An Optimal Radial Profile Order Based on the Golden Ratio for Time-Resolved MRI

• Published in: IEEE transactions on medical imaging 2007-01, Vol.26 (1), p.68-76
• Main Authors: Winkelmann, S., Schaeffter, T., Koehler, T., Eggers, H., Doessel, O.
• Format: Article
• Language: English
• Subjects: Algorithms; Biomedical engineering; Biomedical imaging; Europe; Filters; Image Enhancement - methods; Image Interpretation, Computer-Assisted - methods; Image reconstruction; Image resolution; Imaging, Three-Dimensional - methods; Information Storage and Retrieval - methods; Kinetic theory; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Projection reconstruction; radial signal-to-noise ratio (MRI); real-time imaging; Reproducibility of Results; Sensitivity and Specificity; Signal to noise ratio; Spatial resolution; Studies; time-resolved imaging
• ISSN: 0278-0062; 1558-254X
• DOI: 10.1109/TMI.2006.885337

In dynamic magnetic resonance imaging (MRI) studies, the motion kinetics or the contrast variability are often hard to predict, hampering an appropriate choice of the image update rate or the temporal resolution. A constant azimuthal profile spacing (111.246deg), based on the Golden Ratio, is investigated as optimal for image reconstruction from an arbitrary number of profiles in radial MRI. The profile order is evaluated and compared with a uniform profile distribution in terms of signal-to-noise ratio (SNR) and artifact level. The favorable characteristics of such a profile order are exemplified in two applications on healthy volunteers. First, an advanced sliding window reconstruction scheme is applied to dynamic cardiac imaging, with a reconstruction window that can be flexibly adjusted according to the extent of cardiac motion that is acceptable. Second, a contrast-enhancing k-space filter is presented that permits reconstructing an arbitrary number of images at arbitrary time points from one raw data set. The filter was utilized to depict the T1-relaxation in the brain after a single inversion prepulse. While a uniform profile distribution with a constant angle increment is optimal for a fixed and predetermined number of profiles, a profile distribution based on the Golden Ratio proved to be an appropriate solution for an arbitrary number of profiles