Objective: To determine the best predictor for the response to and survival with transarterial radioembolisation (RE) with (90)yttrium microspheres in patients with liver metastases.
Methods: Forty consecutive patients with liver metastases undergoing RE were evaluated with multiphase CT, perfusion CT and (99m)Tc-MAA SPECT. Arterial perfusion (AP) from perfusion CT, HU values from the arterial (aHU) and portal venous phase (pvHU) CT, and (99m)Tc-MAA uptake ratio of metastases were determined. Morphologic response was evaluated after 4 months and available in 30 patients. One-year survival was calculated with Kaplan-Meier curves.
Results: We found significant differences between responders and non-responders for AP (P < 0.001) and aHU (P = 0.001) of metastases, while no differences were found for pvHU (P = 0.07) and the (99m)Tc-MAA uptake ratio (P = 0.40). AP had a significantly higher specificity than aHU (P = 0.003) for determining responders to RE. Patients with an AP >20 ml/100 ml/min had a significantly (P = 0.01) higher 1-year survival, whereas an aHU value >55 HU did not discriminate survival (P = 0.12). The Cox proportional hazard model revealed AP as the only significant (P = 0.02) independent predictor of survival.
Conclusion: Compared to arterial and portal venous enhancement and the (99m)Tc-MAA uptake ratio of liver metastases, the AP from perfusion CT is the best predictor of morphologic response to and 1-year survival with RE.
Key points: • Perfusion CT allows for calculation of the liver arterial perfusion. • Arterial perfusion of liver metastases differs between responders and non-responders to RE. • Arterial perfusion can be used to select patients responding to RE.