Textural differences based on apparent diffusion coefficient maps for discriminating pT3 subclasses of rectal adenocarcinoma

Table 1 Demographic and pathologic characteristics of patients

Characteristic	n = 59
Age (yr), median (IQR)	66 (58-74)
Sex
Men	34 (57.6)
Women	25 (42.4)
Differentiation grade
Moderately differentiated	44 (74.6)
Poorly differentiated	15 (25.4)
T3 stage
T3a	30 (50.9)
T3b	24 (40.7)
T3c	5 (8.5)
N stage
N0	27 (45.8)
N1	22 (37.3)
N2	10 (17.0)
M stage
M0	55 (93.2)
M1	4 (6.8)

Except for age, data are expressed as n (%). IQR: Interquartile range.

Table 2 Comparison of apparent diffusion coefficient first-order textural differences between pT3a and pT3b-c stage

ADC histogram feature	pT3a (n = 30)	pT3b-c (n = 29)	P value	ICC
Mean ADC (× 10-6 mm2/s)1	879.5 ± 202.3	832.8 ± 166.7	0.339	0.906
5th ADC (× 10-6 mm2/s)1	584.4 ± 163.3	533.1 ± 111.9	0.164	0.898
10th ADC (× 10-6 mm2/s)1	638.6 ± 164.2	589.5 ± 111.0	0.183	0.901
25th ADC (× 10-6 mm2/s)1	720.2 ± 175.8	664.5 ± 125.7	0.168	0.921
90th ADC (× 10-6 mm2/s)1	1113.8 ± 275.8	1055.7 ± 229.3	0.383	0.850
Skewness1	0.24 ± 0.31	0.41 ± 0.32	0.033	0.925
Kurtosis1	0.66 ± 0.52	0.80 ± 0.70	0.376	0.909
Uniformity1	0.78 ± 0.06	0.76 ± 0.05	0.058	0.921

¹Independent samples t-test, and data are the mean ± SD.

ADC: Apparent diffusion coefficient; ICC: Intraclass correlation coefficient.

Table 3 Comparison of apparent diffusion coefficient textural differences between pT3a and pT3b-c stages

ADC texture feature	pT3a (n = 30)	pT3b-c (n = 29)	P value	ICC
Energy (× 10-3)2	0.782 (0.527, 1.399)	0.640 (0.437, 0.779)	0.038	0.895
Entropy2	9.831 (8.969, 10.652)	10.805 (10.189, 11.592)	0.001	0.920
Inertia1	753.0 ± 417.0	878.9 ± 279.0	0.180	0.918
Correlation (× 10-3)2	0.538 (0.399, 1.255)	0.476 (0.414, 0.642)	0.332	0.921

¹Independent samples t-test, and data are the mean ± SD.

²Mann-Whitney U-test, and data are the median ± interquartile range.

ADC: Apparent diffusion coefficient; ICC: Intra-class correlation coefficient.

Table 4 Diagnostic performances of texture features and logistic feature to discriminate pT3a rectal adenocarcinomas from pT3b-c tumors

Texture features	AUC (95%CI)	Sensitivity	Specificity	+LR	-LR	+PV	-PV	Comparison of AUC (P value)
								Skewness	Energy	Entropy	Logistic feature
Skewness	0.686 (0.552-0.801)	75.9%	63.3%	2.07	0.38	66.7	73.1	—	0.7469	0.4667	0.1471
Energy	0.657 (0.522-0.776)	86.2%	43.3%	1.52	0.32	59.5	76.2		—	0.0956	0.0617
Entropy	0.747 (0.617-0.851)	75.9%	63.3%	2.07	0.38	66.7	73.1			—	0.3998
Logistic feature	0.775 (0.647-0.873)	69.0%	83.3%	4.14	0.37	80.0	73.5				—

AUC: Area under the curve; CI: Confidence interval; LR: Likelihood ratio; PV: Predictive value.