Characterization of low-grade gliomas using RGB color maps derived from ADC histograms.
OBJECTIVE
To use normalized apparent diffusion coefficient (nADC) histograms from patients with grade II oligodendroglioma (OD) and astrocytoma (AC) to generate RGB color maps that emphasize the differences between normal-appearing white matter (NAWM), oligo-like, and astro-like regions.


METHODS
NAWM and nonenhancing lesion (NEL) ADC values from 19 ODs and 11 ACs were summed to generate oligo-like (red), NAWM (green), and astro-like (blue) nADC histograms. These nADC histograms were then used to map nADC values to an RGB matrix.


RESULTS
Color maps of oligodendroglial tumor regions were generally visualized in pink, while color maps of astrocytic tumor regions showed various shades of blue. This technique was also applied to 23 patients with the more mixed subtype, oligoastrocytoma (OA), which showed a mixture of both blue and pink, which in many cases appeared to bleed into each other and were blotchy.


CONCLUSIONS
This technique allows for the visualization of biologically different regions within the whole tumor mass, which may aid in directing image-guided biopsies. This can be used to ensure that the biopsy is directed to regions that can more accurately define the dominant tumor characteristics.
Khayal
Inas S
IS
UCSF/UCB Joint Graduate Group in Bioengineering, University of California, San Francisco, California 94158-2330, USA. inas.khayal@radiology.ucsf.edu
Nelson
Sarah J
SJ
D000293:Adolescent; D000328:Adult; D001931:Brain Mapping / Q000379:methods; D001932:Brain Neoplasms / Q000473:pathology*; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D017352:Echo-Planar Imaging / Q000379:methods; D005260:Female; D005682:Gadolinium; D005910:Glioma / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D055815:Young Adult
D003287:Contrast Media; D005682:Gadolinium