Clinical-radiologic correlation of mixed epithelial and stromal tumor of the kidneys: Cases analysis.

BACKGROUND: Mixed epithelial and stromal tumor of the kidney (MESTK) is a rare tumor, with few malignant cases reported. Occurring mostly in middle-aged women, it is characterized by a biphasic pathological structure. METHODS: This study retrospectively reviewed the imaging findings and medical records of six MESTK cases of a single institution in a 10-year period. RESULTS: All of the patients were middle-aged women without hormone therapy history. The typical image was a renal tumor with varied cystic components. Half of the cases had sinus invagination, but only one had intratumor calcification. On imaging studies, four were Bosniak Category IV, one was Category III, and one presented as a solid tumor. The mean RENAL nephrometry score was 9.3. Five patients underwent partial nephrectomy, with no statistical renal functional deterioration after nephron-sparing surgery. There were no peri-operative complications. CONCLUSION: Surgery remains the treatment of choice for MESTK, and nephron-sparing surgery should be considered in feasible cases.

Percutaneous computed tomography-guided cryoablation for renal tumor: Experience in 30 cases.

BACKGROUND: Percutaneous cryoablation is a minimally invasive alternative for surgical resection of a renal tumor. We report our experience with applying computed tomography-guided cryoablation in renal tumors, focusing on the technique, safety, and treatment response. METHODS: We retrospectively reviewed the medical records of patients who received cryoablation from October 2009 to August 2013 for renal tumor diagnosed by imaging studies performed at Taipei Veterans General Hospital, Taipei, Taiwan. Patient comorbidities and tumor morphology, technical success rate, tumor control rate, renal function change, and complications were recorded. RESULTS: A total of 30 patients (32 tumors) were treated, comprising 30 renal cell carcinomas and two angiomyolipomas. The mean age of the patients was 73.7 years (range, 34-89 years). The patients were referred for percutaneous cryoablation arising from old age, medical comorbidities, or preexisting malignancy. The mean follow-up period was 15.2 months (range, from 32 days to 47.4 months). According to the Clavien-Dindo classification, surgical complications included one Grade III, four Grade II, and two Grade I complications. The mean decrease in hemoglobin was 0.77 g/dL (range, from +1.1 g/dL to -3 g/dL). The mean hospital stay after cryoablation was 2.2 days (range, 1-10 days). Incomplete ablation was noted in two patients and local tumor recurrence in two patients. One of them received repeated cryoablation and achieved successful local control. Of the 22 renal cell carcinoma patients with follow-up period > 6 months, 19 patients achieved successful local tumor control (86.4%). The percentage change of glomerular filtration rate before and 3-6 months after the procedure was +1.9%, which was statistically nonsignificant (p = 0.94). CONCLUSION: Computed tomography-guided percutaneous cryoablation is a safe and effective technique for treating renal tumors with excellent renal function preservation.

Evaluation of the extent of ketamine-induced uropathy: the role of CT urography.

BACKGROUND: With growing ketamine abuse, ketamine-induced uropathy (KIU) has become more prevalent in recent years. This research evaluates the presence, distribution and extent of KIU in the upper and lower urinary tracts by retrospectively reviewing CT urography (CTU) images. METHODS: Patients diagnosed with KIU who underwent CT scanning from 1 January 2006 to 31 December 2011 were recruited. The CT protocols included three-phase CTU in six patients, split-bolus CTU in 17, two-phase CT in one and unenhanced CT in three. The CT images were retrospectively reviewed by two radiologists. RESULTS: A total of 27 patients participated in this study. The common CT findings included diffuse bladder wall thickening (88.9%), small bladder volume (66.7%) and perivesical inflammation (44.4%). Twelve patients (44.4%) were diagnosed with hydronephrosis, including three patients with unilateral hydronephrosis and nine with bilateral hydronephrosis. Of these patients, nine had ureteral wall thickening (33.3%) and two (7.4%) had ureterovesical junction involvement (ie, they had hydronephrosis but no ureteral wall thickening). One patient had a ureteral obstruction because of a ureter stone. The correlation between upper urinary tract involvement and grading of the interstitial cystitis was statistically non-significant (p=0.33). Four patients (14.8%) had a vesicovaginal fistula which could be detected in the excretory phase only. CONCLUSIONS: Upper urinary tract involvement is common in patients with KIU. CTU might aid evaluation of the extent of KIU and prompt adequate management.

Are there useful CT features to differentiate renal cell carcinoma from lipid-poor renal angiomyolipoma?

OBJECTIVE: This study was an attempt to identify key CT features that can potentially be used to differentiate between lipid-poor renal angiomyolipoma and renal cell carcinoma (RCC). MATERIALS AND METHODS: We conducted an analysis of patients who received nephrectomy or renal biopsy from 2002 to 2011 with suspected RCC. We included tumors smaller than 7 cm with a completed three-phase CT examination. A radiologist and a urology fellow, blinded to histopathologic diagnosis, recorded the imaging findings by consensus and compared the values for each parameter between lipid-poor angiomyolipoma, RCC subtypes, and RCC as a group. Multivariate logistic regression analysis was performed for each univariate significant feature. RESULTS: The sample in our study consisted of 132 patients with 135 renal tumors, including 51 men (age range, 26-84 years; mean age, 57 years) and 81 women (age range, 29-91 years; mean age, 57 years). These tumors included 33 lipid-poor angiomyolipomas, 54 clear-cell RCC, 31 chromophobe RCC, and 17 papillary RCC. Multivariate analysis revealed four significant parameters for differentiating RCC as a group from lipid-poor angiomyolipoma (angular interface, p = 0.023; hypodense rim, p = 0.045; homogeneity, p = 0.005; unenhanced attenuation > 38.5 HU, p < 0.001), five for clear-cell RCC, two for chromophobe RCC, and one for papillary RCC. Lipid-poor angiomyolipoma and clear-cell RCC showed early strong enhancement and a washout pattern, whereas chromophobe RCC and papillary RCC showed gradual enhancement over time. CONCLUSION: Specific CT features can potentially be used to differentiate lipid-poor renal angiomyolipoma from renal cell carcinoma.

Parallel second stent placement for refractory ureteral stent malfunction in malignant ureteral obstruction.

PURPOSE: To review retrospectively the outcome of placement of a parallel second ureteral stent in patients with urinary obstruction secondary to a malignancy. MATERIALS AND METHODS: During the period 2005-2008, the medical records of patients with ureteral obstruction from an abdominal malignancy were reviewed. Patients who experienced malfunction of the first ureteral stent subsequently underwent either initial stent exchange (control group) or a parallel second ureteral stent placement. The outcomes of both groups were evaluated in terms of stent function at 1 week, 1 month, and 3 months after the procedure. Several clinical and imaging parameters were also compared between the two groups. RESULTS: The stent malfunction rate increased more rapidly in the control group. In 1 week, the malfunction rate was 29.4% in the parallel ureteral stent group and 56.7% in the control group. By the end of the third month, the malfunction rate was 72.7% in the parallel ureteral stent group and 100% in the control group. The creatinine level after the procedure was significantly lower in the parallel ureteral stent group (P = 0.004). The incidence of symptomatic urinary tract infection (UTI) was around 30% in both groups (P = 1.000). CONCLUSIONS: Parallel second ureteral stent placement has a high technical success rate. For terminally ill patients who have a malignancy and an occluded ureteral stent, the technique can effectively relieve obstruction and prolong the function of the stent.

Diffusion-weighted single-shot echo-planar imaging with parallel technique in assessment of endometrial cancer.

OBJECTIVE: The purposes of this study were to determine the feasibility of diffusion-weighted imaging (DWI) with a single-shot echo-planar sequence and parallel technique for depicting endometrial cancer and to examine the role of this technique in preoperative assessment. SUBJECTS AND METHODS: A total of 31 patients were recruited for MRI evaluation of suspicious endometrial lesions found on transvaginal sonography. Twenty-four of the patients were proved to have endometrial cancer (patient group), and seven to have benign diseases (control group). The MRI examinations included diffusion-weighted single-shot echoplanar sequences and contrast-enhanced T1-weighted 3D fat-suppressed spoiled gradient-echo sequences. The apparent diffusion coefficient of endometrial cancer in the patient group and of normal endometrium in the control group were measured on the apparent diffusion coefficient map of each diffusion-weighted image and compared for the two groups. In the patient group, myometrial invasion was evaluated with the two sequences. The diagnostic accuracy rates of each pulse sequence were compared. RESULTS: The mean apparent diffusion coefficient of endometrial cancer was 0.864 x 10(-3) mm2/s and that of benign endometrial lesions was 1.277 x 10(-3) mm2/s. The difference between the two groups was significant (p = 0.0058). The diagnostic accuracy for myometrial invasion was 61.9% for DWI and 71.4% for gadolinium-enhanced T1-weighted 3D fat-suppressed spoiled gradient-recalled echo images. In five cases, DWI provided information about tumor extent and depicted the tumor focus, findings that changed preoperative staging. CONCLUSION: DWI performed with parallel imaging technique has potential as a method for differentiating benign from malignant endometrial lesions. It also provides valuable information for preoperative evaluation and should be considered part of routine preoperative MRI evaluation for endometrial cancer.

Prospective comparison of unenhanced spiral computed tomography and intravenous urography in the evaluation of acute renal colic.

BACKGROUND: The purpose of this prospective study was to evaluate the feasibility of replacing intravenous urography (IVU) with unenhanced computed tomography (CT) as the first line diagnostic modality for acute renal colic in the emergency department. METHODS: In the 1-year study period, 82 patients who presented themselves to the emergency room with acute renal colic and who were suspected to have ureteral stones were included. They received both IVU and unenhanced CT on the same day. RESULTS: Sixty-six patients were proven to have ureteral stone. Four had other urologic pathology (acute pyelonephritis, angiomyolipoma with hemorrhage, ureteropelvic junction stenosis). The remaining 12 had no definite urologic problem. Among the 66 patients with ureteral stone, the sensitivity for detecting ureteral stone was 98.5% for unenhanced CT and 59.1% for IVU. Correct diagnosis could be obtained in most of the patients receiving unenhanced CT, while IVU could provide only limited information about the intra-abdominal pathology other than urologic system, and as many as 31.7% of the patients needed further imaging examination (sonography, CT, magnetic resonance imaging). In 5 patients, the relationship of the calcified spot and ureter were unclear on axial images. With curved multiplanar reformatted reconstruction, the diagnosis of ureter stone could be confidently made. No side effect (renal toxicity, allergic reaction) from intravenous administration of iodine-containing contrast medium should be taken into consideration in CT. Besides, the average examination time was 108 minutes for IVU, which was significantly more than the 30 minutes for CT, including the time for curved multiplanar reformatted reconstruction. CONCLUSION: We consider that unenhanced CT is more effective and efficient than IVU and should replace IVU as the first-line diagnostic tool for ureteral stone in the emergency department.

Bowel preparation of outpatients for intravenous urography: efficacy of castor oil versus bisacodyl.

The purpose of this study was to compare the efficacy of two laxatives, castor oil and bisacodyl, in the routine bowel preparation of outpatients for intravenous urography (IVU). We used castor oil in patients undergoing IVU for 1 month, and then used bisacodyl in patients undergoing IVU for another month. Two uroradiologists, unaware of the method of bowel preparation, reviewed the standard radiographs and graded the residue in the large bowel and the clearness of the opacified urinary collecting system. In total, 71 consecutive outpatients received castor oil, and 84 received bisacodyl. For the castor oil group, grades from the two uroradiologists did not differ in terms of fecal residue on plain abdominal images (p = 0.54), and visualization of the urinary system on the left (p = 0.36) and right sides (p = 0.63). Findings were similar for bisacodyl recipients (p = 0.11, 0.59, and 0.32, respectively). When the laxative effect of the two agents was compared, we found no difference in the grading of fecal residue on plain abdominal images (p = 0.14), or in visualization of the urinary system on the left (p = 0.31) and right sides (p = 0.98). In conclusion, we observed no difference in laxative efficacy between castor oil and bisacodyl; thus, bisacodyl may be a useful alternative for bowel preparation before IVU.

Percutaneous radiofrequency ablation of renal cell carcinoma.

BACKGROUND: Preliminary data regarding the use of percutaneous radiofrequency ablation (RFA) for the treatment of renal cell carcinoma (RCC) are encouraging, and show the technique to be associated with minimal morbidity. Thus, the current study was designed to evaluate the clinical applications, treatment efficacy, and complications of percutaneous RFA in RCC. METHODS: From February 2003 to February 2004, 12 consecutive patients with histopathologically proven RCC underwent imaging-guided percutaneous RFA. The mean age of the patients (8 men and 4 women) was 76 years (range, 56-87 years), and mean tumor diameter was 3.7 cm (range, 2.2-8.0 cm). The efficacy of RFA was evaluated with contrast-enhanced, dynamic computed tomography (CT) performed 1 month after treatment, and then every 3 months. A Radionics device with an internally cooled electrode was used in 7 patients, and a radiofrequency interstitial tissue ablation (RITA) device with an expandable needle electrode was used in 5. Complete necrosis was defined as a lack of contrast enhancement in the treated region on follow-up CT studies. RESULTS: Overall, 16 sessions of RFA were performed for 12 solitary renal tumors in 12 patients: 8 patients underwent a single RFA session, whereas 4 had 2 sessions. Dynamic CT after RFA showed complete necrosis in 9 of 12 tumors. In 3 patients with tumors of 4.5-8.0 cm in diameter, enhancement of residual tissue was observed after RFA treatment, thus indicating residual tumor. Complete tumor necrosis was seen in all 5 tumors (100%) of diameter < or = 3.0 cm; 3 of 4 tumors (75%) of diameter 3.1-5.0 cm; and 1 of 3 tumors (33%) of diameter > 5.0 cm. A big subcapsular hematoma, which was found in 1 patient after RFA, resolved completely within 10 months without treatment; no serious complications occurred in the other 11 patients. CONCLUSION: Percutaneous RFA is effective in the treatment of RCC. It is most successful for tumors not larger than 3 cm in diameter, and has a satisfactory success rate in tumors of 3-5 cm in diameter. The rate of serious complications of RFA is low. Further studies are necessary to determine the long-term efficacy of RFA in RCC.

Prostatic abscess: transrectal color Doppler ultrasonic diagnosis and minimally invasive therapeutic management.

The purpose of this study was to analyze the transrectal ultrasound (US), or TRUS, and color Doppler ultrasonography (CDU) findings and therapeutic strategies with TRUS-guided procedures in 13 patients with prostatic abscess. Over a period of 6 years, 18 prostatic abscesses were diagnosed in 13 patients (mean age: 59 years). Diagnostic workup included TRUS, analysis of midstream urine, and analysis and culture of abscess fluid for leukocytes and pathogens. These patients were treated either conservatively (for abscess cavities < 1 cm in diameter), or by aspiration or draining procedures (cavities > or = 1 cm). The transrectal CDU findings were correlated to the treatment effects. The predisposing factors were also reviewed. In the 13 patients, the most common clinical symptom and sign were urinary frequency (77%) and pus cell in the midstream urine (92%). Predisposing factors were found in 11 men, with diabetes in 5 of them. In 10 patients, the definitive preinterventional diagnosis was based on the TRUS findings. TRUS with probe palpation demonstrated tiny floating echogenic speckles in the abscess cavity in 4 patients. CDU demonstrated increased color-flow signals at the margin and surrounding tissue of the abscess pockets. Abscesses with poorly defined boundaries had more prominent surrounding color-flow signals and achieved, with relative difficulty, a satisfactory aspiration procedure. Aspiration was done for all 11 abscesses between 1 and 3 cm. A total of 4 larger abscesses (> 3.0 cm) were treated with aspiration or drainage using a 5-French pigtail catheter. No surgical drainage was performed. Transrectal CDU may help in the evaluation of maturity of an abscess pocket. US-guided aspiration with an 18-gauge needle or drainage with a 5-French pigtail catheter significantly shortened the hospital stay.

Assessment of CT urography in the diagnosis of urinary tract abnormalities.

BACKGROUND: To evaluate the accuracy of helical computerized tomography urography (CTU) in diagnosing urinary tract disease. METHODS: We collected 102 patients who underwent CTU from March 2001 to September 2002. The clinical symptoms of these patients included: flank pain or hematuria, which were clinically suggestive of urinary system disorders. All patients received CT scan with or without intravenous contrast medium administration, except patients who had allergy history or poor renal function. Reformatted CT urography was performed and the accuracy of imaging diagnosis was evaluated. RESULTS: Of these 102 patients, 40 cases were proved to have urolithiasis, 24 cases were with renal or ureteral tumors, and there were 38 cases of other urinary system disorders (including inflammation, ureteral stricture and congenital anomalies). Precontrast CTU correctly diagnosed 39 of 40 urolithiasis cases (97.5%). Precontrast and contrast-enhanced CTU were performed in the non-urolithiasis group and correctly diagnosed 23 cases of renal or ureteral tumors, 4 cases of congenital disorder (2 duplications, 1 congenital renal agenesis due to VATER syndrome and 1 retrocaval ureter). Five of 34 patients with chronic inflammatory process of urinary tract or ureteral stricture were indistinct from malignancies according to the imaging of CT urography. CONCLUSIONS: CTU is good modality for demonstration of urinary tract disorders. It is better in showing radiolucent stones and non-opacified urinary system. CTU demonstrates more soft tissue information than IVU in the patients with urinary tract tumors. CTU may be an alternative modality for patients with deterioration of renal function or allergic history of contrast medium.

Diagnostic value of unenhanced computerized tomography urography in the evaluation of acute renal colic.

This study prospectively evaluated the diagnostic value of unenhanced computerized tomography (CT) urography in patients with acute renal colic. Fifty-nine patients with clinical manifestations of acute renal colic underwent unenhanced helical CT to evaluate urinary tract abnormalities. Reformatted three-dimensional CT urography was performed in all patients. The findings were correlated with ureteroscopy, surgical findings, histopathologic findings, and clinical course. CT urography detected urinary abnormalities in 57 of 59 patients with the clinical manifestation of acute renal colic, including 45 cases of urolithiasis, three urinary malignancies, one congenital abnormality, and eight ureteral strictures (due to chronic inflammation or fibrosis). CT urography showed negative findings in the urinary system in two patients, and after clinical follow-up, urinary abnormality was excluded in these patients. Incidental findings of extrarenal disease were noted in six patients (pulmonary abnormalities, n = 2; gallstones, n = 4). Only one patient with urolithiasis was misdiagnosed as having a renal tumor by CT urography. The sensitivity and specificity of CT urography in diagnosing urolithiasis was 97.8% (44/45) and 100% (14/14), respectively. Three-dimensional CT urography is a newly developed modality to evaluate anomalies of the urinary tract. The highly accurate diagnostic value of CT urography makes it a suitable alternative or substitutive modality in patients with acute flank pain.

Malignant renal epithelioid angiomyolipoma with aggressive behavior and distant metastasis.

Angiomyolipoma (AML) is a common renal tumor and mostly benign in entity. Malignant AML is extremely rare and most of them are found to be epithelioid AML histopathologically. We report the imaging features of a malignant epithelioid AML in a 58-year-old patient with liver and nodal metastases, and review the literatures. We have observed that AML of epithelioid subtype with tumoral necrosis may suggest the malignant change.