Intrahepatic Flow Redistribution in Patients Treated with Radioembolization

In planning Yttrium-90 (Y-90)-radioembolizations, strategy problems arise in tumours with multiple arterial supplies. We aim to demonstrate that tumours can be treated via one main feeding artery achieving flow redistribution by embolizing accessory vessels. One hundred Y-90-radioembolizations were performed on 90 patients using glass microspheres. In 19 lesions/17 patients, accessory branches were found feeding a minor tumour portion and embolized. In all 17 patients, the assessment of the complete perfusion was obtained by angiography and single photon emission computerized tomography-computerized tomography (SPECT-CT). Dosimetry, toxicity, and tumor response rate of the patients treated after flow redistribution were compared with the 83 standard-treated patients. Seventeen lesions in 15 patients with flow redistribution were chosen as target lesions and evaluated according to mRECIST criteria. In all patients, the complete tumor perfusion was assessed immediately before radioembolization by angiography in all patients and after the Y-90-infusion by SPECT-CT in 15 of 17 patients. In the 15 assessable patients, the response rate in their 17 lesions was 3 CR, 8 PR, and 6 SD. Dosimetric and toxicity data, as well tumour response rate, were comparable with the 83 patients with regular vasculature. All embolization procedures were performed successfully with no complications, and the flow redistribution was obtained in all cases. Results in term of toxicity, median dose administered, and radiological response were comparable with standard radioembolizations. Our findings confirmed the intratumoral flow redistribution after embolizing the accessory arteries, which makes it possible to treat the tumour through its single main feeding artery.