Back to Course

Remote Fellowship – Foot & Ankle Fundamentals – 11/2/2020

0% Complete

Diagnosis

Gout

Case Discussion

Gout is a crystalline deposition disorder characterized by deposition of crystalline urate around joints and other periarticular soft tissue sites (including tendons and bursa). The deposition of these crystals triggers a cytokine-mediated inflammatory reaction leading to cartilage destruction, osseous erosions, and soft tissue tophi involving tendons and juxta-articular soft tissue.

Gout has a strong male predilection (20: 1), usually occurring after the age of 40, unless there is an underlying condition predisposing to hyperuricemia (such as leukemia, chronic renal disease, or an inborn error of metabolism).

Gout is typically an asymmetrical polyarticular arthropathy, most commonly involving the 1st metatarsophalangeal joint. Other locations include the ankles, heels, wrists, fingers, knees and elbows.

Findings of gout on MRI include well defined, marginal erosions with overhanging edges; intermediate T1 signal intensity within the adjacent soft tissues (indicative of gouty tophi); and marrow edema with bony cystic changes subjacent to marginal erosions on T2-weighted images. Gouty tophi appear as isointense or low signal masses on T1 and variable signal intensity on T2. 

Gout is notorious for infiltrating tendons and less commonly ligaments. It has a propensity to infiltrate this Achilles Tendon of the ankle, the Patellar Tendon of the knee, Quadriceps Tendon of the knee, and Popilteus Tendon and the Popliteus Hiatus of the knee. 

Key Images

Gout in a 46-year-old man with a history of gout, complaining of enlargement and stiffness of the right great toe.

A. Coronal T2 FS image of the right foot shows a large mass with predominantly low signal intensity along the dorsal aspect of the first metatarsophalangeal joint, consistent with tumefactive gouty tophus (red arrow).
B. Sagittal T1 FS image shows a large mass with predominantly low signal intensity along the dorsal aspect of the first metatarsophalangeal joint (red arrow).  A large underlying pressure-type erosion with overhanging edges is seen at the dorsal aspect of the first metatarsal head (green arrow)

References

  1. Girish G, Glazebrook KN, Jacobson JA. Advanced imaging in gout. American Journal of Roentgenology 2013; 201:515-525
  2. Yu JS, Chung C, Recht M, Dailiana T, Jurdi R. MR imaging of tophaceous gout. American Journal of Roentgenology 1997; 168:523-527