Presentation
47 years-old-male presenting with medial left foot pain and swelling.
Patient Data
Series 1 demonstrates the frontal views of both angiographic and blood phases. There is focal hyper perfusion on the angiographic phase and hyperemia on the blood pool phase on the medial aspect of the left forefoot.
Series 2 demonstrates the lateral projection of both feet. There is focal hyperemia involving the soft tissue surrounding the left first metatarsophalangeal joint.
Series 3 shows anterior, plantar and medial projections of the feet. There is high grade activity involving the sesamoid bones around the left first MTP joint with moderate activity involving both left 1st metatarsal and left big toe proximal phalanx.
The diagnosis is sesamoiditis and left 1st MTP septic arthritis.
Case Discussion
A triphasic bone scan is an extremely sensitive test for the diagnosis of osteomyelitis. The coexistent of underlying bony pathologies hinder this test's specificity and may necessitate the use of alternative test such as nuclear WBC labeled scan or MRI, however in a non-violated bone a triphasic bone scan can give the diagnosis of osteomyelitis with a high confidence.
The initial angiographic phase reflects the relative amount of blood flow to the area of interest, whereas the blood pool phase indicates the amount of activity that has extravasated into the tissues around the area of interest. The delayed bone phase reflects the rate of bone turnover. The classic appearance of osteomyelitis on three-phase bone scan consists of focal hyperperfusion, focal hyperemia, and focally increased bone uptake