Clinical Imaging xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Clinical Imaging journal homepage: http://www.clinicalimaging.org
Case Report
Hepatic fat accumulation with sparing associated with portal vein duplication Dal Mo Yang ⁎, Hyun Cheol Kim, Sang Won Kim Department of Radiology, Kyung Hee University Hospital at Gangdong, 149, Sangil-Dong, Gangdong-Gu, Seoul, South Korea
a r t i c l e
i n f o
Article history: Received 30 September 2013 Received in revised form 16 January 2014 Accepted 25 January 2014 Available online xxxx Keywords: Portal vein duplication Hepatic fat accumulation Sparing of fatty liver CT
a b s t r a c t Duplication of the portal vein is a rare congenital anomaly. We experienced a case of duplication of the portal vein associated with hepatic fat accumulation with sparing. Fat accumulation was seen in the central portion of the liver, which was supplied by the portal vein coursing upward to the porta hepatis (Portal Vein 2), and sparing of fatty liver was seen in the peripheral portion of the liver, which was supplied by the portal vein entering the liver inferiorly (Portal Vein 1). © 2014 Elsevier Inc. All rights reserved.
1. Introduction The portal vein is normally formed by the junction of the splenic and superior mesenteric veins, posterior to the neck of the pancreas. The main portal vein divides into right and left portal veins at the porta hepatis. There are many kinds of congenital anomalies of the portal vein, such as congenital agenesis, hypoplasia, atresia, stenosis, and duplication [1]. Duplication of the portal vein is a rare congenital anomaly, where one portal vein is a continuation of the splenic vein and the other originates from the superior mesenteric vein [2]. Only a few cases with computed tomographic (CT) evidence of portal vein duplication have been reported in the literature [2–4]. We describe the CT findings of a patient with duplication of the portal vein. One portal vein entered the liver inferiorly (Portal Vein 1) and the other coursed upward to the porta hepatis (Portal Vein 2). In addition, fat accumulation was seen in the central portion of the liver supplied by Portal Vein 2, while sparing of fatty liver was seen in the peripheral portion of the liver, which is supplied by Portal Vein 1.
cholesterol, 223 mg/dl; and total bilirubin, 1.3 mg/dl), glucose level (183 mg/dl) and C-reactive protein level (15.4 mg/dl) were elevated. Abdominal CT was performed to evaluate potential injury of intraabdominal organ. Pre-contrast enhanced CT scans show fatty liver, which is represented by low attenuation of the liver (18 HU) compared with that of the spleen (42 HU), Segment 1–3 and central portion of Segment 4–8. The peripheral portions of the liver were spared of fatty infiltration (40 HU) (Fig. 1). On post-contrast enhanced CT scans, there was an anterior abdominal wall skin defect and fat accumulation along the subcutaneous fat and omental fat. No bowel injury was seen. We incidentally found a duplication of the portal vein, a rare congenital
2. Case report A 62-year-old man presented to the emergency department with abdominal pain and a laceration of abdominal wall by rebar after a fall. His vital signs were stable. Physical examination revealed a 1-cm laceration of the abdominal wall located 7 cm superior to the umbilicus. The patient had a normal complete blood cell count except for elevated white blood cell count of 13.4×103/ml. His serum liver enzyme levels (aspartate aminotransferase, 42 U/l; alanine aminotransferase, 48 U/l; ⁎ Corresponding author. Department of Radiology, Kyung Hee University Hospital at Gangdong, 149, Sangil-Dong, Gangdong-Gu, Seoul, South Korea. Tel.: +82 3 440 6183; fax: +82 2 440 6932. E-mail address: [email protected] (D.M. Yang).
}
Fig. 1. A 49-year-old man with duplication of the portal vein. On pre-contrast enhanced CT scan, the attenuation of the liver including S1, S3, and central portion of S 4–8 (18 HU) (star) is lesser than that of the spleen (42 HU). However, peripheral portion of the right hepatic lobe is spared of fatty liver (40 HU) (s).
0899-7071/$ – see front matter © 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.clinimag.2014.01.011
Please cite this article as: Yang DM, et al, Hepatic fat accumulation with sparing associated with portal vein duplication, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.01.011
2
D.M. Yang et al. / Clinical Imaging xxx (2014) xxx–xxx
}
}
Fig. 2. Post-contrast enhanced axial CT scans (A) and (B) and coronal volume-rendered image (C) show a superior mesenteric vein (small open arrow) and splenic vein join (large open arrow) to form a portal vein (arrowhead). The portal vein is divided into two at anterior portion of pancreatic head; one of portal vein enters the liver inferiorly and supplies peripheral portion of segment of 4, 5, 6, 7, 8 (Portal Vein 1) (thin arrows). Another portal vein courses upward to the porta hepatis and supplies segment 1, 2, 3 and central portion of segment 4, 5, 6, 7, 8 (Portal Vein 2) (thick arrow).
anomaly. The superior mesenteric vein and splenic vein joined to form the portal vein at the anterior portion of pancreatic head. Then, the portal vein divided into two branches. One portal vein entered the liver inferiorly and supplied peripheral portion of segment of 4, 5, 6, 7, 8 (Portal Vein 1) (Figs. 2, 3). Another portal vein coursed upward to the
Fig. 3. On arterial phase of coronal CT scans (A), (B), and (C), the splenic vein (large open arrow) and Portal Vein 1 (thin arrow) are enhanced, but the superior mesenteric vein (small open arrow) and Portal Vein 2 (arrowhead) are not enhanced yet. star=fat infiltration. s=sparing of fatty liver.
Please cite this article as: Yang DM, et al, Hepatic fat accumulation with sparing associated with portal vein duplication, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.01.011
D.M. Yang et al. / Clinical Imaging xxx (2014) xxx–xxx
porta hepatis and supplied segment 1, 2, 3 and central portion of segment 4, 5, 6, 7, 8 (Portal Vein 2) (Figs. 2, 3). The patient underwent laparoscopic exploration, and at surgery the omentum was found to be adherent to the falciform ligament, with bleeding from the omentum. The omentum and peritoneum were repaired. The patient had an uneventful postoperative course and was discharged. 3. Discussion Duplication of portal vein is a rare developmental anomaly. Usually two separate portal veins course upward to the porta hepatis [2–5]. The condition may be a cause of abdominal pain [2] and can give rise to portal hypertension and esophageal varices [5]. In our case, portal vein duplication was incidentally found. Although there was slight elevation of liver enzymes, no evidence of portal hypertension was noted. Our case showed some differences from previous reports of CT findings in portal vein duplication. First, in previous reports, the splenic vein and superior mesenteric vein entered the liver separately and merged within the liver [2]. In such a case, the two portal veins are seen as a continuation of the splenic vein and superior mesenteric vein individually. In contrast, in our patient, splenic vein and superior mesenteric vein joined to form portal vein at anterior to the pancreatic head. Second, usually two separate portal veins course upward to the porta hepatis [2–4]. In our patient, however, one of the portal vein had abnormal course, running transverse to the lower portion of segment 4 of liver and upward to the S7 and S8 (Portal Vein 1) (Fig. 1). Another portal vein coursed upward to the porta hepatis (Portal Vein 2). At the porta hepatis, Portal Vein 2 divided into left and right branches. The right branch supplied central portion of the right hepatic lobe, while Portal Vein 1 supplied the peripheral portion of the right hepatic lobe. These findings are explained from an embryologic viewpoint. The paired vitelline veins transport blood from yolk sac to the primitive sinus venosus. During the fourth to fifth weeks of embryonic life, there are three cross-communications between vitelline veins: cranial, middle, and caudal [1]. Cranial and caudal communications lie ventral to the gut, but middle communication lies dorsal to the gut. There is selective involution of the venous network, and the caudal part of the right vitelline vein and the cranial part of the left vitelline vein progressively obliterate, producing the portal vein. Our case can be explained by assuming that the cranial part of the left vitelline vein was not obliterated in the embryonic stage. Thus the cranial and caudal portions persisted and the middle communication atrophied, forming two portal veins at the cranial portion, one portal vein at the middle portion and splenic and superior mesenteric vein at the caudal portion [5]. In our case, fat accumulation was seen in the central portion of the liver, an area supplied by Portal Vein 2. In contrast, fatty infiltration was spared in the peripheral portion of the liver, which was supplied from the Portal Vein 1. Although it is uncertain why uneven fatty infiltration is
3
occurred, we suggest that it is related to the hemodynamics of portal, splenic and superior mesenteric vein. In our case, the splenic vein and Portal Vein 1 enhanced on arterial phase on CT, but the superior mesenteric vein and Portal Vein 2 were not enhanced yet (Fig. 2). Therefore, we believe the blood in Portal Vein 1 is supplied from the splenic vein, while the blood in Portal Vein 2 is supplied from the superior mesenteric vein. Thus the blood in Portal Vein 1 has lower dietary fat or fatty acids rather than Portal Vein 2 because the blood in the Portal Vein 1 is mainly supplied from the splenic vein. Hepatic fatty infiltration is characterized by the accumulation of triglycerides within cytoplasmic fat vacuoles of the hepatocytes. Hepatic fatty infiltration can be diagnosed when the attenuation of the spleen is 10 HU greater than that of the liver on unenhanced CT scanning [6]. Hepatic fatty sparing can occur when intrahepatic portal flow is reduced and the hepatocytes receive fewer triglycerides [7]. It can also occur due to an alteration of hemodynamics caused by an aberrant venous inflow into the liver or adjacent to a space occupying a hepatic lesion [8,9]. In our case, blood flow from the splenic vein into the peripheral portion of the liver associated with duplication of the portal vein may have caused decreased uptake of triglycerides, leading to a sparing of steatosis. Most hepatic fatty sparing occurs focally, usually at the posterior aspect of segments IV and V near the gallbladder fossa and porta hepatis, but confluent sparing hepatic lesions such as that seen in our case are rare [10,11]. In conclusion, a case of duplication of portal vein associated with hepatic fat accumulation with sparing was diagnosed on CT. Duplication of portal vein can be a cause of hepatic fat sparing. References [1] Corness JA, McHugh K, Roebuck DJ, Taylor AM. The portal vein in children: radiological review of congenital anomalies and acquired abnormalities. Pediatr Radiol 2006;36:87–96. [2] Dighe M, Vaidya S. Duplication of the portal vein-a rare congenital anomaly. BJR 2009;82:e32–4. [3] Ito K, Matsunaga N, Mitchell DG, et al. Imaging of congenital abnormalities of the portal venous system. AJR 1997;168:233–7. [4] Ozbulbul NI. Congenital and acquired abnormalities of the portal venous system: multidetector CT appearances. Diagn Interv Radiol 2011;17:135–42. [5] Snavely JG, Breakell ES. Fetal hemorrhage from esophageal varices due to malformations and congenital stenoses in the portal venous system. Am J Med 1954;16:459–64. [6] Kawamoto S, Soyer PA, Fishman EK, Bluemke DA. Nonneoplastic liver disease: evaluation with CT and MR imaging. Radiographics 1998;18:827–48. [7] Valls C, Iannacconne R, Alba E, et al. Fat in the liver: diagnosis and characterization. Eur Radiol 2006;16:2292–308. [8] Matsui O, Kadoya M, Takahashi S, et al. Focal sparing of segment IV in fatty livers shown by sonography and CT: correlation with aberrant gastric venous drainage. AJR 1995;164:1137–40. [9] Karcaaltincaba M, Akhan O. Imaging of hepatic steatosis and fatty sparing. Eur J Radiol 2007;61:33–43. [10] Soyer P, Devine N, Somveille E, Rebibo G, Rambert C, Scherrer A. Hepatic pseudolesion around the falciform ligament: prevalence on CT examination. Abdom Imaging 1996;21:324–8. [11] Vilgrain V, Ronot M, Abdel-Rehim M, et al. Hepatic steatosis: a major trap in liver imaging. Diagn Interv Imaging 2013;94:713–27.
Please cite this article as: Yang DM, et al, Hepatic fat accumulation with sparing associated with portal vein duplication, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.01.011
Contents lists available at ScienceDirect
Clinical Imaging journal homepage: http://www.clinicalimaging.org
Case Report
Hepatic fat accumulation with sparing associated with portal vein duplication Dal Mo Yang ⁎, Hyun Cheol Kim, Sang Won Kim Department of Radiology, Kyung Hee University Hospital at Gangdong, 149, Sangil-Dong, Gangdong-Gu, Seoul, South Korea
a r t i c l e
i n f o
Article history: Received 30 September 2013 Received in revised form 16 January 2014 Accepted 25 January 2014 Available online xxxx Keywords: Portal vein duplication Hepatic fat accumulation Sparing of fatty liver CT
a b s t r a c t Duplication of the portal vein is a rare congenital anomaly. We experienced a case of duplication of the portal vein associated with hepatic fat accumulation with sparing. Fat accumulation was seen in the central portion of the liver, which was supplied by the portal vein coursing upward to the porta hepatis (Portal Vein 2), and sparing of fatty liver was seen in the peripheral portion of the liver, which was supplied by the portal vein entering the liver inferiorly (Portal Vein 1). © 2014 Elsevier Inc. All rights reserved.
1. Introduction The portal vein is normally formed by the junction of the splenic and superior mesenteric veins, posterior to the neck of the pancreas. The main portal vein divides into right and left portal veins at the porta hepatis. There are many kinds of congenital anomalies of the portal vein, such as congenital agenesis, hypoplasia, atresia, stenosis, and duplication [1]. Duplication of the portal vein is a rare congenital anomaly, where one portal vein is a continuation of the splenic vein and the other originates from the superior mesenteric vein [2]. Only a few cases with computed tomographic (CT) evidence of portal vein duplication have been reported in the literature [2–4]. We describe the CT findings of a patient with duplication of the portal vein. One portal vein entered the liver inferiorly (Portal Vein 1) and the other coursed upward to the porta hepatis (Portal Vein 2). In addition, fat accumulation was seen in the central portion of the liver supplied by Portal Vein 2, while sparing of fatty liver was seen in the peripheral portion of the liver, which is supplied by Portal Vein 1.
cholesterol, 223 mg/dl; and total bilirubin, 1.3 mg/dl), glucose level (183 mg/dl) and C-reactive protein level (15.4 mg/dl) were elevated. Abdominal CT was performed to evaluate potential injury of intraabdominal organ. Pre-contrast enhanced CT scans show fatty liver, which is represented by low attenuation of the liver (18 HU) compared with that of the spleen (42 HU), Segment 1–3 and central portion of Segment 4–8. The peripheral portions of the liver were spared of fatty infiltration (40 HU) (Fig. 1). On post-contrast enhanced CT scans, there was an anterior abdominal wall skin defect and fat accumulation along the subcutaneous fat and omental fat. No bowel injury was seen. We incidentally found a duplication of the portal vein, a rare congenital
2. Case report A 62-year-old man presented to the emergency department with abdominal pain and a laceration of abdominal wall by rebar after a fall. His vital signs were stable. Physical examination revealed a 1-cm laceration of the abdominal wall located 7 cm superior to the umbilicus. The patient had a normal complete blood cell count except for elevated white blood cell count of 13.4×103/ml. His serum liver enzyme levels (aspartate aminotransferase, 42 U/l; alanine aminotransferase, 48 U/l; ⁎ Corresponding author. Department of Radiology, Kyung Hee University Hospital at Gangdong, 149, Sangil-Dong, Gangdong-Gu, Seoul, South Korea. Tel.: +82 3 440 6183; fax: +82 2 440 6932. E-mail address: [email protected] (D.M. Yang).
}
Fig. 1. A 49-year-old man with duplication of the portal vein. On pre-contrast enhanced CT scan, the attenuation of the liver including S1, S3, and central portion of S 4–8 (18 HU) (star) is lesser than that of the spleen (42 HU). However, peripheral portion of the right hepatic lobe is spared of fatty liver (40 HU) (s).
0899-7071/$ – see front matter © 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.clinimag.2014.01.011
Please cite this article as: Yang DM, et al, Hepatic fat accumulation with sparing associated with portal vein duplication, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.01.011
2
D.M. Yang et al. / Clinical Imaging xxx (2014) xxx–xxx
}
}
Fig. 2. Post-contrast enhanced axial CT scans (A) and (B) and coronal volume-rendered image (C) show a superior mesenteric vein (small open arrow) and splenic vein join (large open arrow) to form a portal vein (arrowhead). The portal vein is divided into two at anterior portion of pancreatic head; one of portal vein enters the liver inferiorly and supplies peripheral portion of segment of 4, 5, 6, 7, 8 (Portal Vein 1) (thin arrows). Another portal vein courses upward to the porta hepatis and supplies segment 1, 2, 3 and central portion of segment 4, 5, 6, 7, 8 (Portal Vein 2) (thick arrow).
anomaly. The superior mesenteric vein and splenic vein joined to form the portal vein at the anterior portion of pancreatic head. Then, the portal vein divided into two branches. One portal vein entered the liver inferiorly and supplied peripheral portion of segment of 4, 5, 6, 7, 8 (Portal Vein 1) (Figs. 2, 3). Another portal vein coursed upward to the
Fig. 3. On arterial phase of coronal CT scans (A), (B), and (C), the splenic vein (large open arrow) and Portal Vein 1 (thin arrow) are enhanced, but the superior mesenteric vein (small open arrow) and Portal Vein 2 (arrowhead) are not enhanced yet. star=fat infiltration. s=sparing of fatty liver.
Please cite this article as: Yang DM, et al, Hepatic fat accumulation with sparing associated with portal vein duplication, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.01.011
D.M. Yang et al. / Clinical Imaging xxx (2014) xxx–xxx
porta hepatis and supplied segment 1, 2, 3 and central portion of segment 4, 5, 6, 7, 8 (Portal Vein 2) (Figs. 2, 3). The patient underwent laparoscopic exploration, and at surgery the omentum was found to be adherent to the falciform ligament, with bleeding from the omentum. The omentum and peritoneum were repaired. The patient had an uneventful postoperative course and was discharged. 3. Discussion Duplication of portal vein is a rare developmental anomaly. Usually two separate portal veins course upward to the porta hepatis [2–5]. The condition may be a cause of abdominal pain [2] and can give rise to portal hypertension and esophageal varices [5]. In our case, portal vein duplication was incidentally found. Although there was slight elevation of liver enzymes, no evidence of portal hypertension was noted. Our case showed some differences from previous reports of CT findings in portal vein duplication. First, in previous reports, the splenic vein and superior mesenteric vein entered the liver separately and merged within the liver [2]. In such a case, the two portal veins are seen as a continuation of the splenic vein and superior mesenteric vein individually. In contrast, in our patient, splenic vein and superior mesenteric vein joined to form portal vein at anterior to the pancreatic head. Second, usually two separate portal veins course upward to the porta hepatis [2–4]. In our patient, however, one of the portal vein had abnormal course, running transverse to the lower portion of segment 4 of liver and upward to the S7 and S8 (Portal Vein 1) (Fig. 1). Another portal vein coursed upward to the porta hepatis (Portal Vein 2). At the porta hepatis, Portal Vein 2 divided into left and right branches. The right branch supplied central portion of the right hepatic lobe, while Portal Vein 1 supplied the peripheral portion of the right hepatic lobe. These findings are explained from an embryologic viewpoint. The paired vitelline veins transport blood from yolk sac to the primitive sinus venosus. During the fourth to fifth weeks of embryonic life, there are three cross-communications between vitelline veins: cranial, middle, and caudal [1]. Cranial and caudal communications lie ventral to the gut, but middle communication lies dorsal to the gut. There is selective involution of the venous network, and the caudal part of the right vitelline vein and the cranial part of the left vitelline vein progressively obliterate, producing the portal vein. Our case can be explained by assuming that the cranial part of the left vitelline vein was not obliterated in the embryonic stage. Thus the cranial and caudal portions persisted and the middle communication atrophied, forming two portal veins at the cranial portion, one portal vein at the middle portion and splenic and superior mesenteric vein at the caudal portion [5]. In our case, fat accumulation was seen in the central portion of the liver, an area supplied by Portal Vein 2. In contrast, fatty infiltration was spared in the peripheral portion of the liver, which was supplied from the Portal Vein 1. Although it is uncertain why uneven fatty infiltration is
3
occurred, we suggest that it is related to the hemodynamics of portal, splenic and superior mesenteric vein. In our case, the splenic vein and Portal Vein 1 enhanced on arterial phase on CT, but the superior mesenteric vein and Portal Vein 2 were not enhanced yet (Fig. 2). Therefore, we believe the blood in Portal Vein 1 is supplied from the splenic vein, while the blood in Portal Vein 2 is supplied from the superior mesenteric vein. Thus the blood in Portal Vein 1 has lower dietary fat or fatty acids rather than Portal Vein 2 because the blood in the Portal Vein 1 is mainly supplied from the splenic vein. Hepatic fatty infiltration is characterized by the accumulation of triglycerides within cytoplasmic fat vacuoles of the hepatocytes. Hepatic fatty infiltration can be diagnosed when the attenuation of the spleen is 10 HU greater than that of the liver on unenhanced CT scanning [6]. Hepatic fatty sparing can occur when intrahepatic portal flow is reduced and the hepatocytes receive fewer triglycerides [7]. It can also occur due to an alteration of hemodynamics caused by an aberrant venous inflow into the liver or adjacent to a space occupying a hepatic lesion [8,9]. In our case, blood flow from the splenic vein into the peripheral portion of the liver associated with duplication of the portal vein may have caused decreased uptake of triglycerides, leading to a sparing of steatosis. Most hepatic fatty sparing occurs focally, usually at the posterior aspect of segments IV and V near the gallbladder fossa and porta hepatis, but confluent sparing hepatic lesions such as that seen in our case are rare [10,11]. In conclusion, a case of duplication of portal vein associated with hepatic fat accumulation with sparing was diagnosed on CT. Duplication of portal vein can be a cause of hepatic fat sparing. References [1] Corness JA, McHugh K, Roebuck DJ, Taylor AM. The portal vein in children: radiological review of congenital anomalies and acquired abnormalities. Pediatr Radiol 2006;36:87–96. [2] Dighe M, Vaidya S. Duplication of the portal vein-a rare congenital anomaly. BJR 2009;82:e32–4. [3] Ito K, Matsunaga N, Mitchell DG, et al. Imaging of congenital abnormalities of the portal venous system. AJR 1997;168:233–7. [4] Ozbulbul NI. Congenital and acquired abnormalities of the portal venous system: multidetector CT appearances. Diagn Interv Radiol 2011;17:135–42. [5] Snavely JG, Breakell ES. Fetal hemorrhage from esophageal varices due to malformations and congenital stenoses in the portal venous system. Am J Med 1954;16:459–64. [6] Kawamoto S, Soyer PA, Fishman EK, Bluemke DA. Nonneoplastic liver disease: evaluation with CT and MR imaging. Radiographics 1998;18:827–48. [7] Valls C, Iannacconne R, Alba E, et al. Fat in the liver: diagnosis and characterization. Eur Radiol 2006;16:2292–308. [8] Matsui O, Kadoya M, Takahashi S, et al. Focal sparing of segment IV in fatty livers shown by sonography and CT: correlation with aberrant gastric venous drainage. AJR 1995;164:1137–40. [9] Karcaaltincaba M, Akhan O. Imaging of hepatic steatosis and fatty sparing. Eur J Radiol 2007;61:33–43. [10] Soyer P, Devine N, Somveille E, Rebibo G, Rambert C, Scherrer A. Hepatic pseudolesion around the falciform ligament: prevalence on CT examination. Abdom Imaging 1996;21:324–8. [11] Vilgrain V, Ronot M, Abdel-Rehim M, et al. Hepatic steatosis: a major trap in liver imaging. Diagn Interv Imaging 2013;94:713–27.
Please cite this article as: Yang DM, et al, Hepatic fat accumulation with sparing associated with portal vein duplication, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.01.011
