NONINVASIVE EVALUATION OF MALIGNANCY OF BRAIN-TUMORS WITH PROTON MR SPECTROSCOPY

PURPOSE: To test clinical proton MR spectroscopy as a noninvasive meth od for predicting tumor malignancy. METHODS: Water-suppressed single-v oxel point resolved spectroscopy in the frontal white matter of 17 hea lthy volunteers and 25 patients with brain tumors yielded spectra with peaks of N-acetyl aspartate (NAA), choline-containing compounds (Cho) , creatine/phosphocreatine (Cre), and lactate. These peak intensities were semiquantitated as a ratio to that of the external reference. The validity of the semiquantitation was first evaluated through phantom and volunteer experiments. RESULTS: The variation in measurements of t he designated region in the volunteers was less than 10%. Normal range s of NAA/reference, Cho/reference, and Cre/reference were 3.59 +/- 0.6 8, 1.96 +/- 0.66, and 1.53 +/- 0.64 (mean +/- SD), respectively. In 17 gliomas, the Cho/reference value in high-grade gliomas was significan tly higher than in low-grade gliomas. Levels of NAA/reference were als o significantly different in low-grade and high-grade malignancy. In e ight meningiomas (four newly diagnosed and four recurrent), the level of Cho/reference was significantly higher in recurrent meningiomas tha n in normal white matter or in newly diagnosed meningiomas. CONCLUSION S: Higher grades of brain tumors in this study were associated with hi gher Cho/reference and lower NAA/reference values. These results sugge st that clinical proton MR spectroscopy may help predict tumor maligna ncy.