16-Detector multislice CT in the detection of stress fractures: a comparison with skeletal scintigraphy

AIMS: To test the hypothesis that the improved resolution afforded by 16-detector computed tomography (CT) would translate to better stress fracture detection when compared with skeletal scintigraphy. MATERIALS AND METHODS: Thirty-three cases of suspected stress fractures in 26 patients were investigated using skeletal scintigraphy and 16-detector CT performed on the same day. Planar images of the tower limbs were taken 3 h post-injection of 400 MBq Tc-99m-methytene diphosphonate (Tc-99m-MDP). Tc-99m-MDP uptake was quantified at suspected fracture sites. CT was performed using a 16-detector multisection machine employing 0.75 mm detectors and images reconstructed in 0.5 mm increments. Examinations were reported independently and discordant results were compared at follow-up. RESULTS: At initial reporting scintigraphy identified fractures in 13 of the 33 cases and CT identified four of the 33. In one case, on review of the CT images, a fracture was present in the distal fibula that was not initially identified. This resulted in eight scintigraphic-positive CT-negative discordant cases. The Tc-99m-MDP uptake was significantly lower in the discordant fracture group compared with the concordant group (p < 0.01). CONCLUSIONS: Despite technological advances in CT, scintigraphy appeared to detect more stress fractures. As such, multidetector CT should not be used as a routine initial investigation in stress fracture detection. The potential use of Tc-99m-MDP quantification at fracture sites is of interest and may be worth further investigation. (c) 2005 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.