A clinical study of optical biopsy of the uterine cervix using a multispectral imaging system.

OBJECTIVE: To present the clinical application of the multispectral imaging colposcopic system (MIS colposcopy).
METHODS: MIS colposcopy was performed on 123 enrolled women. After a 3% acetic acid application, sequential images were captured, analyzed, and stored automatically. Directed biopsies were taken from distinct marked acetic acid-responsive tissue areas indicated on the monitor, while a real-time assessment of the curves of intensity of the backscattered light (IBSL) vs. time was performed. Blind biopsies were taken from non-acetowhitening areas. Histological findings were correlated with MIS colposcopy results and compared with conventional colposcopy and Pap test results.
RESULTS: Acetic acid-tissue interaction resulted in temporal and spatial alterations to the light scattering properties of the abnormal tissue that was analyzed. The shape of IBSL curve and the "relaxation time" (the time it takes for IBSL to decay to 1/e of its peak value) changed in accordance with the underlying lesion. More severe CIN lesions lead to higher maximum IBSL; longer durations of acetowhitening lead to increasingly delayed exponential decay of IBSL curve. To compare with histological examination, MIS colposcopy had a 1.7% false-diagnostic rate, while PAP test and conventional colposcopy had 24.4% and 22% false-diagnostic rates, respectively. A triple exponential function created a "pseudocolor" image that comprised the grade map of the lesion, and this is frequently representative of the duration/degree of the induced alterations.
CONCLUSION: Improved diagnostic information can be gained by recording the optical information in a narrow spectral range with high spatial resolution. MIS colposcopy can be used in the diagnosis of uterine cervix pathological conditions and in the differentiation between CIN lesions.