Depiction of achilles tendon microstructure in vivo using high-resolution 3-dimensional ultrashort echo-time magnetic resonance imaging at 7 T.
OBJECTIVE
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Misung
M
Han
Peder E Z
PE
Larson
Jing
J
Liu
Roland
R
Krug
D000125:Achilles Tendon / Q000033:anatomy & histology*; D000328:Adult; D016477:Artifacts; D005240:Feasibility Studies; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012680:Sensitivity and Specificity