Proton magnetic resonance spectroscopy evaluates the outcome of patients with different grades of glioma undergoing gamma knife surgery postoperatively

Heng Wan1, Subin Yuan2, Ding Lei3

1Chengdu, China 2Chengdu Air-force 45 Hospital 3West China Medical Center, Sichuan University

Keywords: outcome, spectroscopy, gamma knife, Imaging, glioma

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Abstract

     Patients with glioma face a grim prognosis with limited treatment options. Transcranial surgery and radiosurgery are still being the primary treatment. Radiographic changes on conventional MRI are used to evaluate tumour response and progression, but are not predictive of outcome in these patients. More sensitive measures of tumour biology are needed to improve patient management. 
     The goal of this research is to define the role and efficacy of proton magnetic resonance spectroscopy (1H MRS) in patients with glioma after clinical treatment.
     Forty-three patients were treated with gamma knife surgery prospectively
     . Response to gamma knife surgery was evaluated by MRI examinations that included MRI with gadolinium injection and 1H MRS which included standard MRI, single voxel spectroscopy and multi-slice multi-voxel spectroscopy. Scans were performed each three month during each patient''s clinical course. The expressions of metabolites including N-acetylaspartate (NAA), choline (Cho), creatine phosphate (Cr), and lactate (Lac) were calculated as the ratios of Cho to Cr (Cho/Cr) and Cho to NAA (Cho/NAA).
     The Cho/NAA and Cho/Cr ratios were significantly higher in recurrent tumour than in regions of radiation injury. The 1H MRS profile changes more widely and rapidly than tumour volume in glioma progression/glioma recurrence.
     This was a retrospective study.
     This prospective study shows that 1H MRS may be used as a non-invasive tool for predicting and monitoring the clinical response to gamma knife surgery postoperatively and can be used to identify high-risk patients during follow-up.
     Decision making after radiosurgery can be assisted by MR spectroscopy.


Acknowledgements

Project Roles:

H. Wan (), S. Yuan (), D. Lei ()