Ultrasound
Ultrasonographic Demonstration of Portal Vein Thrombosis 1 Christopher R. B. Merritt, M.D.
For screening patients suspected of having portal vein thrombosis, the ultrasound examination is simple to perform, noninvasive, and can be accomplished rapidly. Three patients were studied in whom ultrasound examination revealed portal vein thrombosis that was subsequently confirmed by angiography or surgery. Ultrasonic findings in a series of 100 randomly selected patients are summarized. INDEX TERMS: Gastrointestinal tract, hemorrhage. (Liver, biliary ultrasonography, 7[6].1298). Portal vein, abnormalities • Portal vein, ultrasound studies. Thrombosis, portal vein. (Vessels of GI system, ultrasonography, 9[5].1298) Radiology 133:425-427, November 1979
examination of the upper abdomen the extrahepatic portal vein and its major tributaries are constant vascular landmarks that are seen with a high degree of consistency. Abnormalities of the portal venous system that have been demonstrated with ultrasound include portal vein dilation secondary to portal hypertension (1), and extrahepatic portal vein obstruction (2). Ultrasound has also been used for the evaluation of portacaval shunts (3). We have studied three patients in whom ultrasonography revealed portal vein thrombosis which was subsequently confirmed by angiography or surgery. The ultrasonic findings consisted of direct visualization of thrombi within the lumen of the portal vein, obliteration of normal portal venous landmarks, and secondary signs of portal vein occlusion including dilation of splenic and mesenteric veins proximal to the point of occlusion.
I
N ULTRASONOGRAPHIC
CASE REPORTS CASE I: A 60-year-old woman presented with melena, anemia, and a long history of gastrointestinal bleeding. Endoscopy revealed a fresh clot in the stomach. Ultrasonic examination (Figs. 1, 2) revealed a conspicuous filling defect in the extrahepatic portal vein. The defect was reproduced on several scans and could be seen to partially occlude the main portal vein. Superior mesenteric angiography(Fig. 3) confirmed partial occlusion of the portal vein. Portal hypertension due to extrahepatic portal vein thrombosis was the probable cause of variceal bleeding; bleeding was controlled with medical management and the patient was discharged.
CASE II: A 69-year-old man with a presumptive diagnosis of postnecrotic cirrhosis with ascites, portal hypertension, and esophageal varices, was admitted with upper gastrointestinal bleeding. Endoscopy showed that the bleeding was caused by esophageal varices. Ultrasonic examination of the abdomen revealed dilation of the splenic and superior
1,2
Fig. 1. Longitudinal scan to the right of the midline reveals the liver (L) and inferior vena cava (IVC). The portal vein is partially occluded by a portal vein thrombus (PVT). Fig. 2. Transverse decubitus scan shows the portal vein as it enters the porta hepatis with lumen almost completely occluded liver; IVC inferior vena cava; Ao aorta; S spine. by a portal vein thrombus (PVT). L
=
1
=
=
=
From the Department of Radiology, Ochsner Medical Institutions, New Orleans, LA. Received Feb. 12, 1979; accepted May 12.
425
ds
426
CHRISTOPHER R.
B. MERRITT
November 1979
Fig. 4. Longitudinal midline scan reveals a dilated superior mesenteric vein (SMV) at the superior mesenteric-splenic vein confluence. The liver (L) and a portion of the aorta (Ao) are also seen. Additional longitudinal scans to the right of this plane failed to demonstrate the portal vein. Fig. 3. Venous phase of superior mesenteric angiogram reveals the opacification of the superior mesenteric vein. The portal vein (open arrows) contains a conspicuous filling defect due to a portal vein thrombus (solid arrows) which almost totally occludes the lumen of the extrahepatic portion of the portal vein.
mesenteric veins (Fig. 4), and the portal vein was not demonstrable. Angiography likewise failed to show the portal vein. Surgery was performed to control severe upper gastrointestinal bleeding and at this time the portal vein was found to be thrombosed, the splenic and mesenteric vessels were dilated, and the liver was small and cirrhotic. A mesocaval shunt was created and the patient has done well.
CASE III: A 38-year-old man was admitted who had recently been vomiting blood. Physical examination revealed evidence of anemia and splenomegaly. Endoscopy revealed moderately severe esophageal varices with normal stomach and duodenum. The patient was treated medically, but was readmitted three months later with recurrent upper gastrointestinal bleeding. Ultrasound at this time revealed a liver of normal size and moderate splenomegaly. Multiple views failed to demonstrate the normal portal venous structures (Figs. 5, 6), the superior mesenteric vein, or the splenic vein. At surgery the portal, splenic, and superior mesenteric veins were found to be completely occluded.
DISCUSSION
Although portal hypertension is most often caused by disease within the liver, portal vein thrombosis is the most important cause of prehepatic portal hypertension. The possibility of portal vein thrombosis must be considered in patients who present with bleeding from esophageal varices, in patients with intractable ascites, and in patients who have other signs of portal hypertension. In most cases of portal vein thrombosis the underlying etiology is not known. Specific causes of prehepatic portal vein occlusion, however, include tumor invasion of the portal vein, occlusion secondary to pancreatitis, and schistosomiasis. The clinical findings in prehepatic portal hypertension due to portal vein thrombosis include a small liver, dilation of nonthrombosed veins that drain into the portal system, and portasystemic collateral circulation. Splenoportography and arterioportography have been used to evaluate patients suspected of having portal vein
5,6
I Fig. 5. Transverse scan at the level of the porta hepatis (PH)shows no evidence of the normal portal venous landmarks. In healthy persons, the portal vein is a conspicuous structure at this level. L = liver; Sp = spleen; S = spine. Fig. 6· Transverse scan 2 cm caudal to Figure 5 also fails to reveal any normal portal venous landmarks. L = liver; Sp = spleen; S = spine; RK = right kidney; GB = gallbladder; PH = porta hepatis.
Vol. 133
427
DEMONSTRATION OF PORTAL VEIN THROMBOSIS
thrombosis, but although these procedures are accurate aids in diagnosing portal vein thrombosis and in demonstrating portasystemic collateral circulation, they entail risk and discomfort to the patient. In contrast, ultrasound is well suited as a screening test for patients suspected of having portal vein thrombosis because it is simple, noninvasive, and can be accomplished rapidly. Ultrasound is also useful in the initial evaluation of patients with bleeding varices and in differentiating patients with presinusoidal portal venous disease from those with more common forms of portal hypertension resulting from cirrhosis. The normal portal vein is conspicuous and readily identifiable on abdominal ultrasound examination. In my survey of 100 randomly selected examinations of the upper abdomen, the portal vein could be seen as it entered the porta hepatis in 97 %; as it crossed the inferior vena cava in 83 % ; and at the level of confluence of the splenic and superior mesenteric veins in 83 % . Failure to visualize the extrahepatic portal vein is usually due to overlying bowel gas but satisfactory visualization can often be obtained if the patient is rescanned at another time. Failure to demonstrate the normal portal vein and its major tributaries should raise the question of portal vein thrombosis. The
Ultrasound
important ultrasonic findings in patients with the latter include: (a) the presence of thrombi within the portal vein; (b) dilation of the splenic and superior mesenteric veins proximal to the point of portal vein occlusion; and (c) loss of normal portal venous landmarks. In most patients with portal vein thrombosis, each of these can readily be demonstrated with currently available gray-scale scanning and real-time equipment. ACKNOWLEDGMENT: Ms. Melissa Reiman, R.D.M.S., provided technical assistance in performing the ultrasound examinations. Christopher R. B. Merritt, M.D. Ochsner Clinic 1514 Jefferson Highway New Orleans, LA 70121
REFERENCES 1. Carlsen EN, Filly RA: Newer ultrasonographic anatomy in the upper abdomen: I. The portal and hepatic venous anatomy. J Clin Ultrasound 4:85-90, Apr 1976 2. Webb LJ, Berger LA, Sherlock S: Gray-scale ultrasonography of portal vein. Lancet 2:675-677, Oct 1977 3. Goldberg BB (ed): Abdominal Gray-Scale Ultrasonography.New York, Wiley, 1977, pp 87-94
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Ultrasonographic Demonstration of Portal Vein Thrombosis 1 Christopher R. B. Merritt, M.D.
For screening patients suspected of having portal vein thrombosis, the ultrasound examination is simple to perform, noninvasive, and can be accomplished rapidly. Three patients were studied in whom ultrasound examination revealed portal vein thrombosis that was subsequently confirmed by angiography or surgery. Ultrasonic findings in a series of 100 randomly selected patients are summarized. INDEX TERMS: Gastrointestinal tract, hemorrhage. (Liver, biliary ultrasonography, 7[6].1298). Portal vein, abnormalities • Portal vein, ultrasound studies. Thrombosis, portal vein. (Vessels of GI system, ultrasonography, 9[5].1298) Radiology 133:425-427, November 1979
examination of the upper abdomen the extrahepatic portal vein and its major tributaries are constant vascular landmarks that are seen with a high degree of consistency. Abnormalities of the portal venous system that have been demonstrated with ultrasound include portal vein dilation secondary to portal hypertension (1), and extrahepatic portal vein obstruction (2). Ultrasound has also been used for the evaluation of portacaval shunts (3). We have studied three patients in whom ultrasonography revealed portal vein thrombosis which was subsequently confirmed by angiography or surgery. The ultrasonic findings consisted of direct visualization of thrombi within the lumen of the portal vein, obliteration of normal portal venous landmarks, and secondary signs of portal vein occlusion including dilation of splenic and mesenteric veins proximal to the point of occlusion.
I
N ULTRASONOGRAPHIC
CASE REPORTS CASE I: A 60-year-old woman presented with melena, anemia, and a long history of gastrointestinal bleeding. Endoscopy revealed a fresh clot in the stomach. Ultrasonic examination (Figs. 1, 2) revealed a conspicuous filling defect in the extrahepatic portal vein. The defect was reproduced on several scans and could be seen to partially occlude the main portal vein. Superior mesenteric angiography(Fig. 3) confirmed partial occlusion of the portal vein. Portal hypertension due to extrahepatic portal vein thrombosis was the probable cause of variceal bleeding; bleeding was controlled with medical management and the patient was discharged.
CASE II: A 69-year-old man with a presumptive diagnosis of postnecrotic cirrhosis with ascites, portal hypertension, and esophageal varices, was admitted with upper gastrointestinal bleeding. Endoscopy showed that the bleeding was caused by esophageal varices. Ultrasonic examination of the abdomen revealed dilation of the splenic and superior
1,2
Fig. 1. Longitudinal scan to the right of the midline reveals the liver (L) and inferior vena cava (IVC). The portal vein is partially occluded by a portal vein thrombus (PVT). Fig. 2. Transverse decubitus scan shows the portal vein as it enters the porta hepatis with lumen almost completely occluded liver; IVC inferior vena cava; Ao aorta; S spine. by a portal vein thrombus (PVT). L
=
1
=
=
=
From the Department of Radiology, Ochsner Medical Institutions, New Orleans, LA. Received Feb. 12, 1979; accepted May 12.
425
ds
426
CHRISTOPHER R.
B. MERRITT
November 1979
Fig. 4. Longitudinal midline scan reveals a dilated superior mesenteric vein (SMV) at the superior mesenteric-splenic vein confluence. The liver (L) and a portion of the aorta (Ao) are also seen. Additional longitudinal scans to the right of this plane failed to demonstrate the portal vein. Fig. 3. Venous phase of superior mesenteric angiogram reveals the opacification of the superior mesenteric vein. The portal vein (open arrows) contains a conspicuous filling defect due to a portal vein thrombus (solid arrows) which almost totally occludes the lumen of the extrahepatic portion of the portal vein.
mesenteric veins (Fig. 4), and the portal vein was not demonstrable. Angiography likewise failed to show the portal vein. Surgery was performed to control severe upper gastrointestinal bleeding and at this time the portal vein was found to be thrombosed, the splenic and mesenteric vessels were dilated, and the liver was small and cirrhotic. A mesocaval shunt was created and the patient has done well.
CASE III: A 38-year-old man was admitted who had recently been vomiting blood. Physical examination revealed evidence of anemia and splenomegaly. Endoscopy revealed moderately severe esophageal varices with normal stomach and duodenum. The patient was treated medically, but was readmitted three months later with recurrent upper gastrointestinal bleeding. Ultrasound at this time revealed a liver of normal size and moderate splenomegaly. Multiple views failed to demonstrate the normal portal venous structures (Figs. 5, 6), the superior mesenteric vein, or the splenic vein. At surgery the portal, splenic, and superior mesenteric veins were found to be completely occluded.
DISCUSSION
Although portal hypertension is most often caused by disease within the liver, portal vein thrombosis is the most important cause of prehepatic portal hypertension. The possibility of portal vein thrombosis must be considered in patients who present with bleeding from esophageal varices, in patients with intractable ascites, and in patients who have other signs of portal hypertension. In most cases of portal vein thrombosis the underlying etiology is not known. Specific causes of prehepatic portal vein occlusion, however, include tumor invasion of the portal vein, occlusion secondary to pancreatitis, and schistosomiasis. The clinical findings in prehepatic portal hypertension due to portal vein thrombosis include a small liver, dilation of nonthrombosed veins that drain into the portal system, and portasystemic collateral circulation. Splenoportography and arterioportography have been used to evaluate patients suspected of having portal vein
5,6
I Fig. 5. Transverse scan at the level of the porta hepatis (PH)shows no evidence of the normal portal venous landmarks. In healthy persons, the portal vein is a conspicuous structure at this level. L = liver; Sp = spleen; S = spine. Fig. 6· Transverse scan 2 cm caudal to Figure 5 also fails to reveal any normal portal venous landmarks. L = liver; Sp = spleen; S = spine; RK = right kidney; GB = gallbladder; PH = porta hepatis.
Vol. 133
427
DEMONSTRATION OF PORTAL VEIN THROMBOSIS
thrombosis, but although these procedures are accurate aids in diagnosing portal vein thrombosis and in demonstrating portasystemic collateral circulation, they entail risk and discomfort to the patient. In contrast, ultrasound is well suited as a screening test for patients suspected of having portal vein thrombosis because it is simple, noninvasive, and can be accomplished rapidly. Ultrasound is also useful in the initial evaluation of patients with bleeding varices and in differentiating patients with presinusoidal portal venous disease from those with more common forms of portal hypertension resulting from cirrhosis. The normal portal vein is conspicuous and readily identifiable on abdominal ultrasound examination. In my survey of 100 randomly selected examinations of the upper abdomen, the portal vein could be seen as it entered the porta hepatis in 97 %; as it crossed the inferior vena cava in 83 % ; and at the level of confluence of the splenic and superior mesenteric veins in 83 % . Failure to visualize the extrahepatic portal vein is usually due to overlying bowel gas but satisfactory visualization can often be obtained if the patient is rescanned at another time. Failure to demonstrate the normal portal vein and its major tributaries should raise the question of portal vein thrombosis. The
Ultrasound
important ultrasonic findings in patients with the latter include: (a) the presence of thrombi within the portal vein; (b) dilation of the splenic and superior mesenteric veins proximal to the point of portal vein occlusion; and (c) loss of normal portal venous landmarks. In most patients with portal vein thrombosis, each of these can readily be demonstrated with currently available gray-scale scanning and real-time equipment. ACKNOWLEDGMENT: Ms. Melissa Reiman, R.D.M.S., provided technical assistance in performing the ultrasound examinations. Christopher R. B. Merritt, M.D. Ochsner Clinic 1514 Jefferson Highway New Orleans, LA 70121
REFERENCES 1. Carlsen EN, Filly RA: Newer ultrasonographic anatomy in the upper abdomen: I. The portal and hepatic venous anatomy. J Clin Ultrasound 4:85-90, Apr 1976 2. Webb LJ, Berger LA, Sherlock S: Gray-scale ultrasonography of portal vein. Lancet 2:675-677, Oct 1977 3. Goldberg BB (ed): Abdominal Gray-Scale Ultrasonography.New York, Wiley, 1977, pp 87-94
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