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For pediatric patients with DMD, the contrast administration procedure associated with LGE testing may be challenging. Non-contrast CMR methods, such as T1 mapping, exist and are useful for early myocardial remodeling detection. It has been found that T1 levels are typically elevated in patients with DMD, compared to healthy individuals, even prior to LGE.[8]

The following SDTM examples show T1, T2, and extracellular volume test results. This example includes device information (i.e., device manufacturer, software, version information, specific settings for each subject); however, study requirements will determine what data should be included.

Add text on parametric mapping and DMD.

"Parametric mapping with CMR now permits the routine spatial visualization and quantification of changes in myocardial composition based on changes in T1, T2, and T2*(star) relaxation times and extracellular volume (ECV)." (Ref: https://jcmr-online.biomedcentral.com/articles/10.1186/s12968-017-0389-8)

The Native T1 mapping or longitudinal (T1) relaxation time is the time constant which determines the rate at which excited protons return to equilibrium. It is a measure of the time taken for spinning protons to realign with the external magnetic field. The T2 mapping or transverse (T2) relaxation time constant determines the rate at which excited protons reach equilibrium or go out of phase with each other. It is a measure of the time taken for spinning protons to lose phase coherence among the nuclei spinning perpendicular to the main field. The term "native" means contrast naive in this context. The T2 measurement is only done prior to contrast.

"T1 mapping stands for registering the course of recovery of longitudinal magnetism", this means the relaxation time after either the preparation step (saturation or inversion prepulse) followed by the acquisition of images at several time points during the T1 recover/relaxation. The T1 value represents the time when recovery of magnetism has reached a percentage of its original state (63%). The recovery rate relates to the myocardial tissue properties that may be altered by pathological tissue presence (ref: https://www.ahajournals.org/doi/10.1161/circresaha.116.307974). T1 mapping values increase with disease and decrease post contrast.

The following example shows parametric mapping (T1, T2, and extracellular volume) results. For brevity, a limited sample of tests after contrast are shown in this example.