Diagnostic Ultrasound - Abdomen and Pelvis

Allograft Hydronephrosis
Diagnoses: Kidney Transplant
TERMINOLOGY
• Dilated renal pelvis and calyces, usually secondary to
obstruction
IMAGING
• Over 90% at ureterovesical anastomosis and distal 1/3 of
ureter
• Low-level echoes within lumen suggest pus (pyonephrosis)
or blood (hemonephrosis)
• Highly echogenic shadowing intraluminal structures
represent stones
• Highly echogenic, weakly shadowing masses, suggest
fungal balls
• Ultrasound is sensitive and specific for hydronephrosis
• Ultrasound may be limited for site of obstruction and
cannot providefunctional information
• Antegrade nephrostogram is gold standard in
differentiating fixed from transient obstruction and for
localizing site obstruction
KEY FACTS
○ Usually combined with ultrasound guidance to access
collecting system
• MR/MRU comprehensive high-resolution evaluation of
entire urinary tract, including distal to obstruction
TOP DIFFERENTIAL DIAGNOSES
• Nonobstructive dilatation
• Pyo- or hemonephrosis
• Ureteral calculi
• Urothelial thickening
• Transitional cell carcinoma (TCC)
• Renal sinus cysts
• Prominent hilar vessels
DIAGNOSTIC CHECKLIST
• Ultrasound is first-line imaging modality for renal transplant
dysfunction in immediate postoperative period or for
follow-up
(Left) Longitudinal ultrasound
shows mild to moderate
hydronephrosis in a renal
transplant. The ureter ſt is
dilated secondary to
obstruction by a fluid
collection st, which wrapped
around the ureter. (Right)
Longitudinal ultrasound shows
mild to moderate
hydronephrosis secondary
to a shadowing calculus ſt in
the transplant ureter.
(Left) Transverse ultrasound
shows a debris level ſt within
a dilated renal pelvis . This
was secondary to infection in a
chronically dilated collecting
system. (Right) Longitudinal
ultrasound shows a dilated
renal pelvis and calyces, which
are filled with avascular
hypoechoic clot ſt. The
hemonephrosis was secondary
to a renal transplant biopsy.
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