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Hepatic arterial pseudoaneurysm after percutaneous radiofrequency ablation for hepatocellular carcinoma
European Journal of Radiology Extra 57 (2006) 85–89
Hepatic arterial pseudoaneurysm after percutaneous radiofrequency ablation for hepatocellular carcinoma Young-sun Kim, Hyo Keun Lim ∗ , Hyunchul Rhim, Young Soo Do Department of Radiology and the Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, South Korea Received 22 September 2005; accepted 6 December 2005
Abstract Complications of radiofrequency (RF) ablation for hepatic tumor can be categorized into the direct mechanical injury caused by an electrode and the collateral thermal damage. We experienced two cases of hepatic arterial pseudoaneurysm after percutaneous RF ablation for hepatocellular carcinoma. In the first case, direct mechanical injury to the hepatic artery by a RF electrode was considered responsible for the complications, and this was likely coupled with additional thermal injury. The patient was successfully treated with percutaneous transarterial embolization. The complications of the second case were deemed to be caused by diffuse thermal injury only. Although this type of complication is rare, we should keep it in mind because it is potentially fatal. © 2005 Elsevier Ireland Ltd. All rights reserved. Keywords: Liver neoplasms; Therapeutic radiology; Radiofrequency (RF) ablation; Interventional procedures; Complications; Arteries; Therapeutic embolization
Radiofrequency (RF) ablation is known to be a relatively safe interventional procedure for the treatment of unresectable hepatic tumor. On the basis of three recent large series that evaluated the complications of RF ablation for hepatic tumor, its complication rates are acceptable, and they range from 2.2% to 3.1% in the major cases [1–3]. The spectrum of relatively common major complications is very broad, but they are attributable to either a direct electrode puncture or collateral thermal damage. Most of the hemorrhages that have been reported as complications of RF ablation were intraperitoneal or subcapsular instead of being intrahepatic [1–4], and we can infer they may be caused by blood oozing from the directly-injured hepatic capsule and parenchyma. We recently experienced two extremely unusual cases of hepatic arterial injury that were caused by RF ablation for hepatocellular carcinoma ∗ Corresponding author at: Department of Radiology and the Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Kangnam-ku, Seoul 135-710, South Korea. Fax: +82 2 3410 2559. E-mail address: [email protected] (H.K. Lim).
1571-4675/$ – see front matter © 2005 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrex.2005.12.004
(HCC), and these injuries might have been associated with a direct puncture of the vessel and the collateral thermal damage, respectively. Hepatic arterial pseudoaneurysm that is caused by a direct injury during transhepatic interventional procedures is known well; however, to the best of our knowledge, this is the first case report concerning hepatic arterial pseudoaneurysm as a complication of RF ablation, and it is unique especially considering the hyperthermic environment of this procedure instead of the presence of a mere mechanical injury.
1. Case report 1.1. Case 1 A 63-year-old woman was referred to our department for RF ablation of HCC. She had been suffered from liver cirrhosis (Child-Pugh class A) that was associated with a hepatitis C viral infection. She had no specific past medical or surgical history, including vasculitis. The mass was abutted to the posterior segmental branch of the right portal
86
Y.-s. Kim et al. / European Journal of Radiology Extra 57 (2006) 85–89
Fig. 1. A 63-year-old woman who was treated with RF ablation for HCC in segment VII of the liver. (a) The hepatic arterial phase CT taken immediately after RF ablation shows the complete coverage of the tumor by the ablation zone that is surrounded by transient hyperemia (arrows). (b) The 1-month follow-up CT scan demonstrates an intensely enhancing hepatic arterial pseudoaneurysm (arrow) in the confines of the ablation zone. (c) Color Doppler US shows a whirling color signal (yin-yang sign) (arrow) with a continuation from the adjacent artery (white arrowhead). Connection of the color signal to the presumed portal vein or the presence of arterioportal shunting is also noted (black arrowheads). (d) The hepatic arteriogram reveals a large pseudoaneurysm (arrow) from the posterosuperior segmental branch of the hepatic artery. Note the early draining portal vein (arrowhead) that is due to the arterioportal shunt. (e) Contrast-enhanced CT taken 1 month after embolization shows the microcoil (arrow) used for embolization and the disappearance of the previous pseudoaneurysm.
Y.-s. Kim et al. / European Journal of Radiology Extra 57 (2006) 85–89
vein in segment VII of the liver, and it measured 2.3 cm at its maximal dimension on abdominal ultrasonography (US). The findings on gadolinium-enhanced dynamic magnetic resonance imaging were compatible with the diagnosis of HCC. The serum alpha-fetoprotein level was slightly ele-
87
vated (20.8 ng/mL; normal range 0–8.1 ng/mL). She refused surgical resection and she wanted to undergo percutaneous RF ablation. Under local anesthesia and with administering intravenous conscious sedation, we treated the tumor with an internally
Fig. 2. A 62-year-old woman who underwent RF ablation for the treatment of two HCCs in segment VII of the liver. (a, b) The axial scan and the coronalreformatted CT images during the hepatic arterial phase that were obtained on the day of the procedure show that the normal hepatic artery (arrows) runs along the inferior border of the ablation zone. The electrode pathway in the center of the ablation zone (arrowheads) is separated from the hepatic artery. (c) The CT scan taken at the same level of (a) 1 month after the RF ablation shows a diffuse fusiform dilatation of the hepatic artery (arrow), which might have been caused by a diffuse thermal injury of the arterial wall. (d) The CT scan taken 4 months after RF ablation shows a change of the hepatic artery from the diffuse fusiform dilatation to a nodular aneurysmal dilatation (arrow).
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Y.-s. Kim et al. / European Journal of Radiology Extra 57 (2006) 85–89
cooled electrode that had a 3-cm active tip (Cool-tip, Valleylab, Boulder, CO) and we used a 200-W RF generator (Valleylab). The tip of the electrode was placed into the tumor via an intercostal approach under US-guidance, and the application of the RF energy was continued for 15 min. Her vital signs were stable. The contrast-enhanced computed tomography (CT) scan obtained one hour after RF ablation showed complete treatment without any complication (Fig. 1a). The 1-month follow-up CT scan demonstrated an oval, intensely enhancing lesion that measured 12 mm in diameter in the confines of the ablation zone during the hepatic arterial phase. The attenuation of the enhancing lesion was similar to that of the abdominal aorta. Neither residual unablated tumor nor new tumor was found (Fig. 1b). On color Doppler US examination, a new lesion was found; it was an aneurysmal dilatation of the hepatic artery that had a whirling flow pattern and it was connected to the adjacent portal vein, and this represented an arterioportal shunt (Fig. 1c). The neck of aneurysm was present in the vicinity of the presumed electrode pathway. There was neither hepatic nor peritoneal hemorrhage, and the patient had not complained of any symptom or sign of bleeding after RF ablation. To prevent the potential rupture of the pseudoaneurysm, percutaneous transarterial embolization was performed. The hepatic arteriogram revealed an arterial pseudoaneurysm that originated from a posterosuperior segmental branch of the hepatic artery with early opacification of the portal vein or there was arterioportal shunting (Fig. 1d). Four pieces of 3 cm long, 3 mm in diameter vascular embolization microcoil (Tornado, Cook, Bloomington, IN) were used for the embolization of both the proximal and distal segments of the affected vessel. Post-embolization angiography showed non-opacification of the lesion. Successful embolization was confirmed by the absence of contrast enhancement of the previous enhanced lesion on the CT scan obtained 1 month after embolization (Fig. 1e). 1.2. Case 2 A 62-year-old woman was referred to our department for RF ablation for HCC. She had hepatitis B-associated liver cirrhosis of Child-Pugh class A. On the gray-scale US images, two hypoechoic masses that measured 2 and 2.7 cm, respectively, were identified at the subcapsular portion of segment VII of the liver. Both tumors were compatible with HCC on the contrast-enhanced multiphase helical CT. The serum alpha-fetoprotein level was 18.7 ng/mL. Biopsy was not performed because the diagnosis of HCC was evident and clear. In this case, RF ablation was planned because of the patient’s poor hepatic functional reservoir (the indocyanine green 15min retention rate was 54%). RF ablation was performed with a similar protocol as was done in the case 1, and the same types of devices were used. For the smaller tumor, RF energy was applied for 12 min.
For the larger one, we adopted the overlapping technique and a total of two ablations were performed for 12 and 6 min, respectively. She complained of self-limited mild abdominal discomfort for several hours after the procedure, and this was regarded as a usual post-ablation symptom. Follow-up CT obtained on the same day of the procedure demonstrated successful treatment and we found no remarkable finding other than periablational hyperemia. The coronal reformatted images identified that the electrode pathway was separated by about 8 mm from the hepatic artery (Fig. 2a and b). One month after RF ablation, the contrast-enhanced CT scan obtained during the hepatic arterial phase demonstrated a fusiform aneurysmal dilatation of the hepatic artery that ran along the inferior margin of the ablation zone (Fig. 2c). This change in the hepatic artery was overlooked at the time of interpretation. The contrast-enhanced CT scan obtained 4 months after RF ablation disclosed a small aneurysmal dilatation of the hepatic artery that measured 6 mm in diameter (Fig. 2d). Color Doppler US examination confirmed the presence of a small pseudoaneurysm. Because she complained no specific symptom or sign related to the lesion and also because the pseudoaneurysm was relatively small, the physician and the patient wanted to wait and observe the lesion for a short period.
2. Discussion From April 1994 to June 2005, a total of 2122 hepatic tumors in 1366 patients were treated by 1782 sessions of RF ablation at our institution. However, we experienced only two cases of hepatic arterial pseudoaneurysm as a complication of the procedures and the incidence (by session) was just 0.11%. In three recent large series that evaluated the complications of RF ablation for hepatic tumor [1–3], there was no case of hepatic arterial pseudoaneurysm during the RF ablations that were done for 5779 hepatic tumors in 3771 patients. Pseudoaneurysm of the hepatic artery is unusual, but it is one of the most serious conditions that may cause acute life-threatening hemorrhage. Although silent cases have been reported, the risk of rupture is so high that it reached 44% according to one study [5]. However, this study encompassed both intrahepatic and extrahepatic arterial pseudoaneurysms. If the pseudoaneurysm is confined intrahepatically, the risk of rupture may be decreased [6]. There are various etiologies of hepatic arterial pseudoaneurysm. Yet trauma, especially of an iatrogenic cause, constitutes the majority of its causes. Hepatic arterial injury can occur after such surgery as laparoscopic cholecystectomy and orthotopic liver transplantation. Pseudoaneurysms in those cases usually occur extrahepatically and these types of lesions were frequently observed in the past [7]. Nowadays, the intrahepatic occurrence of pseudoaneurysm has been increasing as transhepatic interventional procedures such as percutaneous transhepatic biliary drainage and liver biopsy have
Y.-s. Kim et al. / European Journal of Radiology Extra 57 (2006) 85–89
become more popular [7]. Non-traumatic causes, although they are very uncommon, include liver abscess, cholangitis and mycotic infection [8–10]. As far as we know, this is the first report of hepatic arterial pseudoaneurysm caused by RF ablation or by other image-guided hyperthermic ablation therapies for hepatic tumor. We infer the pathogenetic mechanism of the arterial pseudoaneurysm is probably different in the two cases. In case 1, the lesion was considered to be initiated from a direct mechanical injury by the electrode, and then was affected by the heat which might destroy arterial elastic fibers and muscle cells, because the aneurysmal neck was located at the presumed electrode pathway and the initial manifestation on CT was typical for that of a traumatic pseudoaneurysm. However, the aneurysm in case 2 was deemed to be caused by thermal injury only, because its shape was fusiform and the pathway of the electrode was separate from the affected vessel. We think thermal injury should be included in the list of intrahepatic arterial pseudoaneurysm although it is rare. In conclusion, we experienced two cases of intrahepatic arterial pseudoaneurysm as rare complications of percutaneous RF ablation for HCC. Although we encounter this complication only rarely, we should keep its possibility in mind during the evaluation of the follow-up CT scan because this complication has a potential to cause catastrophe to the patients if it is overlooked.
89
References [1] Livraghi T, Solbiati L, Meloni MF, Gazelle GS, Halpern EF, Goldberg SN. Treatment of focal hepatic tumors with percutaneous radiofrequency ablation: complications encountered in a multicenter study. Radiology 2002;226:441–51. [2] Rhim H, Yoon KH, Lee JM, et al. Major complications after radiofrequency thermal ablation of hepatic tumors: spectrum of imaging findings. Radiographics 2003;23:123–36. [3] de Baere T, Risse O, Kuoch V, et al. Adverse events during radiofrequency treatment of 582 hepatic tumors. AJR Am J Roentgenol 2003;181:695–700. [4] Mulier S, Mulier P, Ni Y, et al. Complications of radiofrequency coagulation of liver tumours. Br J Surg 2002;89:1206–22. [5] Stanley JC, Zelenock GB. Splanchnic artery aneurysms. In: Rutherford RB, editor. Vascular surgery. Philadelphia: Saunders; 1989. p. 973–5. [6] Zironi G, Piscaglia F, Gaiani S, Masi L, Bolondi L. Intrahepatic artery pseudoaneurysm: a possible complication of blind thoracentesis. J Clin Ultrasound 1999;27:151–5. [7] Finley DS, Hinojosa MW, Paya M, Imagawa DK. Hepatic artery pseudoaneurysm: a report of seven cases and a review of the literature. Surg Today 2005;35:543–7. [8] Kim MD, Kim H, Kang SW, Jeong BG. Non-traumatic hepatic artery pseudoaneurysm associated with acute leukemia: a possible complication of pyogenic liver abscess. Abdom Imaging 2002;27:458–60. [9] Liu TT, Hou MC, Lin HC, Chang FY, Lee SD. Life-threatening hemobilia caused by hepatic artery pseudoaneurysm: a rare complication of chronic cholangitis. World J Gastroenterol 2003;9:2883–4. [10] Leonardi LS, Soares Jr C, Boin IF, Oliveira VC. Hemobilia after mycotic hepatic artery pseudoaneurysm after liver transplantation. Transplant Proc 2001;33:2580–2.
Hepatic arterial pseudoaneurysm after percutaneous radiofrequency ablation for hepatocellular carcinoma Young-sun Kim, Hyo Keun Lim ∗ , Hyunchul Rhim, Young Soo Do Department of Radiology and the Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, South Korea Received 22 September 2005; accepted 6 December 2005
Abstract Complications of radiofrequency (RF) ablation for hepatic tumor can be categorized into the direct mechanical injury caused by an electrode and the collateral thermal damage. We experienced two cases of hepatic arterial pseudoaneurysm after percutaneous RF ablation for hepatocellular carcinoma. In the first case, direct mechanical injury to the hepatic artery by a RF electrode was considered responsible for the complications, and this was likely coupled with additional thermal injury. The patient was successfully treated with percutaneous transarterial embolization. The complications of the second case were deemed to be caused by diffuse thermal injury only. Although this type of complication is rare, we should keep it in mind because it is potentially fatal. © 2005 Elsevier Ireland Ltd. All rights reserved. Keywords: Liver neoplasms; Therapeutic radiology; Radiofrequency (RF) ablation; Interventional procedures; Complications; Arteries; Therapeutic embolization
Radiofrequency (RF) ablation is known to be a relatively safe interventional procedure for the treatment of unresectable hepatic tumor. On the basis of three recent large series that evaluated the complications of RF ablation for hepatic tumor, its complication rates are acceptable, and they range from 2.2% to 3.1% in the major cases [1–3]. The spectrum of relatively common major complications is very broad, but they are attributable to either a direct electrode puncture or collateral thermal damage. Most of the hemorrhages that have been reported as complications of RF ablation were intraperitoneal or subcapsular instead of being intrahepatic [1–4], and we can infer they may be caused by blood oozing from the directly-injured hepatic capsule and parenchyma. We recently experienced two extremely unusual cases of hepatic arterial injury that were caused by RF ablation for hepatocellular carcinoma ∗ Corresponding author at: Department of Radiology and the Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Kangnam-ku, Seoul 135-710, South Korea. Fax: +82 2 3410 2559. E-mail address: [email protected] (H.K. Lim).
1571-4675/$ – see front matter © 2005 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrex.2005.12.004
(HCC), and these injuries might have been associated with a direct puncture of the vessel and the collateral thermal damage, respectively. Hepatic arterial pseudoaneurysm that is caused by a direct injury during transhepatic interventional procedures is known well; however, to the best of our knowledge, this is the first case report concerning hepatic arterial pseudoaneurysm as a complication of RF ablation, and it is unique especially considering the hyperthermic environment of this procedure instead of the presence of a mere mechanical injury.
1. Case report 1.1. Case 1 A 63-year-old woman was referred to our department for RF ablation of HCC. She had been suffered from liver cirrhosis (Child-Pugh class A) that was associated with a hepatitis C viral infection. She had no specific past medical or surgical history, including vasculitis. The mass was abutted to the posterior segmental branch of the right portal
86
Y.-s. Kim et al. / European Journal of Radiology Extra 57 (2006) 85–89
Fig. 1. A 63-year-old woman who was treated with RF ablation for HCC in segment VII of the liver. (a) The hepatic arterial phase CT taken immediately after RF ablation shows the complete coverage of the tumor by the ablation zone that is surrounded by transient hyperemia (arrows). (b) The 1-month follow-up CT scan demonstrates an intensely enhancing hepatic arterial pseudoaneurysm (arrow) in the confines of the ablation zone. (c) Color Doppler US shows a whirling color signal (yin-yang sign) (arrow) with a continuation from the adjacent artery (white arrowhead). Connection of the color signal to the presumed portal vein or the presence of arterioportal shunting is also noted (black arrowheads). (d) The hepatic arteriogram reveals a large pseudoaneurysm (arrow) from the posterosuperior segmental branch of the hepatic artery. Note the early draining portal vein (arrowhead) that is due to the arterioportal shunt. (e) Contrast-enhanced CT taken 1 month after embolization shows the microcoil (arrow) used for embolization and the disappearance of the previous pseudoaneurysm.
Y.-s. Kim et al. / European Journal of Radiology Extra 57 (2006) 85–89
vein in segment VII of the liver, and it measured 2.3 cm at its maximal dimension on abdominal ultrasonography (US). The findings on gadolinium-enhanced dynamic magnetic resonance imaging were compatible with the diagnosis of HCC. The serum alpha-fetoprotein level was slightly ele-
87
vated (20.8 ng/mL; normal range 0–8.1 ng/mL). She refused surgical resection and she wanted to undergo percutaneous RF ablation. Under local anesthesia and with administering intravenous conscious sedation, we treated the tumor with an internally
Fig. 2. A 62-year-old woman who underwent RF ablation for the treatment of two HCCs in segment VII of the liver. (a, b) The axial scan and the coronalreformatted CT images during the hepatic arterial phase that were obtained on the day of the procedure show that the normal hepatic artery (arrows) runs along the inferior border of the ablation zone. The electrode pathway in the center of the ablation zone (arrowheads) is separated from the hepatic artery. (c) The CT scan taken at the same level of (a) 1 month after the RF ablation shows a diffuse fusiform dilatation of the hepatic artery (arrow), which might have been caused by a diffuse thermal injury of the arterial wall. (d) The CT scan taken 4 months after RF ablation shows a change of the hepatic artery from the diffuse fusiform dilatation to a nodular aneurysmal dilatation (arrow).
88
Y.-s. Kim et al. / European Journal of Radiology Extra 57 (2006) 85–89
cooled electrode that had a 3-cm active tip (Cool-tip, Valleylab, Boulder, CO) and we used a 200-W RF generator (Valleylab). The tip of the electrode was placed into the tumor via an intercostal approach under US-guidance, and the application of the RF energy was continued for 15 min. Her vital signs were stable. The contrast-enhanced computed tomography (CT) scan obtained one hour after RF ablation showed complete treatment without any complication (Fig. 1a). The 1-month follow-up CT scan demonstrated an oval, intensely enhancing lesion that measured 12 mm in diameter in the confines of the ablation zone during the hepatic arterial phase. The attenuation of the enhancing lesion was similar to that of the abdominal aorta. Neither residual unablated tumor nor new tumor was found (Fig. 1b). On color Doppler US examination, a new lesion was found; it was an aneurysmal dilatation of the hepatic artery that had a whirling flow pattern and it was connected to the adjacent portal vein, and this represented an arterioportal shunt (Fig. 1c). The neck of aneurysm was present in the vicinity of the presumed electrode pathway. There was neither hepatic nor peritoneal hemorrhage, and the patient had not complained of any symptom or sign of bleeding after RF ablation. To prevent the potential rupture of the pseudoaneurysm, percutaneous transarterial embolization was performed. The hepatic arteriogram revealed an arterial pseudoaneurysm that originated from a posterosuperior segmental branch of the hepatic artery with early opacification of the portal vein or there was arterioportal shunting (Fig. 1d). Four pieces of 3 cm long, 3 mm in diameter vascular embolization microcoil (Tornado, Cook, Bloomington, IN) were used for the embolization of both the proximal and distal segments of the affected vessel. Post-embolization angiography showed non-opacification of the lesion. Successful embolization was confirmed by the absence of contrast enhancement of the previous enhanced lesion on the CT scan obtained 1 month after embolization (Fig. 1e). 1.2. Case 2 A 62-year-old woman was referred to our department for RF ablation for HCC. She had hepatitis B-associated liver cirrhosis of Child-Pugh class A. On the gray-scale US images, two hypoechoic masses that measured 2 and 2.7 cm, respectively, were identified at the subcapsular portion of segment VII of the liver. Both tumors were compatible with HCC on the contrast-enhanced multiphase helical CT. The serum alpha-fetoprotein level was 18.7 ng/mL. Biopsy was not performed because the diagnosis of HCC was evident and clear. In this case, RF ablation was planned because of the patient’s poor hepatic functional reservoir (the indocyanine green 15min retention rate was 54%). RF ablation was performed with a similar protocol as was done in the case 1, and the same types of devices were used. For the smaller tumor, RF energy was applied for 12 min.
For the larger one, we adopted the overlapping technique and a total of two ablations were performed for 12 and 6 min, respectively. She complained of self-limited mild abdominal discomfort for several hours after the procedure, and this was regarded as a usual post-ablation symptom. Follow-up CT obtained on the same day of the procedure demonstrated successful treatment and we found no remarkable finding other than periablational hyperemia. The coronal reformatted images identified that the electrode pathway was separated by about 8 mm from the hepatic artery (Fig. 2a and b). One month after RF ablation, the contrast-enhanced CT scan obtained during the hepatic arterial phase demonstrated a fusiform aneurysmal dilatation of the hepatic artery that ran along the inferior margin of the ablation zone (Fig. 2c). This change in the hepatic artery was overlooked at the time of interpretation. The contrast-enhanced CT scan obtained 4 months after RF ablation disclosed a small aneurysmal dilatation of the hepatic artery that measured 6 mm in diameter (Fig. 2d). Color Doppler US examination confirmed the presence of a small pseudoaneurysm. Because she complained no specific symptom or sign related to the lesion and also because the pseudoaneurysm was relatively small, the physician and the patient wanted to wait and observe the lesion for a short period.
2. Discussion From April 1994 to June 2005, a total of 2122 hepatic tumors in 1366 patients were treated by 1782 sessions of RF ablation at our institution. However, we experienced only two cases of hepatic arterial pseudoaneurysm as a complication of the procedures and the incidence (by session) was just 0.11%. In three recent large series that evaluated the complications of RF ablation for hepatic tumor [1–3], there was no case of hepatic arterial pseudoaneurysm during the RF ablations that were done for 5779 hepatic tumors in 3771 patients. Pseudoaneurysm of the hepatic artery is unusual, but it is one of the most serious conditions that may cause acute life-threatening hemorrhage. Although silent cases have been reported, the risk of rupture is so high that it reached 44% according to one study [5]. However, this study encompassed both intrahepatic and extrahepatic arterial pseudoaneurysms. If the pseudoaneurysm is confined intrahepatically, the risk of rupture may be decreased [6]. There are various etiologies of hepatic arterial pseudoaneurysm. Yet trauma, especially of an iatrogenic cause, constitutes the majority of its causes. Hepatic arterial injury can occur after such surgery as laparoscopic cholecystectomy and orthotopic liver transplantation. Pseudoaneurysms in those cases usually occur extrahepatically and these types of lesions were frequently observed in the past [7]. Nowadays, the intrahepatic occurrence of pseudoaneurysm has been increasing as transhepatic interventional procedures such as percutaneous transhepatic biliary drainage and liver biopsy have
Y.-s. Kim et al. / European Journal of Radiology Extra 57 (2006) 85–89
become more popular [7]. Non-traumatic causes, although they are very uncommon, include liver abscess, cholangitis and mycotic infection [8–10]. As far as we know, this is the first report of hepatic arterial pseudoaneurysm caused by RF ablation or by other image-guided hyperthermic ablation therapies for hepatic tumor. We infer the pathogenetic mechanism of the arterial pseudoaneurysm is probably different in the two cases. In case 1, the lesion was considered to be initiated from a direct mechanical injury by the electrode, and then was affected by the heat which might destroy arterial elastic fibers and muscle cells, because the aneurysmal neck was located at the presumed electrode pathway and the initial manifestation on CT was typical for that of a traumatic pseudoaneurysm. However, the aneurysm in case 2 was deemed to be caused by thermal injury only, because its shape was fusiform and the pathway of the electrode was separate from the affected vessel. We think thermal injury should be included in the list of intrahepatic arterial pseudoaneurysm although it is rare. In conclusion, we experienced two cases of intrahepatic arterial pseudoaneurysm as rare complications of percutaneous RF ablation for HCC. Although we encounter this complication only rarely, we should keep its possibility in mind during the evaluation of the follow-up CT scan because this complication has a potential to cause catastrophe to the patients if it is overlooked.
89
References [1] Livraghi T, Solbiati L, Meloni MF, Gazelle GS, Halpern EF, Goldberg SN. Treatment of focal hepatic tumors with percutaneous radiofrequency ablation: complications encountered in a multicenter study. Radiology 2002;226:441–51. [2] Rhim H, Yoon KH, Lee JM, et al. Major complications after radiofrequency thermal ablation of hepatic tumors: spectrum of imaging findings. Radiographics 2003;23:123–36. [3] de Baere T, Risse O, Kuoch V, et al. Adverse events during radiofrequency treatment of 582 hepatic tumors. AJR Am J Roentgenol 2003;181:695–700. [4] Mulier S, Mulier P, Ni Y, et al. Complications of radiofrequency coagulation of liver tumours. Br J Surg 2002;89:1206–22. [5] Stanley JC, Zelenock GB. Splanchnic artery aneurysms. In: Rutherford RB, editor. Vascular surgery. Philadelphia: Saunders; 1989. p. 973–5. [6] Zironi G, Piscaglia F, Gaiani S, Masi L, Bolondi L. Intrahepatic artery pseudoaneurysm: a possible complication of blind thoracentesis. J Clin Ultrasound 1999;27:151–5. [7] Finley DS, Hinojosa MW, Paya M, Imagawa DK. Hepatic artery pseudoaneurysm: a report of seven cases and a review of the literature. Surg Today 2005;35:543–7. [8] Kim MD, Kim H, Kang SW, Jeong BG. Non-traumatic hepatic artery pseudoaneurysm associated with acute leukemia: a possible complication of pyogenic liver abscess. Abdom Imaging 2002;27:458–60. [9] Liu TT, Hou MC, Lin HC, Chang FY, Lee SD. Life-threatening hemobilia caused by hepatic artery pseudoaneurysm: a rare complication of chronic cholangitis. World J Gastroenterol 2003;9:2883–4. [10] Leonardi LS, Soares Jr C, Boin IF, Oliveira VC. Hemobilia after mycotic hepatic artery pseudoaneurysm after liver transplantation. Transplant Proc 2001;33:2580–2.