Discrepancy in core infarct between non-contrast CT and CT perfusion when selecting for mechanical thrombectomy.

Objective: Mechanical thrombectomy (MT) is now an established treatment for acute ischemic stroke (AIS) with large vessel occlusion (LVO) within 6 hours. Since 2018, MT is also recommended from 6-24 hours after selecting with additional multimodal imaging including perfusion imaging. We sought to investigate patients with significant discrepancy in core infarct between computed tomography (CT) and CT perfusion (CTP). Methods: In this retrospective study, patients with AIS who were evaluated for MT using the RAPID software (IschemaView, Redwood City, CA, USA) from February 2018 to March 2019 were included. Cases with discrepancy between infarct volume on non-contrast CT and core volume (cerebral blood flow <30%) as analyzed by RAPID on CTP were analyzed. Results: In the study period, 635 patients were evaluated for acute stroke symptoms. Non-contrast head CT was performed in 635 patients, and CTP with RAPID software post processing was performed in 134 patients. Among the 134 patients, 8 (5.9%) patients had gross discrepancy in core infarct between CT and CTP, with underestimation of infarct by CTP. Evaluation of these cases shows that the likely reason for this discrepancy is recanalization of a LVO, which then leads to erroneously normal or gross underestimate of the core infarct volume determined from CTP post processing analysis. Conclusions: Recanalization of a LVO can lead to erroneously normal or gross underestimation of the core infarct as determined by post processing software analysis of CTP data. The whole composite of hyperacute CT imaging should be examined while making decisions. This caveat of perfusion imaging interpretation has not been reported previously.

Biallelic mutations in human DCC cause developmental split-brain syndrome.

Motor, sensory, and integrative activities of the brain are coordinated by a series of midline-bridging neuronal commissures whose development is tightly regulated. Here we report a new human syndrome in which these commissures are widely disrupted, thus causing clinical manifestations of horizontal gaze palsy, scoliosis, and intellectual disability. Affected individuals were found to possess biallelic loss-of-function mutations in the gene encoding the axon-guidance receptor 'deleted in colorectal carcinoma' (DCC), which has been implicated in congenital mirror movements when it is mutated in the heterozygous state but whose biallelic loss-of-function human phenotype has not been reported. Structural MRI and diffusion tractography demonstrated broad disorganization of white-matter tracts throughout the human central nervous system (CNS), including loss of all commissural tracts at multiple levels of the neuraxis. Combined with data from animal models, these findings show that DCC is a master regulator of midline crossing and development of white-matter projections throughout the human CNS.