Correlation of myo-inositol levels and grading of cerebral astrocytomas.
OBJECTIVE
In a limited number of patients, the level of myo-inositol (MI), as seen by proton magnetic resonance spectroscopy (HMRS), has been shown to differ for gliomas of different histologic grades. We sought to determine if MI levels correlate with cerebral astrocytoma grade.


METHODS
Five control subjects, 14 patients with low-grade astrocytoma, 10 patients with anaplastic astrocytoma, and 10 patients with glioblastoma multiforme (GBM) underwent single-volume HMRS with an echo time of 20 ms. Twenty-five patients had received surgery, chemotherapy, and/or radiation therapy previously. Using the curve-fitting program supplied by the manufacturer, peak areas for n-acetyl aspartate (NAA), choline (Cho), and MI were normalized with respect to the peak area of creatine (Cr). Ratios for MI/Cr, Cho/Cr, and NAA/Cr were obtained for each lesion and retrospectively compared with the histologic grade of the lesion.


RESULTS
Levels of MI/Cr were higher (0.82 +/- 0.25) in patients with low-grade astrocytoma, intermediate (0.49 +/- 0.07) in control subjects, and lower in patients with anaplastic astrocytoma (0.33 +/- 0.16) and GBM (0.15 +/- 0.12).


CONCLUSIONS
Our study shows a trend toward lower MI levels in the presence of anaplastic astrocytomas and GBMs compared with those of low-grade astrocytomas. MI levels may have implications in the grading of cerebral astrocytomas.
Castillo
M
M
Department of Radiology, University of North Carolina School of Medicine, Chapel Hill 27599-7510, USA.
Smith
J K
JK
Kwock
L
L
D000293:Adolescent; D000328:Adult; D000368:Aged; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D001254:Astrocytoma / Q000737:chemistry / Q000175:diagnosis* / Q000473:pathology; D014408:Biomarkers, Tumor / Q000032:analysis; D001932:Brain Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D002794:Choline / Q000032:analysis; D003401:Creatine / Q000032:analysis; D005260:Female; D005909:Glioblastoma / Q000737:chemistry / Q000175:diagnosis / Q000473:pathology; D006801:Humans; D007294:Inositol / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged
D014408:Biomarkers, Tumor; D001224:Aspartic Acid; D007294:Inositol; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline