Cardiac Magnetic Resonance T1-rho Mapping at 1.5TAurélien Bustin, PhD; et al. 
(IHU LIRYC, Heart Rhythm Disease Institute, Bordeaux, France)

Magnetic resonance myocardial T1ρ mapping holds significant promise for the quantitative characterization of myocardial injuries. 
At Bordeaux University Hospital, we have successfully applied myocardial T1ρ mapping in over 200 studies, encompassing both ischemic and non-ischemic cardiomyopathies across acute and chronic stages. 
In the article we share tips and tricks for successful T1ρ imaging and quantitative analysis.

Here are some key protocol recommendations that follow the clinical recommendations on parameter mapping from the Society for Cardiovascular Magnetic Resonance:

  1. T1ρ values should be measured in the absence of contrast agents.
  2. While in-plane motion correction is advisable if available, it is not a substitute for breath-holding.
  3. Ensure proper adjustment of the main magnetic field shim (focused on the heart) and the center frequency to minimize off-resonance effects.
  4. For a regular heart rhythm, we recommend collecting the images in mid-diastole.
  5. Regularly review the image quality during acquisition, monitor the heart rate and breath holding, inspect the source T1ρ-weighted images, and check for wrapping artifacts.
  6. T1ρ maps will be presented in color, with a color lookup table specifically for T1ρ mapping provided. We suggest using a site-specific value range to emphasize abnormal areas.
  7. Use any preferred on-site analysis software for region-of-interest drawing, left ventricular segmentation, and American Heart Association bullseye model generation. For quantitative analysis of maps, adhere to clinical recommendations for CMR mapping.
  8. T1ρ values may be affected by partial volume effects, the presence of thin muscle, and residual breathing motion. These factors may contribute to false positive diagnoses. In such instances, we recommend manually recalculating T1ρ values by measuring regions of interest from the non-motion-corrected source images.