Physiologic characterisation of glioblastoma multiforme using MRI-based hypoxia mapping, chemical shift imaging, perfusion and diffusion maps.
OBJECTIVE
A multiparametric, physiologic MRI approach was considered to more completely characterise biopsy-confirmed glioblastoma multiforme (GBM). Chemical shift imaging (CSI) supplied biochemical information in metabolite ratios, while perfusion images provided data on presumed vascularity from regional cerebral blood volume (rCBV) and permeability maps. Diffusion-weighted images were reduced to apparent diffusion coefficient (ADC) maps to evaluate cellularity, and blood oxygen level-dependent imaging was used to create maps of putative hypoxic regions.


METHODS
Six post-treatment GBM patients were scanned at 3-month intervals until recurrence was suggested by conventional MRI parameters, yielding 20 scans for consideration. The percentage of extreme values in each technique that overlapped with other parameters was measured and compared across hemispheres to assess utility.


RESULTS
We found significantly better performance in selecting the diseased hemisphere for overall percent overlap when compared to voxel counts from individual thresholded parameter maps. Parameters were selected on the basis of highest overlap, and corresponding composite overlap maps show increased specificity to likely recurrent regions by reducing the number of falsely positive voxels, and offer insight into relationships between various parameters.


CONCLUSIONS
In a pilot group of patients, percent overlap appears to be sensitive to recurrent disease. When used to combine multiple parameters, voxels containing overlap can specifically target probable recurrent areas.
McMillan
Kathryn M
KM
Department of Medical Physics, University of Wisconsin, Madison, WI, USA. kathryn.mcmillan@vanderbilt.edu
Rogers
Baxter P
BP
Field
Aaron S
AS
Laird
Angela R
AR
Fine
Jason P
JP
Meyerand
M Elizabeth
ME
D001931:Brain Mapping; D001932:Brain Neoplasms / Q000209:etiology / Q000473:pathology*; D002560:Cerebrovascular Circulation; D038524:Diffusion Magnetic Resonance Imaging; D005909:Glioblastoma / Q000209:etiology / Q000473:pathology*; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000209:etiology / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis*