Role and responsibility of multimodal imaging in head and neck cancer

: Hungary is first in head and neck cancer mortality in Europe in men and also in women. Head and neck (HN) is a difficult region, its anatomy and also pathology is very complex, various connection points exist between the sites which determine the extension of the disease. Diagnostic algorithms as well as imaging techniques have to be optimized to examine in standard manner. Like most other cancers, prognosis depends largely on the stage of the tumor. Accuracy of tumor detection and evaluation is very important because it affects treatment planning. As non-surgical organ-preserving therapeutic modalities (chemotherapy, chemoradiotherapy, targeted biological therapy) gain general acceptance, the importance of noninvasive diagnostic accuracy as well as radiologic evaluation of the extent of the tumor has increased. Clinical examinations including endoscopy should be combined with radiologic imaging to assess the precise local (T), regional nodal (N), and distant (M) extent of the tumor. Computed tomography (CT) and magnetic resonance imaging (MRI) have become basic tools in the diagnosis of head and neck tumors. They are both useful for assessing deep tumor extensions, able to detect changes missed by endoscopy. It has been shown that the primary determined tumor stage increases in up to 90% of patients after the results of cross sectional imaging. MRI is being increasingly used and has become the gold standard in head and neck cancer for staging, assessing tumor response, finding recurrent tumor and also for treatment planning in radiotherapy. The field strength of MRI scanners has been increasing to 1.5 T and now 3 T with better signal-to-noise ratio, higher resolution images and better tissue diagnosis. Functional MR techniques such as dynamic contrast enhanced MRI (DCE-MRI) and diffusion weighted MRI (DW-MRI) may provide further characterization. PET/CT is beneficial in detecting unsuspected metastatic nodes, distant disease and second primary tumor. PET/CT and MRI both appeared almost similarly accurate in the detection of an occult primary tumor. The effective management of patients depends highly on the competece of radiologists and requires close collaboration between clinical and surgical oncologists, diagnostic and therapeutic radiologists as well as pathologists.