Statistical Parametric Mapping and Cluster Counting Analysis of [¹⁸F] FDG-PET Imaging in Traumatic Brain Injury

Abstract

In this study we investigated regional cerebral glucose metabolism abnormalities of [(18)F] fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging in traumatic brain injury (TBI). PET images of 81 TBI patients and 68 normal controls were acquired and a word list learning task was administered during the uptake period. The TBI group included 35 patients with positive structural imaging (CT or MRI) findings soon after injury, 40 patients with negative findings, and 6 cases without structural imaging. Statistical parametric mapping (SPM) analysis was applied with several levels of spatial smoothing. Cluster counting analysis was performed for each subject to identify abnormal clusters with contiguous voxel values that deviated by two standard deviations or more from the mean of the normal controls, and to count the number of clusters in 10 size categories. SPM maps demonstrated that the 81 patients had significantly lower FDG uptake than normal controls, widely across the cortex (including bilateral frontal and temporal regions), and in the thalamus. Cluster counting results indicated that TBI patients had a higher proportion of larger clusters than controls. These large low-FDG-uptake clusters of the TBI patients were closer to the brain edge than those of controls. These results suggest that deficits of cerebral metabolism in TBI are spread over multiple brain areas, that they are closer to the cortical surface than clusters in controls, and that group spatial patterns of abnormal cerebral metabolism may be similar in TBI patients with cognitive deficits with and without obvious acute abnormalities identified on structural imaging.

Functional neuroanatomy underlying the clinical subcategorization of minimally conscious state patients

“…Previous work suggested that complementary analyses should be used in studies comprising of traumatic patients. Some of these patients may exhibit extreme focal lesions and, as a result, any statistical inference could be driven by such outliers [28]. Previous studies have located various subprocesses of verbal working memory in structures of the left inferior frontal gyrus [29].…”

Traumatic Brain Injury, Neuroscience, and the Legal System

“…When normal controls are compared with patients with a variety of TBI injuries, PET scans show that, in aggregate, patients with documented TBI had lower glucose uptake across wide swaths of cortex, including the frontal and parietal regions. These areas of reduced metabolism appear even when other CT or MR scans show no particular structural damage [65]. What the study also revealed, though, is that normal controls often have significant areas of hypometabolism too.…”

Neural correlates of malingering in mild traumatic brain injury: A positron emission tomography study

“…We administered 5 mCi of fluorodeoxyglose-F18 (FDG), and during FDG uptake, the patients performed the serial verbal learning test (Hazlett et al, 2010), which has been used in traumatic brain injury studies (Zhang et al, 2009). After approximately 32 min, the patient was positioned in a Siemens/CTI ECAT HR+ scanner (Siemens, Medical Systems, Inc., 810…”

“…Furthermore, while conventional T1-and T2-weighted imaging techniques are relatively insensitive to the detection of mild neurotrauma, position emission tomography (PET) has been used to identify suboptimal brain function in the absence of structural lesions (Ruff et al, 1989;Ruff et al, 1994;Chen et al, 2003;Belanger et al, 2007;Kato et al, 2007;Zhang et al, 2009;Kim et al, 2010;Provenzano et al, 2010;Peskind et al, 2011;Byrnes et al, 2014;Buchsbaum et al, 2015). Thus, we examined patterns of fluorodeoxyglucose-F18 (FDG) uptake in PET studies carried out in veterans with spontaneous failure on the TOMM who participated in a research protocol, were assured of the confidentiality of their test scores, and therefore had no benefit eligibility or financial incentive for poor performance.…”