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

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).

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.

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.

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.