Neuroendocrine liver metastases: Vascular patterns on triple-phase MDCT are indicative of primary tumour location

PurposeTo re-evaluate and compare CT features of neuroendocrine liver metastases (NLM) from pancreatic (p) and enteric (e) gastroenteropancreatic (GEP) tumours.Material and methodsFrom 2006-2013, all patients with proven GEP-neuroendocrine tumours (NETs) with at least one NLM, no previous treatment were included. On unenhanced, arterial and portal phases, NLMs were characterized as hypo-, iso- or hyperattenuating in consensus by 2 radiologists blinded to clinical data. Enhancement patterns (EP) corresponded to the combination of arterial/portal CT attenuation.Results78 patients (43 men, 55%, mean 56 ± 13 yo) and 559 NLMs were analyzed. pNLMs were more frequently hypoattenuating on unenhanced CT than eNLMs (72% vs. 57%, p < 0.001). 70% of the lesions were hypervascular with no significant difference between pNLMs and eNLMs (p = 0.32). eNLMs were more frequently hypoattenuating on portal phase than pNLMs (88% vs. 56%, p < 0.001). eNLMs were more frequently hyper/hypo than pNLMs (56% vs. 28%, p < 0.001). pNLMs were more frequently hyper/iso than eNLMs (33% vs. 8%, p < 0.001). Other NLMs showed various patterns, including hypo/hypo in 12%.ConclusionMost NLMs of GEP tumours are hypervascular but the enhancement pattern on multiphasic CT depends on the primary tumour. These differences are helpful when the primary tumour has not been diagnosed.