Comparative study with a moving heart phantom of the impact of temporal resolution on image quality with two multidetector electrocardiography-gated computed tomography units.
OBJECTIVE
The objective of this study was to compare the temporal resolution-related image quality of electrocardiography-gated images acquired with two multidetector computed tomography (CT) units with a moving heart phantom, at similar fixed heart rates, using half-scan and multisector acquisition modes.


METHODS
An adjustable moving heart phantom (Limbsandthings, Horfield, Bristol, UK) was used. Specific heart rates (47, 55, 64, 66, 69, and 73 beats per minute [bpm]) were chosen. On a General Electric CT unit (LightSpeed Plus; General Electric Medical Systems, Milwaukee, WI), retrospective half-scan and multisector mode protocols were performed. On a Siemens CT unit (Somatom Volume Zoom; Siemens, Forchheim, Germany), a retrospective half-scan mode was performed at 47, 55, and 64 bpm, and a two-sector mode was performed at 66, 69, and 73 bpm. Reformatted maximum intensity projection images were qualitatively compared and related to their temporal resolution.


RESULTS
Half-scan mode protocols provided similar good results with both CT units up to 55 bpm. The two-sector mode improved image quality compared with the half-scan mode. High temporal resolution with the multisector mode provided the best results.


CONCLUSIONS
For coronary artery imaging, acquisition protocols that provide the highest temporal resolution are mandatory. The multisector mode is one technique that allows high temporal resolution but may be clinically inappropriate at heart rates below 65 bpm or when heart rate variation is observed during scan time.
Wicky
Stephan
S
Department of Radiology, Massachusetts General Hospital, Boston, MA 02114, USA. swicky@partners.org
Rosol
Michael
M
Hoffmann
Udo
U
Graziano
Michael
M
Yucel
Kent E
KE
Brady
Thomas J
TJ
D017023:Coronary Angiography; D004562:Electrocardiography; D006321:Heart / Q000000981:diagnostic imaging; D006339:Heart Rate; D006801:Humans; D008955:Models, Cardiovascular; D019047:Phantoms, Imaging; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods