Detection and Quantitative Assessment of Arthroscopically Proven Long Biceps Tendon Pathologies Using T2 Mapping

Abstract

This study evaluates how far T2 mapping can identify arthroscopically confirmed pathologies in the long biceps tendon (LBT) and quantify the T2 values in healthy and pathological tendon substance. This study comprised eighteen patients experiencing serious shoulder discomfort, all of whom underwent magnetic resonance imaging, including T2 mapping sequences, followed by shoulder joint arthroscopy. Regions of interest were meticulously positioned on their respective T2 maps, capturing the sulcal portion of the LBT and allowing for the quantification of the average T2 values. Subsequent analyses included the calculation of diagnostic cut-off values, sensitivities, and specificities for the detection of tendon pathologies, and the calculation of inter-reader correlation coefficients (ICCs) involving two independent radiologists. The average T2 value for healthy subjects was measured at 23.3 ± 4.6 ms, while patients with tendinopathy displayed a markedly higher value, at 47.9 ± 7.8 ms. Of note, the maximum T2 value identified in healthy tendons (29.6 ms) proved to be lower than the minimal value measured in pathological tendons (33.8 ms), resulting in a sensitivity and specificity of 100% (95% confidence interval 63.1-100) across all cut-off values ranging from 29.6 to 33.8 ms. The ICCs were found to range from 0.93 to 0.99. In conclusion, T2 mapping is able to assess and quantify healthy LBTs and can distinguish them from tendon pathology. T2 mapping may provide information on the (ultra-)structural integrity of tendinous tissue, facilitating early diagnosis, prompt therapeutic intervention, and quantitative monitoring after conservative or surgical treatments of LBT.

Keywords: T2 mapping; arthroscopy; long biceps tendon; tendinopathy.

Figure 1

Axial (A) and oblique coronal (B) proton-density-weighted sequences showing the slice positioning (white line in (A)) used to place the region of interest (ROI). As outlined by the white circle in (B), the sulcal portion of the long biceps tendon was chosen as the primary region of interest and subsequently transferred onto a color-coded T2 map.

Figure 2

Boxplots of overall T2 mapping values (ms) in healthy labrum and patients with LBT lesion. Note the complete separation of T2 values between patients with LBT lesions and healthy subjects.

Figure 3

(A) A coronal proton-density-weighted fat-saturated magnetic resonance image of a 59-year-old man with morphologically normal-appearing and arthroscopically proven healthy tendon of the long biceps head (arrow). (B) A merged image of the proton-density-weighted images and the corresponding color-coded T2 maps with the placed ROI in the sulcal portion of the LBT (white frame). The average T2 mapping value was 21.3 ms.

Figure 4

(A) A coronal proton-density-weighted fat-saturated magnetic resonance image of a 58-year-old man with focal hyperintensity of the sulcal portion of the LBT (arrow). (B) A merged image of the proton-density-weighted images and the corresponding color-coded T2 maps with the placed ROI in the sulcal portion of the LBT (white frame). Note the elevated average T2 mapping value of 44.7 ms. During the arthroscopy, a partial tear of the LBT was found.

Figure 5

(A) A coronal proton-density-weighted fat-saturated magnetic resonance image of a 57-year-old man with longitudinal hyperintensity of the sulcal and the partially depicted extraarticular portion of the LBT with a markedly increased tendon diameter (arrow). (B) A merged image of the proton-density-weighted images and the corresponding color-coded T2 maps with the placed ROI in the sulcal portion of the LBT (white frame). Note the elevated average T2 mapping value of 52.8 ms. During the arthroscopy, a longitudinal partial tear was found.