Accelerated free breathing ECG triggered contrast enhanced pulmonary vein magnetic resonance angiography using compressed sensing

Background: To investigate the feasibility of accelerated electrocardiogram (ECG)-triggered contrast enhanced pulmonary vein magnetic resonance angiography (CE-PV MRA) with isotropic spatial resolution using compressed sensing (CS). Methods: Nineteen patients (59 +/- 13 y, 11 M) referred for MR were scanned using the proposed accelerated free breathing ECG-triggered 3D CE-PV MRA sequence (FOV = 340 x 340 x 110 mm(3), spatial resolution = 1.5 x 1.5 x 1.5 mm(3), acquisition window = 140 ms at mid diastole and CS acceleration factor = 5) and a conventional first-pass breath-hold non ECG-triggered 3D CE-PV MRA sequence. CS data were reconstructed offline using low-dimensional-structure self-learning and thresholding reconstruction (LOST) CS reconstruction. Quantitative analysis of PV sharpness and subjective qualitative analysis of overall image quality were performed using a 4-point scale (1: poor; 4: excellent). Results: Quantitative PV sharpness was increased using the proposed approach (0.73 +/- 0.09 vs. 0.51 +/- 0.07 for the conventional CE-PV MRA protocol, p < 0.001). There were no significant differences in the subjective image quality scores between the techniques (3.32 +/- 0.94 vs. 3.53 +/- 0.77 using the proposed technique). Conclusions: CS-accelerated free-breathing ECG-triggered CE-PV MRA allows evaluation of PV anatomy with improved sharpness compared to conventional non-ECG gated first-pass CE-PV MRA. This technique may be a valuable alternative for patients in which the first pass CE-PV MRA fails due to inaccurate first pass timing or inability of the patient to perform a 20-25 seconds breath-hold.