Diagnostic Imaging and Image-Guided Therapy of Skeletal Metastases

Background: The high incidence of skeletal metastases in cancer patients warrants careful detection with imaging and follow-up. Efforts are needed to manage pain associated with skeletal metastases as part of overall patient management. Methods: This article reviews the current methods of diagnostic imaging in the evaluation of skeletal metastases and image-guided treatment of bone metastases for the palliation of pain based primarily on the assessment of imaging and interventional radiologic literature. Results: Approaches to diagnostic imaging of skeletal metastases are summarized. Skeletal scintigraphy provides high sensitivity for detecting skeletal metastases, but targeted computed tomography (CT) or magnetic resonance imaging (MRI) may be needed to increase specificity. Newer imaging modalities, such as positron emission tomography (PET)/CT, improve detection of both lytic and blastic metastases. Minimally invasive percutaneous ablative treatment techniques, including radiofrequency ablation, microwave ablation, and cryoablation, are examined. They provide alternative approaches to radiation therapy to effectively palliate pain of bone metastases. Preliminary results of MR-guided focused ultrasound surgery (MRgFUS) demonstrate its effectiveness in palliating pain from skeletal metastases. Conclusions: Skeletal scintigraphy is the most common imaging modality for detecting skeletal metastases. Additional imaging may be required based on the type of tumor, the disease state, or treatment options. External-beam radiation therapy remains the mainstay for palliation of pain from bone metastases. Alternative minimally invasive and noninvasive image-guided treatment options can provide effective pain palliation.