Complementary Role of CEUS and CT/MR LI-RADS for Diagnosis of Recurrent HCC

The diagnostic performance of LI-RADS on CEUS and CT/MRI for characterizing primary HCC has been widely evaluated, but their diagnostic performance on recurrent HCC has not yet. Previous studies that used the same diagnostic criteria for the diagnosis of recurrent HCC proved inadequate, as only a subset (approximately 55-80%) of recurrent HCC cases exhibited the typical imaging features observed in primary HCC on contrast-enhanced CT or MRI. Consequently, this study embarked on an investigation to establish the optimal diagnostic algorithms for recurrent HCC using CEUS, CT, and MRI, and compared the diagnostic performance of CEUS and CT/MRI LI-RADS for recurrent HCC. The results indicated that LR-4/5/M criteria were optimal for CEUS and CT, while LR-5/M criteria were suitable for MRI. CEUS demonstrated better diagnostic performance than CT, while was comparable to MRI. Further, this study analyzed factors affecting the accurate characterization and detection of recurrent HCC on CEUS. Depth and visualization score C were found to hinder accurate characterization, and lesions in US blind spots with visualization score C posed challenges for detection.Purpose: We retrospectively compared the diagnostic performance of contrast-enhanced ultrasonography (CEUS) and contrast-enhanced computer tomography-magnetic resonance imaging (CT/MRI) for recurrent hepatocellular carcinoma (HCC) after curative treatment. Materials and methods: After curative treatment with 421 ultrasound (US) detected lesions, 303 HCC patients underwent both CEUS and CT/MRI. Each lesion was assigned a Liver Imaging Reporting and Data System (LI-RADS) category according to CEUS and CT/MRI LI-RADS. Receiver-operating characteristic (ROC) curves were computed to determine the optimal diagnosis algorithms for CEUS, CT and MRI. The diagnostic accuracy, sensitivity, specificity, and area under the curve (AUC) were compared between CEUS and CT/MRI. Results: Among the 421 lesions, 218 were diagnosed as recurrent HCC, whereas 203 lesions were diagnosed as benign. In recurrent HCC, CEUS detected more arterial hyperenhancement (APHE) and washout than CT and more APHE than MRI. CEUS yielded better diagnostic performance than CT (AUC: 0.981 vs. 0.958) (p = 0.024) comparable diagnostic performance to MRI (AUC: 0.952 vs. 0.933) (p > 0.05) when using their optimal diagnostic criteria. CEUS missed 12 recurrent HCCs, CT missed one, and MRI missed none. The detection rate of recurrent HCC on CEUS (94.8%, 218/230) was lower than that on CT/MRI (99.6%, 259/260) (p = 0.001). Lesions located on the US blind spots and visualization score C would hinder the ability of CEUS to detect recurrent HCC. Conclusion: CEUS demonstrated excellent diagnostic performance but an inferior detection rate for recurrent HCC. CEUS and CT/MRI played a complementary role in the detection and characterization of recurrent HCC.