Contrast-enhanced ultrasound for the evaluation of hepatic artery stenosis after liver transplantation: potential role in changing the clinical algorithm.

Hepatic artery stenosis (HAS) is a common complication in liver transplant patients. Conventional angiography remains the gold standard for diagnosis. Recently, contrast-enhanced ultrasound (CEUS) has begun providing real-time angiographic-like images of vessels and allowing the accurate diagnosis of arterial diseases such as hepatic artery thrombosis. The purpose of this study was to evaluate the efficacy of CEUS in depicting HAS after liver transplantation. Forty-seven liver transplant recipients underwent CEUS examinations with the intravenous injection of microbubble contrast agents. The reference standard was conventional angiography for 15 patients and computed tomographic angiography for 32 patients. The presence, degree, location, and type of HAS were evaluated. For the detection of HAS by CEUS, the following was found: an accuracy of 91.5% (43/47), a sensitivity of 92.3% (36/39), a specificity of 87.5% (7/8), a positive predictive value of 97.3% (36/37), and a negative predictive value of 70% (7/10). CEUS corrected false-positive findings on color Doppler ultrasound in 7 of 47 cases (14.9%). The accuracy of CEUS in identifying the location and type of HAS was 92.3% (36/39) and 84.6% (33/39), respectively. CEUS is a useful noninvasive technique for the detection of HAS in liver transplant patients because it provides comprehensive information, including the presence, location, degree, and type. A positive CEUS finding suggests angiography as the next step rather than a computed tomography scan and may thereby alter the clinical imaging algorithm.