Dramatic Dose Reduction in Three-Dimensional Rotational Angiography After Implementation of a Simple Dose Reduction Protocol

Pediatric Cardiology https://doi.org/10.1007/s00246-018-1943-3 ORIGINAL ARTICLE Dramatic Dose Reduction in Three-Dimensional Rotational Angiography After Implementation of a Simple Dose Reduction Protocol Savine C. S. Minderhoud1 Johannes M. P. J. Breur1 · Femke van der Stelt1 · Mirella M. C. Molenschot1 · Michel S. Koster2 · Gregor J. Krings1 · Received: 13 February 2018 / Accepted: 28 July 2018 © The Author(s) 2018 Abstract Previously, median effective dose (ED) of 1.6 mSv per three-dimensional rotational angiography (3DRA) has been reported. This study evaluated ED and image quality in 3DRA after implementation of a simple dose reduction protocol in pediatric catheterizations. Simple conversion factors between 3DRA ED and readily available parameters at the cathlab were determined. The dose reduction protocol consisted of frame reduction (60–30 frames/s (f/s)), active collimation of the X-ray beam, usage of a readily available low dosage program, and a pre-3DRA run check. EDs were calculated with Monte Carlo PCXMC 2.0. Three observers blindly assessed 3DRA image quality of the dose reduction and normal-dose cohort. Between October 2014 and October 2015, 84 patients (median age 4.3 years) underwent 100 3DRAs with a median ED of 0.54 mSv (0.12–2.2) using the dose reduction protocol. Median ED in the normal-dose cohort (17 3DRAs) was 1.6 mSv (1.2–4.9). Image quality in the dose reduction cohort remained excellent. Correlations between ED and dose area product (DAP) and ED and skin dose were found with a ρ of 0.82 and 0.83, respectively. ED exposure of the entire catheterization was reduced to 2.64 mSv. Introduction of a simple protocol led to 66% dose reduction in 3DRA and 79% in the entire catheterization. 3DRA image quality in this group remained excellent. In 3DRA ED correlates well with DAP and skin dose, parameters readily available at the cathlab. Keywords Catheterization · Rotational angiography · Radiation dose reduction · Effective dose Abbreviations 3DRA Three-dimensional rotational angiography DAP Dose area product ED Effective dose Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00246-018-1943-3) contains supplementary material, which is available to authorized users. * Savine C. S. Minderhoud 1 Department of Pediatric Cardiology, Wilhelmina Children’s Hospital, University Medical Center, Lundlaan 6, 3584 EA Utrecht, The Netherlands 2 Radiation Protection and Consultancy, NRG-Consultancy and Services, Westerduinweg 3, 1755 LE Petten, The Netherlands Introduction In pediatric cardiology imaging is essential for diagnostic and interventional purposes. For this reason, patients with congenital heart disease regularly and increasingly receive radiation over the years [1]. Radiation exposure during childhood is more harmful than during adulthood. Reasons for this are the longer life span children have and the more harmful effects radiation has on developing tissue. With increased radiation exposure, children’s lifetime cancer risks will increase [2–5]. Catheterizations contribute to the majority of radiation burden in patients with congenital heart disease [6]. Quite recently, three-dimensional rotational angiography (3DRA) has been added to the spectrum of image modalities. 3DRA is used for diagnostic and interventional reasons. 3DRA provides a real-time roadmap for anatomy-guided procedures and improves faster and simplified interventions with enhanced patients’ safety [7]. Conversion factors enabling simple estimation of effective 13 Vol.:(0123456789) Pediatric Cardiology dose (ED) for standard procedures such as 3DRA acquisition have not yet been published [8]. Many studies report dose area product (DAP), a value directly provided by the imaging system [9, 10], but this value does not quantify the radiation’s effect on patients. The effective radiation dose (ED) is the best indicator to assess the stochastic effects of radiation [3]. Furthermore, ED enables comparison between the effects of 3DRA and effects of other imaging modalities [3]. Many studies directly estimate ED from DAP [10–12]. However, the relation between DAP and ED for 3DRA has never been strongly confirmed [13]. A strong correlation will help to produce a simple formula to estimate the ED, which is more practical for daily use than the complex ED calculations. In 2014, Peters et al. have reported a median ED of 1.6 mSv per 3DRA in only 17 pediatric patients [14]. To limit the radiation burden, the ED should be reduced to a minimum with preservation of image quality. The ED might decrease with a few simple changes in the 3DRA protocol [2, 13, 14]. Therefore, the aim of the present study is (1) to calculate the EDs after implementation of a simple dose reduction protocol in a larger group of patients and compare the results with Peters et al., (2) to evaluate imaging quality of this protocol, and (3) to further explore the correlation between DAP and ED [14]. Materials and Methods Study Population Patients were eligible for inclusion if they were 0–18 years of age and had undergone a cardiac catheterization procedure with 3DRA acquisition at the Wilhelmina Children’s Hospital between October 2014 and October 2015. The institutional review board approved this study and no informed consent was required. Retrospective analysis of medical records and catheterization data was performed. Parameters collected include age, weight, height, body surface area (BSA), cardiac diagnosis, and type of intervention (if applicable). Patients were grouped according to their initial diagnosis. Patient characteristics of this low-dose cohort 3DRA were compared with a patient group previously reported, undergoing a normal-dose 3DRA [14]. Reasons for exclusion from ED calculation were incomplete rotation, wrong positioning of the patient, and insufficient contrast. As contrast absorbs radiation, insufficient contrast leads to less radiation exposure. 3DRAs made with a central venous catheter or because of a non-cardiac diagnosis were excluded from image quality assessment. 13 3DRA Image Acquisition 3DRAs were obtained using the Siemens Artis Zee biplane (Siemens, Forchheim, Germany) and reconstructions were transferred to the Leonardo workstation for post-processing with Syngo DynaCT Cardiac software. All procedures were performed under general anesthesia. Rapid atrial or ventricular pacing was performed in 88 of the 100 3DRAs. Pacing frequency was increased from 180/min upwards until a reduction of 50% of the systolic blood pressure was achieved. Contrast medium was administrated to the cardiac compartment prior to the region of interest meaning the right ventricle for pulmonary imaging and the left ventricle for aortic imaging. Contrast was diluted up to 60% with saline. Contrast was injected from 2 mL/s in 3 kg neonates up to 16 mL/s in 50 kg adolescents in case of a single injection site before start of 3DRA for 5 s. When multiple injection si (...truncated)