TABLE 2.

Subject characteristics for morphologic analysis.

	Extremely preterm infants (n = 13)	Very preterm infants (n = 21)	p-value
Age at birth (days)*	184 ± 7	212 ± 8.2	< 0.0001
Sex
Boy	8 (61.5%)	10 (47.6%)	0.501
Girl	5 (38.5%)	11 (52.4%)
MRI characteristics
Age at MRI (days)*	270 ± 15.1	263 ± 10.7	0.087
MRI scanner
– Scanner 1	10 (76.9%)	11 (52.4%)	0.15
– Scanner 2	3 (23.1%)	10 (47.6%)
Morphological sequences:
– MPRAGE 1	12 (92.3%)	17 (81%)	0.34
– MPRAGE 2	1 (7.7%)	4 (19%)
Etiology of prematurity
Spontaneous preterm labor	1 (7.7%)	1 (4.8%)	0.73
High blood pressure	1 (7.7%)	11 (52.4%)	0.01
Chorioamnionitis	5 (38.5%)	1 (4.5%)	0.02
Suspicion of infection	11 (84.6%)	10 (47.6%)	0.06
Premature rupture of membranes	6 (46.2%)	4 (19%)	0.14
Metrorrhagia during the second or third trimester of pregnancy	3 (23.1%)	4 (19%)	0.78
Perinatal
Antenatal steroids	12 (97.3%)	21 (100%)	0.38
In-utero growth restriction	1 (7.7%)	3 (14.3%)	0.55
Cesarean delivery	8 (61.5%)	12 (57.1%)	0.80
Birth weight (g)	921 ± 169	1,360 ± 308	0.001
Postnatal steroids	6 (46.2%)	0 (0%)	< 0.0001
Complications
MRI abnormalities	3 (27.3%)	7 (33.3%)	0.52
– Hemorrhage	1 (7.8%)	1 (4.8%)	0.73
– WM lesions	1 (7.8%)	5 (23.8%)	0.21
Clinical abnormalities	13 (100%)	13 (61.9%)	0.002
– Bronchopulmonary dysplasia	11 (84.6%)	7 (33.3%)	0.003
– Patent ductus arteriosus	13 (100%)	8 (38.1%)	< 0.0001
– Infection	12 (92.3%)	9 (42.9%)	0.008
– Necrotizing enterocolitis	2 (15.4%)	1 (4.8%)	0.3

Data are expressed in mean ± sd numbers (percentage). The significant p-values are in bold characters. *Age at birth and age at MRI are reported in days of gestation, i.e., from onset of last menstrual period.