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Magic angle effect on adiabatic T 1ρ imaging of the Achilles tendon using 3D ultrashort echo time cones trajectory
Author(s) -
Wu Mei,
Ma Yajun,
Wan Lidi,
Jerban Saeed,
Jang Hyungseok,
Chang Eric Y.,
Du Jiang
Publication year - 2020
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.4322
Subject(s) - achilles tendon , physics , magic angle , nuclear magnetic resonance , optics , tendon , anatomy , medicine , nuclear magnetic resonance spectroscopy
The protons in collagen‐rich musculoskeletal (MSK) tissues such as the Achilles tendon are subject to strong dipolar interactions which are modulated by the term (3cos 2 θ‐1) where θ is the angle between the fiber orientation and the static magnetic field B 0 . The purpose of this study was to investigate the magic angle effect in three‐dimensional ultrashort echo time Cones Adiabatic T 1ρ (3D UTE Cones‐AdiabT 1ρ ) imaging of the Achilles tendon using a clinical 3 T scanner. The magic angle effect was investigated by Cones‐AdiabT 1ρ imaging of five cadaveric human Achilles tendon samples at five angular orientations ranging from 0° to 90° relative to the B 0 field. Conventional Cones continuous wave T 1ρ (Cones‐CW‐T 1ρ ) and Cones T 2 * (Cones‐T 2 *) sequences were also applied for comparison. On average, Cones‐AdiabT 1ρ increased 3.6‐fold from 13.6 ± 1.5 ms at 0° to 48.4 ± 5.4 ms at 55°, Cones‐CW‐T 1ρ increased 6.1‐fold from 7.0 ± 1.1 ms at 0° to 42.6 ± 5.2 ms at 55°, and Cones‐T2* increased 12.3‐fold from 2.9 ± 0.5 ms at 0° to 35.8 ± 6.4 ms at 55°. Although Cones‐AdiabT 1ρ is still subject to significant angular dependence, it shows a much‐reduced magic angle effect compared to Cones‐CW‐T 1ρ and Cones‐T 2 *, and may be used as a novel and potentially more effective approach for quantitative evaluation of the Achilles tendon and other MSK tissues.