Elevated Apparent Diffusion Coefficient of Water in Extra-axial Space following Acute Head Injury

Motivation: The apparent diffusion coefficient (ADC) of water in extra-axial space in patients following acute traumatic brain injury (TBI) can be elevated above the ADC of free water, warranting further study of this phenomenon. Goal(s): To explore ADC dynamics in the extra-axial space of acute TBI patients. Approach: Suspected TBI patients (n=52) with and without traumatic meningeal enhancement (TME) were assessed for elevated ADC in extra-axial space across time. Results: TME patients had elevated ADC values in regions of TME compared to ADC values in the extra-axial space of patients without TME. Baseline elevated ADC predicted TME at 1-week follow-up (p<0.001). Impact: Clinical diffusion imaging may be used to detect TME and predict TME at follow-up without the need for contrast administration, suggesting diagnostic utility for acute TBI patients.The contribution of flow to elevated ADC values will be further explored.