Objective: To describe our experience with a noncontact in vivo fluorescence imaging device for the detection and localization of cervical intraepithelial neoplasia (CIN).
Materials and methods: Sixty-two women with abnormal Papanicolaou (Pap) smears, and 4 women with normal Pap smears, were recruited to undergo fluorescence imaging of the cervix during colposcopy. After topically applying dilute acetic acid, the surface of the cervix was scanned with 365 nm ultraviolet light for about 12 sec. Colposcopy and biopsies of visualized lesions were then performed. The fluorescence emission curves generated by normal cervical tissue and various states of cervical pathology were inspected and assigned relative scores of 1-5 based on the height and slope of the curves at peak fluorescence emissions. A score of 1 indicated a curve with high magnitude and distinct peak, and a score of 5 described a curve of low magnitude and rounded/flattened peak. Scores of 2-4 represented curves with incremental changes of about 25% in the height of the curve between scores of 1 and 5. Biopsies were classified as high grade (HG, CIN 2/3), low grade (LG, HPV/CIN 1), or nondysplastic (ND). Among women with abnormal Pap smears, only those who had biopsies with concordant interpretations by two independent pathologists were included in the descriptive analysis. All of the patients with normal Pap smears were included.
Results: A total of 35 women were included in the analysis. Of 62 women with abnormal Pap smears who underwent fluorescence imaging and colposcopy, 31 met the inclusion criteria. Among these 31 women, Pap smears consisted of 6 atypical squamous cells of undetermined significance (ASCUS), 16 low-grade squamous intraepithelial lesions (LGSILs), and 9 high-grade squamous intraepithelial lesions (HGSILs). Of the 4 women with normal Pap smears, 1 had an abnormal colposcopy and a nondysplastic biopsy. Among all 35 women, 42 total biopsies were included, consisting of 11 HG, 25 LG, and 6 ND. Normal squamous tissue generated a score of 1, normal metaplastic tissue a score of 2 or 3, and normal columnar tissue of score of 5 in 35/35 (100%) women. Among the 11 HG lesions, 8 had a score of 4 and 2 had a score of 5. One case was uninterpretable due to a low signal-to-noise ratio. Among the 25 LG lesions, 15 had a score of 3, 6 had a score of 4 or 5, 2 had a score of 1, and 2 cases were uninterpretable.
Conclusions: HG lesions generated spectra distinct from normal tissue in 8/10 (80%) evaluable cases, but LG lesions generated spectra indistinguishable from that of normal metaplastic tissue. Further modifications to this technique are needed before an objective, reproducible, and discriminatory scoring system can be developed. ▪.