[Reconstruction of coronary 64-multidetector-row computed tomography angiography in patients with atrial fibrillation: delete short RR intervals using electorocardiogram].

Background: The image qualities of coronary 64-multidetector-row computed tomography angiography (CCTA) in patients with atrial fibrillation (Afib) are often not enough. This study clarifies how to use electrocardiogram (ECG) -editing in Afib.

Methods: We performed CCTA (Aquilion 64 with beam pitch: 0.125, 0.35 s/r) in 33 patients (M/F=24/9, age: 71±9 yr, mean heart rate: 71±12 bpm) with Afib. We injected 5 mg of verapamil into the vein when the mean HR was ≥80 bpm. First, we reconstructed images after deleting short RR (<800, 750, 700, 650, or 600). Second, we reconstructed images in 4 different methods: (1) end-systolic images with Phase Navi (automatically selecting an optimal phase) (ES-Navi), (2) Mid-diastolic images with Phase Navi (MD-Navi), (3) Mid-diastolic images reconstructed by the "R+absolute time method" [Edit-MD (R+)], and (4) Mid-diastolic images reconstructed by the "R-absolute time method" [Edit-MD (R-)]. We reconstructed 1 and 2 without ECG-editing, and 3 and 4 were reconstructed after ECG-editing without a data deficit. The quality of the images was classified into 3 ranks: no artifact (3), mild artifact (2), and severe artifact (1).

Results: The image quality point of CCTA, reconstructed after deleting RR<750, was similar to RR<800, and RR<750 was even higher than that after deleting HR<600, 650, or 700. The mean image quality point of CCTA that was reconstructed by Edit-MD (R-) or Edit-MD (R+) was significantly higher than ES-Navi or MD-Navi.

Conclusion: The high image quality of CCTA could be reconstructed after deleting RR<750 in 76% or after deleting RR<800 in 70% of Afib. The reconstruction using Edit-MD (R-) or Edit-MD (R+) without a data deficit could provide a better quality CCTA than using PhaseNavi in Afib.