Non-Invasive Differentiation of Liver Hemangiomas and Colorectal Metastases: The Role of Apparent Diffusion Coefficient in Reducing Unnecessary Liver Biopsies

Abstract

Diffusion-weighted imaging (DWI) and the calculation of the Apparent Diffusion Coefficient (ADC) provide valuable functional information at the molecular level, which can aid in distinguishing hepatic lesions. This study aims to assess the role of MRI DWI and ADC values in differentiating between hepatic hemangiomas and colorectal liver metastases (CRLMs), focusing on lesion size and potential to reduce reliance on liver biopsy. In this prospective observational study conducted from January 2019 to February 2020 at Hiwa Cancer Hospital, 61 patients with newly diagnosed colorectal cancer (CRC) and suspicious liver lesions underwent abdominal MRI. Lesions were characterized using DWI with two b-values (b=50 and b=800 sec/mm²), and ADC values were calculated for both hemangiomas and metastases. The histopathological diagnosis of CRLM was confirmed for all cases. The study excluded larger or necrotic lesions and focused on lesion size influencing ADC values and ratios. Statistical analysis was performed using SPSS version 25. Hemangiomas demonstrated significantly higher ADC values and ADC ratios than metastases, particularly in smaller lesions (≤21.5 mm), with a P<0.001. In lesions >21.5 mm, while ADC values were less pronounced, ADC ratios remained significantly higher for hemangiomas (P=0.02). ADC values in left lobe lesions were slightly higher than those in the right lobe, although this difference did not reach statistical significance.  MRI DWI with ADC measurement is valuable for differentiating hepatic hemangiomas from colorectal liver metastases, especially in smaller lesions. The significantly higher ADC values and ratios in hemangiomas can help avoid unnecessary biopsies and reduce the risk of metastasis seeding, which is particularly crucial in patients with resectable liver metastases.