High Signal in Tendons

High signal may be seen in normal tendons:

• Quadriceps and distal triceps tendons: Longitudinal striations with intermediate signal
• Midsubstance of Achilles tendon: Thought to represent the apposition of the soleus and gastrocnemius tendons.
• At osseous insertions, where tendon fibers fan out
• Magic angle artifact (~55 degrees)

Abnormalities associated with high signal in tendons:

• Myxoid degeneration (often coexist with partial tears)
• Partial or complete tear
• Xanthoma
• Gout
• Tumor

References

Helms et al. Musculoskeletal MRI. Second edition. p 51.