The Role of Diffusion-Weighted MRI in Correlation with Contrast-Enhanced MRI and Histopathology in the Evaluation of Focal Liver Lesions.

Abstract

Accurate diagnosis of focal liver lesions is of utmost importance for theinitiation ofappropriate treatment. This study aims to assess the effectiveness of diffusion-weighted imaging (DWI) in diagnosing focal liver lesions, specifically focusing on differentiating between benign and malignant lesions, distinguishing metastases from primary liver tumors, and identifying various types of both benign and malignant lesions.. The study design is that of a prospective observational study done on 28 cases withfocal liver lesions detected on ultrasound. DWI was done followed by contrast-enhanced MRI (CE-MRI). Identification of the lesion on DWI and apparent diffusion coefficient (ADC) map was madeby using the CE-MRI images as a guide. The signal intensity of the lesion on DWI is determined as either diffusion restriction or no restriction. ADC measurementswere made quantitatively over various regions of interest (ROIs) of the focal liver lesion. All the lesions were confirmed by histopathological examination (HPE) except few benign lesions like simple cysts and few hemangiomas, which were followed up by ultrasonography after six months. Our study included 28 patients with 44 focal liver lesions. Out of 28 patients in this study group (n=28), there were a total of 17 male and 11 female patients. The mean age of the sample population was 50.89±13.40 years. The lesions were more commonly seen is the age group of 41-60 years (57.14%). Out of 44 lesions(n),24 (54.5%) lesionswere benign , 20 (45.45%) were malignant. There were 17 hemangiomas (38.6%), 2 hematomas (4.5%), 2 simple cysts (4.5%), 1 hydatid cyst (2.27%), 2 hepatic adenomas (4.5%), 16 hepatocellular carcinoma (HCC) (36.36%), 3 cholangiocarcinoma (6.8%), and 1 hepatoblastoma (2.27%). DWI has 85% sensitivity and 84.7% specificity for the differentiation of benign from malignant lesions. The mean ADC value of benign lesions was 1.83x10-3mm2/s and the mean ADC of malignant liver lesions was 0.96x10-3mm2/s. In the present study, the average cut off of mean ADC to differentiate benign and malignant bone lesions is 1.3x10-3 mm2/s, with statistically significant p value of 0.001, sensitivity of 95% and specificity of 83.3%. DWI is a valuable imaging technique in the evaluation of focal liver lesions. The ability to differentiate between benign and malignant liver lesions without the need for contrast is a significant benefit, particularly in challenging cases involving uncooperative patients or when contrast administration is contraindicated.