Evaluation of the Subscapularis Tendon Tears on 3T Magnetic Resonance Arthrography: Comparison of Diagnostic Performance of T1-Weighted Spectral Presaturation with Inversion-Recovery and T2-Weighted Turbo Spin-Echo Sequences

Abstract

Objective: To compare the T1-weighted spectral presaturation with inversion-recovery sequences (T1 SPIR) with T2-weighted turbo spin-echo sequences (T2 TSE) on 3T magnetic resonance arthrography (MRA) in the evaluation of the subscapularis (SSC) tendon tear with arthroscopic findings as the reference standard.

Materials and methods: This retrospective study included 120 consecutive patients who had undergone MRA within 3 months between April and December 2015. Two musculoskeletal radiologists blinded to the arthroscopic results evaluated T1 SPIR and T2 TSE images in separate sessions for the integrity of the SSC tendon, examining normal/articular-surface partial-thickness tear (PTTa)/full-thickness tear (FTT). Diagnostic performance of T1 SPIR and T2 TSE was calculated with arthroscopic results as the reference standard, and sensitivity, specificity, and accuracy were compared using the McNemar test. Interobserver agreement was measured with kappa (κ) statistics.

Results: There were 74 SSC tendon tears (36 PTTa and 38 FTT) confirmed by arthroscopy. Significant differences were found in the sensitivity and accuracy between T1 SPIR and T2 TSE using the McNemar test, with respective rates of 95.9-94.6% vs. 71.6-75.7% and 90.8-91.7% vs. 79.2-83.3% for detecting tear; 55.3% vs. 31.6-34.2% and 85.8% vs. 78.3-79.2%, respectively, for FTT; and 91.7-97.2% vs. 58.3-61.1% and 89% vs. 78-79.3%, respectively, for PTTa. Interobserver agreement for T1 SPIR was almost perfect for T1 SPIR (κ = 0.839) and substantial for T2 TSE (κ = 0.769).

Conclusion: T1-weighted spectral presaturation with inversion-recovery sequences is more sensitive and accurate compared to T2 TSE in detecting SSC tendon tear on 3T MRA.

Keywords: Arthroscopy; Magnetic resonance arthrography; Magnetic resonance imaging; Subscapularis; Tear; Tendon.

Fig. 1. 67-year-old woman with arthroscopically confirmed articular-sided partial-thickness SSC tendon tear.

T1-weighted spectral presaturation with inversion-recovery axial (A) and oblique sagittal (B) images and T2-weighted turbo spin-echo axial (C) and oblique sagittal (D) images demonstrate localized contrast leakage onto uppermost facet of lesser tuberosity (arrows). Large contrast-filled defect caused by complete tear of supraspinatus and infraspinatus tendons (arrowheads) is also noted. SSC = subscapularis

Fig. 2. 64-year-old man with full-thickness SSC tendon tear diagnosed by arthroscopy.

T1-weighted spectral presaturation with inversion-recovery axial (A) and oblique sagittal (B) images and T2-weighted turbo spin-echo axial (C) and oblique sagittal (D) images reveal discontinuity of the tendon (arrows) with medial retraction.

Fig. 3. Flowchart of arthroscopic results.

SSCT = subscapularis tendon, SST = supraspinatus tendon

Fig. 4. 68-year-old man with articular-sided partial-thickness SSC tendon tear confirmed by arthroscopy.

A, B. T1-weighted spectral presaturation with inversion-recovery axial (A) and oblique sagittal (B) images show focal contrast-filled defect in undersurface of uppermost footprint of SSC tendon (arrows), which was diagnosed as partial-thickness tear by both readers. C, D. T2-weighted turbo spin-echo axial (C) and oblique sagittal (D) images show slightly increased signal intensity of SSC tendon without fluid-equivalant signal defect (arrows), which was underdiagnosed as normal by both readers.

Fig. 5. 68-year-old man with arthroscopically diagnosed full-thickness SSC tendon tear.

A, B. T1-weighted spectral presaturation with inversion-recovery axial (A) and oblique sagittal (B) images show detachment of SSC tendon from lesser tuberosity with contrast filling (arrows). Superficial “bridging fiber” remains without retraction, which have continuity with fibers overlying bicipital groove and anterior-most fibers of supraspinatus tendon (arrowheads). Both readers underdiagnosed as partial-thickness SSC tear. Accompanied full-thickness supraspinatus tendon tear (asterisk) with contrast leakage into subacromial-subdeltoid bursal space is also shown.