钆喷酸葡胺磁共振肺灌注成像对猪肺动脉栓塞的诊断价值

MR Gd-DTPA perfusion imaging in diagnosis of pulmonary artery embolization: a pig model study with comparison by DSA

目的:探索磁共振肺灌注成像的最佳剂量及其对肺栓塞的诊断价值。方法:应用0.125、0.25、0.375、0.5和0.625mmol/kg的钆喷酸葡胺(Gd—DTPA)溶液以3 ml/s的流速对6头中华猪进行三维动态增强肺实质灌注成像(机型为SiemensVision 1.5T);之后,用明胶海绵颗粒制备猪肺动脉栓塞模型,再以0.5 mmol/kg剂量和3 ml/s的速度进行肺灌注成像,评价其诊断急性肺栓塞的能力,并与DSA对照。结果:0.125、0.25、0.375、0.5和0.625 mmol/kg 5种剂量时肺组织的强化率分别为(29.07±21.67)％、(60.39±12.21)％、(84.87±8.32)％、(87.80±8.49)％和(81.00±9.98)％;后三者与前两者比较差别有非常显著的意义(P<0.001)。磁共振肺灌注成像肺栓塞病灶显示率为10/10,DSA为8/10;栓塞区表现为楔形低信号灌注缺损。结论:猪肺灌注的满意剂量为0.375～0.5 mmol/kg。肺动脉磁共振血管造影结合肺灌注图像显示肺栓塞比DSA好。

Objective: To optimize the contrast injection protocol for MR pulmonary perfusion imaging (PPI) and to e-valuate its value in the diagnosis of experimental acute pulmonary embolism in pigs. Methods: MR PPI were performed in 6 healthy pigs using the Siemens Vision Plus 1. 5T system and was compared with DSA. The gadolinium contrast medium was injected at a rate 3 ml/s at different doses (0. 125,0. 25,0. 375,0. 5 and 0. 625 mmol/kg). Then the pulmonary embolism models were made in pigs using gelfoam granules, and MR PPI were performed again using 0. 5 mmol/kg dosage at 3 ml/s flow rate, its value in the diagnosis of acute pulmonary embolism was discussed. Results: The satisfied dose for PPI was 0. 375-0. 5 mmol/kg. Although CEMRA was not as good as DSA in demonstrating the small pulmonary arteries, PPI was better than DSA in lung perfusion. MR PPI was better than DSA in demonstrating embolism lesions (100% vs 80%). Pulmonary infarction showed wedge-shaped perfusion defects, whose signal intensity were lower than that of normal areas (137. 86±45. 32 vs 330. 14±46. 52,P<0. 001). Conclusion: The best dose of contrast agent for MR lung perfusion imaging is 0. 375-0. 5 mmol/kg. It also shows that MR PPI is better than DSA in demonstrating pulmonary embolism.