The Impact of Diffuse Liver Disease on Liver Lesion Detection and Characterization.

Diffuse liver diseases, including steatosis, cirrhosis, and fibrosis, significantly alter hepatic architecture, and can obscure, mimic, or alter the imaging features of focal liver lesions and reduce the diagnostic accuracy of specific imaging modalities. This review outlines the key imaging pitfalls created by diffuse liver disease and offers practical, evidence-based strategies to overcome them. We describe several key imaging pitfalls in interpreting liver lesions in diffuse liver disease, including the atypical appearance of focal lesions on ultrasound and CT due to altered background parenchyma; the phenomenon of "vanishing washout" of hepatocellular carcinoma on CT in steatotic livers; and the significant risk of underestimating metastatic disease burden or missing occult lesions. For each pitfall, we discuss the strengths and weaknesses of various imaging modalities and suggest problem-solving strategies, such as guidance on selecting the most appropriate next-line imaging modality for lesion characterization. We highlight the roles of contrast-enhanced ultrasound and MRI in resolving diagnostic uncertainty when initial ultrasound or CT imaging is atypical or equivocal. A comprehensive understanding of how diffuse liver disease affects the imaging of both benign and malignant lesions is important for accurate diagnosis. Recognizing these pitfalls allows a tailored, multimodality imaging approach that optimizes the detection and characterization of focal liver lesions, ultimately guiding clinical management and improving patient care.