N-butyl-cyanoacrylate is liquid adhesive non-absorbable embolic material whose permeability is very stable. Such materials must be liquid at the time of injection and should solidify when they reach the pathological angioarchitecture, producing an endovascular cast of the area without passing into the venous circulation or distal arterial territory. If superselectivity is accomplished and no normal or endangered vessels are present, one can inject acrylic as a continuous column to produce an intravascular cast. An important part of the management of angioma is educating the patient. NBCA embolization for arteriovenous malformation can be carried out as a unique treatment, the intended goal being partial and targeted, palliative, curative, or in combination with surgery or stereotactic radiosurgery. It may be given as elective treatment or in emergent fashion, depending on the indication and circumstances. The indication to use this embolic material should be well considered in the clinical management of angioma and the arteriovenous malformation in the central nervous system.

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Although most cases of acute gastrointestinal (GI) bleeding are managed by conservative or endoscopic treatment, there are still some patients who should receive more aggressive treatment. Transcatheter arterial embolization has been widely accepted for the treatment of life threatening acute upper and lower GI bleeding. Although the development of microcatheters and microcoils has enabled us to perform more distal embolization, it may be sometimes difficult to advance the microcatheter to the bleeding point because of vascular tortuosity and also to achieve complete hemostasis in patients with coagulopathy. N-butyl cyanoacrylate (NBCA) allows rapid and permanent embolization just after contact with blood and achieves complete hemostasis with the collateral vessels occlusions. NBCA embolization takes less time than conventional coil embolization and can prevent recurrent bleeding with a low risk of critical gastrointestinal ischemia, especially when the patient has an unstable hemodynamic state because of massive bleeding. Interventional radiologists should be familiar with the use of NBCA preparing for such a serious condition.

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Gelatin sponge and polyvinyl alcohol particles have been the most popular particulate embolic agents for hypervascular tumors, arterial bleedings and vascular malformations. Over the last decade, calibrated microspheres have been introduced and increasingly used especially in uterine fibroid embolization in Western countries. In addition, drug-eluting microspheres have been applied for liver tumor embolization. The advantages of these microspheres are that particles are uniform in size and shape, and easy to inject through a microcatheter. They can travel distally to vessels corresponding to the particle size; in other words, the occlusion level can be predictable according to the particle size chosen. However, there are also pitfalls associated with the use of microspheres. Temporary aggregation and redistribution of microspheres may allow resumption of the blood flow of once apparently occluded vessels. Microspheres with low elasticity and rigidity may migrate more distally than desired due to particle deformation. The mechanical properties of drug eluting beads may alter upon drug loading and release. Therefore, we need to understand the behavior of each type of microsphere to obtain the optimal embolic effects. It is also important to investigate the true benefits of microspheres or in what pathological conditions they will improve the safety and efficacy compared to the conventional materials.

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Transcatheter arterial embolization (TAE) is an important technique in Interventional radiology (IVR), and metallic coils play an important role as an embolic material. Coil was developed by Dr. Ceaser Gianturco in 1975, and was introduced to Japan by COOK/Medicos Hirata 35 years ago. So far various types of coil have been developed and become remarkably wide spread. They are an essential medical device in IVR as a less invasive therapy. Coils are available in a wide variety of sizes and shapes, which are made from either stainless steel or platinum and may have Dacron fibers placed. Indications of coil include embolization of aneurysm, arteriovenous malformation, arteriovenous shunt, vascular lesions causing massive hemorrhage and alteration of blood supply before chemoinfusion therapy. It is very important to understand the kinds, size, shape, and features of coils and to select the appropriate coil for each organ and lesion. Interventional radiologists are required to gain special techniques and knowledge about coils to achieve a good therapeutic effect without complications. This article reports fundamental knowledge about coils with presentation of clinical cases in various organs and diseases.

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Gelatin sponge particles have been used as embolic materials for more than 30 years. This embolic material has wide therapeutic applications such as chemoembolization for hepatocellular carcinoma, bleeding control and embolization of other malignant tumors, benign tumor, trauma, and gastrointestinal bleeding. This article aimed to provide information on the characteristics of gelatin sponge, role of embolic material, and method of creation of gelatin sponge. We also describe our clinical experience with soluble gelatin sponge for transcatheter chemoembolization.

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Purpose: The purpose of this study was to evaluate the usefulness of venous sac embolization using J-shaped detachable coils for the transcatheter embolization of pulmonary arteriovenous malformations (PAVM).
Materials and Methods: Six consecutive patients (two men, four women, mean age 53 years, range 27-66 years) with a total of 24 PAVM underwent transcatheter arterial coil embolization. Clinical signs of hereditary hemorrhagic telangiectasia (HTT) were present in 2 patients, while in the others PAVM appeared sporadically. We first framed the venous sac using J-shaped mechanical detachable coils. Then we filled the sac with spiral-shaped detachable mechanical coils. Where necessary we added Nester- and steel coils.
Results: Of the 24 PAVM, 16 were treated with J- and spiral-shaped mechanical detachable coils only. Two minor complications of self-limited chest pain and angina pectoris were observed in two patients. Follow-up CT confirmed the absence of recanalization in 24PAVMs of 6 patients; PAVM addressed by venous sac embolization manifested a decrease of the feeding artery to less than 3mm. None of the patients suffered symptom recurrence during follow-up the ranging from 4 to 21 months.
Conclusion: Venous sac embolization may help to prevent systemic coil migration and facilitate the safe occlusion of large venous sacs. More experience is needed to determine the value of this technique.

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Two cases of limb occlusion after endovascular repair of abdominal aortic aneurysm (AAA) with Zenith AAA endovascular graft are reported. One case of AAA had a narrowed and calcified distal aorta. The left iliac leg was stenosed at the distal aorta, and was occluded 11 days after stent-grafting. The other case had a short aneurysmal length and mild-narrowed proximal neck. The proximal ends of the bilateral iliac legs were placed within the narrowed and long proximal neck. The right iliac leg was stenosed by the pendent left iliac leg, and was occluded one month after stent-grafting. Both cases were treated with thrombectomy and SMART stent placement.

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