Purpose: To introduce and validate a novel perfusion index derived from contrast-enhanced ultrasound (CEUS) for assessing graft viability after liver transplantation.

Methods: Thirty post-transplant patients were prospectively evaluated using CEUS within 72 hours of surgery. The quantitative perfusion index (QPI) was compared with Doppler ultrasound and clinical outcomes.

Results: Patients with normal graft function exhibited significantly higher QPI (mean 2.45 ± 0.5) than those with perfusion compromise (1.12 ± 0.3; p < 0.001). QPI correlated strongly with hepatic artery flow (r = 0.84).

Conclusion: CEUS-derived QPI provides a reproducible and sensitive biomarker for early detection of vascular compromise in transplanted livers.

Keywords: Contrast-enhanced ultrasound, liver transplant, perfusion, quantitative imaging