Proton MR spectroscopy in predicting the increase of perfusion MR imaging for WHO grade II gliomas

Purpose:

To investigate the correlation between the metabolite ratios obtained from proton magnetic resonance (MR) spectroscopy and those obtained from MR perfusion parameters (relative cerebral blood volume [rCBV]) in a cohort of low‐grade glioma (LGG).

Materials and Methods:

Patients underwent prospectively conventional MR, proton magnetic resonance spectroscopy (¹HMRS), and perfusion‐weighted images (PWI). Statistical analyses were performed to determine the correlative and independent predictive factors of rCBVmax and the metabolite ratio thresholds with optimum sensitivity and specificity.

Results:

Thirty‐one patients were included in this study. Linear correlations were observed between the metabolic ratios (lactate [Lac]/creatine [Cr], choline [Cho]/N‐acetyl‐aspartate [NAA], free‐lipids/Cr) and rCBVmax (P < 0.05). These metabolic ratios were determined to be independent predictive factors of rCBVmax (P = 0.027, 0.011 and 0.032, respectively). According to the receiver operating characteristic curves, the cutoff values of the metabolic ratios to discriminate between the two populations of rCBVmax (<1.7 versus = 1.7) were 1.72, 1.54, and 1.40, respectively, with a sensitivity = 75% and a specificity >95% for Lac/Cr.

Conclusion:

This study demonstrated consistent correlations between the data from ¹HMRS and PWI. The Lac/Cr ratio predicts regional hemodynamic changes, which are themselves a useful biomarker of clinical prognosis in patients with LGG. As such, this ratio may provide a new parameter for making improved clinical decisions. J. Magn. Reson. Imaging 2012;35:543‐550. © 2011 Wiley Periodicals, Inc.