Proton MR Spectroscopic Imaging of Prostate Cancer. Metabolite Patterns and Response to External Beam Irradiation

本研究的目的是评估前列腺癌患者外放射治疗后前列腺代谢物的变化。前列腺癌患者盆腔照射量为66.6 Gy。在33.2 Gy照射前、照射后2周和照射后10周分别进行MR光谱成像和血清前列腺特异性抗原（PSA）水平测定。通过1.5 t系统获得二维7 x 7相位编码MR光谱成像数据集，该系统具有用于射频传输的体线圈和可扩展的直肠内线圈。通过对柠檬酸盐和胆碱峰值水平的比较，将前列腺代谢模式分为柠檬酸盐为主模式、胆碱为主模式和胆碱峰值水平低于柠檬酸盐水平但高于柠檬酸盐水平90%的平衡模式。辐照前胆碱优势型平均面积为1.86 = 1.18 cm3。照射后胆碱优势区仍存在，但照射后2周和10周的胆碱优势区分别显著降低至0.85〓0.72 cm3 （p = 0.03）和0.73〓0.40 cm3 （p = 0.01）。

The purpose of this study was to evaluate change in prostate metabolites after external radiation therapy in patients with prostate carcinomas. Patients with prostatic cancer underwent pelvic irradiation 66.6 Gy. MR spectroscopic imaging and the measurement of serum prostate-specific antigen (PSA) levels underwent before irradiation therapy, at 33.2 Gy irradiation, 2 weeks-post irradiation and 10 weeks-post irradiation. A two dimensional 7 x 7 phase encoded MR spectroscopic imaging data set was acquired by a 1.5-T system with the body coil for radio-frequency transmission and an expandable endorectal coil. According to comparisons between citrate and choline peak levels, the metabolite patterns of the prostate were classified into citrate dominant, choline dominant and equilibrium pattern in which choline peak level is lower than citrate level but more than 90 % of citrate level.The mean area with choline dominant pattern before irradiation was 1.86 〓 1.18 cm3. Choline dominant areas were remained after irradiation although those at 2 and 10 weeks-postirradiation were significantly decreased to 0.85 〓 0.72 cm3 (p = 0.03) and 0.73 〓 0.40 cm3 (p = 0.01), respectively.