Assessment of particulate embolic agent distribution comparing two delivery techniques in a porcine model

To compare continuous vs pulsed transarterial embolization techniques with microCT and determine their impact on distal vascular penetration.

Transarterial embolization was performed in 7 swine using 75-100-micron microspheres. In each subject, 1 kidney was embolized using continuous injection and contralateral with a pulsed injection technique. Histological analysis validated MicroCT findings (50-100 pixels, postprocedural quantification) in 2 subjects (4 kidneys), after which MicroCT alone was used for outcome assessments.

MicroCT imaging demonstrated similar outcomes to histology. Larger number of particles delivered with continuous vs pulsed technique (6806 vs 6174 particles into 223 ml vs 168 ml renal volume respectively). Percentage of the embolized renal cortex at 50 pixels was 1.1% for the continuous technique (0.1 - 2.3%) vs 0.7% pulsed (0.5 - 1.1%) (p = 0.3). Embolized renal cortex at 100 pixels was 2.9% continuous (1.3 - 4.2%) vs 2.3% pulsed (1.3 - 3.2%) (p = 0.3). Average kidney volume in both groups was 78.1 ml (r, 49-138) and 81 ml (r, 46-111), respectively. A slightly larger amount of embolic was delivered using the continuous vs pulsed: 14 ml (r, 12-20) vs 13.1 ml (r, 8-22). Mean embolic/kidney volume ratio was 0.20 for continuous vs 0.16 for pulsed (25% difference, p = 0.2).

Continuous embolization technique resulted in a larger absolute concentration of embolic particles within the distal renal cortex and overall volume compared to the pulsed technique, though the difference was not statistically significant. Our findings suggest embolic delivery technique for particle embolics may influence amount and efficacy of distal embolization.