Search

Objectives The purpose of this study was to assess the diagnostic accuracy of blood oxygen-level dependent (BOLD) MRI in suspected coronary artery disease (CAD). Background By exploiting the paramagnetic properties of deoxyhemoglobin, BOLD magnetic resonance imaging can detect myocardial ischemia. We applied BOLD imaging and first-pass perfusion techniques to: 1) examine the pathophysiological relationship between coronary stenosis, perfusion, ventricular scar, and myocardial oxygenation; and 2) evaluate the diagnostic performance of BOLD imaging in the clinical setting. Methods BOLD and first-pass perfusion images were acquired at rest and stress (4 to 5 min intravenous adenosine, 140 mu g/kg/min) and assessed quantitatively (using a BOLD signal intensity index [stress/resting signal intensity], and absolute quantification of perfusion by model-independent deconvolution). A BOLD signal intensity index threshold to identify ischemic myocardium was first determined in a derivation arm (25 CAD patients and 20 healthy volunteers). To determine diagnostic performance, this was then applied in a separate group comprising 60 patients with suspected CAD referred for diagnostic angiography. Results Prospective evaluation of BOLD imaging yielded an accuracy of 84%, a sensitivity of 92%, and a specificity of 72% for detecting myocardial ischemia and 86%, 92%, and 72%, respectively, for identifying significant coronary stenosis. Segment-based analysis revealed evidence of dissociation between oxygenation and perfusion (r = -0.26), with a weaker correlation of quantitative coronary angiography with myocardial oxygenation (r = -0.20) than with perfusion (r = -0.40; p = 0.005 for difference). Hypertension increased the odds of an abnormal BOLD response, but diabetes mellitus, hypercholesterolemia, and the presence of ventricular scar were not associated with significant deoxygenation. Conclusions BOLD imaging provides valuable insights into the pathophysiology of CAD; myocardial hypoperfusion is not necessarily commensurate with deoxygenation. In the clinical setting, BOLD imaging achieves favorable accuracy for identifying the anatomic and functional significance of CAD. (J Am Coll Cardiol 2012; 59: 1954-64) (C) 2012 by the American College of Cardiology Foundation

Background— It is recognized that the interplay between myocardial ischemia, perfusion, and oxygenation in the setting of coronary artery disease (CAD) is complex and that myocardial oxygenation and perfusion may become dissociated. Blood oxygen level–dependent (BOLD) cardiovascular magnetic resonance (CMR) has the potential to noninvasively measure myocardial oxygenation, whereas positron emission tomography (PET) with oxygen-15 labeled water is the gold standard technique for myocardial blood flow quantification. Thus, we sought to apply BOLD CMR at 3 T and oxygen-15–labeled water PET in patients with CAD and normal volunteers to better understand the relationship between regional myocardial oxygenation and blood flow during vasodilator stress. Methods and Results— Twenty-two patients (age, 62�8 years; 16 men) with CAD (at least 1 stenosis ≥50% on quantitative coronary angiography) and 10 normal volunteers (age, 58�6 years; 6 men) underwent 3-T BOLD CMR and PET. For BOLD CMR, 4 to 6 midventricular short-axis images were acquired at rest and during adenosine stress (140 μg/kg/min). Using PET with oxygen-15–labeled water, myocardial blood flow was measured at baseline and during adenosine in the same slices. BOLD images were divided into 6 segments, and mean signal intensities calculated. Taking ≥50% stenosis on quantitative coronary angiography as the gold standard, cutoff values for stress myocardial blood flow ( Conclusions— Regional myocardial perfusion and oxygenation may be dissociated, indicating that in patients with CAD, reduced perfusion does not always lead to deoxygenation.