Portal sonography

Portal vein thrombosis (see chapter 39.3.3) with gradual or incomplete obstruction merely produces anastomoses and develops asymptomatically. After complete obstruction, ultrasonography will showparaportal, angiomatous anastomoses, predominantly in the porta hepatis (= cavernous transformation). (95) Splenomegaly is evidenced with a normal-sized liver. The portal vein is not detectable. Colour Doppler sonography has become of paramount importance in portal vein system diagnostics. 

Dokmeci, K., Kimura, K., Matsutani, S., Ohto, T., Tsuchiya, Y., Saisho, H., Okuda, K. Collateral veins in portal hypertension demonstration by sonography. Amer. J. Roentgenol. 1981 137 1173-1177... 

Zoller, W.G., Wagner, D.R., Zentner, J. Effect of propranolol on portal vein hemodynamics in patients with liver cirrhosis assessment by duplex sonography. Z. Gastroenterol. 1993 31 425-428... 

Direct splenoportography is the most informative procedure for visualizing the portal vein system and its collaterals, (s. p. 181) Yet this technique is costly, time-consuming and high-risk. The injection of contrast medium into the spleen is carried out either percu-taneously (sonography-gmded) or, preferably, by laparoscopy. It is also possible to measure the pressure in the portal vein system. In addition, this method ensures access to the collaterals if radiological obliteration is planned, (s. p. 181)... 

K., Kawamori, ., Takashima, T. Gallbladder varices demonstration of direct communication to intrahepatic portal veins by color Doppler sonography and CT during arterial portography. Abdom. Imag. 1997 22 82-84... 

Gibson, P.R., Gibson, R.N., Ditchfield, M.R., Donlan, J.D. A comparison of duplex Doppler sonography of the ligamentum teres and portal vein with endoscopic demonstration of gastroesophageal varices in patients with chronic hver disease or portal hypertension, or both. J. Ultrasound Med. 1992 11 327 - 331... 

H.F. Recurrent bleeding after variceal hemorrhage predictive value of portal venous duplex sonography. Amer. J. Roentgenol. 1993 160 41-47... 

Wachsbei, R.H., Simmons, M.Z. Coronary vein diameter and flow direction in patients with portal hypertension evaluation with duplex sonography and correlation with variceal bleeding. Amer. J. Roentgenol. 1994 162 637- 641... 

Fig. 35.12 Colour-encoded duplex sonography retrograde portal flow (flow inversion) in both branches and in the trunk of the portal vein due to arterioportal shunts...

Fig. 39.7 I Re-opened umbilical vein (VU) due to pronounced portal hypertension in haemochromatotic cirrhosis (VP = umbilical branch of the left portal vein) II Hepatofugal blood flow in the umbilical vein (VU) depicted by colour-encoded duplex sonography...

With unclarified abdominal pain, sonography is usually the diagnostic procedure of choice. An aneurysm appears as a round or oval focus either intrahepatically or extrahepatically between the portal hilum and the pancreas. The hypoechoic, cystic focus may contain hyperechoic, thrombotic material. Occasionally, there is a connection to an afferent vessel. (128) A suspected aneurysm can be confirmed by colour Doppler sonography, with the possibility of distinguishing blood flow and arterial blood. An echo-free aneurysm provides a typical arterial sphygmogram. 

Previous shunt operations and TIPS need to be removed in order to guarantee that the transplanted liver is sufficiently supplied with portovenous blood. In these cases, the portal system is checked preoperatively for thromboses by means of colour-encoded duplex sonography and X-ray techniques. In any case, the confluence of superior mesenteric vein and splenic vein must be free. (391) The main advantage of portacaval end-to-side anastomosis is its low thrombosis rate of < 5% in addition, there is no need for a distal shunt ligature. In shunts distal to the hilus (mesocaval, distal splenorenal), no preparation of the liver hilus is required however, in 10% of cases, these shunts show portal vein thrombosis (in TIPS, up to 15%). Usually, all surgical shunts are disconnected or ligated before the liver transplantation is completed in order to... 

Partial duodenal obstruction may be produced by duodenal stenosis, duodenal web, Ladd s bands, midgut volvulus, annular pancreas, preduodenal portal vein, and duplication cyst. Plain radiographs show gaseous distension of the stomach and duodenum with a normal or diminished quantity of air in the small bowel. Content studies may be necessary to differentiate between midgut volvulus and partial duodenal obstruction caused by a web or stenosis (Auringer and Sumner 1994). Sonography is helpful to rule out extraluminal causes such as a duplication cyst. 

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