BMC Musculoskeletal Disorders (2019-09-01)

Abbreviated quantitative UTE imaging in anterior cruciate ligament reconstruction

  • Takeshi Fukuda,
  • Kenneth Wengler,
  • Dharmesh Tank,
  • Seth Korbin,
  • James M. Paci,
  • David E. Komatsu,
  • Megan Paulus,
  • Mingqian Huang,
  • Elaine Gould,
  • Mark E. Schweitzer,
  • Xiang He

Journal volume & issue
Vol. 20, no. 1
pp. 1 – 14


Read online

Abstract Background Existing ultrashort echo time magnetic resonance imaging (UTE MRI) methods require prohibitively long acquisition times (~ 20–40 min) to quantitatively assess the clinically relevant fast decay T2* component in ligaments and tendons. The purpose of this study was to evaluate the feasibility and clinical translatability of a novel abbreviated quantitative UTE MRI paradigm for monitoring graft remodeling after anterior cruciate ligament (ACL) reconstruction. Methods Eight patients who had Graftlink™ hamstring autograft reconstruction were recruited for this prospective study. A 3D double-echo UTE sequence at 3.0 Tesla was performed at 3- and 6-months post-surgery. An abbreviated UTE MRI paradigm was established based on numerical simulations and in vivo validation from healthy knees. This proposed approach was used to assess the T2* for fast decay component ( T2s∗ $$ {T}_{2s}^{\ast } $$) and bound water signal fraction (f bw ) of ACL graft in regions of interest drawn by a radiologist. Results Compared to the conventional bi-exponential model, the abbreviated UTE MRI paradigm achieved low relative estimation bias for T2s∗ $$ {T}_{2s}^{\ast } $$ and f bw over a range of clinically relevant values for ACL grafts. A decrease in T2s∗ $$ {T}_{2s}^{\ast } $$ of the intra-articular graft was observed in 7 of the 8 ACL reconstruction patients from 3- to 6-months (− 0.11 ± 0.16 ms, P = 0.10). Increases in T2s∗ $$ {T}_{2s}^{\ast } $$ and f bw from 3- to 6-months were observed in the tibial intra-bone graft ( ΔT2s∗ $$ {\varDelta T}_{2s}^{\ast } $$: 0.19 ± 0.18 ms, P < 0.05; Δf bw : 4% ± 4%, P < 0.05). Lower T2s∗ $$ {T}_{2s}^{\ast } $$ (− 0.09 ± 0.11 ms, P < 0.05) was observed at 3-months when comparing the intra-bone graft to the graft/bone interface in the femoral tunnel. The same comparisons at the 6-months also yielded relatively lower T2s∗ $$ {T}_{2s}^{\ast } $$ (− 0.09 ± 0.12 ms, P < 0.05). Conclusion The proposed abbreviated 3D UTE MRI paradigm is capable of assessing the ACL graft remodeling process in a clinically translatable acquisition time. Longitudinal changes in T2s∗ $$ {T}_{2s}^{\ast } $$ and f bw of the ACL graft were observed.