Quantifying Change in Perfusion after Genicular Artery Embolization with Parametric Analysis of Intraprocedural Digital Subtraction Angiograms

Purpose: To quantify perfusion changes during genicular artery embolization (GAE) with the qualitatively described "pruning" technique using parametric analysis.Materials and methods: A total of 12 patients underwent unilateral GAE with a total of 36 vessels embolized. Among 34 of the 36 vessels embolized, regions of interest (ROIs) were placed on parent vessels (PVs) and hyperemic target vessels (TVs) before and after GAE. For each ROI, peak intensity (PI), time to arrival (TTA), and area under the curve (AUC) were computed and compared between PV and TV. Volume of embolic administered was correlated with adverse events.Results: No change was seen in PI, TTA, and AUC in the PV after GAE. Reduction in AUC (1,495.7 +/- 521.5 vs 1,667.4 +/- 574.0; P << .01) and PI (195.1 +/- 43.8 vs 224.3 +/- 49.2; P << .01) with increase in TTA (3.42 s +/- 1.70 vs 1.92 s +/- 1.45; P << .01) within the TV were observed after GAE. Median follow-up time was 89 days (range, 21-254 days). Reduction in clinical symptoms was also noted based on the Western-Ontario and McMaster Universities Arthritis Index total and pain scale at 1 month (total, 42.9% +/- 23.0; pain, 54.4% +/- 9.8; P << .01) and 3 months (total, 42.5% +/- 14.9; pain, 57.8% +/- 10.6; P << .01). Eight total mild adverse events (minor/self-limiting) were noted per Society of Interventional Radiology guidelines. A larger volume of embolic was observed in knees with skin changes (3.4 mL +/- 0.4 vs 1.7 mL +/- 0.4; P << .001). Furthermore, all skin changes were seen with embolic volumes >3.0 mL.Conclusions: Quantification of intraprocedural perfusion changes with GAE demonstrated reduced flow to the TV with maintained flow in the PV and acceptable clinical outcomes. A potential relationship between embolic volume and nontarget embolization was also highlighted.