Embolization is an important and widely utilized technique in interventional radiology. There are a variety of different categories and individual products which can be utilized to perform embolization. Understanding the different classes of embolic agents, the important features of each of these classes including strengths and limitations, and the variation in individual products within the classes is critical for interventional radiologist to practice safely and effectively. This article reviews the different kinds of embolics and relays some of the pertinent physical and chemical properties of individual products which should be considered when determining which embolic to select for a given purpose.

Background: The purpose of this study is to determine and compare the ability of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), aspartate-aminotransferase-to-lymphocyte ratio (ALRI), systemic-inflammation index (SII) and lymphocyte count to predict oncologic outcomes in hepatocellular carcinoma (HCC) patients undergoing transarterial chemoembolization (TACE). Materials and Methods: A single-center retrospective review of 296 patients who were treated for 457 HCCs was performed. Pre- and post-treatment laboratory and treatment outcome variables were collected. Objective radiologic response (ORR), progression-free survival (PFS), and overall survival (OS) were evaluated. Patients were categorized into above and below median scores and compared. Results: The median pretreatment NLR, PLR, ALRI, SII, and lymphocyte count were 2.7 (range: 0.4– 55), 88.3 (range: 0.1– 840), 71.8 (range: 0.1– 910), 238.1 (range: 0.1– 5150.8), and 1 (range: 0.1– 5.2) 10³/μL, respectively. Patients with above median ALRI scores were less likely to achieve an ORR as compared to those with below median ALRI values (132 (132/163, 81%) vs 150 (150/163, 92%), p = 0.004). On univariate analysis, patients with above median pretreatment NLR (HR 1.41, 95% CI: 1.09– 1.83, p = 0.01) and below median lymphocyte count (HR 0.69, 95% CI: 0.53– 0.92, p = 0.01) had significantly worse PFS. The relationship between PFS and NLR (p = 0.08) as well as lymphocytes (p = 0.20) no longer remained on multivariate analysis. On univariate analysis, below median pretreatment NLR (HR 1.72, 95% CI: 1.2– 2.45, p = 0.003) and ALRI (HR 1.52, 95% CI: 1.05– 2.2); p = 0.03) as well as above median lymphocyte count (HR 0.48, 95% CI: 0.34– 0.7, p < 0.0001) were associated with improved OS. The significant relationship between lymphocytes and OS remained on multivariate analysis (HR 0.50, 95% CI: 0.28– 0.9, p = 0.02), but the relationship with NLR (p = 0.94) did not persist. Conclusion: NLR is predictive of PFS and OS in patients with HCC undergoing TACE and may be superior to other inflammatory scores (PLR, ALRI, and SII) in this setting. However, lymphocyte count may be most predictive of OS.