2.1 Selection of images
We retrospectively reviewed all laryngoscopic images from patients with
vocal cord leukoplakia at our institution between October 2018 and
October 2020. The laryngoscope used during this period was the Olympus
BF-H290 (Olympus Medical Systems Corp, Tokyo, Japan). The images were
originally taken by senior expert endoscopists and categorized by 2
imaging techniques: WLI and NBI. According to surgical treatment needed,
we classified the images of vocal cord leukoplakia into two types based
on the pathology[7, 15] (Figure 1 ): 1) a
nonsurgical group (NSG) including
LG dysplasia, and 2) a surgical group (SG)
including HG dysplasia and
invasive carcinoma. When multiple pathological types appeared in a
lesion, senior type was determined.