Longitudinal MR spectroscopy to detect progression in patients with lower-grade glioma in the surveillance phase

Abstract

Background Monitoring lower grade gliomas (LrGGs) for disease progression is made difficult by the limits of anatomical MRI to distinguish treatment related tissue changes from tumor progression. MR spectroscopic imaging (MRSI) offers additional metabolic information that can help address these challenges. The goal of this study was to compare longitudinal changes in multiparametric MRI, including diffusion weighted imaging, perfusion imaging, and 3D MRSI, for LrGG patients who progressed at the final timepoint and those who remained clinically stable. Methods Forty-one patients with LrGG who were clinically stable were longitudinally assessed for progression. Changes in anatomical, diffusion, perfusion and MRSI data were acquired and compared between patients who remained clinically stable and those who progressed. Results Thirty-one patients remained stable, and 10 patients progressed. Over the study period, progressed patients had a significantly greater increase in normalized choline, choline-to-N-acetylaspartic acid index (CNI), normalized creatine, and creatine-to-N-acetylaspartic acid index (CRNI), than stable patients. CRNI was significantly associated with progression status and WHO type. Progressed astrocytoma patients had greater increases in CRNI than stable astrocytoma patients. Conclusions LrGG patients in surveillance with tumors that progressed had significantly increasing choline and creatine metabolite signals on MRSI, with a trend of increasing T2 FLAIR volumes, compared to LrGG patients who remained stable. These data show that MRSI can be used in conjunction with anatomical imaging studies to gain a clearer picture of LrGG progression, especially in the setting of clinical ambiguity.

The use of advanced neuroimaging modalities in the evaluation of low-grade glioma in adults: a literature review

“…A longitudinal measurement in 41 patients with low-grade glioma demonstrated increasing Cho/NAA concentrations in patients who had progression in their tumor grade, suggesting that MRS may be a viable surveillance tool in addition to traditional MRI follow-up. 12 Another study revealed that over the course of 1 year, a decrease in the Cho concentration within the center of the lesion is correlated to the reduction in tumor volume in patients treated with temozolomide, highlighting the value of MRS in monitoring the response to chemotherapy. 13 Furthermore, Cho/Cr measurements have shown 85.5% discrimination accuracy in differentiating between disease recurrence and radiation injury 14 and 84% discrimination accuracy in differentiating between disease recurrence and pseudoprogression.…”