Evaluation And Assessment Of Focal Hepatic Lesions Using Diffusion-Weighted Mri

Abstract

Background: MRI is an emerging modality in the detection and evaluation of focal hepatic lesions. The use of various MRI sequences with or without contrast provides better differentiation of abnormal liver parenchyma from normal liver parenchyma. Focal hepatic lesions are an abnormality in the liver parenchyma that can be solid or cystic. They can be primary liver pathology or secondary involvement of the liver due to other abnormalities in the body elsewhere. Diffusion-weighted imaging sequences are more useful in characterizing these lesions. It can be used as a detection and prognostic tool.

 Purpose: To analyse focal hepatic lesions by diffusion-weighted MRI sequences and to differentiate them into benign or malignant using the ADC values.

 Material and Methods: This study included 35 patients who were referred to the department of Radio-diagnosis

at Krishna Institute of Medical Sciences deemed to be university, Karad for assessment of abdominal complaints or already/incidentally detected focal solid hepatic lesions on imaging modality like USG, CT or MRI. All the studied patients were subjected to diffusion-weighted MRI and ADC mapping was done.

 Results: A total of 35 patients were identified to have a focal hepatic lesion, ADC values were calculated from the lesions, and mean ADC values were calculated which are as follows, Hemangioma: 1.66 +/- 0.10 x 10^-3 mm² /sec., Metastasis: 1.11 +/- 0.11 x 10^-3 mm² /sec., Simple hepatic cyst: 2.71 +/- 0.12 x 10^-3 mm² /sec., HCC: 1.17 +/- 0.10 x 10^-3 mm² /sec., Abscess: 0.65 x 10^-3 mm² /sec., Hydatid cyst: 2.9 x 10^-3 mm² /sec., Focal nodular hyperplasia: 1.59 x 10^-3 mm² /sec., Intrahepatic cholangiocarcinoma: 1.24 x 10-3 mm2 /sec., Biliary cystadenocarcinoma: 1.20 x 10^-3 mm² /sec.

The lesion characteristics like size, intensity, diffusion characteristic, and ADC value were recorded. Benign and malignant lesions were confirmed by histopathology and/or imaging studies.

 Conclusion:

This study has demonstrated that malignant lesions show diffusion restriction while benign lesions do not show diffusion restriction. ADC values of benign lesions (excluding abscess) were within the range of 1.43 to 2.92 x 10^-3 mm² /sec., and malignant lesions were within 0.95 to 1.33 x 10^-3 mm² /sec. Benign lesions like hepatic abscess and focal nodular hyperplasia were showing diffusion restriction. Hence in such cases clinical and classical imaging features help us to differentiate them.