Abstract
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.
ABBREVIATIONS:
- 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
Footnotes
This is an investigator-initiated study supported by Trauma Regio Oost, Radboudumc, Nijmegen, and by Stichting Fonds Catharine van Tussenbroek (travel grant). The funding organizations did not participate in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, and approval of the manuscript; and the decision to submit the manuscript for publication.
Disclosures: Anke van der Eerden—RELATED: Grant: Trauma Regio Oost, Radboudumc, Nijmegen, The Netherlands, Comments: Investigator-initiated study supported by Trauma Regio Oost, Radboudumc, Nijmegen. The funding organization did not participate in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, and approval of the manuscript; and the decision to submit the manuscript for publication*; Support for Travel to Meetings for the Study or Other Purposes: Stichting Fonds Catharine van Tussenbroek, Comments: Partial reimbursement of travel expenses from Nijmegen to Paris to facilitate our collaboration. The funding organization did not participate in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, and approval of the manuscript; and the decision to submit the manuscript for publication; UNRELATED: Employment: Erasmus Medical Center, Comments: clinical neuroradiologist and head and neck radiologist. Louis Puybasset— UNRELATED: Stock/Stock Options: BrainTale co-founder. *Money paid to institution.
- © 2021 by American Journal of Neuroradiology