Normal Variants and Artifacts

Abstract

Recalling the expression “all is not gold that glitters”, increased uptake is not necessarily pathological. Indeed, normal bone scintigraphs are often altered or modified by physiological or anatomical factors, imitating pathology (Howarth et al. 1996). For example, the tuberosity of the humerus and proximal tibia, to which the deltoid and quadriceps muscles are attached, respectively, may accumulate tracer intensely due to constant physical stress. Tracer uptake is normally increased in growing bones, either locally in the physes (Figs. 4.13 and 4.15) or generally in the entire skeleton, and also in anatomical variants. Modest tracer uptake may be observed in secondary ossification centers that have recently been fused (Fig. 4.31A). A number of artifacts can be produced by various technical factors related to kit preparation or intravenous injection of radiopharmaceuticals, attenuation of gamma rays, or the function of the gamma camera and computer systems (Hung et al. 1996; Forstrom et al. 1996; O’Connor 1996).