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目的:探讨应用肺通气联合肺灌注磁共振功能成像对犬肺栓塞的诊断作用。方法:选择4只犬于数字减影血管造影(digitalsubstractionangiography,DSA)下经导管将吸收性明胶海绵条注入左下肺动脉后复制肺栓塞动物模型。犬于栓塞前分别吸入室内空气(21%O2)和高浓度氧(99.5%O2)及栓塞后再次吸入高浓度氧行肺通气MRI扫描,分别测出左下肺信号强度,观察反映肺通气的信号强度的变化。犬于栓塞前和栓塞后分别行肺灌注MRI扫描观察左下肺的灌注情况。结果:肺通气MRI扫描时,左下肺栓塞前吸入99.5%O2后较吸入室内空气时的肺实质信号强度明显增加,栓塞后吸入99.5%O2肺实质信号强度亦明显增加,同未栓塞的右下肺相同步骤时的信号强度增加值相比无显著性差异(t=3.685,P>0.05),说明左下肺栓塞后肺通气未受影响。肺灌注MRI扫描时注入造影剂后,右下肺未栓塞区的信号强度迅速上升,于第6.8秒达灌注峰值期,而左下肺栓塞区的时间-信号强度曲线低平,始终未出现明显的灌注峰值期。结论:MRI肺通气氧功能成像联合灌注成像为肺栓塞的诊断提供了一种新的诊断手段,对肺栓塞的诊断是可行的也是有益的。
Objective: To investigate the diagnostic value of pulmonary ventilation combined with pulmonary perfusion MR imaging in the diagnosis of pulmonary embolism in dogs. Methods: Four dogs were selected and injected into the left lower pulmonary artery via digitalis subtraction angiography (DSA). Before embolisation, dogs inhaled indoor air (21% O2) and high-concentration oxygen (99.5% O2) respectively and inhaled high-concentration oxygen again after embolization. Pulmonary ventilation MRI scans were performed to detect the signal intensity of the left lower lung and the signal reflecting the pulmonary ventilation Changes in intensity. Dogs before embolization and embolization after lung perfusion MRI scan were observed left lower lung perfusion. Results: During pulmonary ventilation MRI scan, the pulmonary parenchymal signal intensity was significantly increased after 99.5% O2 inhalation before left lower pulmonary embolism, and the pulmonary parenchymal signal intensity was also significantly increased after 99.5% O2 inhalation. The lower right lower pulmonary embolism There was no significant difference in signal intensity increase in the same stage of lung (t = 3.685, P> 0.05), indicating that pulmonary ventilation was not affected after left lower pulmonary embolism. After contrast media was infused into the MRI scans of lung perfusion, the signal intensity of non-embolized area in the right lower lung increased rapidly, reaching the peak of perfusion at 6.8 seconds, while the time-signal intensity curve of the left lower pulmonary embolism area was low, Infusion peak period. Conclusion: MRI pulmonary perfusion oxygen imaging combined with perfusion imaging provides a new diagnostic tool for the diagnosis of pulmonary embolism. It is feasible and beneficial for the diagnosis of pulmonary embolism.