Objective: To evaluate bone metastases quantitative and qualitatively with cross-sectional imaging and 18-FDG-PET CT data.
Method: To obtain study data, the archive of the Nuclear medicine of our institute was retrospectively searched for the period from January 2015 to December 2018. For MRI evaluation, the signal intensity ratio of involved tissue to normal adjacent tissue was chosen. For CT evaluation, metastases were labelled to be lytic or sclerotic regards to the mean density values. Finally, the maximum and the mean standardized uptake values and metabolic tumor volume values were evaluated quantitatively.
Results: All bone metastases presented hypointensity at T1 sequences whereas % 96.4 of them presented hypointensity at T2 and hyperintensity at STIR sequences. STIR images found to be valuable to detect metastases. 18-FDG-PET CT metabolic tumor volume values showed statistically significant difference regards to the metastatic tumor types. There was not a statistically significant difference between 18-FDG-PET CT parameters of lytic and sclerotic metastases.
Conclusions: We recommend performing STIR images in routine protocol being performed for other reasons such as disc pathologies to detect incidental bone metastases. MRI signal intensity and SUV values cannot be used to predict the tumor histopathology. Sclerotic or lytic appearance does not affect18-FDG-PET CT parameters for breast and SUV max values for lung cancers. MTV values differ with the primary tumor histopathology also defined to be a promising prognostic factor in several recent articles.
Key words: CT, MRI, 18-FDG-PET CT, Bone metastases
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