Three‐phase [^99mTc]diphosphonate scintimetry in septic and nonseptic arthritis of the immature knee: An experimental investigation in dogs

Abstract

We compared the informative value of dynamic and static [99mTc]diphosphonate ([99mTc]DPD) scintimetry in early septic arthritis (SA) and chronic nonseptic arthritis (NSA) of the knee in puppies. SA (n = 10), induced by injection of Staphylococcus aureus into one knee, was examined after 48 h. NSA (n = 6) was induced by weekly intraarticular instillation of 1% carrageenan and examined at 2 and 12 weeks. Epiphyseal and metaphyseal count ratios (CRs) between experimental and control joint were calculated in an angiographic phase (0-20 s), a "blood pool" phase (20-256 s), and a bone uptake phase (2 hs). Control dogs (n = 4) had a CR of 1.0 in all regions and phases, the coefficients of variation being 0.06 and 0.03 in dynamic and static phases, respectively. In NSA, all scintimetric phases showed decreased metaphyseal uptake and largely unchanged epiphyseal uptake. Generally, SA exhibited vastly increased angiographic uptake in all regions and increased epiphyseal blood pool uptake, whereas delayed epiphyseal uptake varied and delayed metaphyseal uptake tended to decrease. Two septic joints had generalized reduction in dynamic uptake, probably owing to increased intraarticular pressure; in one of these, dynamic uptake in the distal femoral epiphysis (FE) was totally absent, suggesting temporary circulatory arrest during the dynamic scanning procedure. The use of regional dynamic and static [99mTc]DPD scintimetry increased the pathophysiologic and diagnostic value of joint scintigraphy, especially with respect to the early detection of SA and its avascular complications.

[99mTc]diphosphonate uptake and hemodynamics in arthritis of the immature dog knee

“…[%"Tc]DPD uptake distribution agrees with our previous findings in experimental arthritis (17,18) and chronic hemarthrosis (16) using gamma camerabased [w"Tc]DPD joint imaging and contact autoradiography. However, details such as the increased patellar uptake, the uptake distribution between central and peripheral epiphyseal bone, and the increased metaphyseal uptake at a distance from the joint could not be appreciated by in vivo joint imaging.…”