Prognostic Implications of Total Hemispheric Glucose Metabolism Ratio in Cerebrocerebellar Diaschisis

Abstract

Diaschisis denotes brain dysfunction remote from a focal brain lesion. We have quantified diaschisis and investigated its prognostic value in glioma. We compared 50F-FDG PET/CT studies collected prospectively from 14 patients with supratentorial glioma (5 men and 9 women; age range, 35-77 y) with 10 single scans from healthy controls (age range, 43-75 y). Dedicated 3-dimensional segmentation software was used to obtain total hemispheric glucose metabolic ratios (THGr) by dividing total hemispheric F-FDG uptake in each diaschitic hemisphere-that is, the ipsilateral cerebral hemisphere (THGr(Ce)) and the contralateral cerebellar hemisphere (THGr(Cb))-by its respective contralateral side. Receiver-operating-characteristic (ROC) analysis was performed to determine optimal cut-offs for combinations of THGr(Ce) and THGr(Cb). Two independent observers obtained data for reproducibility analysis, and THGr values were compared with qualitative assessment of diaschisis performed by a PET neuroimaging specialist. Qualitative analysis confirmed cerebrocerebellar diaschisis in all glioblastoma PET studies performed within 1 y of death. Healthy subjects had significantly higher THGr(Ce) values ( = 0.0007) and THGr(Cb) values ( = 0.02) than glioblastoma patients. ROC analysis yielded diaschisis thresholds of 0.62 for THGr(Ce) and 0.84 for THGr (Cb). Qualitative assessment demonstrated cerebral diaschisis in 16 of 17 (94%) cases with THGr(Ce) below the determined threshold and cerebellar diaschisis in 25 of 26 (96%) cases with THGr(Cb) below the determined threshold. When both THGr(Ce) and THGr(Cb) were below the ROC threshold, the combined diaschisis measures had a positive predictive value for survival below 1 y of 100%. When one parameter was below the threshold, it had a positive predictive value of 75%, and when both parameters exceeded thresholds, the negative predictive value for survival above 1 y was 79%. Median interrater variability was 3.3% and 5.9% for THGr(Ce) and THGr(Cb), respectively. The THGr measures demonstrated diaschisis in the cerebrum and cerebellum of patients with glioma. Combined cerebrocerebellar diaschisis ratios with ROC thresholds for both forebrain and hindbrain had high negative and positive predictive values for survival for less than a year. The THGr method allows comparison of data obtained at different institutions and is now open for further validation in gliomas and other cerebral diseases.

Midazolam Sedation Induces Upper Limb Coordination Deficits That Are Reversed by Flumazenil in Patients with Eloquent Area Gliomas

“…Such maladaptive processes have been reported in patients with intracranial tumors. [22][23][24] Instead of being confined to a single area, the pathologic perturbations from the tumor influence brain across many regions, illustrating complex neural architecture and interconnections. In our study, the phenomenon of diaschisis was hidden in our patients because of adaptive compensation processes, but it was unmasked by midazolam sedation and then hidden again after sedation reversal.…”

Diagnostic manifestations of total hemispheric glucose metabolism ratio in neuronal network diaschisis: diagnostic implications in Alzheimer’s disease and mild cognitive impairment

“…The total hemispheric glucose metabolism ratio (THGr) is an index of the degree of hemispheric lateralization of brain glucose metabolism. The methodology provided evidence of cerebral and cerebellar diaschises in patients afflicted by stroke [15] and glioma [16], yielding prognostic information in the latter (15). Further, cognitive decline in stroke patients with thalamocortical diaschisis has been associated with lateralized hemispheric glucose metabolism [16,17].…”

“…The methodology provided evidence of cerebral and cerebellar diaschises in patients afflicted by stroke [15] and glioma [16], yielding prognostic information in the latter (15). Further, cognitive decline in stroke patients with thalamocortical diaschisis has been associated with lateralized hemispheric glucose metabolism [16,17]. Quantification of glucose metabolism in the neuronal network of the brain may bear evidence of early intra-or interhemispheric disconnectivity related to various conditions including the onset of the AD [7].…”

“…For quantitative analysis of the cerebral FDG-PET images, we used the THGr method described by Segtnan et al in patients with glioma [16]. Each hemisphere was segmented with ROVER software (ABX, Radeberg, Germany).…”

Current Radiopharmaceuticals for Positron Emission Tomography of Brain Tumors

“…The tracer 18 F-fluorodeoxyglucose (FDG) visualizes glucose metabolism, radiolabeled amino acids [e.g., 11 C-methionine, 18 F-3,4-dihydroxyphenylalanine (FDOPA), and O-(2- 18 F-Fluoroethyl)-l-Tyrosine (FET)] perform protein synthesis, and 18 F-fluorothymidine (FLT) performs DNA replications. PET fused with computed tomography (PET/CT) can obtain detailed anatomical information on PET results and provides clinically invaluable information regarding primary detection and differentiation between various underlying tumor types, initial tumor grading and risk stratification, therapy planning, selection of biopsy site, response evaluation, and recurrence detection [ 6 7 8 ]. The current article discusses some of the positive aspects of the contemporary use of PET or PET/CT in primary brain tumors.…”