Traumatic Cerebral Microbleeds in the Subacute Phase Are Practical and Early Predictors of Abnormality of the Normal-Appearing White Matter in the Chronic Phase

A. van der Eerden, T. van den Heuvel, V. Perlbarg, P. Vart, P. Vos, L. Puybasset, D. Galanaud, B. Platel, R. Manniesing and B. Goraj

American Journal of Neuroradiology 2021;42:861-867.

DOI PMID Cited by ~3

BACKGROUND AND PURPOSE: In the chronic phase after traumatic brain injury, DTI findings reflect WM integrity. DTI interpretation in the subacute phase is less straightforward. Microbleed evaluation with SWI is straightforward in both phases. We evaluated whether the microbleed concentration in the subacute phase is associated with the integrity of normal-appearing WM in the chronic phase. MATERIALS AND METHODS: Sixty of 211 consecutive patients 18 years of age or older admitted to our emergency department <=24 hours after moderate to severe traumatic brain injury matched the selection criteria. Standardized 3T SWI, DTI, and T1WI were obtained 3 and 26 weeks after traumatic brain injury in 31 patients and 24 healthy volunteers. At baseline, microbleed concentrations were calculated. At follow-up, mean diffusivity (MD) was calculated in the normal-appearing WM in reference to the healthy volunteers (MDz). Through linear regression, we evaluated the relation between microbleed concentration and MDz in predefined structures. RESULTS: In the cerebral hemispheres, MDz at follow-up was independently associated with the microbleed concentration at baseline (left: B = 38.4 [95% CI 7.5-69.3], P = .017; right: B = 26.3 [95% CI 5.7-47.0], P = .014). No such relation was demonstrated in the central brain. MDz in the corpus callosum was independently associated with the microbleed concentration in the structures connected by WM tracts running through the corpus callosum (B = 20.0 [95% CI 24.8-75.2], P < .000). MDz in the central brain was independently associated with the microbleed concentration in the cerebral hemispheres (B = 25.7 [95% CI 3.9-47.5], P = .023). CONCLUSIONS: SWI-assessed microbleeds in the subacute phase are associated with DTI-based WM integrity in the chronic phase. These associations are found both within regions and between functionally connected regions. B: linear regression coefficient
Bcmb-conc: linear regression coefficient with microbleed concentration as independent variable
Bcmb-nr: linear regression coefficient with microbleed number as independent variable
MD: mean diffusivity
MDz: Z -score of mean diffusivity, normalized to the healthy control participants
t1: 3 (2-5) weeks after TBI
t2: 26 (25-28) weeks after TBI
TAI: traumatic axonal injury
TBI: traumatic brain injury
FA: fractional anisotropy
MARS: Microbleed Anatomical Rating Scale
GCS: Glasgow Coma Scale