Motion-compensated T₁ mapping in cardiovascular magnetic resonance imaging: a technical review

$$ mapping is becoming a staple magnetic resonance imaging method for diagnosing myocardial diseases such as ischemic cardiomyopathy, hypertrophic cardiomyopathy, myocarditis, and more. Clinically, most $$ mapping sequences acquire a single slice at a single cardiac phase across a 10 to 15-heartbeat breath-hold, with one to three slices acquired in total. This leaves opportunities for improving patient comfort and information density by acquiring data across multiple cardiac phases in free-running acquisitions and across multiple respiratory phases in free-breathing acquisitions. Scanning in the presence of cardiac and respiratory motion requires more complex motion characterization and compensation. Most clinical mapping sequences use 2D single-slice acquisitions; however newer techniques allow for motion-compensated reconstructions in three dimensions and beyond. To further address confounding factors and improve measurement accuracy, $$ maps can be acquired jointly with other quantitative parameters such as $$, $$, fat fraction, and more. These multiparametric acquisitions allow for constrained reconstruction approaches that isolate contributions to $$ from other motion and relaxation mechanisms. In this review, we examine the state of the literature in motion-corrected and motion-resolved $$ mapping, with potential future directions for further technical development and clinical translation.