Development of an integrated multimodal optical imaging system with real-time image analysis for the evaluation of oral premalignant lesions

Abstract

Kortum, "Development of an integrated multimodal optical imaging system with real-time image analysis for the evaluation of oral premalignant lesions," J.Abstract. Oral premalignant lesions (OPLs), such as leukoplakia, are at risk of malignant transformation to oral cancer. Clinicians can elect to biopsy OPLs and assess them for dysplasia, a marker of increased risk. However, it is challenging to decide which OPLs need a biopsy and to select a biopsy site. We developed a multimodal optical imaging system (MMIS) that fully integrates the acquisition, display, and analysis of macroscopic whitelight (WL), autofluorescence (AF), and high-resolution microendoscopy (HRME) images to noninvasively evaluate OPLs. WL and AF images identify suspicious regions with high sensitivity, which are explored at higher resolution with the HRME to improve specificity. Key features include a heat map that delineates suspicious regions according to AF images, and real-time image analysis algorithms that predict pathologic diagnosis at imaged sites. Representative examples from ongoing studies of the MMIS demonstrate its ability to identify high-grade dysplasia in OPLs that are not clinically suspicious, and to avoid unnecessary biopsies of benign OPLs that are clinically suspicious. The MMIS successfully integrates optical imaging approaches (WL, AF, and HRME) at multiple scales for the noninvasive evaluation of OPLs.

Prospective evaluation of oral premalignant lesions using a multimodal imaging system: a pilot study

“…The imaging hardware is connected by USB to a touchscreen laptop, which runs the MMIS software. The MMIS has been previously described in detail; selected details are also provided in the “MMIS Hardware and Automated Analysis” section.…”

“…The number of abnormal nuclei/mm 2 algorithm identified individual nuclei within the image and was used to classify each nucleus as normal or abnormal based on its area and eccentricity . Nuclei with an area > 200 μm 2 , or with an area > 170.8 μm 2 and eccentricity >0.705, were considered abnormal.…”

“…The MMIS classified sites for which 47*(normalized RG ratio) + (Number of Abnormal Nuclei/mm 2 ) > 273 as “high risk” . Sites that did not meet this criteria were “low risk”.…”

“…Recently, we developed a multimodal imaging system (MMIS) which integrates traditional white‐light (WL) evaluation with AF and high‐resolution microendoscopy . AF measures the native tissue autofluorescence of the patient's mucosa using blue excitation light.…”

Algorithm to quantify nuclear features and confidence intervals for classification of oral neoplasia from high-resolution optical images

“…For example, studies have shown that a feature called the number of abnormal nuclei per mm 2 , calculated from HRME images, can distinguish oral cancer and highgrade dysplasia from benign tissue with high accuracy (the ND algorithm). 19,20 One limitation of in vivo microscopy in the oral mucosa is that images frequently contain regions without reliable information about nuclei. For example, leukoplakias, which are the most common oral premalignant lesion, contain a highly scattering keratin layer that overlies the epithelium and can prevent visualization of the subsurface nuclei with good contrast.…”