Near-automatic detection of arrow-shaped markers for CT/MRI fusion

An algorithm is presented to detect arrow-shaped skin markers that have been designed for matching of CT and MR images. The markers can be located in the images with subslice accuracy, which allows accurate registration even in standard imaging protocols employing thick slices and/or large interslice gaps. In the past, extracting the marker information from the images has been a highly interactive process. The algorithm described only requires a minimal amount of user interaction.<>