Ultrasonographic Diagnosis of Portal

Hypertension

Gamal Esmat Cairo University ,Egypt

Professor of Hepatology and Gastroenterology, Faculty of Medicine, Cairo University.President of IASL (International Association for the Study of the Liver) 2006-2008.Member of NCCVH & director of hepatitis treatment centers, NCCVH, MOHP.Consultant of liver transplantation, DAF, Kasr Al Aini.WHO consultant for management of HBV.Director of schistosomal liver unit, Cairo University.Director of international research unit-NHTMRI, MOHP.Head of gastroenterology and hepatology unit, Al Kahera El Fatymia specialized medicine hospital. Director of abdominal ultra-sonographry training program, Egyptian medical syndicate.Coordinator of hepatogastroentrology post-graduate Courses, NTC, MOH

Member of•Egyptian medical society of Tropical Medicine,

Parasitology and Infectious diseases, since1989.•Egyptian medical society of Ultrasonography, since

1988.•Egyptian medical society of Gastroenterology since

1989.•The society of friends of liver patients in the Arab World

since 1991.•American Society of Tropical Medicine, since 1992.

•Mediterranean and African Association of Ultrasonography since 1999.

•Egyptian Medical Society of Hepatology since 1998. •Permanent secretary of the African association of the

study of liver disease.•Fellow of the Maryland University at Baltimore

•Fellow of Edward Herriot hospital at Lyon FranceAwards and Qualifications:Cairo Physician Excellency Award from Egyptian Medical Syndicate 1998.

Diagnosis of Portal Hypertention

Non invasive methodsImaging techniques: Doppler /Ultrasonography,

CAT can, MRI and elastography * EndoscopyInvasive methods* Sus-hepatic catheter (pressure gradient) * Selective celio-mesenteric arteriography (portal angiography)

Ultrasound is of great importance in the diagnosis of liver diseases due to the technical improvements during last years.Main indications for an ultrasound examination are:• the primary diagnosis of chronic liver disease

and portal hypertension • the screening for hepatocellular carcinoma.

Findings of portal hypertension include an increased diameter of the portal vein and the presence of collateral veins. Ultrasonography is also useful for detecting splenomegaly, ascites, and portal vein thrombosis.

US evaluation of PHThe diameter of the portal vein is measured while the patient is in supine position, in quiet respiration, and fasting for a minimum of 6 hours. Measurements are made at the point at which the portal vein crosses the IVC. In an individual without portal hypertension (PH), the diameter of the portal vein is 13 mm or 16 mm during deep inspiration.

Under standard conditions, measurements greater than 13 mm indicate PH with a specificity of 100% but with a low sensitivity of 45–50%.

Sensitivity may be increased to 81% by measuring splenic vein and superior mesenteric vein diameters.

Dilated Portal vein

Portal Vein Thrombosis

Collaterals

The presence of any collaterals is a sure sign of Portal HypertensionPara umbilical vein : seen in the falciform ligament.Coronary vein : seen in the inferior surface of the left lobe normally less than 5 mm. It is related to oesophageal varices.Splenic hilum collaterals: around splenic vein

fundal varices.

Ultrasound in Hepato-splenic Schistosomiasis

The sonographic pattern for schistosomiasis periportal fibrosis is characteristic and is not mimicked by other hepatic diseases. Schistosomiasis could be separated from cirrhosis, as well as from combined lesions.sonography gave accurate diagnosis and grading of scistosomal hepatic fibrosis

Diffuse liver disease

Schistosomal hepatic fibrosis: (Thickened portal tracts):

•Portal tracts appear in US as portal vein radicles only. If the wall of these radicles are thickened, we measure the portal tracts (outer-outer diameter). If the diameter is more than 3 mm in more than 3 tracts → “Periportal Thickening”.US in Hepatobiliary Prof. Gamal Esmat

Non-endoscopic Prediction Of Esophageal Varices In Fibrosis

An ultrasonographic scoring system grading periportal fibrosis, portal vein diameter, spleen size, and portasystemic anastomoses was evaluated as a predictor of esophageal varices proved useful in prediction of presence of esophageal varices.

Ultrasonographic prediction of esophageal varices in Schistosomiasis mansoni.

• Abdel-Wahab MF ,Esmat G ,Farrag A ,el-Boraey Y ,Strickland GT .

• Department of Tropical Medicine, Kasr El Aini Hospital, Cairo University Faculty of Medicine, Egypt

• Am J Gastroenterol 1993, 88:560-3 .

Splenomegaly

The size of the spleen is not well correlated with the level of PH; however, if splenomegaly is absent, PH is unlikely. The spleen is best measured in the coronal plane. In the midaxillary line, a cephalocaudal measurement greater than 13 cm suggests enlargement.

Splenic interface sign

Linear reflective channels are observed in the splenic parenchyma in a variable number of patients with PH.Channels may be explained by dilatation of

intrasplenic venous sinuses with increased collagen in the walls and by periarterial fibrosis. The pathologic changes are known to occur in PH. The splenic interface sign seldom is found in patients with splenomegaly that is unrelated to PH.

Ascites

Uncomplicated PH usually does not cause ascites. Usually, ascites occurs secondary to underlying liver diseases with liver cell failure. US is able to detect minimal ascites and to differentiate between hepatic,cardiac and renal ascites

Gray scale Ultrasound

Doppler Ultrasound In Portal Hypertension

Portal flow direction and velocity

Usually, blood flow in the portal vein is hepatopetal (toward the liver) during the entire cardiac cycle. The mean velocity is 15–18 cm/s and varies with cardiac cycle. In PH, velocity fluctuations disappear, resulting in continuous flow. With a further increase in portal venous pressure, the blood flow direction becomes to-and-fro (biphasic), and finally, the direction is reversed (hepatofugal).

Portal Vein Peak Velocity (PVPV)

Bidirectional flow within the portal vein

Congestive Index

PH may be recognized by use of the congestive index, in which the ratio of the portal vein (in units of square centimeter) is divided by the mean portal flow velocity (in units of centimeter per second). This ratio reflects the physiologic changes that occur in PH (ie, portal vein dilatation associated with diminished flow velocity). In individuals without PH, the ratio should not exceed 0.7.

Arterialization of hepatic blood supply

Hepatic arteries in P H patients are enlarged compared with those of normal hepatic arteries. The arteries also appear tortuous. As portal venous flow to the liver decreases, arterial flow increases. Increased arterial flow occurs with the development of large collaterals and hepatopetal flow.

Hepatic Artery Resistive Index (HARI)

Elastography device

• The ability of a medium to get out of shape

• Named elasticity in physics

• Expressed in Pascal (Pa)

What is elasticity ?

Examples in human liver

0 10 20 30 40 50 60 70 80

20 25 30 35 40 45 50 55 60 65 70 75 80

Time (ms)

Dep

th (m

m)

0 10 20 30 40 50 60 70 80

20 25 30 35 40 45 50 55 60 65 70 75 80

Time (ms)

Dep

th (m

m)

0 10 20 30 40 50 60 70 80

20 25 30 35 40 45 50 55 60 65 70 75 80

Time (ms)

Dep

th (m

m)

VS = 1.1 m/sE ~ 3 kPa

VS = 1.7 m/sE ~ 9 kPa

VS = 3.6 m/sE ~ 40 kPa

F0 F2 F4F1 F3

Measurement of hepatic venous pressure gradient (HVPG) is a standard method for the assessment of portal pressure and correlates with the occurrence of its complications.

If TE is a useful tool to diagnose significant fibrosis and cirrhosis in CLD patients ,however it is not so good in predicting portal hypertension and esophageal varices.

In fact good correlation between stiffness and hepatic-vein portal gradient (HVPG) was found only up to HVPG values of 10-12 mmHg, whereas for higher values the correlation was suboptimal.

This could be explained by the fact that TE measures the initial rise of portal pressure caused by the accumulation of a fibrillar matrix,but not the complex hemodynamic changes of late portal hypertension.

Linear regression analysis between LiverStiffness (kPa) and different degrees of HVPG (mm Hg)

(Vizzuti et al,Hepatology,2007)

Another problem arising from these studies is the wide range of proposed cut offs, varying from 13.9 to 21.3 KPa for all varices and from 19 to 30 KPa for G2 varices. The optimal cut offs therefore are still to be defined.

(Del Poggio P &Colombo S ,World J Gastroentrol,2009)

FibroScanDiagnostic value for complications

63 kPa

Absence of varicesgrade 2 or 3

Absence of Child-Pugh B or C

Absence of history of ascites

Absence of hepatocellular carcinoma

Absence of varice rupture

54 kPa49 kPa27 kPa 37 kPa

Foucher et al. Gut 2006

n = 144 / F3n = 144 / F3--F4F4

AUROC :AUROC :0.73 0.73 –– 0.900.90

Conclusion

US in diagnosis of Portal Hypertension

Gray scale USPV diameterP S collateralsSplenomegalyAscites

Doppler/Duplex USFibroscan

Thank yougesmat@gamalesmat.com