MSCT灌注成像对积水肾脏单肾功能评价的实验研究

An Experimental Study of MSCT Perfusion in the Half Functional Assessment of Hydronephrotic Kidney

目的采用多层螺旋CT(MSCT)灌注成像技术测定肾积水模型的各项灌注参数,探讨其对积水肾脏单肾功能的诊断价值。材料与方法8周龄以上成年健康雄性实验大白兔20只,制作右侧输尿管部分梗阻模型,分别在梗阻前、梗阻后4周行MSCT灌注扫描、单光子正电子发射计算机体层成像(SPECT)检查及彩色多普勒超声显像(CDFI)检测,取积水肾脏标本,光镜下观察病理学变化。结果梗阻后4周MSCT灌注成像可见肾盂扩张,肾皮质明显变薄,皮、髓质血流量(BF)、血容量(BV)较梗阻前有明显下降(P<0.01),对比剂平均通过时间(MTT)变化无明显差异,肾皮质表面通透性(PS)有轻度下降趋势,但与梗阻前相比,无显著性差异,而肾髓质PS则较梗阻前有显著性降低(P<0.01)。CDFI显示梗阻后肾动脉、肾内动脉收缩期峰值速度(PSV)均降低(P<0.05),舒张末速度(EDV)显著低于梗阻前(P<0.01),阻力指数(RI)显著高于梗阻前(P<0.01)。SPECT测定结果显示梗阻后右肾肾小球滤过率(GFR)均显著低于梗阻前(P<0.001),达峰时间(Tb)显著延长(P<0.001),半排时间(T1/2)显著延长,无测定意义。结论肾积水模型在梗阻前、后皮、髓质MSCT灌注参数的变化以BF、BV下降最明显。此结果与CDFI测定的PSV、EDV及RI所反映的肾血流动力学变化相一致。MSCT灌注技术的出现无疑为临床评价单肾功能开拓了思路,随着MSCT灌注软件的不断发展,其在单肾功能评价方面一定会显示出巨大的临床应用价值。

Objective To evaluate the diagnostic value of MSCT perfusion in assessment of half renal function of hydronephrotic kidney by measuring perfusion parameters of hydronephrotic model with MSCT perfusion techniques. Materials and Methods 20 healthy adult male rabbits aged more than 8 weeks with experimentally induced partial obstruction of right ureter were performed sequential MSCT perfusion, SPECT and CDFI before and 4 weeks after the establishment of hydronephrotic model. The hydronephrotic kidneys were examined at microscopy. Results Pelvicalyceal dilatation and renal parenchymal thinning were found on MSCT. BF and BV values in both renal cortex and medulla were significantly lower than those in the control group （ P 〈 0.01 ）. No significant change in MTT was found and PS of renal cortex was slightly lower than that before obstruction but not significantly while PS of renal medulla was significantly lower than that in the control group （P 〈 0.01 ） . Color duplex flow imaging （CDFI） showed a significant lower peak systolic velocity （PSV） in both renal arteries and veins than that before the obstruction （P 〈 0.05 ）and a more significant decline in end diastolic velocity （EDV） （P 〈 0.01 ）. There was a significant higher resistive index （RI） in the renal and intrarenal arteries 4 weeks after the obstruction （P 〈 0.01 ）. On SPECT. glomerular filtration rate （GFR） of the obstructed kidneys were much lower than those before the obstruction （ P 〈 0.001 ）, Tb were much longer （ P 〈 0.001 ） and T（1/2） were much longer which had no practical significance in measurement. Histologically, the specimen of obstructed kidneys showed cystic dilated renal tubules with some atrophic renal tubules. The tubular epithelial cells were fiat. Lobular structure of some of the glomerulum still remained. Intertubular distance widened because of interstitial fibrosis. Cloudy swelling of the tubular epithelium and prolate nucleus were found. Conclusion BF and BV are perfusion parameters that have the most significance in the post obstructive renal cortical and medullar, MSCT perfusion parameters were consistent with the renal hemodynamie changes reflected by PSV. EDV and RI measured by CDFI. MSCT with perfusion technique can provide anatomic images of high temporal and spatial resolution which the renal function highly accord with that with CDFI, With advance in the software, MSCT perfusion will be of great value in the assessment for renal funetion,