Characterizing radial undersampling artifacts for cardiac applications.
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).
Peters
Dana C
DC
Beth Israel Deaconess Medical Center and Harvard Medical School, Department of Medicine, Cardiovascular Division, Boston, Massachusetts 02215, USA. dcpeters@bidmc.harvard.edu
Rohatgi
Pratik
P
Botnar
René M
RM
Yeon
Susan B
SB
Kissinger
Kraig V
KV
Manning
Warren J
WJ
D016477:Artifacts; D006321:Heart / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging