A Retrospective Analysis of the Most Common Bone Metastases of Various Malignant Tumors with Cross-sectional Imaging and 18-FDG-PET/CT Data

Abstract

Objective:To evaluate bone metastases quantitatively and qualitatively with cross-sectional imaging and fluor-18 fluorodeoxyglucose-positron emission tomography (18-FDG-PET) computed tomograph (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 magnetic resonance imaging (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 with regard 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 on T1 sequences whereas 96.4% of them presented hypointensity on T2 and hyperintensity on short tau inversion recovery (STIR) sequences. STIR images were found to be valuable to detect metastases. 18-FDG-PET/CT metabolic tumor volume values showed statistically significant difference with regard to the metastatic tumor types. There was not a statistically significant difference between 18-FDG-PET/CT parameters of lytic and sclerotic metastases.Conclusion: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 correlate 18-FDG-PET/CT parameters for breast and SUVmax values for lung cancers. Metabolic tumor volume values differ with the primary tumor histopathology and are also defined to be a promising prognostic factor in the future.

Keywords

• 18-fdg-pet/ct
• bone metastases
• ct
• mri