肝内動脈塞栓療法におけるマイクロカプセル分布に対する注入テクニックの影響：逐次分岐 in vitro モデルを用いた検討

This study aimed to experimentally investigate how injection technique affects the distribution of microspheres during transarterial radioembolization in a successively bifurcating in vitro model.

A symmetrical phantom, bifurcating 3 times into 8 outlets, was incorporated into a flow circuit. A blood-mimicking fluid was pumped through the phantom using a physiological representative waveform. A microcatheter was placed into the lumen of the phantom, and holmium-165 microspheres were administered with a conventional administration device and a newly designed controlled administration device, containing a rotating syringe to keep the microspheres in suspension during administration. Two clinicians performed manual injections to establish clinically relevant injection rates. Then, different injection profiles were tested using syringe pumps: pulsed vs continuous injections (24 mL/min), and reduced continuous injection rates (10 and 5 mL/min). Microspheres were collected at each outlet and their distribution over the 8 outlets was analyzed.

Continuous high injection rates led to more homogeneous radial distributions of microspheres over the right side of the phantom (outlet 5-8 received 16.5%-23.1% of the microspheres per outlet) compared with the clinically standard used pulsed injections (outlet 5-8 received 11.3%-40.1% of the microspheres per outlet). In contrast, reduced continuous injection rates led to more selective distributions (outlet 5-8 received 2.5%-68.8% of the microspheres at 10 mL/min and 1.0%-80.0% at 5 mL/min).

Injection technique strongly influences the distribution of microspheres. During high continuous injections, more mixing between microspheres and blood-mimicking fluid was observed. This led to more uniform radial microsphere distributions, creating a more predictive setting for transarterial radioembolization.