J Korean Soc Magn Reson Med.  2014 Sep;18(3):193-199. 10.13104/jksmrm.2014.18.3.193.

Superior Labral Dimension of the Glenohumeral Joint on Direct MR Arthrography (MRA): Relationship with Presence of SLAP (Superior Labrum Anterior to Posterior) Lesion

• Im TS
• Choi JA
• Oh JH

• KMID: 1999918
• DOI: http://doi.org/10.13104/jksmrm.2014.18.3.193

Abstract

PURPOSE
To evaluate the relationship between superior labral dimension of the glenohumeral joint on direct MRA and presence of SLAP lesion.
MATERIALS AND METHODS
IRB approval was obtained and informed consent was waived for this retrospective study. Direct MRA studies of the shoulder in 296 patients (300 shoulders) with arthroscopic surgery were analyzed by two radiologists blinded to the arthroscopic results, which were used as gold standard. One of the radiologists reviewed the images twice (session 1 and 2) for the evaluation of intra-observer variability. Transverse and longitudinal dimensions of superior labrum on coronal T1-weighted images were measured as base and height of the inverted triangular-shaped superior labrum and compared between patients with SLAP lesions vs. non-SLAP patients. Presence of meniscoid labrum was noted. Statistical analysis was done using unpaired t-test.
RESULTS
Among 279 patients (283 shoulders), 122 patients (43.1%) had SLAP lesions. The mean base/height of superior labrum in SLAP and non-SLAP patients measured on T1-weighted MR image were 8.8 mm / 5.2 mm, 8.5 mm / 4.9 mm for reader 1; 8.2 mm / 4.9 mm, 8.1 mm / 4.5 mm for session 1 of reader 2; 8.0 mm / 4.8 mm, 7.6 mm / 4.3 mm for session 2 of reader 2. In SLAP group, the mean labral height was larger than non-SLAP group with statistically significant difference (p<0.05). Fifteen patients (5.3%) had meniscoid labrum according to operation records.
CONCLUSION
In patients with SLAP lesion, the height of the superior glenoid labrum on oblique coronal image of MRA was slightly larger than non-SLAP patients. A larger height of superior glenoid labrum may be associated with SLAP lesions.

Keyword

Labrum; Glenohumeral joint; Superior labrum anterior to posterior (SLAP); Magnetic resonance imaging (MRI)

MeSH Terms

Arthrography*
Arthroscopy
Ethics Committees, Research
Humans
Informed Consent
Observer Variation
Retrospective Studies
Shoulder
Shoulder Joint*

Figure

• 

  Fig. 1 Measurement of superior labral dimension. (a) Superior labral dimension is measured on the plane where long head of biceps looks smallest and labrum largest twelve o'clock position. Transverse and longitudinal dimensions are obtained by measuring base (solid line) and height (dotted line) of inverted triangular shaped labrum. (b) On T1-weighted oblique coronal MRI, the base and height of the superior labrum are measured.

• 

  Fig. 2 65-year-old female with rotator cuff tear. (a) Triangular shaped superior labrum attached to glenoid rim is seen on oblique coronal T1-weighted MR image. The height of the labrum is measured to be 6.4 mm. (b) There is neither meniscoid labrum nor SLAP on arthroscopy.

• 

  Fig. 3 55-year-old female with rotator cuff tear and SLAP. (a) The height of labrum is measured to be 10.3 mm on oblique coronal T1-weighted MR image. It is considered to be larger than usual. (b) On arthroscopy, both meniscoid labrum (white arrow) and SLAP (black arrow) are detected. The superior labrum is covering upper quarter of the glenoid.

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