauma and multiple round or oval masses at CT

  18. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ... prescribed procedure with your doctor, the medical facility staff and/or your insurance provider to get a ...

  19. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ... prescribed procedure with your doctor, the medical facility staff and/or your insurance provider to get a ...

  20. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ... prescribed procedure with your doctor, the medical facility staff and/or your insurance provider to get a ...

  1. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... cavities (ventricles) in patients with hydrocephalus . diseases or malformations of the skull. CT scanning is also performed ... biopsy ) from the brain. assess aneurysms or arteriovenous malformations through a technique called CT angiography. For more ...

  2. Abdominal and Pelvic CT

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    Full Text Available ... CT scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector ... Safety page for more information about radiation dose. Women should always inform their physician and x-ray ...

  3. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... CT scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector ... Safety page for more information about radiation dose. Women should always inform their physician and x-ray ...

  4. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... CT scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector ... Safety page for more information about radiation dose. Women should always inform their physician and x-ray ...

  5. Abdominal and Pelvic CT

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    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... preferable over CT scanning. top of page Additional Information and Resources RTAnswers.org: Radiation Therapy for Bladder ...

  6. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... CT of the Sinuses? CT is usually the first test ordered when a sinus tumor is suspected. ... Radiology (ACR) and the Radiological Society of North America (RSNA), comprising physicians with expertise in several radiologic ...

  7. Abdominal and Pelvic CT

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    Full Text Available ... CT scanner or may be over the weight limit—usually 450 pounds—for the moving table. CT ... type your comment or suggestion into the following text box: Comment: E-mail: Area code: Phone no: ...

  8. Abdominal and Pelvic CT

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    Full Text Available ... microphone. top of page How does the procedure work? In many ways CT scanning works very much ... CT scan, an experienced radiologist can diagnose many causes of abdominal pain or injury from trauma with ...

  9. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... the scanning. Any motion, whether breathing or body movements, can lead to artifacts on the images. This ... clinical problems. CT is less sensitive to patient movement than MRI. CT can be performed if you ...

  10. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... the scanning. Any motion, whether breathing or body movements, can lead to artifacts on the images. This ... clinical problems. CT is less sensitive to patient movement than MRI. CT can be performed if you ...

  11. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... the scanning. Any motion, whether breathing or body movements, can lead to artifacts on the images. This ... clinical problems. CT is less sensitive to patient movement than MRI. CT can be performed if you ...

  12. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... about tumors of the nasal cavity and sinuses. plan for surgery by defining anatomy. top of page ... for sinusitis. CT of the sinuses can help plan the safest and most effective surgery. CT of ...

  13. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view ... Safety Images related to Computed Tomography (CT) - Head Videos related to Computed Tomography (CT) - Head Sponsored by ...

  14. Abdominal and Pelvic CT

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    Full Text Available ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view ... related to Computed Tomography (CT) - Abdomen and Pelvis Videos related to Computed Tomography (CT) - Abdomen and Pelvis ...

  15. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... be viewed on a computer monitor, printed on film or transferred to a CD or DVD. CT ... distinguished from one another on an x-ray film or CT electronic image. In a conventional x- ...

  16. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... be viewed on a computer monitor, printed on film or transferred to a CD or DVD. CT ... distinguished from one another on an x-ray film or CT electronic image. In a conventional x- ...

  17. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... be viewed on a computer monitor, printed on film or transferred to a CD or DVD. CT ... distinguished from one another on an x-ray film or CT electronic image. In a conventional x- ...

  18. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... of CT Scanning of the Abdomen and Pelvis? What is CT Scanning of the Abdomen/Pelvis? Computed ... soft tissues and blood vessels. top of page What are some common uses of the procedure? This ...

  19. Computed Tomography (CT) -- Head

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    Full Text Available ... microphone. top of page How does the procedure work? In many ways CT scanning works very much ... head CT scanning. Manufacturers of intravenous contrast indicate mothers should not breastfeed their babies for 24-48 ...

  20. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... over time. top of page What are the benefits vs. risks? Benefits A CT scan is one of the safest ... scanning is painless, noninvasive and accurate. A major advantage of CT is its ability to image bone, ...

  1. Abdominal and Pelvic CT

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    Full Text Available ... over time. top of page What are the benefits vs. risks? Benefits Viewing a CT scan, an experienced radiologist can ... scanning is painless, noninvasive and accurate. A major advantage of CT is its ability to image bone, ...

  2. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... as a CT or CAT scan, is a diagnostic medical test that, like traditional x-rays, produces ... particularly the lungs, abdomen, pelvis and bones. A diagnosis determined by CT scanning may eliminate the need ...

  3. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... as a CT or CAT scan, is a diagnostic medical test that, like traditional x-rays, produces ... medical device of any kind, unlike MRI. A diagnosis determined by CT scanning may eliminate the need ...

  4. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... CT scanning. top of page Additional Information and Resources RTAnswers.org: Radiation Therapy for Bladder Cancer Radiation ... Image Gallery Patient undergoing computed tomography (CT) scan View full size with caption Pediatric Content Some imaging ...

  5. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... CT) of the abdomen and pelvis is a diagnostic imaging test used to help detect diseases of ... as a CT or CAT scan, is a diagnostic medical test that, like traditional x-rays, produces ...

  6. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... benefits vs. risks? Benefits A CT scan is one of the safest means of studying the sinuses. ... CT scanning provides very detailed images of many types of tissue as well as the lungs, bones, ...

  7. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... sometimes compared to looking into a loaf of bread by cutting the loaf into thin slices. When ... actual CT scanning is performed. Depending on the type of CT scan, the machine may make several ...

  8. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... can be performed if you have an implanted medical device of any kind, unlike MRI. CT imaging ...

  9. Abdominal and Pelvic CT

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    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... can be performed if you have an implanted medical device of any kind, unlike MRI. CT imaging ...

  10. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... top of page What are the benefits vs. risks? Benefits CT scanning is painless, noninvasive and accurate. ... CT scans should have no immediate side effects. Risks There is always a slight chance of cancer ...

  11. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... top of page What are the benefits vs. risks? Benefits Viewing a CT scan, an experienced radiologist ... CT scans should have no immediate side effects. Risks There is always a slight chance of cancer ...

  12. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... top of page What are the benefits vs. risks? Benefits A CT scan is one of the ... CT scans should have no immediate side effects. Risks There is always a slight chance of cancer ...

  13. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ... membranes covering the brain. top of page Additional Information and Resources RTAnswers.org Radiation Therapy for Brain ...

  14. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ... for the moving table. top of page Additional Information and Resources RTAnswers.org Radiation Therapy for Head ...

  15. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Stroke Brain Tumors Computer Tomography (CT) Safety During Pregnancy Head and Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Computed Tomography (CT) - ...

  16. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... air-filled spaces within the bones of the face surrounding the nasal cavity. CT scanning is painless, ... and blood vessels. A CT scan of the face produces images that also show a patient's paranasal ...

  17. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... CT scanner is typically a large, box-like machine with a hole, or short tunnel, in the ... Then, the table will move slowly through the machine as the actual CT scanning is performed. Depending ...

  18. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... CT scanner is typically a large, box-like machine with a hole, or short tunnel, in the ... Then, the table will move slowly through the machine as the actual CT scanning is performed. Depending ...

  19. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... CT scanner is typically a large, box-like machine with a hole, or short tunnel, in the ... Then, the table will move slowly through the machine as the actual CT scanning is performed. Depending ...

  20. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... Then, the table will move slowly through the machine as the actual CT scanning is performed. Depending ...

  1. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... Then, the table will move slowly through the machine as the actual CT scanning is performed. Depending ...

  2. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... Then, the table will move slowly through the machine as the actual CT scanning is performed. Depending ...

  3. Understanding and Approaching Muslim Visibilities

    DEFF Research Database (Denmark)

    Schmidt, Garbi

    2011-01-01

    Within Western nation-states such as Denmark, Islamic identities are often seen as inherently and divergently visible, an aspect that some argue is detrimental to the secular nation-state. From a research perspective, one way to nuance this position is by focusing on groups of 'invisible' Muslims...

  4. Early Learning Theories Made Visible

    Science.gov (United States)

    Beloglovsky, Miriam; Daly, Lisa

    2015-01-01

    Go beyond reading about early learning theories and see what they look like in action in modern programs and teacher practices. With classroom vignettes and colorful photographs, this book makes the works of Jean Piaget, Erik Erikson, Lev Vygotsky, Abraham Maslow, John Dewey, Howard Gardner, and Louise Derman-Sparks visible, accessible, and easier…

  5. Non-Euclidean visibility problems

    Indian Academy of Sciences (India)

    FERNANDO CHAMIZO. Departamento de Matemáticas, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain. MS received 14 November 2005. Abstract. We consider the analog of visibility problems in hyperbolic plane (repre- sented by Poincaré half-plane model H), replacing the standard lattice Z ...

  6. Are naked singularities really visible

    Energy Technology Data Exchange (ETDEWEB)

    Calvani, M [Padua Univ. (Italy). Ist. di Astronomia; De Felice, F [Alberta Univ., Edmonton (Canada); Nobili, L [Padua Univ. (Italy). Ist. di Fisica

    1978-12-09

    The question whether a Kerr naked singularity is actually visible from infinity is investigated; it is shown that in fact any signal which could be emitted from the singularity is infinitely red-shifted. This implies that naked singularities would be indistinguishable from a black hole.

  7. Visible Machine Learning for Biomedicine.

    Science.gov (United States)

    Yu, Michael K; Ma, Jianzhu; Fisher, Jasmin; Kreisberg, Jason F; Raphael, Benjamin J; Ideker, Trey

    2018-06-14

    A major ambition of artificial intelligence lies in translating patient data to successful therapies. Machine learning models face particular challenges in biomedicine, however, including handling of extreme data heterogeneity and lack of mechanistic insight into predictions. Here, we argue for "visible" approaches that guide model structure with experimental biology. Copyright © 2018. Published by Elsevier Inc.

  8. CT of the knee

    International Nuclear Information System (INIS)

    Ghelman, B.

    1987-01-01

    CT can be combined with arthrography of the knee to study the following abnormalities: meniscal tears and cysts, synovial plicae, chondromalacia patellae, and osteochondritis dissecans. The CT-arthrogram images present abnormalities in a manner that resembles the ''in situ'' surgical findings, allowing management decisions to be made with greater confidence. The CT techniques for imaging the knee after arthrography are discussed, as is the use of plain CT

  9. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) ... are the limitations of Children's CT? What is Children's CT? Computed tomography, more commonly known as a ...

  10. CT of laryngotracheal trauma

    International Nuclear Information System (INIS)

    Lupetin, A.R.; Daffner, R.H.

    1991-01-01

    This paper evaluates the usefulness of CT for the diagnosis of traumatic laryngotracheal abnormalities. The authors retrospectively evaluated the neck CT studies of 50 patients (36 males, 14 females; age range, 16-75 years) who presented to a level I trauma center after suffering a blunt or penetrating laryngotracheal injury. CT results were correlated with endoscopic or surgical findings in 43 cases. Three groups emerge. CT positive: hyloid bone or laryngotracheal cartilage injury; CT positive: soft-tissue injury only; and CT negative. In group 1, CT demonstrated all bony or cartilaginous injuries proved at surgery or suggested at endoscopy. CT failed to demonstrate laryngotracheal separation in 1 case. In group 2, CT demonstrated all soft-tissue injuries suggested at endoscopy. In group 3, CT findings agreed with those of endoscopy in 7 cases, but minor soft-tissue findings seen at endoscopy were missed in 3 cases. Seven patients were studied only with CT. Ct is an accurate technique for detecting bony or cartilaginous laryngotracheal traumatic abnormalities. However, laryngotracheal separation and minor soft-tissue injuries can be missed

  11. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses Computed tomography (CT) of the sinuses uses special x-ray equipment ... story here Images × Image Gallery Patient undergoing computed tomography (CT) scan. View full size with caption Pediatric Content ...

  12. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head Computed tomography (CT) of the head uses special x-ray equipment ... story here Images × Image Gallery Patient undergoing computed tomography (CT) scan. View full size with caption Pediatric Content ...

  13. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams Blood Clots CT Perfusion of the Head CT Angiography ( ...

  14. WE-G-209-02: CT

    International Nuclear Information System (INIS)

    Kofler, J.

    2016-01-01

    Digital radiography, CT, PET, and MR are complicated imaging modalities which are composed of many hardware and software components. These components work together in a highly coordinated chain of events with the intent to produce high quality images. Acquisition, processing and reconstruction of data must occur in a precise way for optimum image quality to be achieved. Any error or unexpected event in the entire process can produce unwanted pixel intensities in the final images which may contribute to visible image artifacts. The diagnostic imaging physicist is uniquely qualified to investigate and contribute to resolution of image artifacts. This course will teach the participant to identify common artifacts found clinically in digital radiography, CT, PET, and MR, to determine the causes of artifacts, and to make recommendations for how to resolve artifacts. Learning Objectives: Identify common artifacts found clinically in digital radiography, CT, PET and MR. Determine causes of various clinical artifacts from digital radiography, CT, PET and MR. Describe how to resolve various clinical artifacts from digital radiography, CT, PET and MR.

  15. WE-G-209-02: CT

    Energy Technology Data Exchange (ETDEWEB)

    Kofler, J. [Mayo Clinic (United States)

    2016-06-15

    Digital radiography, CT, PET, and MR are complicated imaging modalities which are composed of many hardware and software components. These components work together in a highly coordinated chain of events with the intent to produce high quality images. Acquisition, processing and reconstruction of data must occur in a precise way for optimum image quality to be achieved. Any error or unexpected event in the entire process can produce unwanted pixel intensities in the final images which may contribute to visible image artifacts. The diagnostic imaging physicist is uniquely qualified to investigate and contribute to resolution of image artifacts. This course will teach the participant to identify common artifacts found clinically in digital radiography, CT, PET, and MR, to determine the causes of artifacts, and to make recommendations for how to resolve artifacts. Learning Objectives: Identify common artifacts found clinically in digital radiography, CT, PET and MR. Determine causes of various clinical artifacts from digital radiography, CT, PET and MR. Describe how to resolve various clinical artifacts from digital radiography, CT, PET and MR.

  16. Marketing cardiac CT programs.

    Science.gov (United States)

    Scott, Jason

    2010-01-01

    There are two components of cardiac CT discussed in this article: coronary artery calcium scoring (CACS) and coronary computed tomography angiography (CCTA).The distinctive advantages of each CT examination are outlined. In order to ensure a successful cardiac CT program, it is imperative that imaging facilities market their cardiac CT practices effectively in order to gain a competitive advantage in this valuable market share. If patients receive quality care by competent individuals, they are more likely to recommend the facility's cardiac CT program. Satisfied patients will also be more willing to come back for any further testing.

  17. Ultraviolet, Visible, and Fluorescence Spectroscopy

    Science.gov (United States)

    Penner, Michael H.

    Spectroscopy in the ultraviolet-visible (UV-Vis) range is one of the most commonly encountered laboratory techniques in food analysis. Diverse examples, such as the quantification of macrocomponents (total carbohydrate by the phenol-sulfuric acid method), quantification of microcomponents, (thiamin by the thiochrome fluorometric procedure), estimates of rancidity (lipid oxidation status by the thiobarbituric acid test), and surveillance testing (enzyme-linked immunoassays), are presented in this text. In each of these cases, the analytical signal for which the assay is based is either the emission or absorption of radiation in the UV-Vis range. This signal may be inherent in the analyte, such as the absorbance of radiation in the visible range by pigments, or a result of a chemical reaction involving the analyte, such as the colorimetric copper-based Lowry method for the analysis of soluble protein.

  18. A contrast enhancement and scanning techniques for CT angiography of head and neck. One phase injection method for simultaneous imaging of vessels and tumor

    International Nuclear Information System (INIS)

    Morita, Yasuhiko; Indo, Hiroko; Noikura, Takenori

    1999-01-01

    We report on a method of CT-Angiography useful for examining lesion of the head and neck using three-dimensional images and measured CT value. This study focused on some of the important blood vessels in the head and neck. The aim of this method was to obtain high-contrast enhancement for both vessels and tumors at same time. A total amount of 100 ml nonionic contrast media (Omnipaque 240, 240 mg iodine per milliliter, Daiichi seiyaku, Tokyo, Japan) was injected intravenously with a flow of 1.5 ml/sec. Spiral scans, 24 rotations with 24 seconds, were started at a time when remaining amount of contrast media had become 30 to 20 ml. All CT scans were performed using double speed spiral scan technique with a slice thickness of 2 to 3 mm and table speeds from 3 to 5 mm/rotation. The patients populations consisted of 9 men and 6 women who ranged in age from 37 to 85 years. Sixteen CT-angiography were performed according to this method. Mean CT values of major blood vessels were measured in order to find out threshold at the level of submandibular gland in 13 examinations for 12 subjects. Important vessels like the common, internal, and the external artery, internal and external jugular vein were clearly visible in all subjects. Three dimensional images of these vessels could also be reconstructed for 15 of the subjects. Mean CT values were 211 Hounsfield units (HU) and 209 HU for the right and left internal carotid artery, respectively, and 204 HU and 206 HU for the right and left external carotid artery, respectively. Mean CT values for right and left internal jugular vein were 195 HU and 194 HU respectively. Measured CT values at each important blood vessels showed this method could yields acceptable enhancements. Good enhancement effect of tumor and blood vessels in the same scan seems to be mutually incompatible. One very important trade-off is the early enhancement effect at blood vessels versus the late enhancement effect at tumors. The other important trade

  19. Chemical lasers in the visible

    International Nuclear Information System (INIS)

    Jones, C.R.; Broida, H.P.

    1974-01-01

    Since the beginning of the laser era in 1960, a continuing search for chemical lasers has been carried out. This quest has been influenced by the knowledge that many chemical reactions produce visible chemiluminescence and, therefore, partition some of the reaction products into emitting, electronically excited states. Such luminescence has been observed not only from low-pressure, gas-phase reactions, notably those of alkali metals and halogens, but also from a limited number of liquid-phase reactions. (U.S.)

  20. Computing Visible-Surface Representations,

    Science.gov (United States)

    1985-03-01

    Terzopoulos N00014-75-C-0643 9. PERFORMING ORGANIZATION NAME AMC ADDRESS 10. PROGRAM ELEMENT. PROJECT, TASK Artificial Inteligence Laboratory AREA A...Massachusetts Institute of lechnolog,. Support lbr the laboratory’s Artificial Intelligence research is provided in part by the Advanced Rtccarcl Proj...dynamically maintaining visible surface representations. Whether the intention is to model human vision or to design competent artificial vision systems

  1. Comparison of CT angiography and digital subtraction angiography in the evaluation of intracranial aneurysmal neck

    International Nuclear Information System (INIS)

    Kim, Yoo Kyung; Baik, Seung Kug; Shin, Mi Jeong; Choi, Han Yong

    2001-01-01

    To compare the usefulness of three-dimensional multislice CT angiography(CTA) and digital subtraction angiography (DSA) in the evaluation of intracranial aneurysmal neck. Nineteen patients with intracranial aneurysm (23 cases) underwent DSA and subsequent CTA. Using a multislice CT scanner and the SSD(shaded surface display) technique, clipping, cutting and the MPR technique, three-dimensional images were obtained. These were (a) external, (b) internal, from the direction of the parent artery, (c) internal, from the direction of the aneurysmal dome, and (d) an aneurysmal cutting image. The CTA findings were retrospectively compared with the DSA images. Twenty aneurysms were small and three were large. In eleven cases aneurysm neck was small, in nine it was wide, and in three it was relatively wide. For aneurysmal neck evaluation, CTA was superior to DSA in six of nine wide-neck aneurysms and all three large-sized wide-neck aneurysms. In small neck aneurysms 8 of 11 cases and in relatively wide neck all 3 cases showed similarly good images by both modalities. Of the 23 cases demonstrated by four different images, 14 cases showed the best image in internal image from parent artery direction and 6 cases showed similarly good image in both aneurysmal cutting image and internal image from parent artery direction. In the evaluation of wide neck aneurysms, 7 of 9 cases showed the best image at internal image from parent artery direction, compared with other three different images. In two cases of aneurysms, calcification was visible in the aneurysmal wall, so it was difficult to evaluate the aneurysmal neck. CTA was superior to DSA in the evaluating the intracranial aneurysmal neck. CTA maybe an additional available modality to evaluate the aneurysmal neck which is difficult to detect by the DSA. And the information of intracranial aneurysmal neck through CTA will be of value in surgical and endovascular treatment

  2. Visibilidad internacional e impacto de la producción científica española en Sanidad Penitenciaria (2002-2011 International visibility and impact of the Spanish research on prison health (2002-2011

    Directory of Open Access Journals (Sweden)

    R. Ruíz-Pérez

    2013-06-01

    Impacto bajo (2,062 y son escasos los trabajos en revistas de primer nivel (Q1. Son pocos los trabajos con un promedio aceptable de citas en su área de conocimiento. El patrón de coautoría muestra aún un estado inmaduro de la investigación española en Sanidad Penitenciaria.Objective: This paper sets out to analyze the dissemination and impact of Spanish research published in international scientific journals on Prison Health over the last decade. Material and methods: Descriptive, longitudinal and retrospective analysis of scientific output. We used the Medline-Pubmed database as an information resource. We focus on the bibliometric aspects of journals, papers and authors using the indicators offered by the Web of Science, the Journal Citation Reports and the Essential Science Indicators. We identify the output of Spanish researchers, journals in which they are published, authors and main research fields. Results: From 2002 to 2011, Spanish researchers published 159 papers, that is, nearly 2% of the world's share in Prison Health. The publication profile is mainly in international journals with an average impact on JCR. The Revista Española de Sanidad Penitenciaria is the most productive journal (9.09%, although its role is not prominent. Only two authors can be considered as medium-high productive authors with 10 papers in the study time period. The co-authors network shows a dense network with 14 authors along with minor fragmented networks. As regards citations, 6 papers have been cited 15 or more times and only two can be considered as highly cited. Three main research fronts have been identified: infectious diseases, drugs and psychiatric-psychological problems. Conclusions: The Spanish research production on Prison Health represents a similar share of the world output similar to that of other disciplines (1.9%, although slightly lower (General Medicine represents 3.05%; Public Health, 2.38%; Psychiatry, 2.29%; Toxicology, 2.46%. It seems likely that this

  3. In vivo microCT imaging of rodent cerebral vasculature

    International Nuclear Information System (INIS)

    Seo, Youngho; Hasegawa, Bruce H; Hashimoto, Tomoki; Nuki, Yoshitsugu

    2008-01-01

    were visible with contrast-enhanced CT, but not with noncontrast CT. In conclusion, the CT-compatible immobilization device was useful for in vivo microCT imaging of intracranial blood and of vascular structures within and immediately adjacent to the rodent brain. The microCT imaging technique is also compatible with continuous administration of a conventional iodinated contrast agent (e.g. iopromide) and therefore does not require specialized small animal specific contrast agent that has comparatively long in vivo residence time. (note)

  4. In vivo microCT imaging of rodent cerebral vasculature

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Youngho; Hasegawa, Bruce H [Center for Molecular and Functional Imaging, Department of Radiology, University of California, San Francisco, CA 94143 (United States); Hashimoto, Tomoki; Nuki, Yoshitsugu [Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA 94143 (United States)], E-mail: youngho.seo@radiology.ucsf.edu

    2008-04-07

    arteries and major cerebral blood vessels were visible with contrast-enhanced CT, but not with noncontrast CT. In conclusion, the CT-compatible immobilization device was useful for in vivo microCT imaging of intracranial blood and of vascular structures within and immediately adjacent to the rodent brain. The microCT imaging technique is also compatible with continuous administration of a conventional iodinated contrast agent (e.g. iopromide) and therefore does not require specialized small animal specific contrast agent that has comparatively long in vivo residence time. (note)

  5. [Street Outreach Offices: visibility, invisibility, and enhanced visibility].

    Science.gov (United States)

    Hallais, Janaína Alves da Silveira; Barros, Nelson Filice de

    2015-07-01

    This article discusses care for street people from a socio-anthropological perspective, using participant observation conducted with a team from a street outreach project. Based on observations, street people are historically viewed as marginal and rarely obtain access to health services, thus making them invisible to the Brazilian Unified National Health System. Brazil's National Policy for the Homeless provides for their access to health care, but such care is not always guaranteed in practice, because health services and professionals have little experience in dealing with homeless persons. The study concludes that enhanced visibility is needed to ensure care for people living on the street, establishing a therapeutic bond that deconstructs stigmatizing practice.

  6. Beyond Language Equivalence on Visibly Pushdown Automata

    DEFF Research Database (Denmark)

    Srba, Jiri

    2009-01-01

    We study (bi)simulation-like preorder/equivalence checking on the class of visibly pushdown automata and its natural subclasses visibly BPA (Basic Process Algebra) and visibly one-counter automata. We describe generic methods for proving complexity upper and lower bounds for a number of studied...... preorders and equivalences like simulation, completed simulation, ready simulation, 2-nested simulation preorders/equivalences and bisimulation equivalence. Our main results are that all the mentioned equivalences and preorders are EXPTIME-complete on visibly pushdown automata, PSPACE-complete on visibly...... one-counter automata and P-complete on visibly BPA. Our PSPACE lower bound for visibly one-counter automata improves also the previously known DP-hardness results for ordinary one-counter automata and one-counter nets. Finally, we study regularity checking problems for visibly pushdown automata...

  7. Gastropod shell size and architecture influence the applicability of methods used to estimate internal volume.

    Science.gov (United States)

    Ragagnin, Marilia Nagata; Gorman, Daniel; McCarthy, Ian Donald; Sant'Anna, Bruno Sampaio; de Castro, Cláudio Campi; Turra, Alexander

    2018-01-11

    Obtaining accurate and reproducible estimates of internal shell volume is a vital requirement for studies into the ecology of a range of shell-occupying organisms, including hermit crabs. Shell internal volume is usually estimated by filling the shell cavity with water or sand, however, there has been no systematic assessment of the reliability of these methods and moreover no comparison with modern alternatives, e.g., computed tomography (CT). This study undertakes the first assessment of the measurement reproducibility of three contrasting approaches across a spectrum of shell architectures and sizes. While our results suggested a certain level of variability inherent for all methods, we conclude that a single measure using sand/water is likely to be sufficient for the majority of studies. However, care must be taken as precision may decline with increasing shell size and structural complexity. CT provided less variation between repeat measures but volume estimates were consistently lower compared to sand/water and will need methodological improvements before it can be used as an alternative. CT indicated volume may be also underestimated using sand/water due to the presence of air spaces visible in filled shells scanned by CT. Lastly, we encourage authors to clearly describe how volume estimates were obtained.

  8. Interactive machine learning for postprocessing CT images of hardwood logs

    Science.gov (United States)

    Erol Sarigul; A. Lynn Abbott; Daniel L. Schmoldt

    2003-01-01

    This paper concerns the nondestructive evaluation of hardwood logs through the analysis of computed tomography (CT) images. Several studies have shown that the commercial value of resulting boards can be increased substantially if log sawing strategies are chosen using prior knowledge of internal log defects. Although CT imaging offers a potential means of obtaining...

  9. CT Image Sequence Processing For Wood Defect Recognition

    Science.gov (United States)

    Dongping Zhu; R.W. Conners; Philip A. Araman

    1991-01-01

    The research reported in this paper explores a non-destructive testing application of x-ray computed tomography (CT) in the forest products industry. This application involves a computer vision system that uses CT to locate and identify internal defects in hardwood logs. The knowledge of log defects is critical in deciding whether to veneer or to saw up a log, and how...

  10. Investigation of vessel visibility of iterative reconstruction method in coronary computed tomography angiography using simulated vessel phantom

    International Nuclear Information System (INIS)

    Inoue, Takeshi; Uto, Fumiaki; Ichikawa, Katsuhiro; Hara, Takanori; Urikura, Atsushi; Hoshino, Takashi; Miura, Youhei; Terakawa, Syouichi

    2012-01-01

    Iterative reconstruction methods can reduce the noise of computed tomography (CT) images, which are expected to contribute to the reduction of patient dose CT examinations. The purpose of this study was to investigate impact of an iterative reconstruction method (iDose 4 , Philips Healthcare) on vessel visibility in coronary CT angiography (CTA) by using phantom studies. A simulated phantom was scanned by a CT system (iCT, Philips Healthcare), and the axial images were reconstructed by filtered back projection (FBP) and given a level of 1 to 7 (L1-L7) of the iterative reconstruction (IR). The vessel visibility was evaluated by a quantitative analysis using profiles across a 1.5-mm diameter simulated vessel as well as visual evaluation for multi planar reformation (MPR) images and volume rendering (VR) images in terms of the normalized-rank method with analysis of variance. The peak CT value of the profiles decreased with IR level and full width at half maximum of the profile also decreased with the IR level. For normalized-rank method, there was no statistical difference between FBP and L1 (20% dose reduction) for both MPR and VR images. The IR levels higher than L1 sacrificed the spatial resolution for the 1.5-mm simulated vessel, and their visual vessel visibilities were significantly inferior to that of the FBP. (author)

  11. Spinal CT scan, 2

    International Nuclear Information System (INIS)

    Nakagawa, Hiroshi

    1982-01-01

    Plain CT described fairly accurately the anatomy and lesions of the lumbar and sacral spines on their transverse sections. Since hernia of the intervertebral disc could be directly diagnosed by CT, indications of myelography could be restricted. Spinal-canal stenosis of the lumbar spine occurs because of various factors, and CT not only demonstrated the accurate size and morphology of bony canals, but also elucidated thickening of the joints and yellow ligament. CT was also useful for the diagnosis of tumors in the lumbar and sacral spines, visualizing the images of bone changes and soft tissues on the trasverse sections. But the diagnosis of intradural tumors required myelography and metrizamide CT. CT has become important for the diagnosis of spinal and spinal-cord diseases and for selection of the route of surgical arrival. (Chiba, N.)

  12. Computing visibility on terrains in external memory

    NARCIS (Netherlands)

    Haverkort, H.J.; Toma, L.; Zhuang, Yi

    2007-01-01

    We describe a novel application of the distribution sweeping technique to computing visibility on terrains. Given an arbitrary viewpoint v, the basic problem we address is computing the visibility map or viewshed of v, which is the set of points in the terrain that are visible from v. We give the

  13. CT of Mirizzi syndrome

    International Nuclear Information System (INIS)

    Yamamoto, Shinichiro; Fukushima, Keisuke; Ishihara, Kenji; Hirano, Yutaka; Sano, Kaizo

    1983-01-01

    PTC or ERCP findings of four cases of Mirizzi syndrome were demonstrated. They consisted of a smooth stricture of the common hepatic duct, curved impressions of the duct and dilatation of proximal biliary radicles. CT could visualize the impacted stone in the neck of the gallbladder, dilatation of proximal common hepatic and intrahepatic duct. Absence of the dilatation of distal common bile duct could also be confirmed by CT, thus the diagnosis of Mirizzi syndrome might be possible by CT. (author)

  14. Cystic thymic diseases: CT manifestations

    International Nuclear Information System (INIS)

    Song, Soon Young; Choi, Yo Won; Jeon, Eui Yong; Jeon, Seok Chol; Seo, Heung Suk; Hahm, Chang Kok

    1995-01-01

    To describe CT findings and differential points of cystic thymic lesions. We evaluated retrospectively total 19 masses with well marginated cystic lesions at thymic area on CT scans. They were 10 teratomas, 3 congenital thymic cysts, 2 multilocular thymic cysts(associated with thymoma and myasthenia gravis in each), 2 cysts Assciated with thymic Hodgkin's lymphomas an ectopic parathyroid cyst, and an infected thymic cyst. The radiological abnormalities evaluated were thickness of the wall, presence or abscene of septa, mural nodule, solid component, calcification and fat component. All three cases of congenital thymic cysts and an ectopic parathyroid cyst appeared as thin-walled unilocular cyst with homogeneous internal density and without identifiable solid component. In multilocular thymic cyst, there were thick wall and solid components(n =2), thick internal septa and calcifications(n = 1). The cysts of teratomas manifested thick walls(n = 9), internal septa(n = 4), calcifications(n = 6), fat components(n = 4), and solid components(n = 4). Cysts in Hodgkin's diseases appeared as multilocular or unilocular and had thick wall and septa without calcification. Infected thymic cyst presented with multilocular cystic mass with identifiable wall and septa, calcification, and solid components. The thymic diseases with cystic lesion include teratomas, congenital thymic cysts, multilocular thymic cysts, parathyroid cyst, and Hodgkin's disease. Congenital thymic cyst and ectopic parathyroid cyst are thin-walled unilocular cystic lesions. Cystic lesions associated with teratoma, Hodgkin's disease, and multilocular thymic cyst are thick-walled cystic lesions with or without solid component

  15. Visible Nulling Coronagraph Progress Report

    Science.gov (United States)

    Lyon, R. G.; Clampin, M.; Woodruff, R. A.; Vasudevan, G.; Thompson, P.; Petrone, P.; Madison, T.; Rizzo, M.; Melnick, G.; Tolls, V.

    2010-10-01

    We report on recent laboratory results with the NASA Goddard Space Flight Center Visible Nulling Coronagraph (VNC) testbed. We have achieved focal plane contrasts of 108 and approaching 109 at inner working angles of 2 λ/D and 4 λ/D, respectively. Results were obtained with a broadband source and 40 nm filter centered on 630 nm. A null control breadboard (NCB) was also developed to assess and quantify MEMS based deformable mirror technology (DM), and to develop and assess closed-loop null control algorithms. We have demonstrated closed-loop performance at 27 Hz.

  16. Coronary CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Dewey, Marc [Charite - Universitaetsmedizin Berlin (Germany). Inst. fuer Radiologie

    2009-07-01

    Coronary CT angiography has attained increasing scientific attention at academic institutions and has become a highly accurate diagnostic modality. Extending this knowledge into a practice setting is the purpose of 'Coronary CT Angiography'. This book will assist you in integrating cardiac CT into your daily practice, while also giving an overview of the current technical status and applications. The specific features of scanners from all four main vendors are also presented providing an objective overview of noninvasive coronary angiography using CT. (orig.)

  17. Head CT scan

    Science.gov (United States)

    ... scan - orbits; CT scan - sinuses; Computed tomography - cranial; CAT scan - brain ... head size in children Changes in thinking or behavior Fainting Headache, when you have certain other signs ...

  18. A short comparison between mT2 and mCT

    International Nuclear Information System (INIS)

    Serna, Mario

    2008-01-01

    We compare m T2 with m CT ; both are kinematic variables designed to find relationships between masses of pair-produced new states with symmetric decay chains. We find that for massless visible particles m CT equals m T2 in a particular limit. We identify advantages and disadvantages to the use of each variable. Tovey's paper on m CT also introduced a powerful concept of extracting mass information from an analysis at intermediate stages of a symmetric decay chain. We suggest that m T2 is a better tool for performing this analysis than m CT due to m T2 's better properties under initial state radiation.

  19. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) is a fast, painless exam that uses ... of Children's CT? What is Children's CT? Computed tomography, more commonly known as a CT or CAT ...

  20. Branchial cleft anomalies: CT evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Seok, Eul Hye; Park, Chan Sup [College of Medicine, Inha University, Seongnam (Korea, Republic of)

    1994-04-15

    The purpose of this paper is to describe the CT findings of a variety of branchial cleft anomalies in the head and neck area. We reviewed the CT findings of 16 patients with neck lesion pathologically proved as branchial cleft anomalies. There were two first and 12 second branchial cleft cysts, one first and one second branchial cleft sinuses. Two cases of first branchial cleft cysts were manifested as thin-walled, cystic masses at auricular area. One first branchial cleft sinus was an external opening type and manifested as an ill-defined, enhancing solid lesion at posterior auricular area. All 12 cases of second branchial cleft cysts demonstrated a typical location, displacing the sternocleidomastoid muscle posteriorly, the carotid artery and internal jugular vein complex medially and the submandibular gland anteriorly. Eight cases of second branchial cleft cysts were seen as fluid-filled, round or ovoid-shaped cysts, and 3 cases of them were seen as irregular-shaped cysts. In one case, suppurative adenopathy with loss of soft tissue planes around the cyst was observed. One case of second branchial cleft sinus was manifested as a tubular-shaped, enhancing lesion at submental area and containing external opening site draining into the anterior border of the sternocleidomastoid muscle. We conclude that CT provides important diagnostic and therapeutic information in patients with a neck mass believed to be a branchial cleft anomaly, as it can differentiate various forms of the branchial anomalies by their characteristic location and shape.

  1. Branchial cleft anomalies: CT evaluation

    International Nuclear Information System (INIS)

    Seok, Eul Hye; Park, Chan Sup

    1994-01-01

    The purpose of this paper is to describe the CT findings of a variety of branchial cleft anomalies in the head and neck area. We reviewed the CT findings of 16 patients with neck lesion pathologically proved as branchial cleft anomalies. There were two first and 12 second branchial cleft cysts, one first and one second branchial cleft sinuses. Two cases of first branchial cleft cysts were manifested as thin-walled, cystic masses at auricular area. One first branchial cleft sinus was an external opening type and manifested as an ill-defined, enhancing solid lesion at posterior auricular area. All 12 cases of second branchial cleft cysts demonstrated a typical location, displacing the sternocleidomastoid muscle posteriorly, the carotid artery and internal jugular vein complex medially and the submandibular gland anteriorly. Eight cases of second branchial cleft cysts were seen as fluid-filled, round or ovoid-shaped cysts, and 3 cases of them were seen as irregular-shaped cysts. In one case, suppurative adenopathy with loss of soft tissue planes around the cyst was observed. One case of second branchial cleft sinus was manifested as a tubular-shaped, enhancing lesion at submental area and containing external opening site draining into the anterior border of the sternocleidomastoid muscle. We conclude that CT provides important diagnostic and therapeutic information in patients with a neck mass believed to be a branchial cleft anomaly, as it can differentiate various forms of the branchial anomalies by their characteristic location and shape

  2. A three-dimensional definition of nodal spaces on the basis of CT images showing enlarged nodes for pelvic radiotherapy

    International Nuclear Information System (INIS)

    Portaluri, Maurizio; Bambace, Santa; Perez, Celeste; Angone, Grazia

    2005-01-01

    Purpose: To demonstrate that margins of each pelvic chain may be derived by verifying the bony and soft tissue structures around abnormal nodes on computed tomography (CT) slices. Methods and Materials: Twenty consecutive patients (16 males, 4 females; mean age, 66 years; range, 43-80 years) with radiologic diagnosis of nodal involvement by histologically proved cervix carcinoma (two), rectum carcinoma (three), prostate carcinoma (four), lymphoma (five), penis carcinoma (one), corpus uteri carcinoma (one), bladder carcinoma (two), cutis tumor (one), and soft-tissue sarcoma (one) were retrospectively reviewed. One hundred CT scans showing 85 enlarged pelvic nodes were reviewed by two radiation oncologists (M.P., S.B.), and two radiologists (C.P., G.A.). Results: The more proximal structures to each enlarged node or group of nodes were thus recorded in a clockwise direction. Conclusion: According to their frequency and visibility, craniocaudal, anterior, lateral, posterior and medial margins of common iliac, external and internal iliac nodal chains, obturator and pudendal nodes, and deep and superficial inguinal nodes were derived from CT observations

  3. Infrared and Visible links for medical Body Sensor Networks

    OpenAIRE

    Lebas , C; Sahuguede , S; Julien-Vergonjanne , A; Combeau , P; Aveneau , L

    2018-01-01

    International audience; — Our previous studies focused on channel simulation and performance evaluation of optical wireless links for medical body sensor networks. This allowed us to increase our expertise in this field and to propose here a full optical wireless bidirectional system named as LiFi communication system for medical monitoring applications. The full duplex bidirectional communication is based on an infrared uplink and visible downlink. The studied scenario considers a patient we...

  4. The presence and progression of emphysema in COPD as determined by CT scanning and biomarker expression

    DEFF Research Database (Denmark)

    Coxson, Harvey O; Dirksen, Asger; Edwards, Lisa D

    2013-01-01

    Emphysema is a key contributor to airflow limitation in chronic obstructive pulmonary disease (COPD) and can be quantified using CT scanning. We investigated the change in CT lung density in a longitudinal, international cohort of patients with COPD. We also explored the potential relation between...... emphysema and patient characteristics, and investigated if certain circulating biomarkers were associated with decline in CT lung density....

  5. A new coding system for metabolic disorders demonstrates gaps in the international disease classifications ICD-10 and SNOMED-CT, which can be barriers to genotype-phenotype data sharing.

    Science.gov (United States)

    Sollie, Annet; Sijmons, Rolf H; Lindhout, Dick; van der Ploeg, Ans T; Rubio Gozalbo, M Estela; Smit, G Peter A; Verheijen, Frans; Waterham, Hans R; van Weely, Sonja; Wijburg, Frits A; Wijburg, Rudolph; Visser, Gepke

    2013-07-01

    Data sharing is essential for a better understanding of genetic disorders. Good phenotype coding plays a key role in this process. Unfortunately, the two most widely used coding systems in medicine, ICD-10 and SNOMED-CT, lack information necessary for the detailed classification and annotation of rare and genetic disorders. This prevents the optimal registration of such patients in databases and thus data-sharing efforts. To improve care and to facilitate research for patients with metabolic disorders, we developed a new coding system for metabolic diseases with a dedicated group of clinical specialists. Next, we compared the resulting codes with those in ICD and SNOMED-CT. No matches were found in 76% of cases in ICD-10 and in 54% in SNOMED-CT. We conclude that there are sizable gaps in the SNOMED-CT and ICD coding systems for metabolic disorders. There may be similar gaps for other classes of rare and genetic disorders. We have demonstrated that expert groups can help in addressing such coding issues. Our coding system has been made available to the ICD and SNOMED-CT organizations as well as to the Orphanet and HPO organizations for further public application and updates will be published online (www.ddrmd.nl and www.cineas.org). © 2013 WILEY PERIODICALS, INC.

  6. CT of pleural abnormalities

    International Nuclear Information System (INIS)

    Webb, W.R.

    1995-01-01

    Briefly discussed were CT diagnosis of pleural thickening, CT technique for examining the pleura or pleuro-pulmonary disease, diagnosis of pleural collections, diagnosis of pleural fluid abnormalities in patients with pneumonia, pleural neoplasms, malignant (diffuse) mesothelioma, metastases, local fibrous tumor of the pleura (benign mesothelioma) (21 refs.)

  7. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... over time. top of page What are the benefits vs. risks? Benefits CT scanning is painless, noninvasive and accurate. A ... bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams ...

  8. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... images or pictures of the inside of the body. The cross-sectional images generated during a CT scan can be reformatted ... of data to create two-dimensional cross-sectional images of your body, which are then displayed on a monitor. CT ...

  9. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... images or pictures of the inside of the body. The cross-sectional images generated during a CT scan can be reformatted ... of data to create two-dimensional cross-sectional images of your body, which are then displayed on a monitor. CT ...

  10. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... images or pictures of the inside of the body. The cross-sectional images generated during a CT scan can be reformatted ... of data to create two-dimensional cross-sectional images of your body, which are then displayed on a monitor. CT ...

  11. CT of pleural abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Webb, W R [California Univ., San Francisco, CA (United States). Dept. of Radiology

    1996-12-31

    Briefly discussed were CT diagnosis of pleural thickening, CT technique for examining the pleura or pleuro-pulmonary disease, diagnosis of pleural collections, diagnosis of pleural fluid abnormalities in patients with pneumonia, pleural neoplasms, malignant (diffuse) mesothelioma, metastases, local fibrous tumor of the pleura (benign mesothelioma) (21 refs.).

  12. Tuberculous peritonitis: CT appearance

    International Nuclear Information System (INIS)

    Hanson, R.D.; Hunter, T.B.

    1985-01-01

    Rare, sporadic cases of tuberculous peritonitis do occur in the United States and other advanced countries. Because there are few descriptions of the CT appearance of the peritoneal forms of tuberculous (TB), this report illustrates a case of tuberculous peritonitis with prominent CT findings and discusses the differentiation of this entity from other, more common diseases

  13. CT urography and hematuria

    DEFF Research Database (Denmark)

    Bretlau, Thomas; Hansen, Rasmus H; Thomsen, Henrik S

    2015-01-01

    BACKGROUND: Computed tomography (CT) urography is now used in the work-up of patients with hematuria. The dose of contrast medium and radiation varies considerably between the different CT protocols. PURPOSE: To study the disease prevalence in a consecutive group of patients with hematuria...

  14. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... can help plan the safest and most effective surgery. CT of the sinuses is now widely available and is performed in a relatively short time, especially when compared to magnetic resonance imaging (MRI). CT scanning is painless, noninvasive and ...

  15. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... about tumors of the nasal cavity and sinuses. plan for surgery by defining anatomy. top of page How should ... for sinusitis. CT of the sinuses can help plan the safest and most effective surgery. CT of the sinuses is now widely available ...

  16. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) is ... a CT scan. View full size with caption Pediatric Content Some imaging tests and treatments have special ...

  17. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... or nurse at the time of the CT examination. If your child has a known contrast material ... be given to your child for the CT examination. top of page What does the CT equipment ...

  18. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... view of the body's interior. Refinements in detector technology allow new CT scanners to obtain multiple slices in a single rotation. These scanners, called "multislice CT" or "multidetector CT," ...

  19. CT of abdominal abscesses

    International Nuclear Information System (INIS)

    Korobkin, M.T.

    1987-01-01

    The imaging search for a suspected abdominal abscess is common in hospitalized patients, especially after recent abdominal surgery. This paper examines the role of CT in the detection, localization, and treatment of abdominal abscess. The accuracy, limitations, and technical aspects of CT in this clinical setting are discussed. The diagnosis of an abscess is based on the demonstration of a circumscribed abnormal fluid collection. Although percutaneous aspiration with gram stain and culture is usually indicated to differentiate abscess from other fluid collections, the CT-based detection of extraluminal gas bubbles makes the diagnosis of an abscess highly likely. CT is compared with conventional radiographic studies, US, and radio-nuclide imaging. Specific CT and clinical features of abscesses in the following sites are emphasized: subphrenic space, liver, pancreas, kidneys, psoas muscle, appendix, and colonic diverticula. Most abdominal abscesses can be successfully treated with percutaneous drainage techniques. The techniques, results, and limitations of percutaneous abscess drainage are reviewed

  20. CT of tracheal agenesis

    International Nuclear Information System (INIS)

    Strouse, Peter J.; Hernandez, Ramiro J.; Newman, Beverley

    2006-01-01

    Tracheal agenesis is a rare and usually lethal anomaly. In the past, opaque contrast medium was injected via the esophagus to demonstrate the anatomy. To demonstrate the utility of helical and multidetector CT in delineating the aberrant anatomy in newborns with tracheal agenesis. Four newborns with tracheal agenesis were identified from three institutions. Imaging studies and medical records were reviewed. Each child was imaged with chest radiography. One child was imaged on a single-detector helical CT scanner and the other three on multidetector scanners. Helical and multidetector CT with 2D and 3D reconstructions clearly delineated the aberrant tracheobronchial and esophageal anatomy in each infant. Minimum intensity projection reformatted CT images were particularly helpful. One infant each had type I and type II tracheal agenesis. Two infants had type III tracheal agenesis. All four infants died. CT is a useful tool for delineating the aberrant anatomy of newborns with tracheal agenesis and thus helps in making rational clinical decisions. (orig.)

  1. Head trauma and CT

    International Nuclear Information System (INIS)

    Samejima, Kanji; Yoshii, Nobuo; Tobari, Chitoshi

    1979-01-01

    In our cases of acute and subacute subdural hematoma, the use of CT was evaluated. In our department of surgery, acute subdural hematoma was found in 46 of 388 patients of head trauma who underwent CT. Acute subdural hematoma, like epidural hematoma was usually visualized as a high-density area along the cranial inner table, and this was easily differenciated from epidural hematoma because of difference in shape from the other. The picture of acute subdural hematoma was occasionally confused with that of intracerebral hematoma or cerebral contusion. Single use of CT does not differenciate subacute subdural hematoma from chronic subdural hematoma. However, CT usually visualized acute hematoma as a high-density area, showing the extent of hematoma. Comparison of the thickness of hematoma with the axis deviation of the median part such as the 3rd cerebral ventricle suggested severity of cerebral edema. CT also revealed bilateral or multiple lesions of cerebral contusion or intracerebral hematoma. (Ueda, J.)

  2. CT of laryngeal trauma

    International Nuclear Information System (INIS)

    Jeffrey, R.B.

    1986-01-01

    Computed tomography has made a significant contribution to the radiologic assessment of the injured larynx. CT is an accurate, noninvasive modality that can rapidly diagnose both soft tissue and cartilaginous injuries. CT of the larynx involves a minimal degree of patient manipulation and discomfort and can be performed in conjunction with CT evaluation of intracranial or facial injuries. Conventional radiologic studies (anteroposterior and lateral soft tissue films of the neck, tomograms, or xerograms) are capable of demonstrating some cartilaginous fractures but are of limited value in defining the extent of soft tissue injury. In the acute trauma setting, laryngography is often technically difficult to perform because of patient discomfort and inability to cooperate. Although the overall experience is somewhat limited, CT appears to overcome many of the limitations of these conventional radiologic methods. The following is a discussion of the role of CT scanning in evaluating injuries to the larynx and cervical soft tissues

  3. 111In-Pentetreotide SPECT/CT in Pulmonary Carcinoid.

    Science.gov (United States)

    Chiaravalloti, Agostino; Spanu, Angela; Danieli, Roberta; Dore, Francesca; Piras, Bastiana; Falchi, Antonio; Tavolozza, Mario; Madeddu, Giuseppe; Schillaci, Orazio

    2015-07-01

    We evaluated somatostatin receptor scintigraphy (SRS) with (111)In-pentetreotide incremental value in pulmonary carcinoid (PC) diagnosis compared to contrast enhanced Computed Tomography (ceCT). We enrolled 81 patients with ascertained PC, 39 at initial staging and 42 in follow-up; the primary tumor had already been excised in 68 cases. Single Photon emission Computed Tomography (SPECT) images were reconstructed with the iterative method and fused with non-enhanced Computed tomography (CT) images. Primary PC or metastatic lesions were ascertained in 55/81 patients and SPECT/CT was positive in 50/55 cases, while ceCT was positive in 44/55. Comparing SPECT/CT with ceCT results, we found a sensitivity of 96 vs. 87.5%, and specificity of 92% vs. 97% for the detection of primary lesion or recurrent disease. A total of 198 lesions were ascertained at SPECT/CT, while 161 at ceCT, with values of sensitivity and specificity of 85.5% and 84.6% for SRS and 75.2% and 90.5% respectively. (111)In-Pentetreotide SPECT/CT proved to be more sensitive and accurate than ceCT, thus enhancing its role in evaluating patients with PC. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  4. Visible light broadband perfect absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Jia, X. L.; Meng, Q. X.; Yuan, C. X.; Zhou, Z. X.; Wang, X. O., E-mail: wxo@hit.edu.cn [School of Science, Harbin Institute of Technology, Harbin 150001 (China)

    2016-03-15

    The visible light broadband perfect absorbers based on the silver (Ag) nano elliptical disks and holes array are studied using finite difference time domain simulations. The semiconducting indium silicon dioxide thin film is introduced as the space layer in this sandwiched structure. Utilizing the asymmetrical geometry of the structures, polarization sensitivity for transverse electric wave (TE)/transverse magnetic wave (TM) and left circular polarization wave (LCP)/right circular polarization wave (RCP) of the broadband absorption are gained. The absorbers with Ag nano disks and holes array show several peaks absorbance of 100% by numerical simulation. These simple and flexible perfect absorbers are particularly desirable for various potential applications including the solar energy absorber.

  5. Finding Soul: Voice and Visibility for Youth | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2010-10-22

    Oct 22, 2010 ... ... trade unions, social movements, non-governmental organizations, churches, ... Here's one way the participants proposed to develop these ideas. ... These are the kind of concerns the young people express in their music. ... ​Children are more at risk than adults for untreated or undertreated pain from ...

  6. Visible nulling coronagraph testbed results

    Science.gov (United States)

    Lyon, Richard G.; Clampin, Mark; Woodruff, Robert A.; Vasudevan, Gopal; Thompson, Patrick; Petrone, Peter; Madison, Timothy; Rizzo, Maxime; Melnick, Gary; Tolls, Volker

    2009-08-01

    We report on our recent laboratory results with the NASA/Goddard Space Flight Center (GSFC) Visible Nulling Coronagraph (VNC) testbed. We have experimentally achieved focal plane contrasts of 1 x 108 and approaching 109 at inner working angles of 2 * wavelength/D and 4 * wavelength/D respectively where D is the aperture diameter. The result was obtained using a broadband source with a narrowband spectral filter of width 10 nm centered on 630 nm. To date this is the deepest nulling result with a visible nulling coronagraph yet obtained. Developed also is a Null Control Breadboard (NCB) to assess and quantify MEMS based segmented deformable mirror technology and develop and assess closed-loop null sensing and control algorithm performance from both the pupil and focal planes. We have demonstrated closed-loop control at 27 Hz in the laboratory environment. Efforts are underway to first bring the contrast to > 109 necessary for the direct detection and characterization of jovian (Jupiter-like) and then to > 1010 necessary for terrestrial (Earth-like) exosolar planets. Short term advancements are expected to both broaden the spectral passband from 10 nm to 100 nm and to increase both the long-term stability to > 2 hours and the extent of the null out to a ~ 10 * wavelength / D via the use of MEMS based segmented deformable mirror technology, a coherent fiber bundle, achromatic phase shifters, all in a vacuum chamber at the GSFC VNC facility. Additionally an extreme stability textbook sized compact VNC is under development.

  7. Intracranial CT angiography obtained from a cerebral CT perfusion examination

    International Nuclear Information System (INIS)

    Gratama van Andel, H. A. F.; Venema, H. W.; Majoie, C. B.; Den Heeten, G. J.; Grimbergen, C. A.; Streekstra, G. J.

    2009-01-01

    CT perfusion (CTP) examinations of the brain are performed increasingly for the evaluation of cerebral blood flow in patients with stroke and vasospasm after subarachnoid hemorrhage. Of the same patient often also a CT angiography (CTA) examination is performed. This study investigates the possibility to obtain CTA images from the CTP examination, thereby possibly obviating the CTA examination. This would save the patient exposure to radiation, contrast, and time. Each CTP frame is a CTA image with a varying amount of contrast enhancement and with high noise. To improve the contrast-to-noise ratio (CNR) we combined all 3D images into one 3D image after registration to correct for patient motion between time frames. Image combination consists of weighted averaging in which the weighting factor of each frame is proportional to the arterial contrast. It can be shown that the arterial CNR is maximized in this procedure. An additional advantage of the use of the time series of CTP images is that automatic differentiation between arteries and veins is possible. This feature was used to mask veins in the resulting 3D images to enhance visibility of arteries in maximum intensity projection (MIP) images. With a Philips Brilliance 64 CT scanner (64x0.625 mm) CTP examinations of eight patients were performed on 80 mm of brain using the toggling table technique. The CTP examination consisted of a time series of 15 3D images (2x64x0.625 mm; 80 kV; 150 mAs each) with an interval of 4 s. The authors measured the CNR in images obtained with weighted averaging, images obtained with plain averaging, and images with maximal arterial enhancement. The authors also compared CNR and quality of the images with that of regular CTA examinations and examined the effectiveness of automatic vein masking in MIP images. The CNR of the weighted averaged images is, on the average, 1.73 times the CNR of an image at maximal arterial enhancement in the CTP series, where the use of plain averaging

  8. The CT appearance of intraoral chewing gum

    International Nuclear Information System (INIS)

    Towbin, Alexander J.

    2008-01-01

    When imaged, intraoral chewing gum has the potential to be misdiagnosed. Chewing gum has a characteristic appearance on CT: it is ovoid in shape, hyperdense, and has small internal locules of air. Reports have described the appearance of gum on radiographs and abdominal CT images; however, no reports could be found detailing its appearance within the mouth. This report describes the appearance of intraoral chewing gum as well as the properties of the gum that lead to this appearance. Because of the potential for misdiagnosis, screening for intraoral foreign bodies should be considered prior to imaging. (orig.)

  9. Rapid reformatting of cine CT data

    International Nuclear Information System (INIS)

    Wyatt, E.D.; Reynolds, R.A.

    1989-01-01

    Cine CT scanners acquire data sufficiently rapidly to freeze the cardiac motion. Display hardware with sufficient highspeed computer memory permits instantaneous reformatting of sections at any orientation. Normal or abnormal cardiac motion may be studies interactively along any axial, sagittal, coronal, or oblique plane through the beating heart. Cine Ct studies, consisting of eight levels through the heart with 8-mm interlevel spacing, acquired at 10 time intervals for a total of 80 sections, were acquired on an Imatron C-100 scanner and displayed. Each entire study was loaded into t = internal display processor memory, permitting instantaneous recall without loss of spatial or density resolution. Results are presented

  10. The CT appearance of intraoral chewing gum

    Energy Technology Data Exchange (ETDEWEB)

    Towbin, Alexander J. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States)

    2008-12-15

    When imaged, intraoral chewing gum has the potential to be misdiagnosed. Chewing gum has a characteristic appearance on CT: it is ovoid in shape, hyperdense, and has small internal locules of air. Reports have described the appearance of gum on radiographs and abdominal CT images; however, no reports could be found detailing its appearance within the mouth. This report describes the appearance of intraoral chewing gum as well as the properties of the gum that lead to this appearance. Because of the potential for misdiagnosis, screening for intraoral foreign bodies should be considered prior to imaging. (orig.)

  11. CT after transsphenoidal surgery

    International Nuclear Information System (INIS)

    Tazawa, Satoru

    1991-01-01

    Two hundred and ten CT studies of 95 patients after transsphenoidal surgery were reviewed. Spheno-ethmoid opacificaiton, intrasellar hematoma and gas bubbles were noted within 2 weeks after surgery. Bone defect of the sellar floor and bone stent were seen on coronal scans in most cases. The packing material frequently disappeared on follow-up studies. Hormonal assessment of the functioning tumor, according to which the effect of treatment was evaluated, was correlated with CT findings. Because differentiation between postoperative changes and residual mass was difficult, there was no definite CT criteria to indicate residual functioning tumor except upward convexity of the diaphragma sellae on CT more than 3 months after surgery. Initial follow up CT study is recommended to be performed at about 3 months after surgery, at which time the immediate postoperative inflammatory changes have been disappeared. The incidence of recurrence was 3/47 (6%), which was shown on follow-up CT from 4 to 10 years after surgery. Therefore, subsequent CT study should be done in every year or two, taking the clinical symptoms and hormonal data into consideration. (author)

  12. CT of the heart

    International Nuclear Information System (INIS)

    Lipton, M.J.

    1986-01-01

    Advances based upon the detector elements instead of X-ray film have greatly increased the power of X-ray imaging. Computed tomography (CT) creates cross sectional rather than projected images. Recently, high speed CT devices have been developed for cardiovascular studies. The Cine-CT scanner employs a scanning electron beam deflected on an extended tungsten target ring. Fast scans of 50 millisecond exposures at multiple levels can provide information concerning blood flow in vessels and tissues, myocardial wall motion, valve integrity, coronary bypass graft patency and proximal coronary artery anatomy. Cine-CT dynamic scanning can also provide volume imaging with small quantities (0.05 - 1.5 ml/kg) of contrast medium administered via peripheral vein injections. Cine-CT provides simultaneous measurements of cardiac dimensions and function and is rapidly becoming a new tool for quantitating myocardial blood flow, cardiac chamber volumes and wall mechanics. The future outlook is very promising for this three-dimensional cine-CT technique with high spatial resolution. High speed CT should provide unique diagnostic information and as the technology continues to improve at a rapid speed, this new imaging modality could be a challenge for angiography. (Auth.)

  13. CT after transsphenoidal surgery

    Energy Technology Data Exchange (ETDEWEB)

    Tazawa, Satoru [Tohoku Univ., Sendai (Japan). School of Medicine

    1991-03-01

    Two hundred and ten CT studies of 95 patients after transsphenoidal surgery were reviewed. Spheno-ethmoid opacificaiton, intrasellar hematoma and gas bubbles were noted within 2 weeks after surgery. Bone defect of the sellar floor and bone stent were seen on coronal scans in most cases. The packing material frequently disappeared on follow-up studies. Hormonal assessment of the functioning tumor, according to which the effect of treatment was evaluated, was correlated with CT findings. Because differentiation between postoperative changes and residual mass was difficult, there was no definite CT criteria to indicate residual functioning tumor except upward convexity of the diaphragma sellae on CT more than 3 months after surgery. Initial follow up CT study is recommended to be performed at about 3 months after surgery, at which time the immediate postoperative inflammatory changes have been disappeared. The incidence of recurrence was 3/47 (6%), which was shown on follow-up CT from 4 to 10 years after surgery. Therefore, subsequent CT study should be done in every year or two, taking the clinical symptoms and hormonal data into consideration. (author).

  14. Correlative Imaging in a Patient with Cystic Thymoma: CT, MR and PET/CT Comparison

    International Nuclear Information System (INIS)

    Romeo, Valeria; Esposito, Alfredo; Maurea, Simone; Camera, Luigi; Mainenti, Pier Paolo; Palmieri, Giovannella; Buonerba, Carlo; Salvatore, Marco

    2015-01-01

    Cystic thymoma is a rare variant of thymic neoplasm characterized by almost complete cystic degeneration with mixed internal structure. We describe a case of a 60 year-old woman with a cystic thymoma studied with advanced tomographic imaging stydies. CT, MRI and PET/CT with 18 F-FDG were performed; volumetric CT and MRI images provided better anatomic evaluation for pre-operative assessment, while PET/CT was helpful for lesion characterization based on 18 F-FDG uptake. Although imaging studies are mandatory for pre-operative evaluation of cystic thymoma, final diagnosis still remains surgical. A 60-year-old woman with recent chest pain and no history of previous disease was admitted to our departement to investigate the result of a previous chest X-ray that showed bilateral mediastinal enlargement; for this purpose, enhanced chest CT scan was performed using a 64-rows scanner (Toshiba, Aquilion 64, Japan) before and after intravenous bolus administration of iodinated non ionic contrast agent; CT images demonstrated the presence of a large mediastinal mass (11×8 cm) located in the anterior mediastinum who extended from the anonymous vein to the cardio-phrenic space, compressing the left atrium and causing medium lobe atelectasis; bilateral pleural effusion was also present. In conclusion, correlative imaging plays a foundamental role for the diagnostic evaluation of patient with cystic thymoma. In particular, volumetric CT and MRI studies can provide better anatomic informations regarding internal structure and local tumor spread for pre-operative assessment. Conversely, metabolic imaging using 18 F-FDG PET/CT is helpful for lesion characterization differentiating benign from malignant lesion on the basis of intense tracer uptake. The role of PET/MRI is still under investigation. However, final diagnosis still remains surgical even though imaging studies are mandatory for pre-operative patient management

  15. A New Coding System for Metabolic Disorders Demonstrates Gaps in the International Disease Classifications ICD-10 and SNOMED-CT, Which Can Be Barriers to Genotype-Phenotype Data Sharing

    NARCIS (Netherlands)

    Sollie, Annet; Sijmons, Rolf H.; Lindhout, Dick; van der Ploeg, Ans T.; Gozalbo, M. Estela Rubio; Smit, G. Peter A.; Verheijen, Frans; Waterham, Hans R.; van Weely, Sonja; Wijburg, Frits A.; Wijburg, Rudolph; Visser, Gepke

    Data sharing is essential for a better understanding of genetic disorders. Good phenotype coding plays a key role in this process. Unfortunately, the two most widely used coding systems in medicine, ICD-10 and SNOMED-CT, lack information necessary for the detailed classification and annotation of

  16. CT pelvimetry. La scanopelvimetrie

    Energy Technology Data Exchange (ETDEWEB)

    Vicens, J.L.; Charles, G.; Le Berre, J.; Flageat, J. (Hopital d' Instruction des Armees Begin, 94 - Saint-Mande (FR))

    1989-01-01

    Pelvimetry aims at providing the obstetrician with information on the size and morphology of the female pelvis, thus enabling him to assess the obstetrical prognosis as accurately as possible. Computed tomography (CT) has several advantages, in particular the lower mother and fetus radiation dose. After a brief description of obstetrical anatomy, the usual CT exploration method is presented and its results are considered in terms of measurements, indices and morphological findings. If performed with a very strict exploration procedure, CT pelvimetry is a very reliable, fact and comfortable method of examination. All these advantages, combined with the minimized patient dose, should lead to an increasingly widespread use of this technique.

  17. CT of chest trauma

    International Nuclear Information System (INIS)

    Goodman, P.C.

    1986-01-01

    There appears to be a limited role for computed tomography in the evaluation of chest trauma. The literature contains few papers specifically addressing the use of CT in the setting of chest trauma. Another series of articles relates anecdotal experiences in this regard. This paucity of reports attests to the remarkable amount of information present on conventional chest radiographs as well as the lack of clear indications for CT in the setting of chest trauma. In this chapter traumatic lesions of various areas of the thorax are discussed. The conventional radiographic findings are briefly described and the potential or proven application of CT is addressed

  18. NMR-CT scanner

    International Nuclear Information System (INIS)

    Kose, Katsumi; Sato, Kozo; Sugimoto, Hiroshi; Sato, Masataka.

    1983-01-01

    A brief explanation is made on the imaging methods for a practical diagnostic NMR-CT scanner : A whole-body NMR-CT scanner utilizing a resistive magnet has been developed by Toshiba in cooperation with the Institute for Solid State Physics, the University of Tokyo. Typical NMR-CT images of volunteers and patients obtained in the clinical experiments using this device are presented. Detailed specifications are also shown about the practical NMR-CTs which are to be put on the market after obtaining the government approval. (author)

  19. Dual energy cardiac CT.

    Science.gov (United States)

    Carrascosa, Patricia; Deviggiano, Alejandro; Rodriguez-Granillo, Gastón

    2017-06-01

    Conventional single energy CT suffers from technical limitations related to the polychromatic nature of X-rays. Dual energy cardiac CT (DECT) shows promise to attenuate and even overcome some of these limitations, and might broaden the scope of patients eligible for cardiac CT towards the inclusion of higher risk patients. This might be achieved as a result of both safety (contrast reduction) and physiopathological (myocardial perfusion and characterization) issues. In this article, we will review the main clinical cardiac applications of DECT, that can be summarized in two core aspects: coronary artery evaluation, and myocardial evaluation.

  20. CT of the temporomandibular joint: The conservative approach

    International Nuclear Information System (INIS)

    Jend, H.H.; Jend-Rossmann, I.; Heller, M.

    1986-01-01

    Until recently, CT investigation of temporomandibular joint (TMJ) disorders has been regarded as a sophisticated procedure. A method of investigation was developed that allows easy evaluation of axial scans. The method was evaluated in a series of 65 joints with arthrographically diagnosed internal derangements. In anterior disk displacement CT findings led to an identical diagnosis in 56 of 65 joints (sensitivity, 86%). In clinically asymptomatic joints investigated for other reasons, only one of 12 showed signs of internal derangement on CT (specificity, 92%). This conservative approach to CT evaluation of internal derangement seems to be as accurate as more sophisticated methods. It is easy to perform, requires no additional manpower or computer time, and has a very good reproducibility

  1. Energy Awareness Displays - Making the Invisible Visible

    NARCIS (Netherlands)

    Börner, Dirk

    2011-01-01

    Börner, D. (2011). Energy Awareness Displays - Making the Invisible Visible. Presentation given at the Startbijeenkomst SURFnet Innovatieregeling Duurzaamheid & ICT. May, 13, 2011, Utrecht, The Netherlands.

  2. 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

  3. Neck after total laryngectomy: CT study

    International Nuclear Information System (INIS)

    DiSantis, D.J.; Balfe, D.M.; Hayden, R.E.; Sagel, S.S.; Sessions, D.; Lee, J.K.T.

    1984-01-01

    Computed tomographic scans in 23 patients who had undergone total laryngectomy were analyzed retrospectively to determine normal postoperative appearance and to evaluate the role of CT in assessing recurrent neoplasm. Nine patients without clinical evidence of recurrence illustrated the normal postoperative changes: a round or ovoid neopharynx connecting the base of the tongue with the cervical esophagus and intact fat planes surrounding the neopharynx, neurovascular bundles, and sternocleidomastoid muscles. In the 12 patients with recurrent neoplasm, the CT manifestations included masses involving the internal jugular lymph node chain, tracheostomy site, or paratracheal region. CT supplemented physical examination and indirect mirror examination, providing data regarding presence and extent of recurrent tumor and aiding in planning the mode and scope of therapy

  4. CT findings of superior vena cava syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jun; Lee, Jae Mun; Kim, Choon Yul; Bahk, Yong Whee [Catholic Medical College, Seoul (Korea, Republic of)

    1986-10-15

    Since early 1980's high resolution CT has been used for detection of intrathoracic pathologic condition such as superior vena cava syndrome. Authors retrospectively analysed CT findings of 18 cases of proven SVC syndrome. The results were as follows: 1. The mean age was 50-year-old, and 14 cases were male. 2. Of 18 cases of SVC syndrome, 8 cases had confirmed to be lung cancers, malignant thymoma and teratoma were respectively each 2 cases, and malignant lymphoma, mediastinal abscess, thyroid adenoma and metastatic tumor were 1 case. 3. CT findings were A. Abnormal SVC consisted of compression with displacement (44.4%), intraluminal thrombus (27.8%), and encasement (27.8%). B. The collateral pathways were the azygos-homozygous (88.8%), vertebral (50%), internal mammary (44.4%), and lateral thoracic route (33.3%)

  5. CT findings of superior vena cava syndrome

    International Nuclear Information System (INIS)

    Lim, Jun; Lee, Jae Mun; Kim, Choon Yul; Bahk, Yong Whee

    1986-01-01

    Since early 1980's high resolution CT has been used for detection of intrathoracic pathologic condition such as superior vena cava syndrome. Authors retrospectively analysed CT findings of 18 cases of proven SVC syndrome. The results were as follows: 1. The mean age was 50-year-old, and 14 cases were male. 2. Of 18 cases of SVC syndrome, 8 cases had confirmed to be lung cancers, malignant thymoma and teratoma were respectively each 2 cases, and malignant lymphoma, mediastinal abscess, thyroid adenoma and metastatic tumor were 1 case. 3. CT findings were A. Abnormal SVC consisted of compression with displacement (44.4%), intraluminal thrombus (27.8%), and encasement (27.8%). B. The collateral pathways were the azygos-homozygous (88.8%), vertebral (50%), internal mammary (44.4%), and lateral thoracic route (33.3%).

  6. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... still during the exam. Some patients require an injection of a contrast material to enhance the visibility ... likely have a warm, flushed sensation during the injection of the contrast materials and a metallic taste ...

  7. Visibility of wavelet quantization noise

    Science.gov (United States)

    Watson, A. B.; Yang, G. Y.; Solomon, J. A.; Villasenor, J.

    1997-01-01

    The discrete wavelet transform (DWT) decomposes an image into bands that vary in spatial frequency and orientation. It is widely used for image compression. Measures of the visibility of DWT quantization errors are required to achieve optimal compression. Uniform quantization of a single band of coefficients results in an artifact that we call DWT uniform quantization noise; it is the sum of a lattice of random amplitude basis functions of the corresponding DWT synthesis filter. We measured visual detection thresholds for samples of DWT uniform quantization noise in Y, Cb, and Cr color channels. The spatial frequency of a wavelet is r 2-lambda, where r is display visual resolution in pixels/degree, and lambda is the wavelet level. Thresholds increase rapidly with wavelet spatial frequency. Thresholds also increase from Y to Cr to Cb, and with orientation from lowpass to horizontal/vertical to diagonal. We construct a mathematical model for DWT noise detection thresholds that is a function of level, orientation, and display visual resolution. This allows calculation of a "perceptually lossless" quantization matrix for which all errors are in theory below the visual threshold. The model may also be used as the basis for adaptive quantization schemes.

  8. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... of any kind, unlike MRI. CT imaging provides real-time imaging, making it a good tool for guiding ... information is needed to determine the extent of soft tissue of the tumor, magnetic resonance imaging (MRI) ...

  9. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... is reduced. Though the scanning itself causes no pain, there may be some discomfort from having to ... time staying still, are claustrophobic, or have chronic pain, you may find a CT exam to be ...

  10. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... is reduced. Though the scanning itself causes no pain, there may be some discomfort from having to ... time staying still, are claustrophobic or have chronic pain, you may find a CT exam to be ...

  11. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... wear during the procedure. Metal objects, including jewelry, eyeglasses, dentures and hairpins, may affect the CT images ... and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media ...

  12. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... wear during the procedure. Metal objects, including jewelry, eyeglasses, dentures and hairpins, may affect the CT images ... and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media ...

  13. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... wear during the procedure. Metal objects, including jewelry, eyeglasses, dentures and hairpins, may affect the CT images ... and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media ...

  14. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... that lasts for at most a minute or two. You may experience a sensation like you have ... CT scanning provides very detailed images of many types of tissue as well as the lungs, bones, ...

  15. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... that lasts for at most a minute or two. You may experience a sensation like you have ... CT scanning provides very detailed images of many types of tissue as well as the lungs, bones, ...

  16. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... have a history of heart disease, asthma, diabetes, kidney disease or thyroid problems. Any of these conditions may ... hard time staying still, are claustrophobic, or have chronic pain, you may find a CT exam to ...

  17. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... have a history of heart disease, asthma, diabetes, kidney disease or thyroid problems. Any of these conditions may ... hard time staying still, are claustrophobic or have chronic pain, you may find a CT exam to ...

  18. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... have a history of heart disease, asthma, diabetes, kidney disease or thyroid problems. Any of these conditions may ... still, are very nervous or anxious or have chronic pain, you may find a CT exam to ...

  19. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... detailed images of many types of tissue as well as the lungs, bones, and blood vessels. CT ... iodine is extremely rare, and radiology departments are well-equipped to deal with them. Because children are ...

  20. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... detailed images of many types of tissue as well as the lungs, bones, and blood vessels. CT ... iodine is extremely rare, and radiology departments are well-equipped to deal with them. Because children are ...

  1. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... CT of the sinuses is primarily used to: help diagnose sinusitis . evaluate sinuses that are filled with ... elevated. Straps and pillows may be used to help the patient maintain the correct position and to ...

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    Energy Technology Data Exchange (ETDEWEB)

    Itai, Yuji [Tokyo Univ. (Japan). Faculty of Medicine

    1982-04-01

    In hepatocellular carcinoma, present status of CT diagnosis was discussed. Hepatocellular carcinoma is sometimes imaged in same concentration as that of surrounding tissues, and the detection rate ranged from 79 to 94%. The rate of differential diagnosis between primary and metastatic carcinoma was only 83% (includes 22% of false diagnosis) using contrast enhancement. The rates of detection of hepatocellular carcinoma and metastatic one were also only 87% and 75%, respectively, even by the combined use of arterial infusion CT and dynamic CT. However, the CT images is reproducible, and is supplemented by the information of US. Thus, the combination of these methods is useful in diagnosing the presence, extension, and nature of liver carcinoma.

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    The Radiation Epidemiology Branch and collaborators have initiated a retrospective cohort study to evaluate the relationship between radiation exposure from CT scans conducted during childhood and adolescence and the subsequent development of cancer.

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    Science.gov (United States)

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  17. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... the CT images and should be left at home or removed prior to your exam. You may also be asked to remove hearing aids and removable dental work. Women will be asked to remove bras containing ...

  18. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... the CT images and should be left at home or removed prior to your exam. You may also be asked to remove hearing aids and removable dental work. Women will be asked to remove bras containing ...

  19. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... the CT images and should be left at home or removed prior to your exam. You may also be asked to remove hearing aids and removable dental work. Women will be asked to remove bras containing ...

  20. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... blood vessels. If contrast material is required, a nurse or technologist will insert an intravenous (IV) line ... CT exam to be stressful. The technologist or nurse, under the direction of a physician, may offer ...