Background: A recent report suggests that semi-quantitative two-dimensional Goutallier grade (2D-GG) correlates poorly with quantitative three-dimensional Dixon fat fraction (3D-Dixon-FF) on magnetic resonance imaging (MRI).
Purpose: To determine whether the finding of poor correlation of supraspinatus 3D-Dixon-FF with 2D-GG is reproducible, and to determine the strength of the correlation of 3D-Dixon-FF with quantitative 2D Dixon fat fraction (2D-Dixon-FF).
Material and methods: Ten adults aged ≥60 years were recruited prospectively received shoulder MRI. 2D-Dixon-FF and 3D-Dixon-FF were measured on 6-point Dixon fat fraction maps. 2D-GG was rated on T1-weighted images.
Results: The mean age of participants was 70.7 ± 3.7 years. The mean 3D-Dixon-FF was 8.3% ± 5.7%; the mean 2D-Dixon-FF was 7.3% ± 4.4%; and the mean 2D-GG was 0.9 ± 0.7. There was a strong correlation for 3D-Dixon-FF with 2D-Dixon-FF (rho = 0.90; P < 0.001) and with 2D-GG (rho = 0.73; P = 0.017). Excellent inter-observer reliability was found for Dixon fat fraction (intraclass correlation coefficient = 0.946), which was good for Goutallier grade (weighted kappa = 0.634).
Conclusion: Supraspinatus 3D-Dixon-FF had a strong correlation with 2D-Dixon-FF and 2D-GG in our study population.
Keywords: Intramuscular fatty infiltration; magnetic resonance imaging; quantitative; rotator cuff; shoulder.