MR Spectroscopy of the Prostate at 3T: Measurements of Relaxation Times and Quantification of Prostate Metabolites using Water as an Internal Reference

• Published in: Magnetic Resonance in Medical Sciences Vol. 12; no. 4; pp. 289 - 296
• Main Authors: WEIS, Jan, ORTIZ-NIETO, Francisco, AHLSTRÖM, Håkan
• Format: Journal Article
• Language: English
• Published: Japan Japanese Society for Magnetic Resonance in Medicine 01.01.2013
• Subjects: 1H-MRS; 3 tesla; absolute quantitation; Adult; Aged; Biomarkers, Tumor - metabolism; Body Water - metabolism; Choline - metabolism; Citric Acid - metabolism; Creatine - metabolism; Humans; Magnetic Resonance Spectroscopy - methods; Male; Middle Aged; prostate; Prostatic Neoplasms - diagnosis; Prostatic Neoplasms - metabolism; Reference Values; relaxation times; water reference
• ISSN: 1347-3182; 1880-2206
• DOI: 10.2463/mrms.2013-0017

Purpose: We performed single-voxel magnetic resonance spectroscopy (MRS) of the human prostate at 3 tesla using a surface coil to measure prostate water, choline (Cho), creatine (Cr), and citrate (Cit) relaxation times T1, T2, and to estimate concentrations of Cho, Cr, and Cit in healthy volunteers. Methods: In nine of 17 healthy volunteers, we performed experiments to estimate relaxation time, and we used the spectra of the other eight to compute metabolite concentrations. Spectra were processed by LCModel and AMARES (advanced method for accurate, robust, and efficient spectral fitting) algorithms. T1 and T2 values were obtained by monoexponential fitting of the spectral intensities. Metabolite concentrations were estimated using prostate tissue water as an internal concentration reference. Results: Relaxation times are reported for prostate water (T1, 2163±166 ms; T2, 110±18 ms), Cho (T1, 987±71 ms; T2, 239±24 ms), Cr (T1, 1128±149 ms; T2, 188±20 ms), and Cit (T1, 476±70 ms; T2, 228±42 ms). Mean concentrations in healthy prostate were Cho, 2.6±0.3 mM, Cr, 5.8±1.3 mM, and Cit, 26.9±5.5 mM. Conclusion: We observed metabolite relaxation times and concentrations consistent with published values of healthy volunteers at 1.5 and 3T. T1 values increased and T2 slightly decreased with magnetic field strength. Our preliminary patient results indicate that water-referenced quantitative MRS of the human prostate is a promising tool for monitoring therapeutic effects and detecting tumor relapse, i.e., in situations when Cit intensity is small or undetectable.