Reliability of ADC histogram analysis
All ADC values (ADCmax, ADCmean, and ADCmin) measured by the two radiologists for EC patients showed excellent consistency, using intraclass correlation coefficients to evaluate (all ICC > 0.80).
Clinical and pathological features of EC
A total of 105 patients aged 48.88 ± 4.68 years (mean age 48 years, minimum age 26 years, and maximum age 55 years) with EC were included in this study. There were 85 cases of stage I, 14 cases of stage II, 5 cases of stage III, and 1 case of stage IV EC according to the FIGO classification. The pathological grades comprised 52 grade I cases, 45 grade II cases, and 7 grade III cases. Among the pathological types, there were 101 cases of adenocarcinoma, 1 case of plasmacytoma, 1 case of mucinous adenocarcinoma, and 2 cases of clear cell carcinoma. The tumor size was 2.90 ± 1.46 cm; BMI was 25.59 ± 5.66 kg/m2; preoperative albumin level was 43.93 ± 4.41 g/L; and CA125 level was 24.75 ± 28.83 U/mL.
The clinical profile and pathological characteristics of EC patients, such as age and pathological grading, did not correlate with the myometrial infiltration and Ki-67 and p53 expression levels. There were more patients with myometrial infiltration < 1/2 and Ki67 ≤ 30% in FIGO stage I/II than in FIGO stage III/IV (P < 0.05, Table 2).
Table 2
Variables
|
Data
|
Age (years) *
|
48.88 ± 4.68
|
FIGO stage
|
|
I/II
|
99(94.3%)
|
III/IV
|
6(5.7%)
|
Pathological grade
|
|
I
|
52(50.0%)
|
II
|
45(43.3%)
|
III
|
7(6.7)
|
Pathological type
|
|
Adenocarcinoma
|
101(96.2%)
|
Other
|
4(3.8%)
|
Tumor size (cm) *
|
2.90 ± 1.46
|
BMI (kg/m2) *
|
25.59 ± 5.66
|
Albumin(g/L) *
|
43.93 ± 4.41
|
CA-125(U/mL) *
|
24.75 ± 28.83
|
Note: *is expressed by mean + standard deviation |
FIGO: International Federation of Obstetrics and Gynecology; BMI: Body Mass Index; CA-125: Carbohydrate antigen-125. |
FIGO: International Federation of Obstetrics and Gynecology; BMI: Body Mass Index; CA-125: Carbohydrate antigen-125.
ADC value and pathological features of EC
The ADCmax (0.79 [0.61, 1.01] vs. 0.64 [0.47, 0.77]), ADCmean (0.75 [0.52, 0.95] vs. 0.58 [0.40–0.66]), and ADCmin (0.71 [0.50–0.89] vs. 0.49 [0.37–0.63]) values in the myometrial infiltration < 1/2 group were all greater than in the myometrial infiltration > 1/2 group (P < 0.05). The ADCmax (0.99 ± 0.30 vs. 0.63 ± 0.19), ADCmean (0.93 ± 0.31 vs. 0.58 ± 0.18), and ADCmin (0.87 ± 0.33 vs. 0.54 ± 0.20) values were greater in the low expression Ki-67 than in the high expression group (P < 0.05). The ADCmax (0.88 ± 0.36 vs. 0.75 ± 0.27), ADCmean (0.35 ± 0.63 vs. 0.27 ± 0.31), and ADCmin (0.80 ± 0.35 vs. 0.63 ± 0.27) values were greater in the p53-negative group than in the p53-positive group (P < 0.05) (Table 3).
Table 3
Comparison of the clinical profile and pathological features of the EC
Variable
|
MI < 1/2
(n = 87)
|
MI > 1/2
(n = 18)
|
P-Value
|
Ki67 ≤ 30%
(n = 45)
|
Ki67 > 30%
(n = 60)
|
P-Value
|
p53(-)
(n = 31)
|
p53(+)
(n = 74)
|
P-Value
|
Age(years)
|
50.00(47.00, 52.00)
|
50.50(43.75, 52.00)
|
0.973
|
49.00(46.50, 52.00)
|
50.00(47.00, 52.00)
|
0.198
|
50(47.00, 52.00)
|
50(47.00, 52.00)
|
0.604
|
FIGO stage
|
|
|
0.008
|
|
|
0.036
|
|
|
0.357
|
I/II
|
85((97.7%)
|
14(77.8%)
|
|
45(100%)
|
54(90.0%)
|
|
28(90.3%)
|
71(95.9%)
|
|
III/IV
|
2(2.3%)
|
4(22.2%)
|
|
0
|
6(10%)
|
|
3(9.7%)
|
3(4.1%)
|
|
Pathological grade
|
|
|
0.079
|
|
|
0.077
|
|
|
0.196
|
I
|
46(53.5%)
|
6(33.3%)
|
|
28(63.6%)
|
24(40.0%)
|
|
16(51.6%)
|
36(49.3%)
|
|
II
|
36(41.9%)
|
9(50.0%)
|
|
14(31.8%)
|
31(51.7)
|
|
15(48.4%)
|
30(41.1%)
|
|
III
|
4(4.7%)
|
3(16.7%)
|
|
2(4.5%)
|
5(8.3)
|
|
0
|
7(9.6%)
|
|
Pathological type
|
|
|
0.135
|
|
|
0.633
|
|
|
1
|
Adenocarcinoma
|
85(97.7%)
|
16(88.9%)
|
|
44(97.8%)
|
57(95.0%)
|
|
30(96.8%)
|
71(95.9%)
|
|
Other
|
2(2.3%)
|
2(11.1%)
|
|
1(2.2%)
|
3(5.0%)
|
|
1(3.2%)
|
3(4.1%)
|
|
BMI (kg/m2)
|
24.89(22.48, 27.05)
|
25.32(22.89, 29.07)
|
0.465
|
25.20(22.32, 27.34)
|
24.09(22.93, 27.06)
|
0.681
|
25.20(23.51, 27.34)
|
24.59(22.46, 27.06)
|
0.560
|
CA-125(U/mL)
|
18.94(13.20, 26.44)
|
21.63(12.48, 33.99)
|
0.344
|
19.90(15.33, 12.93)
|
18.28(12.93, 26.28)
|
0.296
|
19.90(17.79, 27.22)
|
18.13(12.38, 27.90)
|
0.205
|
Tumor size(cm)
|
2.70(2.00, 3.00)
|
3.00(2.00, 4.55)
|
0.098
|
2.50(2.00, 3.00)
|
3.00(2.00, 3.50)
|
0.093
|
3.00(2.30, 3.00)
|
2.60(2.00-3.50)
|
0.395
|
Albumin(g/L)
|
44.40(41.20, 48.88)
|
43.95(40.10, 47.08)
|
0.922
|
42.50(40.80, 45.60)
|
44.40(41.73, 49.70)
|
0.217
|
44.50(41.70, 46.60)
|
43.90(40.80-46.87)
|
0.792
|
ADCmax (10− 3mm2 /s)
|
0.79(0.61, 1.01)
|
0.64(0.47, 0.77)
|
0.005
|
0.99 ± 0.30
|
0.63 ± 0.19
|
< 0.001
|
0.88 ± 0.36
|
0.75 ± 0.27
|
0.045
|
ADCmean (10− 3mm2 /s)
|
0.75(0.52, 0.95)
|
0.58(0.40, 0.66)
|
0.009
|
0.93 ± 0.31
|
0.58 ± 0.18
|
< 0.001
|
0.35 ± 0.63
|
0.27 ± 0.31
|
0.015
|
ADCmin (10− 3mm2 /s)
|
0.71(0.50, 0.89)
|
0.49(0.37, 0.63)
|
0.009
|
0.87 ± 0.33
|
0.54 ± 0.20
|
< 0.001
|
0.80 ± 0.35
|
0.63 ± 0.27
|
0.006
|
FIGO: International Federation of Obstetrics and Gynecology; BMI: Body Mass Index; CA-125: Carbohydrate antigen-125; MI: Myometrial infiltration |
Nomogram development and validation
The AUC values of the ADCmax, ADCmean, and ADCmin values and FIGO stage to predict myometrial infiltration were 0.707 (0.587–0.827), 0.693 (0.572–0.813), 0.694 (0.571–0.817), and 0.599 (0.499–0.700), with specificities of 72.2%, 83.3%, 83.3% and 66.7% and sensitivities of 64.0%, 60.5%, 59.3% and 85.9%, respectively. By combining the ADCmax, ADCmean, and ADCmin values and FIGO stages, a nomogram model was constructed to predict myometrial infiltration in EC patients. Its diagnostic efficacy was than that of the previous model. The AUC value was 0.809 (0.698–0.920), with a specificity of 83.3% and sensitivity of 72.1% (Fig. 3) (Table 4 and Fig. 4A, D).
The AUC values for predicting the Ki-67 expression level by ADCmax, ADCmean, and ADCmin values and FIGO stage were 0.879 (0.801–0.956), 0.849 (0.768–0.931), 0.808 (0.718–0.898) and 0.550 (0.512–0.588), with specificities of 90.0%, 86.7%, 91.7%, and 45.5% and sensitivities of 84.1%, 75.0%, 63.6%, and 100%, respectively. The nomogram model for predicting the Ki-67 expression level in EC patients was constructed by combining the ADCmax, ADCmean, and ADCmin values and FIGO stage. Its diagnostic efficacy was higher than that of the previous model. The AUC value was 0.897 (0.831–0.962), with a specificity of 95.0% and sensitivity of 75.0% (Table 4 and Fig. 4B, E).
The AUC values of ADCmax, ADCmean, and ADCmin to predict the p53 expression levels were 0.615 (0.491–0.739), 0.641 (0.519–0.762) and 0.654 (0.538–0.771), with specificities of 75.7%, 55.4%, and 56.8% and sensitivities of 48.4%, 77.4%, and 77.4%, respectively. The nomogram model for predicting the p53 expression level in EC patients was constructed by combining the ADCmax, ADCmean, and ADCmin values. Its diagnostic efficacy was also higher than that of the previous model. The AUC value was 0.665 (0.556–0.774), with a specificity of 67.6% and sensitivity of 64.5% (Table 4, Fig. 4C, F).
The calibration curve was used to evaluate the nomogram model (1000 internal validations of bootstrap resampling were performed), and the results showed that the nomogram model based on the ADC values was highly calibrated (Fig. 5).
Table 4
Diagnostic effectiveness of different models
|
|
AUC (95%CI)
|
Cutoff value
|
Specificity(%)
|
Sensitivity (%)
|
MI
|
Nomogram
|
0.809(0.698–0.920)
|
107.95
|
83.3
|
72.1
|
|
ADCmax
|
0.707(0.587–0.827)
|
0.69(10 − 3 mm2 /s)
|
72.2
|
64.0
|
|
ADCmean
|
0.693(0.572–0.813)
|
0.67(10 − 3 mm2 /s)
|
83.3
|
60.5
|
|
ADCmin
|
0.694(0.571–0.817)
|
0.65(10 − 3 mm2 /s)
|
83.3
|
59.3
|
|
FIGO
|
0.599(0.499-0.700)
|
0
|
66.7
|
85.9
|
Ki-67
|
Nomogram
|
0.897(0.831–0.962)
|
88.01
|
95.0
|
75.0
|
|
ADCmax
|
0.879(0.801–0.956)
|
0.79(10 − 3 mm2 /s)
|
90.0
|
84.1
|
|
ADCmean
|
0.849(0.768–0.931)
|
0.77(10 − 3 mm2 /s)
|
86.7
|
75.0
|
|
ADCmin
|
0.808(0.718–0.898)
|
0.79(10 − 3 mm2 /s)
|
91.7
|
63.6
|
|
FIGO
|
0.550(0.512–0.588)
|
0
|
45.5
|
100
|
P53
|
Nomogram
|
0.665(0.556–0.774)
|
111.94
|
67.6
|
64.5
|
|
ADCmax
|
0.615(0.491–0.739)
|
0.86(10 − 3 mm2 /s)
|
75.7
|
48.4
|
|
ADCmean
|
0.641(0.519–0.762)
|
0.66(10 − 3 mm2 /s)
|
55.4
|
77.4
|
|
ADCmin
|
0.654(0.538–0.771)
|
0.64(10 − 3 mm2 /s)
|
56.8
|
77.4
|
FIGO: International Federation of Obstetrics and Gynecology; MI: Myometrial infiltration; |