The caudate lobe is located between the bilateral hepatic lobes and is divided into three subsegments: the Spiegel lobe, paracaval portion, and caudate process. The caudate artery arises from various sites of the bilateral hepatic arteries as an independent branch, common trunk, or arcade. Extrahepatic arteries can enter the caudate lobe mainly by the right inferior phrenic artery. The caudate artery also supplies the main bile duct and posterior aspect of segment IV. Although catheterization into the caudate artery is occasionally difficult because of its small size and sharp angulation, selective embolization of a tumor feeder is a significant prognostic factor in patients with hepatocellular carcinoma originating there. Therefore, we should recognize the peculiarity of its vascular anatomy and should be familiar with catheterization and embolization techniques.

Purpose: Image-guided percutaneous drainage for abscesses is known as a safe and effective treatment. The computed tomography-guided percutaneous drainage kit Drainaway (SB Kawasumi Co., Ltd.), developed on the basis of a modified trocar method, has made it possible to complete the procedure only under computed tomography guidance without radiographic fluoroscopy. This study investigated the feasibility and safety of Drainaway for abscess drainage.

Material and Methods: In this retrospective observational study, 28 procedures in 27 patients (18 men and 9 women; age 67.0 ± 12.3 years) who underwent computed tomography-guided drainage using Drainaway between March and December 2021 at seven affiliated hospitals were analyzed. Patients with symptomatic, puncturable on computed tomography and refractory abscesses were included. Technical success (successful drainage with computed tomography alone), primary clinical success (successful drainage with Drainaway alone), secondary clinical success (avoidance of surgery), and complications were evaluated.

Results: The sites of the abscesses were the intraperitoneal, retroperitoneal, and thoracic cavities in 19, 5, and 2 patients, respectively, and subcutaneous tissue in 1 patient. The mean size of the abscesses was 7.1 ± 3.4 cm. The technical success rate was 96.4%; the ligament of the puncture route could not be penetrated in one case. The primary clinical success rate was 77.8%, whereas the secondary clinical success rate of catheter upsizing or replacement was 96.3%. Complications included one case of biliary pleurisy that required drainage.

Conclusions: Drainaway is a useful device that allows abscess drainage using only computed tomography guidance without radiographic fluoroscopy.

Purpose: To evaluate risk factors for bleeding events in coronavirus disease 2019 (COVID-19) patients on extracorporeal membrane oxygenation (ECMO) and to share the initial results of transcatheter arterial embolization (TAE) for hemostasis.

Material and Methods: Forty-three COVID-19 patients who received ECMO from May 2020 to September 2021 were enrolled in this study. Patients with sudden onset anemia immediately underwent computed tomography to assess bleeding. We compared laboratory data, duration of ECMO, hospitalization period, and fatality of patients' groups with and without significant hemorrhagic events using the chi-square test and Mann-Whitney U test. We also assessed the results of TAE in patients who received hemostasis.

Results: A total of 25 bleeding events occurred in 24 of the 43 patients. Age was a risk factor for bleeding events and fatality. The average duration of ECMO and hospitalization period were significantly longer in those with bleeding events (42.9 and 54.3 days) than in those without bleeding events (16.2 and 25.0 days) (p < 0.05). In addition, those with bleeding had higher fatality (45.8%) than those without (15.8%) (p < 0.05). Active extravasation was confirmed for 5 events in 4 of 24 patients. TAE was attempted and performed successfully in all but one of these four cases, in whom bleeding ceased spontaneously.

Conclusions: Elderly COVID-19 patients on ECMO had a greater risk of bleeding complications and fatal outcomes. TAE was effective in providing prompt hemostasis for patients who have the treatment indication.

Purpose: This study aims to evaluate the efficacy of preemptive embolization (PE) of the lumbar arteries (LAs) and inferior mesenteric artery (IMA) (PELI) for preventing abdominal aortic aneurysm (AAA) enlargement associated with type 2 endoleak (T2EL).

Material and Methods: Patients who underwent endovascular aneurysm repair (EVAR) between January 2015 and December 2020 were classified into the control (without PE), IMA (PE of a patent IMA with a diameter ≥2.5 mm), and PELI (PE of patent LAs with a diameter ≥2 mm and IMA) groups. The rate of freedom from AAA enlargement following EVAR (enlargement ≥5 mm from pre-EVAR) was compared using the log-rank test. The prevalence of T2EL at 6 months and 1 year after EVAR was compared using Fisher's exact test.

Results: The cumulative rates of freedom from AAA enlargement at 54 months after EVAR (maximum observational period in the PELI group) were as follows: control group, 77.5%; IMA group, 62.5%; and PELI group, 100%. The mean CT follow-up periods of the control, IMA, and PELI groups were 46.4 ± 22.3, 31.1 ± 20.6, and 22.9 ± 15.5 months, respectively. None of the 31 patients in the PELI group experienced AAA enlargement after EVAR, whereas 2 out of the 16 patients in the IMA group and 20 out of the 98 patients in the control group had AAA enlargement. No significant differences were observed in the rate of freedom from AAA enlargement (PELI group vs. IMA group, P = 0.11; PELI group vs. control group, P = 0.11). The prevalence of T2EL was significantly lower in the PELI group than in the control group at 6 months (13.6% in PELI group vs. 42.1% in control group, P = 0.02) and 1 year (14.3% in PELI group vs. 40.0% in control group, P = 0.04).

Conclusions: PELI was significantly associated with a low prevalence of T2EL and may prevent T2EL-associated AAA enlargement.

Purpose: Renal artery embolization is a minimally invasive and effective procedure for renal ablation, a complete necrosis of the renal parenchyma. This study aims to compare the extent of renal damage in swine following renal artery embolization with ethanol and N-butyl-2-cyanoacrylate, commonly used as embolic materials in renal ablation.

Material and Methods: Three different embolic mixtures were prepared for renal artery embolization in swine: 33% ethanol-Lipiodol mixture (ethanol:Lipiodol = 1:2; Group A), 67% ethanol-Lipiodol mixture (ethanol:Lipiodol = 2:1; Group B), and 10% N-butyl-2-cyanoacrylate-Lipiodol mixture (N-butyl-2-cyanoacrylate:Lipiodol = 1:9; Group C). Three swine were assigned to each group and underwent embolization of the unilateral renal artery. Renal arteriography was performed before, immediately after, and two days after renal artery embolization. After two days, the kidneys were removed to determine the macroscopic necrosis rate and for histologic examination. Dark tissue regions were considered necrotic.

Results: The macroscopic necrosis rate of the kidneys was 50.3%±7.4%, 100%±0%, and 100%±0% in Groups A, B, and C, respectively. The necrosis rates were higher in Groups B and C than in Group A. Histologically, the renal tubules were damaged in the necrotic areas. In addition, the glomeruli were damaged in Groups A and B but were preserved in Group C.

Conclusions: Sixty-seven percent ethanol-Lipiodol mixture and 10% N-butyl-2-cyanoacrylate-Lipiodol mixture are effective embolic materials in renal artery embolization for renal ablation in swine. Also, ethanol caused partial glomerular necrosis, whereas N-butyl-2-cyanoacrylate preserved the glomeruli. Therefore, ethanol should be used for renal ablation.

We present an interventional radiology technique for percutaneous trans-jejunal pancreatojejunostomy reconstruction for intractable pancreatic fistula. A 70-year-old man with pancreatic cancer who had undergone pancreatoduodenectomy underwent percutaneous drainage for leakage from the anastomosis of the pancreatic duct to the jejunum. The leakage continued and the hole at the anastomosis site in the jejunum closed completely after 5 months. We performed percutaneous jejunostomy; the previously placed drainage catheter was then replaced with a balloon catheter, which was punctured by a 19-gauge needle from inside the jejunum through the percutaneous jejunostomy tube. The seeking catheter was inserted into the pancreatic duct. Finally, a side-holed 6-Fr straight catheter was successfully placed in the pancreatic duct through the percutaneous jejunostomy route.

Jejunal artery aneurysms are extremely rare; only 58 cases have been reported up to 2022. The high rupture rate necessitates a curative treatment. Only four cases of true jejunal artery aneurysms treated with endovascular embolization were reported. We report a case of a 75-year-old man with a true jejunal artery aneurysm who was successfully treated with endovascular embolization. The aneurysm was located in the third jejunal branch. The proximal and distal distance to the superior mesenteric artery and the first bifurcation of the third jejunal branch, respectively, were too short to perform isolation. First, we performed packing in the aneurysm, followed by secondary parent artery embolization. Finally, we achieved total occlusion of the aneurysm and its parent artery with preserved distal intestinal blood flow.

Purpose: We aim to evaluate retrospectively the feasibility, safety, and initial therapeutic outcomes of radiofrequency ablation combined with hepatic artery embolization using a tris-acryl gelatin microsphere for colorectal liver metastases.

Material and Methods: Six consecutive patients (4 men and 2 women) with median age of 68 years (range 57-78 years) underwent computed tomography fluoroscopy-guided radiofrequency ablation immediately after hepatic artery embolization using microspheres. This study evaluated tumor visibility on noncontrast-enhanced computed tomography immediately after hepatic artery embolization; analyzed local tumor progression; defined technical success as the coverage of the tumor by the ablative zone; and assessed adverse events based on Common Terminology Criteria for Adverse Events v5.0.

Results: Ten tumors with median maximum diameter of 9 mm (range 5-52 mm) were treated in nine sessions. Eight tumors (80%, 8/10 tumors) were detected as high-attenuation nodules. One tumor was treated in two sessions because follow-up computed tomography revealed an insufficient ablative margin. Therefore, the primary and secondary technical success was 90% (9/10 tumors) and 100% (10/10 tumors), respectively. Grade 2 pneumothorax was observed in one session (11%, 1/9 sessions). No grade 3 or higher adverse event was observed. The local tumor progression rate was 20% (2/10 tumors) during the median follow-up of 14 months.

Conclusions: Radiofrequency ablation following microsphere embolization may be a feasible, safe, and useful therapeutic option for controlling small colorectal liver metastases.

Injury of the visceral artery is a potentially fatal complication of iatrogenic procedures, trauma, and tumors. A stent graft can achieve rapid exclusion of the injured arterial portion and minimize the risk of ischemic complications by preserving arterial flow to organs. Although various types of stent grafts are available worldwide, Viabahn has only been approved for visceral arterial injury in Japan. The reported technical and clinical success rates, including cases with injured pelvic or thoracic arterial branches, are 80%-100% and 66.7%-100%, respectively. Severe ischemic complications are rare; however, fatal ischemia occurs when the stent graft is immediately occluded. The necessity of antiplatelet therapy is controversial, and a target artery diameter ≤ 4 mm is a significantly higher risk factor of stent-graft occlusion.