Characterizing radial undersampling artifacts for cardiac applications

Beth Israel Deaconess Medical Center and Harvard Medical School, Department of Medicine, Cardiovascular Division, Boston, Massachusetts 02215, USA.
Magnetic Resonance in Medicine (Impact Factor: 3.4). 02/2006; 55(2):396-403. DOI: 10.1002/mrm.20782
Source: PubMed

ABSTRACT The undersampled radial acquisition has been widely employed for accelerated (by a factor R = N(r)/N(p)) cardiac imaging, but the resulting reduction in image quality has not been well characterized. This investigation presents a method of measuring these artifacts through synthetic undersampling of high SNR images (SNR > or = 30). After validating the method in phantoms, the method was applied to a study of short-axis, long-axis, and coronary MRI imaging in healthy subjects. For 60 projections (60 N(p)), the total artifact is approximately 10% for short and long-axis imaging (R = 2.1) and approximately 15% for coronary MRI (R = 3.7). For 60 N(p), the SD of artifact in the region of the heart is 2% for short- and long-axis imaging (R = 2.1) and 3.5% for coronary MRI (R = 3.7). The artifact content is less in the region of the heart than in the periphery. The artifact is very reproducible among subjects for standard views. A study of coronary MRI at progressively fewer projections (at constant scan time) showed that right coronary MRI images were acceptable if total artifact was <6.5% of image content (N(p) > 120, R = 2.1).

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