186 Non-Invasive Cerebral Perfusion Measurements In Term Neonates and Premature Infants Using Arterial Spin Labelling

Abstract

Background: Sick premature and term neonates have a vulnerable cerebral circulation. Studies of the cerebral circulation have been performed previously using either invasive methods, or non-invasive approaches that have not proven satisfactory. However, a non-invasive MR-method for measuring brain perfusion has recently been developed. MR Arterial spin-labelling (ASL) is an MR technique that enables accurate maps of regional cerebral perfusion to be acquired in a few minutes. The purpose of this study was to investigate the feasibility of ASL as a method for measuring cerebral perfusion in healthy premature infants at term equivalent age and in term neonates. Methods: 20 infants were enrolled. Nine infants were born prematurely (group 1), median GA= 31 w, neonatal period uneventful. 11 infants were healthy term neonates (group 2). Both groups were MR scanned at term age. The local ethics committee accepted the study and informed parental consent was obtained. For the MR examination infants were unsedated, sleeping naturally after a feed. Silicone ear cups were used for noise protection. Images were acquired on a Siemens Magnetom Trio 3T scanner using a PICORE QUIPSS II sequence. Control and tag images acquired during motion-free periods were subtracted to give perfusion-weighted ASL images. Regions of interest (ROIs) were drawn on the control images in the basal ganglia (BG), cortical grey matter (GM) and white matter (WM). Mean perfusion values were calculated for each ROI and each subject. Results: Results are shown in Table and an example in Figure. ASL was found to be a feasible method for measuring perfusion in neonates. Motion is a substantial problem that can be solved in most cases. Acquisition time is short (6 minutes). The calculated values correspond to values acquired using other methods. Perfusion is highest in BG and lowest in the WM. We found higher perfusion values in BG and GM for premature infants at term equivalent age as compared with term neonates. These differences were highly significant (p values .001). Conclusion: ASL is feasible for measuring perfusion in neonates. Values are reliable. Perfusion values in BG are much higher as compared with GM and especially WM. Values in WM are low. Values of perfusion in premature infants at term equivalent age are significantly higher than in term neonates. ASL, allowing serial perfusion measurements, offers the possibility of better understanding pathogenetical mechanisms underlying brain damage in high-risk neonates.