Radiation dose exposure of patients undergoing 320-row cardiac CT for assessing coronary angiography and global left ventricular function

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.

Long-Term Efficacy of a Mini-Course in Radiation-Reducing Techniques in Invasive Cardiology

“…ED values of multi-slice computed tomography coronary angiography (CTCA) with the use of retrospective ECG-gating -representing noninvasive CA -are reported to vary from 8 to 28 mSv [4, 20,21] and yield the considerable calculated LAR of cancer incidence for a representative 50-year-old subject with a range between 0.10 and 0.17 % for males and between 0.23 and 0.37 % for females [22]. The use of automatic dose control reduced the ED in chest scans by 36 % [23], and in conformity with actual recommendations [24], ECG-triggered, singleand two-heartbeat CTCA enabled lower EDs of 2.2 to 8.6 mSv, without affecting diagnostic performance [21,[25][26][27]. For the specific subgroup of non-obese patients with a low and stable heart rate, furthermore, values even on the submillisievert level for CTCA have been achieved [28].…”

Recent advances in cardiac computed tomography dose reduction strategies: a review of scientific evidence and technical developments

“…In combination with high gantry rotation speed/temporal resolution, these scanners allow single beat axial acquisition with a static table. [38][39][40][41] The image reconstruction algorithms used for CT image reconstruction can further influence the choice of scan factors and thus the associated radiation dose. Most modern CT scanners are increasingly employing sophisticated iterative reconstruction (IR) techniques as compared with the previously used filtered back projection (FBP) algorithms, which are less computationally demanding.…”

“…9 Various studies have reported radiation doses associated with the use of wide detector array MDCT scanners for CCTA ranging from 4.4 to 15 mSv. 9,38,39,41,78,79 In a single study with second-generation wide-volume 320-detector row MDCT, Chen et al 40 reported a substantially low radiation dose for CCTA examinations (0.9 mSv; interquartile range 0.6 to 1.7 mSv).…”

The Role of Left Atrial Imaging in the Management of Atrial Fibrillation

“…Image quality can be impaired with heart rates greater than 60 beats per minute and by irregular heart rhythms such as AF. Also of potential concern, CCT is associated with a small dose of radiation exposure 13,14 and may be contra-indicated in patients with allergies to iodinated contrast or significant renal impairment.…”