FIESTA: An MR arthrography celebration of shoulder joint anatomy, variants, and their mimics

Abstract

Magnetic resonance (MR) arthrography is currently the gold standard radiological investigation for shoulder joint instability. Not only does this investigation allow for identification of important disease processes, but the reduced slice thickness and increased in-plane resolution allowed by the latest imaging sequences also gives excellent demonstration of shoulder joint internal anatomy. This article describes the technique of MR arthrography of the shoulder practiced at our institution, briefly outlining features of the FIESTA (fast imaging employing steady state acquisition) MR sequence employed, including its advantages and limitations. A pictorial review of shoulder MR arthrography performed with this technique is presented, concentrating on normal shoulder joint internal anatomy and anatomical variants that may mimic pathology.

What can the Radiologist do to Help the Surgeon Manage Shoulder Instability?

“…Findings suggestive of a SLAP tear include a high signal intensity that is globular, irregular or laterally curved into the substance of the labrum on coronal oblique images, an anterior to posterior linear hyperintense signal on axial T1-weighted MR arthrography (MRA), a signal of irregular width measuring > 2 mm. Because contrast material or joint fluid will extend under the free edge of a meniscoid-type superior labrum, it may be mistaken for a labral tear [ 1 3 4 11 14 21 25 26 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 ].…”

“…These anterosuperior variants may also predispose to superior labral lesions. Differentiating these normal variants from pathology is crucial because fixing the normal labrum and/or the middle glenohumeral ligament will result in loss of external rotation and surgical failure [ 1 3 9 14 25 30 32 33 34 35 36 37 38 39 40 44 46 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 ].…”

MR Arthrography of the Shoulder: Technical Update and Clinical Applications

“…Most anatomical variants are observed in the anterosuperior quadrant [115][116][117][118][119][120][121][122][123][124] and include the sublabral recess/sulcus, the sublabral foramen/hole, and the Buford complex. The junction between the hyaline cartilage of the glenoid and the labrum can create a pseudotear in the labrum.…”

Anatomy, Variants, and Pathologies of the Superior Glenohumeral Ligament: Magnetic Resonance Imaging with Three-Dimensional Volumetric Interpolated Breath-Hold Examination Sequence and Conventional Magnetic Resonance Arthrography

“…Sagittal oblique MR arthrography shows that the SGHL is located underneath the coracoid process and CHL. A normal foramen exists between the SGHL and the MGHL, allowing communication of the glenohumeral joint cavity through the subscapularis recess (1, 3, 17, 18). …”

“…8), it usually presents as a thick structure when the MGHL is absent or undeveloped (Figs. 9, 10) (16, 18, 19, 20). The SGHL is consistently identified as capsular ligament by MR arthrography and arthroscopy examination.…”