Table 3.

Expert opinion on the role of different imaging modalities in the diagnosis and follow-up of patients with gastro-entero-pancreatic neuroendocrine tumours

CT	MRI	US
Mandatory for diagnosis [39], including recurrences, so use if recurrence suspected	During diagnosis, use DWI and liver-specific contrast media for better study of the liver [37, 38]	Can be used at any stage. The use of US contrast medium does not carry any risks, so can be used repeatedly during long-term follow-up [40]
Dynamic CT scanning should be used after contrast medium injection; quadriphasic acquisition should be used for imaging the liver	During prolonged follow-up, MRI may be used in order to reduce the use of CT and risks associated with ionising radiation and the use of contrast agents
During follow-up, can be progressively replaced by other techniques without ionising radiation (MRI, US)

CT computed tomography, DWI diffusion-weighted imaging, MRI magnetic resonance imaging, US ultrasound