The role of diffusion-weighted MRI in the evaluation and differentiation of space-occupying brain lesions

Abstract

Objectives: The aim of this study was to assess the role of diffusion-weighted MRI in the evaluation and differentiation of space-occupying brain lesions in patients whose conventional MRI (cMRI) examination revealed abnormal imaging features suggestive of space-occupying brain lesions. Diffusion-weighted imaging provides information about the physiological properties of the tumor that have been linked to cellularity, structural integrity, and necrotic transformation of brain or tumor tissue. MR diffusion imaging has become a powerful, multifaceted tool both for very basic clinical needs and for advanced, specialized diagnosis and treatment planning. Background: This study included 75 patients who presented with acute focal neurological deficit or with manifestations of space-occupying brain lesions. All of these patients were subjected to cMRI examination of the brain and to diffusion-weighted MRI. Postprocessing of apparent diffusion coefficient (ADC) maps was generated for all patients. Standard mean ADC values were calculated automatically and expressed in 10−S mm2/s. The cutoff value of 1 × 10−3 mm2/s was used to differentiate restricted areas from nonrestricted areas. Patients and methods: Among the 75 studied patients, the final diagnosis was intracranial neoplastic lesions (group A) in 46 patients (61.3%), non-neoplastic tumor-like lesions (group B) in 17 patients (22.6%), intracranial suppuration (group C) in seven patients (9.3%), and intracerebral hemorrhage (group D) in five patients (6.6%). Analysis of calculated ADC values using the t-test, the U-test, analysis of variance, and the c2-test revealed statistical difference of ADC values between high-grade/low-grade gliomas, abscesses, and intracranial necrotic neoplasms including glioblastoma multiforme, lymphoma/high-grade astrocytoma, medulloblastoma/ependymoma and pilocytic astrocytoma, and epidermoid/arachnoid cysts. Results On the basis of simplicity of the method and the results obtained, diffuse-weighted imaging should be used routinely as a valuable noninvasive tool besides cMRI, whenever available, to reach a definitive final diagnosis.