Validation of an ultrahigh contrast divided subtracted inversion recovery technique using a standard T₁ phantom

The divided subtracted inversion recovery (dSIR) is a high T 1 contrast technique that shows changes in white matter in patients with traumatic brain injury and hypoxic injury. The changes can be explained by small differences in T 1 ; however, to date, there has been no independent validation of the technique using a standard reference. The present study develops the theory of the dSIR signal and performs validation using the NIST/ISMRM T 1 phantom. Non‐idealities are explored, including the influence of noise bias and finite repetition time (TR), which leads to the introduction of an optimally efficient TR for inversion recovery acquisitions. Results show excellent agreement with theoretical calculations.