Leptomeningeal Enhancement Is Associated with Transient Neurologic Deficits after Flow Diversion of Intracranial Aneurysms.

Objective To evaluate the relationship between blood–brain barrier disruption and transient neurologic deficits (TNDs) after neuroendovascular interventions (NEIs) using postcontrast T2/FLAIR (pcFLAIR) imaging. Methods This is a prospective study of 41 consecutive patients undergoing flow diversion therapy for unruptured aneurysm treatment. Patients underwent postprocedural magnetic resonance imaging within 24 hours of the procedure, including diffusion-weighted imaging (DWI) and pcFLAIR sequences. Regression analyses were performed to identify risk factors for developing TNDs. Results In total, 13 patients (31.7%) developed neurologic complications ranging from visual field defects to dense hemiplegia. All deficits were transient, resolving spontaneously within 72 hours. Five of 13 patients (38.5%) with TNDs had presence of lesions on DWI whereas the remaining 8 patients (61.5%) did not. In contrast, all patients who developed TNDs had leptomeningeal enhancement on pcFLAIR imaging, and no patient with normal pcFLAIR imaging developed TNDs. Regression analysis revealed the extent of pcFLAIR enhancement is associated with development of postprocedure neurologic deficits (P < 0.0001). Video electroencephalography monitoring was performed in 4 symptomatic patients manifesting severe deficits. In all instances electroencephalography demonstrated ipsilateral hemispheric slowing and eventual resolution corresponding to ensuing clinical improvement. Only 1 of these 4 patients presented with a lesion on DWI. Conclusions This study challenges conventional dogma that TNDs are ischemic in etiology and suggests blood–brain barrier impairment may be a potential alternative mechanism. These findings are applicable to stroke and other reversible neurologic diseases. Highlights • DWI does not fully explain the present or severity of neurologic deficits after cerebral angiographic procedures. • LME on postcontrast FLAIR is consistent with blood–brain barrier (BBB) impairment and may result in neurologic complications after cerebral angiophy. • pcFLAIR LME is a highly sensitive imaging biomarker of BBB disruption seen in a majority of patients undergoing NEI. • The extent of LME directly predicts the development of reversible neurologic complications seen after NEI. • BBB disruption results in increased permeability of the central nervous system to neurotoxic drugs, which facilitates neurologic dysfunction/TNDs. [ABSTRACT FROM AUTHOR]