Abstract 2240: T2-Prepared Steady-State Free-Precession Blood Oxygenation Level-Dependent MRI in Patients with Coronary Artery Disease and Normal Volunteers: Validation against PET
Blood oxygenation level-dependent (BOLD) MRI clinical studies at 1.5 Tesla (T) have been principally limited by low signal to noise. We sought to apply this method at 3T in patients with coronary artery disease (CAD) and normal volunteers, and validated it against perfusion measurements by PET. Twenty-two patients (age 62±8 yrs, 16 men) with CAD (at least 1 stenosis > 50% on quantitative coronary angiography-QCA) and 10 normal volunteers (age 52±7 yrs, 7 men) underwent 3T BOLD MRI and PET. For BOLD MRI a mid-ventricular slice was acquired every 30sec at rest and during adenosine stress (140 μg/kg/min). A set of 6 images was acquired at rest and at peak stress. Using PET with oxygen-15 labelled water, myocardial blood flow (MBF) was measured at baseline and during adenosine hyperemia. The BOLD short-axis view was divided into 6 segments, according to the mid-ventricular segments of the 17-AHA segment model, and mean signal intensities (SI) were calculated using QMass (Medis) software. PET images were analyzed with MATLAB software (MathWorks Inc.) and registered with the BOLD short-axis image using anatomical landmarks. Taking QCA as the gold standard, cut-off values for stress MBF (< 2.57ml/min/g - AUC 0.79) and BOLD SI change (< 4.75% -AUC 0.78) were determined to define ischemic segments. Rest MBF, stress MBF, coronary flow reserve and BOLD-SI change of ischemic (n=69), remote to ischemia (n=73) and normal segments (n=60) are shown in table⇓. BOLD MRI and PET agreed on the presence or absence of ischemia in 18 of the 22 patients (82%), and in all normals. With regards to per segment analysis: taking PET as the gold standard and by applying the cut-off values for stress MBF and BOLD SI, BOLD MRI had only moderate sensitivity (61%) but good specificity (88%) for the identification of ischemia. T2-prepared SSFP 3T BOLD imaging is feasible in the clinical setting and has good agreement with PET perfusion measurements for the detection of myocardial ischemia.