Administration of antithrombotic agents in neuroendovascular therapy is important to prevent periprocedural thromboembolic complications. Both anticoagulants that prevent red thrombi formed by flow stagnation in the catheter and antiplatelets that prevent white thrombi triggered by the implanted foreign body, such as coils and stents, are needed. With the progress of endovascular techniques and development of new devices, periprocedural antiplatelet therapy has been used more aggressively in recent years. Currently, the standard antiplatelet management in many neuroendovascular treatments is dual antiplatelet therapy. Perioperative antithrombotic therapy may reduce ischemic complications, but it presents the potential risk of hemorrhagic complications. Moreover, long-term dual therapy does not reduce the risk of stroke recurrence and is associated with an increased risk of major bleeding events. For patients at high risk for hemorrhagic complications, the physician should undertake measures, such as reducing the dose or discontinuing it early.Intracranial aneurysm rupture is the main fatal complication of coil embolization for an intracranial aneurysm performed in conjunction with systemic heparinization. We answered five clinical questions about anesthesia, systemic heparinization, intraoperative aneurysmal rupture, the balloon-assisted technique, and the next step of initial response in case of aneurysmal rupture. It is crucial to understand when and why intraoperative aneurysmal rupture occurs to reduce its mortality rate. In cases of intraoperative problems, never pull the microcatheter or coil when perforating an aneurysm; lowering blood pressure, administering protamine for the reversal of heparin, and occluding blood flow into an aneurysm by inflating balloon(s) will help in the treatment. It is our pleasure that this chapter will help in your daily care.More than 2000 patients with large aneurysms have been treated with PipelineTM Flex since approval in 2015. The indication of PipelineTM Flex has expanded according to the PREMIER trial.  https://www.selleckchem.com/products/bpv-hopic.html  Moreover, FREDTM has been approved in 2020 with a wider indication compared to that of PipelineTM. Aneurysms with 5 mm or larger of the maximum diameter in the internal carotid artery(ICA)and vertebral artery(VA)are currently indicated for PipelineTM. Moreover, the indications for FREDTM include the proximal anterior cerebral, proximal middle cerebral artery, and basilar artery in addition to the ICA and VA. The use in the acute stage of subarachnoid hemorrhage remains contraindicated for both. One should note several specific technical tips for these flow diverters. FREDTM can be deployed more easily compared to PipelineTM due to the large caliper filament and the flare ends. However, FREDTM is generally resistant to balloon angioplasty after it is fully deployed, most probably because the anchored flare ends disable foreshortening of FREDTM. Concomitant use of coiling may be recommended for intradural aneurysms to potentially minimize the risk of delayed rupture.We introduce typical use cases and the appropriate use of balloon catheters and neck bridge stents for coil embolization of cerebral aneurysm. There are two types of balloon catheters single-lumen and double-lumen catheters. They are also classified into compliant and super-compliant balloons by softness. Neck bridge stents are classified into two types open-cell and closed-cell stents. Balloon- and stent-assisted techniques are both useful for wide-neck aneurysms. The complication rates of these methods are similar but the stent-assisted technique requires long-term administration of antiplatelets after the procedure. Both techniques have the challenge that the microcatheter is fixed during coil embolization. The semi-jailing technique, in which the stent is partially deployed during coil insertion, solves this problem. Open-cell stents seem more suitable for this technique because they fit better to the vessel wall even in the curved part. It is important to understand the characteristics of each device for safe and effective treatments.The first coil should be as thick, long, and large as possible. A retrospective study at the Toranomon Hospital revealed that if the volume of the first coil is 1/3rd or more of the total coil volume, there are less chances of retreatment. Thus, a thick and long first coil contributes to stable long-term anatomical results. The length of the first coil should be approximately 8% of the volume of the aneurysm. After the placement of the first coil, a smaller and shorter coil should be placed sufficiently close to it to complete the procedure. The goal is to achieve prevention of acute re-rupture in ruptured acute aneurysms and life-long prevention of rupture in unruptured asymptomatic aneurysms. If the coil does not detach, check the position of the detachment point, and replace the power supply. In addition, refer to the direction for use of the device for prevention of coil disconnection failure and countermeasures. Although it is not a recommended method, a method of rotating the delivery wire at the detached position to thread the coil and a method of reconstructing the electric circuit with a crocodile clip has been reported.The goal of coil embolization for cerebral aneurysms is to occlude the cerebral aneurysm to prevent rupture while maintaining the patency of the parent artery. The integrity of cerebral aneurysm occlusion is affected by many factors, including cerebral aneurysm morphology, dome-neck size, dome-neck ratio, and the location of the aneurysm and its parent artery. These factors are then considered pre-operatively and the position of each catheter that allows for the most efficient embolization is assumed. To navigate each catheter to the ideal position, it is necessary to know the characteristics(shape, flexibility, size, etc.)of each catheter. In addition, it is necessary to know the procedure and positioning of balloon catheters or stenting catheters if you use adjunctive techniques. This article will provide guidance for beginners who start coil embolization and provide basic knowledge of how to use catheters, their combinations, and basic methods to help the physician performing optimal coil embolization.