Effect of growth hormone on metaphyseal uptake of 99mTc-methylene diphosphonate

Eight children with short stature and GH deficiency were studied with 99mTc-methylene diphosphate before, during (occasionally), and after 4 months of GH therapy. Using digital images of the femoral shaft and distal metaphysis, the percent change in metaphysis-to-shaft, metaphysis-to-background (muscle), and metaphysis-to-injected dose ratios were calculated and compared to percent change in growth velocity over 4 months. The percent change in metaphysis-to-shaft and metaphysis-to-background ratios showed no significant correlation with percent change in growth velocity. The percent change in metaphysis-to-dose ratio demonstrated a significant correlation with change in growth velocity (r = 0.66; P less than 0.05). In addition, five of six patient studies before 4 months (after 1-68 days of GH therapy) demonstrated an increased metaphysis-to-dose ratio compared to baseline. In conclusion, GH therapy in GH-deficient children appears to increase the uptake of 9mmTc-methylene diphosphonate in the metaphysis, shaft, and muscle to a similar extent, and this increase appears to occur in most patients early after initiation of therapy.