Rotator cuff tendon assessment using magic-angle insensitive 3D ultrashort echo time cones magnetization transfer (UTE-Cones-MT) imaging and modeling with histological correlation

J Magn Reson Imaging. 2018 Jul;48(1):160-168. doi: 10.1002/jmri.25914. Epub 2017 Dec 8.

Abstract

Background: Rotator cuff tendons (RCTs) are challenging to image due to the "magic angle effect" and their short T2 .

Purpose: To assess the degree of magic angle sensitivity of human RCTs and to utilize a 3D ultrashort echo time Cones sequence with magnetization transfer preparation (UTE-Cones-MT) and two-pool quantitative MT modeling with histological correlation. We hypothesized that MT parameters would be less sensitive to the magic angle compared with conventional T2 measurements.

Study type: Prospective imaging pathologic correlation.

Specimen: Twenty cadaveric rotator cuff tendons were imaged at five sample orientations ranging from 0-90° relative to the B0 field.

Field strength/sequence: 3T/3D UTE-Cones-MT and Carr-Purcell-Meiboom-Gill (CPMG).

Assessment: Two-pool quantitative MT modeling parameters and T2 values were calculated in regions of interest drawn by a medical physicist. Histopathological analysis was performed and mild and severe tendinopathy groups were assigned by a histopathologist and histotechnician.

Statistical tests: Coefficients of variations (CVs) were calculated for measures between the different orientations and group means were compared for each measure.

Results: CVs of T2 and macromolecular fractions between orientations were 26.14 ± 16.82% and 6.18 ± 2.77% (mean ± SD), respectively. T2 measurements at 0°, 27°, 70°, and 90° showed significant differences between the two histological groups (P = 0.004, 0.008, 0.003, and 0.015, respectively), but not at 55° (P = 0.611). Mean T2 value ranges between orientations for the mild and severe tendinopathy groups were 15.27-30.32 msec and 20.81-35.85 msec, respectively, showing overlap despite statistically significant differences (P = 0.003). Macromolecular fractions at all angles showed significant differences between the two groups (P < 0.0001). Mean fraction ranges between orientations for the mild and severe tendinopathy groups were 14.32-17.17% and 10.00-13.75% respectively (P < 0.0001) with no overlap.

Data conclusion: Compared with T2 , macromolecular fraction obtained with the 3D UTE-Cones-MT technique is resistant to the magic angle effect and is more sensitive to RCT degeneration.

Level of evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017.

Keywords: T2; macromolecular fraction; magnetization transfer; rotator cuff tendon; ultrashort TE.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Cadaver
  • Computer Simulation
  • Female
  • Humans
  • Image Interpretation, Computer-Assisted / methods
  • Image Processing, Computer-Assisted
  • Imaging, Three-Dimensional / methods*
  • Magnetic Resonance Imaging
  • Magnetics
  • Male
  • Middle Aged
  • Observer Variation
  • Prospective Studies
  • Reproducibility of Results
  • Rotator Cuff / diagnostic imaging*
  • Tendinopathy / diagnostic imaging*
  • Tendons / diagnostic imaging