The purpose of the study is to detect structural brain changes using MRI and to correlate these findings with neurodevelopmental assessments in two-year old children previously enrolled in the NIH sponsored trial of inhaled Nitric Oxide (iNO) for the prevention of Chronic Lung Disease in preterm ventilated infants. It is hypothesized that this imaging will identify children with previously undiagnosed brain abnormalities and that the presence of structural abnormalities will be associated with deficits in motor, cognitive, and neurosensory development.

Infants born prematurely are at significant risk for hemorrhagic and ischemic brain injury. Despite improved survival rates among this population in recent years, these forms of brain injury remain frequent and have considerable consequences. Periventricular leukomalacia (PVL), a disease characterized by necrosis of the cerebral white matter in a characteristic distribution, is one of the most common types of brain injury seen in premature infants. MRI technology now allows for better anatomical resolution resulting in improvements in diagnostic accuracy. The current standard practice is not to perform routine MRI examinations on premature infants, nor is it routine to perform surveillance brain imaging in children after leaving the NICU. In their 2002 Practice Parameter for neuroimaging in the neonate, the American Academy of Neurology and the Practice Committee of the Child Neurology Society acknowledge the superiority of MRI in detection of brain lesions in premature infants, but fall short of recommending routine MRI scanning on the basis of a lack of information correlating MRI findings to neurodevelopmental outcomes. We now have a unique opportunity to help provide such information.

Inclusion Criteria:

• must be participants in trial (NHLBI-UO1-HL62514-05A1 and FDA IND # 58,146 - Roberta A Ballard PI) of inhaled Nitric Oxide (iNO) for the prevention of Chronic Lung Disease in preterm ventilated infants
• gestational age between 24 months and 27 months

Exclusion Criteria:

• history of allergy to sedation agents
• medical conditions which may pose a threat to airway integrity (i.e., Pierre-Robin sequence, intercurrent respiratory illness)
• other conditions which may otherwise place subjects at increased risk for complications from sedation and MRI examination