<title>Viewing 3D MRI data in perspective</title>

Abstract

In medical imaging applications, 3D morphological data set is often presented in 2D format without considering visual perspective. Without perspective, the resulting image can be counterintuitive to natural human visual perception, specially in a setting of MR guided neurosurgical procedure where depth perception is crucial. To address this problem we have developed a new projection scheme that incorporates linear perspective transformation in various image reconstructions, including MR angiographical projection. In the scheme, an imaginary picture plane (PP) can be placed within or immediately in front of a 3D object, and the stand point (SP) of an observer is fixed at a normal viewing distance os 25 cm in front of the picture plane. A clinical 3D angiography data set (TR/TF/Flipequals30/5.4/15) was obtained from a patient head on a 1.5T MR scanner in 4 min 10 sec (87.5% rectangular, 52% scan). The length, width and height of the image volume were 200mm, 200mm and 72.4mm respectively, corresponding to an effective matrix size of 236x512x44 in transverse orientation (512x512x88 after interpolation). Maximum intensity project (MaxIP) algorithm was used along the viewing trace of perspective projection than rather the parallel projection. Consecutive 36 views were obtained at a 10 degree interval azimuthally. When displayed in cine-mode, the new MaxIP images appeared realistic with an improved depth perception.