前列腺癌治疗前后动态增强MRI评价

目的：应用MRI和动态增强MRI药物代谢动力学模型评价前列腺癌治疗前后的疗效，确定MRI的价值。方法：对16例经组织学证实的前列腺癌分别在治疗前后进行常规和动态增强MRI检查。治疗分别为单纯激素替代治疗(7例)和激素替代治疗加外放射治疗(9例)。MRI检查常规应用GE Signa Advantage 1．5T超导磁共振成像仪，静脉注射Gd-DTPA(0.1mmol/kg体重)。应用两室药物代谢动力学模型分别计算肿瘤病灶、前列腺良性增生和正常前列腺周围带的最大增强指数、对比剂吸收幅度、对比剂的交换率和对比剂分布指数。结果：治疗前PSA由39.54ng/ml降为10．39ng/ml(P＝0．046)，由MRI测量获得的肿瘤体积明显缩小(2．85cm^3至0．84cm^3，P＝0．01)，前列腺良性增生和正常前列腺周围带也明显缩小(P＜0．01)。治疗前后肿瘤病灶最大增强指数和对比剂分布指数降低，但未见统计学差异；对比剂吸收幅度和交换率明显降低(P＝0．004，0．002)。前列腺良性增生的最大增强指数和对比剂分布指数降低(P＝0．284，0．221)；对比剂吸收幅度和交换率明显降低(P＝0．01，0．007)。正常周围带的对比剂吸收幅度、交换率和分布指数明显降低(P＝0．003，0．01，0．04)。结论：动态增强MRI能够全面反映前列腺癌治疗前后的变化，是有效评价前列腺癌治疗疗效的可靠手段。

The evaluation of the prostate cancer with pre and post hormone replacement therapy or/and radiotherapy using dynamic contrast enhanced MRI

Objective:To evaluate the results of prostate cancer after hormone replacement therapy or/and radiotherapy using magnetic resonance imaging (MRI) and two compartment pharmacokinetic model after dynamic contrast enhanced MRI (DCE MRI).Methods:MRI scanning was performed in 16 cases of both per and post treatment prostate cancer who were confirmed by histology.The treatment included the hormone replacement therapy (7 cases) and the hormone replacement therapy plus external beam radiotherapy (9 cases). FSE T 2W images were acquired initially using 1.5T GE Echo speed scanner.This was followed by T 2 weighted thin slice 2D FSE images acquired axially and PD weighted images were obtained using an FSPGR sequence.DCE MRI was then carried out using an FSPGR sequence after Gd DTPA bolus injection of 0.1 mmol/kg.A two compartment model was used to quantify the pharmacokinetic parameters,amplitude,exchanging rate and distribution volume of contrast.The maximum enhancement index was obtained empirically.Results:The PSA value decreased significantly after treatment (P=0.046).The volume of prostate cancer,benign prostate hyperplasia and normal peripheral zone after treatment based on measurement of MR imaging were reduced remarkably than before (P=0.01, 0.000, 0.000, respectively).The decrease on amplitude and exchanging rate of prostate cancer was significantly after treatment than before (P=0.004, 0.002).There was no significantly decrease on the maximum enhancement index and distribution volume of prostate cancer between posttreatment and pretreatment (P=0.196,0.054).Conclusion:DCE MRI can reflect the changes of prostate cancer of pre and post treatment roundly and the DCE MRI is one of the most reliable and effective modality to evaluate the prostate cancer after treatment.