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June 1985, Volume 35, Issue 6

Special Communication

Ultrasonography in Hepatobiliary diseases

Kunio Okuda  ( Department of Medicine, Chiba University School of Medicine, Chiba, Japan (280). )

Introduction of real-time linear scan ultrasonography to clinical practice has revolutionalized the diagnostic approach to hepatobiiary disorders.1 This modality allows the operator to scan the liver and biliary tract with a real-time effect, and obtain three dimensional images. One can follow vessels and ducts from one end to the other. The portal and hepatic venous systems are readily seen and distinguished. Real-time ultrasonography (US) using an electronically activated linear array transducer is becoming a stethoscope for the liver specialist, because a portable size real-time ültrasonograph is already available.
It is now established that real-time US is useful not only in the diagnosis of gallstones, dilatation of the biliary tract, and cystic lesions, but it can also assess liver parenchyma in various diffuse liver diseases. Thus, a wide range of diffuse liver diseases beside localized hepatic lesions can he evaluated by US. It can also make the diagnosis of portal hypertension2-4
In our unit, the patient with a suspected hepatobiiary disorder is examined by US on the first day of hospital visit, and the next investigation that will pOssibly provide a definitive diagnosis, such as ERCP, PTC, X-ray CT, angiography, scintigraphy, etc., is scheduled. Using a specially designed transducer, a needle can be guided while the vessel, a duct, or a structure is being aimed and entered (US-guided puncture).5 ;7 US-guided puncture technique has improved the procedure for percutaneous transhepatic cholangiogrpahy8, biliary decompression, percutaneous transhepatic catheterizatiøn for portography9, and obliteration of bleeding varices. The following are the major diagnostic applications of real-time US.
Biliary Tract Diseases
Gallstone disease. Gallstones in the gallbladder greater than 6 mm invariably and those between 3 and 6 mm almost always display strong echoes and posterior acoustic shadowing.

Figure 1 depicts typical acoustic shadows as related to the size and nuthber of stones. It even provides indirect information regarding the chemi­cal composition of the stones.

Table I gives the number of patients found to have cholelithiasis in a five year period at a large hospital in Japan during which time conventional cholecystography was gradually replaced by US examination as the routine investigation for suspected stone disease. There was a two-fold increase in the number of cases diagnosed.

Table II compares capability of intravenous cholecystocholangiography and US in 32 patients in whom stones were suspected but oral cholecystography failed to make the diagnosis. In this study, US identified stones in 28, or 87.5% of them.
Obstructive /aundice. The sizes of various parts of the biliary tract as measured by US in Japanese adults are given in Table III.

The normal diameters of the left and right hepatic ducts were 1.7 mm, and of the extrahepatic bile duct, 3.0-3.3 mm. These figures are somewhat smaller than those obtained by cholangiography. It is probably due to excess echoes from the wall reducing the 4iameter of the lumen. In obstructive jaundice, these figures are clearly increased, and such dilation is readily recognized by US’ Differential diagnosis of obstuctive jaundice and intrahepatic cholestasis was possible by US alone in 174 of 175 patients (99.4%) (Table IV).

The only failure in diagnosis occurred in a patient with hilar carcinoma which was infiltrating along the major intrahepatic bile ducts causing no visible dilatation of the biiary tract.
Although the scanning of the extrahepatic bile duct is often hampered by. intestinal gas, repeated examination will yield information for the determination of whether the obstructing lesion is located proximally or distally. Often, but less frequently, the distal end of the obstructing lesion is discerned (Table V).





Figure 2 illustrates the US finding of a distal bile duct carcinoma and its cholangiogram.
Intrahepatic stones. Intrahepatic stones or hepatolithiasis is a common disorder in the Far East10, as contrasted by the Western countries where it is a rarity. In Hong Kong, recurrent pyogenic cholangitis secondary to intrahepatic stones is one of the major surgical problems. For the detection of intrahepatic stones, US proves most diagnostic, particularly when it is combined with UG-guided PTC (Table VI).


U-guided PlC and biliary drainage. With the use of the puncture transducer5-7, an intrahepatic bile duct greater than 5mm can be aimed and entered with a very high success rate. Since puncture carried out while the vessels and ducts are being observed, inadvertent puncture of blood vessels can be avoided. Similarly, transhepatic biiary decompression and drainage in obstructive jaundice11,12 can be easily achieved with the use of US guidance system, avoiding damage to blood vessels, which is the major cause of severe complications (Table VII).


Liver Diseases
Hepatic tumors. US is very sensitive in detecting space occupying lesions. However, due to lung air, examination of the anterior superior area of the right lobe is not always reliable. For more accurate examination of this particular area, other types of grey-scale scanner may be used. Small hepatocellular carcinoma (HCC) is usually solitary, and has a hypoechoic interior or an anechoic rim around (Fig.3), in contrast to metastatic tumors which are frequently hyperechoic or mixed hypo. and hyperechoic, and multiple13 Large hemangioma is invariably hyperechoic, but some of the very small ones may not be distinguishable from small HCC. US examination carried out regularly at a set interval in patients with cirrhosis together with measurement of serum aipha-fetoprotein is an established practice in Japan for the early detection of HCC, and hundreds of cases of small HCC have been found14,15. In advanced cases, the portal vein system should be carefully examined to determine whether a major portal branch has already been invaded (Fig.4). Such information is important when hepatic resection is contemplated.
Cysts and abscesses. Cysts, whether simple, hydatid, or otherwise, are seen as round anechoic lesions with exaggerated back echoes due to reduced attenuation. Whereas the shape of cysts is circular, that of an abscess is much more irregular, and the interior has more echoes. Abscess in its early phase of formation may look like a mass, but after liquefaction, the interior looks more like a cyst except for the shape. 16 Ultrasound guided puncture and drainage is now an established procedure for the treatment of liver abscess17-. We have treated 21 consecutive cases of idiopathic liver abscess by puncture and/or drainage combined with systemic antibiotics without requiring operation.
Liver cirrhosis. The surface of a normal liver is smooth as seen by US, and a grossly nodular liver surface can easily be recognized. Obtunded angle of the liver edge is another important finding ‘to suggest cirrhosis. Ascites which is also readily recognized by US, and signs of portal hypertension discussed below are highly suggestive of cirrhosis
Portal hypertension. The size of the spleen can be semiquantitatively assessed by the left intercostal scan18. Increased diameters of the portal trunk and major branches of the portal vein suggest portal hypertension. Large shunts involving the left renal vein are seen as a cystic lesion in front of the spleen19. The umbilical portion of the left portal vein branch is perpendicular to the anterior plane of the body, and readily recognized by US; if a dilated paraumbilical vein is seen coursing anteriorly and inferiorly along the round ligament, it is a good indication of portal hypertension. The left gastric (coronary) vein which is the main feeding vein for esophageal varices, can also be discerned in the section where the splenic vein, left lobe of the liver and the lower esophagus are seen2.
Fatty liver. Normal liver parenchyma and renal parenchyma have similar echo patterns. In advanced fatty liver, the liver exhibits much stronger echoes diffusely, and the difference from the renal parenchyma as a control is evident in a section in which both the liver and kidney are seen.
Vascular diseases. Thrombosis of the hepatic vein and membranous obstruction of the inferior vena cava (Budd-Chiari syndrome)20 can be diagnosed by US. For more definitive diagnosis, angiographic examination is required. In the eyes of the experienced hepatologist-sonographer, cavernous transformation of the portal vein in the hilar area, indirect evidence for portal obstruction, is seen as an irregular vascular structure21
Other diseases. In acute hepatitis, intrahepatic vascular structures show exaggerated walls. Advanced schistosomiasis demonstrates irregular echoes in the liver, and they may prove diagnostic in the endemic areas.
Summary
Real-time ultrasonography is imperative in the diagnosis of hepatobiliary diseases in modern medicine. It will prove diagnostic not only for gallstones, biliary obstruction and localized hepatic lesions, but also for some of the diffuse liver diseases such as cirrhosis. It must be done as a routine, as is the stethostope used by the physician, in patients in whom hepatobiiary disease is suspected.

References

1. Okuda, K. Advances inhepatobiiary ultrasonography. Hepatology, 1981; 1: 662.
2. Dokmeci, A.K., Kimura, K., Matsutani, S., Ohto, M., Ono, T., Tsuchiya, Y., Saisho, H. and Okuda, K. Collateral veins in portal hypertension;demonstration by sonography. AJ.R., 1981; 137 : 1173.
3. Schabel, S.I., Rittenberg, G.M., Javid, L.H., Cunningham, J. and Ross, P. The “bull’s-eye” falciform ligament; a sonographic finding of portal hypertension. Radiology, 1980; 136: 157.
4. Galzer, G.M., Laing, F.C., Brown, T.W. and Gooding, G.A.W. Sonographic demonstration of portal hypertension; the patent umbilical vein.1 Radiology, 1980; 136: 161.
5. Ohto, M., Karasawa, E., Tsuchiya, Y., Kimura, K., Saisho, H., Ono, T., and Okuda, K. Ultrasonically guided percutaneous contrast medium injection and aspiration biopsy using a real-time puncture trasducer. Radiology, 1980; 136: 171.
6. Makuuchi, M., Bandai, Y., Ito, T., Watanabe, G., Wada, T., Abe, H. and Muroi, T. Ultrasonically guided percutaneous transhepatic bile drainge; a single-step procedure without cholangiography. Radiology, 1980; 136: 165.
7. Grant, E.G., Richardson, LD., Smirniotopoulos, J.G. and Jacobs, N.M. Fine-needle biopsy directed by real-time sonography; techinque and accuracy. A.J.R., 1983; 141 : 29.
8. Okuda, K., Tsuchiya, Y. and Saisho, H. Imaging of the biiary and pancreatic ducts. Surv Dig. Dis., 1984; 2: 13.
9. Kimura, K., Tsuchiya, Y., Ohto, M., Ono, T., Matsutani, S., Kimura, M., Ebara, M., Saisho, H. and Okuda, K. Single-puncture method for percutaneous transhepatic portography using a thin needle. Radiology, 1981; 139: 748.
10. Okuda, K., Nakayama, F. and Wong, J. Intrahepatic calculi New York, Alan R. Liss, 1984.
11. Molnar, W. and Stockum, A.E Relief of obstructive jaundice through percutaneous transhepatic catheter; a new therapeutic method. Am. J. Roentgenal., 1974; 122: 356.
12. Nakayama, T., Ikeda, A. and Okuda, K. Percutaneous transhepatic drainage of the biiaxy tract; technique and results in 104 cases. Gastroenterology, 1978; 74: 554.
13. Shinagawa, T., Ohto, M., Kimura, K., Matsutani, S., Kimura , K., M Unosawa, T., Ukaji, H., Tsunetomi, S., Nakano, T., Morita, M., Saisho, H, Tsuchiya, Y., Ono, T., and Okuda, K. Realtime ultrasonographic diagnosis of hepatocellular carcinoma. Jpn. J. Gastroenterology, 1982; 78: 2402.
14. Obata, H., Hayashi, N., Motoike, Y., Hisamitsu, T., Okuda, H., Kobayashi, S. and Nishioka, K. A prospective study on the development of hepatocellular carcinoma from liver cirrhosis with persistent hepatitis B virus infection. Int. J.Cancer, 1980; 25: 741.
15. Shinagawa, T., Ohto, M., Kimura, K., Tsunetomi, S., Morita, M., Saisho, H., Tsuchiya, Y., Saotome, N., Karasawa, E., Miki, M., Ueno, 1., and Okuda, K. Diagnosis and clinical features of small hepatocellular carcinoma with emphasis on the utility of real-time ultrasonography. A study in 51 patients. Gastroenterology, 1984; 86 : 495.
16. Sukov, R.J., Cohen, Li. and Sample, W.F. Sonography of hepatic amebic abscesses. A.J .R., 1980;134 :911.
17. Kimura, M., Tsuchiya, Y., Ohto, M., Kimura, K., Ebara, M., Saotome, N., Karasawa, E., Saisho, H., Ono, T. and Okuda, K. Ultrasonically guided percutaneous drainage of solitary liver abscess; successful treatment in four cases. J. Clin. Gastroenterol., 1981; 3:61.
18. Niederau, C., Sonnenberg, A., Muller, J.E., Erckenbrecht, J.F., Scholten, T. and Fritsch, W.P. Sonographic measurements of the normal liver, spleen, pancreas, and portal vein. Radiology 1983; 149: 537.
19. Takayasu, K., Moriyama, N., Shima, Y., Yamada, T., Kobayashi, C., Musha, H. and Okuda, K. Sonographic detection of large spontaneous spleno-renal shunts and its clinical significance. Br.J.Radiol., 1984;57 : 565.
20. Okuda, K. and Ostrow, J.D. Membranous type of Budd-chiari syndrome. J. Clin. Gastroenterol., 1984; 6:81.
21. Kimura, K., Okuda, K., Takara, K., Matsutani, S. and Lesmana, L. Membranous obstruction of the portal vein. A case report. Gastroenterology, 1985;88: 571.

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