Usefulness of Integrated PET/MRI in Oropharyngeal Squamous Cell Carcinoma Evaluation

In this three-year prospective project, a total of 160 patients with histologically proven oropharyngeal SCC subjected to chemoradiation will be enrolled. Exclusion criteria include previous head or neck malignant tumor, a second malignant tumor, distant metastasis, contraindications to MRI (renal insufficiency, cochlear implant, cardiac pacemaker, or intracranial aneurysmal ferromagnetic clips), and serum glucose level >200 mg/dl. Each enrolled patients will undergo detail clinical examination, including human papillomavirus test. The participants will undergo low dose chest CT on the same day before PET/MRI. In the posttreatment period, baseline whole body MRI will be obtained 3 months after chemoradiation. Thereafter, the participants will then be followed up also with alternative extend-field CT and whole body MRI by every 6 months. If tumor recurrenceis confirmed or highly suspected, PET/MRI will also be performed for tumor re-staging.

The three-years planning Adequate cases number and follow-up duration are essential for statistical analysis and outcome determination of oropharyngeal SCC treated with chemoradiation. The investigators plan to accomplish this study in 3 years.

In the first year, the works of the this project in the first year will design the data bank categories, set up the workflow and optimize the imaging protocols, determine the diagnostic capability of MRI component, PET component, integrated PET/MRI in tumor staging, determinate any added diagnostic value of noncontrast chest CT in integrated PET/MRI, and study the early treatment response and the patterns of residual tumor.

In the second year, the investigators will continue to the first-year works, and further include the following works to determinate incidence and predictors of treatment failure of oropharyngeal SCC, and to study the patterns of treatment response and early recurrence. In the third year, the investigators will continue to do previous work and will also get sufficient sample size to perform statistical analysis of the relationship between the imaging parameters and patient outcomes, attain comprehensive imaging about patterns of tumor recurrence and posttreatment changes/complications, investigate to what extent biologic imaging parameters may affect outcome and patient selection for chemoradiation, and analysis the accuracy, pitfalls and cost effectiveness of the PET/MRI alone and PET/MRI with noncontrast chest CT in evaluating in patients with oropharyngeal SCC.

PET/MRI data will be acquired on the integrated PET/MRI scanner , which acquires simultaneous PET and MR data with a 3.0-T magnet. The examination protocol will combined a whole-body scan with a dedicated examination of the head and neck area. All participants will fast for 6 h before the scan. At 50-70 min post injection of 370 MBq of FDG, the patient will be placed on the PET/MRI scanner bed. After fast-view T1-weighted MR localizer sequence for scout imaging and Dixon VIBE sequence for attenuation correction, a whole-body PET scan will be performed in 5 bed positions to cover from the head to the proximal thigh, with an acquisition time of 4 min per bed position. Simultaneously, whole body MR image acquisition will be performed for the corresponding 5 bed positions with the axial HASTE sequence and coronal STIR sequence as well as the sagittal T1-weighted Turbo spine echo(TSE) and STIR sequence.