肠镜下大肠癌组织激光诱发自体荧光光谱特征

Value of LIAF Spectra for Detection of Colorectal Carcinoma During Colonoscopy

目的 探讨在体激光诱发自体荧光光谱判别大肠癌的价值。方法 将与氮分子激光器耦合的同轴石英组合光纤 ,由肠镜活检孔插入 ,分别激发 44例可疑大肠癌病变组织和正常组织 ,产生的荧光由光学多道分析仪Ⅲ分析处理。结果 癌组织的平均荧光积分强度显著低于正常组织 ,分别为 5 6 5 399± 41844和 2 0 8196 6± 115 86 39,P <0 0 0 0 1;癌组织平均主峰波长较正常组织向红光侧移动约 6nm ,P <0 0 0 1;癌组织的主次峰荧光强度比值 (I46 0nm I390nm)比正常组织增大 ,分别为 5 88± 3 5 6和 1 36± 0 70 ,P <0 0 0 0 1。LIAF检出大肠癌的灵敏度、特异度、阳性预测值和阴性预测值分别为 92 6 5 % ,88 0 0 % ,87 5 0 %和 92 96 %。结论 大肠癌与正常组织LIAF光谱特征存在明显差异 。

Objective To assess the value of laser induced autofluorescence(LIAF) spectra for detection of colorectal carcinoma. Methods LIAF spectra were analyzed from 44 patients in whom colorectal carcinoma was suspected. Tissue fluorescence was excited by a nitrogen laser(337 nm) using a quartz optical fiber placed in gentle contact with the area of interest through the accessory channel of a colonoscope, and then the fluorescence emission was collected by the same quartz optical fiber. The LIAF spectra was analyzed using an optical multichanned analyzer (OMA). Results Substantial differences were found in the LIAF spectral properties between normal and cancer tissue. (1) The mean spectrally integrated intensity in vivo from cancer tissue was significantly lower than that from normal tissue with 565 399±41 844 and 2 081 966±1 158 639 rerspectively, P<0 0001;(2) The mean wavelength of main peak from cancer tissue was shifted to the red fluorescence with 6 nm compared with that of normal tissue, P<0 001;(3) The peak intensity ratios of the main peak (460 nm) to the second peak (390 nm) from cancer tissue were higher than that from normal tissue with 5 88±3 56 and 1 36±0 70, respectively, P<0 001;(4) Based on this ratio, the LIAF spectra discriminate cancer tissue from normal tissue with a sensitivity of 92 65%, specificity of 88 00%, positive predictive value of 87 50% and negative predictive value of 92 96%.Conclusions Our findings demonstrate (1) LIAF spectroscopic features of colorectal cancer tissues are markedly different from those of the corresponding normal tissue; (2) LIAF spectra for detecting colorectal cancer tissue is of value in clinical application and is expected to be one of guiding the biopsies to suspicious lesions that are mostly to be malignant; (3) LIAF substantially decreases the number of biopsies obtained from nonmalignant tissue during colonoscopy to detect colon carcinoma.