Aims: Current imaging of the coronary arteries with magnetic resonance coronary angiography (MRCA) is restricted to limited coverage of the coronary arterial tree and requires complex planning. We present and evaluate a rapid, single-scan MRCA approach with complete coverage of the coronary arterial tree.
Methods and results: Fifty-five consecutive patients with suspected coronary artery disease underwent free-breathing, navigator-gated MRCA using a single three-dimensional volume with transversal slice orientation and nearly isotropic spatial resolution (1.2 x 1.2 x 1.4 mm(3)) with coverage of the whole heart [steady-state free precession (SSFP); TR/TE/flip angle: 5.3 ms/2.6 ms/90 degrees ; Philips Intera CV 1.5T]. The acquisition duration per heart beat was individually adapted to the cardiac rest period. Correction of respiratory motion was done using a patient-specific affine prospective navigator technique (two navigator beams: cranio-caudal position on the dome of the right hemidiaphragm and anterior-posterior position on the right chest wall; gating window 10 mm). The diagnostic performance of MRCA in detecting significant coronary stenoses was evaluated against X-ray angiography as the standard of reference (32 patients) using a 16-segment model. Effective scan duration was 18+/-6 min (navigator efficiency: 68+/-14%). In all examinations, the main epicardial vessels [left anterior descending artery (LAD), left circumflex artery (LCX), and right coronary artery (RCA)], including their distal segments and major side branches (number of visible side branches: LAD, 2.0+/-0.9; LCX, 1.5+/-0.6; RCA, 2.3+/-0.9), were reliably visualized. Eighty-three per cent of all coronary segments were evaluable; sensitivity, specificity, and diagnostic accuracy were 78, 91, and 89%, respectively.
Conclusion: The combination of an imaging sequence with an intrinsically high contrast (SSFP) and a sophisticated navigator technique (affine transformation) resulted in high quality, high resolution imaging of the whole coronary arterial tree within a short examination duration. Robustness and diagnostic accuracy may allow for a routine application in the near future.