2.1 Data Collection and Study Population
All subjects were patients that underwent laryngoscopy prior to surgery and were diagnosed with malignant or benign laryngeal lesions via pathological diagnosis. All duplicate images, unclear images with low resolution, and images of unexposed vocal folds were excluded from this study. Twenty-six images were excluded from this study.
A total of 2179 laryngoscopy images, including 288 images of malignant lesions and 1891 images of benign lesions from 2179 patients were qualified for inclusion. Each image only displayed a patient’s glottic lesion or tumor. The benign lesion images were composed of 998 vocal polyps, 169 vocal cysts, 276 nodules, 356 vocal leukoplakia, 80 vocal process granuloma, and 12 vocal papillomae. Of the 288 malignant lesions, there were 22 cases of T3 tumors, 62 of T2 tumors, and 204 of T1 tumors. The images were retrospectively collected in 6 hospitals with 5 endoscopic systems including First hospital (n=783, XION EndoSTROB D and Olympus ENF), Second hospital (n=622, Olympus ENF), Third hospital (n=531, Olympus VISER Pro and XION EndoSTROB D), Forth hospital (n=89, XION LCD), Fifth hospital (n=78, Olympus CV170), and Sixth hospital (n=76, Olympus ENF). All images were taken between January 1, 2015, and December 31, 2018. The related information is described in Table 1. All patients in this study underwent the white light laryngoscopic scan and were diagnosed by two experienced doctors. The images were distributed into malignant and benign groups by pathology.