State-of-the-art imaging in oesophago-gastric cancer

Abstract

Radiological investigations are essential in the management of oesophageal and gastro-oesophageal junction cancers. The current multimodal combination of CT, 18F-fluorodeoxyglucose positron emission tomography combined with CT (PET/CT) and endoscopic ultrasound (EUS) has limitations, which hinders the prognostic and predictive information that can be used to guide optimum treatment decisions. Therefore, the development of improved imaging techniques is vital to improve patient management. This review describes the current evidence for state-of-the-art imaging techniques in oesophago-gastric cancer including high resolution MRI, diffusion-weighted MRI, dynamic contrast-enhanced MRI, whole-body MRI, perfusion CT, novel PET tracers, and integrated PET/MRI. These novel imaging techniques may help clinicians improve the diagnosis, staging, treatment planning, and response assessment of oesophago-gastric cancer.

Figure 1.

Typical radiological staging pathway for most patients diagnosed with oesophago-gastric cancer in the United Kingdom. EUS, endoscopic ultrasound; PET, positron emission tomography.

Figure 2.

Axial CT showing mural thickening of the distal oesophagus (a), axial fused ¹⁸F-FDG PET/CT (b) showing FDG uptake in the tumour. Clinical staging of both CT and PET/CT was cT3 N0 M0. Endoscopic ultrasound (c) showed that the distal oesophageal tumour (arrow) involved the diaphragmatic crus distally and there was a malignant perioesophageal lymph node (arrowhead), therefore the final staging was cT4a N1 M0 (Images courtesy of Dr K G Foley, Velindre Cancer Centre). FDG, fluorodeoxyglucose; PET, positron emission tomography.

Figure 3.

Small field-of-view axial T ₂ weighted MRI. There is a primary tumour centred on the left-side of the oesophagus extending through the muscularis into the perioesophageal fat (arrow). The normal intact layers of the oesophageal wall are seen on the contralateral side (Image courtesy of Dr A M Riddell, Royal Marsden Hospital).

Figure 4.

Axial fused ¹⁸F-FDG PET/MRI image showing FDG uptake in the primary tumour, locoregional nodes and liver metastasis in a patient with Stage IV oesophago-gastric cancer (Images courtesy of Professors G Cook and V Goh, St. Thomas’ Hospital). FDG, fluorodeoxyglucose.

Figure 5.

CT-based radiotherapy planning image of a distal oesophageal tumour demonstrating the GTV (red), CTV (pink) and PTV (blue) with several isodose lines contoured by clinical oncologists during target volume delineation (Images courtesy of Dr Owen Nicholas, South West Wales Cancer Centre). CTV, clinical target volume; GTV, gross tumour volume; PTV, planning target volume.

Figure 6.

Axial fat-saturated T ₁ weighted MRI performed before (a), 30 s (b), 70 s (c) and 120 s (d) after contrast administration in a patient with a distal oesophageal tumour (arrows). Contrast-enhancement curve showing a type-3 washout curve (e). Focussed K^trans map showing mean K^trans value of 0.39 min⁻¹ within the oesophageal tumour (arrow) (f). (Images courtesy of Professor V Goh, St. Thomas’ Hospital).

Figure 7.

Axial T ₂ weighted MRI, B900 diffusion-weighted MRI, and apparent diffusion coefficient map before (a, b, c) and after (d, e, f) neoadjuvant chemoradiotherapy. The tumour is at the gastro-oesophageal junction, above a moderate-sized hiatus hernia. The tumour decreased in bulk, and mean tumour apparent diffusion coefficient increased from 800 × 10⁻³ mm²/s to 1850 × 10⁻³ mm²/s (Images courtesy of Professor V Goh, St. Thomas’ Hospital).