Dose reduction and image quality assessment in 64-detector row computed tomography of the coronary arteries using an automatic exposure control system.
OBJECTIVE
To evaluate dose reduction and image quality in coronary 64-slice multidetector computed tomography using an automatic exposure control system (AECs).


METHODS
A total of 101 patients were divided into 4 groups. Tube current was 600 and 800 mAs in groups A and B and adapted at 600 and 800 quality-reference mAs using an AECs in groups C and D. Effective dose and organ-equivalent dose were evaluated. Image noise was quantified as standard deviation of air-space attenuation. Two observers assessed technical adequacy and image quality using a 4-point scale.


RESULTS
Effective dose ranged from 8.6 mSv (group C) to 15 mSv (group B) with significant dose reduction for examinations performed at 600 mAs (21.7%) and 800 mAs (29.4%). Contribution of organ-equivalent doses showed higher exposure for lungs (42%) and breast (22%). Noise was significantly higher in groups studied with AECs. Larger coronary segments resulted in higher image quality scores without differences between groups.


CONCLUSIONS
Automatic exposure control systems provides images of diagnostic quality with substantial dose reduction.
Francone
Marco
M
Department of Radiological Sciences, University of Rome La Sapienza, Rome, Italy. Marco.Francone@uniroma1.it
Di Castro
Elisabetta
E
Napoli
Alessandro
A
Bolzan
Chiara
C
Carbone
Iacopo
I
Bertoletti
Linda
L
Iuliano
Luigi
L
Catalano
Carlo
C
Passariello
Roberto
R
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography / Q000295:instrumentation* / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods