UltrasonographicDiagnosis of Portal Hypertension Gamal Esmat Cairo University ,Egypt
Professor of Hepatology and Gastroenterology, Facultyof Medicine, Cairo University.President of IASL (International Association for theStudy of the Liver) 2006-2008.Member of NCCVH & director of hepatitis treatmentcenters, 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, AlKahera El Fatymia specialized medicine hospital.Director of abdominal ultra-sonographry trainingprogram, Egyptian medical syndicate.Coordinator of hepatogastroentrology post-graduateCourses, NTC, MOH
Member ofEgyptian 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 France•Awards and Qualifications:Cairo Physician Excellency Award from Egyptian MedicalSyndicate 1998.
Ultrasound is of great importance in thediagnosis of liver diseases due to thetechnical improvements during last years.Main indications for an ultrasoundexamination are:• the primary diagnosis of chronic liver disease and portal hypertension• the screening for hepatocellular carcinoma.
Findings of portal hypertension includean increased diameter of the portal veinand the presence of collateral veins.Ultrasonography is also useful fordetecting splenomegaly, ascites, andportal vein thrombosis.
US evaluation of PHThe diameter of the portal vein is measuredwhile the patient is in supine position, inquiet respiration, and fasting for a minimumof 6 hours.Measurements are made at the point at whichthe portal vein crosses the IVC.In an individual without portal hypertension(PH), the diameter of the portal vein is 13mm or 16 mm during deep inspiration.
Under standard conditions, measurementsgreater than 13 mm indicate PH with aspecificity of 100% but with a low sensitivityof 45–50%.Sensitivity may be increased to 81% bymeasuring splenic vein and superiormesenteric vein diameters.
Collaterals The presence of any collaterals is a sure sign ofPortal HypertensionPara umbilical vein : seen in the falciform ligament.Coronary vein : seen in the inferior surface of the leftlobe normally less than 5 mm.It is related to oesophageal varices.Splenic hilum collaterals: around splenic vein fundal varices.
Ultrasound in Hepato-splenic SchistosomiasisThe sonographic pattern for schistosomiasisperiportal fibrosis is characteristic and is notmimicked by other hepatic diseases.Schistosomiasis could be separated fromcirrhosis, as well as from combined lesions. sonography gave accurate diagnosis andgrading of scistosomal hepatic fibrosis
Diffuse liver diseaseSchistosomal hepatic fibrosis:(Thickened portal tracts):Portal tracts appear in US as portal vein •radicles only. If the wall of these radiclesare thickened, we measure the portaltracts (outer-outer diameter). If thediameter is more than 3 mm in more than 3tracts → “Periportal Thickening”.US in Hepatobiliary Prof. Gamal Esmat
Non-endoscopic Prediction OfEsophageal Varices In FibrosisAn ultrasonographic scoring systemgrading periportal fibrosis, portal veindiameter, spleen size, and portasystemicanastomoses was evaluated as apredictor of esophageal varices proveduseful in prediction of presence ofesophageal varices.
Ultrasonographic prediction of esophagealvarices 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 .
SplenomegalyThe size of the spleen is not wellcorrelated with the level of PH; however,if splenomegaly is absent, PH is unlikely.The spleen is best measured in thecoronal plane. In the midaxillary line, acephalocaudal measurement greaterthan 13 cm suggests enlargement.
Splenic interface signLinear reflective channels are observed in thesplenic parenchyma in a variable number ofpatients with PH. Channels may be explained by dilatation ofintrasplenic venous sinuses with increasedcollagen in the walls and by periarterial fibrosis.The pathologic changes are known to occur in PH.The splenic interface sign seldom is foundin patients with splenomegaly that is unrelated toPH.
AscitesUncomplicated PH usually does not causeascites.Usually, ascites occurs secondary to underlyingliver diseases with liver cell failure.US is able to detect minimal ascites and todifferentiate between hepatic,cardiac and renalascites
Portal flow direction and velocityUsually, 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 withcardiac cycle. In PH, velocity fluctuationsdisappear, 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).
Congestive IndexPH may be recognized by use of the congestiveindex, in which the ratio of the portal vein (inunits of square centimeter) is divided by themean portal flow velocity (in units ofcentimeter per second).This ratio reflects the physiologic changes thatoccur in PH (ie, portal vein dilatationassociated with diminished flow velocity). Inindividuals without PH, the ratio should notexceed 0.7.
Arterialization of hepatic blood supplyHepatic arteries in P H patients are enlargedcompared with those of normal hepaticarteries.The arteries also appear tortuous. As portalvenous flow to the liver decreases, arterialflow increases.Increased arterial flow occurs with thedevelopment of large collaterals andhepatopetal flow.
What is elasticity ? • The ability of a medium to get out of shape • Named elasticity in physics • Expressed in Pascal (Pa)
Examples in human liver 20 20 20 25 25 25 30 30 30 35 35 35 40 40 40Depth (mm) Depth (mm) Depth (mm) 45 45 45 50 50 50 55 55 55 60 60 60 65 65 65 70 70 70 75 75 75 80 80 80 0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80 Time (ms) Time (ms) Time (ms) VS = 1.1 m/s VS = 1.7 m/s VS = 3.6 m/s E ~ 3 kPa E ~ 9 kPa E ~ 40 kPa F0 F1 F2 F3 F4
Measurement of hepatic venous pressure gradient(HVPG) is a standard method for theassessment of portal pressure and correlateswith the occurrence of its complications.If TE is a useful tool to diagnose significant fibrosisand cirrhosis in CLD patients ,however it is notso good in predicting portal hypertension andesophageal varices.
In fact good correlation between stiffness and hepatic-vein portal gradient (HVPG) was found only up toHVPG values of 10-12 mmHg, whereas for highervalues the correlation was suboptimal.This could be explained by the fact that TE measuresthe initial rise of portal pressure caused by theaccumulation of a fibrillar matrix,but not the complexhemodynamic 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 isthe wide range of proposed cut offs, varyingfrom 13.9 to 21.3 KPa for all varices andfrom 19 to 30 KPa for G2 varices. Theoptimal cut offs therefore are still to bedefined. (Del Poggio P &Colombo S ,World J Gastroentrol,2009)
FibroScan Diagnostic value for complications 27 kPa 37 kPa 49 kPa 54 kPa 63 kPan = 144 / F3-F4 Absence of varices grade 2 or 3 AUROC :Absence of Child-Pugh B or C 0.73 – 0.90 Absence of history of ascites Absence of hepatocellular carcinoma Absence of varice rupture Foucher et al. Gut 2006
ConclusionUS in diagnosis of Portal HypertensionGray scale US PV diameter P S collaterals Splenomegaly AscitesDoppler/Duplex USFibroscan