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Off‐resonance saturation ratio obtained with ultrashort echo time‐magnetization transfer techniques is sensitive to changes in static tensile loading of tendons and degeneration
Author(s) -
Chang Eric Y.,
Du Jiang,
Biswas Reni,
Statum Sheronda,
Pauli Chantal,
Bae Won C.,
Chung Christine B.
Publication year - 2015
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.24881
Subject(s) - offset (computer science) , materials science , magnetization transfer , ultimate tensile strength , confidence interval , tendon , anatomy , nuclear magnetic resonance , nuclear medicine , biomedical engineering , physics , magnetic resonance imaging , medicine , radiology , composite material , computer science , programming language
Background To determine if off‐saturation ratio (OSR) measured with the ultrashort echo time magnetization transfer (UTE‐MT) sequence could differentiate between tendons under different states of tensile load and to compare these changes between normal versus degenerated tendons. Methods Fourteen tendons were imaged at 3 Tesla before and during the application of 0.5–1 kg tension. A two‐dimensional (2D) ‐UTE‐MT sequence with 1.5, 3, and 5 kHz frequency offsets was used on nine tendons and a 3D‐UTE‐MT sequence with 1.5 kHz frequency offset was used on five tendons. OSR was calculated and compared for each condition. Histologic correlation was performed using light microscopy. Results In general, OSR increased after the application of tension. Mean increase of 2D OSR was 0.035 (95% confidence interval [CI], 0.013–0.056) at 1.5 kHz offset ( P < 0.01), 0.031 (95% CI, 0.023–0.040) at 3 kHz offset ( P < 0.01), and 0.013 (95% CI, −0.013–0.027) at 5 kHz offset ( P = 0.07) from pre‐ to posttension states. Mean increase of 3D OSR was 0.026 (95% CI, 0.008–0.044) at a 1.5 kHz offset ( P = 0.02) from pre‐ to posttension states. Mean decrease of 2D OSR at 1.5 kHz offset was 0.074–0.087 when comparing normal versus degenerated tendons ( P < 0.01). Conclusion OSR as measured with 2D or 3D UTE‐MT sequences can detect the changes in hydration seen when tendons are placed under two different states of tensile load, but these changes are smaller than those encountered when comparing between normal versus pathologic tendons. Lower off‐resonance saturation frequencies (3 kHz or less) are more sensitive to these changes than higher off‐resonance saturation frequencies.J. Magn. Reson. Imaging 2015. J. Magn. Reson. Imaging 2015;42:1064–1071.