This paper reviews the recent developments in the field of biomedical optical imaging, emphasizing technologies that have been moved from ‘bench top to bedside’. Important new developments in this field allow for unprecedented visualization of the tissue microstructure and enable quantitative mapping of disease-specific endogenous and exogenous substances. With these advances, optical imaging technologies are becoming powerful clinical tools for non-invasive and objective diagnosis, guided treatment and monitoring therapies. Recent developments in visible and infrared diffuse spectroscopy and imaging, spectral imaging, optical coherence tomography, confocal imaging, molecular imaging and dynamic spectral imaging are presented together with their derivative medical devices. Their perspectives and challenges are discussed.

Purpose: Colposcopy occupies a key role in the prevention of cervical cancer by identifying preinvasive or invasive lesions. However, colposcopy is subjective and is responsible for 52% of screening failures. Dynamic spectral imaging (DSI) is based on the objective, quantitative assessment of the acetowhitening effect. This study compared DSI with colposcopy. Experimental Design: Women referred for colposcopy were examined simultaneously with colposcopy and DSI using a precommercial DySIS model (FPC-03) in an international, multicenter trial. The colposcopy impression and DySIS values were compared with consensus histology reports of biopsies. Subjects were recruited to a training group and subsequently to a test group. Measures were taken to avoid verification bias. Results: The training and test groups comprised 82 and 308 eligible women, respectively. A cutoff value to identify high-grade disease was selected from the results of the training group and data from previous work. Receiver operator curve analysis of the test data showed an area under the curve of 0.844. DySIS detected 62.9% more high-grade cases than colposcopy (57 versus 35, P = 0.0001). DySIS exceeded end points approved by the Food and Drug Administration for similar studies, with increments in the true positive rate of 22/308 (7.1%; lower 95% CL, 4.5% versus 2%) and in the false positive rate of 32/308 (10.4%; upper 95% CL, 14.7% versus 15%). Conclusions: DySIS is more sensitive than colposcopy in detecting high-grade lesions and can provide improved guidance for biopsy. The results are obtained in a user-independent fashion, making it suitable for use by nursing personnel.

Objective To validate the dynamic spectral imaging (DSI) colposcope's colour-coded map in discriminating high-from low-grade cervical lesions and non-neoplastic tissue.Design Prospective, comparative, multicentre clinical trial.Setting The colposcopy clinics of three Dutch hospitals.Population Women of 18 years or over with an intact cervix, referred for colposcopy.Methods During a 3-minute image acquisition phase, the DSI colposcope was used as a regular video colposcope: the colposcopist located and graded potential lesions based on conventional colposcopic criteria. Subsequently, a colour-coded map was calculated and displayed, representing localisation and severity of the cervical lesion. Biopsies were collected from all atypical sites, as identified by digital mapping and/or conventional colposcopy. Furthermore, one additional biopsy was taken. Main outcome measures Histologically confirmed high-grade cervical disease (CIN2+).Results In total 275 women were included in the study: 183 women were analysed in the 'according-to-protocol' (ATP) cohort and 239 women in the 'intention-to-treat' (ITT) cohort. In the ATP cohort, the sensitivity of DSI colposcopy to identify women with high-grade (CIN2+) lesions was 79% (95% CI 70-88) and the sensitivity of conventional colposcopy was 55% (95% CI 44-65) (P = 0.0006, asymptotic McNemar test). When the DSI colour-coded map was combined with conventional colposcopy, the sensitivity was 88% (95% CI 82-95).Conclusions DSI colposcopy has a significantly higher sensitivity to detect cervical lesions than conventional colposcopy. If the colour-coded map is combined with conventional colposcopic examination, the sensitivity increases further.

This paper describes a novel optical imaging method for the in vivo early detection, quantitative staging, and mapping of cervical cancer and precancer. A multispectral imaging system was developed, which is capable of performing time-resolved imaging spectroscopy. The system was used in order to assess quantitatively the alterations in the light scattering properties of the cervix, induced selectively and reversibly in cervical neoplasias, after the application of acetic acid solution. Spectral imaging and analysis of cervix show that the maximum contrast between acetic acid responsive and nonresponsive areas is obtained at 525 +/- 15 nm, which is further enhanced by cutting off the regular component of tissue reflection, with the aid of two linear cross polarizers. Successive snapshot imaging at this spectral band enables the quantitative assessment of the temporal alterations in the intensity of the backscattered light, in any spatial location of the examined area. Initial clinical trials show that optical contrast enhancement results in a notable improvement of the sensitivity in detecting incipient lesions. It was also shown that the measured temporal characteristics of the phenomenon contain specific information, which enables the differentiation between neoplastic and nonneoplastic lesions, as well as between neoplasias of different grade. The demonstrated improved sensitivity and specificity highlight the potential of the method in both clinical research and noninvasive diagnosis.

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