Department of Obstetrics and Gynecology, Ludwig Maximilians University Munich, Großhadern Medical Campus, Marchioninistr. 15, 81377, Munich, Germany,
Lasers Med Sci. 2015 Feb;30(2):517-25. doi: 10.1007/s10103-014-1674-5. Epub 2014 Dec 14.
Optical coherence tomography (OCT) can be used as an adjunct to colposcopy in order to detect precancerous and cancerous cervical lesions. Optical clearing agents (OCAs) temporarily reduce the optical scattering of biological tissues. The purpose of this study was to investigate their influence on OCT imaging. OCT images were taken from unsuspicious and suspicious areas of fresh conization specimens immediately after resection and 5, 10, and 20 min after application of dimethyl sulfoxide (DMSO) or polyethylene glycol (PEG). Corresponding histologies were obtained from all sites. The images taken 5, 10, and 20 min after application of OCA were compared to the initial images with respect to changes in brightness, contrast, and scanning depth using a standard nonparametric test of differences of proportions. Further, mean intensity backscattering curves were calculated from all OCT images in the histological groups CIN2, CIN3, inflammation, and normal epithelium. Mean difference profiles within each of these groups were determined, reflecting the mean differences between the condition before the application of OCA and the exposure times 5, 10, and 20 min, respectively. The null hypothesis was tested employing the Dicky-Fuller-test, Hotelings-test and run test. The visual analysis of 434 OCT images from 109 different sites of 24 conization specimens showed a statistically significant increase in brightness and contrast for normal and dysplastic epithelium after application of DMSO or PEG. Further, the analysis of mean intensity profiles suggests the existence of an increased backscattering intensity after application of DMSO or PEG. DMSO and PEG contribute substantially to optical clearing in cervical squamous epithelium and therefore influence OCT imaging in a positive way. With further refinement of the OCT technology, the observed changes may be beneficial in interpreting the tissue microstructure and identifying cervical intraepithelial neoplasia.
光学相干断层扫描（OCT）可作为阴道镜检查的辅助手段，用于检测宫颈癌前病变和癌症病变。光学透明剂（OCA）可暂时降低生物组织的光散射。本研究旨在探讨其对 OCT 成像的影响。在切除后立即、以及在应用二甲基亚砜（DMSO）或聚乙二醇（PEG）后的 5、10 和 20 分钟，从新鲜的锥形切除标本的可疑和非可疑区域采集 OCT 图像。所有部位均获得相应的组织学图像。使用差异比例的标准非参数检验，比较 OCT 图像在应用 OCA 后 5、10 和 20 分钟时的亮度、对比度和扫描深度的变化。进一步，从组织学 CIN2、CIN3、炎症和正常上皮的所有 OCT 图像中计算平均背散射强度曲线。确定这些组中每个组的平均差异分布，反映在应用 OCA 之前的条件与应用后的 5、10 和 20 分钟的暴露时间之间的平均差异。采用 Dicky-Fuller 检验、Hotelling 检验和运行检验检验零假设。对 24 例锥形切除标本的 109 个不同部位的 434 个 OCT 图像进行的视觉分析显示，应用 DMSO 或 PEG 后，正常和发育不良上皮的亮度和对比度均有统计学显著增加。此外，平均强度分布的分析表明，应用 DMSO 或 PEG 后背散射强度增加。DMSO 和 PEG 对宫颈鳞状上皮的光学透明化有很大贡献，因此以积极的方式影响 OCT 成像。随着 OCT 技术的进一步改进，观察到的变化可能有益于解释组织微观结构和识别宫颈上皮内瘤变。
