Indeterminate solitary vertebral lesions on planar scintigraphy

Summary Objective: This study aims to evaluate the added value of hybrid SPECT-CT in differential diagnosis of indeterminate solitary vertebral lesion (SVL) on planar scintigraphy in patients with non-small cell lung cancer (NSCLC). Methods: Sixty-three NSCLC patients with indeterminate “hot spot” SVL on planar scintigraphy were retrospectively included in this study. Pathological confirmation and followup by whole body scintigraphy and SPECT-CT were used as golden standard for the evaluation of diagnostic performance of planar scintigraphy, SPECT, and SPECT-CT. Receiver operating characteristic (ROC) analyses were performed and compared among the three imaging modalities. For subgroup analysis, the performance of each imaging modality in different NSCLC subgroups including age, gender, histology of primary tumor and nature, site and location of SVL were analyzed, respectively. The impact of SPECT-CT on the management of NSCLC patient with SVL was also analyzed. Results: The sensitivity and specificity of planar scintigraphy, SPECT, and SPECT-CT in differentiating SVL were 41.9 % and 81.2 %, 83.9 % and 71.9 %, and 90.3 % and 90.6 %, respectively. SPECT-CT performed significantly better than both planar scintigraphy (P < 0.0001) and SPECT (P = 0.0027). The sensitivity for planar scintigraphy in nonlytic SVL was significantly higher than in lytic SVL (88.5 % vs. 50.0 %, P = 0.0008). The sensitivity for the planar scintigraphy and SPECT-CT in dorsal SVL was significantly higher than in non-dorsal SVL (55.0 % vs. 18.2 %, P = 0.0029 and 100 % vs. 85.7 %, P = 0.0236, respectively). SPECT-CT had an impact on the clinical management of 52.6 % (20/38) of patients compared to planar scintigraphy and 23.6 % (9/38) of patients compared to SPECT. Conclusion: Compared to planar scintigraphy and SPECT, hybrid SPECT-CT shows excellent performance in differentiating indeterminate SVL in NSCLC patients, the application of which will significantly impact patient management.