In vivo evaluation of human patellar tendon microstructure and microcirculation with diffusion MRI

Kenneth Wengler, Takeshi Fukuda, Dharmesh Tank, David E. Komatsu, Megan Paulus, Mingqian Huang, Elaine S. Gould, Mark E. Schweitzer, Xiang He

Research output: Contribution to journalArticle

Abstract

Background: Patellar tendon (PT) microstructure integrity and microcirculation status play a crucial role in the progression of tendinopathy and tendon repair. Purpose: To assess the feasibility and robustness of stimulated-echo based diffusion-weighted MRI with readout-segmented echo-planar imaging (ste-RS-EPI) for noninvasive assessment of microstructure and microcirculation of human PT. Study Type: Prospective. Subjects: Fifteen healthy volunteers. Field Strength/Sequence: PT diffusion tensor imaging (DTI) and intravoxel incoherent motion (IVIM) were acquired with an ste-RS-EPI protocol on a 3T MRI scanner. Assessment: Subjects were positioned with their PT at the magic angle. DTI-derived parameters including axial diffusivity (AD), radial diffusivity (RD), mean diffusivity (MD), and fractional anisotropy (FA) were estimated with b-values of 0 and 800 s/mm2 and 12 diffusion directions. IVIM-derived parameters, fp, D* × fp, Vb, and D* × Vb were assessed in the central-third and the outer-two thirds of the PT with b-values of 0, 20, 30, 60, 80, 120, 200, 400, and 600 s/mm2 in three orthogonal directions. Statistical Tests: Paired t-tests were used to evaluate differences in IVIM parameters between the central-third and outer-two thirds regions of the patellar tendon. Paired t-tests and within-subject coefficient of variation were used to assess the intra- and intersession reproducibility of PT DTI and IVIM parameters. Results: DTI parameters for healthy PT were 1.54 ± 0.09 × 10-3 mm2/s, 1.01 ± 0.05 × 10-3 mm2/s, 1.18 ± 0.06 × 10-3 mm2/s, and 0.30 ± 0.04 for AD, RD, MD, and FA, respectively. Significantly higher (P < 0.05) IVIM parameters fp and D* × fp were observed in the outer-two thirds (6.1% ± 2.4% and 95.2 ± 49.6, respectively) compared with the central-third (3.8% ± 2.3% and 48.6 ± 35.2, respectively) of the PT. Data Conclusion: Diffusion MRI of PT with an ste-RS-EPI protocol is clinically feasible. Both DTI- and IVIM-derived parameters of the PT demonstrated good test–retest reproducibility and interrater reliability. Level of Evidence: 2. Technical Efficacy: Stage 1. J. Magn. Reson. Imaging 2019.

Original languageEnglish (US)
JournalJournal of Magnetic Resonance Imaging
DOIs
Publication statusAccepted/In press - Jan 1 2019
Externally publishedYes

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Keywords

  • DTI
  • IVIM
  • microcirculation
  • microstructure
  • patellar tendon

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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