CT coronary angiography in atrial fibrillation: a comparison of radiation dose and diagnostic confidence with retrospective gatingvsprospective gating with systolic acquisition

Abstract

Cite this article as: Clayton B, Roobottom C, Morgan-Hughes G. CT coronary angiography in atrial fibrillation: a comparison of radiation dose and diagnostic confidence with retrospective gating vs prospective gating with systolic acquisition. Objective: To compare unmodulated, retrospective electrocardiographic (ECG) gating to prospective ECG gating with systolic acquisition for CT coronary angiography (CTCA) in patients with atrial fibrillation (AF), considering the radiation dose and the diagnostic confidence achieved with each technique. Methods: A retrospective service evaluation was conducted before and after prospective gating with systolic acquisition replaced retrospectively gated imaging for patients with AF undergoing CTCA at our institution. 25 consecutive patients were examined in each group. The scan parameters and radiation dose information had been collected in a prospective fashion. The image sets were read by blinded, expert readers who rated their diagnostic confidence using a 5-point Likert scale.Results: The radiation dose received by patients was significantly greater in the retrospectively gated group than those being scanned using prospective gating (21 vs 5.9 mSv, p , 0.01). The prospective gating technique was also associated with greater diagnostic confidence (mean, per-patient score 3.09 vs 3.78, p 5 0.02). Conclusion: Prospective gating with systolic acquisition appears to improve diagnostic confidence at a significantly reduced radiation dose compared with retrospective gating in patients with AF. Advances in knowledge: The use of prospective gating with systolic triggering significantly reduces the radiation exposure to patients in AF undergoing CTCA. The same protocol also appears to improve diagnostic confidence.

Predicting Left Atrial Appendage Thrombus from Left Atrial Volume and Confirmation by Computed Tomography with Delayed Enhancement

“…28 Prospectively gated CT image acquisition with systolic triggering may reduce the radiation exposure in patients with AF even during standard 64-row MDCT. 29 However, the delayedenhancement step in our protocol adds only <1 mSv to the total effective radiation dose, requires imaging of only the upper half of the heart, and is done prospectively and at low kilovoltage (typically 100 kVp). In the future, newer generations of dual-energy CT scanners may be used without ECG gating to differentiate between LAA thrombus and slow flow by measuring iodine concentrations in LAA filling defects.…”

Localized Aortic Root Dissection with a Superior Mesenteric Artery Aneurysm

“… 8 ) Moreover, ECG-gated CTA is affected by arrhythmia. 9 ) In the present case, frequent supraventricular premature contractions were observed, but the patient’s hemodynamics were stable. Therefore, TEE was chosen as a secondary imaging study for detecting aortic dissection.…”

Computed Tomography Imaging in Simulated Ongoing Cardiopulmonary Resuscitation: No Need to Switch Off the Chest Compression Device during Image Acquisition

“…A possible approach to reduce radiation exposure would be an artificially generated frequency-adapted ECG, which is provided by the ACC device and allows prospective gating. Several studies have shown that the latter can reduce the radiation dose of cardiac CT scans by 67.3% to 84.9% compared to retrospective gating [ 25 , 26 , 27 , 28 ]. This setup would also reduce the time required to prepare the patient prior to the examination itself.…”