The feasibility of whole heart magnetic resonance coronary angiography to determine the course of anomalous coronary arteries

Background: Anomalous coronaries are present in 1% of the population and may be associated with sudden death, particularly if the aberrant vessel courses between the aorta and right ventricular outflow tract (RVOT) to supply the left coronary distribution. Although the course of these vessels can be demonstrated both by CT and by cardiac magnetic resonance imaging, traditional magnetic resonance coronary angiography (MRCA) is a time consuming examination that requires multiple, double oblique, three-dimensional (3D) acquisitions that are targeted to the likely course of the coronary. A recently introduced technique allows visualisation of all three coronary arteries with a single 3D volume acquisition. This ‘‘whole heart coronary imaging’’ (WHCA) uses a navigator-gated sequence to generate a 3D volume stack, which can subsequently be analysed as axial slices or reformatted to produce multi-planer, or volume rendered images.

Aims: To evaluate the utility of WHCA to define the proximal course of anomalous coronary arteries.

Methods: Between April 2006 and November 2006 seven patients who were referred for cardiac MRI because of known or suspected anomalous coronaries were evaluated by both traditional targeted acquisitions which were either navigated free breathing or breath hold, and with WHCA. WHCA was performed with a sufficient number of transverse slices to cover the proximal course of the anomalous coronary using an SSFP sequence with a fat suppression and T2 preparation prepulses TR/TE/flip angle 4.6/ 2.3/100 and spatial resolution was 1.1861.1861.80 mm. Both sets of images were then assessed independently for visual quality of the coronary images and diagnostic ability. The sequence which most clearly and unequivocally defined the course of the vessel was judged superior.

Results: Thirty four sequences were used in the 7 patients, of which 24 were targeted. Ten of these targeted acquisitions provided unambiguous diagnostic images, but in 3 patients the multiple targeted sequences were unable to adequately demonstrate the course of the anomalous vessel. Nine WHCA sequences were performed, of which only one did not provide diagnostic images. Image quality was assessed as superior for the targeted sequences in 2 patients, for the WHCA in 3 patients and equivalent in 2 patients.

Conclusions: Magnetic resonance WHCA is feasible in patients with anomalous coronary arteries. It provides diagnostic quality images in the majority of cases. As it does not require complex planning, WHCA may be preferable as the initial sequence to demonstrate anomalous vessels.