The impact of spatial resolution and respiratory motion on MR imaging of atherosclerotic plaque.
OBJECTIVE
To examine the impact of spatial resolution and respiratory motion on the ability to accurately measure atherosclerotic plaque burden and to visually identify atherosclerotic plaque composition.


METHODS
Numerical simulations of the Bloch equations and vessel wall phantom studies were performed for different spatial resolutions by incrementally increasing the field of view. In addition, respiratory motion was simulated based on a measured physiologic breathing pattern.


RESULTS
While a spatial resolution of > or = 6 pixels across the wall does not result in significant errors, a resolution of < or = 4 pixels across the wall leads to an overestimation of > 20%. Using a double-inversion T2-weighted turbo spin echo sequence, a resolution of 1 pixel across equally thick tissue layers (fibrous cap, lipid, smooth muscle) and a respiratory motion correction precision (gating window) of three times the thickness of the tissue layer allow for characterization of the different coronary wall components.


CONCLUSIONS
We found that measurements in low-resolution black blood images tend to overestimate vessel wall area and underestimate lumen area.
Department of Medicine, Cardiovascular Division, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA.
Michael
M
Schär
Won Yong
WY
Kim
Matthias
M
Stuber
Peter
P
Boesiger
Warren J
WJ
Manning
René M
RM
Botnar
D001161:Arteriosclerosis / Q000175:diagnosis*; D003331:Coronary Vessels / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D012119:Respiration