Stitching 3D ultrasound head images of neonates to monitor changes in ventricular volume

Ultrasound (US) images are taken in 3-dimensional (3D) space to monitor the changes in the ventricular volume of neonates. Due to the small field of view of US imaging, the head image is taken as two parts. To properly monitor and analyze the images, the two parts need to be stitched together in 3D space. In this paper, we propose a technique based on rigid registration for this purpose. User provided corresponding landmarks of the two images are used for coarse alignment. Then mutual information based rigid transformation is performed for fine alignment of moving image on to the fixed image. Finally, the fixed and moving images are stitched together to produce the final output. Furthermore, we have analyzed the optimal parameter settings for the registration procedure to minimize the registration error. We achieved a mean registration accuracy of 2.71mm for four data sets of neonatal 3D US head images using the proposed method.