Influence of hemodynamic parameters on coronary artery attenuation with 320-detector coronary CT angiography.
OBJECTIVE
To investigate the relationship between cardiac output, end diastolic volume and the contrast enhancement in coronary CT angiography using 320-detector CT.


METHODS
A total of 38 patients underwent coronary CT angiography by using a 320-detector CT scanner (detector configuration, 320 × 0.5mm). The attenuation value of the ascending aorta at the level of the orifice of the left main trunk was measured. The cardiac output (CO), end diastolic volume (EDV) and stroke volume (SV) were measured by echocardiography. The EDV was normalized to the body surface area (BSA). The total blood volume injected from the left ventricle from the beginning of the contrast agent injection to the time of image acquisition was determined to be the total injected blood volume (TIV), which is a product of SV and the number of heart beats from the initiation of contrast agent injection to the scan.


RESULTS
There was a negative correlation between the attenuation of the ascending aorta and CO (r = -0.44, P = 0.0053). However, the negative correlation between the attenuation of the ascending aorta and TIV was stronger (r = -0.52, P = 0.0007). There was a negative correlation between the attenuation of the ascending aorta and EDV/BSA (r = -0.45, P = 0.0039).


CONCLUSIONS
In 320-detector CT, contrast enhancement in CCTA with a lesser amount of contrast medium decreases when cardiac output is high. Patients with larger EDV/BSA may also show decreased attenuation.
Department of Radiology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. tomizawa-tky@umin.ac.jp
Nobuo
N
Tomizawa
Shuhei
S
Komatsu
Masaaki
M
Akahane
Rumiko
R
Torigoe
Shigeru
S
Kiryu
Kuni
K
Ohtomo
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D002302:Cardiac Output; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013318:Stroke Volume; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media