Feasibility of low-dose coronary CT angiography: first experience with prospective ECG-gating.
OBJECTIVE
To determine the feasibility of prospective electrocardiogram (ECG)-gating to achieve low-dose computed tomography coronary angiography (CTCA).


RESULTS
Forty-one consecutive patients with suspected (n = 35) or known coronary artery disease (n = 6) underwent 64-slice CTCA using prospective ECG-gating. Individual radiation dose exposure was estimated from the dose-length product. Two independent readers semi-quantitatively assessed the overall image quality on a five-point scale and measured vessel attenuation in each coronary segment. One patient was excluded for atrial fibrillation. Mean effective radiation dose was 2.1 +/- 0.6 mSv (range, 1.1-3.0 mSv). Image quality was inversely related to heart rate (HR) (57.3 +/- 6.2, range 39-66 b.p.m.; r = 0.58, P < 0.001), vessel attenuation (346 +/- 104, range 110-780 HU; r = 0.56, P < 0.001), and body mass index (26.1 +/- 4.0, range 19.1-36.3 kg/m(2); r = 0.45, P < 0.001), but not to HR variability (1.5 +/- 1.0, range 0.2-5.1 b.p.m.; r = 0.28, P = 0.069). Non-diagnostic CTCA image quality was found in 5.0% of coronary segments. However, below a HR of 63 b.p.m. (n = 28), as determined by receiver operator characteristic curve, only 1.1% of coronary segments were non-diagnostic compared with 14.8% with HR of >63 b.p.m. (P < 0.001).


CONCLUSIONS
This first experience documents the feasibility of prospective ECG-gating for CTCA with diagnostic image quality at a low radiation dose (1.1-3.0 mSv), favouring HR <63 b.p.m.
Husmann
Lars
L
Department of Medical Radiology and Cardiovascular Center, University Hospital Zurich, Raemistr. 100, CH-8091 Zurich, Switzerland.
Valenta
Ines
I
Gaemperli
Oliver
O
Adda
Olivier
O
Treyer
Valerie
V
Wyss
Christophe A
CA
Veit-Haibach
Patrick
P
Tatsugami
Fuminari
F
von Schulthess
Gustav K
GK
Kaufmann
Philipp A
PA
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D017023:Coronary Angiography / Q000379:methods* / Q000592:standards; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D004562:Electrocardiography / Q000379:methods; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000592:standards