Spectroscopy Study Of Identification Between Lower Extremity Arteria Atherosclerotic Plaque And Vessel Wall

Objects:Lower extremity arteriosclerotic occlusive disease (LEAOD) is one of the serious complications of diabetes mellitus, which seriously affect the life of diabetic patients. Laser angioplasty is a new interventional treatment which can open a long occlusion segment in small arteries,so it is particularly suitable for LEAOD of diabetes mellitus.But vascular perforation may occur if improper operation, which now has affected its wide application in clinical.To improve the treatment effect, a real-time monitoring is necessary for laser angioplasty. This study choose laser-induced fluorescence and Raman spectroscopy to differentiate atherosclerotic plaque and vessel wall through in vitro and in vivo experiments, in order to provide a real-time monitoring for laser angioplasty.Methods:1.In vitro experiment:fifteen Japanese male white rabbits, feeding three months with high-fat feed to create atherosclerosis model.Get aortic arch and do portrait incision, using 380 nm UV laser and 532 nm green laser as light source to induce fluorescence spectroscopy of atherosclerotic plaque and vessel wall respectively, and using 532 nm green laser as light source to induce Raman spectroscopy. Analysis the differences of both fluorescence and Raman spectra between them.2.In vivo experiment:six Japanese male white rabbits, feeding three months with high-fat feed to create atherosclerosis model.Anesthesia under sterile conditions, insert self-developed vascular endoscopy with fluorescence diagnosis into proximal part, using 380 nm UV laser to induce fluorescence spectroscopy of atherosclerotic plaque and vessel wall, and analysis the differences between them.Results:1.In vitro experiment:380 nm UV laser-induced fluorescence spectra of atherosclerotic plaque and vessel wall both have characteristic peaks at wavelength of 416 nm, but the intensity of the former(4350±76)is significantly higher than the latter(3082±52),with statistical differences(P<0.05);532 nm green laser-induced fluorescence spectra both have characteristic peaks at wavelength of 800 nm, but no statistical differences exist in intensity(1390±65 and 1416±43,P>0.05);The Raman spectroscopy of atherosclerotic plaque has one peak at wavelength of 3000 nm and one trough at 3300 nm, but the Raman spectroscopy of vessel wall is smooth with no peaks.2.In vivo experiment:the in vivo fluorescence spectra of atherosclerotic plaque and vessel wall both have no characteristic peaks and almost the same with no significant differences.Conclusions:In vitro experiments showed that 380 nm UV laser-induced fluorescence spectra can effectively differentiate atherosclerotic plaque and vessel wall,while 532 nm green laser-induced fluorescence spectra can not. Furthermore, the in vitro experiments also showed that the Raman spectroscopy can differentiate them more directly and effectively than laser-induced fluorescence. However, in vivo experiments showed that 380nm UV laser can not effectively diagnose atherosclerotic plaque, possibly due to blood hemoglobin and other components which may affect the absorption of light-induced fluorescence. This study effectively demonstrate the feasibility of spectroscopy to diagnosis atherosclerotic plaque and provides a basis for further study of real-time monitoring for laser angioplasty.