Assessment of coronary artery bypass grafts patency with different magnetic resonance technologies

The aim of the study was to evaluate the diagnostic accuracy of different magnetic resonance (MR) sequences in the assessment of coronary artery bypass graft patency and the evaluation of distal anastomoses with a spin echo sequence (Haste).

Twenty-five patients were examined with all the three techniques and 185 patients with 481 distal anastomoses were examined with the Haste sequence at a 1.5 TMR scanner and coronary angiography. A two-dimensional T(2)-weigthed breath-hold half-Fourier acquisition single-shot turbo spin echo sequence (Haste), a Navigator sequence and a gadolinium-enhanced Fisp-3-D sequence were performed. All images were evaluated independently by a radiologist and cardiologist and compared to the conventional coronary angiography. The observers were blinded to the coronary angiography findings, but informed in regard to the surgical graft anastomosis.

With the Haste sequence 80% of the distal anastomoses were recognized. The sensitivity and specificity for the evaluation of the distal anastomosis with the Haste sequence was 94% and 75%. The Navigator and the Fisp-3-D sequences showed a sensitivity of 74% and 94% and a specificity of 78% and 88%.

The best results were achieved with the Haste sequence, a reliable assessment of graft patency of the distal anastomosis is possible. The best imaging of proximal IMA segments was possible with the Fisp-3-D sequence. Due to the low sensitivity and specificity, the use of the Navigator sequence was stopped in our center. Further improvements of the spatial resolution and the image quality are necessary to recommend this MR techniques for routine clinical use.