LIMITATIONS FOR 3-DIMENSIONAL ULTRASOUND IMAGING THROUGH A BORE-HOLE TREPANATION

The intraoperative shift of neuroanatomical landmarks that serve as re ference points is an unsolved problem in current neuronavigation, Moni toring the position of these landmarks requires repeated intraoperativ e imaging. We analyzed the effectiveness of a 3-D ultrasound system fo r imaging through a bore-hole trepanation, A tissue-mimicking ultrasou nd phantom and plastic pads with bore-holes were utilized for in vitro tests of the system. Reducing the diameter of the simulated bore-hole decreased the image quality and reduced the field of view. The multip le plane mode of the 3-D ultrasound system allows reconstruction of im ages in arbitrary imaging planes on the basis of intraoperatively acqu ired 3-D datasets, Selecting planes that are coplanar with preoperativ e MRI scans, we were able to identify neuroanatomical landmarks in the reconstructed ultrasound images. Repeated 3-D ultrasound during a pro cedure might, therefore, allow recognition of a shift of these landmar ks. (C) 1998 World Federation for Ultrasound in Medicine & Biology.