Evolving Concept Of Non Ischaemic Brain Lesions Through Diffusion Weighted MRI Imaging
Authors: Elkory M A , Mansour H M , Abdelghany A F , Abdeldayem E H 
Published: May 2020

Abstract

Purpose
to assess the role of Diffusion weighted images in evaluation and characterization of non ischemic brain lesions, which is essential in determining appropriate patient management .

Methods and Material
The included 100 patients with different brain lesions other than infarctions (37 males & 63 females) were further classified into 6 groups. These are intracranial infarctions, intracranial hemorrhage, intracranial masses (which is further subdivided into extra-axial and intra-axial masses), traumatic brain lesions, demyelinating diseases and others (encephalopathies and leukodystrophies). Their ages ranged from 8 days to 77 years with a mean age of 37.6 years.

Results
The ADC value of lesions of each group was then compared with that of normal appearing white matter (NAWM) in the same patients.In intracranial infections the ADC values of those lesions that showed true restriction (n = 6/7) ranged from 0.32 x 10-3 mm2/sec to 0.93 x 10-3 mm2/sec (with a mean of 0.63±0.2 x 10-3 mm2/sec) while that of NAWM in the same patients ranged from 0.76 x 10-3 mm2/sec to 0.94 x 10-3 mm2/sec (with a mean of 0.86±0.8 x 10-3 mm2/sec). In intracranial hemorrhage, 6 lesions showed true restriction with ADC values ranging from 0.25 x 10-3 mm2 / sec to 1.0 x 10-3 mm2 / sec (with a mean of 0.71±0.33 x 10-3 mm2 / sec) while the ADC value of the NAWM in the same patients ranged from 0.64 x 10-3 mm2 / sec to 0.7 x 10-3 mm2 / sec (with a mean of 0.68±0.04 x 10-3 mm2 / sec). In extra-axial masses, true restriction was identified in 16 patients with ADC values ranging from 0.43 x 10-3 mm2 / sec to 1.1 x 10-3 mm2 / sec (with a mean of 0.75±0.2 x 10-3 mm2 / sec). The ADC values of NAWM in the same patients ranged from 0.64 x 10-3 mm2 / sec to 0.76 x 10-3 mm2 / sec (with a mean of 0.68±0.04 x 10-3 mm2 / sec). In intra-axial masses, true restriction was identified in 32 patients with ADC values ranging from 0.34 x 10-3 mm2 / sec to 1.1 x 10-3 mm2 / sec (with a mean of 0.82±0.2 x 10-3 mm2 / sec). The ADC values of NAWM in the same patients ranged from 0.6 x 10-3 mm2 / sec to 0.85 x 10-3 mm2 / sec (with a mean of 0.69±0.06 x 10-3 mm2 / sec).

Conclusion
Diffusion MRI (or DWI) imaging has assumed an essential role in the detection of acute brain infarction and in the differentiation of acute infarction from other disease processes. DW MR imaging is also assuming an increasingly important role in the evaluation of many other intracranial disease processes. It shows promising value in the evaluation of intra-cranial infections, tumors, demyelinating diseases, traumatic brain lesiones as well as encephalopathies and leukodystrophies. Further evaluation of the ADC value could be of help especially in the evaluation of the grades of neoplastic processes, evaluation of the prognosis of traumatic brain lesions and in the assessment of the plaques of multiple sclerosis. We concluded that DWI is an essential sequence in the evaluation of different brain lesions and recommend its addition to the routine MRI examination of the brain.