An inception cohort of 40 children and adolescents with traumatic brain injury and suspected diffuse axonal injury were studied using a new high-resolution magnetic resonance imaging susceptibility-weighted technique that is very sensitive for hemorrhage. A blinded comparison was performed between the extent of parenchymal hemorrhage and initial clinical variables as well as outcomes measured at 6 to 12 months after injury. Children with lower Glasgow Coma Scale scores (< or =8, n = 30) or prolonged coma (>4 days, n = 20) had a greater average number (p = 0.007) and volume (p = 0.008) of hemorrhagic lesions. Children with normal outcomes or mild disability (n = 30) at 6 to 12 months had, on average, fewer hemorrhagic lesions (p = 0.003) and lower volume (p = 0.003) of lesions than those who were moderately or severely disabled or in a vegetative state. Significant differences also were observed when comparing regional injury to clinical variables. Because susceptibility-weighted imaging is much more sensitive than conventional T2*-weighted gradient-echo sequences in detecting hemorrhagic diffuse axonal injury, more accurate and objective assessment of injury can be obtained early after insult, and may provide better prognostic information regarding duration of coma as well as long-term outcome.

SUMMARY: Susceptibility-weighted imaging (SWI) is a high-spatial-resolution 3D gradient-echo MR imaging technique with phase postprocessing that accentuates the paramagnetic properties of blood products such as deoxyhemoglobin, intracellular methemoglobin, and hemosiderin. It is particularly useful for detecting intravascular venous deoxygenated blood as well as extravascular blood products. It is also quite sensitive to the presence of other substances such as iron, some forms of calcification, and air. We have used this technique in the past several years to study a wide variety of pediatric neurologic disorders. We present a review with selected case histories to demonstrate its clinical usefulness in the improvement of the following: 1) detection of hemorrhagic lesions seen in various conditions, including traumatic brain injury and coagulopathic or other hemorrhagic disorders; 2) detection of vascular malformations such as cavernous angiomas, telangiectasias, or pial angiomas associated with Sturge-Weber syndrome; 3) demonstration of venous thrombosis and/or increased oxygen extraction in the setting of infarction, hypoxic/anoxic injury, or brain death; 4) delineation of neoplasms with hemorrhage, calcification, or increased vascularity; and 5) depiction of calcium or iron deposition in neurodegenerative disorders. SWI has provided new understanding of some of these disease processes. It is hoped that as SWI becomes more widely available, it will provide additional diagnostic and prognostic information that will improve the care and outcome of affected children.

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ObjectiveThe diagnosis of multiple sclerosis (MS) presently relies on radiographic assessments of imperfect specificity. Recent data using T2* methodology for the detection of the “central vessel sign” (CVS) in MS lesions suggests this novel MRI technique may distinguish MS from other disorders. Our aim was to determine if evaluation for CVS on 3T FLAIR* MRI differentiates MS from migraine.MethodsPatients with MS or migraine and a prior brain MRI demonstrating at least two hyperintense lesions ≥3 mm were recruited. Exclusion criteria included any additional comorbidity known to cause brain MRI abnormalities. 3T MRI was performed in each participant with administration of gadopentetate dimeglumine, and FLAIR* images were generated in postprocessing. The total number of discrete ovoid lesions ≥3 mm were counted on FLAIR, per participant, and subsequently evaluated for presence of CVS on FLAIR*. An exploratory method evaluating for CVS in a maximum of 12 lesions per subject was also completed.ResultsTen participants with MS and 10 with migraine completed the study. The median percentage (quartiles) of lesions in MS participants with CVS was 84 (79, 94) compared to 22 (15, 54) in migraine (P = 0.008). In a subanalysis by brain region, in the subcortical and deep white matter, the median percentage (quartiles) of lesions in MS participants with CVS was 88 (81, 100) compared to 19 (11, 54) in migraine (P = 0.004). This difference was not identified in juxtacortical, periventricular, or infratentorial regions.InterpretationIdentification of CVS using FLAIR* on 3T MRI helps differentiate MS from migraine, particularly in the subcortical and deep white matter.

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