Endovascular management of pancreatitis-related pseudoaneurysms: A review of techniques

Endovascular Treatment of Visceral Artery Pseudoaneurysms with Ethylene-Vinyl Alcohol (EVOH) Copolymer-Based Non-Adhesive Liquid Embolic Agents (NALEAs)

Background and Objectives: Treatment of visceral artery pseudoaneurysms (VAPs) is always indicated regardless of their diameters, as their risk of rupture is significantly higher than that of visceral artery aneurysms. The invasiveness of surgery and its associated complications have led to a shift in favor of radiological interventions as the initial treatment of choice. However, there are still some unanswered questions on endovascular treatment of VAPs regarding the optimal endovascular technique and the efficacy and safety outcomes. The purpose of this multicenter study was to retrospectively evaluate the effectiveness and safety of endovascular treatment of visceral pseudoaneurysms using Ethylene-Vinyl Alcohol (EVOH) Copolymer-Based Non-Adhesive Liquid Embolic Agents (NALEAs). Materials and Methods: Consecutive patients who underwent endovascular embolization with EVOH-based NALEAs for visceral artery pseudoaneurysms between January 2018 and June 2023 were retrospectively evaluated. Results: 38 embolizations were performed. Technical success was achieved in all patients. The clinical success rate was high (92.1% overall), with no significant differences between ruptured and unruptured VAPs (p = 0.679). Seven patients (18.4%) experienced procedure-related complications, related to one case of non-target embolization, four splenic abscesses due to end-organ infarction, and two femoral pseudoaneurysms. The rates of procedure-related complications, end-organ infarction, and vascular access-site complications did not significantly differ between ruptured and unruptured VAPs (p > 0.05). Conclusions: Both ruptured and unruptured visceral pseudoaneurysms can be effectively and safely treated with NALEA-based endovascular embolization. We suggest considering the use of NALEAs, particularly in specific clinical cases that highlight their advantages, including patients with coagulopathy, fragile vessels, and embolization targets that are located at a considerable distance from the microcatheter tip and are otherwise difficult to reach.

Vascular complications of chronic pancreatitis and its management

Chronic pancreatitis is a chronic fibro-inflammatory disorder of the pancreas, resulting in recurrent abdominal pain, diabetes mellitus, and malnutrition. It may lead to various other complications such as pseudocyst formation, benign biliary stricture, gastric outlet obstruction; and vascular complications like venous thrombosis, variceal and pseudoaneurysmal bleed. Development of varices is usually due to chronic venous thrombosis with collateral formation and variceal bleeding can easily be tackled by endoscopic therapy. Pseudoaneurysmal bleed can be catastrophic and requires radiological interventions including digital subtraction angiography followed by endovascular obliteration, or sometimes with a percutaneous or an endoscopic ultrasound-guided approach in technically difficult situations. Procedure-related bleed is usually venous and mostly managed conservatively. Procedure-related arterial bleed, however, may require radiological interventions.

Hepatic artery pseudoaneurysm caused by chronic pancreatitis: Case report and literature review

RATIONALE

Visceral artery pseudoaneurysm is a rare complication of chronic pancreatitis (CP), all pancreatic or peripancreatic arteries have been reported to be involved, while hepatic artery is less common.

PATIENT CONCERNS

This case report illustrated a 42-year-old man with CP who developed right hepatic artery pseudoaneurysm (HAP), and finally he was treated with intravascular embolization.

DIAGNOSES

The patient suffered from HAP due to acute attack of CP.

INTERVENTIONS

The pseudoaneurysm located in a fine branch of right hepatic artery was embolized.

OUTCOMES

The HAP of the patient was cured. He had no recurrent bloody stool or abdominal pain. The symptoms gradually relieved.

CONCLUSION

Herein, we report a patient with CP who developed right HAP causing infected hematoma, gastrointestinal bleeding, and obstructive jaundice, and a literature review is also presented. HAP caused by CP is a rare disease in the clinic, but rupture of pseudoaneurysm is fatal. Careful evaluation, early detection, and prompt treatment should be performed when the patient is admitted and followed up.

Same Clinical Reality of Spontaneous Rupture of the Common Iliac Artery with Pseudoaneurysm Formation-Comparison of Two Therapeutical Solutions, Endovascular Stent-Graft and Open Surgical Correction, for Two Cases and Review of the Literature

The incidence of isolated iliac artery aneurysms is approximately 2% and common iliac artery pseudoaneurysms are even rarer. A pseudoaneurysm is a localized hemorrhage as opposed to an actual aneurysm, which affects the entire vascular wall. They are typically asymptomatic and only detectable accidentally while looking for other causes. If large and symptomatic, they typically exhibit pressure symptoms as a result of the compression of the structures around them. Common symptoms include generalized stomach pain, urological problems, gastrointestinal bleeding, and neurological symptoms such as leg paralysis or sciatica-like back pain. Rarely, they may exhibit hemodynamic instability together with an aneurysm rupture, which has a high fatality rate. Due to the unique presentation, the diagnosis is typically rarely made and there is little experience with treating it. We report two cases of common iliac artery pseudoaneurysm found in two patients who had no notable medical history and who we chose to repair through the endovascular technique in the first case, an approach that has gained more ground for vascular repair worldwide, making it the current go-to method, and for the second case we chose a more traditional approach, through open surgery.

Interventional radiology followed by endoscopic drainage for pancreatic fluid collections associated with high bleeding risk: Two case reports

BACKGROUND

Endoscopic ultrasound (EUS)-guided transluminal drainage is an advanced technique used to treat pancreatic fluid collections (PFCs). However, gastric varices and intervening vessels may be associated with a high risk of bleeding and are, therefore, listed as relative contraindications. Herein, we report two patients who underwent interventional embolization before EUS-guided drainage.

CASE SUMMARY

Two 32-year-old males developed symptomatic PFCs after acute pancreatitis and came to our hospital for further treatment. One patient suffered from intermittent abdominal pain and vomiting, and computed tomography (CT) imaging showed an encapsulated cyst 7.93 cm × 6.13 cm in size. The other patient complained of a mass inside the abdomen, which gradually became enlarged. Gastric varices around the ideal puncture site were detected by EUS when we evaluated the possibility of endoscopic drainage in both patients. Interventional embolization was recommended as the first procedure to decrease the risk of bleeding. After that, EUS-guided transluminal drainage was successfully conducted, without vascular rupture. No postoperative complications occurred during hospitalization, and no recurrence was detected at the last follow-up CT scan performed at 1 mo.

CONCLUSION

Interventional embolization is a safe, preoperative procedure that is performed before EUS-guided drainage in PFC patients with gastric varices or at high risk of bleeding.

Indian College of Radiology and Imaging Consensus Guidelines on Interventions in Pancreatitis

Acute pancreatitis (AP) is one of the common gastrointestinal conditions presenting as medical emergency. Clinically, the severity of AP ranges from mild to severe. Mild AP has a favorable outcome. Patients with moderately severe and severe AP, on the other hand, require hospitalization and considerable utilization of health care resources. These patients require a multidisciplinary management. Pancreatic fluid collections (PFCs) and arterial bleeding are the most important local complications of pancreatitis. PFCs may require drainage when infected or symptomatic. PFCs are drained endoscopically or percutaneously, based on the timing and the location of collection. Both the techniques are complementary, and many patients may undergo dual modality treatment. Percutaneous catheter drainage (PCD) remains the most extensively utilized method for drainage in patients with AP and necrotic PFCs. Besides being effective as a standalone treatment in a significant proportion of these patients, PCD also provides an access for percutaneous endoscopic necrosectomy and minimally invasive necrosectomy. Endovascular embolization is the mainstay of management of arterial complications in patients with AP and chronic pancreatitis. The purpose of the present guideline is to provide evidence-based recommendations for the percutaneous management of complications of pancreatitis.

Imaging-Guided Percutaneous Puncture and Embolization of Visceral Pseudoaneurysms: Feasibility and Outcomes

Visceral artery pseudoaneurysms (VAPAs) are the most frequently diagnosed pseudoaneurysms (PSAs). PSAs can be asymptomatic or symptomatic. The aim of our study was to evaluate the safety and effectiveness of percutaneous embolization of VAPAs performed on patients with an unfeasible trans-arterial approach. Fifteen patients with fifteen visceral PSAs, with a median dimension of 21 mm (IQR 20–24 mm), were retrospectively analyzed. No patients were suitable for trans-arterial catheterization and therefore a percutaneous approach was chosen. During percutaneous treatments, two embolic agents were used, either N-butyl cyanoacrylate (NBCA) (Glubran II, GEM Milan, Italy) mixed with Lipiodol (Lipiodol, Guerbet, France) or thrombin. The outcomes of this study were technical success, primary clinical success, and secondary clinical success. In our population the 15 PSA were located as follows: 2 in the left gastric artery, 1 in the right gastric artery, 3 in the right hepatic artery, 2 in a jejunal artery, 1 in left colic artery branch, 1 in a right colic artery branch, 1 in the gastroepiploic artery, 1 in the dorsal pancreatic artery, 1 in an ileocolic artery branch, 1 in an iliac artery branch, and 1 in a sigmoid artery branch. 80% of PSAs (12/15) were treated with a NBCA:lipiodol mixture and 20% of PSAs (3/15) were treated with thrombin. Technical, primary, and secondary clinical successes were obtained in 100% of the cases. No harmful or life-threatening complications were observed. Minor complications were registered in 26.6% (4/15) of the patients. Percutaneous embolization of visceral PSA is a safe and effective treatment and should be considered as an option when the endovascular approach is unsuccessful or unfeasible.

Persistent Anemia in the Setting of a Rare Pancreatic Pseudoaneurysm

Introduction. Pancreatic pseudoaneurysm is a rare but potentially fatal complication that can follow pancreatitis. While early detection is critical to preventing poor long-term outcomes, clinical features vary significantly. Most often, abdominal pain is the presenting complaint, but this can be complicated as classic symptoms of pancreatitis also present with abdominal pain. Herein, we present a patient with an acute on chronic gastrointestinal bleed that was finally attributed to a pancreatic pseudoaneurysm. Case Presentation. The patient was a 56-year-old male with a past medical history significant for epilepsy, alcohol abuse, and hypertension who presented as a transfer from an outside facility for a gastrointestinal bleed. Prior to presentation, the patient reported rectal bleeding over the prior 1.5 months but had not sought care until bleeding increased along with increased abdominal pain. The patient's hemoglobin was 6.3 at presentation of the outside facility and received a total of four units of packed red blood cells (PRBCs) prior to arrival. After arrival, persistent bleeding was noted, and an additional 2 units of PRBCs were transfused. A computed tomography angiography (CTA) of the abdomen was obtained to identify the source for embolization. This, however, revealed a 4 × 4 × 3.5 cm intrinsically dense or enhanced mass of the pancreatic head. Discussion. Pancreatic pseudoaneurysm is a rare but potentially fatal complication that can follow pancreatitis. In chronic pancreatitis patients who underwent imaging incidence is estimated to be up to 10%. Treatment is difficult, and coil embolization is often used, though this can lead to splenectomy due to splenic ischemia. Stent grafts can be used in the surrounding arteries to maintain the integrity of viscera but carry risk of stent-related thrombosis. Further research is needed on the optimal management of this potentially lethal complication of pancreatitis.

Efficacy of endovascular embolization of arterial pseudoaneurysms in pancreatitis: A systematic review and meta-analysis

BACKGROUND

There is a significant variability in the reported outcomes following endovascular embolization of arterial pseudoaneurysms in pancreatitis. The objective of this systematic review and meta-analysis is to evaluate the efficacy of endovascular embolization of pancreatitis-related pseudoaneurysms.

METHODS

Searches of MEDLINE, EMBASE, and SCOPUS databases were performed through July 1, 2019 in accordance with PRISMA guidelines. All studies with ≥10 patients reporting technical success, clinical success, complications, and mortality were included. Generalized linear mixed method with random effects model was used for assessing pooled incidence rates and corresponding 95% confidence intervals (CIs).

RESULTS

A total of 29 studies (n = 840 with 638 pseudoaneurysms) were included. The pooled incidence rates of pseudoaneurysms in acute and chronic pancreatitis were 0.05% and 0.03%, respectively (odds ratio, 0.91, 95% CI-0.24-3.43). The most common site of pseudoaneurysm was splenic artery (37.7%). The most common embolization agent was coil (n = 415). The follow up period was 54.7 months (range, 21 days to 40.5 months). Pooled technical success rate was 97% (95% CI-92-99%, I² 83%). Clinical success rates at ≤3 months, 3-12 months, and >12 months were 82% (95% CI-70-90%, I² 42%), 86% (95% CI-75-92%, I² 44%), and 88% (95% CI-83-91%, I² 0%), respectively. There was no significant difference in the technical or clinical success between acute and chronic pancreatitis on subgroup analysis. Mortality was lower in chronic pancreatitis (OR 4.27 (95% CI 1.35-13.53, I² 0%)). Splenic infarction was the most common complication (n = 47).

CONCLUSION

Endovascular embolization is associated with a high technical and clinical success.

Splenic Artery Pseudoaneurysm in Chronic Pancreatitis Causing Obstructive Jaundice: Endovascular Management

BACKGROUND

Splenic artery pseudoaneurysm (SAP) around the pancreatic head causing obstructive jaundice is an extremely rare complication but can be life threatening once occurs. This case report is to raise awareness of this catastrophic complication and share our experience of successful endovascular management.

METHODS

A 47-year-old male with a history of chronic pancreatitis clinically presented with epigastric pain and jaundice. Proximal SAP complicated with obstructive jaundice was confirmed by laboratory and imaging investigations. The SAP was successfully treated by transarterial coil embolization, and the jaundice subsequently improved.

RESULTS

Abdominal contrast-enhanced computed tomography 11 months after embolization showed complete occlusion and reduction in the volume of the SAP as well as normal biliary tract.

CONCLUSIONS

SAP complicated with obstructive jaundice should be managed timeously and aggressively once diagnosed, given its potential adverse consequences. Transarterial embolization using the isolation technique may be a safe and effective strategy for treating this disease.

Duodenal Necrosis Associated with a Threatened Ruptured Gastroduodenal Artery Pseudoaneurysm Complicated by Chronic Pancreatitis: Case Report

Visceral artery pseudoaneurysm (PSA) complicated by pancreatitis is a relatively rare and potentially life-threatening condition. The formation of pancreatic PSA is mainly attributed to continuous inflammation response, which induces the enzymatic autodigestion of the adjacent artery wall. The spleen artery is the most affected vessel, and other vessels such as gastroduodenal artery (GDA) and pancreaticoduodenal artery are usually involved. The treatment options for pancreatic PSA include conservative therapy, open surgery (OS), and endovascular procedure. Currently, no broad consensus on the indications for pancreatic PSA treatment is available because of the rarity of the disease. We report an urgent case of a threatened ruptured GDA PSA with duodenal necrosis complicated by chronic pancreatitis that has been treated successfully with OS. The treatment choice, puzzles, and reflections of this case were all discussed in this paper.

Elective Embolization of Splenic Artery Aneurysms with an Ethylene Vinyl Alcohol Copolymer Agent (Squid) and Detachable Coils

PURPOSE

To report the safety and efficacy of the embolization of splenic artery aneurysms (SAAs) with coils plus ethylene vinyl alcohol copolymer (EVOH) agent.

MATERIALS AND METHODS

A single-center retrospective study was conducted from 2016 to 2019 to collect SAAs. Twelve asymptomatic patients (mean age, 59 years) with 15 SAAs (mean size, 23.6 mm; size range, 15-40 mm) were treated with embolization. Embolization was performed with EVOH (Squid 8/34) and fibered detachable coils. Transfemoral embolization was performed with a microcatheter to achieve a splenic artery occlusion embolizing the SAA and its efferent and afferent branches. Follow-up was based on color Doppler ultrasound at 24 hours and on computed tomography (CT) angiography at 1 (n = 12) and 6 months (n = 12) after embolization. Mean number of coils and Squid vials used for each patient, major/minor complications, technical success, 30-day clinical success, cases of revascularization/reintervention, and mortality were assessed. Technical success was defined as complete exclusion of the aneurysmal segment and cessation of blood flow into the sac. Clinical success at 1 month was based on the absence of clinical symptoms and the exclusion of aneurysm revascularization on CT angiography.

RESULTS

The mean number of coils and Squid vials was 5.75 (standard deviation [SD], 1.58; range, 3-9) and 1.41 (SD, 0.49; range, 1-2), respectively. Both technical and 30-day clinical success were 100%, with no cases of aneurysm revascularization (CT angiography performed in all patients at 1 month and 6 months and in 3 patients at 24 months). No major complications or fatal events were recorded. In terms of minor complications, 2 cases of mild pancreatitis (transient amylases increase) and 1 case of focal splenic ischemia without clinical sequelae were recorded.

CONCLUSIONS

Embolization in SAAs using coils plus EVOH was safe and effective without SAA revascularization.

Giant Splenic Artery Pseudoaneurysms: Two Case Reports and Cumulative Review of the Literature

BACKGROUND

Giant splenic artery pseudoaneurysms (GSAPs) > 5 cm are a rare clinical entity. The aim of this study was to present our experience with 2 such patients successfully treated by coil embolization and surgery and review the pertinent literature.

METHODS

A 58-year-old woman and 57-year-old man with a history of chronic pancreatitis were diagnosed with GSAP based on computed tomography (CT) angiography. The first patient had a 6-cm pseudoaneurysm, which was successfully treated with transcatheter coil embolization using a sandwich exclusion method. The second patient had two 7-cm lesions, which were successfully treated with distal pancreatectomy and splenectomy.

RESULTS

Postembolization CT angiography at 12 months showed remaining calcified pseudocyst without evidence of pseudoaneurysm in the first patient. Both patients remained well and symptom-free at 12 months.

CONCLUSIONS

Combined with the experience of the previous literature, we believe that management of GSAP should be tailored for each individual case depending on the location and number of pseudoaneurysms, the underlying etiology, and the patient's hemodynamic status. Embolization should be considered as the first-line treatment for clinically stable patients with GSAP, whereas GSAPs with a pseudocyst are best treated with surgery.

Hepatic Artery Aneurysm in the Setting of Acute Pancreatitis and Giant Cell Arteritis

Visceral artery aneurysms are rare with an incidence of 0.1%-0.2%. Of these, 20% are hepatic artery aneurysms (HAAs). Despite the potential of remaining asymptomatic for long periods of time, the risk of rupture for HAAs is 20%-80%. Treatment includes operative management with open or endovascular techniques. HAA in the setting of pancreatitis has been reported in two prior cases outside of the United States. However, there have been no cases describing the association of HAA and giant cell arteritis (GCA). We present a rare case of an 80-year-old male with a history of GCA who was found to have developed HAA following an episode of acute pancreatitis that was repaired surgically with an open technique. To our knowledge, the association between HAA with acute pancreatitis and GCA has not been reported before.

Outcome of radiological interventions in pediatric gastrointestinal diseases: A large tertiary center experience

Background

Interventional radiology (IR) is an indispensable component of multidisciplinary care in various gastrointestinal (GI) diseases. The literature on safety and utility of IR is limited in children.

Objectives

In this study, we aim to analyze the outcomes of IR in various pediatric GI diseases.

Methods

The data of children (≤18 years) who underwent radiological interventions for GI disorders (2009-2017) were analyzed, retrospectively. The indications for interventions included vascular (Budd Chiari syndrome [BCS], pseudoaneurysm) and nonvascular (pancreatic fluid collections [PFCs], cholangitis and anastomotic biliary strictures). The outcomes of radiological interventions, including success and adverse events, were assessed.

Results

A total of 93 children (mean age 13.45 ± 4.09 years) underwent radiological interventions for vascular (chronic BCS = 14, pseudoaneurysm = 28) or nonvascular (PFCs = 33, hepaticojejunostomy strictures or leaks = 12, cholangitis = 6) indications. Of 33 children who underwent drainage of PFCs, clinical success was noticed in 32 children during a mean follow-up of 32.4 ± 21.66 months; 11 children with persistent external pancreatic fistula were managed with endoscopic pancreatic ductal stenting (8 children) and internalization of transgastric drain (3 children). In children who underwent hepatic vein or inferior vena cava stenting for BCS, mean stent patency was 78.57% during a follow-up of 24.1 ± 13.78 months. In children with pseudoaneurysms, angioembolization was successfully performed in 92.8% patients. Re-bleeding was noticed in two children, one of whom required reintervention. In children who underwent percutaneous transhepatic biliary drainage, resolution of anastomotic strictures was noticed in all during a follow-up of 36.1 ± 13.73 months.

Conclusion

Interventional radiology is safe and effective in the management of various pediatric GI diseases.

Quantification of the impact of interventional radiology in the management of acute pancreatitis

OBJECTIVES

Interventional radiology plays a central role in the management of complicated acute pancreatitis, contributing to image-guided drainages, treating haemorrhagic complications and maintaining the patency of the biliary tree. In addition, many of these patients require long-term venous access for antibiotics or parenteral feeding. The aim of this study was to evaluate the role and level of involvement of the interventional radiology in this sub-group of patients.

METHODS

This was a single-centre retrospective review of all admissions for acute pancreatitis over a 5-year period. Each case was assessed to determine whether radiological intervention was utilised.

RESULTS

Our review included 401 patients. A total of 18.7% (75/401) of patients required vascular access procedures and 18.4% (74/401) required image-guided drainage. A total of 1.2% (2/401) patients had embolisation procedures performed. The embolisation procedures were performed to treat a pseudoaneurysm that had formed. Overall, 20.9% (84/401) of patients were referred to the interventional radiology department for a procedure; a majority of these patients were referred for multiple procedures over the course of their admission. The patients in the 'severe pancreatitis' category had a total of 154 procedures performed, which was 65.5% of the total procedures. On average, the patients who underwent multiple interventional procedures tended to have a longer admission and more complex disease.

CONCLUSION

The diagnosis and treatment of complicated acute pancreatitis is heavily dependent on the interventional radiology department. A substantial proportion of patients with pancreatitis required radiological intervention as part of their management, the proportion of which increased significantly in complex disease.

Percutaneous puncture and embolisation for pancreatitis-related pseudoaneurysm: the feasibility of thrombin injection even in collection of fluid surrounding the pseudoaneurysm

Purpose

Pancreatitis-related pseudoaneurysm, a potentially life-threatening condition, is treated utilising endovascular management as a first choice and alternatively by percutaneous direct puncture of the aneurysm and embolisation.

Case report

A 50-year-old man with alcohol-induced necrotic pancreatitis underwent transcatheter arterial embolisation (TAE) for multiple pancreatic pseudoaneurysms. TAE failed in one enlarged aneurysm in the pancreatic body, and percutaneous direct needle puncture and coagulation using thrombin was planned. Precise puncture of the aneurysmal sac under fluoroscopy and computed tomographic (CT) guidance failed, but we could inject about 500 units of thrombin through the outer cannula into the collection of fluid surrounding the aneurysm. Compared to preoperative images, contrast-enhanced CT (CECT) showed shrinkage of the pseudoaneurysm without complications just after the procedure and its disappearance five days after the procedure.

Conclusions

Percutaneous direct puncture and embolisation is a feasible choice to treat pancreatic pseudoaneurysms, and injection of thrombin even into the collection of fluid surrounding the pseudoaneurysm can be a viable alternative, especially in cases in which precise puncture of the aneurysmal sac is difficult because of its size and location.

Arterial Pseudoaneurysm within a Pancreatic Pseudocyst

The formation of pancreatic pseudocysts and (pseudo-)aneurysms of intestinal vessels are rare but life-threatening complications in acute and chronic pancreatitis. Here we report the rare case of a patient suffering from chronic pancreatitis with an arterial pseudoaneurysm within a pancreatic pseudocyst and present its successful therapeutic management by angioembolization to prevent critical bleeding. A 67-year-old male with a history of chronic pancreatitis presented with severe acute abdominal pain and vomiting to the emergency department. Seven weeks prior to the present admission, a CT scan had displayed a pancreatic pseudocyst with a maximum diameter of 53 mm. A laboratory examination revealed an elevated white blood cell count (15.40 × 103/μL), as well as elevated serum lipase (191 U/L), bilirubin (1.48 mg/dL), and blood glucose (353 mg/dL) levels. Sonographically, the previously described pancreatic pseudocyst revealed a slightly increased maximum diameter of 65 mm and an inhomogeneous echo of the cystic content. A contrast-enhanced CT scan showed a further increase in maximum diameter to 70 mm of the known pseudocyst. Inside the pseudocyst, a pseudoaneurysm originating from the splenic artery with a maximum diameter of 41 mm was visualized. After interdisciplinary consultation, prophylactic coil embolization of the splenic artery was immediately performed. The pseudoaneurysm was shut off from blood supply by back-door/front-door occlusion employing 27 coils, resulting in complete exclusion of the pseudoaneurysm from the circulation. Pseudoaneurysms are a rare complication of acute and chronic pancreatitis which has been shown to be efficiently treated by coil embolization.