REVIEW ARTICLE Biologic Imaging of Head and Neck Cancer: The Present and the Future

SUMMARY: While anatomic imaging (CT and MR imaging) of HNC is focused on diagnosing and/or characterizing the disease, defining its local extent, and evaluating distant spread, accurate assess-ment of the biologic status of the cancer (cellularity, growth rate, response to nonsurgical chemora-diation therapy, and so forth) can be invaluable for prognostication, planning therapy, and follow-up of lesions after therapy. The combination of anatomic and biologic imaging techniques can thus provide a more comprehensive evaluation of the patient. The purpose of this work was to review the present and future clinical applications of advanced biologic imaging techniques in HNC evaluation and management. As part of the biologic imaging array, we discuss MR spectroscopy, diffusion and perfusion MR imaging, CTP, and FDG-PET scanning and conclude with exciting developments that hold promise in assessment of tumor hypoxia and neoangiogenesis. ABBREVIATIONS: ADC apparent diffusion coefficient; BF blood flow; BV blood volume; Cho choline; Cr creatine; CP capillary permeability; CTP CT perfusion; DCE dynamic contrast-enhanced; DTI diffusion tensor imaging; DWI diffusion-weighted MR imaging; 18F fluorine 18; FMISO fluoromisonidazole; FDG-PET fluorodeoxyglucose–positron-emission to-mography; FLT fluorothymidine; GTV gross tumor volume; HNC head and neck cancer