Renal obstruction in patients with ileal loops: US evaluation

Ultrasound (US) is often employed as a screening test for hydronephrosis in the nondiverted kidney and has been used recently to evaluate the diverted kidney, specifically ileal loops, for obstruction. The utility of US in evaluating obstruction in patients with ileal loops has apparently not been previously explored. During a 2-year period, 87 kidneys drained by an ileal loop diversion were examined with US because of clinical indications of possible renal obstruction. In 33 kidneys, no hydronephrosis was seen on sonograms, and no obstruction was later proved; in 51 kidneys, shown by US to be hydronephrotic, only 19 (37%) were obstructed. Three left kidneys were not visualized with US. The percentage of hydronephrotic kidneys subsequently shown to be obstructed increased rapidly as the US appearance progressed from grade 1 (20%) to grade 3 (80%). In this series, US had a 100% sensitivity and a 50% specificity in evaluating patients with ileal loops for renal obstruction. Thus, for the adult patient, a direct contrast evaluation of the collecting system is suggested; for the pediatric patient, initial use of US is justified as a means to avoid radiation exposure.     

Obstruction of the upper-pole moiety in renal duplication in adults: CT evaluation

Delineation of the presence and anatomy of an obstructed, nonfunctioning upper-pole duplex system often requires multiple imaging techniques. Computed tomography (CT) was used to evaluate duplex systems in five adult patients. Independent of renal function, CT allowed assessment of the presence of a duplex system, determination of whether the system was obstructed, assessment of the quantity of residual parenchyma in the upper-pole system, determination of whether the ectopic ureter was intravesical or extravesical, and assessment of the retroperitoneum to look for unusual causes of upper-pole ureteral obstruction.     

Vertebral hemangiomas: radiologic evaluation

Radiologic studies of 57 solitary vertebral hemangiomas (VHs) were reviewed to find radiographic and computed tomographic (CT) criteria by which to distinguish asymptomatic lesions from those compressing the spinal cord. Six features were seen significantly more often in those compressing the cord: location between T-3 and T-9, involvement of the entire vertebral body, extension to the neural arch, an expanded cortex with indistinct margins, an irregular honeycomb pattern, and soft-tissue mass. Contrast material-enhanced CT scans and selective spinal angiograms demonstrated extension into the spinal canal. In patients with a VH and back pain of uncertain origin, the presence of three or more of these signs may indicate a potentially symptomatic VH. In such patients, spinal angiography and, in some cases, embolization, are indicated.     

Safety of 4-T MR imaging: study of effects on developing frog embryos

Fertilized eggs of Rana pipiens (leopard frogs) were exposed to 0.15- or 4.5-T magnetic resonance (MR) imaging and were compared with unexposed fertilized eggs with respect to the percentage of embryos cleaving and percentage of tail buds forming normally. Similarly exposed or unexposed sperm were used to fertilize unexposed eggs, and the same parameters were observed. There was no evidence that MR imaging exposure at 0.15 or 4.5 T had any effect on cleaving embryos or tail bud formation. Since embryogenesis in amphibians is very sensitive to foreign insult, the authors conclude that exposure to a magnetic field of up to 4.5 T has no adverse effect on early development.