Furthermore, it may help decrease imaging time because the Dixon water-only and fat- only images are acquired simultaneously [41,42]. FDG-PET/CT Area of Interest As a general rule, PET/CT imaging maximum standard uptake value can be useful for differentiating between benign and malignant musculoskeletal masses. When combined with anatomic data provided by CT, FDG-PET/CT can be useful in distinguishing aggressive soft tissue tumors from benign lesions [43-45]. Benz et al [46] showed that FDG-PET can be used to determine a tumor glycolytic phenotype in sarcomas, which correlates significantly with histologic grade. Fused FDG-PET/CT images can be used to plan biopsy, targeting areas with more metabolic activity that may give higher diagnostic yield. Furthermore, a meta-analysis found that FDG-PET can be a helpful tool for predicting outcome in patients with soft tissue sarcoma [47]. Lastly, FDG-PET/CT is an excellent modality to detect metastatic disease and assess treatment response [48]. Despite these benefits, FDG-PET/CT does not usually play a role as the next imaging study for the characterization of a soft tissue mass when initial radiographs or US are nondiagnostic. Image-Guided Biopsy Area of Interest The literature does not support the use of image-guided biopsy as the next step in evaluation following nondiagnostic radiographs or US of a soft tissue mass. At least 20% to 25% of soft tissue masses can demonstrate features that allow for confident diagnosis based on MRI alone [23], many of which are benign and thus would not warrant biopsy. Therefore, diagnostic imaging that includes comprehensive characterization of the mass should routinely be performed before biopsy. In fact, the National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology for Soft Tissue Sarcoma state that biopsy should be performed only after adequate imaging [24].
Soft Tissue Masses. Furthermore, it may help decrease imaging time because the Dixon water-only and fat- only images are acquired simultaneously [41,42]. FDG-PET/CT Area of Interest As a general rule, PET/CT imaging maximum standard uptake value can be useful for differentiating between benign and malignant musculoskeletal masses. When combined with anatomic data provided by CT, FDG-PET/CT can be useful in distinguishing aggressive soft tissue tumors from benign lesions [43-45]. Benz et al [46] showed that FDG-PET can be used to determine a tumor glycolytic phenotype in sarcomas, which correlates significantly with histologic grade. Fused FDG-PET/CT images can be used to plan biopsy, targeting areas with more metabolic activity that may give higher diagnostic yield. Furthermore, a meta-analysis found that FDG-PET can be a helpful tool for predicting outcome in patients with soft tissue sarcoma [47]. Lastly, FDG-PET/CT is an excellent modality to detect metastatic disease and assess treatment response [48]. Despite these benefits, FDG-PET/CT does not usually play a role as the next imaging study for the characterization of a soft tissue mass when initial radiographs or US are nondiagnostic. Image-Guided Biopsy Area of Interest The literature does not support the use of image-guided biopsy as the next step in evaluation following nondiagnostic radiographs or US of a soft tissue mass. At least 20% to 25% of soft tissue masses can demonstrate features that allow for confident diagnosis based on MRI alone [23], many of which are benign and thus would not warrant biopsy. Therefore, diagnostic imaging that includes comprehensive characterization of the mass should routinely be performed before biopsy. In fact, the National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology for Soft Tissue Sarcoma state that biopsy should be performed only after adequate imaging [24].