6 × 0.6 × 1.25 mm) have been demonstrated. McGann et al. combined this technique with

3-D visualization and quantification to assess left atrial scarring before and following atrial fibrillation ablation. They found that subjects with more than 13% left atrial delayed enhancement following ablation had a nearly 20 times higher chance of being free from atrial fibrillation than those with low amounts of post-ablation delayed enhancement.57 The technique Inhibitors,research,lifescience,medical is now being used to image immediately following the procedure to target further ablation and potentially reduce the need for repeat procedures. Interestingly, high-resolution 3-D DECMR may also be useful for better identifying patients who will respond poorly to current ablation Inhibitors,research,lifescience,medical techniques.58 Of note, such high-resolution imaging is not yet feasible

in all patients. In the above studies, imaging took 5 to 10 minutes, and 10% to 30% of patients were excluded from analysis because of poor image quality that was attributed to patient motion, significant arrhythmia, or incorrect inversion time selection. Techniques to improve the speed and reliability of high-resolution CMR require further investigation. FASTER MR IMAGING While cardiac gating can be used to generate MR images with excellent spatial resolution by splitting data collection over Inhibitors,research,lifescience,medical multiple heart-beats, real-time CMR requires a more deliberate trade-off between temporal and spatial resolution. To visualize catheters adequately, MRI-guided EP procedures require Inhibitors,research,lifescience,medical an in-plane spatial resolution of around 2 mm2. The target temporal resolution is 7 frames per second (fps), the usual X-ray fluoroscopy frame rate

for clinical EP procedures. Since the initial 1 fps imaging used to guide the first MR-guided EP procedure38 faster, stronger gradients have increased the temporal resolution capabilities of fast gradient-recalled echo sequences to the 5 fps range.59 Improved gradient exactly performance and B0 field homogeneity have also allowed real-time imaging to be performed with Inhibitors,research,lifescience,medical coherent steady state pulse sequences (i.e. steady-state free precession, true fast imaging Cilengitide with steady-state precession (true-FISP), or Fast Imaging Employing Steady-state Acquisition). These sequences provide increased contrast-to-noise performance at a given frame rate compared with fast gradient-recalled echo sequences.59 Parallel imaging techniques can provide additional improvement in temporal resolution without sacrificing spatial resolution. These techniques accelerate imaging by covering the region of interest with multiple receive coils and using the different spatial sensitivities of these coils to correct for undersampling of image data.60 The acceleration achieved from acquiring less data is countered by the increased processing time required for estimating coil sensitivities and for performing the parallel reconstruction.