What can be visualized on a computed tomography (CT) scan of the shoulder without contrast?

What Can Be Visualized on CT Shoulder Without Contrast

CT shoulder without contrast excels at detecting and characterizing bone abnormalities—including subtle fractures, complex fracture patterns, and bone loss—but cannot assess soft tissue structures like rotator cuff tears, labral injuries, or ligamentous pathology that are frequently the source of shoulder pain and dysfunction. 1

Primary Strengths: Bone Evaluation

Fracture Detection and Characterization

• CT is superior to radiography for identifying subtle nondisplaced fractures that may be missed on plain films, particularly in complex anatomical regions 1
• CT characterizes fracture morphology in complex comminuted fractures where radiographs are indeterminate, with studies showing CT changes clinical management in up to 41% of patients with proximal humeral fractures 1
• CT is the most useful modality for detecting scapular fractures, especially nondisplaced ones that are frequently missed on radiographs 1
• CT best evaluates intraarticular extension, angulation, and lateral border offset in scapular fractures compared to conventional radiographs 1
• Three-dimensional CT reconstructions better visualize fracture displacement and angulation, particularly for scapular fractures 1, 2

Bone Loss and Defects in Instability

• CT historically has been used to assess Hill-Sachs lesions and bony Bankart lesions that are frequently underestimated or missed on radiographic examination 1
• CT provides excellent assessment of glenoid bone loss and humeral head bone defects with high spatial resolution 2, 3
• CT can detect glenoid surface abnormalities including fragmentation, fracture, and irregularity in patients with shoulder dislocations 4
• CT can identify abnormal glenoid-scapular angles that may contribute to instability 4
• CT can detect loose bodies and coracoid fractures associated with shoulder trauma 4

Critical Limitations: Soft Tissue Evaluation

What CT Cannot Assess

• CT cannot evaluate rotator cuff tears, which are common sources of shoulder pain, especially in older adults 1, 2
• CT is unable to assess labroligamentous complex injuries (Bankart lesions) without arthrography 1, 2
• CT is limited in assessing cartilaginous Hill-Sachs lesions (only bony components are visible) 1, 2
• CT cannot demonstrate capsular or labral abnormalities without intraarticular contrast 4
• CT cannot assess rotator cuff and labroligamentous pathology commonly seen in shoulder dislocations and instability 1

Clinical Implications

• MRI has been shown to be equivalent to CT for assessing both glenoid and humeral head bone loss, making MRI preferable when soft tissue evaluation is also needed 1
• CT should be reserved for patients in whom MRI assessment of bone loss is limited (e.g., contraindications to MRI or hardware artifact) 1, 2

When CT Without Contrast Is Appropriate

Primary Indications

• After indeterminate radiographs when detailed fracture characterization is needed for surgical planning 1
• For scapular fracture evaluation where CT is the best modality 1
• When MRI cannot be performed due to metallic hardware or other contraindications and bone assessment is the primary concern 2
• For quantifying bone loss in instability when MRI is contraindicated 2

Important Caveats

• CT without contrast has no role in evaluating suspected labral tears as a next imaging study 1
• CT without contrast has no role in evaluating suspected rotator cuff tears as a next imaging study 1
• If soft tissue evaluation is needed and MRI is contraindicated, CT arthrography should be considered instead of noncontrast CT 2
• Ultrasound may be preferred over CT for evaluating rotator cuff pathology when hardware artifacts limit MRI 2