Quantitative Ultrashort Echo-Time MRI to Assess In Vivo Rotator Cuff Tendon Quality

Rotator cuff tears are a common source of pain and disability. Surgical treatment outcomes can be influenced by tendon quality, but conventional MRI does not allow for objective assessment of tendon degeneration. This work aims to develop and evaluate quantitative ultra-short echo-time (UTE) MRI methods to assess rotator cuff tendon quality in vivo. Followed by a validation study using bovine tendons, five volunteers, twelve patients with rotator cuff surgeries, and twelve age- and sex-matched healthy controls were scanned on a 3 T GE Signa Premier scanner. For the patients and control subjects, participant-reported outcome measures were obtained. Clinical shoulder MRI was performed to characterize tendon pathology. Quantitative imaging included multi-echo UTE Cones and magnetization transfer (MT)-prepared UTE Cones. Multi-echo UTE Cones images were used for both mono-exponential fitting (T₂*_m) and bi-exponential fitting (deriving short and long T₂* (T₂*_s, T₂*_l) and the fraction of T₂*_s component (f_s)). In the specimen study, MMF showed minimal orientation dependence compared with T₂*-based parameters. Between the patient and the matched control groups, significant differences were observed for the mean T₂*_m, f_s, and MMF. Moderate correlations were observed between these quantitative metrics and outcome measures (0.37 $\le$ |r|  $\le$ 0.63). Increasing pathological severity was associated with elevated T₂*_m and reduced MMF values. Quantitative UTE-based measurements, particularly T₂*_m and MMF, are sensitive to tendon degeneration and correlate with clinical outcomes. These biomarkers may support improved surgical decision-making and monitor tendon healing process.