Kim Annink

236 Chapter 11 ABSTRACT Background: Cerebral MRI in infants is usually performed with a field strength up to 3.0 Tesla (T). In adults, a growing number of studies have shown added diagnostic value of 7.0T MRI. 7.0T MRI might also be of additional value in infants with e.g. unexplained seizures. The aim of this study was to investigate the feasibility of 7.0T MRI in infants. We provide information about the safety preparations and show the first MR images of infants at 7.0T. Methods: Specific Absorption Rate (SAR) levels during 7.0T were simulated in Sim4life using an infant and adult model. A newly developed acoustic hood was used to guarantee hearing protection. Acoustic noise damping of this hood was measured and compared to the 3.0T Nordell hood and no hood. In the prospective pilot study, clinically stable infants, between term (equivalent) age and the (corrected) age of three months, underwent a 7.0T MRI immediately after their standard 3.0T MRI. 7.0T scan protocols were developed and optimized whilst scanning this cohort. Results: Global and peak SAR levels in the infant model in centered position and 50mm feet direction did not exceed the levels in the adult model. Hearing protection was guaranteed with the new hood. Twelve infants were scanned. No MRI-related adverse events occurred. It was feasible to obtain good quality imaging at 7.0T for MRA, MRV, SWI, single-shot T2-weighted imaging and MRS. T1-weighted imaging was of less quality at 7.0T. Conclusion: 7.0T MRI is feasible in infants and good quality scans could be obtained.