The objective of this study was to demonstrate the feasibility of depicting the internal structure of the Achilles tendon in vivo using high-resolution 3-dimensional ultrashort echo-time (UTE) magnetic resonance imaging at 7 T.
For our UTE imaging, a minimum-phase radiofrequency pulse and an anisotropic field-of-view 3-dimensional radial acquisition were used to minimize the echo time and scan time. A fat saturation pulse was applied every 8 spoke acquisitions to reduce blurring and chemical shift artifacts from fat and to improve the dynamic range of the tendon signal. Five healthy volunteers and 1 patient were scanned with an isotropic spatial resolution of up to 0.6 mm. Fat-suppressed UTE images were qualitatively evaluated and compared with non–fat-suppressed UTE images and longer echo-time images.
High-resolution UTE imaging was able to visualize the microstructure of the Achilles tendon. Fat suppression substantially improved the depiction of the internal structure. The UTE images revealed a fascicular pattern in the Achilles tendon and fibrocartilage at the tendon insertion. In a patient who had tendon elongation surgery after birth, there was a clear depiction of disrupted tendon structure.
High-resolution fat-suppressed 3-dimensional UTE imaging at 7 T allows for the evaluation of the Achilles tendon microstructure in vivo.
From the Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA.
Received for publication July 31, 2013; and accepted for publication, after revision, November 9, 2013.
Conflict of interest and sources of funding: Supported by NIH R01AR057336 from the National Institutes of Health and University of California, San Francisco Radiology Seed Grant.
The authors report no conflicts of interest.
Reprints: Misung Han, PhD, China Basin Landing, 185 Berry St, Suite 350, Box 0946, San Francisco, CA 94107. E-mail: email@example.com.