Published online Jul 21, 2022. doi: 10.3748/wjg.v28.i27.3488
Peer-review started: December 17, 2021
First decision: January 27, 2022
Revised: February 10, 2022
Accepted: June 16, 2022
Article in press: June 16, 2022
Published online: July 21, 2022
Processing time: 212 Days and 17.4 Hours
Contrast-enhanced ultrasound (CEUS) is considered a secondary examination compared to computed tomography (CT) and magnetic resonance imaging (MRI) in the diagnosis of hepatocellular carcinoma (HCC), due to the risk of misdiagnosing intrahepatic cholangiocarcinoma (ICC). The introduction of CEUS Liver Imaging Reporting and Data System (CEUS LI-RADS) might overcome this limitation. Even though data from the literature seems promising, its reliability in real-life context has not been well-established yet.
To test the accuracy of CEUS LI-RADS for correctly diagnosing HCC and ICC in cirrhosis.
CEUS LI-RADS class was retrospectively assigned to 511 nodules identified in 269 patients suffering from liver cirrhosis. The diagnostic standard for all nodules was either biopsy (102 nodules) or CT/MRI (409 nodules). Common diagnostic accuracy indexes such as sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were assessed for the following associations: CEUS LR-5 and HCC; CEUS LR-4 and 5 merged class and HCC; CEUS LR-M and ICC; and CEUS LR-3 and malignancy. The frequency of malignant lesions in CEUS LR-3 subgroups with different CEUS patterns was also determined. Inter-rater agreement for CEUS LI-RADS class assignment and for major CEUS pattern identification was evaluated.
CEUS LR-5 predicted HCC with a 67.6% sensitivity, 97.7% specificity, and 99.3% PPV (P < 0.001). The merging of LR-4 and 5 offered an improved 93.9% sensitivity in HCC diagnosis with a 94.3% specificity and 98.8% PPV (P < 0.001). CEUS LR-M predicted ICC with a 91.3% sensitivity, 96.7% specificity, and 99.6% NPV (P < 0.001). CEUS LR-3 predominantly included benign lesions (only 28.8% of malignancies). In this class, the hypo-hypo pattern showed a much higher rate of malignant lesions (73.3%) than the iso-iso pattern (2.6%). Inter-rater agreement between internal raters for CEUS-LR class assignment was almost perfect (n = 511, k = 0.94, P < 0.001), while the agreement among raters from separate centres was substantial (n = 50, k = 0.67, P < 0.001). Agreement was stronger for arterial phase hyperenhancement (internal k = 0.86, P < 2.7 × 10-214; external k = 0.8, P < 0.001) than washout (internal k = 0.79, P < 1.6 × 10-202; external k = 0.71, P < 0.001).
CEUS LI-RADS is effective but can be improved by merging LR-4 and 5 to diagnose HCC and by splitting LR-3 into two subgroups to differentiate iso-iso nodules from other patterns.
Core Tip: This is a retrospective study to evaluate the accuracy of contrast-enhanced ultrasound Liver Imaging Reporting and Data System (CEUS LI-RADS) in correctly diagnosing hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) in patients with cirrhosis. CEUS LR-5 showed a 97.7% specificity for HCC with a low sensitivity (67.6%), while the CEUS LR-4 and 5 merged class showed a 93.9% sensitivity and 94.3% specificity for HCC. CEUS LR-M predicted ICC with a 91.3% sensitivity and 96.7% specificity. CEUS LR-3 predominantly included benign lesions (28.8% of malignancies) but was heterogeneous as the hypo-hypo pattern showed a higher rate of malignant lesions (73.3%) than the iso-iso pattern (2.6%).