Multiparametric ultrasound for non-invasive evaluation of kidney graft function

Renal transplant (RT) remains the optimal treatment for end-stage renal disease and early complications might be detected in the postoperative period to improve long-term outcomes. To this regard, contrast enhanced ultrasound (CEUS) could be utilized to evaluate RT functional recovery and potentially detect acute rejection (AR) and/or renal ischemia signs.

Observational study of 107 consecutive patients waitlisted for RT. Participants underwent conventional ultrasound (CUS) and color-doppler-ultrasound (CDUS) to evaluate resistive index of segmental and interlobar arteries and quantitative CEUS techniques recording the following perfusion parameters: peak intensity (PI-c), rising time (RT-c), area under (AUC-c) the time intensity curve (TIC), time to peak (TTP-c) and mean transit time (MTT-c).

CEUS parameters sensibility and specificity to predict AR in the early post-operative period resulted in: 90% and 69% for PI-c, 95% and 64% for RT-c, 85% and 65% for AUC-c. The overall diagnostic performance of these three CEUS parameters in comparison to the same in CUS and CDUS resulted in a sensitivity and specificity of 95% and 49%, versus 85% and 46%, respectively, therefore CEUS examination with the analysis of PI-c, RT-c and AUC-c values increases the diagnostic sensitivity in predicting AR by approximately 15-20% compared to CDUS and by 30-40% compared to CUS.

CEUS could be routinely included in RT follow-up, as it shows to be a non-invasive helpful diagnostic tool for early detection of renal graft complications, selecting patients eventually in need of further confirmation.