Digital tomography for detection of acute occult scaphoid fractures

Diagnosis of occult scaphoid fractures remains a challenge. Traditional management consisting of 2 weeks of immobilization and repeat radiographs results in unnecessary immobilization of many patients without fracture. Magnetic resonance imaging (MRI) is sensitive but expensive. Digital tomography (DT) is an imaging technique that provides fine-cut visualization with minimal radiation exposure and may be used when there is high clinical suspicion despite negative findings on initial radiographs. The authors compared the ability of DT vs MRI to detect acute occult scaphoid fractures. This was an institutional review board-approved, prospective series. Adults for which clinical suspicion for acute scaphoid fracture (presenting within 96 hours of trauma) and negative findings on initial radiographs existed were included. Both a wrist tomogram and MRI were obtained. Wrists were immobilized and reevaluated at 10 to 14 days with repeat radiographs as a control. Studies were interpreted by a radiologist in a blinded fashion. Forty consecutive extremities in 39 patients met the inclusion criteria. Six (15%) of the 40 scaphoids were determined to be fractured on repeat radiographs. Digital tomogram yielded positive findings in 4 of these. Magnetic resonance imaging yielded positive findings in 8 (20%) of the 40 extremities. Sensitivities were 67% and 100% for digital tomogram and MRI, respectively (P=.0001). The positive predictive value was 100% for DT and MRI. The authors found that DT detects more occult scaphoid fractures than initial standard radiographs but is less sensitive than MRI. This is the first study to compare DT with MRI. Digital tomography can be used to augment radiographs and may increase diagnostic efficiency, minimize unnecessary immobilization, and reduce health care costs.