Magnetization transfer imaging of traumatic brain injury

Abstract

Magnetization transfer imaging (MTI) has been shown to be sensitive for the detection of white matter abnormalities in entities such as multiple sclerosis, progressive multifocal leukencephalopathy, and wallerian degeneration. Our hypothesis was that MTI would detect traumatic white matter abnormalities (TWMA) and provide information additional to that obtainable with routine spin‐ and gradient‐echo imaging. We hypothesized that the presence of TWMA defined by MTI would correlate with outcome following TBI. Twenty‐eight victims of head trauma and 15 normal controls underwent magnetic resonance imaging including MTI. Magnetization transfer ratios (MTR) were calculated for areas of shearing injury and for normal‐appearing white matter (NAWM) in locations frequently subject to diffuse axonal injury. Abnormal MTRs were detected in NAWM in eight patients. All eight had persistent neurologic deficits, including cognitive deficits, aphasia, and extremity weakness. Seven of the 28 patients had no abnormal findings on neurologic exam at discharge, transfer, or follow‐up. None of these patients had an abnormal MTR in NAWM. In the remaining 13 patients, who had persistent neurologic deficits, no regions of abnormal MTR were detected in NAWM. MTI is a sensitive method for the detection of TWMA. Detection of abnormal MTR in NAWM that is prone to axonal injury may predict a poor patient outcome. The presence of normal MTR in NAWM in these areas does not necessarily confer a good outcome, however. J. Magn. Reson. Imaging 2000;11:1–8. © 2000 Wiley‐Liss, Inc.

Evaluation of Delayed Neuronal and Axonal Damage Secondary to Moderate and Severe Traumatic Brain Injury Using Quantitative MR Imaging Techniques

“…So, in WM lesions in which demyelination or axonal loss is present, the MTR values decrease, even before conventional MR imaging sequences reveal visible signal-intensity change in the damaged areas. [13][14][15] Reduction of MTR values measured in WM after TBI was already demonstrated 13,16 and also at the CC in victims of mild TBI. 17 We also BFR and BCR, T2-relaxation time, ADC, MTR and NAA/Cr ratio mean value differences between the test and control groups, measured at the NAWM and CC Note:-MRI indicates MR imaging; BFR, bifrontal ventricle-to-brain ratio; BCR, bicaudate ventricle-to-brain ratio; ADC, apparent diffusion coefficient; MTR, magnetization transfer ratio; NAA/Cr, N-acetylaspartate/creatine; NAWM, normal-appearing white matter; CC, corpus callosum.…”

Magnetization Transfer Magnetic Resonance Imaging of the Brain, Spinal Cord, and Optic Nerve

“…120,121 The correlation between MTR changes and subsequent clinical recovery remains controversial. 120 -122 The detection of abnormal MTR values in the NAWM of TBI patients has been shown to predict a poor clinical outcome, but normal MTR findings are not necessarily associated with a good functional recovery.…”

MR Imaging Applications in Mild Traumatic Brain Injury: An Imaging Update

“…MTR abnormalities have been correlated to axonal loss, Wallerian degeneration, and edema (78)(79)(80). Decreased MTR has been shown to correlate with axonal injury and persistent symptoms in moderate to severe TBI (81). Alterations in MTR have also been previously described in mTBI patients (82,83), although a more recent multimodal study did not demonstrate an appreciable difference in MTR between their mTBI cohort and control subjects (84).…”