Accelerated and high-resolution cardiac T₂ mapping through peripheral k-space sharing

To develop high-spatial-resolution cardiac T₂ mapping that allows for a reduced acquisition time while maintaining its precision. We implemented and optimized a new golden-angle radial T₂ mapping technique named SKRATCH (Shared k-space Radial T₂ Characterization of the Heart) that shares k-space peripheries of T₂ -weighted images while preserving their contrasts.

Six SKRATCH variants (gradient-recalled echo and balanced SSFP, free-breathing and breath-held, with and without a saturation preparation) were implemented, and their precision was compared with a navigator-gated reference technique in phantoms and 22 healthy volunteers at 3 T. The optimal breath-held SKRATCH technique was applied in a small cohort of patients with subacute myocardial infarction.

The faster free-breathing SKRATCH technique reduced the acquisition time by 52.4%, while maintaining the precision and spatial resolution of the reference technique. Similarly, the most precise and robust breath-held SKRATCH technique demonstrated homogenous T₂ values that did not significantly differ from the navigator-gated reference (T₂  = 39.9 ± 3.4 ms versus 39.5 ± 3.4 ms, P > .20, respectively). All infarct patients demonstrated a large T₂ elevation in the ischemic regions of the myocardium.

The optimized SKRATCH technique enabled the accelerated acquisition of high-spatial-resolution T₂ maps, was validated in healthy adult volunteers, and was successfully applied to a small initial group of patients.