[Post-therapeutic imaging strategies and follow-up in head and neck malignant tumours]

Positron emission tomography-computed tomography versus positron emission tomography-magnetic resonance imaging for diagnosis of oral squamous cell carcinoma: A pilot study

Diagnostic imaging of head and neck cancer has made enormous progress during recent years. Next to morphological imaging modalities (computed tomography [CT] and magnetic resonance imaging [MRI]), there are also hybrid imaging systems that combine functional and morphological information (positron emission tomography [PET]/CT and PET/MRI). The aim of this study was to compare the diagnostic accuracy of PET/MRI in the diagnosis of head and neck cancer with other imaging modalities (MRI, CT, PET/CT). Ten patients (nine male and one female) with histologically proven oral squamous cell carcinoma participated in an 18 F-FDG-PET/CT scan and an additional 18 F-FDG PET/MRI scan prior to surgery. The morphological and functional results were compared with the histological results. Inclusion criteria were histologically proven oral squamous cell carcinoma and no prior surgical intervention, medical therapy, or local external radiation. There was no significant correlation between tumor differentiation and maximum standard uptake values. Functional imaging showed a slightly better correlation with the measurement of the maximal tumor diameter, whereas pure morphological imaging showed a better correlation with the measurement of infiltration depth. Only with PET/MRI could correct lymph node staging be reached; the other imaging tools showed false-negative or false-positive results. In conclusion, we showed in our limited patient cohort that PET/MRI is superior to the morphological imaging modalities, especially for lymph node staging.

Current oncologic concepts and emerging techniques for imaging of head and neck squamous cell cancer

The incidence of head and neck squamous cell carcinoma (HNSCC) is increasing and currently they account for 5% of all malignancies worldwide. Inspite of ongoing developments in diagnostic imaging and new therapeutic options, HNSCC still represents a multidisciplinary challenge.One of the most important prognostic factors in HNSCC is the presence of lymph node metastases. Patients with confirmed nodal involvement have a considerable reduction of their 5-year overall survival rate. In the era of individually optimised surgery, chemotherapy and intensity modulated radiotherapy, the main role of pre- and posttherapeutic imaging remains cancer detection at an early stage and accurate follow-up. The combined effort of early diagnosis and close patient monitoring after surgery and/or radio-chemotherapy influences disease progression and outcome predicition in patients with HNSCC.This review article focuses on currrent oncologic concepts and emerging tools in imaging of head and neck squamous cell cancer. Besides the diagnostic spectrum of the individual imaging modalities, their limitations are also discussed. One main part of this article is dedicated to PET-CT which combines functional and morphological imaging. Furthermore latest developments in MRI are presented with regard to lymph node staging and response prediction. Last but not least, a clinical contribution in this review explains, which information the head and neck surgeon requires from the multimodality imaging and its impact on operation planning.