• Journal of Veterinary Science
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• v.24 no.5
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• pp.65.1-65.9
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• 2023

Background: Bone subtraction computed tomography angiography (BSCTA) is a useful alternative technique for improving visualization of vessels surrounded by skull bone. However, no studies have compared computed tomography angiography (CTA) and BSCTA for improving the visibility of canine cerebral blood vessels. Objectives: To evaluate the potential benefit of BSCTA for better delineation of brain arteries of the circle of Willis (CoW) in dogs by comparing BSCTA with non-subtraction computed tomography angiography (NSCTA). Methods: Brain CTA was performed for nine healthy beagle dogs using a bolus tracking method with saline flushing. A total dose of 600 mgI/kg of contrast agent with an iodine content of 370 mgI/mL was injected at a rate of 4 ml/s. Bone removal was achieved automatically by subtracting non-enhanced computed tomography (CT) data from contrast CT data. Five main intracranial arteries of the CoW were analyzed and graded on a scale of five for qualitative evaluation. Results: Scores of basilar artery, middle cerebral artery, and rostral cerebral artery in the BSCTA group were significantly higher than those in the NSCTA group (p = 0.001, p = 0.020, and p < 0.0001, respectively). Scores of rostral cerebellar artery (RcA) and caudal cerebral artery (CCA) did not differ significantly between the two groups. However, scores of RcA and CCA in the BSCTA group were higher than those in the NSCTA group. Conclusions: BSCTA improved visualization of intracranial arteries of the CoW with close contact to bone. Thus, it should be recommended as a routine scan method in dogs suspected of having brain vessel disease.

• Journal of Biomedical Engineering Research
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• v.30 no.5
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• pp.412-417
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• 2009

The purpose of this study was to assess the ability of this device during clinically important episodes of extravasation. The extravasation detection accessory (EDA) system was based of infrared ray with detection sensor, an amplifier, alarm device, receiver, cable and a computer based system. This study was a prospective, observational study in which the EDA system was used to monitor the automated mechanical injection of contrast media. Three hundred patients referred for contrast media enhanced body computed tomography studied in a prospective, observation study in which the EDA system was used to identify and interrupt any injection associated with clinically important extravasation. There were 8 true-positive cases, 276 true-negative cases, 15 false-positive cases and 1 false-negative cases. The EDA system had a sensitivity of 88.8% and a specificity of 94.8% for the detection of clinically important extravasation. The EDA system had good sensitivity for the detection of clinically important extravasation and the EDA system has the clinical potential for the early detection of extravasation of the contrast medium that is administered with power injectors.

• Korean Journal of Radiology
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• v.24 no.10
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• pp.983-995
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• 2023

Objective: To compare the diagnostic performance and interobserver agreement between contrast-enhanced computed tomography (CECT) and contrast-enhanced magnetic resonance imaging (CE-MRI) with magnetic resonance cholangiopancreatography (MRCP) for evaluating the resectability in patients with extrahepatic cholangiocarcinoma (eCCA). Materials and Methods: This retrospective study included treatment-naïve patients with pathologically confirmed eCCA, who underwent both CECT and CE-MRI with MRCP using extracellular contrast media between January 2015 and December 2020. Among the 214 patients (146 males; mean age ± standard deviation, 68 ± 9 years) included, 121 (56.5%) had perihilar cholangiocarcinoma. R0 resection was achieved in 108 of the 153 (70.6%) patients who underwent curative-intent surgery. Four fellowship-trained radiologists independently reviewed the findings of both CECT and CE-MRI with MRCP to assess the local tumor extent and distant metastasis for determining resectability. The pooled area under the receiver operating characteristic curve (AUC), sensitivity, and specificity of CECT and CE-MRI with MRCP were compared using clinical, surgical, and pathological findings as reference standards. The interobserver agreement of resectability was evaluated using Fleiss kappa (κ). Results: No significant differences were observed between CECT and CE-MRI with MRCP in the pooled AUC (0.753 vs. 0.767), sensitivity (84.7% [366/432] vs. 90.3% [390/432]), and specificity (52.6% [223/424] vs. 51.4% [218/424]) (P > 0.05 for all). The AUC for determining resectability was higher when CECT and CE-MRI with MRCP were reviewed together than when CECT was reviewed alone in patients with discrepancies between the imaging modalities or with indeterminate resectability (0.798 [0.754-0.841] vs. 0.753 [0.697-0.808], P = 0.014). The interobserver agreement for overall resectability was fair for both CECT (κ = 0.323) and CE-MRI with MRCP (κ = 0.320), without a significant difference (P = 0.884). Conclusion: CECT and CE-MRI with MRCP showed no significant differences in the diagnostic performance and interobserver agreement in determining the resectability in patients with eCCA.

• Imaging Science in Dentistry
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• v.45 no.1
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• pp.31-39
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• 2015

Purpose: This study was performed to evaluate the feasibility of visualizing soft tissue lesions and vascular structures using contrast-enhanced cone-beam computed tomography (CE-CBCT) after the intravenous administration of a contrast medium in an animal model. Materials and Methods: CBCT was performed on six rabbits after a contrast medium was administered using an injection dose of 2 mL/kg body weight and an injection rate of 1 mL/s via the ear vein or femoral vein under general anesthesia. Artificial soft tissue lesions were created through the transplantation of autologous fatty tissue into the salivary gland. Volume rendering reconstruction, maximum intensity projection, and multiplanar reconstruction images were reconstructed and evaluated in order to visualize soft tissue contrast and vascular structures. Results: The contrast enhancement of soft tissue was possible using all contrast medium injection parameters. An adequate contrast medium injection parameter for facilitating effective CE-CBCT was a 5-mL injection before exposure combined with a continuous 5-mL injection during scanning. Artificial soft tissue lesions were successfully created in the animals. The CE-CBCT images demonstrated adequate opacification of the soft tissues and vascular structures. Conclusion: Despite limited soft tissue resolution, the opacification of vascular structures was observed and artificial soft tissue lesions were visualized with sufficient contrast to the surrounding structures. The vascular structures and soft tissue lesions appeared well delineated in the CE-CBCT images, which was probably due to the superior spatial resolution of CE-CBCT compared to other techniques, such as multislice computed tomography.

• Korean Journal of Radiology
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• v.19 no.6
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• pp.1089-1098
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• 2018

Objective: To investigate the diagnostic yield of contrast-enhanced computed tomography (CT) in Crohn's disease (CD) patients presenting with acute severe lower gastrointestinal bleeding (LGIB), and the role of CT in predicting the risk of rebleeding. Materials and Methods: A consecutive series of 110 CD patients presenting with acute severe LGIB between 2005 and 2016 were analyzed. Among them, 86 patients who had undergone contrast-enhanced CT constituted the study cohort. The diagnostic yield of CT for detecting contrast extravasation was obtained for the entire cohort and compared between different CT techniques. In a subgroup of 62 patients who had undergone CT enterography (CTE) and showed a negative result for extravasation on CTE, the association between various clinical and CTE parameters and the risk of rebleeding during subsequent follow-up was investigated using Cox regression analysis. Results: The diagnostic yield of CT was 10.5% (9 of 86 patients). The yield did not significantly differ between single-phase and multiphase examinations (p > 0.999), or between non-enterographic CT and CTE (p = 0.388). Extensive CD (adjusted hazard ratio [HR], 3.27; 95% confidence interval [CI], 1.09-9.80; p = 0.034) and bowel wall-to-artery enhancement ratio (adjusted HR, 2.81; 95% CI, 1.21-6.54; p = 0.016) were significantly independently associated with increased rebleeding risks, whereas anti-tumor necrosis factor-${\alpha}$ therapy after the bleeding independently decreased the risk of rebleeding (adjusted HR, 0.26; 95% CI, 0.07-0.95; p = 0.041). Conclusion: The diagnostic yield of contrast-enhanced CT was not high in CD patients presenting with acute severe LGIB. Nevertheless, even a negative CTE may be beneficial as it can help predict the risk of later rebleeding.

• Investigative Magnetic Resonance Imaging
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• v.15 no.1
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• pp.41-47
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• 2011

Purpose : To evaluate the cause of internal jugular vein (IJV) obstruction on contrast enhanced 3D MR angiography (CE-MRA) using contrast enhanced computed tomography (CE-CT). Materials and Methods : A total number of 30 patients were enrolled, who underwent both head and neck CE-MRA and CE-CT from 2005 to 2008. We defined obstruction group which had IJV obstruction and control group which had no IJV obstruction on CE-MRA. The following parameters were measured from axial images of CE-CT: 1) diameter of IJV; 2) distance between the styloid process and ipsilateral lateral mass of the atlas; 3) maximum area of lateral mass of the atlas. Each parameter was compared between obstruction group and control group. Results : The diameter of IJV and distance between the styloid process and lateral mass of the atlas at IJV obstruction side in obstruction group were $1.6{\pm}1.0\;mm$ and $4.1{\pm}2.1\;mm$ respectively, which resulted in statistical significance (p<0.01). The maximum area of lateral mass of the atlas at IJV obstruction side in obstruction group was $103.4{\pm}25.3\;mm^2$ which is significantly larger than in control group (p<0.05). Conclusion : We found that the cause of IJV obstruction on CE-MRA could be narrow space between the styloid process and the lateral mass of the atlas, which was related with asymmetric larger area of lateral mass of atlas.

• Progress in Medical Physics
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• v.17 no.1
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• pp.32-39
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• 2006

To assess the ability of an extravasation detection accessory (EDA) system to detect clinically important extravascular injection of iodinated contrast material delivered with an automated power injector. Fifty patients referred for contrast material enhanced body computed tomography studied in a prospective, observation study in which the EDA system was used to identify and interrupt any injection associated with clinically Important extravasation. The presence or absence of extravasation was definitively established with multi-detector CT at the injection site (injection rate, $2.0{\sim}2.5$ mL/sec). There were two true positive, extravasation volumes $22{\sim}25$ mL. The EDA system had sensitivity in the detection of clinically important extravasation. The EDA system is easy to use, safe, and accurate In the monitoring of intravenous injections for extravasation, which may prove especially useful in CT applications.

• Korean Journal of Radiology
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• v.22 no.5
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• pp.735-741
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• 2021

Objective: To evaluate circularity as a quantitative shape factor of small renal tumor on computed tomography (CT) in differentiating fat-poor angiomyolipoma (AML) from renal cell carcinoma (RCC). Materials and Methods: In 257 consecutive patients, 257 pathologically confirmed renal tumors (either AML or RCC less than 4 cm), which did not include visible fat on unenhanced CT, were retrospectively evaluated. A radiologist drew the tumor margin to measure the perimeter and area in all the contrast-enhanced axial CT images. In each image, a quantitative shape factor, circularity, was calculated using the following equation: 4 x π x (area ÷ perimeter²). The median circularity (circularity index) was adopted as a representative value in each tumor. The circularity index was compared between fat-poor AML and RCC, and the receiver operating characteristic (ROC) curve analysis was performed. Univariable and multivariable binary logistic regression analysis was performed to determine the independent predictor of fat-poor AML. Results: Of the 257 tumors, 26 were AMLs and 231 were RCCs (184 clear cell RCCs, 25 papillary RCCs, and 22 chromophobe RCCs). The mean circularity index of AML was significantly lower than that of RCC (0.86 ± 0.04 vs. 0.93 ± 0.02, p < 0.001). The mean circularity index was not different between the subtypes of RCCs (0.93 ± 0.02, 0.92 ± 0.02, and 0.92 ± 0.02 for clear cell, papillary, and chromophobe RCCs, respectively, p = 0.210). The area under the ROC curve of circularity index was 0.924 for differentiating fat-poor AML from RCC. The sensitivity and specificity were 88.5% and 90.9%, respectively (cut-off, 0.90). Lower circularity index (≤ 0.9) was an independent predictor (odds ratio, 41.0; p < 0.001) for predicting fat-poor AML on multivariable logistic regression analysis. Conclusion: Circularity is a useful quantitative shape factor of small renal tumor for differentiating fat-poor AML from RCC.

• Journal of Trauma and Injury
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• v.19 no.2
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• pp.192-195
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• 2006

Degenerative vascular disease, previous arterial surgery, long-term ureteral stenting, pelvis surgery, and radiotheraphy are reported as causes of artery-to-collecting-system communication.. Artery-to-collecting-system- communication associated with blunt trauma is rare, but potentially fatal. The diagnosis is very difficult and requires a high degree of suspicion. We were able to make the diagnosis based on the characteristic finding of contrast-enhanced computed tomography (CT) obtained in the early phase, equivalent to the finding obtained in the corticomedullary phase of the kidney. We report a case of artery to collecting system communication due to blunt abdominal trauma following a fall, which was treated by embolization.

• Journal of Korean Neurosurgical Society
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• v.54 no.5
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• pp.434-436
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• 2013

Isolated oculomotor nerve palsy (ONP) attributable to mild closed head trauma is a distinct rarity. Its diagnosis places high demands on the radiologist and the clinician. The authors describe this condition in a 36-year-old woman who slipped while walking and struck her face. Initial computed tomography did not reveal any causative cerebral and vascular lesions or orbital and cranial fractures. Enhancement and swelling of the cisternal segment of the oculomotor nerve was seen during the subacute phase on thin-sectioned contrast-enhanced magnetic resonance images. The current case received corticosteroid therapy, and then recovered fully in 13 months after injury. Possible mechanism of ONP from minor head injury is proposed and previous reports in the literature are reviewed.