University of Twente Student Theses


White matter damage and long-term neurological and cognitive outcome after cardiac arrest : a clinical tractography study

Gerards, N.R. (2023) White matter damage and long-term neurological and cognitive outcome after cardiac arrest : a clinical tractography study.

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Abstract:Objective: Cerebral ischemia as a result of cardiac arrest may lead to changes in white matter structure, which can be detected by diffusion tensor imaging (DTI). Therefore, early measures obtained from DTI scans might yield long-term information for the prediction of neurological and cognitive outcome after cardiac arrest. Here, we study the associations between early diffusivity measures in five a priori selected white matter tracts and neurological outcome six months and cognitive performance twelve months after cardiac arrest. Methods: We analysed DTI scans from two ongoing prospective cohort studies. Comatose patients with an MRI scan between 2-9 days were included in our analysis of neurological outcome. Patients that regained consciousness with an MRI scan between 2-30 days were included in our analysis of cognitive performance. Neurological outcome was assessed at six months, dichotomized as good (Cerebral Performance Category (CPC) 1-2) and poor (CPC 3-5). Cognitive performance was defined as either normal (Montreal Cognitive Assessment (MoCA) ≥ 26) or impaired (MoCA < 26). We calculated the mean fractional anisotropy (FA), mean diffusivity (MD), and apparent fiber density (AFD) in five white matter tracts: the genu and body of the corpus callosum, the superior longitudinal fasciculus, the uncinate fasciculus, the cortico-spinal tract, and the thalamo-occipital tract. The measures were compared between patients with good and poor neurological outcome and with normal and impaired cognition. Furthermore, we exploratively compared the mean FA, MD, and AFD in 30 tracts throughout the whole brain. Finally, we compared these measures between the different MRI scanners that were used in our study. Results: Mean FA, MD, and AFD in the five tracts measured within the first week after cardiac arrest were not associated with neurological outcome at six months (n=64; 24 with poor outcome) or cognitive performance at twelve months (n=40; 20 with impaired cognition). Exploratory analyses showed that the FA in the cortico-striatal tracts, thalamocortical tracts and cerebellar peduncles was significantly lower in patients with poor neurological outcome than patients with good outcome. No associations were found between the diffusivity measures in any tract and cognitive performance. Statistically significant inter-vendor differences were found in all three diffusivity measures. Conclusion – Our analysis implicates that the FA in individual tracts holds the potential for outcome prediction of comatose patients after cardiac arrest. However, a pragmatic solution to inter-vendor differences should be found before clinical application can be considered.
Item Type:Essay (Master)
Faculty:TNW: Science and Technology
Programme:Technical Medicine MSc (60033)
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