Experimental and clinical study of NMR in pulmonary medicine.

1. (1)通过松弛时间区分组织：我们在体外测量大鼠肺组织的T1和T2。这些数值在下列实验性肺病变中表现出特征性变化；心源性肺水肿、非心源性肺水肿、活动性放射性肺炎、放射性纤维化和肺炎。所有肺组织的T2均呈多指数横向磁化衰减，由快、慢两种不同的T2值组成。我们推测这两种成分反映了肺组织细胞内和细胞外水的生物学状态。(2)肺组织<^(23)Na>谱：通过向肺动脉注入Na移位剂，使<^(23)Na>发生化学移位，实现肺组织细胞内和细胞外Na的分离。该方法可以观察肺损伤时的水钠动态变化。(1)我们在体外测量人病理肺组织的T1和T2，估计MRI中各病变的信号强度：通过T1和T2在体外可以区分活的肺癌和坏死的肿瘤。炎性肺组织的T1和T2值取决于其急性或慢性（纤维化）的组织学分期。纤维化肺T1、T2值较活细胞肺癌和急性炎性肺明显短。活动性肺癌与炎性肺急性期的松弛时间无显著差异。(2) MRI在肺癌患者中的临床应用：长TR和长TE的T2加权图像对病理肺的定性诊断较好。通过MRI可以区分坏死和纤维化肺与活的肿瘤。结果表明，该方法对肺癌治疗效果的无创评价具有临床应用价值。

1. Animal experiments(1) Tissue discrimination by relaxation times : We measured T1 and T2 or rat lung tissues in vitro. The values showed characteristic change in the follwing experimental lung lesions ; cardiogenic pulmonary edema, non-cardiogenic pulmonary edema, active radiation pneumonitis, radiation fibrosis and pneumonia. The T2 of all lung tissue showed multiexponential transverse magnetization decay consisting of two distinct T2 values of fast and slow. We speculate that these two components reflect the biological state of intra and the extracellular water of lung tissue.(2) <^(23)Na> spectrum of lung tissues : Separation of the intracellular and the extracellular Na of lung tissue was possible by the chemical shift of <^(23)Na> induced by infusing the Na shift agent into the pulmonary artery. This method enables the observation of dynamics of water and sodium in lung injury.2. Application of MRI for lung diseases(1) We measured T1 and T2 of pathological human lung tissues in vitro and estimated the signal intensity of each lesions in MRI : Viable lung cancer and necrotic tumor can be discriminated by the T1 and the T2 in vitro. The value of T1 and T2 in inflammatory lung tissue were dependent on its histological stage of acute or chronic (fibrotic). Fibrotic lung showed significantry short values of T1 and T2 compared to viable lung cancer and acute inflammtory lung. There were not significant differences of relaxation times between viable lung cancer and inflammatory lung in acute stage. (2) Clinical application of MRI in lung cancer patients : The T2 weighted image with long TR and TE was preferable for qualitative diagnsis of pathological lung. Discrimination of necrosis and fibrotic lung from viable tumor was possible by MRI. The results suggested that this method is of value of clinical practice for the non-invasive evaluation of therapeutic effects of lung cancer.