Diagnostic Imaging and Image-Guided Therapy of Skeletal Metastases

Abstract

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.

Imaging of bone metastasis: An update

“…Thus, osseous metastases can be osteoblastic (bone forming) or osteolytic (bone destructive), however, a combination of both processes occurs in most cancers [4] . Osseus metastases from kidney, thyroid and lung maligancies are predominantly osteolytic, while osteoblastic lesions are usually seen in prostate cancer and breast cancer [7] . Furthermore, osteolytic metastases tend to be aggressive, whereas sclerotic metastases typically demonstrate slower progression.…”

“…Less frequent metastatic sites include the mandible, patella, and dital extremities. In the majority of instances, metastases in the appendicular skeleton are secondary to lung cancer and are typically located in the scaphoid, lunate or phalanges [7] ( Figure 1). …”

“…Commensurate with the increased prevalence of bone metastasis, there is potential for significant comorbidities such as pain, limited mobility, hypercalcaemia, spinal cord or nerve root compression, myelosuppression and pathologic fracture [2,6] . Therefore, early detection of skeletal metastasis is critical for (1) accurate staging and optimal treatment; and (2) to allow the implementation of treatment strategies such as surgical fixation, radiotherapy, or bisphosphonate therapy to reduce the risk of complications and improve quality of life [7,8] . This paper briefly reviews our current understanding of the biological mechanisms through which tumours metastasise to bone and describes the available imaging methods to diagnose bone metastasis and monitor response to treatment.…”

18F-FDG-PET/MR increases diagnostic confidence in detection of bone metastases compared with 18F-FDG-PET/CT

“…The significant increase in lesions conspicuity on MR imaging was mainly because of 21 18 F-FDG-positive bone lesions not visible on CT imaging. These lesions likely represent bone marrow infiltration that have not yet resulted in considerable change in bone density but already changed signal in MR imaging [1]. Interestingly, the mean size of these lesions was quite substantial (19.5 mm).…”

“…Multiple imaging techniques are currently available for the detection of the metastatic bone disease including bone scintigraphy, CT, MR and PET/CT imaging [1,2]. Recently, PET/MR hybrid imaging was introduced as a promising tool in oncological imaging research [3].…”