Stephanie R. Wilson

Objectives Following positive surveillance ultrasound (US), magnetic resonance imaging (MRI) is recommended for further characterization. We propose contrast‐enhanced ultrasound (CEUS) shows equivalent efficacy. Methods This prospective institutional review board approved study recruited 195 consecutive at‐risk patients with a positive surveillance US. All had CEUS and MRI. Biopsy (n = 44) and follow‐up are gold standard. MRI and CEUS results are classified according to liver imaging reporting and data system (LI‐RADS) and patient outcome. Results As an US‐based modality, CEUS is superior in confirming findings from surveillance US, correlation in 189/195 (97%) on CEUS compared to 153/195 (79%) on MRI. Within these negative MRI examinations, there are 2 hepatocellular carcinoma (HCC) and 1 cholangiocarcinoma (iCCA) diagnosed on CEUS and proven by biopsy. From 195 patients, there are 71 malignant diagnoses from all sources, including 58 LR‐5 (45 on MRI and 54 on CEUS) and 13 others, including HCC outside of LR‐5 category, and LR‐M with biopsy proven iCCA (3 on MRI and 6 on CEUS). CEUS and MRI show concordant results in the majority of patients (146/195, 75%), including 57/146 malignant and 89/146 benign diagnoses. There are 41/57 concordant LR‐5 and 6/57 concordant LR‐M. When CEUS and MRI are discordant, CEUS upgraded 20 (10 biopsy‐proven) from MRI LR‐3/4 to CEUS LR‐5 or LR‐M by showing washout (WO) that MRI failed to show. Additionally, CEUS characterized time and intensity of WO and diagnosed 13/20 LR‐5 by showing late and weak WO and 7 LR‐M by showing fast and marked WO. CEUS is 81% sensitive and 92% specific in diagnosing malignancy. MRI is 64% sensitive and 93% specific. Conclusions CEUS performance is at least equivalent if not superior to MRI for initial evaluation of lesions from surveillance US.