[Imaging of the coronary arteries by means of multislice helical CT: optimization of image quality with multisegmental reconstruction and variable gantry rotation time].
OBJECTIVE
To evaluate the potential of multisegmental reconstruction and variable gantry rotation time for reducing motion-induced artifacts in coronary artery imaging by multislice helical CT.


METHODS
The data sets of 20 patients (8 with HR < 60 bpm, 12 with HR > 60 bpm) were analyzed. The patients underwent multislice helical CT (Aquilion 8, Toshiba, Otawara, Japan) using the following parameters: 0.5 mm slice thickness, 250 mA, 120 kV, pitch of 0.25 and variable gantry rotation times of 400, 500, or 600 msec. Images were generated by halfscan and multisegmental reconstruction. In 9 coronary segments of each patient, the presence and severity of motion artifacts were assessed and graded on a scale between 5 (no artifacts) and 1 (heaviest artifacts).


RESULTS
Diagnostically relevant motion artifacts were rare at low heart rates (< 60 bpm) for both types of image reconstruction (4 % of all segments). Higher heart rates (> 60 bpm) were associated with an increase in motion artifacts on halfscan reconstructions (33% of all segments, p < 0.05) but not on multisegmental reconstructions (4% of all segments). At low heart rates mean image quality did not differ between multisegmental and halfscan reconstruction (4.28 +/- 0.37 vs. 4.22 +/- 0.41; p > 0.05), whereas at higher heart rates image quality was better for multisegmental reconstruction than for halfscan reconstruction (4.23 +/- 0.47 vs. 3.11 +/- 0.63; p < 0.05).


CONCLUSIONS
Multisegmental reconstruction with variable gantry rotation times suppresses motion artifacts and thus improves assessment of the coronary arteries in patients with higher heart rates.
Lembcke
A
A
Institut für Radiologie, Universitätsklinikum Charité, Campus Charité Mitte, Humboldt-Universität zu Berlin. Alexander.Lembcke@gmx.de
Rogalla
P
P
Mews
J
J
Blobel
J
J
Enzweiler
C N
CN
Wiese
T H
TH
Hermann
K-G A
KG
Hamm
B
B
D016477:Artifacts; D017023:Coronary Angiography / Q000379:methods*; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D004562:Electrocardiography; D006339:Heart Rate; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012984:Software; D036542:Tomography, Spiral Computed / Q000379:methods*