Opportunistic osteoporosis screening on FDG PET/CT scans in breast carcinoma: a comparison with DXA

Introduction: Reduced bone mineral density is often observed in breast cancer patients. Routine PET/CT scans can be used for detection of low bone mineral density.Aim: To evaluate prevalence of osteopenia, osteoporosis and fracture risk in pre and post-therapy breast carcinoma patients undergoing ۱۸F-FDG PET/CT scans.Materials and methods: In this retrospective study L۱-L۴ vertebral and femoral neck CT mean Hounsfield unit attenuation and their corresponding SUVmax values from initial staging and end of treatment FDG PET/CT scans performed breast carcinoma patients were compared. Post chemo ± hormonal therapy FDG PET/CT HU values were also compared to DXA scan T- scores. Results: Significant increase in prevalence of post chemo ± hormonal therapy osteopenia, osteoporosis and fractures (۶۲%, ۱۸% and ۱۶% vs baseline of ۳۵%, ۴% and ۹% respectively). CECT mean attenuation values of ≤ ۱۷۴.۶ HU and ≤ ۱۱۷.۲ HU for detection of osteopenia and osteoporosis with sensitivity of ۱۰۰% and specificity of ۹۴.۲ % for L۱-L۴ vertebrae, and ≤ ۱۷۶.۸ HU and ≤ ۱۱۷.۸ HU for osteopenia and osteoporosis with sensitivity of ۱۰۰% and specificity ۹۶.۴% at femoral necks respectively were suggested. Furthermore, mean attenuation values of ≤ ۱۲۵.۹ HU with sensitivity and specificity of ~ ۱۰۰% and ۷۹% and ≤ ۱۲۴.۸ HU with sensitivity of ۱۰۰% and specificity ~ ۷۹.۸% were suggested for increased L۱-L۴ vertebral and femoral neck fractures prevalence/ risk respectively. An associated post chemo ± hormonal therapy decline in vertebral and femoral neck mean SUVmax values in range of ۱۴% was also observed.

Keywords:

Breast carcinoma , FDG PET/CT , Hounsfield units , DXA scan , Osteoporosis , fracture risk assessment