| Research Abstract |
Using a whole body MRI device, we investigated functional evaluation method of a graft in vivo. First of all, phosphorus compounds in perfused pig livers were measured with ^<31>P-MRS. In this experiments, only inorganic phosphate, PME, PDE and NADH could be observed, because perfusion was not sufficient. Then, we observed phosphorus compounds during perfusion by artificial heart-lung machine in livers isolated from mongrel dogs. In this experiment, high-energy phosphates (HEP) could be observed, and it was suggested that HEP levels in organs are affected by perfusion flow.
In the second experiment, in vivo ^<31>P-MRS was applied for human livers, after designation of regions of interest (DRESS method). In this experiment specific spectrum of the liver were observed. Following this finding, we tried in vivo ^<31>P-MRS in patients before liver operation and found different spectra between cirrhotic liver and cancer-affected livers. This result indicates that the in vivo ^<31>P-MRS is use
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ful method for functional evaluation of the donor liver before harvesting.
Using an experimental NMR device (6.4T), we obtained several basic data for evaluation of in vivo MRS. Changes of spectrum in NMR depending on temperatures were studied in isolated rat hearts for cardiac viability during cold storage. As a result, the spectra obtained at different temperatures could be compared to each other if they are corrected for the influence from changes in T_1 time and probe sensitivity. Following this finding, we assessed the University of Wisconsin solution on isolated rat hearts and found its usefulness. Furthermore, we studied metabolism of phosphates during warm ischemia of perfused livers, and compared the HEP determined by a biochemical method (HPLC) and the HEP determined by NMR.
And, we studied tissue blood flow, pressure volume curves with a conductance catheter and electromicroscopic pathologic assessment in heterotopic dog heart transplantation model. These data may applied for basic data of in vivo MRS measurements. Less
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