Prognostic value of incidental hypervascular micronodules detected on cone-beam computed tomography angiography of patients with liver metastasis

Purpose: To determine the clinical relevance of incidentally-found hypervascular micronodules (IHM) on cone-beam computed tomography angiography (CBCTA) in patients with liver metastasis undergoing transarterial (chemo)embolization (TACE/TAE). Material and methods: This was a HIPAA-compliant institutional review board-approved single-institution retrospective review of 95 non-cirrhotic patients (52 men; mean age, 60 years) who underwent CBCTA prior to (chemo)embolic delivery. IHM were defined by the presence of innumerable subcentimetre hepatic parenchymal hypevascular foci not detected on pre-TACE/TAE contrast-enhanced cross-sectional imaging. Multivariate analysis was performed to compare time to tumour progression (TTP) between patients with and without IHM. Results: IHM were present in 21 (22%) patients. Patients with IHM had a significantly shorter intrahepatic TTP determined by a higher frequency of developing new liver metastasis (hazard ratio [HR]: 1.99; 95% confidence interval [CI] 1.08–3.67, P= 0.02). Patients with IHM trended towards a shorter TTP of the tumour(s) treated with TACE/TAE (HR: 1.72; 95% CI: 0.98–3.01, P= 0.056). Extrahepatic TTP was not significantly different between the two cohorts (P= 0.27). Conclusion: Patients with IHM on CBCTA have worse prognosis due to a significantly higher risk of developing new hepatic tumours. Further work is needed to elucidate its underlying mechanisms of pathogenesis. Key Points: • 21% of liver metastasis patients undergoing TACE/TAE have IHM on CBTA. • IHM are associated with a high risk of developing new hepatic tumours. • IHA are also associated with a trend toward poorer response to TACE/TAE.