Double contrast-enhanced ultrasonography improves diagnostic accuracy of T staging compared with multi-detector computed tomography in gastric cancer patients

Table 1 Double contrast-enhanced ultrasonography criteria for T staging of gastric cancer

T stage	Pathological definition	DCEUS criteria
T1	Invasion of the mucosa or submucosa	T1a: In the arterial phase, focal thickening of the mucosa is visualized. The lesion shows slightly delayed hyper-enhancement, similar to the submucosal layer. In the venous phase, the lesion shows hypo-enhancement compared to the submucosal layer. The submucosal layer consistently shows hyper-enhancement and is continuous and intact. The muscular layer shows linear hypo-enhancement and is continuous and intact; T1b: In the arterial phase, focal thickening of the mucosa and submucosa are visualized. The lesion shows homogenous hyper-enhancement, similar to the normal submucosal layer. In the venous phase, the lesion shows hypo-enhancement. The enhancing submucosal layer is continuous. The muscular layer shows linear hypo-enhancement and is continuous and intact
T2	Invasion of the muscularis propria	In the arterial phase, disruption of the mucosa, submucosa and partly muscularis propria are visualized. The lesion shows homogenous hyper-enhancement, similar to the normal submucosal layer. In the venous phase, the lesion shows homogenous hypo-enhancement. The hyper-enhancement strip of submucosal layer and partly hypo-enhancement strip of the muscularis propria are disruptive
T3	Invasion of the subserosal connective tissue without invading the visceral peritoneum	In the arterial phase, disruption of the mucosa, submucosa and muscularis propria are visualized. The lesion shows homogenous hyper-enhancement, similar to the normal submucosal layer. In the venous phase, the lesion shows homogenous hypo-enhancement. The hyper-enhancement strip of submucosal layer and hypo-enhancement strip of the muscularis propria are disruptive. A smooth outer margin of the serosa or a few small linear stranding within the serosa are observed. The enhancing serosa is continuous
T4	Invasion of the serosa (visceral peritoneum) or adjacent structures/organs	In the arterial phase, disruption of the mucosa, submucosa, muscularis propria and serosa are visualized. The lesion shows homogenous hyper-enhancement, similar to the normal submucosal layer. In the venous phase, the lesion shows homogenous hypo-enhancement. The hyper-enhancement strip of submucosal and serosal layers and hypo-enhancement strip of the muscularis propria are disruptive; T4a: An irregular nodular margin of the serosa and densely burred or banded infiltration of the adjacent fat plane are visualized; T4b: The adjacent fat plane between the tumor and the adjacent organ is obliterated or the tumor directly infiltrates the adjacent organ

GC: Gastric cancer; DCEUS: Double contrast-enhanced ultrasonography.

Table 2 Clinicopathological features of patients, n (%)

Features	Total
Sex
Male	137 (59.8)
Female	92 (40.2)
Age (yr; mean ± SD)	54.9 ± 13.0
Pathological T staging
T1a	47 (20.5)
T1b	33 (14.4)
T2	33 (14.4)
T3	59 (25.8)
T4a	53 (23.1)
T4b	4 (1.8)
Location
Upper	17 (7.4)
Middle	70 (30.6)
Lower	122 (53.3)
Entire	20 (8.7)
Histopathological type
Well differentiation	11 (4.8)
Moderately differentiation	45 (19.7)
Poorly differentiation	173 (75.5)
Bormann classification
I	7 (4.7)
II	56 (37.6)
III	70 (47.0)
IV	16 (10.7)
Ulceration
Yes	198 (86.5)
No	31 (13.5)
Tumor size (cm, mean ± SD)	3.5 ± 2.4

Table 3 Comparison of the accuracy for gastric cancer T staging between double contrast-enhanced ultrasonography and multi-detector computed tomography, n (%)

T staging	DCEUS (%)	MDCT (%)	P value
T1 (n = 80)	74 (92.5)	56 (70.0)	< 0.001
T2 (n = 33)	24 (72.7)	17 (51.5)	0.041
T3 (n = 59)	51 (86.4)	27 (45.8)	< 0.001
T4 (n = 57)	50 (87.7)	40 (70.2)	0.022
T total (n = 229)	199 (86.9)	140 (61.1)	< 0.001

DCEUS: Double contrast-enhanced ultrasonography; MDCT: Multi-detector computed tomography.

Table 4 Diagnostic accuracy of double contrast-enhanced ultrasonography and multi-detector computed tomography for gastric cancer T staging based on clinicopathological features, n (%)

Features	Total	Accuracy of DCEUS (%)	Accuracy of MDCT (%)	P value
Location
Upper	17	14 (82.4)	9 (52.9)	0.067
Middle	70	58 (82.9)	40 (57.1)	0.001
Lower	122	110 (90.2)	80 (65.6)	< 0.001
Entire	20	17 (85.0)	11 (55.0)	0.038
Tumor size
< 2.0 cm	78	67 (85.9)	48 (61.5)	< 0.001
≥ 2.0 cm	151	139 (92.1)	97 (64.2)	< 0.001
Ulceration
Yes	198	168 (84.8)	117 (59.1)	< 0.001
No	31	31 (100)	23 (74.2)	0.0051
Borrmann classification
I	7	7 (100)	5 (71.4)	0.4621
II	56	46 (82.1)	27 (48.2)	< 0.001
III	70	58 (82.9)	43 (61.4)	< 0.001
IV	16	14 (87.5)	9 (56.3)	0.1131
Histopathological type
Well differentiation	11	11 (100)	10 (90.9)	0.3061
Moderately differentiation	45	39 (86.7)	20 (44.4)	< 0.001
Poorly differentiation	173	149 (86.1)	110 (63.6)	< 0.001

¹Fisher exact test.

GC: Gastric cancer; DCEUS: Double contrast-enhanced ultrasonography; MDCT: Multi-detector computed tomography.