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J Nucl Med. 2017 May;58(5):768-773. doi: 10.2967/jnumed.116.180398. Epub 2016 Oct 27.

Prognostic Implications of Total Hemispheric Glucose Metabolism Ratio in Cerebrocerebellar Diaschisis.

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Department of Nuclear Medicine, Odense University Hospital, Odense, Denmark
University of Southern Denmark, Odense, Denmark.
Department of Nuclear Medicine, Odense University Hospital, Odense, Denmark.
Department of Neurology, Herlev University Hospital, Copenhagen, Denmark.
Centre of Health Economics Research, Odense University of Southern Denmark, Odense, Denmark.
Department of Diagnostic Radiology, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York.
Division of Nuclear Medicine, Department of Radiology, Perelman School of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
Department of Radiology and Nuclear Medicine, Hospital of Southwest Jutland, Esbjerg, Denmark.
Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark.
National Brain Mapping Centre, Shahid Beheshti University (Medical and General Campus), Tehran, Iran; and.
Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, Copenhagen, Denmark.


Diaschisis denotes brain dysfunction remote from a focal brain lesion. We have quantified diaschisis and investigated its prognostic value in glioma. Methods: We compared 50 18F-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 18F-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. Results: Qualitative analysis confirmed cerebrocerebellar diaschisis in all glioblastoma PET studies performed within 1 y of death. Healthy subjects had significantly higher THGr(Ce) values (P = 0.0007) and THGr(Cb) values (P = 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. Conclusion: 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.


FDG-PET/CT; brain; cerebellum; diaschisis; glioma; quantification

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