Brain imaging and behavior
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Brain Imaging Behav · Mar 2010
Comparative StudyComparison of manual and automated determination of hippocampal volumes in MCI and early AD.
MRI-based hippocampal volume analysis has been extensively employed given its potential as a biomarker for brain disorders such as Alzheimer's disease (AD), and accurate and efficient determination of hippocampal volumes from brain images is still a challenging issue. We compared an automated method, FreeSurfer (V4), with a published manual protocol for the determination of hippocampal volumes from T1-weighted MRI scans. Our study included MRI data from 125 older adult subjects: healthy controls with no significant cognitive complaints or deficits (HC, n=38), euthymic individuals with cognitive complaints (CC, n=39) but intact neuropsychological performance, and patients with amnestic mild cognitive impairment (MCI, n=37) or a clinical diagnosis of probable AD (AD, n=11). ⋯ Results indicated that these two methods derived highly correlated results with strong agreement. After controlling for the age, sex and intracranial volume in statistical group analysis, both the manual tracing and FreeSurfer methods yield similar patterns: both the MCI group and the AD group showed hippocampal volume reduction compared to both the HC group and the CC group, and the HC and CC groups did not differ. These comparisons suggest that FreeSurfer has the potential to be used in automated determination of hippocampal volumes for large-scale MCI/AD-related MRI studies, where manual methods are inefficient or not feasible.
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Brain Imaging Behav · Mar 2010
Neurologic changes during critical illness: brain imaging findings and neurobehavioral outcomes.
Encephalopathy and other neurologic morbidities are common in critical illness, sepsis, and prolonged mechanical ventilation. We assessed structural changes on brain imaging and neuropsychological outcomes in critically ill patients who developed neurological changes during their intensive care unit (ICU) stay. Patients who underwent brain imaging for neurological changes were included in the study. ⋯ Our study demonstrates that abnormalities on brain imaging are common in critically ill patients. We also confirm previous findings that survivors of critical illness have cognitive impairments post-ICU discharge. This study further illustrates the adverse effects of critical illness on the brain and highlights the need for additional research in this emerging area.