Experimental and clinical study of NMR in pulmonary medicine.

点击翻译按钮获取中文摘要

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.