An overview of the investigated patient sample is provided by Table 1. Patients with long-time survival were being followed-up without signs of tumor recurrence for a mean time of 33.3 ± 20.3 months (ranging from 8 to 61 months).
Table 1
Overview of the descriptive statistics of the included patient sample.
| Survivors (n = 10) | Non-survivors (n = 12) | p-value |
Gender (female, %) | 5 (50) | 5 (42) | 0.77 |
Age, years | 71.90 ± 7.40 | 71.67 ± 10.07 | 0.87 |
Bismuth classification | | | 0.82 |
I | 0 | 0 | |
II | 0 | 1 | |
IIIA | 1 | 0 | |
IIIB | 0 | 1 | |
IV | 9 | 10 | |
Grading | | | |
I | 0 | 1 | |
II | 8 | 9 | |
III | 2 | 2 | |
pT | | | 0.08 |
pT1a | 0 | 1 | |
pT1b | 0 | 2 | |
pT2a | 2 | 5 | |
pT2b | 6 | 2 | |
pT3 | 1 | 1 | |
pT4 | 1 | 1 | |
N | | | 0.38 |
N0 | 5 | 8 | |
N1 | 3 | 4 | |
N2 | 2 | 0 | |
M | | | 0.77 |
M0 | 10 | 11 | |
M1 | 0 | 1 | |
Preoperative Bilirubine (µmol/l) | 11.15 ± 3.18 | 34.58 ± 16.78 | 0.03 |
Preoperative Quick (%) | 86.50 ± 20.51 | 86.83 ± 16.69 | 0.92 |
Preoperative CEA | 1.91 ± 0.46 | 4.67 ± 5.99 | 0.83 |
Preoperative CA 19 − 9 | 111.50 ± 38.89 | 221.10 ± 163.44 | 0.66 |
Preoperative AFP | 2.43 ± 0.86 | 10.29 ± 17.76 | 0.29 |
3.1 Discrimination analysis of survival
In discrimination analysis for clinical outcome, the following CT texture frautes were statistically different between 30-day mortality and survival: S(0,1)SumOfSqs (30-day-survival: 108.74 ± 3.88 vs. Non-survival: 102.99 ± 3.04, p = 0.035), S(1,1)SumOfSqs (109.05 ± 4.02 vs. 102.07 ± 1.89, p = 0.02), S(1,1)InvDfMom (0.09 ± 0.02 vs. 0.11 ± 0.01, p = 0.04), S(4,0)Contrast (220.50 ± 27.47 vs. 182.06 ± 4.81, p = 0.04), S(5,0)SumOfSqs (110.26 ± 6.11 vs. 98.90 ± 1.15, p = 0.01), S(5,0)InvDfMom (0.07 ± 0.02 vs. 0.12 ± 0.03, p = 0.04).
Regarding long-term survival, the following texture parameters showed statistical significances: S(1,1)Contrast (survival: 160.84 ± 32.25 vs. non-survival: 191.56 ± 22.83, p = 0.02), S(1,1)SumOfSqs (109.16 ± 3.24 vs. 107.80 ± 5.17, p = 0.01), S(1,1)SumVarnc (275.80 ± 32.57 vs. 239.65 ± 26.03, p = 0.01) (as shown in Fig. 2), S(1,1)DifVarnc (58.18 ± 11.89 vs. 71.45 ± 12.28, p = 0.04), S(2,2)Correlat (0.12 ± 0.15 vs. 0.002 ± 0.07, p = 0.03), S(2,2)SumOfSqs (111.01 ± 4.38 vs. 105.13 ± 5.53, p = 0.01), S(2,2)SumVarnc (247.75 ± 32.07 vs. 210.38 ± 13.16, p = 0.002), S(0,4)InvDfMom (0.08 ± 0.02 vs. 0.07 ± 0.02, p = 0.04), S(0,4)DifVarnc (85.51 ± 17.05 vs. 70.31 ± 13.70, p = 0.04), S(4,4)SumOfSqs (95.30 ± 17.48 vs. 109.68 ± 8.65, p = 0.01), S(5,5)SumOfSqs (86.66 ± 32.61 vs. 110.18 ± 13.48, p = 0.03), S(5,5)SumAverg (62.33 ± 3.09 vs. 66.00 ± 3.62, p = 0.02), S(5,5)DifVarnc (62.96 ± 27.61 vs. 96.72 ± 24.23, p = 0.01), Teta2 (-0.27 ± 0.08 vs. -0.17 ± 0.12, p = 0.01).
3.2 Correlation with tumormarkers
There were moderate statistical significant correlations between several texture features with the tumormarker CEA with Spearman’s correlation coefficients of 0.5 and above:
Skewness (r=-0.66, p = 0.01), S(0,1)DifEntrp (r=-0.611, p = 0.03), S(0,2)DifEntrp (r=-0.655, p = 0.02), S(2,-2)DifVarnc (r=-0.564, p = 0.04), S(3,3)Correlat (r = 0.567, p = 0.04), S(3,3)SumVarnc (r = 0.564, p = 0.04), S(4,-4)InvDfMom (r=-0.578, p = 0.04), S(5,5)Contrast (r = 0.572, p = 0.04), S(5,5)Correlat (r=-0.605, p = 0.03), S(5,5)DifVarnc (r = 0.630, p = 0.02), WavEnLH_s-1 (r=-0.677, p = 0.01), WavEnHL_s-2 (r = 0.732, p = 0.004).
The tumormarker CA 19 − 9 showed statistical significant moderate to good correlations for the following texture parameters with Spearman’s correlation coefficients of 0.5 and above:
_MinNorm (r = 0.543, p = 0.04), S(0,1)InvDfMom (r=-0.66, p = 0.01), S(1,-1)SumVarnc (r=-0.648, p = 0.01), S(1,-1)DifVarnc (r = 0.587, p = 0.03), S(1,-1)DifEntrp (r = 0.591, p = 0.03), S(3,0)SumAverg (r = 0.547, p = 0.04), Vertl_LngREmph (r=-0.560, p = 0.04), Sigma (r = 0.697, p = 0.01, as shown in Fig. 3).
There were strong statistically significant correlations between texture features and the tumormarker AFP with Spearman’s correlation coefficients of 0.75 and above:
S(0,1)AngScMom (r = 0.874, p = 0.005), S(0,1)Entropy (r=-0.838, p = 0.01), S(2,0)Entropy (r=-0.755, p = 0.03), S(0,2)AngScMom (r = 0.838, p = 0.01), S(2,-2)AngScMom (r = 0.778, p = 0.02), S(0,4)SumVarnc (r = 0.790, p = 0.02), S(4,4)AngScMom (r = 0.755, p = 0.03), S(4,4)DifVarnc (r = 0.766, p = 0.03), S(4,-4)AngScMom (r = 0.778, p = 0.02), S(5,-5)SumOfSqs (r=-0.790, p = 0.02).
3.3 Correlation with tumor grading
Correlation of texture parameters with grading showed statistical significant correlation with correlation coefficients of 0.5 and above for:
S(0,1)DifEntrp (r = 0.522, p = 0.01), S(0,2)InvDfMom (r=-0.573, p = 0.01), S(3,0)DifVarnc (r = 0.559, p = 0.01), S(4,0)Contrast (r = 0.508, p = 0.02), S(4,0)DifVarnc (r = 0.568, p = 0.01), S(5,0)SumVarnc (r=-0.587, p = 0.004), S(5,-5)SumAverg (r = 0.519, p = 0.01).
3.4 Correlation with TNM stage
The following texture parameters showed statistical significant corrrelation with T stage with correlation coefficients of 0.5 or above: S(0,5)Contrast (r = 0.527, p = 0.012), S(5,5)DifVarnc (r=-0.499, p = 0.018).
Regarding the N stage texture parameters with N status identified two statistical significant correlations, S(4,-4)Contrast (r = 0.538, p = 0.010), S(4,-4)SumOfSqs (r = 0.579, p = 0.005). There were no statistically significant associations with positive M status.