Validation of contrast-enhanced time-resolved magnetic resonance angiography in pre-ablation planning in patients with atrial fibrillation: comparison with traditional technique
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Bolus timing is critical to optimal magnetic resonance angiography (MRA) acquisitions but can be challenging in some patients. Our purpose was to evaluate whether contrast-enhanced time-resolved magnetic resonance angiography (TR-MRA), a dynamic multiphase sequence that does not rely on bolus timing, is a viable alternative method to conventional 3D fast-long angle shot contrast-enhanced magnetic resonance angiography (CE-MRA). Coronal subtracted conventional CE-MRA images in 50 consecutive patients presenting for pre-atrial fibrillation ablation pulmonary venous (PV) mapping were compared with 50 TR-MRA images performed in 50 subsequent patients. The TR-MRA protocol was modified to optimize spatial resolution with slightly reduced temporal resolution (6.1 s scan time). Three experienced readers evaluated each scan’s image quality and relative left atrial (LA) opacification based on a 4-point scale and diagnostic PV visualization in a binary fashion. Additionally, LA signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and PV dimensions were measured for both techniques. TR-MRA had significantly higher overall image quality (3.10 ± 0.69 vs. 2.42 ± 0.69, p < 0.0001), and LA opacification scores (3.33 ± 0.70 vs. 2.15 ± 1.13, p < 0.0001) compared to CE-MRA. The proportion of diagnostically visualized pulmonary veins was 137/150 (91%) in the CE-MRA group vs. 147/150 (98%) with TR-MRA (p = 0.010). Both SNR and CNR were higher with TR-MRA vs. CE-MRA (277.9 ± 48.9 vs. 106.8 ± 41, p = 0.002 and 100.3 ± 41.7 vs. 70.7 ± 48.0, p = 0.002, respectively). Inter-reader variance of individual PV measurements for each of the MR techniques ranged between 0.62 and 1.47 mm and the ICC for vein measurements was higher with TR-MRA (range: 0.62–0.81) compared to CE-MRA (range: 0.47–0.64). TR-MRA, modified to maximize spatial resolution, offers an alternative method for performing high quality MRA examinations in patients with AF. TR-MRA offers greater overall image quality, PV visualization, and similarly reproducible PV measurements compared to traditional CE-MRA, without the challenges of proper bolus timing.
KeywordsAtrial fibrillation Catheter ablation Contrast-enhanced magnetic resonance angiography Time-resolved magnetic resonance angiography
Magnetic resonance angiography
Contrast-enhanced magnetic resonance angiography
Time-resolved magnetic resonance angiography
Contrast to noise ratio
Signal to noise ratio
Regions of interest
Right superior pulmonary vein
Right inferior pulmonary vein
Left superior pulmonary vein
Left inferior pulmonary vein
The study was funded by the National Institutes of Health (Grant Nos. K23HL089333 and R01HL116280) as well as by a Biosense Webster grant to Dr Nazarian; the Roz and Marvin H. Weiner and Family Foundation; the Dr. Francis P. Chiaramonte Foundation; Marilyn and Christian Poindexter; and the Norbert and Louise Grunwald Cardiac Arrhythmia Research Fund. Funding bodies had no role in the design of the study; collection, analysis, or interpretation of data; or in writing the manuscript.
Compliance with ethical standards
Conflict of interest
Dr. Nazarian has received research grant funding from Biosense Webster during the conduct of the study. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
The Johns Hopkins Institutional Review Board (JH-IRB) approved the study and retrospective study data was obtained under a HIPPA compliant waiver of consent.
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