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High-dose dobutamine stress MRI allows for a reliable detection of significant in-stent stenoses.

High-dose dobutamine stress MRI allows for a reliable detection of significant in-stent stenoses, a team of researchers has found. The results of the study led by Dr. Thomas Schlosser from the University Hospital Essen, Germany, were presented on Friday during the European Congress of Radiology in Vienna, Austria.

The study investigated the value of high-dose dobutamine stress MR imaging in CAD patients after percutaneous coronary interventions (PCI) for the detection of restenoses using invasive coronary angiography as the standard of reference.

Fifty patients with known coronary artery disease who had undergone PCI with stent placement were examined with high-dose dobutamine stress MR imaging and invasive coronary angiography. MR imaging was performed on a 1.5 T MR scanner using a segmented steady state free precession sequence.

All examinations were evaluated by an experienced radiologist and a cardiologist in consensus. Myocardial ischemia was defined by new or worsening stress-induced wall motion abnormalities in more than one myocardial segment.

In the 50 patients, coronary stents were placed in 74 coronary arteries. Seven in-stent stenoses were found by use of invasive coronary angiography; six of these cases were correctly diagnosed by MRI, one in-stent stenosis was missed by MRI, which resulted in a sensitivity of 86 per cent. Sixty-seven coronary arteries with implanted stents showed no significant stenoses in invasive coronary angiography; however, in seven of these vessels the MRI examination was false positive, which resulted in a specificity of 89 per cent.

The positive predictive value was 46 per cent and the negative one, 98 per cent. Diagnostic accuracy was 89 per cent.

"Due to a high diagnostic accuracy, the technique appears to be helpful in the selection of patients who need to undergo control invasive coronary angiography", the authors said.