Magnetic resonance imaging of neonatal encephalopathy at 4.7 tesla: initial experiences.
OBJECTIVE
The goals were to develop safe 4.7-T MRI examination protocols for newborn infants and to explore the advantages of this field strength in neonatal encephalopathy.


METHODS
Nine ventilated newborn infants with moderate or severe encephalopathy were studied at 4.7 T, with ethical approval and informed parental consent. The custom-made, 4.7-T-compatible, neonatal patient management system included acoustic noise protection and physiologic monitoring. An adult head coil was used. Acquisition parameters for T2-weighted fast spin echo MRI and a variety of T1-weighted methods were adapted for MRI of neonatal brain at 4.7 T. The pulse sequences used had a radiofrequency specific absorption rate of <2 W/kg.


RESULTS
Physiologic measures were normal throughout each scan. T2-weighted fast spin echo imaging provided better anatomic resolution and gray/white matter contrast than typically obtained at 1.5 T; T1-weighted images were less impressive.


CONCLUSIONS
With appropriate safety precautions, MRI of newborn infants undergoing intensive care is as feasible at 4.7 T as it is at 1.5 T; our initial studies produced T2-weighted fast spin echo images with more detail than commonly obtained at 1.5 T. Although T1-weighted images were not adequately informative, additional pulse sequence optimization may be advantageous. A smaller neonatal head coil should also permit greater flexibility in acquisition parameters and even more anatomic resolution and tissue contrast. In neonatal encephalopathy, interpretation of the T2-weighted pathologic detail in combination with comprehensive neurodevelopmental follow-up should improve prognostic accuracy and enable more patient-specific therapeutic interventions. In addition, more precise relationships between structural changes and functional impairment may be defined.
De Vita
Enrico
E
Department of Medical Physics and Bio-Engineering, Elizabeth Garrett Anderson Hospital, University College London Hospitals National Health Service Foundation Trust, London, United Kingdom.
Bainbridge
Alan
A
Cheong
Jeanie L Y
JL
Hagmann
Cornelia
C
Lombard
Rosarie
R
Chong
Wui K
WK
Wyatt
John S
JS
Cady
Ernest B
EB
Ordidge
Roger J
RJ
Robertson
Nicola J
NJ
D001927:Brain Diseases / Q000175:diagnosis*; D006801:Humans; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012720:Severity of Illness Index