血流敏感性交替反转恢复序列肺灌注成像研究

目的 探讨FAIR作为一种不用对比剂的非侵入性成像方法在肺实质MRI灌注成像中的应用价值.方法 对20名健康志愿者,用SSFSE-FAIR序列进行2个冠状面的扫描(降主动脉中央、肺门层面).计算不同层面双肺的相对灌注值(rPBF)及其比值(rPBFR/rPBFL,R/L).结果 (1)同层面双肺rPBF:降主动脉中央层面,左、右肺灌注差异无统计学意义(P＞0.05,右侧rPBF 87±24,左侧rPBF 87±27);肺门层面,双肺灌注有明显差异(P＜0.05,右侧rPBF 41±15,左侧rPBF 74±25).(2)同侧肺组织不同层面rPBF:双肺rPBF在2个不同层面间差异均有统计学意义(均P＜0.05);降主动脉中央层面的rPBF均高于肺门层面的rPBF.结论 FAIR用于肺实质灌注成像是可行的,由于质子饱和效应的因素,在个别层面左、右肺的灌注有差异;且FAIR可以较敏感的反应重力所致的肺血流分布的不均匀性.

Study of pulmonary parenchyma MRI with flow sensitive alternating inversion recovery

OBJECTIVE: To evaluate the feasibility of pulmonary parenchyma perfusion imaging with flow sensitive alternating inversion recovery (FAIR), which is noninvasive and doesn't necessitate injection of contrast agents. METHODS: A total of 20 healthy volunteers were undergone SSFSE-FAIR imaging. Two coronal perfusion-weighted MR images were acquired, one being the posterior coronal slice, and the other being the middle slice parallel to the right pulmonary artery. The relative pulmonary blood flow (rPBF) values of bilateral lungs were calculated respectively and right to left rPBF ratio (R/L) was also evaluated. RESULTS: (1) The rPBF of the right lung in the posterior coronal slice was 87 +/- 24, not significantly different from that of the left lung (87 +/- 27, P > 0.05) with the R/L of 1.01 +/- 0.04. However, the rPBF of the right lung in the middle coronal slice was 41 +/- 15, significantly lower than that of the left lung (74 +/- 25, P < 0.05) with the R/L of 0.55 +/- 0.05. (2) There were significant differences in the rPBF of the homolateral lung on different slices (both P < 0.05). The rPBF values on the posterior slice of the right and left lungs were both significantly higher than those on the middle slice. CONCLUSION: Pulmonary perfusion with FAIR is feasible, but the perfusion of right and left lung may be different on certain slice due to spin saturation effect. FAIR is also sensitive to reflect perfusion heterogeneity due to gravity effect.