Baraga J J, Rava R P, Taroni P, Kittrell C, Fitzmaurice M, Feld M S
George R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge 02139.
Lasers Surg Med. 1990;10(3):245-61. doi: 10.1002/lsm.1900100305.
Ultraviolet excited laser induced fluorescence (LIF) was studied in normal and atherosclerotic human arterial wall in vitro. Using excitation wavelengths from 306 to 310 nm, two distinct emission bands were observed in the LIF of both normal and pathologic aorta: a short wavelength band, peaking at 340 nm emission, which was attributed to tryptophan; and a long wavelength band, peaking at 380 nm emission, which was assigned to a combination of collagen and elastin. The intensity of the short wavelength band was quite sensitive to the choice of excitation wavelength, while the long wavelength band was not, so that the relative contributions of the bands could be controlled by the precise choice of excitation wavelength. A valley in the spectra at 418 nm was attributed to fluorescence reabsorption by oxy-hemoglobin. By using 308 nm excitation to observe emission simultaneously from both the short and long wavelength bands, normal and atherosclerotic aorta were spectrally distinct. Two LIF emission intensity ratios were defined to characterize both the relative tryptophan fluorescence content as well as the ratio of elastin to collagen fluorescence in each spectrum. The differences in these two emission ratios among the various histologic tissue types correlated qualitatively with the histologic and biochemical compositions of these tissues. By combining these parameters in a binary classification scheme, normal and atherosclerotic aorta were correctly distinguished in 56 of 60 total cases. Furthermore, atherosclerotic plaques, atheromatous plaques, and exposed calcifications could be classified individually with sensitivities/predictive values of 90%/90%, 100%/75%, and 82%/82%, respectively.
对正常和动脉粥样硬化的人体动脉壁进行了体外紫外线激发激光诱导荧光（LIF）研究。使用306至310nm的激发波长，在正常和病变主动脉的LIF中均观察到两个不同的发射带：一个短波长带，在340nm发射处达到峰值，归因于色氨酸；以及一个长波长带，在380nm发射处达到峰值，归因于胶原蛋白和弹性蛋白的组合。短波长带的强度对激发波长的选择相当敏感，而长波长带则不然，因此可以通过精确选择激发波长来控制各带的相对贡献。光谱中418nm处的一个谷归因于氧合血红蛋白的荧光重吸收。通过使用308nm激发同时观察短波长带和长波长带的发射，正常和动脉粥样硬化主动脉在光谱上是不同的。定义了两个LIF发射强度比，以表征每个光谱中色氨酸荧光的相对含量以及弹性蛋白与胶原蛋白荧光的比率。不同组织学类型之间这两个发射比的差异与这些组织的组织学和生化组成在质量上相关。通过在二元分类方案中组合这些参数，在60个总病例中的56个中正确区分了正常和动脉粥样硬化主动脉。此外，动脉粥样硬化斑块、粥样斑块和暴露的钙化可以分别进行分类，其敏感性/预测值分别为90%/90%、100%/75%和82%/82%。
