A suggestion of reference data for flow distribution at ankle and foot level using quantitative 99Tc-HDP three-phase bone scintigraphy

Abstract

To determine reference intervals for quantitative 99mTc-hydroxymethylene diphosphonate (99mTc-HDP) three-phase bone scintigraphy regarding flow distribution at ankle and mid-foot level. Fifty patients referred to bone scintigraphy without known or suspected pathology in the legs or hips were included. Quantitative three-phase bone scintigraphy was performed in all patients. A processing protocol with standardized size regions of interests (ROIs) was used to quantify the distribution of flow and blood pool at ankle and level mid-foot levels. Patients were divided into three groups: <60 years (n = 20), 60 years or older (n = 17) and finally a group (n = 13) with pedal foci (PF). Blood pool distribution varied between the two age groups, with younger having the narrowest confidence interval at mid-foot level but the widest at ankle level. Blood flow distribution confidence intervals were wider in the presence of PF, whereas blood pool distribution intervals were independent of PF. Both blood flow distribution and blood pool at ankle and mid-foot level were independent of gender and referral status being either cancer or skeletal complaints. As there was no evident increase in blood flow distribution at ankle and mid-foot level with age, we suggest the use of pooled data from both age groups. Subsequently, the confidence interval for the relative distribution of blood flow at ankle level is 37/63 and 33/67 at mid-foot level. For blood pool, the corresponding intervals are 43/57 and 40/60, respectively. Blood flow distribution appears to be influenced by the presence of PF, whereas blood pool distribution is not.