Mri of the Achilles Tendon Enthesis with Ultrashort Te (ute) Pulse Sequences: Ct, Radiographic and Anatomic Correlation

Introduction: To date, the contribution from magnetic resonance (MR) imaging to the study of the normal Achilles tendon enthesis has been limited. The principal tissues found at the insertion site, including the fibrous connective tissue of the Achilles tendon itself, uncalcified and calcified fibrocartilage, periosteum and cortical bone all have short T2s and characteristically display little or no signal with conventional pulse sequences. As a result it is difficult or impossible to separately identify specific tissues at the enthesis. By using ultrashort echo time (UTE) pulse sequences with TEs 20-50 times shorter than those of conventional pulse sequences, signal can be detected from tissues with short T2s (1, 2) and, in a preliminary study, it was suggested that the tissues of the Achilles tendon enthesis could be identified, although no correlative anatomic studies were performed (3). In this study we have used UTE sequences to image the Achilles tendon enthesis in cadavers and correlated the appearances with computed tomography, soft tissue radiography, anatomic and histologic studies.