Recurrent coronary artery stenosis: assessment with three-dimensional MR imaging

To assess the diagnostic value of three-dimensional coronary magnetic resonance (MR) angiography with fat saturation and navigator echo in the setting of restenosis after percutaneous transluminal coronary angioplasty (PTCA).

Thirty consecutive patients who had PTCA and were referred for elective coronary reangiography underwent MR imaging and coronary angiography. The pulse sequence was a cardiac triggered, single-slab, three-dimensional, gradient-echo sequence, employing a spin-echo navigator echo measurement to track the variation of the diaphragm during the scan. The following segments of the coronary arteries were included in this prospective study: left main coronary artery, proximal and middle left anterior descending, proximal and middle left circumflex, proximal and middle right coronary artery, and intermediate branch, if present. The quality of the MR images was graded from 0 to 5.

In total, 221 coronary artery segments could be identified. Mean image quality was 3.3. Overall accuracy for segments with an image quality of grade 2 or more was 90%. To achieve a positive predictive value >70% for a significant stenosis/restenosis, only segments with quality >/=3 could be assessed, whereas an acceptable negative predictive value could be achieved for nearly all segments.

Our preliminary data suggest that MR coronary angiography may be most helpful as a screening test in selected patients to exclude clinically relevant stenoses or to assess restenoses after PTCA or in patients in whose coronary angiography is relatively contraindicated.