Anatomic and functional imaging in the diagnosis of spine metastases and response assessment after spine radiosurgery

Abstract

<jats:p>Spine stereotactic radiosurgery (SSRS) has recently emerged as an increasingly effective treatment for spinal metastases. Studies performed over the past decade have examined the role of imaging in the diagnosis of metastases, as well as treatment response following SSRS. In this paper, the authors describe and review the utility of several imaging modalities in the diagnosis of spinal metastases and monitoring of their response to SSRS. Specifically, we review the role of CT, MRI, and positron emission tomography (PET) in their ability to differentiate between osteoblastic and osteolytic lesions, delineation of initial bony pathology, detection of treatment-related changes in bone density and vertebral compression fracture after SSRS, and tumor response to therapy. Validated consensus guidelines defining the imaging approach to SSRS are needed to standardize the diagnosis and treatment response assessment after SSRS. Future directions of spinal imaging, including advances in targeted tumor-specific molecular imaging markers demonstrate early promise for advancing the role of imaging in SSRS.</jats:p>

Bone metastases from differentiated thyroid carcinoma: current knowledge and open issues

“…The diagnostic accuracy proved to be significantly superior to 16/64-row-slice multidetector CT [20]. Furthermore, in case of vertebral metastases, MRI is essential for the assessment of epidural, nerve, and spinal cord involvement, playing a pivotal role in the pre-surgical workup [21,22]. Whole-body (WB) MRI with diffusionweighted imaging (MRI-DWI) is a promising imaging technique in the evaluation of BM from different solid tumours, including DTC [23].…”

Imaging response assessment following stereotactic body radiotherapy for solid tumour metastases of the spine: Current challenges and future directions

“…Conventional MRI is the main imaging modality used in both diagnosis and response assessment after spine SBRT 48 . For diagnosis, MRI has excellent accuracy in assessing bone marrow with respect to metastatic lesions compared with CT (98.7% vs. 88.8%) 49 .…”

“…There was no statistically significant difference in DCE findings between the 1‐hour post‐treatment scan and the 1st follow‐up assessment. There are some limitations inherent to DCE‐MRI including limited field of view, institutional variability in perfusion protocols, longer scanning times, risk of contrast allergy for the patient and cost 48,56 . In addition, these studies are limited by small sample size and retrospective nature and so, although promising, the use of DCE‐MRI in early response assessment remains largely investigational and is not widely available as part of standard imaging post‐SBRT 55 .…”

“…Bone scan imaging with conventional diphosphonates allows whole body assessment, but does not image the tumour itself. Instead, the bone turnover, which is a response to malignant infiltration, is imaged, and this is subject to many confounding reactions including enhanced uptake as a result of bone remodelling after treatment (including radiotherapy), enhanced uptake in the setting of haematopoetic growth factors and altered uptake with concomitant bisphosphonate use 48 . Scan quality is also strongly impacted by the patient’s renal function and metabolic status 62 .…”

Changes in Volume and Density Parameters Measured on Computed Tomography Images Following Stereotactic Body Radiation Therapy of Nonspine Bone Metastases

“…Other promising modalities such as magnetic resonance imaging and nuclear imaging-based biomarkers may also serve as useful adjuncts. 20 However, a significant advantage of using CT-based markers only is that these tests are routinely performed as restaging investigations in metastatic cancer, limiting other follow-up tests is a cost effective strategy that places minimal burden on patients with advanced cancer.…”