[Image quality of CT angiography of coronary arteries depending on the degree of coronary calcification using a dual source CT scanner].
OBJECTIVE
To evaluate the influence of severe calcification on image quality of CT angiography (CTA) of coronary arteries acquired with dual source CT.


METHODS
171 dual source CTAs in spiral mode were evaluated. Depending on the Agatston score (CS), patients where divided into four subgroups (I: CS 0 - 200, II: CS 201 - 600, III: CS 601 - 1000, IV: CS > 1000). Image quality was evaluated by two independent, blinded readers using a three-stage scale and the image quality of each subgroup was also shown with the help of an image quality index (BQI). In addition, a comparison with coronary catheter angiography was undertaken in a subgroup.


RESULTS
Dual source CTA in spiral mode showed good image quality even in patients with Agatston scores of 601 - 1000 and > 1000. The four classes showed no significant difference in image quality. (BQI = 1,164 [I], BQI = 1,212 [II], BQI = 1,281 [III], BQI = 1,111 [IV]; p = 0,3145). The detailed analysis showed particularly good quality in patients with a heart rate < 75 bpm. The smaller subgroup of patients with CS > 200 and heart rates > 75 bpm showed a statistically significant reduction in image quality (BQI = 1,625; p = 0.0016). There were no gender differences in the image quality (p = 0.9881) although the calcium scores differed significantly in men (CS = 313 [+/- 449]) and women (CS = 145 [+/- 304]). The comparison with coronary catheter angiography showed a good correlation (92%).


CONCLUSIONS
CTA of coronary arteries performed with dual source CT in spiral mode provides good image quality even in patients with higher calcification scores. The reduction of heart rates > 75 bpm improves the image quality significantly in patients with higher calcification scores.
Artmann
A
A
Radiologie II, Klinikum Wels Grieskirchen, Osterreich. andreas.artmann@klinikumwegr.at
Enayati
S
S
Ratzenböck
M
M
Schwarz
M
M
Weber
T
T
Eber
B
B
D000368:Aged; D015901:Angiography, Digital Subtraction / Q000379:methods* / Q000592:standards*; D016477:Artifacts; D002114:Calcinosis / Q000000981:diagnostic imaging*; D006328:Cardiac Catheterization; D003287:Contrast Media / Q000008:administration & dosage; D017023:Coronary Angiography / Q000295:instrumentation / Q000379:methods* / Q000592:standards*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007479:Iopamidol / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015900:Radiography, Dual-Energy Scanned Projection / Q000295:instrumentation / Q000379:methods* / Q000592:standards*; D012015:Reference Standards; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D036542:Tomography, Spiral Computed / Q000295:instrumentation / Q000379:methods* / Q000592:standards*
D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol