CASE 6

Bone scan (Blood pool)

Bone scan (Delayed)

By: Dr. Saleh Othman, MD, MSc, JMCB

HISTORY: 44 years, female, with left hand pain of three months duration and no known history of trauma. X-ray reduced bone density in left forearm and hand bones. Bone scan requested to determine possible cause.

FINDINGS:

Three-phase bone scan shows increased blood flow and blood pool in whole left forearm and hand in particular left wrist joint. Delayed image showed increased uptake in left wrist joint and small joint of left hand.

Scan findings and considering clinical and x-ray (osteopenia) bone scan compatible with RSDS.

DIAGNOSIS:

Reflex sympathetic dystrophy (RSDS): (Sudeck’s Atrophy).

PEARLS AND DISCUSSION:

RSD is a complex of signs and symptoms characterized by pain, tenderness, vasomotor instability, swelling and dystrophy changes. It can be caused by trauma, arthritis, tendinitis, infection, tumor, herpes zoster, myocardial infarction and herniated lumbar disk. It can affect both upper and lower limbs. Conventional x-ray may show reduced bone density.

Teaching points:

• Changes on the x-ray are not specific.

• Bone scan findings depend on the stage of the disease. In stage one (first 20 weeks) all three phases are positive. In stage 2 (20-60 weeks) blood flow is normal while blood pool and delayed uptake are increased. And in stage 3 (after 60 weeks) blood flow reduced and blood pool and delayed uptake are normal.

• Positive bone scans often return to normal following steroid therapy.

• Bone scan sensitivity 96% and specificity 97%.

FURTHER READING:

1. Kwon, Hyun Woo et al. “Diagnostic Performance of Three-Phase Bone Scan for Complex Regional Pain Syndrome Type 1 with Optimally Modified Image Criteria.” Nuclear Medicine and Molecular Imaging 45.4 (2011): 261–267. PMC. Web. 29 Dec. 2016.