Indeterminate solid hepatic lesions identified on non-diagnostic contrast-enhanced computed tomography: assessment of the additional diagnostic value of contrast-enhanced ultrasound in the non-cirrhotic liver.

Objective: To assess the additional diagnostic value of contrast-enhanced ultrasound (CEUS) in the characterization of indeterminate solid hepatic lesions identified on non-diagnostic contrast-enhanced computed tomography (CT).

Methods: Fifty-five solid hepatic lesions (1-4 cm in diameter) in 46 non-cirrhotic patients (26 female, 20 male; age±SD, 55±10 years) underwent CEUS after being detected on contrast-enhanced CT which was considered as non-diagnostic after on-site analysis. Two blinded independent readers assessed CT and CEUS scans and were asked to classify retrospectively each lesion as a malignant or benign based on reference diagnostic criteria for the different hepatic lesion histotypes. Diagnostic accuracy and confidence (area--Az--under ROC curve) were assessed by using gadobenate dimeglumine-enhanced magnetic resonance (MR) imaging (n=30 lesions), histology (n=7 lesions), or US follow-up (n=18 lesions) as the reference standards.

Results: Final diagnoses included 29 hemangiomas, 3 focal nodular hyperplasias, 1 hepatocellular adenoma, and 22 metastases. The additional review of CEUS after CT images improved significantly (P<.05) the diagnostic accuracy (before vs after CEUS review=49% [20/55] vs 89% [49/55]--reader 1 and 43% [24/55] vs 92% [51/55]--reader 2) and confidence (Az, 95% Confidence Intervals before vs after CEUS review=.773 [.652-.895] vs .997 [.987-1]--reader 1 and .831 [.724-.938] vs .998 [.992-1]--reader 2).

Conclusions: CEUS improved the characterization of indeterminate solid hepatic lesions identified on non-diagnostic contrast-enhanced CT by identifying some specific contrast enhancement patterns.