Background: Usually, the pulmonary venous and left atrial (PV-LA) anatomy is assessed with contrast-enhanced computed tomographic imaging for catheter ablation of atrial fibrillation (AF). A non-contrast-enhanced magnetic resonance (MR) imaging method has not been established. Three-dimensional balanced steady-state free precession (3D b-SSFP) sequences cannot visualize the PV-LA anatomy simultaneously because of the signal intensity defect of pulmonary veins. We compared two-dimensional (2D) b-SSFP sequences with 3D b-SSFP sequences in depicting the PV-LA anatomy with non-contrast-enhanced MR imaging for AF ablation.
Methods: Eleven healthy volunteers underwent non-contrast-enhanced MR imaging with 3D b-SSFP and 2D b-SSFP sequences. The MR images were reconstructed on the 3D PV-LA surface image. Two experienced radiological technicians independently scored the multiplanar reformatted (MPR) images on a scale of 1-4 (from 1, not visualized, to 4, excellent definition). The overall score was a sum of 5 segments (LA and 4 PVs).
Results: In the 2D b-SSFP method, MR imaging was successfully performed, and the 3D PV-LA surface image was precisely reconstructed in all healthy volunteers. The image score was significantly higher in the 2D b-SSFP method compared to the 3D b-SSFP method (19 [19; 20] vs. 12 [11; 15], p=0.004, for both observers). No PV signal intensity defects occurred in the 2D b-SSFP method.
Conclusions: The 2D b-SSFP sequence was more useful than the 3D b-SSFP sequence in adequately depicting the PV-LA anatomy.
Keywords: 3D, three-dimensional; AF, atrial fibrillation; Atrial fibrillation; Balanced SSFP; CT, computed tomography; FA, flip angle; FOV, field of view; LAA, left atrial appendage; LSPV, left superior pulmonary vein; Left atrium; MPR, multiplanar reformatted; MR, magnetic resonance; Magnetic resonance imaging; PV–LA, pulmonary venous and left atrial; Pulmonary vein; SENSE, sensitivity encoding; TE, echo time; TR, repetition time; b-SSFP, balanced steady-state free precession.