Quantitative MRI in patients with gluteal tendinopathy and asymptomatic volunteers: initial results on T1- and T2*-mapping diagnostic accuracy and correlation with clinical assessment.

Abstract

To determine if T1- and T2*-mapping of the gluteal tendons can discriminate between participants with and without clinical findings of gluteal tendinopathy (GT) and if they correlate with clinical assessment. This prospective study was conducted between January and December 2016. MRI of the hip included spin echo, short-T1 inversion recovery, variable-flip angle, and variable echo-time gradient echo sequences. MRI studies were reviewed independently by two radiologists. Two other readers segmented the gluteal tendons and T1, mono- (T2*m) and bi-exponential T2* (short (T2*s) and long (T2*l) components) were computed. Ten participants with GT (median age; interquartile range: 63 (57-67) years, all women) and 9 participants without GT (57 (55-59) years, 8 women) (P = 0.06) were enrolled. The sensitivity and specificity of reader 1 for disease classification were 40% (95% confidence interval (CI): 17-61%) and 70% (CI: 47-91%), and those of reader 2 were 70% (CI: 43-86%) and 80% (CI: 53-96%), with fair inter-reader agreement (Kappa = .38). T1 values could not discriminate between the two groups. The gluteal tendons T2*m and T2*s showed diagnostic accuracy ranging from .80 to .89. The posterior gluteus medius tendon T2*m and T2*s respectively showed sensitivity and specificity of 90%, and strong correlation (Spearman's rho = -.71; P = 0.02) with the Lower Extremity Functional Scale score. Quantitative MRI could help gain new insight into healthy and diseased gluteal tendons to allow better diagnosis and treatment stratification for patients.