Prognostic significance of parameters derived from co-registered¹⁸F-fluorodeoxyglucose PET and contrast-enhanced MRI in patients with high-grade glioma

Abstract

Objective: The aim of this study was to determine the prognostic significance of the volume and intensity of abnormal 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET) accumulation within areas of contrast enhancement on post-therapeutic volumetric MRI. Methods: A total of 10 patients with Grade III or IV glioma were treated with resection followed by intracavitary radiation therapy with 131 I-labelled antitenascin monoclonal antibody. Patients underwent serial FDG-PET and 1.5 T MR imaging. For each patient, MR and FDG-PET image volumes at each time point were aligned using a rigid-body normalised mutual information algorithm. Contrast-enhancing regions of interest (ROIs) were defined using a semi-automated k-means clustering technique. Activity within the ROI on the co-registered PET scan was calculated as a ratio (mean activity ratio; MAR) to activity in contralateral normal-appearing white matter (NAWM). The PET lesion was defined as the portion of the ROI associated with activity greater than two standard deviations above the mean in NAWM. Survival was assessed using the logrank test. Results: Larger contrast-enhancing ROIs were strongly associated with an increased MAR (r50.51; p,0.002). Enhancing lesions with an MAR .1.2 were associated with decreased survival (p,0.016). In nine patients who died, the MAR on PET correlated inversely with survival duration (r520.43; p,0.01), whereas PET lesion volume did not. Conclusion: Following intracavitary radiation therapy, the development of contrastenhancing lesions that are associated with high mean FDG-PET accumulation suggests poor prognosis.

MRI combined with PET-CT of different tracers to improve the accuracy of glioma diagnosis: a systematic review and meta-analysis

“…Another point worthy of note is that studies suggest there is no obvious link between PET lesion volume and survival in patients. The intensity of FDG uptake of tumor may instead be a more powerful predictor of survival [ 52 ].…”

Multiparametric MRI and [18F]Fluorodeoxyglucose Positron Emission Tomography Imaging Is a Potential Prognostic Imaging Biomarker in Recurrent Glioblastoma

“…Several studies have evaluated the utility of post-treatment FDG-PET tumor-to-normal brain ratios in predicting survival in patients with malignant gliomas, including GBM with mixed results ( 40 – 43 ). A study by Barker et al graded FDG-PET scans by comparing ROI uptake to the contralateral normal cortex in 55 patients with recurrent malignant glioma, 39 of which had GBM ( 19 ).…”

Standard clinical approaches and emerging modalities for glioblastoma imaging

“…Although 18FDG PET has been used in this setting, LNAA PET can reliably distinguish tumor progression from treatment-related effects and can in turn identify responders to antiangiogenic therapy with near complete diagnostic accuracy. 163–165 The European Association of Nuclear Medicine (EANM), the Society of Nuclear Medicine and Molecular Imaging (SNMMI), the European Association of Neurooncology (EANO), and the working group for Response Assessment in Neurooncology with PET (PET-RANO) have jointly published guidelines for appropriate use of PET imaging in evaluation of gliomas. 166 …”