title: Ultrashort TE T1ρ magic angle imaging.
abstract: An ultrashort TE T(1)ρ sequence was used to measure T(1) ρ of the goat posterior cruciate ligament (n = 1) and human Achilles tendon specimens (n = 6) at a series of angles relative to the B(0) field and spin-lock field strengths to investigate the contribution of dipole-dipole interaction to T(1)ρ relaxation. Preliminary results showed a significant magic angle effect. T(1)ρ of the posterior cruciate ligament increased from 6.9 ± 1.3 ms at 0° to 36 ± 5 ms at 55° and then gradually reduced to 12 ± 3 ms at 90°. Mean T(1)ρ of the Achilles tendon increased from 5.5 ± 2.2 ms at 0° to 40 ± 5 ms at 55°. T(1)ρ dispersion study showed a significant T(1)ρ increase from 2.3 ± 0.9 ms to 11 ± 3 ms at 0° as the spin-lock field strength increased from 150 Hz to 1 kHz, and from 30 ± 3 ms to 42 ± 4 ms at 55° as the spin-lock field strength increased from 100 to 500 Hz. These results suggest that dipolar interaction is the dominant T(1)ρ relaxation mechanism in tendons and ligaments.
authors.affiliation: Department of Radiology, University of California, San Diego, California 92103-8756, USA. jiangdu@ucsd.edu
authors.forename: Jiang
authors.initials: J
authors.lastname: Du
authors.forename: Sheronda
authors.initials: S
authors.lastname: Statum
authors.forename: Richard
authors.initials: R
authors.lastname: Znamirowski
authors.forename: Graeme M
authors.initials: GM
authors.lastname: Bydder
authors.forename: Christine B
authors.initials: CB
authors.lastname: Chung
mesh_terms: D000125:Achilles Tendon / Q000033:anatomy & histology*; D000465:Algorithms; D000818:Animals; D016118:Anterior Cruciate Ligament / Q000033:anatomy & histology*; D006041:Goats; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity