Abstract 332: High Spatial Resolution 3T Stress Myocardial Perfusion MRI Using K-t Sense and B1-insensitive Saturation
PURPOSE: The improved SNR at 3T can contribute to achieve myocardial perfusion MRI with high spatial resolution and high temporal resolution. However, 3T myocardial perfusion MRI has been limited by inaccurate saturation due to increased B1 inhomogeneities. The purpose of this study was to evaluate the diagnostic accuracy of high spatial and temporal resolution stress perfusion MRI at 3T, by using B1-insensitive saturation pulses and k-t SENSE.
METHOD AND MATERIALS: High spatial resolution (<2mm) perfusion MR images were obtained in 126 patients with suspected coronary artery disease (CAD) during pharmacologic stress and at rest. Three short-axis slices of the left ventricle were imaged every heartbeat using a Turbo field-echo sequence with B1-insensitive saturation (TR/TE/FA=3.7ms/1.9ms/20degrees, FOV=410mm, matrix=288×187, thickness=8mm, k-t factor=8). Image quality score (1:poor - 4:excellent) and presence or absence of myocardial ischemia were determined using a 16-segment model by consensus of two observers. Diagnostic performance of stress perfusion MRI was evaluated in 59 patients who underwent X-ray coronary angiography within 2 weeks from MRI.
RESULTS: Perfusion MR images were successfully acquired in all patients, with the average image quality score of 3.9±0.3. With B1 insensitive saturation pulses, homogenous saturation was achieved in the entire imaging field, and signal intensity on perfusion MRI was found to be arrhythmia insensitive. For the prediction of significant narrowing (>70%) on coronary angiography, the area under ROC curve of stress perfusion MRI was 0.94 (95% CI; 0.86–1.00) on a patient-based analysis and 0.90 (0.84–0.96) on a vessel-based analysis. The patient-based sensitivity, specificity, positive and negative predictive values of stress perfusion MRI were 88%(29/33), 96%(25/26), 97%(29/30), and 86%(25/29), respectively.
CONCLUSION: Three short-axis slices of high spatial resolution perfusion MRI can be obtained every heartbeat using 3T MR imager and k-t SENSE. Arrhythmia insensitive, uniform saturation can be achieved with B1 insensitive pulses. 3T stress perfusion MRI using k-t SENSE and B1-insensitive saturation can provide an accurate detection of myocardial ischemia in patients with CAD.