Focal brachial enhancement deficit: a normal anatomic variant?

Area of Science:

• Radiology
• Musculoskeletal Imaging

Background:

• Brachialis enhancement deficits (BEDs) are observed on contrast-enhanced MRIs.
• The incidence and clinical significance of BEDs are not well-established.

Purpose of the Study:

• To determine the incidence of BEDs on contrast-enhanced elbow MRIs.
• To investigate the association between BEDs and patient symptoms, imaging findings, and positioning.

Main Methods:

• Review of 138 elbow MRIs (64 males, mean age 45.3 years).
• Assessment of BED presence, size, and enhancement.
• Recording of elbow flexion, forearm rotation, and other pathologies.

Main Results:

• BEDs were present in 54% of MRIs.
• No significant association found with age, gender, or presenting symptoms.
• Strong correlation between elbow flexion and BED presence (p<0.0001).
• Inverse correlation between BED size and elbow flexion (p<0.01).

Conclusions:

• BEDs are a common, likely asymptomatic finding on post-contrast elbow MRIs.
• Elbow flexion may cause diminished brachialis enhancement, possibly due to vascular compression.