Application of an artificial intelligence system for endoscopic diagnosis of superficial esophageal squamous cell carcinoma

Table 1 Characteristics of subjects and lesions involved in the testing dataset

Characteristics	Values
Cancerous cases (n = 209)
Age (yr), mean ± SD	62.0 ± 7.2
Sex, Male/Female	158/51
Lesion location, Ce/Ut/Mt/Lt/Ae	2/21/172/14/0
Lesion size (cm), median (Q1, Q3)	2.0 (1.2-4.0)
Paris classification, 0-I/IIa/IIb/IIc/IIa+IIc/III	6/43/112/26/20/2
Circumference, < 1/4, 1/4-1/2, 1/2-3/4, > 3/4	117/63/18/11
Depth of invasion, EP-LPM/MM-SM1/SM2	165/38/6
Non-Cancerous cases (n = 114)
Age (yr), mean ± SD	63.2 ± 5.3
Sex, male/female	65/49
Endoscopic diagnosis, GERD/submucosal lesion/normal	23/5/86

SD: Standard deviation; Ce: Cervical esophagus; Ut: Upper thoracic esophagus; Mt: Middle thoracic esophagus; Lt: Lower thoracic esophagus; Ae, Abdominal esophagus; Q1: Lower quartile; Q3: Upper quartile; EP-LPM: Epithelium or lamina propria; MM-SM1: Muscularis mucosa or submucosal invasion < 200 μm; SM2: Submucosal invasion > 200 μm; GERD: Gastroesophageal reflux disease.

Table 2 Diagnostic performance of the computer-assisted diagnosis system in the testing dataset

	Per-patient analysis				Per-image analysis
	Overall (%)	WLI (%)	NBI (%)	P value	Overall (%)	WLI (%)	NBI (%)	P value
Accuracy (95%CI)	92.9 (89.5-95.2)	89.2 (85.3-92.1)	94.7 (91.7-96.7)	< 0.001	87.5 (85.9-89.0)	85.9 (83.3-88.1)	89.0 (86.8-90.9)	0.156
Sensitivity (95%CI)	91.9 (87.4-94.9)	88.0 (82.9-91.8)	94.3 (90.2-96.7)	< 0.001	86.6 (84.7-88.3)	84.1 (80.8-86.8)	88.4 (86.0-90.4)	0.067
Specificity (95%CI)	94.7 (89.0-97.6)	91.2 (84.6-95.2)	95.6 (90.1-98.1)	0.015	91.7 (88.2-94.3)	90.9 (86.2-94.1)	93.4 (87.0-96.8)	0.750
PPV (95%CI)	97.0 (93.5-98.6)	94.8 (90.8-97.2)	97.7 (94.3-98.9)	0.316	97.9 (96.9-98.5)	96.2 (94.2-97.6)	99.0 (98.0-99.5)	0.004
NPV (95%CI)	86.4 (79.3-91.3)	80.6 (73.0-86.5)	90.1 (83.5-94.2)	0.099	61.1 (56.6-65.4)	67.4 (61.7-72.6)	51.8 (44.8-58.8)	0.003

WLI: White-light imaging; NBI: Narrow-band imaging; PPV: Positive predictive value; NPV: Negative predictive value.

Table 3 Characteristics of lesions that were inaccurately identified by the computer-assisted diagnosis system

Characteristics	Accurate identification (n = 186)	Inaccurate identification (n = 23)	P value
Lesion location, n (%)			1.000
Ce	2 (1.1)	0 (0)
Ut	13 (7.0)	2 (8.7)
Mt	152 (81.7)	20 (87.0)
Lt	19 (10.2)	1 (4.3)
Lesion size (cm), median (Q1, Q3)	2.0 (1.1-4.0)	3 (1.5-3.0)	0.476
Paris classification, n (%)			0.038
Type 0-IIb	95 (51.1)	17 (73.9)
Other non-flat types	91 (48.9)	6 (26.1)
Circumference, n (%)			0.591
< 1/4	107 (57.4)	10 (43.5)
1/4-1/2	54 (29.0)	9 (39.1)
1/2-3/4	16 (8.6)	2 (8.7)
> 3/4	9 (4.8)	2 (8.7)
Depth of invasion, n (%)			0.123
EP-LPM	144 (77.4)	21 (91.3)
MM and deeper	42 (22.6)	2 (8.7)

Ce: Cervical esophagus; Ut: Upper thoracic esophagus; Mt: Middle thoracic esophagus; Lt: Lower thoracic esophagus; Q1: Lower quantile; Q3: Upper quantile; EP-LPM: Epithelium or lamina propria; MM: Muscularis mucosa.