Diffusion-Weighted Magnetic Resonance Imaging Improves Outcome Prediction in Adult Traumatic Brain Injury

Abstract

In patients with traumatic brain injury (TBI), diffuse axonal injury (DAI) accounts for a significant amount of parenchymal injury. Diffusion weighted magnetic resonance imaging (DWI) is known to be sensitive for detecting visible DAI lesions. We focused on detection of non-visible, quantifiable diffusion changes in specific normal-appearing brain regions, using apparent diffusion coefficient (ADC) maps. Thirty-seven adults with TBI were compared to 35 age-matched control patients. DWI was performed and ADC maps were generated. Thirty-one regions of interest (ROI) were manually drawn on ADC maps and ADC values extracted. Brain ROIs were categorized into five zones: peripheral gray matter, peripheral white matter, deep gray matter, deep white matter, and posterior fossa. ADC results were compared with the severity of injury based on the admission Glasgow Coma Scale (GCS 3-8; severe; GSC 9-15 mild/moderate) and with long-term outcome (6-12 months after injury) using the Glasgow Outcome Scale (GOS 1-3, unfavorable; GOS: 4-5, favorable) score. Mean ADC values in all five brain zones were significantly different between TBI subjects and controls (p<or=0.05). Patients with more severe injury (i.e., GCS 3-8) had significantly different mean ADC values than control patients (p<or=0.05) and patients with unfavorable outcomes had significantly higher mean deep gray and white matter ADC values compared to those with favorable outcomes and to controls (p<or=0.05). Thus, ADC maps can be used to detect non-visible DAI lesions. In addition, injuries in the deep gray and white matter may be useful to predict outcome in adult TBI patients.

A Longitudinal Magnetic Resonance Imaging Study of the Apparent Diffusion Coefficient Values in Corpus Callosum during the First Year after Traumatic Brain Injury

“…Our findings are contradictory to those of some other smaller studies of normal-appearing white matter, 11,13 and could be explained by the differing examination time points of the early MRI or the different regions studied. However, both at 3 and 12 months post-injury, we demonstrated a higher mean ADC value in region IV than in the control group.…”

“…[11][12][13] A DWI study of chronic TBI patients demonstrated increased mean ADC values in both visible lesions and normal-appearing tissue in the corpus callosum. 14 This finding corresponds to the increased MD observed in later DTI studies 5,15,16 and such changes in indices of diffusion are considered to reflect pathology in microstructure and architectural organization.…”

Assessment of White Matter Injury and Outcome in Severe Brain Trauma. A Prospective Multicenter Cohort

“…A number of studies have described the utility of conventional MRI sequences, [18][19][20] diffusion-weighted imaging, 21,22 DTI, 23,24 and susceptibility-weighted imaging 25,26 in patients with TBI. This literature demonstrates the superiority of MRI over CT for the visualization of lesions.…”

Use of multisequence 3.0-T MRI to detect severe traumatic brain injury and predict the outcome

“…33 Previous studies suggest that changes of ADC values in the corpus callosum and BS are associated with the outcomes. 23,34,35 We quantitatively tested the water diffusion in the predilection areas of DAI (CS, corpus callosum and BS) and found that the increased ADC values in patients with TBI were comparable to those in the control subjects, which can be explained by the compromised obstruction of the broken axonal membrane, or they may be due to residual oedema. The ADC values in the CCS and BS were significantly increased in patients with unfavourable outcomes, and the ADC ccs proved to be an independent risk factor for poor prognosis.…”

“…The ADC map was automatically generated by the work station, and 12 regions of interest (ROIs) were manually drawn in the predilection areas of DAI, 23 and their ADC values were recorded ( Figure 1). The ROIs included the following structures: bilateral centrum semiovale (CS), genu, body and splenium of the corpus callosum (CCS) and BS.…”