Diagnostic Ultrasound - Abdomen and Pelvis

Renal Transplant Rejection
Diagnoses: Kidney Transplant
IMAGING
• No specific imaging characteristics
• Ultrasound-guided renal biopsy is gold standard
• Acute rejection (AR): Nonspecific allograft edema,
urothelial thickening; elevated resistive index may be
present but is not specific
• Chronic rejection (CR): Cortical atrophy, increased
echogenicity, calcification
• Color perfusion may be decreased in AR or CR
• Tc-99m MAG3 renogram may show decreased perfusion
and uptake but is nonspecific
TOP DIFFERENTIAL DIAGNOSES
• Acute tubular necrosis/delayed graft function
• Infection
• Calcineurin inhibitor toxicity
KEY FACTS
PATHOLOGY
• Adequate biopsy sample requires at least 10 glomeruli and
2 arteries with 2 separate cores through cortex
• Acute cellular rejection: T lymphocyte interstitial infiltration,
tubulitis, and arteritis
• Acute humoral antibody-mediated rejection: transmural
arteritis and fibrinoid necrosis
• CR: Vascular sclerosis, fibrosis, and tubular atrophy
CLINICAL ISSUES
• Elevation of creatinine
• Oliguria or anuria
• Fever, graft tenderness, or swelling
• 14% in first 3-6 months
• Acute cellular rejection most common, after 1st
postoperative week
(Left) Longitudinal color
Doppler ultrasound of a renal
transplant with oliguria
secondary to acute rejection
shows global decrease in color
flow. The renal pelvic
urothelium is thick ſt. (Right)
Longitudinal pulsed Doppler
ultrasound of the same renal
transplant shows a highresistance
arterial waveform
with absence of flow in
diastole ſt.
(Left) Longitudinal ultrasound
of a living related renal
transplant with biopsy-proven
moderate acute cell-mediated
rejection is shown. Other than
urothelial thickening ſt, the
kidney appears normal. (Right)
Longitudinal pulsed Doppler
ultrasound of the same
patient shows normal diastolic
flow and a resistive index
within normal limits at 0.69.
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