Mild head trauma: Correlating persistent neurobehavioral sequelae with regional cerebral glucose metabolism and regional cerebral blood flow

Shen Hsing Annabel Chen, Purdue University

Abstract

This study investigated in vivo changes in the regional cerebral uptake of 2-[18F]fluoro-2-deoxy-D-glucose (FDG) and change in regional cerebral blood flow (rCBF) in persons with mild head trauma using positron emission tomography (PET). Patients' persistent reports of cognitive decline following mild head trauma are often not substantiated by structural brain imaging and neuropsychological examination. Physiological imaging of blood flow and metabolism has shown greater promise. However, retrospective designs, inconsistent subject characteristics and examinations, and inadequate study of correlation between physiology and cognitive deficit, make further study necessary. In the present study, 5 patients with mild head trauma and 5 matched healthy controls were imaged, using FDG-PET to measure group and individual differences in normalized regional cerebral glucose metabolism in the resting state. Subjects were also imaged with oxygen-15 labeled water (H2 15O) PET to measure group differences in rCBF changes during a spatial working memory task. MRIs were acquired and used to co-register to the PET images to assist definition of regions of interests (ROI). Neuropsychological testing, behavioral rating of frontal signs, and self-report of post concussion symptoms were also used to quantify participant complaints and cognitive status. Tests of mean difference examined group differences in FDG-uptake, normalized to occipital cortex, and change in rCBF for hypothesized ROIs (anterior temporal and frontal regions, which are preferentially damaged in traumatic brain injury). Results of the resting state study indicated no difference between patient and controls in normalized regional cerebral glucose metabolism during resting state. In the activation state study, there was a trend for participants with mild head trauma to have smaller change in rCBF than controls in two ROIs within the right prefrontal cortical region. However, there were no meaningful relationships between neuropsychological data and symptom complaints with normalized regional cerebral glucose metabolism and change in rCBF. The findings suggest that a cognitive challenge may be more useful than resting state functional neuroimaging in studying the physiologic changes of mild head trauma. A relationship between persistent post concussion symptom complaints in mild head trauma and regional cerebral FDG-uptake and change in rCBF was not substantiated.

Degree

Ph.D.

Advisors

Kareken, Purdue University.

Subject Area

Psychotherapy|Psychobiology|Neurology

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