Susceptibility-weighted imaging is a high-resolution 3-D T2*-weighted sequence that uses both magnitude and phase information to increase sensitivity for paramagnetic blood products (eg, pediatric TBI studies have detected 6 times as many microbleeds with susceptibility-weighted imaging than with older gradient-echo T2*-weighted sequences) [18]. In addition to detecting subtle structural injury, conventional MRI may help with the prognostication of long-term neurocognitive sequelae. Regarding mild head trauma, a prospective Level 1 trauma multicenter study found that abnormalities on early subacute MRI (eg, small cortical contusions or hemorrhagic axonal injury) are clinically relevant in improving prediction of 3-month outcomes [38]. Another prospective study in patients with mild TBI found a correlation between frontal-temporal-parietal microbleeds on early MRI susceptibility-weighted imaging and the presence or absence of depressive symptoms at 1 year after injury [50]. Regarding moderate to severe head trauma, one study found DAI on subacute MRI in almost three-quarters of patients who survived the acute phase, and only in those patients was GCS score (which tended to be lower) related to 12-month outcomes. It also found similar outcomes for DAI Stage 1 (lobar white matter lesions only) and DAI Stage 2 (callosal lesions), with poor outcomes for DAI Stage 3 (dorsolateral brain stem lesions) [51]. Another study on subacute MRI in post-TBI vegetative states found that depth/stage of DAI lesions helps predict recovery or nonrecovery at 1 year [52]. There is no relevant literature to support the added value or routine use of contrast-enhanced brain MRI instead of noncontrast brain MRI in the initial imaging evaluation of subacute or chronic head trauma. MRI Head with DTI Diffusion-weighted imaging generates a scalar coefficient for each voxel, which represents the average or mean diffusivity (mm2/s) of the water molecules in that location.
Head Trauma PCAs. Susceptibility-weighted imaging is a high-resolution 3-D T2*-weighted sequence that uses both magnitude and phase information to increase sensitivity for paramagnetic blood products (eg, pediatric TBI studies have detected 6 times as many microbleeds with susceptibility-weighted imaging than with older gradient-echo T2*-weighted sequences) [18]. In addition to detecting subtle structural injury, conventional MRI may help with the prognostication of long-term neurocognitive sequelae. Regarding mild head trauma, a prospective Level 1 trauma multicenter study found that abnormalities on early subacute MRI (eg, small cortical contusions or hemorrhagic axonal injury) are clinically relevant in improving prediction of 3-month outcomes [38]. Another prospective study in patients with mild TBI found a correlation between frontal-temporal-parietal microbleeds on early MRI susceptibility-weighted imaging and the presence or absence of depressive symptoms at 1 year after injury [50]. Regarding moderate to severe head trauma, one study found DAI on subacute MRI in almost three-quarters of patients who survived the acute phase, and only in those patients was GCS score (which tended to be lower) related to 12-month outcomes. It also found similar outcomes for DAI Stage 1 (lobar white matter lesions only) and DAI Stage 2 (callosal lesions), with poor outcomes for DAI Stage 3 (dorsolateral brain stem lesions) [51]. Another study on subacute MRI in post-TBI vegetative states found that depth/stage of DAI lesions helps predict recovery or nonrecovery at 1 year [52]. There is no relevant literature to support the added value or routine use of contrast-enhanced brain MRI instead of noncontrast brain MRI in the initial imaging evaluation of subacute or chronic head trauma. MRI Head with DTI Diffusion-weighted imaging generates a scalar coefficient for each voxel, which represents the average or mean diffusivity (mm2/s) of the water molecules in that location.