Myocardial Stress MR Perfusion Imaging is being increasingly used in the evaluation of Coronary Artery Disease (CAD).
It has proven itself as an accurate (1) tool in the diagnosis of CAD.
a standardized protocol for classification of MR perfusion defects is still lacking.
The purpose of this paper was to determine cut-off values for the amount of inducible ischemia and make a risk stratification tool validated with coronary angiography as the standard for revascularization...
Methods and Materials
464 consecutive ambulatory patient medical records were screened.
227 had no previous coronary artery disease (CAD) and underwent both coronary angiography and adenosine stress MR perfusion at 1.5-T.
The amount of inducible ischemia was calculated by dividing the total score of all 16 segments by 48 (3x16 segments) and multiplied by 100.
Coronary angiography was used for validation and stenoses were classified as mild (<50%),
or severe (>75%).
Patients with severe stenosis (n=187) had a mean percentage of inducible ischemia of 14.4±7.5%,
as compared to 9.4±7.5% in the moderate (n=20),
and 4.2±3.8% in the mild (n=20) group.
Based on these results risk categories were defined as Myocardial Ischemia RADiologic SCORE (MIRADS) 5 (>10% inducible ischemia; n=144),
MIRADS 4 (≥5-≤10% inducible ischemia; n=59),
and MIRADS 3 (<5% inducible ischemia; n=24).
The evaluation and quantification of inducible myocardial ischemia can be determined with the MIRADS method and the cutoff values presented provide an easy risk stratification tool for revascularization therapy.
This method can be used for MR protocol standardization,
ischaemic risk classification,
communication in medical therapy,
and indication guidance for further revascularization.
1 Schwitter J,
Wilke N et al (2012) Superior diagnostic performance of perfusion-cardiovascular magnetic resonance versus SPECT to detect coronary artery disease: The secondary endpoints of the multicenter multivendor MR-IMPACT II (Magnetic Resonance Imaging for Myocardial Perfusion Assessment in Coronary Artery Disease Trial).
J Cardiovasc Magn Reson 14:61 2 Greenwood JP,
Younger JF et al (2012) Cardiovascular magnetic resonance and single-photon emission computed...