Background
Methods
Study population
MRI imaging
Diffusion processing
Network analysis
Network metrics | Definitions | Descriptions |
---|---|---|
Measures of segregation | ||
Clustering coefficient (Cp) | \( {L}_p=\frac{1}{N\left(N-1\right)}\sum \limits_{i\in G}\sum \limits_{j\in G,j\ne i}{L}_{ij} \) | Lij is the shortest path length between nodes i and j, N is the set of all nodes in the network G. |
Local efficiency (Eloc) | \( {E}_{local}=\frac{1}{N}\sum \limits_{i\in G}{E}_{local,i} \) | Elocal, i is the local efficiency of node i. |
Measures of integration | ||
Characteristic path length (Lp) | \( {C}_p=\frac{1}{N}\sum \limits_{i\in G}\frac{2\ast {E}_i}{k_i\left({k}_i-1\right)} \) | ki is the degree of node i, Ei is the number of edges that consists of the neighbors of node i. |
Global efficiency (Eglob) | \( {E}_{glob}=\frac{1}{N\left(N-1\right)}\sum \limits_{i\in G}\sum \limits_{j\in G,j\ne i}\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{${L}_{ij}$}\right. \) | It is inversely related to Lp. |
Other concepts | ||
Small-worldness (σ) | \( \upsigma =\frac{L_p/{L}_{ran}}{C_p/{C}_{ran}} \) | σ measures small-worldness. Cran and Lran were averaged from 100 matched random networks. |
Statistical analyses
Results
Variables | Preterm with GMH (n = 13) | Preterm without GMH (n = 42) | Term group (n = 24) | P value preterm without GMH vs. term | P value (with vs. without GMH) |
---|---|---|---|---|---|
GA, wk | 27.4 ± 3.1 | 30.1 ± 3.8 | 38.1 ± 1.0 | < 0.001 | 0.002 |
BW, g | 909.2 ± 373.1 | 1373.5 ± 471.6 | 3142.9 ± 306.9 | < 0.001 | 0.002 |
HC, cm | 25.1 ± 3.5 | 27.4 ± 3.1 | 34.0 ± 1.1 | < 0.001 | 0.004 |
Cesarean section | 8 (66.7) | 36 (85.7) | 10 (41.7) | 0.011 | 0.203 |
Male sex | 7 (53.8) | 19 (45.2) | 18 (75.1) | 0.028 | 0.068 |
HC MRI, cm | 33.1 ± 1.2 | 33.9 ± 1.5 | 34.7 ± 2.3 | 0.079 | 0.068 |
Age at MRI scan, wk | 37.2 ± 1.4 | 37.8 ± 1.7 | 39.8 ± 0.9 | < 0.001 | 0.116 |
Culture-proven sepsis | 3 (23.1) | 6 (14.3) | – | – | 0.428 |
NEC (requiring surgery) | 1 (7.1) | 1 (2.2) | – | – | 0.925 |
TPN days | 44.42 ± 28.16 | 30.61 ± 29.6 | 0.156 | ||
BPD | 10 (76.9) | 21 (50.0) | – | – | 0.116 |
Variable | Extremely preterm < 28 wks (n = 21) | Very preterm 28 to 32 wks (n = 18) | Moderate to late preterm 33 to 36 wks (n = 16) | P value among groups | Adjusted Pa among groups |
---|---|---|---|---|---|
Bi Clustering coef. | 0.573 ± 0.024 | 0.556 ± 0.032 | 0.564 ± 0.024 | 0.201 | 0.471 |
Bi Local eff. | 0.770 ± 0.021 | 0.759 ± 0.027 | 0.761 ± 0.021 | 0.305 | 0.701 |
Bi cPL | 1.910 ± 0.090 | 1.882 ± 0.091 | 1.897 ± 0.046 | 0.583 | 0.684 |
Bi Global eff. | 0.599 ± 0.023 | 0.606 ± 0.025 | 0.601 ± 0.012 | 0.573 | 0.501 |
Bi Small-worldness | 1.543 ± 0.147 | 1.486 ± 0.177 | 1.462 ± 0.095 | 0.221 | 0.882 |
wFA Clustering coef. | 0.091 ± 0.009 | 0.089 ± 0.013 | 0.088 ± 0.006 | 0.629 | 0.471 |
wFA Local eff. | 0.145 ± 0.012 | 0.144 ± 0.020 | 0.140 ± 0.009 | 0.524 | 0.701 |
wFA cPL | 0.283 ± 0.020 | 0.277 ± 0.034 | 0.275 ± 0.018 | 0.654 | 0.684 |
wFA Global eff. | 4.085 ± 0.310 | 4.176 ± 0.454 | 4.226 ± 0.237 | 0.454 | 0.501 |
wFA small-worldness | 1.464 ± 0.168 | 1.396 ± 0.187 | 1.361 ± 0.090 | 0.128 | 0.921 |
Variable | Preterm with GMH (n = 13) | Preterm without GMH (n = 42) | Full-term (n = 24) | Adjusted Pa (preterm without GMH vs. term) | Adjusted P a (with vs. without GMH) |
---|---|---|---|---|---|
Bi Clustering coef. | 0.572 ± 0.023 | 0.562 ± 0.028 | 0.557 ± 0.037 | 0.921 | 0.375 |
Bi Local eff. | 0.769 ± 0.021 | 0.762 ± 0.024 | 0.755 ± 0.028 | 0.630 | 0.486 |
Bi cPL | 1.910 ± 0.101 | 1.893 ± 0.708 | 1.870 ± 0.064 | 0.414 | 0.507 |
Bi Global eff. | 0.599 ± 0.026 | 0.603 ± 0.019 | 0.609 ± 0.018 | 0.423 | 0.474 |
Bi Small-worldness | 1.531 ± 0.166 | 1.488 ± 0.139 | 1.456 ± 0.104 | 0.718 | 0.748 |
wFA Clustering coef. | 0.093 ± 0.015 | 0.088 ± 0.007 | 0.094 ± 0.007 | 0.375 | 0.027 |
wFA Local eff. | 0.151 ± 0.022 | 0.141 ± 0.010 | 0.152 ± 0.014 | 0.486 | 0.025 |
wFA cPL | 0.291 ± 0.035 | 0.275 ± 0.019 | 0.296 ± 0.038 | 0.507 | 0.020 |
wFA Global eff. | 3.998 ± 0.473 | 4.212 ± 0.281 | 3.926 ± 0.420 | 0.474 | 0.048 |
wFA small-worldness | 1.464 ± 0.179 | 1.391 ± 0.148 | 1.353 ± 0.099 | 0.748 | 0.479 |