Arterial spin labeling in neonatal magnetic resonance imaging - first experience and new observations

Arterial spin labeling (ASL) is a noninvasive non-contrast technique of perfusion imaging that uses endogenous water from the blood as the perfusion tracer, with very scant data on its use in neonates. The authors present the added value of ASL in the examined babies in their own material and discuss it in the light of the existing literature.

During the first 10 months after the purchase of a new magnetic resonance imaging (MRI) scanner, 123 neonates were examined using it in an MR-compatible incubator, 117 of them had brain MRI, and in 104 ASL was incorporated in the routine protocol, which resulted in prolongation of the study time by approximately 4 minutes. 3D ASL sequence uses Pulsed Continuous Arterial Spin Labeling (PCASL; aka pseudo continuous) technique.

The quality of the cerebral blood flow (CBF) maps was good in all cases but 2 because all the babies were sedated. Apart from the knowledge about normal perfusion patterns in the preterm and term neonatal brains, the use of ASL sequence provided important additional information in 11 cases (10.8%): increased CBF correlating with electroencephalographic seizure localization in otherwise normal MRI (n = 1), increased CBF in the cortex without clinical information about seizures and with posthaemorrhagic changes (n = 1), increased CBF in the brain stem and decreased in the upper parts of the brain (n = 2), probably reflecting the homeostatic mechanism which allows preferential perfusion of the vital structures of the brain stem, hypoperfusion (n = 1) or hypoperfusion with peripheral hyperperfusion (n = 1) in the area of stroke, hypoperfusion of the posterior areas of the brain in the presence of subarachnoid or epidural haemorrhage (n = 3), significantly increased CBF in the presumed nidus of arteriovenous malformation causing haemorrhage (n = 1), and lack of perfusion in the supratentorial compartment in a case of suspected brain death (n = 1).

Our short experience but relatively large volume of material encourages the use of ASL in routine neonatal MRI as a useful and non-time-consuming tool providing additional important clinical information in a significant percentage of cases.