Influence of heart rate on coronary calcium scores: a multi-manufacturer phantom study

Abstract

To evaluate the influence of heart rate on coronary calcium scores (CCS) using a dynamic phantom on four high-end computed tomography (CT) systems from different manufacturers. Artificial coronary arteries were moved in an anthropomorphic chest phantom at linear velocities, corresponding to < 60, 60-75 and > 75 beats per minute (bpm). Data was acquired with routinely used clinical protocols for CCS on four high-end CT systems (CT1-CT4). CCS, quantified as Agatston and mass scores were compared to reference scores at < 60 bpm. Influence of heart rate was assessed for each system with the cardiac motion susceptibility (CMS) Index. At increased heart rates (> 75 bpm), Agatston scores of the low mass calcification were similar to the reference score, while Agatston scores of the medium and high mass calcification increased significantly up to 50% for all CT systems. Threefold CMS increases at > 75 bpm in comparison with < 60 bpm were shown. For medium and high mass calcifications, significant differences in CMS between CT systems were found. Heart rate substantially influences CCS for high-end CT systems of four major manufacturers, but CT systems differ in motion susceptibility. Follow-up CCS CT scans should be acquired on the same CT system and protocol, and preferably with comparable heart rates.

Best practice for the nuclear medicine technologist in CT-based attenuation correction and calcium score for nuclear cardiology

“…Prospective ECG triggering is used in patients with low and stable heart rates (< 60 bpm). This technique assumes that the interval between two R waves remains stable for the entire duration of the acquisition (van der Werf et al 2018 ). Modern CT scanners also provide the option to skip an acquisition in prospective ECG triggering mode if an extra systole occurs.…”

Classification of moving coronary calcified plaques based on motion artifacts using convolutional neural networks: a robotic simulating study on influential factors

“…It has been demonstrated that plaque classification also depends on the density and size, where relatively small and soft calcified plaques may remain undetected [32]. Van der Werf et al found that at an increased heart rate, the Agatston scores of low-density calcified plaques were similar to the reference scores but that the Agatston scores of medium-and high-density calcified plaques were increased by up to 50% [11]. In our study, all CNN architectures gained the highest classification accuracy for plaques with low density.…”

“…Whether using ECG-triggered cardiac or non-triggered chest scans, an accompanied limitation is the presence of motion artifacts, which considerably decreases the accuracy of CAC detection and quantification [11]. To decrease the motion artifacts in ECG-triggered CT, the temporal resolution should be shorter than 10% of one cardiac cycle time [12].…”

Fully automated quantification method (FQM) of coronary calcium in an anthropomorphic phantom

“… 21 Electrocardiography trigger output was used to ensure that acquisition was done during linear motion of the calcifications. 13 …”

“… 10 , 11 , 12 Moreover, CAC scores can vary greatly due to motion of the coronary arteries during the scan phase of a CAC scoring CT acquisition. 13 In order to study these differences, their possible impact on clinical outcome, and to optimize acquisition protocols, dedicated coronary calcium phantoms are frequently used. In the well‐established international standard developed for CAC quantification by McCollough and colleagues, a commonly evaluated commercially available anthropomorphic phantom was used (thorax and CCI phantom, QRM, Möhrendorf, Germany).…”