PET/CT spinal canal lesions with multimodality imaging correlation illustrate what the interpreting clinician should know about findings within, around, and down through the spinal canal

Learning Objectives 1. Review the imaging features and clinical implications of benign and malignant spinal canal lesions, with emphasis on accurate localization, utilizing multimodality imaging. 2. Present and discuss a range of PET/CT imaging cases, including: pre-treatment and post-treatment neoplastic processes; typical and unusual presentations of primary and metastatic spinal canal lesions.

Cases presented include primary and metastatic diseases, involving various components of the spinal canal anatomy, extending from the craniocervical junction to the sacral canal, including: intramedullary and extramedullary lesions; intradural and epidural lesions; and neural foraminal extension. Benign and malignant etiologies are shown, for example: demyelinating plaques of multiple sclerosis; active degenerative disease; astrocytoma; breast cancer; lung cancer; multiple myeloma/plasmacytoma; and melanoma. Appropriate literature is reviewed. PET/CT imaging is an essential tool in the staging and monitoring of numerous malignancies. PET/CT has well-documented benefits and limitations. Benefits include: co-localization of metabolic activity to a mass lesion; identification of lesions that lack clear mass effect, have infiltrative processes, or have a non-specific appearance on other imaging; and investigation of occult diseases. Limitations include: registration and attenuation correction artifacts; spatial resolution of FDG-PET and decreased soft tissue contrast of associated low dose CT within the spinal canal; and FDG uptake in active arthropathy. Timely recognition and reporting of critical findings is important in regards to spinal canal lesions, since the consequences of delayed treatment can be serious. Cord compression is the most urgent concern, but may be avoidable, if spinal canal invasion is recognized early, and the patient is referred for appropriate therapy