Purpose: Distal transradial access through the anatomical snuffbox has been highlighted in recent research because it provides extremely low invasiveness. It has demonstrated its feasibility and safety for cardiac intervention. However, its characteristics for noncardiac intervention are not well known. This report aims to demonstrate the feasibility and safety of noncardiac intervention with distal transradial access, with identification of practical devices for procedures.

Material and Methods: This retrospective study was conducted from May 2021 to December 2021 with consecutive patients who underwent distal transradial access for noncardiac intervention. This study analyzed patient physical information, procedural details, technical success rates, and distal transradial access-associated complications.

Results: Nine patients (7 females, 2 males) aged 48-69 years (median: 57) were enrolled in this study. This study assessed 11 noncardiac procedures, such as transarterial infusion chemotherapy for head and neck malignancies (n = 4), embolization of visceral artery aneurysm (n = 2), embolization of renal angiomyolipoma (n = 2), percutaneous transluminal renal angioplasty (n = 1), bronchial artery embolization (n = 1), and diagnostic angiography (n = 1). The introducer sheath size was 4-6 French. Catheters respectively having nine tip shapes were used. Reverse curve catheters were used only in two cervical procedures. The technical success rate was 91% (10/11). Of the 11 procedures, only 1 (bronchial artery embolization) required conversion to transfemoral access. There was no complication associated with distal transradial access. Ultrasound evaluation after treatments revealed patent radial arteries in all patients.

Conclusions: Results revealed that distal transradial access is feasible with commercially available catheters and is safe for various noncardiac interventions.

Purpose: A membranous structure (MS) may be seen on ultrasound at a site of vascular access (VA) stenosis in patients on hemodialysis. It can also be encountered during percutaneous transluminal angioplasty (PTA) and be impassable from one side but easily passed from the other. This study aimed to examine the characteristics of MS cases and how to treat them.

Material and Methods: Percutaneous transluminal angioplasty performed at our hospital for arteriovenous fistula-vascular access stenosis between July 2021 and June 2022 were identified. They were divided into two groups: membranous structure and nonmembranous structure. Data of patients such as age, history of dialysis and vascular access use, number of percutaneous transluminal angioplastys performed for vascular access, and diabetes status were collected. Membranous structure cases were examined in terms of puncture direction.

Results: A total of 72 percutaneous transluminal angioplasty were performed in 37 patients. Membranous structure was identified in nine percutaneous transluminal angioplastys. Patients with membranous structure were older than those without membranous structure (mean age 75.3 ± 7.54 vs. 70.0 ± 10.8 years, P = 0.21) and tended to have a history of vascular access use (57.6 ± 106 vs. 48.4 ± 59.8 months, P = 0.28), a history of dialysis (152 ± 95.6 vs. 91.2 ± 116 months, P = 0.02), fewer percutaneous transluminal angioplasty procedures (1.44 ± 0.726 vs. 3.24 ± 2.69, P = 0.02), and lower incidence of diabetes (1 vs. 38 cases). In the nonmembranous structure group, all percutaneous transluminal angioplastys performed were successful. In the membranous structure group, six percutaneous transluminal angioplastys were successful, two were impassable, and one was acutely occluded. The successful cases and the acute obstruction case were passed by centrally directed puncture. Impassable cases involved peripheral directional puncture.

Conclusions: Vascular access stenosis can be caused by membranous structure and successfully treated by bidirectional puncture.

Computed tomography-guided puncture is a useful technique for various interventional radiology procedures. Puncture from various locations and angles becomes possible using this technique. Moreover, bone and air do not interfere with the computed tomography image. Therefore, computed tomography-guided puncture is feasible even in difficult cases of ultrasonography-guided procedures. However, a computed tomography-guided procedure can cause radiation exposure to patient and operator. Therefore, utmost attention should be given to minimizing radiation exposure.

This study aimed to provide a brief review of pre-procedural preparation and the technical tips for the computed tomography-guided puncture and introduce recent topics related to the radioprotection of computed tomography-guided puncture.

Nonocclusive mesenteric ischemia (NOMI) is a condition characterized by segmental or discontinuous mesenteric ischemia and intestinal necrosis without an organic obstruction in the mesenteric vessels. Diagnosis is challenging, and early intervention is crucial for improving patient outcomes. Various factors such as background factors, symptoms, biomarkers, and imaging techniques contribute to the diagnosis. Ensuring an early diagnosis and prompt treatment is of paramount importance. Although studies reported on the effectiveness of intra-arterial vasodilator infusion therapy as an endovascular treatment, its future role remains uncertain. Therefore, this review primarily aimed to provide a comprehensive summary of the advancements in the current state of NOMI management, with a specific emphasis on the implementation of endovascular therapy.

Acute portal vein thrombosis is characterized by nonspecific abdominal pain, causing severe morbidity and mortality. Prompt diagnosis is crucial to avoid short-term complications such as intestinal infarction, sepsis, and death. The therapeutic goal is to prevent thrombus extension into the mesenteric veins and intestinal ischemia complications. Systemic anticoagulation is the standard treatment. However, endovascular treatments such as thrombolysis, thrombectomy, balloon angioplasty, stent placement, and transjugular intrahepatic portosystemic shunt placement have been performed in patients who are refractory to anticoagulation therapy or at a high risk of intestinal ischemia. This review discusses the clinical and diagnostic considerations in acute portal vein thrombosis, focusing on current endovascular treatments that are effective and safe. However, prospective data are required to compare endovascular treatment techniques and assess their outcomes.

Pelvic fractures are severe trauma that can cause hemorrhagic shock. The mortality rate is high when patients fall into shock. Therefore, prompt diagnosis and treatment are necessary. Hemostasis for hemorrhage associated with pelvic fractures is achieved through the mechanical stabilization of the fracture site, preperitoneal pelvic packing, and transcatheter arterial embolization. These techniques are frequently employed in hemodynamically unstable patients presenting with pelvic fractures. Among them, transcatheter arterial embolization is often considered the first-line choice: it is a particularly effective hemostatic method for arterial hemorrhage caused by pelvic fracture. An embolization technique and embolic agents should be considered comprehensively while considering the patient's hemodynamics, angiographic findings, and the urgency of the situation. This article describes the indications, techniques, results, and complications of transcatheter arterial embolization for pelvic fractures.

Transarterial chemoembolization is still an effective treatment option for hepatocellular carcinoma worldwide and is categorized into conventional transarterial chemoembolization with ethiodized oil transarterial chemoembolization and transarterial chemoembolization with drug-eluting spherical material transarterial chemoembolization. Several randomized controlled trials conducted in Europe have shown the equivalent efficacy of ethiodized oil transarterial chemoembolization and drug-eluting spherical material transarterial chemoembolization. However, a recent randomized controlled trials in Japan established the superiority of ethiodized oil transarterial chemoembolization in terms of complete response rates although higher liver toxicity for ethiodized oil transarterial chemoembolization. Nevertheless, the survival advantage of ethiodized oil transarterial chemoembolization is yet to be substantiated. The adverse effects of drug-eluting spherical material transarterial chemoembolization are milder than those of ethiodized oil transarterial chemoembolization, rendering drug-eluting spherical material transarterial chemoembolization an advantageous option for patients with bilobar tumors and impaired liver function/performance status. This article aims to provide an overview of these embolization techniques and a review of recent literature.

Magnetic resonance imaging (MRI) is one of the guiding modalities used for percutaneous needle insertion during interventional procedures. MRI guidance has several advantages, including multiplanar imaging capability, superior soft tissue contrast resolution, and the absence of ionizing radiation. When performing MRI-guided procedures, it is important to understand the suitable MRI systems, instruments, and imaging sequences for intervention. Furthermore, needle artifact characteristics must be fully understood to ensure safe and accurate needle insertion. In this article, we present the fundamental knowledge as regards the use of MRI guidance for percutaneous needle insertion and review its usefulness in representative interventional procedures, such as biopsy and tumor ablation.

Splenic injury is one of the most common abdominal parenchymal organ injuries.

Since the spleen is a parenchymal organ with abundant blood flow, its injury can easily result in hemorrhagic shock. Therefore, prompt and appropriate management for hemostasis is critical. Management of splenic injury is determined by the hemodynamic status and the grade of injury. Splenectomy is the primary choice in cases with unstable hemodynamics, but splenic repair or non-operative management, including conservative treatment or transcatheter arterial embolization (TAE), may be chosen to preserve the spleen if time permits. Non-operative management has advantages over operative management in terms of complications and medical economics. TAE also plays a significant role in non-operative management by contributing to the improvement of patient outcomes.

Barcelona Clinic Liver Cancer staging system, which has been identified as the most commonly used staging system in patients with hepatocellular carcinoma, was initially published in 1999, and it was updated in 2022. This new Barcelona Clinic Liver Cancer staging shows more flexible strategies for the treatment of hepatocellular carcinoma based on each stage. Although the roles of trans-arterial chemoembolization were limited in intermediate stage (Barcelona Clinic Liver Cancer-B) patients in the previous version, its roles have been expanded in the new version of Barcelona Clinic Liver Cancer staging system. In this manuscript, we introduce how trans-arterial chemoembolization is incorporated in a new Barcelona Clinic Liver Cancer staging system and explore the new role of trans-arterial chemoembolization and what interventional radiologists seek for in a near future.

One of the major reasons for unresectability of the liver is that the remnant liver volume is insufficient to support postoperative liver function. Post-hepatectomy liver insufficiency is one of the most serious complications in patients undergoing major hepatic resection. Preoperative portal vein embolization is performed with the aim of inducing hypertrophy of the future liver remnant and is thought to reduce the risk of liver insufficiency after hepatectomy. We, interventional radiologists, are required to safely complete the procedure to promote future liver remnant hypertrophy as possible and understand portal vein anatomy variations and hemodynamics, embolization techniques, and how to deal with possible complications. The basic information interventional radiologists need to know about preoperative portal vein embolization is discussed in this review.

Superselective intra-arterial chemoradiotherapy for head and neck cancer is a combination of intensive local delivery of anticancer drugs using microcatheters and external beam radiation. Unlike conventional chemoradiotherapy, it is highly effective in treating the primary tumor, but it cannot treat distant metastases. In the field of head and neck cancer, where quality of life is significantly impaired by curative surgery from a functional and cosmetic point of view, it is a useful treatment not only for unresectable cases but also for resectable advanced cancers, with the maxillary sinus being a particularly good indication. This treatment is expected to outperform conventional systemic chemotherapy and even comes close to the outcomes of radical surgery if the patient is carefully selected and the appropriate technique is used. Currently, a multicenter phase III clinical trial to evaluate the efficacy of this treatment for maxillary sinus cancer has been completed, and the results are being analyzed.

It is more than 50 years since the concept of transjugular intrahepatic portosystemic shunt (TIPS) was first introduced as a percutaneous procedure for patients with refractory variceal bleeding and ascites. TIPS has become widely accepted in the management of complications of portal hypertension because it is less invasive than surgery. In the early days of TIPS, complications included the poor long-term patency of the stent and a high incidence of hepatic encephalopathy. In addition, an excessive shunt diameter after TIPS often resulted in severe hepatic encephalopathy. Although recent covered stents have significantly reduced shunt dysfunction, the development of hepatic encephalopathy and early liver failure remain to be crucial post-TIPS complications. This study reviews the current literature on the status of TIPS in the treatment of cirrhosis.

In 2008, carotid artery stenting was formally approved in Japan. Since then, more than fourteen years have already passed. Much evidence concerning carotid artery stenting has already been published, and several new devices are available. Thus, indications and procedures for carotid artery stenting have changed. In this review, I describe the current status of carotid artery stenting by literature review with particular focus on the evidence regarding its effectiveness and safety, history with the transition of devices in Japan, and complications related to carotid artery stenting procedures. A recent topic (a new category of subtype of carotid stenosis) is also mentioned briefly.