Patient Demographics
A total of 85 patients with 22 SMBTs, 42 CCCs and 21 ECs were enrolled. Clinical features of patients with SMBT and CCC/EC are summarized in Table 2. There were significant differences of ages among three groups of patients (p < 0.001). Thereinto, patients with SMBT were significantly younger (39.91 ± 12.08 years) than patients with CCC (51.48 ± 9.52 years) and EC (52.24 ± 8.15 years) (both p < 0.001). There was no significant difference between patients with CCC and EC (p = 1.000). Most patients with SMBT, CCC and EC were at early stage (stage I and II) and all the patients had a unilateral tumor. No significant differences were observed in the FIGO stage and laterality among three groups (p = 0.312, 0.722, respectively).
Table2. Clinical features of patients with SMBT, CCC and EC
Features
|
SMBT (n = 22)
|
CCC (n = 42)
|
EC (n = 21)
|
p value
|
Age (mean, y)
|
39.91 ± 12.08$₤
|
51.48 ± 9.52$
|
52.24 ± 8.15₤
|
< 0.001*
|
Laterality
|
|
|
|
0.722#
|
Right
|
14
|
23
|
11
|
|
Left
|
8
|
19
|
10
|
|
FIGO stage
|
|
|
|
0.312§
|
I
|
18
|
41
|
16
|
|
II
|
2
|
0
|
5
|
|
III
|
2
|
1
|
0
|
|
IV
|
0
|
0
|
0
|
|
FIGO, International Federation of Gynecology and Obstetrics. * One-way ANOVA; # Chi-square test; § Fisher's precision probability test (FIGO I+II vs III+IV); $, ₤ There was significant difference between the two groups.
Solid component ADC (ADCSC) and whole-tumor ADC histogram parameters
The intra- and interobserver agreement was excellent for the ADCSC and histogram parameters, with ICCs of 0.961 (95% confidence interval (CI), 0.941, 0.974) and 0.980 (95% CI, 0.970, 0.987), respectively. The results of the first measurement by radiologist 1 were used for further analyses.
There were significant differences in the ADCSC and whole-tumor histogram parameters including the volume, ADCmean, the 10th, 50th and 90th percentile ADCs among three kinds of tumors (all p < 0.01) (Table 3). The ADCSC was significantly higher in SMBT than in CCC and EC (both p < 0.001), but was no significant difference between CCC and EC (p = 0.328). The volume was significantly smaller in SMBT than in CCC (p < 0.001) and EC (p = 0.024), but was no significant difference between CCC and EC (p = 0.559). The ADCmean was significantly higher in CCC than in EC (p < 0.001), but were no significant differences between SMBT and CCC/EC (p = 0.050 and 0.418, respectively). The 10th percentile ADC was significantly lower in EC than in SMBT (p = 0.033) and CCC (p = 0.011), but was no significant difference between SMBT and CCC (p = 1.000). The 50th and 90th percentile ADCs were significantly higher in CCC than in SMBT and EC (p = 0.015, p < 0.001 and both p < 0.001, respectively), but were no significant differences between SMBT and EC (p = 0.814 and 1.000, respectively). There were no significant differences found in other histogram-derived parameters including the skewness, kurtosis, inhomogeneity or entropy among three tumors.
Table3. ADC of solid components and whole-tumor ADC histogram parameters in SMBT, CCC and EC
Parameters
|
SMBT (n = 22)
|
CCC (n = 42)
|
EC (n = 21)
|
p value
|
ADCsc*
|
1.8 (1.7, 1.9)$ ₤
|
1.2 (1.0, 1.4)$
|
1.0 (1.0, 1.2)₤
|
< 0.001
|
Whole-tumor ADC histogram parameters
|
|
|
|
|
Volume (cm3)
|
187.6 (76.0, 249.9)$ ₤
|
537.0 (338.9, 822.0)$
|
280.1 (140.3, 1022.2)₤
|
< 0.001
|
ADCmean*
|
2.0 ± 0.4
|
2.2 ± 0.3&
|
1.9 ± 0.3&
|
< 0.001
|
10th percentile ADC*
|
1.8 (1.5, 2.0)₤
|
1.7 (1.3, 2.2)&
|
1.2 (1.0, 1.5)₤ &
|
0.008
|
50th percentile ADC*
|
2.1 (1.7, 2.3)$
|
2.5 (2.2, 2.6)$ &
|
1.9 (1.6, 2.2)&
|
< 0.001
|
90th percentile ADC*
|
2.4 (2.0, 2.6)$
|
2.7 (2.5, 2.8)$ &
|
2.4 (2.1, 2.6)&
|
< 0.001
|
Skewness
|
-0.5 ± 1.4
|
-1.2 ± 1.2
|
-0.7 ± 1.0
|
0.055
|
Kurtosis
|
3.1 (2.4, 6.2)
|
2.6 (-0.5, 7.6)
|
1.4 (-0.9, 4.8)
|
0.104
|
Inhomogeneity
|
0.1 (0.1, 0.1)
|
0.2 (0.1, 0.2)
|
0.1 (0.1, 0.2)
|
0.052
|
Entropy
|
3.5 ± 0.4
|
3.6 ± 0.5
|
3.8 ± 0.5
|
0.115
|
ADC, apparent diffusion coefficient; ADCsc, solid component ADC; p value, One-way ANOVA or Kruskal-Wallis. * ×10-3 mm2/s; $, ₤, & There was significant difference between the two groups.
For differentiating SMBT from CCC, AUCs of the ADCSC, volume, the 50th and 90th percentile ADCs were 0.97, 0.86, 0.72 and 0.81, respectively, with a significant difference between ADCSC and the 50th percentile ADC (p = 0.003) (Table 4, Fig 2); and no significant differences between ADCSC and volume, or 90th percentile ADC (p = 0.097 and 0.053, respectively). For differentiating SMBT from EC, the ADCSC had a significantly larger AUC than the volume and 10th percentile ADC (0.97 vs 0.71 and 0.72, p = 0.003 and 0.015, respectively). For differentiating CCC from EC, the ADCmean, the 10th, 50th and 90th percentile ADCs had AUCs of 0.79, 0.72, 0.81 and 0.85, without significant AUC differences among the four histogram-derived parameters (all p > 0.05).
Table 4. Diagnostic performance of ADC of solid components and whole-tumor histogram parameters in differentiating SMBT, CCC and EC
Parameters
|
SMBT vs CCC
|
SMBT vs EC
|
CCC vs EC
|
AUC
|
Sensitivity (%)
|
Specificity (%)
|
Cutoff value
|
AUC
|
Sensitivity (%)
|
Specificity (%)
|
Cutoff value
|
AUC
|
Sensitivity (%)
|
Specificity (%)
|
Cutoff value
|
ADCsc*
|
0.97$
|
94.1
|
94.9
|
1.5
|
0.97$ ₤
|
94.1
|
94.4
|
1.5
|
-
|
-
|
-
|
-
|
Volume (cm3)
|
0.86
|
77.3
|
88.1
|
237.1
|
0.71$
|
77.3
|
66.7
|
237.1
|
-
|
-
|
-
|
-
|
ADCmean*
|
-
|
-
|
-
|
-
|
-
|
-
|
-
|
-
|
0.79
|
76.2
|
76.2
|
2.0
|
10th percentile ADC*
|
-
|
-
|
-
|
-
|
0.72₤
|
77.3
|
76.2
|
1.5
|
0.72
|
85.7
|
52.4
|
1.2
|
50th percentile ADC*
|
0.72$
|
77.3
|
69.1
|
2.2
|
-
|
-
|
-
|
-
|
0.81
|
61.9
|
95.2
|
2.4
|
90th percentile ADC*
|
0.81
|
68.2
|
88.1
|
2.5
|
-
|
-
|
-
|
-
|
0.85
|
73.8
|
90.5
|
2.6
|
AUC, area under the curve.
*, ×10-3 mm2/s; $, ₤ There was significant difference in AUC between the two parameters.