Cardiac three-dimensional rotational angiography can be performed with low radiation dose while preserving image quality

CLINICAL RESEARCH Europace (2013) 15, 1718–1724 doi:10.1093/europace/eut140 Ablation for atrial fibrillation Cardiac three-dimensional rotational angiography can be performed with low radiation dose while preserving image quality Stijn De Buck†, Becker S.N. Alzand†, Jean-Yves Wielandts, Christophe Garweg, Thomas Phlips, Joris Ector, Dieter Nuyens, and Hein Heidbuchel* Department of Cardiovascular Sciences, Section of Arrhythmology, University Hospital Gasthuisberg, University of Leuven, Herestraat 49, B-3000 Leuven, Belgium, Europe Received 20 January 2013; accepted after revision 25 April 2013; online publish-ahead-of-print 31 May 2013 Aims The effective radiation dose (ED) of three-dimensional rotational angiography (3DRA) is 5–8 mSv, leading to reticence on its use. We evaluated the potential of 3DRA with a reduced number of frames (RNF) and a reduced dose per frame. ..................................................................................................................................................................................... Methods Three-dimensional rotational angiography was performed in 60 patients (52.5 + 9.6 years, 16 females) referred for aband results lation in the right (RA; n ¼ 10) and left atrium (LA; n ¼ 50). In a simulation group (n ¼ 20), the effect of dropping frames from a conventional 248 frames 3DRA LA acquisition was simulated. In a prospective group (n ¼ 40), RNF 3DRA were acquired of LA (n ¼ 30) and RA (n ¼ 10) with 67 frames (0.24 Gy/frame) and 45 frames (0.12 mGy/frame), respectively. Accuracy was evaluated qualitatively and quantitatively. Effective radiation dose was determined by Monte Carlo simulation on every frame. In the simulation group, surface errors increased minimally and non-significantly when reducing frames from 248 to 124, 83, 62, 50, 42, and 31: 0.49 + 0.51, 0.52 + 0.46, 0.61 + 0.49, 0.62 + 0.47, 0.71 + 0.48, and 0.81 + 0.47 mm, respectively (Pearson coefficient 0.20). All 3D LA images were clinically useful, even with only 31 frames. In the prospective group, good or optimal 3D image quality was achieved in 80% of LA and all of RA reconstructions. These accurate models were obtained with ED of 2.6 + 0.4 mSv for LA and 1.2 + 0.5 mSv for RA. ..................................................................................................................................................................................... Conclusion Three-dimensional rotational angiography is possible with a significant reduction in ED (to the level of prospectively gated cardiac computed X-ray tomography) without compromising image quality. Low-dose 3DRA could become the preferred online 3D imaging modality for pulmonary vein isolation and other anatomy-dependent ablations. ----------------------------------------------------------------------------------------------------------------------------------------------------------Keywords Radiation risk † Catheter ablation † Rotational angiography † Atrial fibrillation † Imaging † Effective dose Introduction Comprehensive anatomical visualization is essential during ablation of many cardiac arrhythmias. This is especially true for pulmonary vein isolation (PVI), where the anatomically determined region surrounding the pulmonary vein (PV) is targeted for energy delivery, but also applies for other arrhythmia substrates. Anatomical reconstruction by electroanatomical mapping is often inaccurate. Therefore, merging with highly detailed three-dimensional (3D) patient-specific anatomical models is often sought.1 – 3 Also overlay of classical fluoroscopic imaging with 3D models has been described as an approach to assist ablation: the fine details about the PV orifices † and the ridge between left atrial (LA) appendix and the left PVs, allows for accurate planning and execution of the ablation lines.4 Three-dimensional imaging of the cardiac chambers can be performed pre-interventionally by magnetic resonance imaging5,6 or computed X-ray tomography (CT).4,7 More recently, also 3D rotational angiography (3DRA) has been introduced, enabling 3D imaging during the intervention which offers advantages in terms of patient comfort, logistics, and accuracy of registration.1,8,9 Nevertheless, its effective radiation dose (ED) is estimated between 5 and 8 mSv.10 Although the ED is lower than with retrospectively gated CT (ED of 13.8 mSv)11 and comparable with prospectively gated cardiac CT (ED around 4.5 mSv),11 it is higher than prospectively Both authors contributed equally to this study. * Corresponding author. Tel: +32 16 34 42 48; fax: +32 16 34 42 40, Email: Published on behalf of the European Society of Cardiology. All rights reserved. & The Author 2013. For permissions please email: . Reduced dose rotational angiography What’s new? † Three-dimensional cardiac rotational angiography (3DRA) can be performed with three to six times less radiation exposure compared with standard protocols, without compromising highly detailed image quality. † This was achieved by both reducing the number of frames taken during the rotational acquisition, and by reducing the energy per frame. † Data from a first series of simulated 3D reconstructions (n ¼ 20), were later confirmed in a prospective group (n ¼ 40), in whom 3DRA were acquired of the left (n ¼ 30) and right atrium (n ¼ 10), with 67 frames (0.24 Gy/frame) and 45 frames (0.12 mGy/frame), respectively. † Hence, the effective radiation dose was reduced to the level of state-of-the-art prospectively gated cardiac computed X-ray tomography imaging protocols, i.e. 2.6 + 0.4 mSv for left and 1.2 + 0.5 mSv for right atrium. † Using such low-dose protocols is of benefit to all patients in whom a 3DRA is done, and should be recommended to improve long-term safety. gated, high-pitch cardiac CT (ED of 0.9 mSv).12 Since this radiation dose has to be added to the radiation during the ablation itself, some consider this extra radiation dose undefendable. We wanted to explore ways to reduce the radiation dose of 3DRA while preserving its high anatomical detail during imaging the left or right atrium (LA; RA). We evaluated the impact (i) of a reduced number of frames (RNF) and (ii) of a reduced detector entrance dose per frame on image quality of 3DRA and calculated the respective patient EDs. Methods Study population and design Three-dimensional rotational angiography was performed in 60 patients (52.5 + 9.6 years, 16 females) referred for ablation of arrhythmias in the RA (n ¼ 10) or LA (n ¼ 50). Mean patient height, weight, and body mass index (BMI) were 177 + 9.8 cm, 82.6 + 14.6 kg, and 26.1 + 3.7 kg/m2, respectively. Patients comprised two groups: a simulation group (n ¼ 20) and a prospective group (n ¼ 40). In the simulation group, the effect of dropping an increasing number of frames from a standard 248 frames 3DRA LA acquisition was simulated: the resulting LA surface models were qualitatively and quantitatively compared with the origina (...truncated)