This document contains images and captions describing different pathologies that can result in a small, smooth kidney appearance on imaging, including renal ischemia due to hypertension which diminishes kidney size, renal infarction from acute renal artery occlusion shown as a thin renal cortex, and radiation nephritis where radiation therapy caused significant shrinking of the left kidney over 5 years. It also describes congenital renal hypoplasia where the small left kidney is a miniature version but maintains normal function.

1. 2Unilateral Small, Smooth Kidney

2. CLINICAL IMAGAGING
AN ATLAS OF DIFFERENTIAL DAIGNOSIS
EISENBERG
DR. Muhammad Bin Zulfiqar
PGR-FCPS III SIMS/SHL

3. • Fig GU 2-1 Renal ischemia associated with
hypertension. Diminished size of the right
kidney (A) due to renal artery stenosis (B)
(arrow).

4. • Fig GU 2-2 Renal infarction due to acute renal
artery occlusion. (A) An initial nephrotomogram
demonstrates a thin cortical rim surrounding the
right kidney (arrows), reflecting viable renal
cortex perfused by perforating collateral vessels
from the renal capsule. (B) Four months later, a
repeat nephrotomogram shows a marked
decrease in the size of the atrophic right kidney
(arrowheads).1

5. • Fig GU 2-3 Radiation nephritis. Excretory urogram 5 years after
radiation therapy for abdominal lymphoma shows that the left
kidney has shrunk markedly. Delayed film showed no contrast
material in the collecting system. Although a large left paraspinous
mass deviates the axis of the left kidney, ultrasound revealed no
obstruction; the intensity of the nephrogram excludes long-standing
obstructive atrophy.2

6. • Fig GU 2-4 Congenital hypoplasia. The small
left kidney, a miniature replica of a normal
kidney, has good function and a normal
relation between the amount of parenchyma
and the size of the collecting system. Note the
compensatory hypertrophy of the right kidney.