Sonographic diagnosis of hydronephrosis in patients with spinal cord injury: Influence of bladder fullness

Objective: To investigate and compare the diagnostic accuracy of prevoid an d postvoid renal sonography in detecting hydronephrosis in patients with sp inal cord injury. Study Design: A prospective, blind comparison of renal sonography and excre tory urography in 67 spinal cord injury patients who underwent periodic uro logic examinations. Renal sonography was performed twice, once when the pat ient's bladder was physiologically full (prevoid) and again when it was jus t emptied (postvoid). Results: Of 140 kidneys, 24 from 16 patients were found to have hydronephro sis by excretory urography; 116 kidneys had normal urogram findings. Prevoi d sonography missed the diagnosis of hydronephrosis in one kidney and showe d hydronephrosis in 18 kidneys that had normal results on excretory urograp hy (sensitivity, 95.8%; specificity, 84.5%; negative predictive value, 99.0 %). The postvoid sonograms did not detect hydronephrosis in four kidneys an d showed hydronephrosis in six kidneys that had normal results on excretory urography (sensitivity, 83.3%; specificity, 94.8%; negative predictive val ue, 96.5%). Compared to excretory urography, renal sonography detected eigh t more upper urinary tract abnormalities, which were confirmed by cystogram s or radioisotopic renograms. Conclusion: Performing renal sonography while the bladder is full can incre ase the sensitivity in detecting hydronephrosis in asymptomatic spinal cord injured patients. (C) 1998 by the American Congress of Rehabilitation Medi cine and the American Academy of Physical Medicine and Rehabilitation.