Published in:
01-06-2012 | Original Paper
Radiation dose exposure of patients undergoing 320-row cardiac CT for assessing coronary angiography and global left ventricular function
Authors:
Chien-Ming Chen, Yuan-Chang Liu, Chun-Chi Chen, Ming-Shien Wen, Chien-Fu Hung, Yung-Liang Wan
Published in:
The International Journal of Cardiovascular Imaging
|
Special Issue 1/2012
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Abstract
A 320-row multidetector CT provides the capability for prospective electrocardiogram (ECG)-gated coronary CT angiography (CTA) and tube current modulated cardiac function assessment (CFA). We assessed and compared the effective radiation dose of these two modes. On a prospective basis, we performed ECG-gated cardiac CT on 119 patients (87 were males). For heart rates (HRs) ≦65 beats/min (bpm), we used one-heartbeat acquisition and half-scan reconstruction. HRs from 66 to 79 bpm and ≧80 bpm were scanned with either two or three heartbeats acquisitions, respectively. We used two types of scans. One type was based on a prospective ECG-gated CTA mode and the other using a tube current modulated CFA mode covering an entire R–R interval. The mean BMI of patients was 25.4 (range 18.8–49.3). Fifty-one patients (42.9 %) underwent CFA scanning, while the remaining 68 (57.1 %) had CTA. The majority of patients completed the scan in a single heartbeat (59.7 %). The mean dose of CTA mode at 65–85 % phase window for one and two heartbeats was 3.68 mSv (2.40–7.23) and 8.61 mSv (6.76–10.60), respectively. The mean dose of CFA mode for a single heartbeat measurement with dose modulation (25 % dose for CFA, and 100 % dose during 65–85 % phase window for CTA) was 6.32 mSv (4.69–8.89). CTA with prospective ECG-gating allows for acceptable image quality and radiation dose. HR reduction is mandatory to minimize radiation exposure. Global left ventricle function can be assessed with a single heartbeat within an acceptable radiation dose.