What is the best contrast injection protocol for 64-row multi-detector cardiac computed tomography?
OBJECTIVE
To determine the optimal contrast injection protocol for 64-MDCT coronary angiography.


METHODS
One hundred and fifty consecutive patients scheduled to undergo retrospectively electrocardiographically gated 64-MDCT. Each 30 patients were assigned to use a different contrast protocol: group 1: uniphasic protocol (contrast injection without saline flush); group 2: biphasic protocol (contrast injection with saline flush); group 3A, 3B and 3C: triphasic protocol (contrast media+different saline diluted contrast media+saline flush). Image quality scores and artifacts were compared and evaluated on both transaxial and three-dimensional coronary artery images among each contrast protocol.


RESULTS
Among the triphasic protocol groups, group 3A (30%:70% contrast media-saline mixture was used in second phase) used the least contrast media and had the least frequency of streak artifacts, but there were no significant differences in coronary artery attenuation, image quality, visualization right and left heart structures. Among the uniphasic protocol group (group 1), biphasic protocol group (group 2) and triphasic protocol subgroup (group 3A), there were no significant differences in image quality scores of coronary artery (P=0.18); uniphasic protocol group had the highest frequency of streak artifacts (20 cases) (P<0.05) and had the most amount contrast media (67.0+/-5.3 ml); biphasic protocol group had the least amount of contrast media (59.9+/-4.9 ml) (P<0.05) and had the highest attenuation of left main coronary artery and right coronary artery (P<0.01), but had the least amount of clear visualization right heart structure (6 cases); triphasic protocol group (group 3A) had the most amount of clear visualization right heart structures (29 cases) were the most among the three groups (P<0.05).


CONCLUSIONS
Biphasic protocol are superior to the traditional uniphasic protocols for using the least total contrast media, having the least Streak artifacts and without image quality degradation. However, it is also important to visualize the right atrium and ventricle, so triphasic protocol (30%:70% contrast media-saline mixture was used in second phase) should be used for 64-MDCT coronary CT angiography.
Lu
Jin-guo
JG
Department of Radiology, Cardiovascular Institute and Fuwai Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, 167 Beilishi Road, Beijing, China.
Lv
Bin
B
Chen
Xiong-biao
XB
Tang
Xiang
X
Jiang
Shi-liang
SL
Dai
Ru-ping
RP
D000328:Adult; D000368:Aged; D016477:Artifacts; D003287:Contrast Media / Q000008:administration & dosage*; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D021621:Imaging, Three-Dimensional; D007267:Injections; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014683:Vena Cava, Superior / Q000000981:diagnostic imaging
D003287:Contrast Media