Schwenger V et al. (2006) Real-time contrast-enhanced sonography of renal transplant recipients predicts chronic allograft nephropathy. Am J Transplant 6: 609–615

Vascular remodeling in renal transplants can impair renal blood flow and lead to graft failure. Color Doppler ultrasonography (CDU) can be used to assess renal perfusion in large arteries; however, real-time contrast-enhanced sonography (RTCES)—a technique that measures microvascular perfusion using gas-filled microbubbles—might enable more detailed assessment of renal blood flow. Schwenger et al. compared the efficacy of RTCES with that of CDU in determining blood flow in the graft for the detection of chronic allograft nephropathy.

Renal transplant patients (n = 26) were prospectively studied for a median of 30.5 months (range 3–274 months) after transplantation. RTCES renal blood flow estimates, but not CDU estimates, were significantly correlated with serum creatinine levels (P = 0.0004) and glomerular filtration rates (P = 0.007). Compared with CDU estimates, RTCES estimates had higher sensitivity (91% vs 82%; P <0.05), specificity (82% vs 64%; P <0.05) and accuracy (85% vs 73%; P <0.05) for detecting biopsy-confirmed chronic allograft nephropathy (n = 11).

The superior diagnostic power of RTCES compared with CDU might facilitate earlier detection of the changes in renal blood flow that are indicative of the onset of transplant vasculopathy, thereby permitting more timely initiation of therapeutic interventions.