Background and aims Pilot study to explore feasibility of a colour Doppler technique for monitoring cerebral perfusion at the level of microvessels.
Methods Between March 1st, 2011, and January 30th, 2013, all admitted infants born before 29 weeks of gestation were eligible for Doppler imaging. Perfusion images were acquired in a standard coronal plane. Image quality was assessed by two authors (MR, PG). The region of interest (ROI) was manually selected. A segmentation tool was developed to separate colour data from the greyscale 2D images, leading to a percentage and number of colour pixels in the image (Doppler colour index; DCI). Intra- and interobserver agreement was analysed.
Results Intra- and interobserver agreement for placement of ROIs was good (bias -0.24 resp. -0.74 percentage points). Colour Doppler was able to depict microvessels in cortex, white matter and deep grey matter. The median DCI in a region of cortex-white matter was 7.8% with a wide range (1.4%-25.6%). There was no significant difference between the left and right hemisphere (Mann-Whitney U, P-value 0.61). Clinically relevant observations were tabulated, e.g. distant effect of GMH on regional perfusion.