Occlusion of transplant renal artery secondary to thrombus

Edematous hypoechoic kidney if total thrombosis

Absence of blood flow in main renal artery

Diffuse absence of parenchymal perfusion on color or power Doppler

Blunted low-resistance waveforms in ischemic areas from collateral flow

If involving accessory renal artery

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  Segmental wedge-shaped peripheral area of decreased color flow and altered echogenicity

Color, power, spectral Doppler US 1st-line imaging modality for complications of renal transplantation

Optimize color and spectral Doppler settings for slow flow

Transplant renal vein thrombosis

Acute rejection/acute on chronic rejection

Hyperacute rejection

Rare (< 1%)

Abrupt onset of oliguria, decreased function, pain and swelling of allograft

Poor prognosis; graft loss typical when single main artery thrombosed

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  Transplant nephrectomy

  
  
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  Thrombectomy or thrombolysis rarely successful unless diagnosis made early

Accessory or segmental arterial thrombosis → ischemia and subsequent atrophy

Severe acute rejection or tubular necrosis may cause propagating small vessel thrombosis resulting in infarction and mimicking transplant renal artery thrombosis

Urgent finding requiring prompt communication