Comparison of Two MRI-UTE Sequences for the Quantification (T1) of the Human Achilles Tendon

INTRODUCTION: The Achilles tendon is commonly involved in both degenerative and inflammatory tendinopathies. The short T2 of the normal tendon makes early changes difficult to assess with conventional MR sequences. Ultrashort echo time imaging (UTE) [1] can directly visualize the tendon signal allowing quantification, such as T1 relaxometry. T1 measurements may be useful for assessing Achilles disease directly or for other techniques such as pharmacokinetic modelling of contrast enhancement. The aim of this work was to compare the T1 measurements in human Achilles tendon obtained from a saturation recovery (SR-) UTE and variable flip angle (VFA-) UTE sequence where these sequences were initially corroborated in long T2 phantoms with an assumed ‘gold standard’ inversion recovery spin echo (IR-SE) sequence.