The added value of (99)Tcm-MDP SPECT/CT combined with three-phase bone scintigraphy for differential diagnosis in patients with suspected bone tumor

Objective To investigate the added value of SPECT/CT combined with three-phase bone scintigraphy for differential diagnosis in patients with suspected bone tumor compared with 99Tcm-MDP three-phase bone scintigraphy.Methods Forty-five patients with mean age (44.1 ±21.2) years who were suspected to have bone tumors,underwent 99Tcm-MDP three-phase bone scintigraphy and SPECT/CT between July 2008 and September 2011.They were retrospectively reviewed.All patients had pathological diagnosis based on surgical resection or lesion biopsy.The three-phase bone scintigraphy images were analyzed,and combined SPECT/CT images were then analyzed by two experienced nuclear medicine physicians.The third nuclear medicine physician would be consulted if there was disagreement between these two investigators.Each lesion was diagnosed as either malignant or benign.Compared with the pathology diagnosis,the diagnostic ability of three-phase bone scintigraphy images and SPECT/CT combined with threephase bone scintigraphy were evaluated.The diagnostic accuracy of three-phase bone scintigraphy images and SPECT/CT combined with three-phase bone scintigraphy were calculated,and x2 test was used to compare the difference between them.Results Among these 45 lesions,29 were malignant and 16 benign.Using three-phase bone scintigraphy and SPECT/CT combined with three-phase bone scintigraphy for the differential diagnosis of bone lesions,the sensitivity,specificity,positive predictive value and negative predictive value were 96.6％ (28/29) vs 100％ (29/29),37.5％ (6/16) vs 81.2％ (13/16),73.7％ (28/38) vs 90.6％ (29/32),and 6/7 vs 100％ (13/13),respectively.The diagnostic accuracy of the three-phase bone scintigraphy was 75.6％ (34/45),and up to 93.3％ (42/45) for the combined examination (x2 =4.145,P ＜0.05).Conclusions Compared with three-phase bone scintigraphy alone,the diagnostic accuracy of SPECT/CT combined with three-phase bone scintigraphy is significantly improved.The combination might provide added value over three-phase bone scintigraphy for differential diagnosis in patients with suspected bone tumor. Key words: Bone neoplasms; Radionuclide imaging; Tomography,emission-computed,single-photon; Tomography,X-ray computed; MDP