MRI Characteristics And Risk Factors Of Encephalopthy Of Prematurity

Objective Encephalopathy of prematurity (EOP) is an important form of premature brain injury. The morbility of EOP is increasing with the rise of premature birth rate and the improvement of treatment, and it is one of the major reasons for nervous system sequela. Its diagnosis is highly dependent on the magnetic resonance imaging (MRI). Its risk factors are still unclear. The aim of this study was to explore the MRI manifestation and risk factors of EOP, so as to find an access to the early prevention, early diagnosis, effective treatment and prognosis.Methods This study collected MRI and clinical data of premature infants who were admitted to NICU of Children’s Hospital of Fudan University during the time between January1,2009and December31,2011. The manifestation and lesions distribution in MRI were analysed. Then preterm infants (less than32weeks gestational age or birth weigh less than1500g) were divided into EOP group and normal group according to MRI characteristics. Clinical risk factors were analysed using SPSS19.0.Results956preterm infants were tested with MRI.58.05%(555/956) of which had normal MRI apperance, whereas25.57%(254/956) showed manifestations of EOP.85.37%of patients with EOP were not together with other brain injourys. The morbidity rate of infants with purulent meningitis were higher (34.29%).33.33%infants with Apgar Score<5had EOP. The morbidity rate of infants with gestational age <32weeks, birth weight<1500g, fetal distress, premature rupture of membrane, sepsis or neonatal necrotizeing enteroclitise were between20.22%and29.03%. The proportion of preterm infants with premature rupture of membrane was highest (77.05%). However, the proportion of preterm infants with birth weight<1500g, purulent meningitis or sepsis was higher (43.06%,41.67%and40.48%, respectively).73.57%(181/246) EOP were non-cystic EOP.55.80%(101/246) of non-cystic EOP had bilateral brain white matter injury. Most infants with non-cystic EOP had multi-position lesions.26.42%(65/246) were cystic EOP.4infants of cystic EOP had multi-cystic lesions.29.23%(19/65) of cystic EOP had bilateral cystic lesions.64.06%(41/64) infants of cystic EOP only had one cystic lesion. Periventricular and cerebral lobe white matter were primary distributions of these lesions (99/246and115/246patients, respectively). Cystic lesions were primarily distributed in periventricular whiter matter (46/65), however, more non-cystic EOP were found non-cystic lesions in cerebral lobe whiter matter (96/181) than periventricular whiter matter (57/181). Both cystic and non-cystic EOP, which were found lesions in periventricular white matter, were significantly located beside body of lateral ventricle (cystic EOP37/42patients; non-cystic EOP43/57patients). More cystic lesions were distributed in frontal lobe (10/19) than other brain lobes, while moer non-cystic EOP were found lesions in frontal lobe (52/96) and parietal lobe (39/96).10(4.07%) preterm infants with EOP have clinical manifestation of nervous system.47.69%(31/65) of preterm infants with cystic EOP were also examined with cranial ultrasound.22.58%(7/31) of preterm infants with cystic EOP could be detacted by ultrasound, while54.85%(17/31) patients only magnifested ventricular dilatation in the ultrasound images.40.43%(76/188) of preterm infants with non-cystic EOP were tested with cranial ultrasound too. Merely14.47%patients (11/76) were also found non-cystic lesions in these ultrasound images, However,50%of patients’ultrasound images was normal, and35.53%of patients’(27persons) ultrasound images only showed ventricular dilatation.,Data of122infants with EOP and310normal infants were collected for risk factors analysis. The results showed that1minute and5minute Apgar score, non-Shanghai census register, first one of multiplets, vaginal delivery, aids to vaginal delivery, duration of oxygen support, duration of mechanical ventilation and/or nCPAP ventilation, purulent meningitis, fungal septicemia and C-reactive protein (CRP) were risk factors for EOP. Preterm infants with fungal septicemia were most vulnerable to EOP (OR15.98;95%CI1.90～134.19), and first one of multiplets was the second risk factor of EOP (OR12.68;95%CI4.66～34.51), then the third one was aids to vaginal delivery (OR6.581;95%CI1.259-34.391).The chi-square for trend test indicated that the risk of EOP was increasing with the longer duration of oxygen support, longer duration of mechanical ventilation and/or nCPAP ventilation or CRP rising. Logistic regression analysis showed that non-Shanghai census register, first one of multiplets,5minute Apgar score<5and fungalsepticemia were independent risk factors of EOP. After Logistic regression, preterm infants with fungal septicemia were also the most vulnerable to EOP (OR6.222;95%C11.155-33.526).Conclusions This study indicated that the morbidity rate of preterm infants was25.73%. EOP is an important part of preterm white matter injury. The number of non-cystic EOP was more than cystic EOP. Lesions of brain in infants with EOP were more often distributed in periventricular and cerebral lobe white matter.Preterm infants with EOP scarely showed clinical manifestation of nervous system. The diagnostic sensitivity of cranial ultrasound for EOP was low. So EOP need MRI examination to assist early diagnosis. The morbidity rate of EOP is very high. Its risk factors were complicated.1minute and5minute Apgar score, non-Shanghai census register, first one of multiplets, vaginal delivery, aids to vaginal delivery,duration of oxygen support, duration of mechanical ventilation and/or nCPAP ventilation, purulent meningitis, fungal septicemia and C-reactive protein were risk factors of EOP. Non-Shanghai census register, first one of multiplets,5minute Apgar score <5and fungalsepticemia were independent risk factors for EOP.