Diffusion‐ and perfusion‐weighted MR imaging in a patient with acute demyelinating encephalomyelitis (ADEM)

Abstract

To monitor changes of brain tissue metabolism in acute demyelinating encephalitis (ADEM), we examined a patient with suspected ADEM by serial MRI including diffusionand perfusion-weighted imaging (DWI, PWI). Within the inflammatory tissue, the apparent diffusion coefficients were reduced, normal, and increased. Perfusion varied between reduced and normal values, except for small hyperperfused regions. Combining standard MRI with DWI and PWI may elucidate different overlapping phases in cerebral inflammation.

Advanced MR Imaging Techniques in the Diagnosis of Intraaxial Brain Tumors in Adults

“…In tumefactive demyelinating lesions, rTBV values tend to be lower than those in normal brain tissue (33). Highgrade primary neoplasms and metastatic lesions have higher rTBV values than do tumefactive demyelinating lesions (Fig 9c) (23).…”

“…Most tumefactive demyelinating lesions have elevated ADC values, although occasionally, acute demyelinating lesions may have areas of reduced ADC values (Fig 9b) (33).…”

MR Perfusion Imaging in Acute Herpes Simplex Encephalitis

“…This might suggest that the increased perfusion in herpetic inflammatory disease as already described in nuclear medicine studies can also be visualized with MR perfusion images. Contrast-enhanced MR perfusion imaging studies have been reported in other inflammatory diseases like ADEM and multiple sclerosis [8][9][10][11][12]. In ADEM, normal or decreased rCBF values were depicted.…”

“…MR perfusion imaging following a bolus injection of Gd-DTPA does also allow imaging of different perfusion parameters in brain tissue. Its major applications are perfusion measurements in acute stroke patients, but also inflammatory diseases like multiple sclerosis are under investigation [8][9][10][11][12].…”

Clinical Applications of Diffusion

“…Although acute enhancing lesions in MS or acute disseminated encephalomyelitis most frequently have elevated diffusion, they can have transiently restricted diffusion at their periphery or even in their core, usually attributed to cytotoxic edema, fluid shifts between IC and EC compartments, or dense inflammatory cell infiltration [208][209][210][212][213][214] (Fig. 2.23, Table 2.12).…”