- Oral presentation
- Open Access
Improved left atrial imaging in atrial fibrillation patients using novel ECG-gated vs. conventional non-gated cardiac MRA
© Sheffer et al; licensee BioMed Central Ltd. 2013
- Published: 30 January 2013
- Atrial Fibrillation
- Pulmonary Vein
- Left Atrium
- Atrial Fibrillation Patient
- Pulmonary Vein Stenosis
In patients undergoing atrial fibrillation (AF) procedures, imaging of the left atrium (LA) and pulmonary veins (PV) is important for pre-ablation planning and to identify post ablation complications. Conventional MRA protocols use first-pass, non-gated sequences that require long breath-holds. Quality of non-gated MRA's can be challenging in sick or sedated patients. We developed a novel ECG-gated, respiratory navigated MRA sequence less dependent on patient compliance, which yields better clarity of LA anatomy.
Eighty patients with AF underwent either conventional non-gated (n=40) vs. novel ECG-gated (n=40) MRA on a 3T Verio scanner (Siemens, Erlangen, Germany). All MRA's were performed using 0.1 mmol/kg Multihance (Bracco Diagnostics Inc., Princeton, NJ). A novel ECG-gated, respiratory navigated MRA was developed using 3D saturation recovery prepared, GRE sequence with fast contrast injection (half dose, 1.0 mL/sec) followed by slow infusion (half dose, 0.1 mL/sec). Saturation pulse was applied every heart beat and fat saturation was applied immediately before data acquisition during LA diastole. Additional scan parameters were: axial imaging volume, FOV =400x400x110, voxel size=1.25x1.25x2.5 mm, TR/TE=2.8/1.3ms, flip angle=15 degrees, TI=250ms, phase encoding direction: left to right. Typical scan time was 3-5 minutes.
Conventional non-gated MRA were performed with contrast injection rate 2.0 mL/sec and continuous data acquisition during single breath-hold (14 sec.). Scan parameters included: axial imaging volume, FOV=400x263x120 mm, voxel size=1.25x1.25x2.5, TR/TE=2.8/1.1ms, flip angle=27 degrees.
ECG-gated MRA scored better than non-gated MRA in all categories. Quality of contrast for ECG-gated MRA averaged 3.18 vs. 2.63 quality score (QS; p-value < 0.0001) in the non-gated cohort. Border sharpness scored 3.08 vs. 2.35 QS (p-value < 0.0001) respectively. Chamber detail was also assessed with specific anatomical positions, which all yielded superiority of ECG-gated MRA (pulmonary veins 3.04 vs. 2.35 QS (p-value < 0.0001); left atrial appendage 3.11 vs. 2.25 QS (p-value < 0.0001); left atrium 3.08 vs. 2.35 QS (p-value < 0.0001).
ECG-gated MRA improves image quality with better border sharpness and anatomical detail compared to conventional non-gated MRA. These advantages may translate into improved diagnostics in AF patients including detection of PV stenosis or following LA remodeling post-ablation.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.