Published papers

Some renal masses have higher attenuation than the surrounding renal parenchyma at computed tomography (CT). Their hyperattenuation is usually the result of proteinaceous fluid or densely packed cells. Most hyperattenuating renal masses are benign hemorrhagic or proteinaceous cysts. However, solid enhancing hyperattenuating renal masses may have malignant as well as benign causes. Possible malignant causes include renal cell carcinoma and lymphoma; benign causes include angiomyolipoma with minimal fat. It is important to identify the cause of a hyperattenuating renal mass so as to avoid unnecessary surgical resection or ablation. CT may be useful for diagnosing benign hyperattenuating renal cysts, hematomas, and vascular anomalies that appear masslike. However, some solid, enhancing, hyperattenuating masses cannot be diagnosed confidently with CT alone: Small (≤3-cm-diameter), homogeneously enhancing, hyperattenuating renal masses depicted on CT images may be either benign angiomyolipomas with minimal fat or renal cell carcinomas. Magnetic resonance (MR) imaging may be helpful for differentiating between angiomyolipomas with minimal fat and clear cell renal cell carcinomas; however, differentiation between angiomyolipomas with minimal fat and papillary renal cell carcinomas often is not possible on the basis of MR imaging. In such cases, a percutaneous biopsy may be useful for diagnosis. If the results of MR imaging and percutaneous biopsy are not definitive, surgery is warranted. ©RSNA, 2007.

OBJECTIVE. In a small pilot study, we assessed whether early-phase dynamic contrast-enhanced MDCT can be used to detect bladder tumors and whether thin reconstruction improves the detection rate. SUBJECTS AND METHODS. Thirty-six patients (30 with 59 cystoscopy-proven bladder cancers and six with normal bladders) underwent dynamic contrast-enhanced MDCT of the pelvis and abdomen. Images were obtained from the symphysis pubis to the diaphragm 70 seconds after injection of 100 mL of contrast medium. McNemar test was used to compare sensitivity per patient, segment, and tumor and specificity per patient and segment for each of three reconstruction methods: 5-mm sections with no overlap (i.e., 5-mm axial images), 2.5-mm sections with 1.25-mm overlap (i.e., thin-section axial images), and 2.5-mm sections with 1.25-mm overlap and multiplanar reformation (MPR) (i.e., thin-section axial images with MPR). RESULTS. MDCT with a combination of thin, overlapped sections and MPR depicted all but one of 47 bladder tumors larger than 5 mm but only five of 12 tumors 5 mm or smaller. There were no false-positive findings. Per-tumor sensitivity was significantly better with thin-section images with MPR (90%) and thin-section images alone (86%) than with 5-mm axial images (80%) (p < 0.05). Per-segment sensitivity was significantly better with thin-section images with MPR (95%) and thin-section axial images alone (87%) than with 5-mm axial images (79%) (p < 0.05). Per-patient sensitivity and per-patient and per-segment specificity did not differ with the three methods. CONCLUSION. Dynamic contrast-enhanced MDCT of the pelvis shows promise for the detection of bladder tumors. Use of thin-section images with MPR and thin-section axial images alone had a significantly better rate of detection of bladder tumors than use of 5-mm axial images. © American Roentgen Ray Society.

64-slice CT enabled the improved image quality of patients with high heart rate, the stabilization of heart rate during scan, volume reduction of contrast media, and wider coverage of ECG-gated scan compared with 16-slice CT. These advantages reduce the motion artifact, increase the percentage of assessable segments, and widen its clinical application. However, evaluation of lesions with severe calcification is still the limitation, that needs to be overcome with further technical advancement.

The imaging findings of a solitary fibrous tumor of the prostate are presented. A 35-year-old male presented with urinary retention and was found on transrectal ultrasonography to have a hypoechoic tumor of the prostate, measuring 5.5 cm in size. Magnetic resonance imaging on, the tumor showed low signal intensity on T1-weighted images and heterogeneous mixed signal intensity on T2-weighted images. Gadolinium-enhanced dynamic study showed gradual enhancement from the periphery to the center, and the enhancement is sustained. On immunohistochemistry, the spindle cells of the tumor showed positive staining for CD34 and bcl-2. Although the tumor was labeled as a low-grade malignancy on account of a low mitotic index (MIB-1 index) of about 5%, the patient developed local recurrence of the tumor with bladder wall invasion 12 months later. © 2006 Elsevier Inc. All rights reserved.

OBJECTIVE. The purpose of this study was to compare the accuracy of CT urography and excretory urography for the detection and localization of upper urinary tract urothelial carcinoma. MATERIALS AND METHODS. Of 128 patients at high risk for upper tract urothelial carcinoma who were examined with both CT urography and excretory urography between 2002 and 2007, 24 were undiagnosed and excluded. CT urography and excretory urography results of the remaining 104 patients and 552 urinary tract segments were compared with histopathologic examination or followup imaging at 1 year. Two readers independently scored the confidence levels for the presence or absence of upper urinary tract urothelial carcinoma in each of six upper urinary tract segments on both CT urography and excretory urography; differences were resolved by consensus. RESULTS. Upper urinary tract urothelial carcinoma was diagnosed in 77 (14%) segments of 46 (44%) patients. Perpatient sensitivity, specificity, overall accuracy, and area under the receiver operating characteristic curves for detecting carcinomas with CT urography (93.5% [43/46], 94.8% [55/58], 94.2% [98/104], and 0.963, respectively) were significantly greater than those for excretory urography (80.4% [37/46], 81.0% [47/58], 80.8% [84/104], and 0.831, respectively) (p = 0.041, p = 0.027, p = 0.001, and p < 0.001, respectively). Persegment sensitivity and overall accuracy for the localization of upper urinary tract urothelial carcinoma were significantly greater with CT urography (87.0% [67/77] and 97.8% [540/552]) than with excretory urography (41.6% [32/77] and 91.5% [505/552]) (p < 0.0001). CONCLUSION. CT urography was more accurate than excretory urography in the detection and localization of upper urinary tract urothelial carcinoma and should be considered as the initial examination for the evaluation of patients at high risk for upper urinary tract urothelial carcinoma. © American Roentgen Ray Society.

Objective: The purpose of this study was to compare the accuracy of CT urography and excretory urography for the detection and localization of upper urinary tract urothelial carcinoma. Materials and Methods: Of 128 patients at high risk for upper tract urothelial carcinoma who were examined with both CT urography and excretory urography between 2002 and 2007, 24 were undiagnosed and excluded. CT urography and excretory urography results of the remaining 104 patients and 552 urinary tract segments were compared with histopathologic examination or follow-up imaging at 1 year. Two readers independently scored the confidence levels for the presence or absence of upper urinary tract urothelial carcinoma in each of six upper urinary tract segments on both CT urography and excretory urography; differences were resolved by consensus. Results: Upper urinary tract urothelial carcinoma was diagnosed in 77 (14%) segments of 46 (44%) patients. Per-patient sensitivity, specificity, overall accuracy, and area under the receiver operating characteristic curves for detecting carcinomas with CT urography (93.5% [43/46], 94.8% [55/58], 94.2% [98/104], and 0.963, respectively) were significantly greater than those for excretory urography (80.4% [37/46], 81.0% [47/58], 80.8% [84/104], and 0.831, respectively) (p = 0.041, p = 0.027, p = 0.001, and p < 0.001, respectively). Persegment sensitivity and overall accuracy for the localization of upper urinary tract urothelial carcinoma were significantly greater with CT urography (87.0% [67/77] and 97.8% [540/552]) than with excretory urography (41.6% [32/77] and 91.5% [505/552]) (p < 0.0001). Conclusion: CT urography was more accurate than excretory urography in the detection and localization of upper urinary tract urothelial carcinoma and should be considered as the initial examination for the evaluation of patients at high risk for upper urinary tract urothelial carcinoma.

A 68-year-old man underwent total cystectomy, urethrectomy preserving fossa naviculars, and an Indiana pouch urinary diversion in 1997. The histopathology was UC, G3, pT4 (prostate). Nine years after the operation, he had multiple metastases to the inguinal and paraaortic lymph nodes (LNs), and he complained of erosion around the glans. Histological diagnosis of the glans revealed recurrent UC to the urethra of the glans. We considered the possibility that the inguinal LN metastasis was due to lymphatic spread from a remnant urethral recurrence. Thus, a partial penectomy and inguinal LN dissection were undertaken. Systemic chemotherapy was administered. Remnant urethral recurrence after urethrectomy preserving the fossa navicularis and inguinal LN metastasis are rare. © 2011 Japanese Urological Association.

Angiomyolipoma with epithelial cysts (AMLEC), which has not only a stromal component but an epithelial component, is a rare cystic variant of AML. We present a case of a man in his forties with microscopic hematuria, who had a multilocular cystic tumor in his left kidney. He underwent laparoscopic partial nephrectomy and the tumor was diagnosed as AMLEC histopathologically. We chiefly report the radiologic features of this tumor.

A 74-year-old male underwent cardiac catheterization that revealed a chronic total occlusion of the proximal left anterior descending coronary artery (LAD). The right coronary artery provided only faint collateral circulation to the LAD. Multislice computed tomography (MDCT) disclosed that a conus artery took off directly from the aorta and provided good collateral circulation to the LAD. Percutaneous coronary intervention of the LAD was successfully performed using contralateral injection via the isolated conus artery. Whenever sufficient collateral filling is not visualized in a chronically occluded LAD, an isolated conus artery should be considered. MDCT is a helpful tool in this setting.

Background/Aims: Early evaluations of patients presenting with acute chest pain remain difficult. We examined the diagnostic capacity of multidetector computed tomography (MDCT) for acute coronary syndrome (ACS) in patients presenting with acute chest pain. Methods/Results: We examined 36 consecutive patients presenting with acute chest pain with neither diagnostic ECG changes nor elevated biomarkers. 64-slice MDCT was performed, and we evaluated the presenceof significant coronaryartery stenosis (>50% reduction in lumen diameter). Significant stenosis was detected in 15 patients by MDCT. Among them, 11 patients were diagnosed as having ACS based on the findings of coronary angiography or myocardial perfusion single photon emission computed tomography (positive predictive value 73%). All 21 patients without significant stenosis by MDCT, except only one, were regarded as not having ACS (negative predictive value 95%). Sensitivity and specificity were 92 and 83%, respectively. In patients without a history of coronary artery disease (CAD), both the specificity and positive predictive value improved to 100% (sensitivity 90%; negative predictive value 95%). In patients with neither a history of CAD nor coronary calcification, the diagnostic accuracy of MDCT was 100%. Conclusions: MDCT has high diagnostic capacity for the early evaluation of ACS, especially in patients without a history of CAD or coronary calcification. Copyright © 2008 S. Karger AG.

On rare occasions, extrinsic compression of the coronary artery can cause significant stenosis. We report a 42-year-old woman who was referred to our hospital for surgical repair of atrial septal defect. Cardiac 64-slice multi-detector computed tomography before the operation revealed the extrinsic compression of the proximal left main coronary artery by the marked dilatation of pulmonary trunk. The patient eventually underwent atrial septal defect closure and coronary artery bypass simultaneously. Four months after the operation, multi-detector computed tomographic scan revealed reduction of pulmonary trunk diameter and resolution of left main coronary artery narrowing. © 2008 The Society of Thoracic Surgeons.

Purpose: To evaluate the MRI findings of retroperitoneal low-flow vascular malformations (RLVMs) correlated with histopathological findings. Methods: Two radiologists reviewed the MRI findings of 4 RLVMs (3 with capillary malformations and 1 with a venous malformation). First, they evaluated the visibility, signal intensities, and signal homogeneity of each lesion on non-fat-suppressed breath-hold T2-weighted single-shot fast spin-echo (non-FS SSFSE) images and fat-suppressed T2-weighted fast spin-echo (FS T2-weighted FSE) images. Second, the kinetic patterns and the internal enhancement patterns were analyzed for each lesion on multi-phasic contrast-enhanced (CE) images. After these image analyses, the MRI findings were correlated with the histopathological findings. Result: Histopathologically, the 4 RLVMs did not exhibit remarkable degeneration and were present in the retroperitoneal fat tissue without clear capsules. On the non-FS SSFSE images, 3 of the 4 RLVMs could not be discriminated from the surrounding retroperitoneal fat tissue (invisible), and the remaining lesion was barely visible with an indistinct margin. On the FS T2-weighted FSE images, however, all the RLVMs were clearly visualized as homogeneous high-signal intensities. On the multi-phasic CE images, all the capillary malformations exhibited fast enhancement, while a venous malformation showed slow enhancement. Furthermore, the RLVMs tended to exhibit a centripetal filling pattern. Conclusion: The RLVMs blended in with the surrounding retroperitoneal fat tissue on non-FS SSFSE images, like phantoms, whereas they were clearly visualized on FS T2-weighted FSE images. On multi-phasic CE images, the RLVMs tended to exhibit a centripetal filling pattern. These imaging features may be useful diagnostic clues for RLVMs.