Accurate Quantification of Metabolite Ratio in Osteosarcoma Employing Clinical Magnetic Resonance Spectroscopy at 3T; A Comparative Study With Normal Tissue
M, Saligheh Rad
H. Accurate Quantification of Metabolite Ratio in Osteosarcoma Employing Clinical Magnetic Resonance Spectroscopy at 3T; A Comparative Study With Normal Tissue,
Iran J Radiol.
Online ahead of Print
; 11(30th Iranian Congress of Radiology):e21289.
Proton magnetic resonance spectroscopy imaging (1H-MRSI) has recently attracted attention in musculoskeletal applications in general, and in osteosarcoma in particular. Acquired spectra in the MRSI procedure are usually corrupted due to low signal-to-noise ratio (SNR), as well as baseline and residual water contaminations, leading to quantification errors and; therefore, misinterpretation of the ratios calculated by the clinical scanners software.
The aim of this study is accurate quantification of Choline-to-Creatine (Cho/Cr) ratio elevating in osteosarcoma.
Patients and Methods:
Cho/Cr were obtained in 10 patients and 10 healthy volunteers at 3T (Siemens Tim-Trio) by MRSI (PRESS, TR/TE: 2500/135 ms) using a phase-array coil with water-suppression. An extra single voxel spectroscopy (SVS) without water-suppression was acquired to provide phase information for further Eddy-current correction (ECC). Multi-stage preprocessing was applied as follows: ECC, SNR-enhancement and water-removal. Subtract-QUEST-MRSI as a time-domain technique was employed to accurately quantify the metabolite 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) including Alanine, Cho, Cr, Lactate, Lipid and water. Lipids at frequencies of 0.94 and 1.33 ppm were combined to increase accuracy of the Lipid estimation.
The average values of Cho/Cr for 10 patients and 10 volunteers were 0.448 + 0.055 and 0.324 + 0.030, respectively, and the meaningful change of 35% (P < 0.0001) between the two groups. Reliability of the quantitative results was estimated by employing CRB which was about 93.6% among the 10 volunteers.
In this study, we managed to observe meaningful changes in the Cho/Cr ratio in osteosarcoma lesions versus the control group employing 1H-MRSI. The best database for subtract-QUEST-MRSI was optimized in osteosarcoma. Reliability of the quantitative results was about 93.6% among the 10 volunteers.
© 2014, Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited.