Free‐breathing, non‐ECG, continuous myocardial T₁ mapping with cardiovascular magnetic resonance multitasking

Abstract

Purpose To evaluate the accuracy and repeatability of a free‐breathing, non‐electrocardiogram (ECG), continuous myocardial T 1 and extracellular volume (ECV) mapping technique adapted from the Multitasking framework. Methods The Multitasking framework is adapted to quantify both myocardial native T 1 and ECV with a free‐breathing, non‐ECG, continuous acquisition T 1 mapping method. We acquire interleaved high–spatial resolution image data and high–temporal resolution auxiliary data following inversion‐recovery pulses at set intervals and perform low‐rank tensor imaging to reconstruct images at 344 inversion times, 20 cardiac phases, and 6 respiratory phases. The accuracy and repeatability of Multitasking T 1 mapping in generating native T 1 and ECV maps are compared with conventional techniques in a phantom, a simulation, 12 healthy subjects, and 10 acute myocardial infarction patients. Results In phantoms, Multitasking T 1 mapping correlated strongly with the gold‐standard spin‐echo inversion recovery (R 2 = 0.99). A simulation study demonstrated that Multitasking T 1 mapping has similar myocardial sharpness to the fully sampled ground truth. In vivo native T 1 and ECV values from Multitasking T 1 mapping agree well with conventional MOLLI values and show good repeatability for native T 1 and ECV mapping for 60 seconds, 30 seconds, or 15 seconds of data. Multitasking native T 1 and ECV in myocardial infarction patients correlate positively with values from MOLLI. Conclusion Multitasking T 1 mapping can quantify native T 1 and ECV in the myocardium with free‐breathing, non‐ECG, continuous scans with good image quality and good repeatability in vivo in healthy subjects, and correlation with MOLLI T 1 and ECV in acute myocardial infarction patients.