MAGNETIC-RESONANCE SPECTROSCOPY AND NEAR-INFRARED SPECTROSCOPY IN THEASSESSMENT OF THE ASPHYXIATED TERM INFANT

Magnetic resonance spectroscopy (MRS) and near-infrared spectroscopy ( NIRS) are capable of providing detailed information on cerebral oxidat ive metabolism in infants who have been resuscitated following an acut e asphyxial episode. In severely affected infants studied by phosphoru s and proton MRS, a consistent observation has been the development of deranged cerebral energy metabolism 12-48 hours after resuscitation, despite the maintenance of cardiovascular and respiratory homeostasis. Follow-up studies have indicated that the development of delayed ener gy failure is closely associated with the development of microcephaly and an adverse neurodevelopmental outcome. This pathophysiologic seque nce has been modelled in newborn animals, allowing the mechanisms of d elayed energy failure to be elucidated and cerebroprotective treatment s to be tested. New developments in MRS and magnetic resonance imaging will enable quantitative and highly localised information on cerebral metabolism to be obtained in asphyxiated infants, increasing the accu racy of early clinical assessment. Significant cerebral vasodilatation and vasoparalysis of the cerebral circulation have been observed by N IRS in asphyxiated infants following resuscitation, but the prognostic value of this observation remains uncertain. Technical advances. in N IRS are likely to improve the reproducibility and accuracy of the tech nique, allowing the assessment of regional cerebral haemodynamics and metabolism at the bedside. (C) 1997 Wiley-Liss, Inc.