Imaging Guidelines for Shoulder Pain

Clinical History that Directs Imaging

The mechanism of injury (acute vs. chronic) helps differentiate fracture, dislocation, rotator‑cuff injury, or labral pathology. American College of Radiology recommendation. 3
Age and demographics influence the differential: young males are more prone to traumatic injuries, whereas older patients more often have degenerative rotator‑cuff disease. American College of Radiology recommendation. 3

Plain radiography with at least three upright views (AP internal rotation, AP external rotation, and axillary or scapula‑Y) is the first‑line study for every patient with shoulder pain, irrespective of suspected cause. American College of Radiology recommendation. [1][2]
Upright positioning is essential because supine films may underestimate malalignment. American College of Radiology recommendation. [4][3]
Axillary or scapula‑Y views are required to avoid missing acromioclavicular or glenohumeral dislocations that can appear normal on AP views alone. American College of Radiology recommendation. [4][3]

CT shoulder (non‑contrast) is advised for detailed bone assessment and detection of subtle nondisplaced fractures. American College of Radiology recommendation. [1][2]
MRI shoulder (non‑contrast) can demonstrate bone‑marrow edema from trauma and concurrently evaluate soft‑tissue injuries such as rotator‑cuff or labral tears. American College of Radiology recommendation. [1][2]

CT shoulder (non‑contrast) should be performed to delineate fracture planes and assist surgical planning. American College of Radiology recommendation. [1][2]
MRI is less optimal for fracture characterization but may be useful when assessing associated rotator‑cuff injury in patients not slated for operative fixation. American College of Radiology recommendation. [1][2]

MRI shoulder (non‑contrast) is the primary advanced modality for evaluating soft‑tissue structures in dislocation/instability. American College of Radiology recommendation. [1][2]
In acute dislocation, the post‑traumatic joint effusion or hemarthrosis provides natural contrast, eliminating the need for arthrography. American College of Radiology recommendation. [1][2]
CT shoulder (non‑contrast) can be used when MRI cannot adequately assess bone loss. American College of Radiology recommendation. [1][2]
MR arthrography is reserved for detailed labral assessment in sub‑acute or chronic cases where joint effusion is insufficient. American College of Radiology recommendation. [1][2]

Acute trauma: MRI shoulder (non‑contrast) is preferred over MR arthrography because the effusion provides adequate joint distention. American College of Radiology recommendation. [1][2]
Sub‑acute/chronic: MR arthrography is the reference standard when the effusion is too small for optimal soft‑tissue visualization. American College of Radiology recommendation. [1][2]
CT arthrography is appropriate for patients who cannot undergo MRI. American College of Radiology recommendation. [1][2]

Either MRI shoulder (non‑contrast) or ultrasound may be used; only one study is required. American College of Radiology recommendation. [1][2]
MRI is favored in patients with large body habitus, limited motion from acute pain, or when concurrent intra‑articular pathology (e.g., labral tear) is suspected. American College of Radiology recommendation. [1][2]
Both MRI and ultrasound demonstrate high sensitivity (≈90‑91 %) and specificity (≈93‑95 %) for full‑thickness rotator‑cuff tears. American College of Radiology recommendation. 2
Ultrasound performance for partial‑thickness tears is variable, with inconsistent inter‑observer agreement. American College of Radiology recommendation. 2
Ultrasound may be chosen over MRI when metallic hardware creates susceptibility artifacts that limit MRI quality. American College of Radiology recommendation. 2

Do not rely solely on AP views for traumatic shoulder assessment; dislocations are frequently missed without axillary or scapula‑Y views. American College of Radiology recommendation. [4][3]
Do not order CT as the initial study; standard radiography reliably identifies displaced fractures and malalignment, which are the primary acute management concerns. American College of Radiology recommendation. [4][3]
Avoid MR arthrography in acute trauma because natural joint effusion/hemarthrosis supplies sufficient contrast for soft‑tissue evaluation. American College of Radiology recommendation. [1][2]
Do not assume ultrasound can replace MRI for all soft‑tissue pathology; its utility is limited for deep structures and labral lesions. American College of Radiology recommendation. [4][5]6