Noninvasive prediction of microsatellite instability in stage II/III rectal cancer using dynamic contrast-enhanced magnetic resonance imaging radiomics

Table 1 Baseline characteristics of the study cohort, mean ± SD/n (%)

Characteristic	MSI-H (n = 30)	MSS/MSI-L (n = 90)	P value
Age (years)	61.8 ± 11.9	62.5 ± 12.6	0.452
Age (years), range	37-84	35-85
Gender
Male	20 (66.7)	58 (64.4)	0.678
Female	10 (33.3)	32 (35.6)
Tumor location
Mid-rectum	15 (50)	45 (50)	0.543
Lower rectum	10 (33.3)	30 (33.3)
Upper rectum	5 (16.7)	15 (16.7)
Clinical stage
Stage II	12 (40)	38 (42.2)	0.789
Stage III	18 (60)	52 (57.8)
Tumor size (cm)	4.1 ± 1.6	4.2 ± 1.4	0.612
Tumor size (cm), range	2.0-7.0	2.0-7.5
Lymph node metastasis
Present	15 (50)	45 (50)	0.987
Absent	15 (50)	45 (50)
Histological type
Adenocarcinoma	28 (93.3)	84 (93.3)	0.992

MSI-H: Microsatellite instability-high; MSS: Microsatellite stability; MSI-L: Microsatellite instability-low.

Table 2 Textural features and tumor heterogeneity, mean ± SD

Feature	MSI-H (n = 30)	MSS/MSI-L (n = 90)	P value
Entropy	7.84 ± 0.92	6.39 ± 0.83	0.004
Uniformity	0.17 ± 0.05	0.26 ± 0.07	0.003
Contrast	223.6 ± 48.3	175.2 ± 39.5	0.007
Dissimilarity	12.8 ± 2.6	9.4 ± 2.1	0.005
Homogeneity	0.42 ± 0.08	0.55 ± 0.09	< 0.001
Energy	0.08 ± 0.02	0.12 ± 0.03	< 0.001
Correlation	0.35 ± 0.10	0.50 ± 0.12	< 0.001
ASM	0.06 ± 0.01	0.09 ± 0.02	< 0.001

ASM: Angular second moment; MSI-H: Microsatellite instability-high; MSS: Microsatellite stability; MSI-L: Microsatellite instability-low.

Table 3 Morphological and shape-based radiomics features, mean ± SD

Feature	MSI-H (n = 30)	MSS/MSI-L (n = 90)	P value
Surface-to-volume ratio	0.72 ± 0.14	0.58 ± 0.11	0.008
Sphericity	0.68 ± 0.09	0.79 ± 0.08	0.006
Fractal dimension	1.28 ± 0.07	1.19 ± 0.06	0.009
Maximum 3D diameter (cm)	5.8 ± 1.2	4.9 ± 1.0	0.011
Border irregularity	0.85 ± 0.12	0.68 ± 0.10	0.004
Major axis length (cm)	6.2 ± 1.3	5.3 ± 1.1	0.012
Minor axis length (cm)	3.8 ± 0.9	4.2 ± 0.8	0.035
Least axis length (cm)	2.9 ± 0.7	3.5 ± 0.6	0.021
Surface area (cm2)	125.4 ± 25.6	108.7 ± 20.3	0.007
Flatness	0.45 ± 0.08	0.58 ± 0.07	0.002
Elongation	0.72 ± 0.10	0.64 ± 0.09	0.015

MSI-H: Microsatellite instability-high; MSS: Microsatellite stability; MSI-L: Microsatellite instability-low.

Table 4 First-order statistical features and signal intensity characteristics, mean ± SD

Feature	MSI-H (n = 30)	MSS/MSI-L (n = 90)	P value
Signal intensity variance	3642 ± 782	2815 ± 645	0.007
Kurtosis	4.86 ± 1.12	3.53 ± 0.98	0.005
Skewness	0.89 ± 0.28	0.42 ± 0.19	0.003
Mean signal intensity	785.3 ± 134.2	693.6 ± 128.7	0.009
Peak enhancement (%)	43.7 ± 8.9	35.2 ± 7.4	0.006
Minimum signal intensity	220.5 ± 45.6	250.3 ± 48.9	0.021
Maximum signal intensity	1350.7 ± 210.4	1200.3 ± 180.5	0.013
Signal intensity range	1130.2 ± 190.8	950.0 ± 160.2	0.004
Median signal intensity	750.4 ± 120.3	680.2 ± 110.5	0.011
Standard deviation	300.5 ± 50.2	250.3 ± 45.6	0.008

MSI-H: Microsatellite instability-high; MSS: Microsatellite stability; MSI-L: Microsatellite instability-low.