• Korean Journal of Radiology
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• v.19 no.6
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• pp.1066-1076
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• 2018

Objective: The reliability of size measurements of liver metastases from neuroendocrine tumors (NETs) on contrast-enhanced computed tomography (CT) phases made by different readers may be hampered due to transient, variable rim enhancement in arterial phase (AP) or portal venous phase (PVP) images. We aimed to assess the reliability of tumor size measurements in pre- and post-contrast scans. Materials and Methods: The study coordinator selected target lesions according to Response Evaluation Criteria in Solid Tumors 1.1 guidelines in 44 consecutive patients with pathologically confirmed NET liver metastases. Two blinded readers measured the longest diameters of target lesions on pre-contrast, AP, and PVP images twice with a 4-week interval. Inter- and intra-observer agreements were evaluated using Bland-Altman plots and 95% limit of agreement (LOA) calculations. Results: Of the 79 target lesions (approximate mean size of 3 cm), 45 showed rim enhancement. Inter-observer agreement assessed based on LOA was highest in pre-contrast CT images (-6.1-5.7 mm), followed by PVP (-7.9-7.1 mm) and AP (-8.5-7.4 mm) images. Intra-observer agreement showed the same trend: -2.8-2.9 mm and -2.9-2.9 mm for readers 1 and 2, respectively, on pre-contrast CT, -2.8-2.9 mm and -3.0-3.2 mm, respectively, on PVP, and -3.2-4.2 mm and -3.4-3.2 mm, respectively, on AP images. Mean tumor diameters differed significantly among the phases in the following increasing order: pre-contrast CT, PVP, and AP images. Conclusion: There was better inter- and intra-observer agreement in size measurements of NET liver metastases on pre-contrast scans than on AP and PVP scans. Pre-contrast CT may be the optimal for measuring NET liver metastases if its accuracy is proven.

• Korean Journal of Radiology
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• v.25 no.3
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• pp.257-266
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• 2024

Objective: To investigate molecular and functional consequences of additional exposures to iodine- or gadolinium-based contrast agents within 24 hours from the initial intravenous administration of iodine-based contrast agents through an animal study. Materials and Methods: Fifty-six Sprague-Dawley male rats were equally divided into eight groups: negative control, positive control (PC) with single-dose administration of CT contrast agent, and additional administration of either CT or MR contrast agents 2, 4, or 24 hours from initial CT contrast agent injection. A 12 µL/g of iodinated contrast agent or a 0.47 µL/g of gadolinium-based contrast agent were injected into the tail vein. Serum levels of blood urea nitrogen, creatinine, cystatin C (Cys C), and malondialdehyde (MDA) were measured. mRNA and protein levels of kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) were evaluated. Results: Levels of serum creatinine (SCr) were significantly higher in repeated CT contrast agent injection groups than in PC (0.21 ± 0.02 mg/dL for PC; 0.40 ± 0.02, 0.34 ± 0.03, and 0.41 ± 0.10 mg/dL for 2-, 4-, and 24-hour interval groups, respectively; P < 0.001). There was no significant difference in the average Cys C and MDA levels between PC and repeated CT contrast agent injection groups (Cys C, P = 0.256-0.362; MDA, P > 0.99). Additional doses of MR contrast agent did not make significant changes compared to PC in SCr (P > 0.99), Cys C (P = 0.262), and MDA (P = 0.139-0.771) levels. mRNA and protein levels of KIM-1 and NGAL were not significantly different among additional CT or MR contrast agent groups (P > 0.05). Conclusion: A sufficient time interval, probably more than 24 hours, between repeated contrast-enhanced CT examinations may be necessary to avoid deterioration in renal function. However, conducting contrast-enhanced MRI on the same day as contrast-enhanced CT may not induce clinically significant kidney injury.

• Journal of Veterinary Clinics
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• v.35 no.4
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• pp.146-149
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• 2018

A 7-year-old, castrated, male Maltese dog presented with hyporexia and depression for 3 days. Elevated serum amylase, lipase activities, and liver enzyme values were found upon blood examination. An abdominal mass was seen on radiographs caudal to the gastric body in the left middle abdomen. In the left middle abdomen, abdominal ultrasonography also revealed a massive, irregularly marginated, heterogeneous mass of unknown origin, and in the right cranial abdomen, heterogeneously hypoechoic pancreatic tissue and hyperechoic change of adjacent mesenteric fat were observed. Contrast-enhanced computed tomography showed an irregular contour of the left pancreatic limb as well as heterogeneously enhanced parenchyma. A low-attenuating peripancreatic fluid collection with a thin and irregular wall was also seen. Based on these findings, an atypical pancreatic abscess with necrotizing pancreatitis which manifested as walled-off necrosis was suspected. The mass was excised, and the pancreatic abscess was confirmed by histopathologic examination. No complications were found in the patient after two months of follow-up examination.

• Journal of Biomedical Engineering Research
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• v.26 no.3
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• pp.171-176
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• 2005

This paper proposes an automatic liver segmentation method using improved partial histogram threshold (PHT) algorithms. This method removes neighboring abdominal organs regardless of random pixel variation of contrast enhanced CT images. Adaptive multi-modal threshold is first performed to extract a region of interest (ROI). A left PHT (LPHT) algorithm is processed to remove the pancreas, spleen, and left kidney. Then a right PHT (RPHT) algorithm is performed for eliminating the right kidney from the ROI. Finally, binary morphological filtering is processed for removing of unnecessary objects and smoothing of the ROI boundary. Ten CT slices of six patients (60 slices) were selected to evaluate the proposed method. As evaluation measures, an average normalized area and area error rate were used. From the experimental results, the proposed automatic liver segmentation method has strong similarity performance as the MSM by medical Doctor.

• Journal of Korean Neurosurgical Society
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• v.66 no.2
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• pp.155-161
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• 2023

Objective : To analyze the anatomical location of the ureter in relation to lateral lumbar interbody fusion and evaluate the potential risk of ureteral injury. Methods : One hundred eight patients who performed contrast-enhanced computed tomographic scans were enrolled in this study. The location of the ureter from L2-L3 to L4-L5 was evaluated. The distances between the ureter and psoas muscle, intervertebral disc, and retroperitoneal vessels were also recorded bilaterally. Results : Over 30% of the ureters were close to the working corridor of extreme lumbar interbody fusion at L2-L3. Most of the ureters were close to working corridor of oblique lumbar interbody fusion, especially at L4-L5. The distance from the ureter to the great vessels on the left side was significantly narrowing from L2-L3 to L4-L5 (28.8±9.5 mm, 22.0±8.0 mm, 15.5±8.4 mm), and it was significantly larger than that on the right side (12.3±6.1 mm, 7.4±5.7 mm, 5.4±4.4 mm). Conclusion : Our findings indicate that the location of the ureter varies widely among individuals. To avoid unexpected damage to the ureter, it is imperative to directly visualize it and verify the ureter is not in the surgical pathway during lateral lumbar interbody fusion.

• Journal of Veterinary Clinics
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• v.27 no.6
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• pp.686-692
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• 2010

Computed tomography (CT) is considered as gold standard in evaluating pancreatitis in human, but there have been only a few studies in veterinary field. Balthazar CT severity index (CTSI) used to assess the severity of acute necrotizing pancreatitis in human could be applicable to dogs, because the severity of acute pancreatitis depends on the area of pancreatic necrosis in dogs more than in human. In this study, 25 adult, clinically healthy beagle dogs were used. CT examinations was performed in normal pancreas, positive control group and acute necrotizing pancreatitis induced by autologous bile injection. Balthazar CTSI was applied to canine acute necrotizing pancreatitis in contrastenhanced CT image and compared with the result of histopathologic examination. The Hounsfield unit (HU) of normal canine pancreas was $52.44{\pm}4.58$ and the density was significantly decreased in acute necrotizing pancreatitis (P < .05). In contrast-enhanced CT examination, pancreatic density was decreased significantly and this area was compatible to pancreatic necrosis. Balthazar CTSI showed positive correlation with histopathologic evaluation with a sensitivity of 100% and a specificity of 88.89%. Balthazar CTSI can be applied to evaluate the severity of acute necrotizing pancreatitis in dogs.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2521-2526
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• 2015

Objective: The purpose of this study was to evaluate computed tomography (CT) virtual non-contrast (VNC) spectral imaging for gastric carcinoma. Materials and Methods: Fifty-two patients with histologically proven gastric carcinomas underwent gemstone spectral imaging (GSI) including non-contrast and contrast-enhanced hepatic arterial, portal venous, and equilibrium phase acquisitions prior to surgery. VNC arterial phase (VNCa), VNC venous phase (VNCv), and VNC equilibrium phase (VNCe) images were obtained by subtracting iodine from iodine/water images. Images were analyzed with respect to image quality, gastric carcinoma-intragastric water contrast-to-noise ratio (CNR), gastric carcinoma-perigastric fat CNR, serosal invasion, and enlarged lymph nodes around the lesions. Results: Carcinoma-water CNR values were significantly higher in VNCa, VNCv, and VNCe images than in normal CT images (2.72, 2.60, 2.61, respectively, vs 2.35, $p{\leq}0.008$). Carcinoma-perigastric fat CNR values were significantly lower in VNCa, VNCv, and VNCe images than in normal CT images (7.63, 7.49, 7.32, respectively, vs 8.48, p< 0.001). There were no significant differences of carcinoma-water CNR and carcinoma-perigastric fat CNR among VNCa, VNCv, and VNCe images. There was no difference in the determination of invasion or enlarged lymph nodes between normal CT and VNCa images. Conclusions: VNC arterial phase images may be a surrogate for conventional non-contrast CT images in gastric carcinoma evaluation.

• Journal of Veterinary Science
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• v.24 no.2
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• pp.25.1-25.6
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• 2023

An eight-year-old Maltese dog presented with diarrhea and anorexia. Ultrasonography revealed marked focal wall thickening with loss of layering in the distal ileum. Contrast-enhanced computed tomography (CT) revealed a preserved wall layer with hypoattenuating middle wall thickening. In some segments of the lesion, small nodules protruding toward the mesentery from the outer layer were observed. Histopathology revealed focal lipogranulomatous lymphangitis (FLL) with lymphangiectasia. This is the first report to describe the CT features of FLL in a dog. CT features of preserved wall layers with hypoattenuating middle wall thickening and small nodules can assist in diagnosing FLL in dogs.

• Journal of Yeungnam Medical Science
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• v.28 no.2
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• pp.165-172
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• 2011

Gastric glomus tumor is a rare mesenchymal tumor that originates from modified smooth muscle cells of the glomus body. Glomus tumors are commonly observed in peripheral soft tissue, such as dennis or subungal region, but rarely in the gastrointestinal tract. A 39-year-old woman was admitted due to epigastric soreness. Upper gastrointestinal endoscopy revealed a subepithelial mass measuring 3.5 cm with central ulceration at the lesser curvature-posterior wall of the antrum. Characteristically, contrast enhanced abdominal computed tomography scan demonstrated high enhancement of the submucosal mass up to the same level of the abdominal aorta in the arterial phase; this enhancement persisted to delayed phase. Due to the risk of bleeding and malignancy, wedge resection of the submucosal tumor was performed. Histologic findings were compatible with a glomus tumor.

• Investigative Magnetic Resonance Imaging
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• v.25 no.4
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• pp.338-344
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• 2021

Solitary fibrous tumors (SFT) are rare mesenchymal tumors that most commonly develop in the pleura; they rarely involve the diaphragm. MRI has not been widely used to evaluate SFTs of the thoracic cavity, though it may be highly useful in assessing local invasion, predicting malignant potential, and helping in the differential diagnosis. However, MRI findings of malignant SFTs of the diaphragmatic pleura have been described in only two cases. We report a rare case of a malignant solitary fibrous tumor of the diaphragmatic pleura in an 82-year-old man. We describe the clinical and characteristic imaging features, including computed tomography, conventional MRI, and diffusion-weighted imaging. Contrast-enhanced MRI is more accurate than is CT in identifying the origin of SFTs, predicting whether they ae benign or malignant, and assessing local invasion. This imaging modality proved helpful in deciding on the treatment strategy for these rare tumors.