Noninvasive MRI Measures of Microstructural and Cerebrovascular Changes During Normal Swine Brain Development

• Published in: Pediatric research Vol. 69; no. 7; pp. 418 - 424
• Main Authors: Winter, Jeff D, Dorner, Stephanie, Lukovic, Jelena, Fisher, Joseph A, St. Lawrence, Keith S, Kassner, Andrea
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group US 01-05-2011
• Subjects: 631/136; 631/1647/767/1424; 692/700/1421/65; Age Factors; Aging; Animals; Body Weight; Brain - blood supply; Brain - growth & development; Carbon Dioxide - blood; Cerebrovascular Circulation; Diffusion Magnetic Resonance Imaging; Exhalation; Image Interpretation, Computer-Assisted; Imaging, Three-Dimensional; Linear Models; Magnetic Resonance Imaging; Medicine; Medicine & Public Health; Models, Animal; Oxygen - blood; Partial Pressure; Pediatric Surgery; Pediatrics; Regional Blood Flow; Swine; translational-investigation
• ISSN: 0031-3998; 1530-0447
• DOI: 10.1203/PDR.0b013e3182110f7e

The swine brain is emerging as a potentially valuable translational animal model of neurodevelopment and offers the ability to assess the impact of experimentally induced neurological disorders. The goal for this study was to characterize swine brain development using noninvasive MRI measures of microstructural and cerebrovascular changes. Thirteen pigs at various postnatal ages (2.3–43.5 kg) were imaged on a 1.5-Tesla MRI system. Microstructural changes were assessed using diffusion tensor imaging measures of mean diffusivity and fractional anisotropy. Cerebrovascular changes were assessed using arterial spin labeling measures of baseline cerebral blood flow (CBF) and the cerebrovascular reactivity (CVR) of the blood-oxygen level dependent (BOLD) MRI signal to CO
2
. We found a positive logarithmic relationship for regional tissue volumes and fractional anisotropy with body weight, which is similar to the pattern reported in the developing human brain. Unlike in the maturing human brain, no consistent changes in mean diffusivity or baseline CBF with development were observed. Changes in BOLD CVR exhibited a positive logarithmic relationship with body weight, which may impact the interpretation of functional MRI results at different stages of development. This animal model can be validated by applying the same noninvasive measures in humans.