Postoperative and Postradiation Changes on Imaging

Correlation between PET-CT and ct in the staging after the treatment of head and neck squamous cell carcinoma

OBJECTIVE

The aim of this study is to find out if a single imaging test is enough to follow-up on an oncological post-treatment patient. In such a case, we would know which was more valuable after comparing the two, by CT or PET-CT.

METHODS

Between January 2012 and July 2018, we collected data from all patients with previous medical history who were treated with a head and neck squamous cell carcinoma in our hospital, through surgery or by using an organ preservation protocol which we had done. Patients were required to have a CT and a PET-CT performed in a maximum period of 30 days between techniques. We compared the post post-treatment stage given to each case by using only the physical examination (only the CT and the PET-CT), with the ones given by the Tumor Board. After treatment, we analysed the similarity through Cramer's V statistic test.

RESULTS

We performed a comparative analysis, obtaining a correlation of 0.426 between the stages given by the Tumor Board and the one assigned based on physical examination, without imaging techniques. By only using the computed tomography as an imaging method the correlation was 0.565, whereas with only the use of positron emission computed technology, it was estimated at 0.858. When we compared the statistical association between stages using exclusively one of the two imaging techniques, the correlation was 0.451.

CONCLUSION

Independent of the modality, we have demonstrated that in patients who have received previous treatment, there was a higher correlation in the stages with respect to the diagnostic method conducted by the Tumor Board using PET-CT as the sole image.

LEVEL OF EVIDENCE

Level 1.

Advanced CT and MR Imaging of the Posttreatment Head and Neck

Advances in MR and computed tomography (CT) techniques have resulted in greater fidelity in the assessment of treatment response and residual tumor on one hand and the assessment of recurrent head and neck malignancies on the other hand. The advances in MR techniques primarily are related to diffusion and perfusion imaging which rely on the intrinsic architecture of the tissues and organ systems. The techniques exploit the density of the cellular architecture; and the vascularity of benign and malignant lesions which in turn affect the changes in the passage of contrast through the vascular bed. Dual-energy CT and CT perfusion are the major advances in CT techniques that have found significant applications in the assessment of treatment response and tumor recurrence.

Postoperative and postradiation head and neck: role of magnetic resonance imaging

Interpretation of head and neck imaging after treatment for malignancy poses a challenge even for the experienced neuroradiologist. While computed tomography is often the preferred modality for assessment of the head and neck due to its faster acquisition, magnetic resonance imaging (MRI) is superior in the evaluation of nasopharyngeal, sinonasal and skull base tumors. In this article, we review pretherapy imaging protocols, common surgical approaches and reconstructions, postsurgical and postradiation MRI appearance and complications, MRI criteria for tumor recurrence and clinical applications of advanced MRI techniques as applicable to head and neck tumors.