No abstract

Cardiac magnetic resonance imaging (CMR) with adenosine-stress myocardial perfusion is gaining importance for the detection and quantification of coronary artery disease (CAD). However, there is little knowledge about patients with CMR-detected ischemia, but having no relevant stenosis as seen on coronary angiography (CA). The aims of our study were to characterize these patients by CMR and CA and evaluate correlations and potential reasons for the ischemic findings. 73 patients with an indication for CA were first scanned on a 1.5T whole-body CMR-scanner including adenosine-stress first-pass perfusion. The images were analyzed by two independent investigators for myocardial perfusion which was classified as subendocardial ischemia (n = 22), no perfusion deficit (n = 27, control 1), or more than subendocardial ischemia (n = 24, control 2). All patients underwent CA, and a highly significant correlation between the classification of CMR perfusion deficit and the degree of coronary luminal narrowing was found. For quantification of coronary blood flow, corrected Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) was evaluated for the left anterior descending (LAD), circumflex (LCX) and right coronary artery (RCA). The main result was that corrected TFC in all coronaries was significantly increased in study patients compared to both control 1 and to control 2 patients. Study patients had hypertension or diabetes more often than control 1 patients. In conclusion, patients with CMR detected subendocardial ischemia have prolonged coronary blood flow. In connection with normal resting flow values in CAD, this supports the hypothesis of underlying coronary microvascular impairment. CMR stress perfusion differentiates non-invasively between this entity and relevant CAD.

In a great number of patients being referred to cath lab with ACC/AHA class II indication for CXA, CMR provides a high accuracy for decision making regarding appropriateness of the invasive exam. CMR prior to CXA could substantially reduce pure diagnostic coronary angiographies in patients with intermediate probability for CAD, in our patient-cohort from approximately 34% to 6%. Further studies are warranted to identify rare false negative CMR results.

No abstract

Purpose: To prospectively determine the negative predictive value of normal adenosine stress cardiac MR (CMR) in routine patients referred for evaluation of coronary artery disease (CAD), predominantly with intermediate to high pretest risk. Materials and Methods:Consecutive patients referred for coronary angiography were examined in a 1.5 Tesla whole-body scanner before catheterization. A total of 158 patients with normal CMR on qualitative assessment were included, and semiquantitative perfusion analysis was performed. Significant CAD was regarded as luminal narrowing of !70% in coronary angiography.Results: In the 158 study patients, negative predictive value of normal adenosine-stress CMR for significant CAD was 96.2% (for stenosis !90%: 98.1%). True-negative and false-negative patients were comparable regarding clinical presentation, risk factors, and CMR findings. Semiquantitative perfusion analysis gave significantly prolonged arrival time index and peak time index in the false-negative group. Using cutoff values >1.8 for arrival time index or >1.2 for peak time index, the CMR negative predictive value increased to 98.7% (for stenosis !90%: to 100%). Conclusion:The very high negative predictive value for CAD supports CMR-based decision making for the indication to coronary angiography. Semiquantitative perfusion analysis seems promising to identify the small group of CAD patients not detectable by qualitative CMR assessment.