• Korean Journal of Radiology
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• 제2권1호
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• pp.14-20
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• 2001

Objective: To compare the usefulness of unenhanced spiral CT (UCT) with that of excretory urography (EU) in patients with acute flank pain. Materials and Methods: Thirty patients presenting with acute flank pain underwent both UCT and EU. Both techniques were used to determine the presence, size, and location of urinary stone, and the presence or absence of secondary signs was also evaluated. The existence of ureteral stone was confirmed by its removal or spontaneous passage during follow-up. The absence of a stone was determined on the basis of the clinical and radiological evidence. Results: Twenty-one of the 30 patients had one or more ureteral stones and nine had no stone. CT depicted 22 of 23 calculi in the 21 patients with a stone, and no calculus in all nine without a stone. The sensitivity and specificity of UCT were 96% and 100%, respectively. EU disclosed 14 calculi in the 21 patients with a stone and no calculus in eight of the nine without a stone. UCT and EU demonstrated secondary signs of ureterolithiasis in 15 and 17 patients, respectively. Conclusion: For the evaluation of patients with acute flank pain, UCT is an excellent modality with high sensitivity and specificity. In near future it may replace EU.

• 한국지능시스템학회:학술대회논문집
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• 한국지능시스템학회 2008년도 춘계학술대회 학술발표회 논문집
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• pp.255-258
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• 2008

For rapidly increasing amount of medical images, it is difficult for radiologist to interpretate the medical images fastly and for sufficient time. We investigated whether liver CT image has good features to be analyzed by computer algorithm, We examed the CT images of liver tumors (Hepetocellular carcinomas; HCCs) and searched any potential morphologic characteristics to be analyzed by computer algorithms. On unenhanced CT, HCCs appeared hypodense After enhancement, most HCCs were hyperdense, and then. as a consequence of rapid washout, HCCS became hypodense compared with the liver parenchyma. Most CT images of HCCs showed synchronous phase-specific.morphologic features. We applied various edge detection filters to these images and some filters showed favorable performance in the detection of tile edge of liver and HCC. Therefore, theses features seems to be analyzed by computer algorithms effectively.Further studies may be warranted.

• Journal of Veterinary Science
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• 제21권4호
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• pp.55.1-55.11
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• 2020

Background: Computed tomography urography (CTU), based on the excretion of contrast medium after its injection, allows visualization of the renal parenchyma and the renal collecting system. Objectives: To determine the optimal contrast medium dose allocation ratio to apply in split-bolus CTU in dogs. Methods: This prospective, experimental, exploratory study used 8 beagles. In 3-phase CTU, unenhanced-, nephrographic-, and excretory-phase images were obtained with a single injection of 600 mg iodine/kg iohexol. In split-bolus CTU, two different contrast medium allocation ratios (30% and 70% for split CTU 1; 50% and 50% for split CTU 2) were used. Unenhanced phase image and a synchronous nephrographic-excretory phase image were acquired. Results: Although the attenuation of the renal parenchyma was significantly lower when using both split CTUs than the 3-phase CTU, based on qualitative evaluation, the visualization score of the renal parenchyma of split CTU 1 was as high as that of the 3-phase CTU, whereas the split CTU 2 score was significantly lower than those of the two others. Artifacts were not apparent, regardless of CTU protocol. The diameter and opacification of the ureter in both split CTUs were not significantly different from those using 3-phase CTU. Conclusions: Split-bolus CTU with a contrast medium allocation ratio of 30% and 70% is feasible for evaluating the urinary system and allows sufficient enhancement of the renal parenchyma and appropriate distention and opacification of the ureter, with similar image quality to 3-phase CTU in healthy dogs. Split-bolus CTU has the advantages of reducing radiation exposure and the number of CT images needed for interpretation.

• Investigative Magnetic Resonance Imaging
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• 제5권2호
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• pp.149-154
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• 2001

목적 : 급성 거미막하 출혈의 진단에 있어 CT와 비교하여 fluid-attenuated inversion-recovery (FLAIR) MR영상의 유용성을 평가하고자 하였다. 대상 및 방법 : 증상 발생 3일 이내에 비조영 CT와 FLAIR MR영상을 모두 얻었던 28명의 급성 지주막하 출혈 환자를 대상으로 하였다. 거미막하 공간을 피질구, 실비우스열구, 기저조, 후두와의 4부위로 나누어 각 부위 별로 CT와 FLAIR영상에서 출혈이 보이는 정도를 0(출혈 없음), 1(출혈 의심), 2(뚜렷한 출혈)의 점수로 구분하여 평가하였다. 또한 이들 28명 환자와 대조군 35명의 FLAIR영상을 비교하여 거미막하 공간의 고신호 강도를 기준으로 출혈의 유무를 판정할 경우, FLAIR영상의 민감도, 특이도 및 진단적 정확도를 평가하였다. 결과 : FLAIR영상에서 급성 거미막하 출혈은 모든 환자에서 뇌척수액이나 뇌 실질보다 고신호 강도를 보여 100%의 발견율을 보였다. CT와 비교하여 피질구($1.11{\pm}0.80$ vs $0.70{\pm}0.83$: p(0.05)와 후두와($1.41{\pm}0.74$ vs $0.78{\pm}0.80$: p(0.05)에서 FLAIR영상이 CT보다 통계적으로 유의하게 우수하였다 FLAIR영상에서 거미막하 공간의 고신호 강도를 기준으로 거미막하 출혈 유무를 평가한 결과에서 100%의 민감도, 특이도 및 진단적 정확도를 보였다. 결론 급성 거미막하 출혈의 진단에 FLAIR MR영상은 매우 유용하며, 특히 출혈의 양이 소량인 경우와 후두와의 출혈을 진단하는데 CT보다 우수하다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권6호
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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.

• 한국임상수의학회지
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• 제35권2호
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• pp.53-56
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• 2018

Computed tomography (CT) findings of hepatic adenoma in veterinary medicine are variable and unlike in human medicine, not defined clearly. A 12-year-old neutered male Shih Tzu presented after a seizure, with weight loss, salivation, and cachexia. An abdominal mass was identified on radiography, and ultrasonographic images showed a mixed echo pattern with marked vascularity. CT showed that the mass originated from caudate lobe, was heterogeneously hypoattenuated compared with the hepatic parenchyma, and had irregular margins. Contrast enhanced CT showed that the mass enhanced like the surrounding liver parenchyma. However, it contained unenhanced areas and enhanced vessels were observed in the arterial phase at the periphery of the mass. The margins of mass were more enhanced in the venous phase than the arterial phase and the hypoattenuating regions within the mass were not enhanced. Greater enhancing in the venous phase is seen with adenomas; however, the heterogeneous enhancement pattern, especially the marginal vascular enhancement and internal hypoattenuating regions, is seen with malignancy. Although this is a single case of hepatic adenoma, the atypical enhanced pattern of this case can provide useful information to predict the malignancy of primary liver tumor.

• Korean Journal of Radiology
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• 제21권7호
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• pp.838-850
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• 2020

Computed tomography (CT) is an important imaging modality in evaluating thoracic malignancies. The clinical utility of dual-energy spectral computed tomography (DESCT) has recently been realized. DESCT allows for virtual monoenergetic or monochromatic imaging, virtual non-contrast or unenhanced imaging, iodine concentration measurement, and effective atomic number (Z_eff map). The application of information gained using this technique in the field of thoracic oncology is important, and therefore many studies have been conducted to explore the use of DESCT in the evaluation and management of thoracic malignancies. Here we summarize and review recent DESCT studies on clinical applications related to thoracic oncology.

• Korean Journal of Radiology
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• 제1권2호
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• pp.104-109
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• 2000

Objective: Multilocular cystic renal cell carcinoma (MCRCC) is a recently described variety of renal cell carcinoma with characteristic pathologic and clinical features. The purpose of this study was to analyze the imaging findings of MCRCCs. Materials and Methods: Ten adult patients with pathologically proven unilateral MCRCC who underwent renal US and CT were included in this study. The radiologic findings were retrospectively evaluated for cystic content, wall, septum, nodularity, calcification and solid portion by three radiologists who established a consensus. Imaging and postnephrectomy pathologic findings were compared. Results: All patients were adults (six males and four females) and their ages ranged from 33 to 68 years (mean, 46). On US and CT images, all tumors appeared as well-defined multilocular cystic masses composed of serous or complicated fluid. In all patients, unenhanced CT scans revealed hypodense cystic portions, and in four tumors, due to the presence of hemorrhage or gelatinous fluid, some hyperdense areas were also noted. In no tumor was an expansile solid nodule seen in the thin septa, and in only one was there dystrophic calcification in a septum. Small areas of solid portion constituting less than 10% of the entire lesion were found in six of the ten tumors, and these areas were slightly enhanced on enhanced CT scans. In all patients, imaging and pathologic findings correlated closely. Conclusion: On US and CT images, MCRCC appeared as a well-defined multilocular cystic mass with serous, proteinaceous or hemorrhagic fluid, with no expansile solid nodules in the thin septa, and sometimes with small slightly enhanced solid areas. Where radiologic examinations demonstrate a cystic renal mass of this kind in adult males, MCRCC should be included in the differential diagnosis.

• Journal of Yeungnam Medical Science
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• 제25권2호
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• pp.102-107
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• 2008

배경 : 고립성 폐결절의 30~40%는 악성결절의 가능성이 높다. 따라서 고립성 폐결절의 악성감별이 무엇보다 중요하다. 최근 dynamic CT가 악성 감별에 많이 사용되며, 또한 그 중요성이 커지고 있다. 이 연구의 목적은 dynamic CT의 혈역동학적 특성들을 비교하여 고립성 폐결절의 악성 여부를 구별하는데 유용한 지표인지 알아보기 위한 것이다. 재료 및 방법 : 2005년 12월부터 2006년 4월까지 고립성 폐결절로 내원한 환자 19명을 대상으로 하였다. Dynamic CT에서는 조영 전, 그리고 조영제를 주입한 후 20초, 40초, 60초, 80초, 100초, 120초, 140초, 160초, 180초의 영상을 촬영하였다. 대상 환자 모두 경피세침술로 조직검사를 하였다. Levene's test를 이용하여 조직검사로 확인된 양성결절과 악성결절에서 dynamic CT의 최대조영증강, 순수조영증강, 조영증강의 기울기, 최대상대조영증강비의 차이를 비교하였다. 결과 : 조직검사 결과 12명이 악성결절로 확인되었고, 7명은 양성결절로 진단되었다. 최대조영증강(p=0.787), 순수조영증강(p=0.135), 조영증강의 기울기(p=0.698)는 양성결절과 악성결절 사이에 통계학적으로 유의한 차이를 보이지 않았다. 최대상대조영증강비는 양성결절보다 악성결절이 더 높은 경향이었으나 통계적인 유의성은 없었다(p=0.094). 결론 : 본 연구에서는 dynamic CT에 주로 이용되는 혈역동학적 특성들로 양성결절과 악성결절의 차이를 확인할 수 없었다. 따라서 많은 수의 환자를 대상으로 한 연구가 필요하며 또한 조영제를 주입한 후 영상을 좀 더 오랜시간동안 측정하였을 때 보다 정확한 연구결과를 얻을 것으로 생각된다.

• Korean Journal of Radiology
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• 제22권5호
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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.