High-resolution spin-echo Cardiac Diffusion-Weighted MRI with motion compensated Convex Optimized Diffusion Encoding (CODE)
نویسندگان
چکیده
Background Cardiac Diffusion Weighted MRI (cDWI) has the potential to characterize myocardial infarction (MI) without contrast. However, the clinical utility of cDWI has been limited by severe sensitivity to cardiac motion that manifests as signal dropouts which corrupt measures of myocardial diffusivity. This can be managed by carefully timing the diffusion encoding gradients (GDiff) to a quiescent diastolic phase, but this approach is burdensome and highly sensitive to heart-rate changes. More recently, motion compensated (MOCO) diffusion encoding gradients with nulled first (M1) and second (M2) moments have demonstrated good robustness to cardiac motion (Stoeck, MRM 2015, Nguyen, MRM 2013) but they necessarily increase the echo time (TE) compared to monopolar encoding (MONO), which reduces SNR and/or limits spatial resolution. We have developed a MOCO cDWI sequence that employs Convex Optimized Diffusion Encoding (CODE) to reduce bulk motion sensitivity and shorten TE compared to existing MOCO schemes.
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