Diagnostic utility of a computer-aided diagnosis system for whole-body bone scintigraphy to detect bone metastasis in breast cancer patients

To compare the diagnostic ability of planar images (PI) and images obtained by a computer-aided diagnosis (CAD) system (Viewer for Standardized Bone Scintigraphies; VSBONE) of whole-body bone scintigraphy for detecting bone metastases in breast cancer patients. 81 women (median: 56 years; range: 32-79) with a history of breast cancer were included in this study. They underwent whole-body bone scintigraphy after intravenous injection of 740 MBq technetium-99m hydroxymethylene diphosphonate. A total of 1066 bones (162 regions of the skull, 657 regions of the spine and pelvis, 223 regions of the sternum and rib, 18 regions of the upper extremities, and 6 regions of the lower extremities) were analyzed. The PI alone, VSBONE images alone, and both PI and VSBONE images (PI + VSBONE) were interpreted independently by two radiologists to diagnose bone metastases, which were then confirmed by magnetic resonance imaging. The sensitivity and specificity for each modality were analyzed using Fisher's exact and McNemar tests. Inter-reviewer agreement was evaluated using a kappa statistic. Bone metastases were confirmed in 43 patients with 442 positive lesions. The average sensitivity of PI, VSBONE images, and PI + VSBONE images was 40.8, 50.2, and 61.8 %, respectively. The average specificity was 97.8, 97.5, and 97.6 %, respectively. The kappa scores were 0.62 for PI, 0.69 for VSBONE, and 0.77 for PI + VSBONE. VSBONE was superior to PI in regard to sensitivity for detecting bone metastases in breast cancer patients. However, an improved CAD system is required to decrease the number of false-negative results.