Predicting T and N Staging of Resectable Gastric Cancer According to Whole Tumor Histogram Analysis About a Non-Cartesian k-Space Acquisition DCE-MRI: A Feasibility Study

Figures & data

Figure 1 Study workflow diagram of patient selection.

Figure 2 Male, 63 years old. The pathological diagnosis is intramucosal adenocarcinoma. The lesion invades the submucosa of the lesser curvature of stomach and is determined to be T1 stage. (A) ROI was manually drawn on whole lesions in late arterial phase. Corresponding parametric maps of Ktrans (B), Kep (C) and Ve (D) are created automatically. The corresponding mean values of Ktrans, Kep and Ve are 0.587 /min, 0.491 /min and 0.970, respectively. The histogram of tumor (E) demonstrates that the skewness, kurtosis and entropy are -0.899, 0.207 and 2.807, respectively.

Figure 3 Male, 65 years old. The pathological diagnosis is poorly differentiated adenocarcinoma. The lesion invades the muscular layer of the cardiac wall and is determined to be T2 stage. (A) ROI was manually drawn on whole lesions in late arterial phase. Corresponding parametric maps of Ktrans (B), Kep (C) and Ve (D) are created automatically. The corresponding mean values of Ktrans, Kep and Ve are 0.570 /min, 1.418 /min and 0.402, respectively. The histogram of tumor (E) demonstrates that the skewness, kurtosis and entropy are 0.315, 0.147 and 5.595, respectively.

Figure 4 Female, 57 years old. The pathological diagnosis is poorly differentiated adenocarcinoma. The lesion invades the subserosa of the lesser curvature of the stomach and is determined to be T3 stage. (A) ROI was manually drawn on whole lesions in late arterial phase. Corresponding parametric maps of Ktrans (B), Kep (C) and Ve (D) are created automatically. The corresponding mean values of Ktrans, Kep and Ve are 0.818 /min, 1.298 /min and 0.551, respectively. The histogram of tumor (E) demonstrates that the skewness, kurtosis and entropy are -0.030, 0.139 and 6.003, respectively.

Figure 5 Male, 51 years old. The pathological diagnosis is adenocarcinoma. The lesion invades the serosal layer of the lesser curvature of the stomach and is determined to be T4a stage. (A) ROI was manually drawn on whole lesions in late arterial phase. Corresponding parametric maps of Ktrans (B), Kep (C) and Ve (D) are created automatically. The corresponding mean values of Ktrans, Kep and Ve are 0.159 /min, 0.117 /min and 0.327, respectively. The histogram of tumor (E) demonstrates that the skewness, kurtosis and entropy are 0.012, -0.142 and 6.104, respectively.

Table 1 The Clinicopathological Characteristics of Gastric Cancer

Clinicopathological Characteristics	Total (n=78) (Proportion)
Age (years, mean±SD)	62.5±12.3
Gender
Male	58(74.4%)
Female	20(25.6%)
Tumour location
Cardia	42(53.8%)
Corpus or antrum	36(46.2%)
Tumor thickness (mm, mean±SD)	13.2±6.3
T stage*
T1	5(6.4%)
T2	9(11.5%)
T3	50(64.1%)
T4	14(17.9%)
N stage*
N0	42(53.8%)
N1	20(25.6%)
N2	14(17.9%)
N3	2(2.6%)
M stage*
M0	78(100%)
M1	0(0%)

Note: *According to AJCC/UICC TNM Staging of Gastric Cancer (8th Edition).

Table 2 The Consistency Analysis of Quantitative DCE Parameters and Histogram Metrics Results Measured by Two Radiologists

	Radiologist 1	Radiologist 2	ICC (95% Confidence Interval)	P
K^trans(/min)	0.43±0.25	0.40±0.36	0.792 (0.711,0.853)	<0.001*
Kep(/min)	0.65±0.48	0.58±0.37
Ve	0.50±0.18	0.43±0.22
Skewness	0.01±0.40	−0.01±0.39
Kurtosis	−0.13±0.58	−0.11±0.72
Entropy	5.63±0.85	5.73±1.03

Notes: The data were expressed as mean and standard deviation; *P<0.0.5.

Abbreviation: ICC, Intraclass correlation coefficient.

Table 3 Quantitative DCE Parameters to Evaluate T and N Staging

		K^trans (/min)	χ^2	P	Kep (/min)	χ^2	P	Ve	F(χ^2)	P
T stage	T1+2 (n=14)	0.27±0.18	8.336	0.015*	0.41±0.45	6.838	0.033*	0.33±0.21	9.188	<0.001*
	T3 (n=50)	0.46±0.26			0.69±0.48			0.52±0.16
	T4 (n=14)	0.47±0.26			0.75±0.47			0.59±0.15
N stage	N0 (n=42)	0.39±0.24	3.539	0.170	0.61±0.48	1.617	0.446	0.47±0.19	χ^2=6.373	0.041*
	N1 (n=20)	0.41±0.26			0.63±0.47			0.49±0.17
	N2+3 (n=16)	0.53±0.27			0.79±0.49			0.61±0.14

Notes: The data were expressed as mean and standard deviation; Pairwise comparison: In Ve, T1+2 and T3 group (P<0.001*), T1+2 and T4 group (P<0.001*) were statistically significant; *P<0.0.5.

Table 4 Histogram Metrics to Evaluate T and N Staging

		Skewness	F	P	Kurtosis	χ^2(F)	P	Entropy	χ^2	P
T stage	T1+2 (n=14)	0.17±0.57	1.608	0.207	−0.14±0.55	1.106	0.575	4.79±1.52	10.029	0.007*
	T3 (n=50)	−0.00±0.34			−0.17±0.60			5.77±0.48
	T4 (n=14)	−0.09±0.38			−0.01±0.55			5.98±0.35
N stage	N0 (n=42)	0.02±0.42	0.029	0.972	−0.19±0.46	F=0.624	0.538	5.45±1.06	5.982	0.050
	N1 (n=20)	0.01±0.35			−0.11±0.80			5.79±0.31
	N2+3 (n=16)	−0.00±0.41			−0.01±0.57			5.92±0.55

Notes: The data were expressed as mean and standard deviation; *P<0.0.5.

Table 5 Diagnostic Performance of Whole Tumor Histogram Analysis Parameters Derived from DCE-MRI for Discriminating T and N Staging

		AUC (95% Confidence Interval)	Cutoff value	Sensitivity	Specificity	P
T stage	K^trans (/min)	0.747 (0.6018, 0.892)	0.29/min	0.786	0.703	0.004*
	Kep (/min)	0.722 (0.554, 0.890)	0.32/min	0.571	0.844	0.010*
	Ve	0.788 (0.643, 0.932)	0.52	0.929	0.578	0.001*
	Entropy	0.740 (0.579, 0.901)	5.62	0.714	0.766	0.005*
N stage	Ve	0.590 (0.463, 0.716)	0.38	0.714	0.889	0.173

Note: *P<0.0.5.