3.1 Statistical analysis of lesion areas on DR and DN images computed by the Traditional Calculation Method (TCM) and Convolutional Neural Network (CNN)
In this paper, we used two statistical methods of TCM and CNN to evaluate the lesion area of DR and DN in different stages(Fig. 2 and Fig. 3). The average lesion area rate of DR calculated by the TCM in the non-DR, mild-NPDR, moderate-NPDR, severe-NPDR and PDR groups from fundus photography was lower than that in the CNN-DR1 and CNN-DR2 groups (Table 4). CNN-DR1 and CNN-DR2 represented the average lesion area rate of DR calculated by the CNN from fundus photography and angiography, respectively. Importantly, the average lesion area rate of DR from CNN-DR2 was higher than that from CNN-DR1. For analyzing the staging of DN, the lesion area rate of DN calculated by CNN in the non-DR, mild-NPDR, moderate-NPDR, severe-NPDR and PDR groups from ECT images was higher than that of TCM (Table 5 and Fig. 4). In summary, these results indicated that our proposed methods provided enhanced accuracy in classifying DR and DN and showed more enhanced outputs compared with the traditional methods.
Table 4
The lesion area rate of DR on Fundus photography(DR1) and angiography(DR2) computed by the Traditional Calculation Method(TCM) and Convolutional Neural Network.
Group | Non-DR | Mild-NPDR | Moderate-NPDR | Severe-NPDR | PDR |
TCM(%) | 1.75 ± 0.36 | 13.98 ± 1.51 | 33.14 ± 4.81 | 45.98 ± 3.78 | 74.86 ± 2.98 |
CNN-DR1(%) | 3.94 ± 0.58 | 24.41 ± 3.91 | 45.41 ± 1.99 | 68.42 ± 4.51 | 84.89 ± 2.79 |
CNN-DR2(%) | 3.31 ± 0.77 | 33.42 ± 2.83 | 61.61 ± 2.59 | 75.24 ± 2.98 | 94.62 ± 1.52 |
P values | 0.453 | 0.047 | 0.025 | 0.012 | 0.031 |
Table 5
The lesion area rate of DN on ECT images computed by the Traditional Calculation Method(TCM) and Convolutional Neural Network.
Group | Non-DR | Mild-NPDR | Mod-NPDR | S-NPDR | PDR |
TCM(%) | 2.45 ± 0.57 | 15.36 ± 1.76 | 28.45 ± 2.81 | 39.01 ± 2.29 | 67.29 ± 1.89 |
CNN-DN(%) | 4.21 ± 0.28 | 26.81 ± 1.88 | 41.29 ± 1.74 | 62.37 ± 2.48 | 85.23 ± 1.93 |
P values | 0.281 | 0.036 | 0.001 | 0.007 | 0.014 |
3.2 Analyzing the medical history and laboratory data of patients in different DR stages
In this part, we found that with the extension of T2DM duration, the degree of DR gradually worsened, and a history of smoking was an important factor in the progression of DR through analysis of medical history data. Moreover, we discovered that the average SBP, HbA1c, TC, TG and LDL-C levels increased gradually in the mild-NPDR, moderate-NPDR, severe-NPDR and PDR groups compared with the non-DR group, and these values reached the highest value in the PDR group(Table 6). Interestingly, the change in HDL-C was opposite to the above trend; that is, the average amount of HDL-C decreased in the mild-NPDR, moderate-NPDR, severe-NPDR and PDR groups compared with the non-DR group, and these data reached the lowest value in the PDR group. There was no significant difference in age, sex, hypertension, alcohol consumption, DBP or BMI among the five groups (P > 0.05).
Table 6
Comparison of baseline characteristics in different DR stages.
Variable | Non-DR (n = 120) | Mild-NPDR (n = 120) | Moderate-NPDR (n = 120) | Severe-PDR (n = 120) | PDR (n = 120) | p value* |
Age (year) | 62.89 ± 10.29 | 62.73 ± 12.08 | 61.47 ± 11.39 | 62.14 ± 10.97 | 63.02 ± 11.28 | 0.423 |
Male gender (%) | 52.91 | 48.32 | 54.72 | 44.72 | 46.38 | 0.141 |
Duration ofT2D (years) | 4.53 ± 2.38 | 7.61 ± 6.46 | 9.03 ± 7.06 | 11.68 ± 6.94 | 12.68 ± 5.87 | 0.027 |
Hypertension(%) | 34.92 | 47.85 | 52.78 | 54.38 | 51.94 | 0.291 |
Alcohol consumption(%) | 24.59 | 30.23 | 28.76 | 14.97 | 13.08 | 0.372 |
Smoker(%) | 24.57 | 32.57 | 44.37 | 49.28 | 54.83 | 0.029 |
SBP (mmHg) | 117.23 ± 10.23 | 132.38 ± 14.25 | 142.32 ± 15.28 | 147.91 ± 13.29 | 152.38 ± 14.29 | 0.007 |
DBP (mmHg) | 68.92 ± 7.92 | 78.29 ± 11.39 | 81.32 ± 11.42 | 78.29 ± 11.38 | 83.12 ± 10.89 | 0.139 |
BMI (kg/m 2 ) | 24.28(23.89, 26.82) | 25.32(23.83, 27.89) | 25.81(22.48,27.91) | 26.35(23.82,28.31) | 25.81(22.42,27.79) | 0.271 |
HbA1c (%) | 6.89 ± 0.92 | 7.42 ± 1.28 | 7.92 ± 1.42 | 8.41 ± 1.28 | 8.92 ± 1.01 | 0.004 |
TC(mmol/L) | 5.68 ± 0.98 | 6.02 ± 1.15 | 6.28 ± 1.02 | 6.58 ± 0.92 | 6.97 ± 1.02 | 0.037 |
TG (mmol/L) | 1.82 ± 0.59 | 1.98 ± 0.92 | 2.31 ± 0.89 | 2.78 ± 1.38 | 3.12 ± 1.25 | 0.001 |
HDL-C (mmol/L) | 1.34(0.93,1.78) | 1.27(0.89,1.57) | 1.14(0.92,1.38) | 1.02(0.91,1.29) | 0.92(0.79,1.19) | 0.013 |
LDL-C (mmol/L) | 3.87 ± 0.82 | 4.12 ± 0.79 | 4.32 ± 1.12 | 4.56 ± 1.08 | 4.89 ± 1.12 | 0.021 |
3.3 Analyzing the renal function index of patients in different DR stages
To detect the association of DR and DN, we investigated the change trend of Scr, BUN, UAlb, ACR, and GFR in different stages of DR. Surprisingly, we discovered that the average levels of Scr, BUN, UAlb and ACR increased gradually in the Mild-NPDR, Moderate-NPDR, Severe-NPDR and PDR groups compared with the Non-DR group, and these data reached the highest value in the PDR group. After further calculations of GFR based on relevant indicators, we found that the average GFR decreased in the mild-NPDR, moderate-NPDR, severe-NPDR and PDR groups compared with the non-DR group, and these data reached the lowest value in the PDR group (Table 7). Then, logistic regression analysis was performed to evaluate factors associated with DR (Table 8). After adjusting for age, gender, duration of T2DM, history of Smoking, SBP ≥ 130 mmHg, HbA1c, TC, TG, HDL-C, LDL-C, Scr, BUN, UAlb, ACR and GFR, DR was significantly associated with duration of T2DM (OR = 1.52, 95%CI 1.21–1.78; p = 0.002), Smoking(OR = 1.89, 95%CI 1.67–2.27; p = 0.002), HbA1c (OR = 2.25, 95%CI 1.49–3.71;p = 0.003), TC(OR = 1.79, 95%CI 0.94–2.61; p = 0.004), TC(OR = 1.79, 95%CI 0.94–2.61; p = 0.004), TG(OR = 1.52, 95%CI 1.21–1.78; p = 0.001), HDL-C (OR = 1.59, 95%CI 1.25–2.04; p = 0.003), LDL-C(OR = 1.42, 95%CI 1.27–1.68; p = 0.042), Scr(OR = 1.47, 95%CI 0.94–1.67; p = 0.0039), BUN(OR = 1.54, 95% CI 1.23–1.74; p = 0.002), UAlb(OR = 1.79, 95%CI 1.46–2.27; p = 0.041), ACR(OR = 2.04, 95%CI 1.89–2.56; p = 0.007), and GFR(OR = 2.47, 95% CI 1.92–3.18; p = 0.037). The results showed that duration of T2D, smoking, HbA1c, TC, TG, HDL-c, LDL-c, UAlb, Scr, BUN, UAlb, ACR, GFR, ACR, and GFR were independent risk factors for DR, with a statistically significant difference (P < 0.05). Furthermore, we analyzed the abnormal rate of DN in different degrees of DR to clarify the correlation between DR and DN. We discovered that the overall incidence rate of DN was 51%, and the incidence of DN in the non-DR, mild-NPDR, moderate-NPDR, severe-NPDR and PDR groups was 4.17%, 28.33%, 55%, 75.83% and 91.67%, respectively (Table 9). The results suggested that the incidence rate of DN gradually increased with the aggravation of DR, and the difference was statistically significant (p < 0.05).
Table 7
The data statistics and analysis of Scr、BUN、UAlb、ACR、GFR among five groups
Variable | Non-DR (n = 120) | Mild-NPDR (n = 120) | Moderate-NPDR (n = 120) | Severe-PDR (n = 120) | PDR (n = 120) | p value* |
Scr (umol/L) | 40.82 ± 13.28 | 65.29 ± 17.85 | 89.28 ± 16.92 | 110.39 ± 16.29 | 130.24 ± 18.23 | 0.005 |
BUN(mmol/L) | 3.28 ± 1.28 | 4.83 ± 1.82 | 6.53 ± 1.59 | 7.02 ± 1.12 | 7.47 ± 1.48 | 0.037 |
UAlb (mg/24h) | 134.92±15.29 | 145.37 ± 16.92 | 153.49 ± 17.91 | 157.82 ± 15.42 | 165.02 ± 14.92 | 0.003 |
ACR (g/Cr) | 19.32 ± 7.39 | 35.82 ± 15.81 | 191.82 ± 19.21 | 443.38 ± 14.92 | 657.19 ± 15.99 | 0.001 |
GFR (ml/min) | 120.32 ± 12.38 | 75.38 ± 10.94 | 52.39 ± 11.35 | 35.62 ± 8.97 | 25.42 ± 7.85 | 0.042 |
Table 8
Logistic regression analysis between patients with and without DR for variables associated with DR.
Variable | OR(95%CI) | P value |
Gender (male/female) | 1.25(0.87,1.54) | 0.489 |
Age (years) | 0.81(0.67,1.09) | 0.178 |
Duration of T2D (years) | 1.52(1.21,1.78) | 0.002 |
Smoking | 1.89(1.67,1.2.27) | 0.007 |
Alcohol Consumption | 0.99(0.90,1.17) | 0.291 |
SBP ≥ 130 mmHg | 1.37(1.09,1.62) | 0.384 |
HbA1c (%) | 2.25(1.49,3.71) | 0.003 |
TC (mmol/L) | 1.79(0.94,2.61) | 0.004 |
TG (mmol/L) | 1.52(1.21,1.78) | 0.001 |
HDL-C (mmol/L) | 1.59(1.25,2.04) | 0.003 |
LDL-C (mmol/L) | 1.42(1.27,1.68) | 0.042 |
Scr | 1.47(0.94,1.67) | 0.039 |
BUN | 1.54(1.23,1.74) | 0.002 |
UAlb | 1.79(1.46,2.27) | 0.041 |
ACR | 2.04(1.89,2.56) | 0.007 |
GFR | 2.47(1.92,3.18) | 0.037 |
Table 9
Analyzing the abnormal rate of DN in different degrees of DR.
Group | DN I | DN II | DN III | DN IV | DN V | Abnormal DN rate |
Non-DR | 3 | 2 | 0 | 0 | 0 | 4.17% |
Mild-NPDR | 23 | 6 | 5 | 0 | 0 | 28.33% |
Moderate-NPDR | 37 | 13 | 10 | 6 | 0 | 55% |
Severe-PDR | 43 | 16 | 15 | 11 | 6 | 75.83% |
PDR | 54 | 18 | 17 | 12 | 9 | 91.67% |
Total | 160 | 55 | 47 | 29 | 15 | 51% |
3.4 Analyzing the renal function index of patients in different DR stages by ECT imaging technology
As shown in Table 10, the blood perfusion volumes of the non-DR, mild-NPDR, moderate-NPDR, severe-NPDR and PDR groups were 87.02 ± 3.81%, 81.03 ± 4.92%, 67.83 ± 2.58%, 55.47 ± 4.29% and 38.92 ± 4.97%, respectively, while the drug uptake rates in these groups were 78.91 ± 3.21%, 74.29 ± 2.83%, 65.78 ± 2.91%, 54.12 ± 2.74% and 34.29 ± 3.21%, respectively, through the analysis of dynamic renal ECT imaging. These results indicated that with the aggravation of DN, the perfusion of renal blood flow and the renal drug uptake rate decreased. Further analysis of GFR combined with relevant data showed that the GFR in the non-DR, mild-NPDR, moderate-NPDR, severe-NPDR and PDR groups were 90.39 ± 3.28%, 85.34 ± 4.02%, 65.33 ± 3.21%, 54.02 ± 2.61% and 38.92 ± 4.97%, respectively. It was suggested that with the aggravation of DR, the GFR decreased. In summary, the above results demonstrated that the degree of DN worsened with the aggravation of DR.
Table 10
Analyzing the correlative parameters of ECT image datum in different degrees of DR.
Variable | Non-DR (n = 120) | Mild-NPDR (n = 120) | Moderate-NPDR (n = 120) | Severe-PDR (n = 120) | PDR (n = 120) | p value* |
Kidney Area(cm2) | 19.21 ± 1.82 | 23.23 ± 2.52 | 35.34± 2.72 | 48.12± 3.32 | 61.42 ± 5.83 | 0.002 |
Kidney depth(cm) | 2.23 ± 0.78 | 5.74± 1.32 | 14.45 ± 2.38 | 20.61 ± 2.47 | 27.82 ± 2.25 | 0.047 |
Perfusion% | 87.02 ± 3.81 | 81.03 ± 4.92 | 67.83 ± 2.58 | 55.47 ± 4.29 | 38.92 ± 4.97 | 0.021 |
Uptake%(Int) | 78.91 ± 3.21 | 74.29 ± 2.83 | 65.78 ± 2.91 | 54.12 ± 2.74 | 34.29 ± 3.21 | 0.003 |
GFR | 90.39 ± 3.28 | 85.34± 4.02 | 65.33 ± 3.21 | 54.02 ± 2.61 | 43.41 ± 3.27 | 0.002 |
Time to peak | 21.81 ± 2.93 | 22.52 ± 1.72 | 23.57 ± 2.87 | 22.73 ± 1.57 | 25.28 ± 2.73 | 0.281 |