Magnetic resonance imaging-based quantitative definition of pathologic long head of the biceps tendon sheath…

Cohort studyJSES international· Sep 2026

Magnetic resonance imaging-based quantitative definition of pathologic long head of the biceps tendon sheath effusion and its association with intra-articular shoulder pathology.

Daisuke Yamashita, Takayuki Oishi, Taiki Nozaki … Nobuto Kitamura

Shoulder & ElbowCohort studyDiagnosisQ2IF 2.2

Pathologic biceps tendon sheath effusion strongly associated with long head biceps tendon lesions

Magnetic resonance imaging-based quantitative definition of pathologic long head of the biceps tendon sheath effusion and its association with intra-articular shoulder pathology.

Daisuke Yamashita … Nobuto Kitamura

JSES international · Sep 2026 · Q2 in Orthopedics

Background

There is no consensus regarding the pathologic significance of effusion within the long head of the biceps tendon sheath (LHB effusion), and its association with other shoulder joint pathologies remains unclear.

Purpose

The purpose of this study was to establish a quantitative magnetic resonance imaging-based threshold for pathologic LHB effusion and to investigate its associations with clinically relevant shoulder pathologies.

Methods

We retrospectively reviewed 261 shoulder magnetic resonance imaging examinations acquired between July 2019 and December 2020.

n = 261 shoulder MRI examinations

Results

biceps tendon lesions were far more likely with pathologic effusion

LHB lesion

4.37OR

Frozen shoulder

3.16OR

Older age

1.03OR

More results

The threshold values for pathologic LHB effusion area, determined based on the expert visual assessment of the shoulder surgeon and the musculoskeletal radiologist, were 18.13 and 19.29 mm 2 , respectively.

More results

DISCUSSION: Quantitative magnetic resonance imaging assessment of LHB sheath effusion demonstrated high measurement reproducibility, and an expert-derived threshold of approximately 19 mm 2 was associated with older age, LHB lesions, and frozen shoulder.

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Conclusion

Because the threshold was derived from expert visual assessment rather than an independent pathologic gold standard, these findings should be considered preliminary and require external validation before use as a diagnostic criterion.

Magnetic resonance imaging-based quantitative definition of pathologic long head of the biceps tendon sheath effusion and its association with intra-articular shoulder pathology.

Magnetic resonance imaging-based quantitative definition of pathologic long head of the biceps tendon sheath effusion and its association with intra-articular shoulder pathology.

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