Graphical User Interface for Reconstruction and Visualization of High-Resolution Susceptibility-Weighted MR Data

Purpose: In recent years, BOLD-MR venography [1] (also named susceptibility-weighted imaging, SWI) has been established for the examination of tumors [2, 3] and for studying physiological processes [4]. The creation of BOLD venograms starting from k-space data requires a combination of magnitude and phase information in a rather sophisticated manner. This has not been implemented in MRI scanners yet. Therefore, a platform-independent graphical user interface (GUI) has been developed for the generation and extensive analysis of SWI data. Materials and Methods: High-resolution 3D scans of the human brain of volunteers and patients were acquired with a first-order flow compensated gradient echo sequence on a 1.5 T whole-body scanner using the headcoil (TR=67 ms, TE=40 ms, flip angle=25°, FoV=256mm (192mm (64mm, matrix=512 (192 (64). IDL (RSI, Boulder, USA) was used for developing the GUI. The user interface allows a scanner-independent reconstruction of MR data beginning from k-space including zero filling, algorithms for reducing phase wraps (homodyne filter or an image-space phase unwrapping algorithm [5]) and the creation of specific phase masks computed from phase images and their multiplication with the corresponding magnitude images. Interactive creation of minimum intensity projections and ROI-based data analysis, e.g., for the comparison of scans acquired under different conditions, are included. Results and Discussion: The software-tool visualizes image data containing phase and magnitude information as well as DICOM data. It enables a very flexible reconstruction of data. The intuitively designed graphical user interface allows physicians and medical technicians to quickly generate venograms and to flexibly set reconstruction and analysis parameters. It can be extended and modified easily according to the user's needs. Since the software is executed in the IDL-Virtual-Machine, a platform-independent usage without purchase of an IDL license is warranted. Conclusion: This software may help to make the wide range of possible applications of SWI more accessible to a larger number of users. References: [1] Reichenbach JR et al. NMR Biomed 2001; 14: 453–467. [2] Haacke EM et al. Image Anal Stereol 2002; 21: 107–113. [3] Barth M et al. Invest Radiol 2003; 38: 409–414. [4] Sedlacik J et al. Eur Radiol 2004;1 4(2, Suppl.2): 298. [5] Xu X et al. IEEE Transactions on Geosciences and Remote Sensing 1999; 37: 124–134.