FIGURE 6. Chronic effects of obstruction on renal function and anatomy shown by 3 studies from same patient. On 9/14/95, right kidney was totally obstructed for several days, resulting in hydronephrosis and decreased flow and function. Left kidney had good function and drainage. Patient did not accept decompression. On 3/29/96, right kidney was still totally obstructed and barely functioning, whereas left kidney was acutely and completely obstructed. Patient was anuric. Bilateral decompression followed this study. On 10/7/96, patient had new left colic from stone, which induced left partial distal obstruction; left kidney had recovered much of its function since 3/29/96 because of decompression soon after obstruction. Right kidney had undergone atrophy because of persistent obstruction from 9/14/95 until 3/29/96, but drainage was normal. Studies were obtained after administration of 10 mCi MAG₃ and 40 mg furosemide. Selected pictures, from left to right, show flow study; images at 2 min, 10 min, and 30 min; and renograms. FL = first-pass flow (3-s image).