F-FDG-PET/MRI in preoperative staging of oesophageal and gastroesophageal junctional cancer.

AIM

To evaluate integrated 2-[F]-fluoro-2-deoxy-d-glucose (F-FDG) positron-emission tomography (PET)/magnetic resonance imaging (MRI), in comparison with the standard technique, integrated F-FDG-PET/computed tomography (CT), in preoperative staging of oesophageal or gastroesophageal junctional cancer.

MATERIALS AND METHODS

In the preoperative staging of 16 patients with oesophageal or gastroesophageal junctional cancer, F-FDG-PET/MRI was performed immediately following the clinically indicated F-FDG-PET/CT. MRI-sequences included T1-weighted fat-water separation (Dixon's technique), T2-weighted, diffusion-weighted imaging (DWI), and gadolinium contrast-enhanced T1-weighted three-dimensional (3D) imaging. PET was performed with F-FDG. Two separate teams of radiologists conducted structured blinded readings of F-FDG-PET/MRI or F-FDG-PET/CT, which were then compared regarding tumour measurements and characteristics as well as assessment of inter-rater agreement (Cohen's kappa) for the clinical tumour, nodal and metastatic (TNM) stage.

RESULTS

There were no medical complications. Comparison of tumour measurements revealed high correlations without significant differences between modalities. The maximum standardised uptake value (SUV) values of the primary tumour with F-FDG-PET/MRI had excellent correlation to those of F-FDG-PET/CT (0.912, Spearman's rho). Inter-rater agreement between the techniques regarding T-stage was only fair (Cohen's kappa, 0.333), arguably owing to relative over-classification of the T-stage using F-FDG-PET/CT. Agreements in the assessment of N- and M-stage were substantial (Cohen's kappa, 0.849 and 0.871 respectively).

CONCLUSION

Preoperative staging with F-FDG-PET/MRI is safe and promising with the potential to enhance tissue resolution in the area of interest. F-FDG-PET/MRI and F-FDG-PET/CT correlated well for most of the measured values and discrepancies were seen mainly in the assessment of the T-stage. These results facilitate further studies investigating the role of F-FDG-PET/MRI in, e.g., predicting or determining the response to neoadjuvant therapy.