Radiology, Vol 158, 647-648, Copyright © 1986 by Radiological Society of North America
Renal obstruction in patients with ileal loops: US evaluation
JJ Cronan, ES Amis, FH Scola and B Schepps
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.
