Isabel C. Yoder

Ultrasonic inaccuracies in diagnosing renal obstruction

Renal ultrasound is an excellent screening examination for suspected urinary tract obstruction. Its usefulness is based on the ability to detect hydronephrosis. However, it must be recognized that a significant number of conditions exist which can mimic or produce dilatation of the collecting system without urinary tract obstruction. Similarly, obstruction without hydronephrosis, although infrequent, exists. Situations causing either false positive or false negative renal sonograms are discussed. Renal sonography suggesting hydronephrosis should be followed with additional diagnostic studies to confirm or exclude obstruction. Similar persistence should be used when obstruction is strongly suggested clinically, and ultrasound fails to demonstrate hydronephrosis.

Spermatic Cord Sarcomas: Sonographic and CT Features

Five patients with sarcomas of the spermatic cord were imaged with sonography and/or computed tomography (CT). The former modality is most helpful in demonstrating the extratesticular origin of the mass and evaluating its scrotal extension for local staging. CT is necessary for pelvic staging and searching for distant metastasis. The fat in liposarcomas was easily identified by CT, although it was not echogenic on sonography. Sonography should be the primary imaging modality for scrotal or inguinal masses. If a neoplasm is found, CT should be used for staging, prior to definitive surgical treatment.

Comparison of Excretory phase, helical computed tomography with intravenous urography in patients with painless haematuria

AIM To compare excretory phase, helical computed tomography (CT) with intravenous (IV) urography for evaluation of the urinary tract in patients with painless haematuria. MATERIALS AND METHODS Ninety-one out-patients had IV urography followed by helical CT limited to the urinary tract. Both IV urograms and CT images were evaluated for abnormalities of the urinary tract in a blinded, prospective manner. The clinical significance of abnormalities was scored subjectively and receiver operator characteristic curve analysis was performed. RESULTS In 69 of 91 patients (76%), no cause of haematuria was identified. In 22 of 91 patients (24%), the cause of haematuria was identified as follows: transitional cell cancer of the bladder (n=15), urinary tract stones (n=3), cystitis (n=2), haemorrhagic pyelitis (n=1) and benign ureteral stricture (n=1). With IV urography, there were 15 true-positive, seven false-negative and three false-positive interpretations. With CT, there were 18 true-positive, four false-negative and two false-positive interpretations. There was no significant difference between IV and CT urography for the significance of the positive interpretations (n=0.47). CONCLUSION Excretory phase CT urography was comparable with IV urography for evaluation of the urinary tract in patients with painless haematuria. However, the study population did not include any upper tract cancers.

Percutaneous occlusion of ureteral leaks and fistulae using nondetachable balloons

High-output ureteral fistulae were managed percutaneously in 3 patients with pelvic malignancies. Urine flow was diverted by combining percutaneous nephrostomy catheter drainage with transrenal balloon occlusion of the affected ureter proximal to the site of extravasation. This technique can be used either alone as the definitive method of treatment or as the initial procedure to preserve renal function and reverse the inflammatory reaction prior to subsequent surgical repair; its primary application is in patients in whom antegrade or retrograde ureteral stenting is not feasible or possible.

Percutaneous internal ureteral stent placement: review of technical issues and solutions in 50 consecutive cases.

Fifty consecutive percutaneous ureteral stent placements in 40 patients over 2 1/2 years were reviewed. Thirty-seven of 50 cases were performed following failed retrograde stenting. Antegrade stenting failed in 2/37 (5%) cases of malignant obstruction, and 4/13 (31%) cases of benign ureteral disease. Causes of failure and common technical problems included poor angulation of the percutaneous track, tortuous dilated ureters, tight obstructions, wedging of stent assembly components due to high resistance, and difficulty in positioning of the proximal pigtail. Helpful technical modifications included mid-pole rather than lower pole calyceal access, urinary decompression prior to stenting, and the routine use of a peel-away sheath (success rate 23/24 placements with sheath vs 21/26 without sheath). Stent patency rates were 95% at 3 months and 54% at 6 months. With attention to technique and appropriate modifications, success rate of percutaneous stenting remained high in this series despite the large number of cases referred after retrograde stenting had failed.

Ileal loop stenosis: a late complication of urinary diversion.

Stenosis of the ileal conduit was a late complication in 12 patients (10 adults) who underwent urinary diversion by this means at our hospital. The duration of the ileal loop at diagnosis ranged from 4 to 14 years, averaging 9 years. Loop stenosis was generally without symptoms and was suggested only by routine excretory urography, while loopography confirmed the diagnosis. The etiology of the condition is not clear. A variety of possible factors is considered, including microvascular ischemia, urine-borne toxic material, infectious and allergic stimuli and an immunologic defect. The pathogenesis of the condition appears to be based upon a chronic inflammatory reaction, with progressive fibrosis in the mucosa and submucosa of the ileal segment.

Renal cysts: Curios and caveats

Interesting, unusual, and confusing renal cysts from a group of 200 cysts punctured percutaneously during the past decade are presented.Some cases illustrate pressure phenomena in cysts adjacent to each other or causing calyceal obstruction. Also reported are cyst wall findings, unusual cyst configurations, infection in pre-existing cysts, examples of cysts simulating renal cell carcinoma, and renal cell carcinoma presenting as cysts.In unusual cases, percutaneous needle puncture remains the procedure of choice for establishing the diagnosis of benign simple cyst versus malignancy or infection, or for determining the relationship of a cyst with the collecting system or with other cysts. Cyst puncture may also result in iatrogenic changes.

Diagnostic Imaging in the Evaluation of Renal Lymphoma

Renal lymphoma usually is a manifestation of disseminated disease and often is asymptomatic. Occasionally, the kidney(s) may be the major or only demonstrable site of disease, which may then present with a variety of urologic symptoms. The imaging studies should be tailored according to the presenting symptoms and prior history. Currently CT with intravenous contrast material enhancement is the study of choice for both the evaluation of renal involvement as well as staging of the disease. When necessary, CT or sonography may be used to guide percutaneous needle biopsy of suspicious masses. The role of the various imaging techniques, including MR and positron emission tomography, in the evaluation of renal lymphoma is discussed.

Peripelvic cysts: an impostor of sonographic hydronephrosis.

Static and real‐time ultrasound examinations have proved clinically useful in the evaluation of renal obstruction. False‐negative findings are rare. False‐positive findings have been reported as being due to slightly dilated, nonobstructed urinary systems causing the ultrasonographic appearance of mild (grade I) hydronephrosis. The authors describe the ultrasonographic appearance of 16 false‐positive cases that had suggested moderate (grade II) to severe (grade III) hydronephrosis in collecting systems subsequently shown to be completely unobstructed. This appearance was caused by peripelvic cysts. These cases emphasize the screening role of ultrasound and the need to employ additional diagnostic modalities to verify the presence of hydronephrosis and renal obstruction.

Primary retroperitoneal neoplasms: How close can we come in making the correct diagnosis

The primary retroperitoneal tumors form a rare and diverse group of neoplasms, the origin of which is independent of the various retroperitoneal organs and unrelated to systemic diseases, such as lymphomas, lymphadenopathy, or metastases. Radiologic investigation, mainly cross-sectional imaging and, to a lesser extent, angiography is essential in the diagnosis and management of these tumors. The radiologist often is challenged to identify the origin and specific tissue composition of the imaged neoplasms. When the radiologic findings are combined with patient information and clinical data, the correct diagnosis may be made in many cases. Imaging-guided percutaneous needle biopsy further enhances the diagnostic yield of the various imaging modalities by establishing the diagnosis without the need for exploration.