Clinical application of oral contrast-enhanced ultrasound in evaluating the preoperative T staging of gastric cancer

Table 1 Pathological and ultrasonic T staging criteria

T stages	Pathological definition	Ref. ultrasonic imaging
T1a	The tumor invades the lamina propria or the mucosal muscularis layer	Layer 1 (superficial mucosal layer) continuity interrupted, Layer 2 (deep mucosal layer) low-echo thickening, Layer 3 (submucosa) remains continuous
T1b	The tumor invades the submucosa	Layer 3 (submucosa) high-echo continuity interrupted, muscularis propria layer and serosa layer is intact
T2	The tumor invades the muscularis propria	Layer 4 (muscularis propria) low-echo invasion, with the outer layer retaining a smooth echo boundary
T3	The tumor penetrates the subserosal connective tissue but does not invade the visceral peritoneum	Each layer structure completely disappears, but the outermost layer retains a smooth high-echo band (serosal layer)
T4a	The tumor invades the serosal membrane (visceral peritoneum) but not the adjacent structures/organs	Each layer structure completely disappears, and the high-echo band (serosal layer) disappears, or there is a clearly visible serosal layer high-echo line breakthrough with a burr sign or crab foot sign
T4b	Tumors invade the adjacent structures/organs	The whole layer is involved, and the echo boundary between the adjacent organ structure (aorta, pancreas, liver, etc.) disappears, and it adheres with the adjacent organs without relative movement

Table 2 Clinical parameters of gastric cancer patients, n (%)

Clinical parameters	Number of cases
Sex: Male/female	636 (69.9)/273 (30.1)
Age (year)	62.40 ± 11.14
Ultrasound shows the thickness diameter of gastric mass (mm, mean ± SD)	14.24 ± 6.45
Ultrasound shows the maximum upper and lower diameter of gastric mass (mm, mean ± SD)	50.49 ± 22.45
Anatomical location of gastric masses
Cardia & esophagogastric junction	46 (5.0)
Stomach fundus	42 (4.6)
Stomach body	93 (10.2)
Gastric antral	226 (24.8)
Pyloric canal	18 (1.9)
Greater curvature of stomach	51 (5.6)
Lesser curvature of stomach	86 (9.4)
Partial overlapping lesions of stomach	347 (38.1)

Table 3 Comparison of oral contrast-enhanced ultrasound T-stages and pathological T-stages

OCEUS T-stage	No. of cases	Pathological T-stage						Correct diagnosis rate (%)
		T1a	T1b	T2	T3	T4a	T4b
T1a	30	23	7	0	0	0	0	76.66
T1b	33	4	23	6	0	0	0	69.69
T2	94	5	19	59	8	3	0	62.76
T3	296	0	7	22	180	82	5	60.81
T4a	367	0	1	7	14	323	22	88.01
T4b	89	0	0	0	2	8	79	88.76
Summation	909	32	57	94	204	416	106	75.57

OCEUS: Oral contrast-enhanced ultrasound.

Table 4 The diagnostic value of oral contrast-enhanced ultrasound T-staging compared with pathological T-staging of gastric cancer (%)

OCEUS T-stage	Validity			Reliability		Revenue
	Sensitivity	Specificity	Youden index	Coincidence rate	Kappa value	Positive predictive value	Negative predictive value
T1a	71.87	99.2	71.07	98.23	0.73	76.66	98.97
T1b	40.35	98.82	39.17	95.15	0.49	69.69	96.11
T2	62.76	95.71	58.47	92.29	0.58	62.76	95.71
T3	88.23	83.54	71.77	84.59	0.62	60.81	96.08
T4a	77.64	91.07	68.71	84.92	0.69	88.01	82.84
T4b	74.52	98.75	73.27	95.92	0.79	88.76	96.71

OCEUS: Oral contrast-enhanced ultrasound.