Contrast-enhanced US and contrast-enhanced CT for diagnosis of focal liver lesions in liver transplant recipients: A comparative study

Background and aims

Contrast-enhanced ultrasound (CEUS) is widely used in the diagnosis of complications after liver transplantation. This study compared the diagnostic efficacy of CEUS with that of contrast-enhanced computed tomography (CECT) for focal liver lesions in liver transplant recipients.

Methods

We retrospectively reviewed 115 liver transplant recipients who were diagnosed to have focal liver lesions at our hospital between June 2015 and June 2023. All patients were examined by CEUS and CECT and had a definitive pathological diagnosis. Based on the diagnostic outcomes, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of these imaging modalities in differentiating between benign and malignant lesions were calculated using a four-table method. Differences in diagnostic efficacy between CEUS and CECT with respect to pathological findings were compared using the chi-squared test and Fisher's exact test. The consistency of diagnosis between these modalities was assessed using the linear weighted kappa test.

Results

CEUS identified 79 malignant and 36 benign lesions, while CECT detected 81 malignant and 34 benign lesions. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of CEUS and CECT in diagnosis of focal lesions in transplanted livers were 95.7% vs 97.2%, 97.2% vs 96.1%, 97.9% vs 97.5%, 97.2% vs 98.6%, and 96.4% vs 97.1%, respectively. Both CEUS and CECT demonstrated comparable diagnostic efficacy (κ = 0.899). CEUS showed strong diagnostic consistency with pathological results (κ = 0.912) and was more effective than CECT in diagnosing focal normal liver tissue and fat infiltration (p < 0.05). Both methods were equally effective for diagnosis of focal inflammatory lesions, infarction, and hemangioma.

Conclusion

CEUS is as effective as CECT for diagnosis of benign and malignant lesions in transplanted livers but surpasses CECT in differentiating benign lesions, particularly focal normal liver tissue and fat infiltration.