IN-VIVO DIAGNOSIS OF CERVICAL INTRAEPITHELIAL NEOPLASIA USING 337-NM-EXCITED LASER-INDUCED FLUORESCENCE

Laser-induced fluorescence at 337-nm excitation was used in vivo to di fferentiate neoplastic [cervical intraepithelial neoplasia (CIN)], non neoplastic abnormal (inflammation and human papilloma viral infection) , and normal cervical tissues. A colposcope (low-magnification microsc ope used to view the cervix with reflected light) was used to identify 66 normal and 49 abnormal (5 inflammation, 21 human papilloma virus i nfection, and 23 CIN) sites on the cervix in 28 patients. These sites were then interrogated spectroscopically. A two-stage algorithm was de veloped to diagnose CIN. The first stage differentiated histologically abnormal tissues from colposcopically normal tissues with a sensitivi ty, specificity, and positive predictive value of 92%, 90%, and 88%, r espectively. The second stage differentiated preneoplastic and neoplas tic tissues from nonneoplastic abnormal tissues with a sensitivity, sp ecificity, and positive predictive value of 87%, 73%, and 74%, respect ively. Spectroscopic differences were consistent with a decrease in th e absolute contribution of collagen fluorescence, an increase in the a bsolute contribution of oxyhemoglobin attenuation, and an increase in the relative contribution of reduced nicotinamide dinucleotide phospha te [NAD(P)H] fluorescence as tissue progresses from normal to abnormal in the same patient. These results suggest that in vivo fluorescence spectroscopy of the cervix can be used to diagnose CIN at colposcopy.