Is Contrast Enhanced Ultrasonography a useful tool in a beginner's hand? How much can a Computer Assisted Diagnosis prototype help in characterizing the malignancy of focal liver lesions?

Abstract

Contrast enhanced ultrasound (CEUS) improved the characterization of focal liver lesions (FLLs), but is an operatordependentmethod. The goal of this paper was to test a computer assisted diagnosis (CAD) prototype and to see its benefitin assisting a beginner in the evaluation of FLLs. Our cohort included 97 good quality CEUS videos[34% hepatocellular carcinomas (HCC), 12.3% hypervascular metastases (HiperM), 11.3% hypovascular metastases (HipoM),24.7% hemangiomas (HMG), 17.5% focal nodular hyperplasia (FNH)] that were used to develop a CAD prototype based onan algorithm that tested a binary decision based classifier. Two young medical doctors (1 year CEUS experience), two expertsand the CAD prototype, reevaluated 50 FLLs CEUS videos (diagnosis of benign vs. malignant) first blinded to clinical data,in order to evaluate the diagnostic gap beginner vs. expert. The CAD classifier managed a 75.2% overall (benign vs.malignant) correct classification rate. The overall classification rates for the evaluators, before and after clinical data were:first beginner-78%; 94%; second beginner-82%; 96%; first expert-94%; 100%; second expert-96%; 98%. For both beginners,the malignant vs. benign diagnosis significantly improved after knowing the clinical data (p=0.005; p=0,008). The expert wasbetter than the beginner (p=0.04) and better than the CAD (p=0.001). CAD in addition to the beginner can reach the expertdiagnosis. The most frequent lesions misdiagnosed at CEUS were FNH and HCC. The CAD prototype is a goodcomparing tool for a beginner operator that can be developed to assist the diagnosis. In order to increase the classification rate,the CAD system for FLL in CEUS must integrate the clinical data.