Background: The aim of this study was to assess the disturbances in perfusion of transplanted kidneys (KTx) following an acute occlusion of 1 of the supernumerary renal arteries (SRA). We compared the differences in echogenicity and the size of ischemic areas between routine B mode ultrasonography with Doppler evaluation (US-CD) and contrast-enhanced ultrasound examination (CE-US).
Material/Methods: We present 4 KTx patients in whom we observed an occlusion of the SRA. After the initial diagnosis of occlusion of SRA in routine B mode with US-CD, the CE-US examination following intravenous contrast administration was performed. The disturbances of tissue perfusion in regions of interest, the level of signal intensity, and the size of the infarct were analyzed.
Results: The renal parenchyma in the routine B mode was characterized by low echogenicity. After the contrast medium administration, we observed increased echogenicity (–53.75±5.3 dB vs. –28.75±3.8 dB, p<0.001). The echogenicity between the focus of the infarct and normal parenchyma in the routine B mode and US-CD was small, but the difference was larger for analogous areas in the CE-US (the mean signal intensity: –2.75±1.5 dB in the B mode/US-CD vs. –24.25±3.9 dB in CE-US, p<0.001). The size of the ischemic areas in the B mode and Doppler examinations were underestimated due to poor separation of the ischemic foci, and were much better visualized in the CE-US (–25.5±7.3 mm vs. –38.5±9.7mm, p<0.001).
Conclusions: CE-US may enable a precise evaluation of a graft’s ischemic foci due to occlusion of SRA in the early post-transplant period.

Keywords: kidney graft perfusion, ischemic foci, contrast enhanced ultrasound