A Comparison of Accuracy of Planar and Evolution SPECT/CT Bone Imaging in Differentiating Benign from Metastatic Bone...

To compare sensitivity, specificity, accuracy and diagnostic confidence in the differentiation between benign and metastatic bone lesions on whole body planar bone scintigraphy and Evolution SPECT/CT.

Eighty diagnosed or suspected cancer patients with indeterminate lesions on planar scintigraphy were recruited in the present prospective study. Additional whole body Evolution SPECT/CT was performed after whole body planar scintigraphy. All lesions on both imagings were categorized into 5 categories; definitely metastasis, probably metastasis, indeterminate, probably benign and definitely benign. The diagnosis of each lesion was confirmed by follow-up imaging, pathological findings or clinical follow-up for at least 6 months.

Detected lesions on planar scintigraphy and Evolution SPECT/CT imaging were 442 and 477 lesions, respectively.The sensitivity, specificity and accuracy of planar scintigraphy and Evolution SPECT/CT imaging in the diagnosis of metastatic lesions were 27% (95% CI: 13.8, 44.1), 63.2% (95% CI: 58.5, 67.7), 60%, and 97.3% (95% CI: 85.8, 99.9), 100% (95% CI: 96.4, 100) and 99.8%, respectively. Indeterminate lesions on planar scintigraphy were 34.2% (151 lesions from total 442 lesions, which 135 of these 151 indeterminate lesions or 89.4% were located in axial skeleton). Evolution SPECT/CT images were able to characterize all indeterminate lesions.

Differentiation of benign and metastatic lesions by Evolution SPECT/CT images has superior diagnostic performance and diagnostic confidence over the planar scintigraphy. Thus, Evolution SPECT/CT images should be considered in characterization of indeterminate lesions on planar scintigraphy, especially in the axial skeleton.