The contribution of bone SPECT to the diagnosis of bone metastases in an African population

Full text: Introduction: A number of studies have demonstrated the value of performing spinal SPECT in addition to planar scintigraphy for the diagnosis of bone metastases. This has however not been demonstrated in an African population where patients frequently present with more advanced disease. The aim of this study was to investigate the contribution of spinal SPECT to the diagnosis of bone metastases in an African population. Materials and methods: In a retrospective study of 576 patients with known primary tumours who underwent skeletal scintigraphy for the diagnosis of bone metastases, the students of 119 patients who underwent planar imaging and SPECT were reviewed. Blinded to the SPECT study, the planar studies were graded for the probability of metastatic disease using a four-point scale, and the number of spinal lesions was noted. This was repeated with the planar and SPECT studies reviewed together. The interpretation using the planar images alone was compared with that obtained after the addition of SPECT using non-parametric tests. Results: Of the 576 patients, 119 (45 men and 74 women) underwent planar and SPECT imaging. A wide variety of primary malignancies were presented but the majority consisted of breast carcinoma (n=55) and prostate carcinoma (n=29). The addition of SPECT resulted in a significant change in the interpretation of these studies (p<0.05), with a significantly lower proportion of patients having equivocal gradings (p<0.01). However the actual number of patients affected was relatively small (n=35) representing about 6% of the total of 576 patients. The addition of SPECT also resulted in the detection of significantly more spinal lesions (p<0.01 ). Conclusion: The addition of SPECT resulted in a statistically significant change in the interpretation of the studies, demonstrating the value of spinal SPECT in this population. However compared to the total patient population the actual number of patients affected was relatively small. In a setting where SPECT cameras are not easily available, planar imaging alone is still adequate in the vast majority of cases. (author)