Accurate Quantification of Choline-to-Creatine Ratio as a Biomarker to Distinguish Osteosarcoma Patients from Normal Subjects Employing Proton Magnetic Resonance Spectroscopy Imaging at 3 Tesla

Purpose: This study focused on accurate quantification of a maximum of Choline-to-Creatine ratio (Max (Cho/Cr)) in 10 Osteosarcoma patients, in comparison with 5 healthy volunteers as our control group using proton Magnetic Resonance Spectroscopy Imaging (1H-MRSI). Materials and Methods: Max (Cho/Cr) were obtained in 10 patients with Osteosarcoma over their corresponding ratio maps containing diseased tissue, to be compared with Cho/Cr in 5 healthy volunteers at 3T, employing MRSI (Performed Employing Pointed-resolved Spectroscopy (PRESS), TR/TE: 2500s /135 ms) with water-suppression. An extra unsuppressed water Single-Voxel Spectroscopy (SVS) was acquired to provide phase information for further Eddy Current Correction (ECC). Multi-stage preprocessing was applied. Subtract QUEST MRSI as a time-domain technique was employed to accurately quantify the metabolites’ ratios and to estimate the baseline. Results: An optimal database for Subtract QUEST was achieved based on multiple trials evaluated by acceptable peak-fitting and Cramer-Rao-Bound (CRB). Lipids at frequencies of 0.94 and 1.33ppm were combined to increase the accuracy of the Lipid estimation. Conclusion: Estimation of Max (Cho/Cr) evaluated over Cho/Cr spatial maps to distinguish Osteosarcoma patients from normal subjects suggested that the proposed quantification method leads to high power and linear classifier with a high degree of reproducibility, considering 1H-MRSI at 3T machine as a high efficacy diagnostic tool for musculoskeletal radiology.