Perfusion CT best predicts outcome after radioembolization of liver metastases: a comparison of radionuclide and CT imaging techniques

Objective: To determine the best predictor for the response to and survival with transarterial radioembolisation (RE) with 90yttrium microspheres in patients with liver metastases. Methods: Forty consecutive patients with liver metastases undergoing RE were evaluated with multiphase CT, perfusion CT and 99mTc-MAA SPECT. Arterial perfusion (AP) from perfusion CT, HU values from the arterial (aHU) and portal venous phase (pvHU) CT, and 99mTc-MAA uptake ratio of metastases were determined. Morphologic response was evaluated after 4months 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 20ml/100ml/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 99mTc-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