Rapid and complete coronary arterial tree visualization with magnetic resonance imaging: feasibility and diagnostic performance

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Abstract
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 (1.2×1.2×1.4 mm3) with coverage of the whole heart [steady-state free precession (SSFP); TR/TE/flip angle: 5.3 ms/2.6 ms/90°; 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.