Diagnostic performance of dual-phase prone ¹⁸F-FDG PET/dynamic contrast-enhanced CT for breast cancer: Comparison with breast MRI and PET/MRI fusion imaging

Objectives To determine the additional value of dual-phase PET and dynamic contrast-enhanced (DCE) CT on prone ¹⁸F-FDG PET/CT examination for assessment of breast lesions by comparison with breast MRI and retrospectively fused PET/MR imaging.

Methods Nineteen consecutive patients with suspected breast cancer underwent prone PET/CT and DCE-MRI within one week. All the patients underwent prone PET/CT of the chest using fixation device similar to breast MR-coil after supine whole-body scan. DCE-CT was performed after first-phase of prone PET/CT, after which second-phase prone PET/CT was performed. Non-contrast prone PET/CT (prPET/pCT), that with second-phase prone PET/CT (dual-prPET/pCT), DCE prone PET/CT (prPET/ceCT), that with second-phase PET/CT (dual-prPET/ceCT), MRI and PET/MRI were assessed separately by using a 5-point scoring system for breast lesions by two experienced physicians. To assess the diagnostic performance among methods, diagnostic capabilities were compared by the ROC analysis followed by the McNemar’s test, based on the reference standard determined by pathological and radiological results.

Results 89 lesions in 19 patients were detected, and determined by the reference standard. The area under the curve and sensitivity of prPET/ceCT (0.94, 88.9%), dual-prPET/ceCT (0.94, 88.9%), MRI (0.95, 88.9%) and PET/MRI (0.99, 88.9%) were significantly higher than prPET/pCT (0.83, 66.7%) and dual-prPET/pCT (0.83, 66.7%) (p<0.01). Specificity of MRI (84.9%) was significantly lower than any of the prone PET/CT (98.1%) and PET/MRI (98.1%) (p<0.05).

Conclusions Prone PET/CT with dynamic contrast-enhanced CT yields significantly higher diagnostic capability than non-contrast prone PET/CT with and without dual-phase PET for breast lesions. MRI/PET fusion shows significantly higher sensitivity than non-contrast PET/CT and higher specificity than MRI