The added clinical value of SPECT/CT in interpretation of indeterminate bone scans findings and establishing more definitive diagnosis of bone pathologies

90 Objectives The aim of this study is to investigate the added value of SPECT/CT in interpretation of indeterminate bone scan findings and to determine the cause of bone pain unexplained with the other imaging techniques. Methods This retrospective study includes 143 consecutive patients who underwent bone SPECT/CT following planar or SPECT bone scintigraphy due to indeterminate bone scan findings or unexplained bone or joint pain. There were two groups of patients: First group was composed of 68 patients who referred for staging of malignant disease and bone scan findings were interpreted as undetermined. The second group included 75 orthopedic patients. Standard three phase or just delayed bone scintigraphy was performed after intravenous injection of 740 MBq 99mTc-MDP. SPECT/CT imaging was performed using GE NM/CT 670 camera. Results We have assessed the additional value of SPECT/CT in 68 malign and 75 orthopedic patients. Equivocal 82 lesions on planar bone scintigraphy in 68 malignant patients were evaluated. According to SPECT/CT findings equivocal lesions were classified as malign (23%), benign (66%) and indeterminate (11%). SPECT/CT was found especially useful in characterizing and localizing spinal lesions and reducing equivocal bone scan readings considerably. In orthopedic group SPECT/CT provided additional information in 60 of 75 (80%) patients and was unhelpful in 15 (20%) patients. A specific diagnosis was made in 30 of 60 (50%) patients. More accurate localization of degenerative changes was observed in the remaining 30 patients. It was found that >50% patients, management was changed after the findings of the SPECT/CT study and many patients did not undergo any further investigation. Conclusions SPECT/CT improved the diagnostic confidence and specificity when compared with conventional bone scintigraphy and reduced the need for other investigations such as repeated radiographs or MRI, thereby saving time, cost and subsequent radiation exposure.