Comparisons between glucose analogue 2-deoxy-2-(^(18)F)fluoro-D-glucose and ^(18)F-sodium fluoride positron emission tomography/computed tomography in breast cancer patients with bone lesions

AIM: To compare 2-deoxy-2-(^(18)F)fluoro-D-glucose(^(18)FFDG) and ^(18)F-sodium(^(18)F-NaF) positron emission tomography/computed tomography(PET/CT) accuracy in breast cancer patients with clinically/radiologically suspected or known bone metastases.METHODS: A total of 45 consecutive patients with breast cancer and the presence or clinical/biochemical or radiological suspicion of bone metastatic disease underwent ^(18)F-FDG and ^(18)F-fluoride PET/CT. Imaging results were compared with histopathology when available, or clinical and radiological follow-up of at least 1 year. For each technique we calculated: Sensitivity(Se), specificity(Sp), overall accuracy, positive and negative predictive values, error rate, and Youden's index. Mc Nemar's χ~2 test was used to test the difference in sensitivity and specificity between the two diagnostic methods. All analyses were computed on a patient basis, and then on a lesion basis, with consideration ofthe density of independent lesions on the coregistered CT(sclerotic, lytic, mixed, no-lesions) and the divergent site of disease(skull, spine, ribs, extremities, pelvis). The impact of adding ^(18)F-Na F PET/CT to the work-up of patients was also measured in terms of change in their management due to ^(18)F-Na F PET/CT findings. RESULTS: The two imaging methods of ^(18)F-FDG and ^(18)F-fluoride PET/CT were significantly different at the patient-based analysis: Accuracy was 86.7% and 84.4%, respectively(Mc Nemar's χ~2 = 6.23, df = 1, P = 0.01). Overall, 244 bone lesions were detected in our analysis. The overall accuracy of the two methods was significantly different at lesion-based analysis(Mc Nemar's χ~2 = 93.4, df = 1, P < 0.0001). In the lesion density-based and site-based analysis, ^(18)F-FDG PET/CT provided more accurate results in the detection of CT-negative metastasis(P < 0.002) and vertebral localizations(P < 0.002); ^(18)F-Na F PET/CT was more accurate in detecting sclerotic(P < 0.005) and rib lesions(P < 0.04). ^(18)F-Na F PET/CT led to a change of management in 3 of the 45 patients(6.6%) by revealing findings that were not detected at ^(18)F-FDG PET/CT. CONCLUSION: ^(18)F-FDG PET/CT is a reliable imaging tool in the detection of bone metastasis in most cases, with a diagnostic accuracy that is slightly, but significantly, superior to that of ^(18)F-Na F PET/CT in the general population of breast cancer patients. However, the extremely high sensitivity of ^(18)F-fluoride PET/CT can exploit its diagnostic potential in specific clinical settings(i.e., small CT-evident sclerotic lesions, high clinical suspicious of relapse, and negative ^(18)F-FDG PET and conventional imaging).

Correlation between thoracic aorta 18F-natrium fluoride uptake and cardiovascular risk

AIM: To investigating the relationship between thoracic and cardiac 18F-Natrium-Fluoride(18F-Na F) uptake,as a marker of ongoing calcification and cardiovascular risk factors.METHODS: Seventy-eight patients(44 females,mean age 63,range 44-83) underwent whole body 18F-Na F positron emission tomography/computed tomography. Cardiovascular risk(CVR) was used to divide these patients in three categories: Low(LR),medium(MR) and high risk(HR). 18F-Na F uptake was measured by manually drawing volumes of interest on the ascendingaorta,on the aortic arch,on the descending aorta and on the myocardium; average standardized uptake value was normalized for blood-pool,to obtain target-tobackground ratio(TBR). Values from the three aortic segments were then averaged to obtain an index of the whole thoracic aorta.RESULTS: A significant difference in whole thoracic aorta TBR was detected between HR and LR(1.84 ± 0.76 vs 1.07 ± 0.3,P < 0.001),but also between MR and HR-LR(1.4 ± 0.4,P < 0.02 and P < 0.01,respectively). Significance of this TBR stratification strongly varied among thoracic aorta subsegments and the lowest P values were reached in the descending aorta(P < 0.01). Myocardial uptake provided an effective CVR classes stratification(P < 0.001).Correlation between TBR and CVR was appreciable when the whole thoracic aorta was considered(R = 0.67),but it peaked when correlating the descending thoracic segment(R = 0.75),in comparison with the aortic arch and the ascending segment(R = 0.55 and 0.53,respectively). CONCLUSION: Fluoride uptake within the thoracic aorta wall effectively depicts patients' risk class and correlates with cardiovascular risk. Descending aorta is the most effective in CVR determination.