Normal Mri Rotator Cuff

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The superior and inferior labra are visualized best on coronal oblique images, whereas the anterior and posterior labra are seen best on axial images (Figs. 14 and 15). A labral tear is diagnosed when an irregular line of fluid or intra-artic-ular contrast tracks into the labral substance or between the labrum and the glenoid articular cartilage (Fig. 16). When a labral tear extends through the joint capsule, a paralabral cyst may develop in an extra-articular location. The cyst may be the most apparent sign of a labral tear, and is a highly specific finding. Most often these cysts develop along the posterosuperior glenoid rim [14]. Displacement of the labrum away from the glenoid is another sign of a tear. When the labrum is displaced there may be stripping of the attached periosteum along the medial glenoid neck resulting in an anterior labral-liga-mentous periosteal sleeve avulsion lesion (Fig. 16B).

Unfortunately, the size, shape, and signal intensity of the normal labrum show variations that decrease accuracy in the diagnostic evaluation of labral injury on conventional MRI [15,16]. Most commonly the superior and anterior labra are triangular in shape whereas the posterior and inferior portions are rounded [13]. The superior labrum usually is larger than the inferior labrum and the posterior labrum usually is larger than the anterior labrum [4]. In the study by Zanetti and colleagues [16], arthroscopic findings were compared with findings on MR arthrograms in 55 patients. Only 50% of the arthroscopi-cally proven normal labral parts had the expected low signal intensity and triangular contour on MR images. In the same study, 31% of the arthroscopically normal labral parts had linear or globular high signal on MR arthrographic images, possibly because of myxoid changes of the labral substance [17]. Normal variants, such as attenuation, complete separation, and complete absence of the labrum, also contributed to diagnostic difficulty.

Because of the wide variation in labral appearance, caution must be used when diagnosing a labral tear on conventional MRI. This is true especially

Mri Labral Tear Anterior
Fig. 14. Normal anterior, posterior glenoid labrum. On PD axial image, both anterior (arrow) and posterior labra show normal contours and locations overlying the glenoid rim. The labrum is partially undercut by articular cartilage. H, humeral head.
Normal Shoulder Labrum Mri

Fig. 15. Normal superior labrum, labral-bicipital complex. Following intra-articular injection of contrast material, T1-weighted oblique coronal image (A) shows normal contour of superior (arrow) and inferior glenoid labra without sublabral leak of contrast material. More anteriorly (B), the superior labrum (curved arroW) shows normal relationship to biceps tendon (straight arrows).

Fig. 15. Normal superior labrum, labral-bicipital complex. Following intra-articular injection of contrast material, T1-weighted oblique coronal image (A) shows normal contour of superior (arrow) and inferior glenoid labra without sublabral leak of contrast material. More anteriorly (B), the superior labrum (curved arroW) shows normal relationship to biceps tendon (straight arrows).

of the anterior and anterior superior portions of the labrum where the most common normal variants occur. These variants include sublabral recess, subla-bral foramen, and congenital absence of the superior labrum.

A sublabral recess is diagnosed when a thin, smooth line of high signal is present between the articular cartilage and the superior labrum. The line of high signal should follow the contour of the glenoid and it should not extend posterior to the biceps anchor. If it is seen posterior to the biceps anchor a superior labral tear should be suspected [18].

Biceps Anchor Mri

Fig. 16. Bankart lesion and superior tear extension in 34-year-old patient with anterior instability. Following intra-articular injection of contrast material, T1-weighted axial image (A) shows contrast material completely undercutting the anterior glenoid labrum (arrow). On fat-suppressed T1-weighted oblique coronal image (B), the inferior labral-ligamentous complex (straight arrow) is thickened with mild medial displacement suggesting periosteal sleeve avulsion. The tear extends into the superior labrum (curved arrow). H, humeral head.

Fig. 16. Bankart lesion and superior tear extension in 34-year-old patient with anterior instability. Following intra-articular injection of contrast material, T1-weighted axial image (A) shows contrast material completely undercutting the anterior glenoid labrum (arrow). On fat-suppressed T1-weighted oblique coronal image (B), the inferior labral-ligamentous complex (straight arrow) is thickened with mild medial displacement suggesting periosteal sleeve avulsion. The tear extends into the superior labrum (curved arrow). H, humeral head.

Absence of the anterior superior labrum occurs in 2% of patients. When it is associated with a thickened middle glenohumeral ligament (MGHL) it is called a Buford complex [16]. Another variant that occurs in the anterior superior labrum is a sublabral foramen, a normal detachment of the labrum from the anterior superior glenoid. It is found in approximately 11% of patients and mimics a labral tear on MR images [4].

MR arthrography can overcome some of these diagnostic problems because it provides distention and separation of intra-articular structures and fills labral tears. The diagnostic accuracy of MR arthrography in diagnosing anterior inferior labral tears is greater than 90%. Additional imaging with the shoulder in abduction and external rotation (ABER position) can further improve anterior inferior labral evaluation [19-21]. In this position the anterior band of the inferior glenohumeral ligament is pulled taut and creates traction on the anterior inferior labrum [19]. If an anterior labral tear is present, the partially detached labrum is pulled away from the glenoid and contrast material fills the defect. The ABER position is achieved by flexing the elbow and placing the patient's hand behind the head [19]. Axial oblique imaging then is performed parallel to the long axis of the humerus.

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Responses

  • Faryl Davidson
    WHAT IS GLENOID LABRUM MYXOID DEGENERATION?
    8 years ago
  • portia
    How to interpret shoulder mri with contrast?
    8 years ago
  • ashley
    Where Is The Labrum In The Shoulder normal versus tear?
    7 years ago
  • melba diggle
    What is Superior labral myxoid degeneration?
    7 years ago
  • Leonie
    What Does Shoulder Mri Show?
    7 years ago
  • liisa
    What does a normal shoulder mri arthrogram look like?
    7 years ago
  • phillip
    What is a COMPLEX TEAR OF THE ANTERIOR LABRUM how is that different than a regular tear?
    6 years ago
  • BELLADONNA BROWN
    What mri shows shoulder?
    6 years ago
  • Kerstin
    What does an MRI with a torn rotary cuff look like?
    6 years ago
  • celendine
    What does a normal shoulder arthrogram show?
    6 years ago
  • belle munro
    How to read a shoulder MRI without contrast?
    6 years ago
  • DIRK KAPPEL
    What does a tear on the suprinatus on an mri t1 image look like?
    5 years ago
  • maire
    What does a shoulder posterial labral tear look like mri?
    5 years ago
  • pearl
    How to position aber shoulder mri?
    5 years ago
  • dennis
    What does torn labrum look like on a mri?
    5 years ago
  • Spartaco
    What should a healthy labrum of shoulder look like on MRI with dye?
    4 years ago
  • Armida
    What does a NORMAL rotator cuff look like on a mri?
    9 months ago
  • blair
    What does a shoulder tear look like on a MRI image?
    8 months ago
  • jonas mueller
    What does a heathy rotor cuff look like compared to one that doesnt look heathy?
    29 days ago

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