Scintimetric study on serial change with Tc-99m-MDP following fractures of long bone in lower limb

Abstract

Bone scan has been employed to monitor the fracture healing in recent years. The findings of radioisotope uptake have been interpretated, however, usually optically, lacking the objective numerical presentation. We introduced pixel counting method with computer to interpretate the uptake ratio of Tc-99m-MDP on fracture site more objectively. The purpose of present study was to see whether delayed union or nonunion in certain: long bone fractures could be detected earlier with bone scan than the usual clinical and radiological examinations following fractures. Serial bone scan study was performed with Tc--99m-MDP in 22 cases of femoral shaft. fracture and 26 cases of tibial shaft fracture that were also followed clinically and radiologically at Korea university hospital from January, 1984 to June, 1985. Serial observations. of Tc-ggm-MDP uptake ratio were analized by pixel counting method with computer from 1 week to 18 months after injury. The results obtained were as follows: 1. In normal union group following femoral shaft fractures, the mean uptake ratio of Tc-99m-MDP was 2.400.33 at 1 week after injury and increased rapidly to a maximal´ value of 6.67-1.04 at 1 month, 6.130.76 at 4 months and decreased, thereafter, up to, 18 months. 2. In normal union group following tibial shaft fractures, the mean uptake ratio of Tc-99s m-MDP was 2.310.35 at 1 week after injury and increased rapidly to a maximal value of 5.901.20 at 2 months, 5.831.18 at 4 months and decreased, thereafter, up to 18 months.. 3. In delayed union group following femoral shaft fractures, the mean uptake ratio of Tc-99m-MDP was 2.030.71 at 1 week after injury and increased slowly to a maximal value of 4.570.78 at 12 months and decreased, thereafer, up to 18 months. 4. In delayed union group following tibial shaft fractures, the mean uptake ratio of Tc-99m-MDP was 1.910.27 at 1 week after injury and increased slowly to a maximal value ,of 4.380.53 at 12 months and decreased, thereafter, up to 18 months. 5. In femoral and tibial shaft fractures, the fracture healed uneventfully when uptake ratio of Tc-99m-MDP decreased after 4 months from the day of injury, but the fracture showed delayed union when uptake ratio of Tc-99m-MDP incresed after 4 months from the day of injury. This study suggests that serial measurement of uptake ratio of Tc-99m-NIDP following fractures of femur and tibia with pixel counting method is worthwhile to evaluate and predict for fracture healing.