The Measurement of Absolute Myocardial Perfusion in Patients with Coronary Artery Disease using 3T CMR and 1.5T CMR: Validation against PET

Abstract

Objectives: To validate absolute measurement of myocardial blood flow (MBF) with 1.5 Tesla (T) and 3T cardiovascular magnetic resonance (CMR) using positron emission tomography (PET) as the gold standard. Methods: 21 healthy subjects and 44 patients with coronary artery disease (CAD) were randomised to undergo PET scanning using oxygen 15-labeled water and CMR scanning at either 1.5T or 3T, using a saturation recovery fast-gradient echo sequence and 0.04 mmol/kg gadolinium bolus. MBF was assessed at rest and during adenosine stress. CMR MBF was determined by model independent deconvolution Results: There was no significant difference in rest and stress rate pressure product during PET and CMR scanning at either field strength. Agreement between the two methods was tested by Bland Altman plots The mean difference between PET MBF and 3T CMR MBF was 0.30 ml/g/min, limits of agreement of -1.23 and 1.89 ml/g/min. For the 3T cohort the sensitivity and specificity for the detection of coronary stenoses ≥50 % was 87% and 81 % for PET (threshold 1.93 ml/g/min) and 61% and 78% (threshold 1.73 ml/g/min) for 3T CMR. The mean difference between PET and 1.5T CMR was 0.05 ml/g/min, limits of agreement of -1.75 and 1.84 ml/g/min. For the 1.5T cohort the sensitivity and specificity for the detection of coronary stenoses ≥50 % was 84% and 94% for PET (threshold 1.98 ml/g/min) and 81% and 78% (threshold 2.29ml/g/min) for CMR. Conclusion: This study demonstrates there is no significant difference in mean MBF as measured by PET and CMR at either 1.5T or 3T CMR. However there is marked variation in values of MBF between different segments as demonstrated by the wide limits of agreements.