Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Three The Abd omen 387
A
B
Fig. 3-166 Transverse (A to C) and
longitudinal (D) sonograms of the
left kidney of a 4-year-old male
Great Dane with a history of hematuria
of 4 months duration. The
renal architecture is markedly distorted
with a large mass arising from
the dorsal surface of the kidney
(arrows). There is poor corticomedullary
distinction within the
more normal-appearing portions of
the kidney. This mass could represent
a tumor or granuloma. A renal
biopsy was performed, and
Escherichia coli pyelonephritis with
renal abscess was diagnosed.
Diagnosis: Pyelonephritis with
abscess.
C
D
Fig. 3-167 Transverse sonograms of
the left kidney of a 9-year-old spayed
female Schnauzer with a history of
urolithiasis of 3 months duration.
There is mild dilation of the renal
pelvis (solid arrows). This may be
secondary to obstruction or infection.
There is a hyperechoic zone in
the renal pelvis (open arrows). This is
indicative of pyelonephritis.
Diagnosis: Pyelonephritis.
Diffuse uniform hyperechoic patterns may occur in association with lymphosarcoma,
FIP, CIN, chronic pyelonephritis, chronic glomerulonephritis, renal dysplasia, renal mineralization,
and with hemoglobin or hemosiderin deposits within the kidney (Figs. 3-165 and
3-168 to 3-170).
A diffuse uniform anechoic pattern will occur secondary to hydronephrosis. A diffuse
heteroechoic pattern of hyperechoic and anechoic (cavitating) areas may be seen with
polycystic kidney disease (Figs. 3-171 and 3-172).
Nephrocalcinosis may produce a diffusely hyperechoic kidney but it also can produce
a hyperechoic band at the corticomedullary junction (Fig. 3-173). 492,493 This hyperechoic
band has been referred to as the medullary rim sign and has been reported in association
with acute tubular necrosis, pyogranulomatous vasculitis, CIN, and hypercalcemia (Figs.
3-174 and 3-175). 493 However, this rim sign also has been reported in patients without
apparent disease. 494 Therefore its utility is, in our opinion, questionable and it may merely
indicate some nonspecific medullary degeneration or mineralization. Acoustic shadowing
may or may not be present. Chronic renal failure also may produce a hyperechoic renal
medulla. Ethylene glycol poisoning produces a similar hyperechoic medulla with a surrounding
hypoechoic area. This has been termed the halo sign and is associated with a