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Published on: January 23, 2019
Restricted diffusion in the splenium of the corpus callosum after cardiac arrest
1Department of Neurology, Massachusetts General Hospital and Brigham and Women's Hospital, Fruit Street, Wang Ambulatory Center 8th Floor, Boston, MA 02114, USA.
Abstract:
The value of MRI findings for coma prognostication is a question of great clinical and pathological relevance. We describe MRI evidence of restricted diffusion in the splenium in 5 patients with coma after cardiopulmonary resuscitation following cardiac arrest. The most common clinical presentation of corpus callosum lesions (of any cause) is altered mental status, consistent with the global importance of these extensive inter-hemispheric fibers. In our four cases with bilateral splenium restricted diffusion, none of the patients recovered consciousness. One patient with a unilateral (likely embolic) restricted diffusion lesion had excellent recovery. In contrast to unilateral ischemic callosal lesions, we believe that generalized, midline splenium restricted diffusion occurring after cardiopulmonary arrest represents Wallerian degeneration of interhemispheric neurons rather than direct ischemic damage to the white matter or axons of the callosum and thus will likely portend a poor prognosis.
Insights
Diffusion MRI findings in the splenium of the corpus callosum can predict coma prognosis after cardiac arrest. Bilateral splenium restricted diffusion indicates poor outcomes, while unilateral lesions suggest better recovery potential.
Area of Science:
- Neuroimaging
- Neurology
- Pathology
Background:
- Magnetic Resonance Imaging (MRI) is crucial for understanding brain injury after cardiac arrest.
- Coma prognostication relies on identifying neurological markers of damage.
- The corpus callosum's role in inter-hemispheric communication makes its lesions clinically significant.
Purpose of the Study:
- To investigate the prognostic value of MRI-detected restricted diffusion in the splenium of the corpus callosum in patients with post-cardiac arrest coma.
- To differentiate between direct ischemic injury and Wallerian degeneration in corpus callosum lesions.
Main Methods:
- Retrospective analysis of 5 patients with coma following cardiopulmonary resuscitation (CPR) after cardiac arrest.
- Review of MRI scans, specifically diffusion-weighted imaging (DWI), to identify restricted diffusion in the splenium of the corpus callosum.
- Correlation of imaging findings with patient outcomes (consciousness recovery).
Main Results:
- Four patients with bilateral splenium restricted diffusion showed no recovery of consciousness.
- One patient with a unilateral splenium restricted diffusion lesion experienced excellent recovery.
- The findings suggest bilateral midline splenium lesions may represent Wallerian degeneration.
Conclusions:
- Restricted diffusion in the splenium of the corpus callosum on MRI is a significant indicator for coma prognostication after cardiac arrest.
- Bilateral splenium involvement portends a poor prognosis, likely due to Wallerian degeneration.
- Unilateral lesions may indicate a better prognosis, possibly from embolic events.
