肺通气氧功能成像对区域性肺通气信息的实验观察(英文)

Pulmonary ventilation oxygen functional imaging for regional pulmo nary ventilation information: an experimental study of dogs

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。

AIM:To explore the diagnostic effect of pulmonary ventilation- perfusion fMR I for pulmonary embolism(PE). METHODS:Gelatin sponge was introduced into the left lower lobar pulmonary art eries of 4 dogs through catheter under digital subtraction angiography(DSA) so a s to establish PE model.Before PE,the dogs inhaled room air(21% O2) and 99.5% O2 respectively and inhaled 99.5% O2 again after PE.Then MRI scanning was perfo rmed for pulmonary ventilation.The signal intensities(SI) of left lower lobe wer e measured and its variation was observed.The dogs were undergone MRI scanning b efore and after PE to observe the perfusion of left lower lobe. RESULTS:Both before and after PE the SI of left lower lobe after inhalation o f 99.5% O2 increased significantly much more than after inhalation of indoor ai r.However,there was no significant difference in the increase of SI value betwee n the embolic left lower lobe and non- embolic region of the right lower lobe(t =3.685,P >0.05),indicating that pulmonary ventilation was not influenced in the embolic region of left lower lobe.During perfusion MR scanning and after injecti on of contrast media,the SI of non- embolic region in the right lower lobe rapi dly increased and reached the peak 6.8 seconds after injection of contrast media .But the time- signal intensity curve of the embolic region of left lower lobe remained at lower level and had no apparent peak value all the time. CONCLUSION:Oxygen- enhanced ventilation fMRI combining perfusion fMRI provid e a new diagnostic means for PE.The method is feasible and beneficial for PE dia gnosis.