Cerebral perfusion in infants and neonates: preliminary results obtained using dynamic susceptibility contrast enhanced magnetic resonance imaging

Abstract

Background: Previous studies have used the dynamic susceptibility contrast enhanced (DSCE) magnetic resonance (MR) imaging technique to measure cerebral perfusion in adults.

Objective: To assess the feasibility of the technique in a heterogeneous cohort of sick human infants and identify cerebral perfusion abnormalities.

Methods: Perfusion measurements were made by characterising the changing concentration of an injected bolus of contrast agent using a series of MR images acquired during the first pass of the contrast bolus. Qualitative values of relative cerebral blood flow (rCBF) were then calculated from these data on a pixel by pixel basis to generate parametric maps of perfusion.

Results: Images of perfusion were successfully calculated from 12 out of 27 neonates and infants, all with established cerebral pathology. Normal vascular anatomical structures such as the circle of Willis were identified within all calculated images. Values of rCBF were generally larger in grey matter than in white matter. In several patients, perfusion abnormalities resulted in structural abnormalities which were detected in conventional MR imaging at follow up. The acquisition of perfusion data was most difficult when the least mature brains were examined because of motion artefacts and a smaller head size with a lower level of rCBF than adults.

Conclusions: This preliminary study shows that: (a) maps of rCBF can be acquired from neonates and infants; (b) characterisation of the bolus passage becomes progressively easier as the brain matures; (c) early abnormalities in cerebral perfusion may have negative prognostic implications; (d) the main difficulty when using the DSCE technique to study neonates relates to image artefacts resulting from bulk head motion.

Figure 1

Magnetic resonance (MR) structural-functional comparison. Conventional T2 weighted images (A and C) versus MR perfusion images (B and D); axial sections obtained at two levels of the brain. Functional data are displayed using a non-linear colour scale. CW, Circle of Willis; SS, sagittal sinus; L, left. See text for further details.

Figure 2

Magnetic resonance (MR) structural-functional comparison in hypoxic ischaemic encephalopathy. Conventional T2 weighted images (A and C) versus MR perfusion images (B and D); axial sections obtained at two levels of the brain. Colour conventions as in fig 1. Arrows indicate regions of hypoperfusion in the occipital cortex at the age of 13 days (B) corresponding to cystic lesions in the conventional MR at the age of 10 weeks (C). A–C were acquired from a patient with hypoxic ischaemic encephalopathy, whereas D was obtained from a different patient with convulsions. See text for further details.