Visceral and Peripheral Arterial Pseudoaneurysms

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1 Visceral and Peripheral rterial Pseudoaneurysms Vascular Imaging Pictorial Essay Downloaded from by on 05/01/18 from IP address Copyright RRS. For personal use only; all rights reserved Eijun Sueyoshi 1 Ichiro Sakamoto 1 Kazuaki Nakashima 1 Kazunori Minami 2 Kuniaki Hayashi 1 Sueyoshi E, Sakamoto I, Nakashima K, Minami K, Hayashi K Received September 5, 2004; accepted after revision November 15, Department of Radiology, Nagasaki University School of Medicine, Sakamoto, Nagasaki , Japan. ddress correspondence to E. Sueyoshi. 2 Department of Radiology, Nagasaki Municipal Hospital, 6-39 Shinchi-machi, Nagasaki , Japan. Visceral and Peripheral rterial Pseudoaneurysms OJECTIVE. Pseudoaneurysms are not rare, and various conditions can cause a pseudoaneurysm in all the cardiovascular systems. In this article, we discuss and show images of pseudoaneurysms of various arteries caused by various conditions. CONCLUSION. CT, MRI, sonography, and angiography may all be valuable in the imaging workup of pseudoaneurysms. Knowledge of the various appearances of pseudoaneurysms and of the proper management is essential to prevent a catastrophic outcome in cases of pseudoaneurysm. seudoaneurysms can be life-threatening due to rupture and bleeding. P Therefore, pseudoaneurysms are considered an emergency disease and need to be diagnosed accurately and quickly. lso, prompt treatment using surgical, medial, and endovascular techniques is essential [1]. Moreover, pseudoaneurysms are not rare, and various conditions can cause a pseudoaneurysm in all the cardiovascular systems [1]. It is important to know the imaging findings of various pseudoaneurysms. The terms pseudoaneurysm, false aneurysm, pulsatile hematoma, and communicating hematoma are synonymous and may be used interchangeably [1]. In this article, we use the term pseudoaneurysm. pseudoaneurysm is defined as a pulsating, encapsulated hematoma in communication with the lumen of a ruptured vessel (Fig. 1). ventricular pseudoaneurysm is a cardiac rupture contained and loculated by the pericardium, which forms its external wall [2] (Fig. 2). Pathologically, the wall of arterial pseudoaneurysm has been breached, and the external wall of the aneurysmal sac consists of outer arterial layers, perivascular tissue, blood clot, or layer of reactive fibrosis [3] (Fig. 1C). In this article, we discuss and show images of pseudoaneurysms of various arteries, excluding cerebral and cervical pseudoaneurysms, that are caused by various conditions. CT may be the first imaging technique that is performed for the diagnosis of pseudoaneurysm [4]. Most pseudoaneurysms are saccular in shape. If angiography or endovascular treatment is required promptly, radiologists should try to reduce the total dose of contrast medium. Large pseudoaneurysms can be detected easily on contrast-enhanced CT, whereas small lesions can be overlooked easily. In such cases, angiography is required [4]. ngiography allows confirmation of the site of the pseudoaneurysm and assessment of its suitability for immediate treatment with an interventional technique if needed. CT angiography, MRI (including MR angiography), and sonography combined with color Doppler study are sometimes used for the diagnosis of pseudoaneurysm [4]. However, MRI has not been as useful as CT angiography or sonography in the diagnosis of pseudoaneurysm because its use is limited by the poor clinical condition of patients. Sonography has been shown to improve the detection of pseudoaneurysm. lthough the ability to perform the examination at the bedside and its relative low cost may make sonography an ideal firstline examination, the ability to diagnose pseudoaneurysm using sonography may depend on the location of the lesion and the skill of the operator [4]. JR 2005; 185: X/05/ merican Roentgen Ray Society Diagnosis of Pseudoaneurysm comprehensive imaging strategy is required for patients with pseudoaneurysm. Treatment of Pseudoaneurysm In the past, early surgical repair was recommended for the treatment of almost all JR:185, September

2 Downloaded from by on 05/01/18 from IP address Copyright RRS. For personal use only; all rights reserved Fig year-old man with pseudoaneurysms in aorta after surgery for thoracic aortic aneurysm. and, Two years after surgery, contrast-enhanced CT images of thoracic aorta show pseudoaneurysms (arrows) at both anastomotic sites of graft. C, Surgery was performed again. Photomicrograph of specimen of pseudoaneurysm of aorta shows that its wall consists of thrombus (a) and reactive fibrosis (b). There is no native wall structure. (H and E, 40) C Fig year-old man with pseudoaneurysm of heart due to infarction. and, xial spin-echo () and cine () MR images show pseudoaneurysm (arrows) of left ventricle due to myocardial infarction of posterolateral wall. C, Photograph of intraoperative findings reveals myocardial defect (arrow) covered by pericardium (arrowheads). In this case, patch graft for myocardial defect was performed. C 742 JR:185, September 2005

3 Visceral and Peripheral rterial Pseudoaneurysms Fig year-old man with pseudoaneurysm caused by angiographic procedure (coronary artery angiography). Contrast-enhanced axial CT image shows pseudoaneurysm of right femoral artery (arrows) after angiography. Recently, pseudoaneurysm of femoral artery tends to be treated by interventional techniques such as compression therapies, thrombin injection, or both. However, surgery was selected in this case because of severe pain. Downloaded from by on 05/01/18 from IP address Copyright RRS. For personal use only; all rights reserved Fig year-old man with pseudoaneurysm caused by chemoembolization for multiple hepatocellular carcinomas., Two weeks after chemoembolization, unenhanced CT image shows multiple areas of iodized oil (Lipiodol, Guerbet) in tumors., Three months after, angiogram was obtained because recurrent tumors were suspected. ngiogram shows tiny pseudoaneurysms of hepatic arteries (arrows). These pseudoaneurysms were not detectable on CT (not shown). Chemoembolization damaged vessel wall. pseudoaneurysms [1]. Recently, endovascular techniques have been widely used for the treatment of pseudoaneurysms because these techniques are minimally invasive and have a high success rate and are associated with low mortality [4]. However, surgery is the first choice for the treatment of a pseudoaneurysm of the left ventricle [5] (Fig. 2). Infected pseudoaneurysms also require surgical treatment because they may expand rapidly, leading to rupture, or may produce septic emboli that are then released JR:185, September

4 Downloaded from by on 05/01/18 from IP address Copyright RRS. For personal use only; all rights reserved Fig year-old man with splenic pseudoaneurysm caused by blunt abdominal trauma due to motor vehicle crash., Contrast-enhanced CT image shows pseudoaneurysm in spleen (arrow)., Splenic angiogram shows pseudoaneurysm in spleen (arrow). Metallic coil embolization was performed. Fig year-old woman with mesenteric pseudoaneurysm caused by blunt abdominal trauma due to motor vehicle crash., Contrast-enhanced CT image shows pseudoaneurysm (arrow) and hematoma in mesenterium., ngiogram of superior mesenteric artery shows pseudoaneurysm (arrows). Pseudoaneurysm is relatively rare in mesenterium. into the distal circulation [6]. Medical treatment might be appropriate for the management of pseudoaneurysms that were stable in size during the follow-up period [1, 7]. However, frequent follow-up examination is needed, and further studies are required for medical treatment of pseudoaneurysms to become generally accepted. Endovascular techniques, placement of a metallic coil or stent-graft, are frequently used for the treatment of pseudoaneurysm. The success of treatment depends on excluding the pseudoaneurysm from the circulation. Ideally, a metallic coil or stent-graft is placed from the proximal and distal ends of the pseudoaneurysm to avoid collateral circulation. Filling of the aneurysmal sac with embolic material, especially metallic coils, should generally be avoided because this often causes expansion of the pseudoaneurysm and risks its rupture [1, 8]. In some cases, pseudoaneurysm cannot be treated by this ideal procedure because of the difficulty of the technique and the possibility of complications, such as organ ischemia. Causes of Pseudoaneurysm Iatrogenic Complication This group includes pseudoaneurysms due to various medical procedures such as surgery or angiography (Figs. 1, 3, and 4). The incidence of iatrogenic pseudoaneurysms has risen exponentially in recent years 744 JR:185, September 2005

5 Visceral and Peripheral rterial Pseudoaneurysms Downloaded from by on 05/01/18 from IP address Copyright RRS. For personal use only; all rights reserved Fig year-old man with thoracic aortic pseudoaneurysm caused by blunt trauma due to motor vehicle crash., Contrast-enhanced CT image shows pseudoaneurysm in aortic arch (arrow)., Thoracic aortogram shows pseudoaneurysm in region of aortic isthmus (arrow). This case is typical of thoracic aortic pseudoaneurysm caused by trauma. Surgery was performed. fter surgery, patient has been doing well. Fig year-old man with pseudoaneurysm caused by neurofibromatosis., Contrast-enhanced CT image shows large masses (neurofibromas) around sacrum and left buttock. Hematomas (arrows) are seen around tumor, but pseudoaneurysm is not detectable on CT., ngiogram of left internal iliac artery shows pseudoaneurysm (arrow) originating from left superior gluteal artery. [1]. Pseudoaneurysm formation in the femoral arteries (puncture site) is a relatively common complication of catheterization (Fig. 3). The reported incidence of postcatheterization pseudoaneurysm varies widely from 0.05% to 14%. Iatrogenic pseudoaneurysms are most commonly produced by catheterization, accounting for 70 80% of the incidence [1]. JR:185, September

6 Downloaded from by on 05/01/18 from IP address Copyright RRS. For personal use only; all rights reserved Trauma This group of pseudoaneurysms includes those caused by accidents, such as car crashes, or by blunt or penetrating trauma (Figs. 5 7). The patient sometimes has multiple injuries. Most pseudoaneurysms that result from penetrating or blunt traumas are caused by gunshot injuries, stabbing wounds, and motor vehicle crashes [9]. The exact incidence of traumatic pseudoaneurysms is difficult to ascertain, but traumatic aortic pseudoaneurysm is the second most common form of thoracic aortic aneurysm and is most common in young adults. C Fig year-old man with pseudoaneurysm caused by malignant lymphoma., Unenhanced CT image shows marked hepatosplenomegaly. fter CT examination, chemotherapy started., Seven days after, patient complained of severe abdominal pain. Unenhanced CT image shows spleen has rapidly decreased in size, and hematoma (arrows) is seen in spleen. C, Splenic angiogram shows pseudoaneurysm (arrow). This pseudoaneurysm is caused by erosion by lymphoma. D, Splenectomy was performed. Photomicrograph of specimen of spleen shows that lymphoma cells (arrows) invade arterial wall (arrowheads). This is not a site of pseudoaneurysm. (H and E, 10) Ninety percent of the thoracic aortic injuries occur in the region of the aortic isthmus. Shearing stress and bending stress are forces that frequently involve the aortic isthmus (Fig. 7). The treatment for traumatic aortic pseudoaneurysm is urgent surgical repair. Traumatic pseudoaneurysm of the abdominal aorta is rare. Most (79%) are caused by penetrating injury [9]. In the abdomen, the spleen is the most frequently injured solid parenchymal organ, followed by liver, kidney, gastrointestinal tract, and pancreas [9] (Fig. 5). Injury by Tumor Vessel injury by tumor is a relatively rare cause of pseudoaneurysm. oth benign and malignant tumors can cause pseudoaneurysm due to vessel erosion [10] (Figs. 8 and 9). Pseudoaneurysms that are caused by osteochondroma are relatively common. In patients with neurofibromatosis, pseudoaneurysms also have been reported. Pseudoaneurysms are caused by degenerative changes of the vessel wall or secondary erosion by adjacent tumor in patients with neurofibromatosis [10] (Fig. 8). D 746 JR:185, September 2005

7 Visceral and Peripheral rterial Pseudoaneurysms Downloaded from by on 05/01/18 from IP address Copyright RRS. For personal use only; all rights reserved Malignant tumor often causes life-threatening bleeding, and it may, although rarely, cause pseudoaneurysm. The incidence of pseudoaneurysm caused by malignant tumor is uncertain, but choriocarcinoma has been reported to account for approximately one quarter of neoplastic aneurysms [11]. Several cases of pseudoaneurysm associated with leukemia and lymphoma have been reported. Leukemic cells or lymphomas damage the arterial wall and cause the formation of a pseudoaneurysm [12] (Fig. 9). Fig year-old man with pseudoaneurysm caused by Salmonella infection in abdominal aorta., Contrast-enhanced CT image shows pseudoaneurysm (arrow) and abscess (arrowheads) around aorta., ortogram shows pseudoaneurysm (arrow). Usually, surgery is first choice of treatment for infected aneurysm. In this case, stent-graft placement was selected because this patient was a poor surgical candidate. lthough patient was placed on antibiotics during and after this procedure; he died of rupture of pseudoaneurysm. Fig year-old man with pseudoaneurysm caused by ehçet s syndrome in pulmonary artery., Chest radiograph shows nodule (arrows) near left hilum., Pulmonary arteriogram shows pseudoaneurysm of segmental branch of pulmonary artery (arrow). Patient died of rupture of this pseudoaneurysm. Infection Infection includes both primary vessel wall infection and infection secondary to adjacent focus (Fig. 10). It can occur in any vessels, but the incidence of infected (mycotic) pseudoaneurysm is uncertain [13]. Infection can cause both true aneurysms and pseudoaneurysms. However, pseudoaneurysms may be more frequent because infection can easily disrupt the arterial wall. The most common location of an infected aneurysm is the femoral artery, followed by the abdominal aorta. The incidence of infected aortic aneurysms is reported to be % of all aneurysms; they often lead to uncontrolled sepsis and catastrophic hemorrhage if not treated [13]. In infected aortic aneurysms, the hematogenous spread of infections into the vasa vasorum of the aortic wall is thought to be the most common pathogenesis, and the organisms that most commonly cause infected aortic aneurysm are Staphylococcus aureus and Salmonella [13]. JR:185, September

8 Fig year-old woman with severe abdominal pain and pseudoaneurysm caused by Takayasu s arteritis. Contrast-enhanced oblique coronal reformatted CT image shows large pseudoaneurysm in abdominal aorta. lthough emergency surgery was planned, this patient died of rupture of pseudoaneurysm. Downloaded from by on 05/01/18 from IP address Copyright RRS. For personal use only; all rights reserved Fig year-old man with pseudoaneurysm caused by pancreatitis., Contrast-enhanced axial CT image shows large pseudoaneurysm., Splenic angiogram shows pseudoaneurysm originating from splenic artery. Vasculitis and Inflammation Vasculitis includes both primary vasculitis and vasculitis secondary to adjacent inflammation. Primary vasculitis can be seen in systemic vasculitis, such as ehçet s syndrome, polyarteritis nodosa, systemic lupus erythematosus, giant cell arteritis, Takayasu s arteritis, and so on [14] (Figs. 11 and 12). s the vessels become inflamed, the elastic fibers of the media are destroyed, thus resulting in pseudoaneurysm formation [14]. Pseudoaneurysms caused by primary vasculitis are relatively rare, but many cases of pseudoaneurysm caused by ehçet s syndrome have been reported [14] (Fig. 11). The frequency of vascular involvement in ehçet s syndrome is estimated to range from 2% to 46%. Pseudoaneurysms are more common than arterial occlusions or stenoses, and pseudoaneurysm rupture is a major cause of death [14]. The aorta is the most frequently affected site of pseudoaneurysm, followed by pulmonary, femoral, subclavian, and popliteal arteries [14]. Vasculitis secondary to adjacent inflammation associated with pancreatitis is rather common (Fig. 13). The splenic artery, because of its contiguity with the pancreas, is the vessel most commonly involved in pancreatitis. However, virtually all the pancreatic and peripancreatic vessels and superior mesenteric artery can be involved [15]. The most serious complication of visceral artery pseudoaneurysms is hemorrhage, with a mortality rate of %. When visceral artery pseudoaneurysms are not treated, the 748 JR:185, September 2005

9 Visceral and Peripheral rterial Pseudoaneurysms Fig year-old woman with chest pain and pseudoaneurysm caused by penetrating atherosclerotic ulcer. and, Contrast-enhanced axial CT image () and coronal reformatted image () show large pseudoaneurysm in descending thoracic aorta (arrow). In this case, penetrating atherosclerotic ulcer may be cause of pseudoaneurysm. Surgery was performed. fter undergoing surgery, patient has been doing well. Downloaded from by on 05/01/18 from IP address Copyright RRS. For personal use only; all rights reserved mortality rate becomes significantly higher, increasing to 90% [15]. therosclerosis therosclerotic changes usually cause true aneurysms of the vessel. However, recent reports suggest that penetrating atherosclerotic ulcer can cause a pseudoaneurysm of the aorta (Fig. 14). Penetrating atherosclerotic ulcer is defined as an atheromatous plaque with an ulcer of the aortic wall. It most often occurs in elderly patients and typically involves the descending aorta. It can disrupt the internal elastic lamina and can cause aortic dissection, pseudoaneurysm, or rupture of aorta [16]. Infarction Infarction is a common cause of pseudoaneurysm of the left ventricle (Fig. 2). Rupture of the wall of the left ventricle is a catastrophic complication of myocardial infarction, occurring in approximately 4% of patients with infarcts and about 23% of those who have fatal infarct. Rarely, wall rupture is contained by overlying, adherent pericardium, thereby producing what has been termed pseudoaneurysm of the left ventricle [5]. Conclusion Pseudoaneurysms can occur in all vascular beds. CT, MRI, sonography, and angiography may all be valuable in the imaging workup of pseudoaneurysms. Prompt diagnosis and treatment of pseudoaneurysms are necessary to avoid the morbidity and mortality associated with hemorrhage and rupture. Treatment can involve surgical, medical, and endovascular methods. References 1. Franklin J, righam D, ogey WM, Powell CS. Treatment of iatrogenic false aneurysms. J m Coll Surg 2003; 197: Pugh M. Stedman s medical dictionary, 27th ed. altimore, MD: Williams & Wilkins, 1999: Schoen FJ, Cotran RS. lood vessels. In: Cotran RS, ed. Robbins pathologic basis of disease. Philadelphia, P: Saunders, 1999: Marshall MM, Muiesan P, Srinivasan P, et al. Hepatic artery pseudoaneurysms following liver transplantation: incidence, presenting features and management. Clin Radiol 2001; 56: [Erratum in Clin Radiol 2001; 56:785] 5. rown SL, Gropler RJ, Harris KM. Distinguishing left ventricular aneurysm from pseudoaneurysm: a review of the literature. Chest 1997; 111: Kato N, Hirano T, Ishida M, et al. cute and contained rupture of the descending thoracic aorta: treatment with endovascular stent grafts. J Vasc Surg 2003; 37: Schaub F, Theiss W, usch R, Heinz M, Paschalidis M, Schomig. Management of 219 consecutive cases of postcatheterization pseudoaneurysm. J m Coll Cardiol 1997; 30: Dasgupta R, Davies NJ, Williamson RCN, Jackson JE. Haemosuccus pancreaticus: treatment by arterial embolization. Clin Radiol 2002; 57: Feliciano DV, Mattox KL. Traumatic aneurysms. In: Rutherford R, ed. Vascular surgery. Philadelphia, P: Saunders, 1989: Smith L, Munschauer CE, Diamond N, Rivera F. Ruptured internal carotid aneurysm resulting from neurofibromatosis: treatment with intraluminal stent graft. J Vasc Surg 2000; 32: Yang DM, Yoon MH, Kim HS, Kim HS, Shin D. Interrenal pseudoaneurysms complicating renal choriocarcinoma metastases: treatment with coil embolization. Clin Imaging 2000; 24: Kim MD, Kim H, Kang SW, Jeong G. Nontraumatic hepatic artery pseudoaneurysm associated with acute leukemia: a possible complication of pyogenic liver abscess. bdom Imaging 2002; 27: Gomes MN, Choyke PL. Infected aneurysms of the aorta: CT diagnosis. J Cardiovasc Surg 1992; 33: Ko GY, yun JY, Choi G, et al. The vascular manifestations of ehçet disease: angiographic and CT findings. r J Radiol 2000; 73: Hama Y, Kaji T, Iwasaki Y, et al. Transcatheter embolization of a superior mesenteric artery pseudoaneurysm. cta Radiol 1999; 40: Macura KJ, Corl FM, Fishman EK, luemke D. Pathogenesis in acute aortic syndromes: aortic dissection, intramural hematoma, and penetrating atherosclerotic aortic ulcer. JR 2003; 181: JR:185, September