A total of 42 TED patients were enrolled in this study, including 29 patients in analysis group and 13 patients in validation group.In analysis group,the mean age was 47.78 ± 5.15 years. The duration of TED was 19.04 ± 15.49 months. Nine of them were male (31.03%). Five of them were smoker (17.24%).
The clinical characteristics of active and inactive eyes
Fifty-eight eyes of 29 TED patients in analysis group were divided into active(n = 28) and inactive eyes (n = 30) based on CAS. As shown in Table 1, compared with inactive eyes, active eyes had much worse eyesight, higher intraocular pressure and degree of exophthalmos.
Table 1
The clinical characteristics of active and inactive eyes
| Active eyes(n = 28) | Inactive eyes(n = 30) | P-value |
Eyesight | 0.58 ± 0.14 | 0.83 ± 0.10 | 0.010# |
Intraocular pressure(mmHg) | 20.75 ± 1.89 | 17.43 ± 0.77 | 0.002* |
Exophthalmos(mm) | 20.63 ± 1.07 | 18.00 ± 0.99 | 0.001# |
CAS | 3.82 ± 0.33 | 1.17 ± 0.14 | 0.000# |
Data represented as mean ± SD;n: number |
*: the Unpaired t-test;#: Mann-Whitney Test |
P- value < 0.05 was considered to be significant. |
ADC values of each EOM in active and inactive eyes
As shown in Table 2, ADCmean differed between the two groups in IR (1289.45 ± 90.44×10− 6mm2s− 1 vs 1161.18 ± 88.87 ×10− 6mm2s− 1; P = 0.029), not in SR, LR and MR (all p > 0.05). △ADC differed between the two groups in all four EOMs (
Table 2
The ADCmean and △ADC value of each EOM in active and inactive eyes
| Active eyes(n = 28) | Inactive eyes(n = 30) | P-Value |
ADCmean of SR | 1412.21 ± 89.56 | 1508.57 ± 108.62 | 0.170* |
ADCmean of IR | 1289.45 ± 90.44 | 1161.18 ± 88.87 | 0.029# |
ADCmean of MR | 1526.72 ± 80.57 | 1396.41 ± 124.84 | 0.079* |
ADCmean of LR | 1297.67 ± 106.56 | 1256.01 ± 108.15 | 0.577* |
△ADC of SR | 392.18 ± 101.04 | 555.7 ± 80.23 | 0.001# |
△ADC of IR | 581.46 ± 162.67 | 880.77 ± 193.43 | 0.039# |
△ADC of MR | 344.32 ± 78.81 | 476.13 ± 93.04 | 0.032* |
△ADC of LR | 677.39 ± 187.22 | 1154.97 ± 295.04 | 0.011# |
ADCmean: the average ADC value of five planes;SR: Superior rectus;IR: Inferior rectus;MR: Medial rectus;LR: Lateral rectus;n: number |
Data represented as mean ± SD |
*: The Unpaired t-test;#: Mann-Whitney Test |
Q- value < 0.05 was considered to be significant. |
SR: 392.18 ± 101.04×10− 6mm2s-1 vs. 555.7 ± 80.23×10− 6mm2s-1, P = 0.001;
IR: 581.46 ± 162.67×10− 6mm2s-1 vs. 880.77 ± 193.43×10− 6mm2s-1, P = 0.039;
MR : 344.32 ± 78.81×10− 6mm2s-1 vs. 476.13 ± 93.04×10− 6mm2s-1, P = 0.032;
LR: 677.39 ± 187.22×10− 6mm2s-1 vs. 1154.97 ± 295.04×10− 6mm2s-1,P = 0.011).
Correlations between ADC values and CAS
As shown in Table 3, ADCmean of IR showed positive correlation with CAS (P = 0.043,R = 0.27).△ADC showed negative correlation with CAS in SR(P = 0.011, R=-0.330), IR(P = 0.019,R=-0.306), MR(P = 0.032,R=-0.282)and LR(P = 0.008,R=-0.345).
Table 3
The association between ADC values of each EOM and CAS
| r | P-Value |
ADCmean of IR | 0.27 | 0.043 |
△ADC of SR | -0.33 | 0.011 |
△ADC of IR | -0.31 | 0.019 |
△ADC of MR | -0.28 | 0.032 |
△ADC of LR | -0.35 | 0.008 |
EOM: extraocular muscle;CAS: clinical activity score;SR: Superior rectus;IR: Inferior rectus;MR: Medial rectus;LR: Lateral rectus;△ADC: the difference between the maximum and minimum ADC value. |
Pearson correlation test was used to evaluate the correlations. |
P- value < 0.05 was considered to be significant. |
Receiver operating characteristic(ROC)cure analysis
To determine the predictive efficiency and diagnostic cut-off value, we performed ROC curve analysis in Table 4.The cut-off value of ADCmean used to predict active disease was >1259.3×10− 6mm2s− 1 with a sensitivity of 66.7% and a specificity of 71.4% in IR(AUC:0.667,P = 0.029).△ADC performed well in discriminating activity in all four EOMs( SR:AUC = 0.746,P = 0.001; IR:AUC = 0.675,P = 0.022; MR:AUC = 0.658,P = 0.039 and LR:AUC = 0.695,P = 0.011).The cut-off value of △ADC were >382×10− 6mm2s− 1 in SR,>823×10− 6mm2s− 1 in IR,>520×10− 6mm2s− 1 in MR and >572×10− 6mm2s− 1 in LR.And the sensitivity were 80.0%, 50.0%,43.3%,83.3% and the specificity were 67.9%,85.7%,89.3%,60.7% in SR,IR, MR, and LR respectively.
Table 4
Predictive performance of ADC values of each EOM between the active and inactive eyes
| AUC | Cut-off | Sensitivity % | Sensitivity % | P-value | Validation of Cut-offs |
| Sensitivity% | Specificity% |
ADCmean of IR | 0.667 | 1259.3 | 66.70 | 71.4 | 0.029 | 68.42 | 57.14 |
△ADC of SR | 0.746 | 382.00 | 80.00 | 67.90 | 0.001 | 68.42 | 71.43 |
△ADC of IR | 0.675 | 823.00 | 50.00 | 85.70 | 0.022 | 63.16 | 57.14 |
△ADC of MR | 0.658 | 520.00 | 43.30 | 89.30 | 0.039 | 68.42 | 57.14 |
△ADC of LR | 0.695 | 572.00 | 83.30 | 60.70 | 0.011 | 68.42 | 85.71 |
AUC: Area under curve;EOM: extraocular muscle;△ADC: the difference between the maximum and minimum ADC value;SR: Superior rectus;IR: Inferior rectus;MR: Medial rectus;LR: Lateral rectus.P value < 0.05 was considered to be significant. |
The diagnostic accuracy of the identified cut-off values was further validated in validation group in Table 4 (n = 26). Twenty-six eyes were classified into active and inactive group according to the identified cut-offs and matched with their actual CAS. The diagnostic sensitivity and specificity for the cut-off of ADCmean of IR was 68.42% and 57.14%.The diagnostic sensitivity and specificity for the cut-off of △ADC were 68.42%, 63.16%, 68.42%, 68.42% and 71.43%,57.14%,57.14%,85.71% in SR,IR,MR, and LR respectively.
The predictive efficacy between different △ADC values
To find the best predictor, the predictive efficacy of different ADC were compared in Table 5. There were no significant differences in the predictive efficacy of △ADC cut-off values among SR, IR, MR, LR (all P > 0.05).Also there were no significant differences in the predictive efficacy between ADCmean of IR and △ADC cut-off values (all P > 0.05).
Table 5
The predictive efficacy between different ADC values
| △ADC | ADCmean of IR vs △ADC of each EOM |
| SR vs IR | SR vs MR | SR vs LR | IR vs MR | IR vs LR | MR vs LR | IR vs SR | IR vs IR | IR vs MR | IR vs LR |
P-value | 0.416 | 0.367 | 0.514 | 0.840 | 0.835 | 0.350 | 0.374 | 0.927 | 0.929 | 0.794 |
△ADC: the difference between the maximum and minimum ADC value;SR: Superior rectus;IR: Inferior rectus;MR: Medial rectus;LR: Lateral rectus. |
Delong’s test was used to evaluate the predictive efficacy between different △ADC. |
P-value < 0.05 was considered to be significant. |