Endovascular embolization agents are particles and fluids that can be released into the bloodstream through a catheter to mechanically and/or biologically occlude a target vessel, either temporarily or permanently. Vascular embolization agents are available as solids, liquids, and suspensions. Although liquid adhesives (glues) have been used as embolic agents for decades, experience with them for peripheral applications is generally limited. Cyanoacrylates are the main liquid adhesives used for endovascular interventions and have a major role in managing vascular abnormalities, bleeding, and many vascular diseases. They can only be injected as a mixture with ethiodized oil, which provides radiopacity and modulates the polymerization rate. This review describes the characteristics, properties, mechanisms of action, modalities of use, and indications of the cyanoacrylate-Lipiodol^® combination for peripheral embolization.

Percutaneous sclerotherapy is used to treat venous and lymphatic vascular malformations, which can cause significant discomfort and/or disfigurement. The purpose of this study is to describe the bleomycin sclerotherapy technique and to evaluate its clinical and radiological efficacy and safety. We retrospectively identified consecutive patients with venous malformations (VMs) and lymphatic malformations (LMs) who underwent bleomycin sclerotherapy in 2011–2020 at our institution. We collected the clinical and radiological success rates, complications and recurrences separately in the VM and LM groups. We identified 26 patients, 15 with VMs and 11 with LMs. The significant volume reductions obtained were 45% in the VM group and 76% in the LM group (p = 0.003 and p = 0.009, respectively). Significant reductions in discomfort/pain and in cosmetic disfigurement were obtained in both groups. An overall improvement was reported by 69% and 82% of patients in the VM and LM groups, respectively. No major complications occurred during the mean follow-up of 51 ± 34 months in the VM group and 29 ± 18 months in the LM group. A recurrence developed within 2 years in 23% of patients. Bleomycin is clinically and radiologically effective for the treatment of venous and lymphatic malformations, with a high level of patient safety.

Selective arterial embolization (SAE) for renal angiomyolipoma (rAML) is effective to treat or prevent bleeding. We report our experience using a cyanoacrylate–Lipiodol mixture. We performed a single-center retrospective review of all rAMLs embolized with cyanoacrylate glue between July 2014 and June 2020. Demographics, tuberous sclerosis complex (TSC) status, clinical presentation, angiography features, and follow-up data were recorded. Pre- and post-procedure rAML sizes and volumes were estimated from computed tomography (CT) or magnetic resonance imaging (MRI) studies. Kidney function was assessed before and after the procedure. We identified 24 patients (22 females and 2 males, mean age 51 years) treated for 27 AMLs, either prophylactically (n = 20) or as an emergency (n = 4). Technical success was achieved for 25/27 AMLs; two patients, each with a single AML, required nephrectomy and repeated embolization, respectively. Major complications occurred in three patients and minor complications such as postembolization syndrome in 15 patients. AML volume reduction after embolization was 55.1% after a mean follow-up of 15 months (range, 1–72 months). Factors associated with greater volume reduction were a smaller percentage of fat (p = 0.001), larger initial rAML volume (p = 0.014), and longer follow-up (p = 0.0001). The mean creatinine level did not change after SAE. Embolization of rAMLs with a mixture of cyanoacrylate and Lipiodol is feasible, safe, and effective in significantly decreasing tumor volume.

Diffusion weighted imaging (DWI) and intravoxel incoherent motion (IVIM) have been explored to assess liver tumors and diffused liver diseases. IVIM reflects the microscopic translational motions that occur in voxels in magnetic resonance (MR) DWI. In biologic tissues, molecular diffusion of water and microcirculation of blood in the capillary network can be assessed using IVIM DWI. The most commonly applied model to describe the DWI signal is a bi-exponential model, with a slow compartment of diffusion linked to pure molecular diffusion (represented by the coefficient D_slow), and a fast compartment of diffusion, related to microperfusion (represented by the coefficient D_fast). However, high variance in D_fast estimates has been consistently shown in literature for liver IVIM, restricting its application in clinical practice. This variation could be explained by the presence of another very fast compartment of diffusion in the liver. Therefore, a tri-exponential model would be more suitable to describe the DWI signal. This article reviews the published evidence of the existence of this additional very fast diffusion compartment and discusses the performance and limitations of the tri-exponential model for liver IVIM in current clinical settings.

Liver tumors are common and may be unamenable to surgery or ablative treatments. Consequently, other treatments have been devised. To assess the safety and efficacy of transarterial radioembolization (TARE) with Yttrium-90 for hepatocellular carcinoma (HCC), liver-dominant hepatic colorectal cancer metastases (mCRC), and cholangiocarcinoma (CCA), performed according to current recommendations, we conducted a single-center retrospective study in 70 patients treated with TARE (HCC, n = 44; mCRC, n = 20; CCA, n = 6). Safety and toxicity were assessed using the National Cancer Institute Common Terminology Criteria. Treatment response was evaluated every 3 months on imaging studies using Response Evaluation Criteria in Solid Tumors (RECIST) or mRECIST criteria. Overall survival and progression-free survival were estimated using the Kaplan-Meier method. The median delivered dose was 1.6 GBq, with SIR-Spheres^® or TheraSphere^® microspheres. TARE-related grade 3 adverse events affected 17.1% of patients. Median follow-up was 32.1 months. Median progression-free survival was 5.6 months and median overall time from TARE to death was 16.1 months and was significantly shorter in men. Progression-free survival was significantly longer in women (HR, 0.49; 95%CI, 0.26–0.90; p = 0.031). Risk of death or progression increased with the number of systemic chemotherapy lines. TARE can be safe and effective in patients with intermediate- or advanced-stage HCC, CCA, or mCRC refractory or intolerant to appropriate treatments.

To evaluate the feasibility and safety of percutaneously implanted arterial port catheter systems for hepatic arterial infusion of chemotherapy (HAI) in patients with unresectable liver malignancies. From October 2010 to August 2018, arterial port catheters for HAI were percutaneously implanted in 43 patients with unresectable liver malignancies. Three different catheter placement techniques were compared: a conventional end-hole catheter placed in the common hepatic artery (technique 1, n = 16), a side-hole catheter with the tip fixed in the gastroduodenal artery (technique 2, n = 18), and a long-tapered side-hole catheter with the tip inserted distally in a segmental hepatic artery (technique 3, n = 6). Catheter implantation was successful in 40 (93%) of the 43 patients. Complications related to catheter placement were observed in 10 (23%) patients; 5 (83%) of the 6 major complications were resolved, as well as all 4 minor complications. Catheter migration and occlusion occurred in 9 (22.5%) patients. Catheter migration was more frequent with technique 1 (n = 6) than with technique 2 (n = 1), although the difference was not significant (p = 0.066). Percutaneous arterial port catheter implantation for HAI is highly feasible and carries a low risk of complications.