9 Liver and Biliary System



10.1055/b-0035-122525

9 Liver and Biliary System

Rick van Rijn and RAJ Nievelstein

Diagnosing liver and biliary tract disease requires, besides obtaining a solid clinical examination and a thorough clinical history, proper radiologic imaging. As in all pediatric imaging, close collaboration between the radiologist and the clinician is key to success.


Ultrasonography (US) plays an important role in imaging the pediatric liver and biliary tract. As children are optimal candidates for US, this is even more so the case than in adults. Computed tomography (CT) and magnetic resonance (MR) imaging are second-line imaging strategies, and because of radiation issues, MR imaging is preferred to CT.


The US examination should start with an overview of the whole liver and biliary tract in order not to miss abnormalities once a more focused examination of the liver is undertaken. A curved transducer with an appropriate frequency (for children who are not obese, in the range of 4 to 9 MHz) suffices. For the detection of more subtle changes in the liver architecture, a high-frequency linear transducer should be used. Assessing flow in the hepatic veins, portal veins, and hepatic artery should be seen as a standard part of liver imaging as abnormalities in flow can lead to a correct diagnosis of disease. For a proper evaluation of the biliary tract, it is important that the patient has fasted before the examination. A normal distended gallbladder is a sign that the patient has indeed fasted ( Fig. 9.1 ).

Fig. 9.1 Well distended gallbladder in a 12-year-old girl. For patient comfort, these examinations, which require fasting, should be planned in the morning.

In addition, imaging of the liver is incomplete if the spleen is not evaluated (see Chapter 10).



Tips from the Pro




  • Younger children, in general, do not hold their breath if you ask them to do so. However, if you make it a challenge (e.g., a game between the child and radiologist), you will be amazed about how long they can hold their breath.



9.1 Normal Anatomy and Variants


The liver is the largest solid organ of the human body, accounting for approximately 2 to 3% of the total body weight. In young children, the liver is relatively large compared to the liver in adolescents and adults ( Table 9.1 , Table 9.2 , Table 9.3 , Table 9.4 ). The anatomy of the liver can be described in two ways: anatomically and functionally. The anatomical description is based on the external surface anatomy and as such is not useful in daily clinical practice. The functional anatomy is based on the relationship between vessels and the biliary tract. Claude Couinaud (1922–2008) was the first to recognize the importance of this functional segmentation in relation to surgery. For imaging purposes, the liver is divided into eight segments ( Fig. 9.2 ). The middle hepatic vein divides the liver into left and right lobes.










































Table 9.1 Liver length in premature infants and neonates

Gestational age (weeks)



Liver length in the midclavicular line (cm)



No. of patients


Mean length (±1 SD)


Minimum–maximum


24–31


29


3.7 (0.7)


2.8–5.8


32–35


33


4.6 (0.7)


3.2–6.2


36–37


35


5.4 (0.6)


3.5–6.3


38–41


153


5.5 (0.8)


3.9–7.8


Abbreviation: SD, standard deviation.


Source: Reprinted with permission of Elsevier from Soyupak SK, Narli N, Yapicioglu H, Satar M, Aksungur EH. Sonographic measurements of the liver, spleen and kidney dimensions in the healthy term and preterm newborns. Eur J Radiol 2002;43(1):73–78.


Note: An ultrasonographic study was performed in 261 healthy newborn infants. Craniocaudal dimensions of the liver in the midclavicular line were determined.













































































Table 9.2 Liver length in children

Age (years)



Liver length in the midclavicular line (cm)



No. of patients


Mean (SD)


Limits of normal


0–0.25


53


6.4 (1.0)


4.0–9.0


0.25–0.5


40


7.3 (1.1)


4.5–9.5


0.5–0.75


20


7.9 (0.8)


6.0–10.0


1–2.5


18


8.5 (1.0)


6.5–10.5


3–5


27


8.6 (1.2)


6.5–11.5


5–7


30


10.0 (1.4)


7.0–12.5


7–9


38


10.5 (1.1)


7.5–13.0


9–11


30


10.5 (1.2)


7.5–13.5


11–13


16


11.5 (1.4)


8.5–14.0


13–15


23


11.8 (1.5)


8.5–14.0


15–17


12


12.1 (1.2)


9.5–14.5


Abbreviation: SD, standard deviation.


Source: Reproduced with permission of the American Journal of Roentgenology from Konus OL, Ozdeimer A, Akkaya A, Erbas G, Celik H, Isik S. Normal liver, spleen, and kidney dimensions in neonates, infants, and children: evaluation with sonography. AJR Am J Roentgenol 1998;171(6):1693–1698.


Note: This study included 307 pediatric subjects (169 girls and 138 boys). The age range was from full-term newborns (5 days) to 16 years. The subjects were imaged in the supine position. The upper margin of the midclavicular liver dimension was defined as the uppermost edge under the dome of the diaphragm; the lower margin was defined as the lowermost edge of the lobe.





































































Table 9.3 Common bile duct diameter in children

Age (years)


Diameter of common bile duct (mm)


95% confidence interval


0


0.7


0.2–1.6


1


1.2


0.2–1.7


2


1.0


0.3–1.8


3


1.3


0.3–1.9


4


1.1


0.4–2.0


5


0.8


0.5–2.1


6


1.2


0.5–2.2


7


1.3


0.6–2.3


8


1.5


0.6–2.4


9


1.9


0.7–2.5


10


1.7


0.7–2.6


11


1.7


0.8–2.7


12


1.9


0.8–2.8


Source: Adapted from Hernanz-Schulman M, Ambrosino MM, Freeman PC, Quinn CB. Common bile duct in children: sonographic dimensions. Radiology 1995;195:193–195.


Note: This study included 173 children (100 boys and 73 girls) ranging in age from 1 day to 13 years (median age, 5.0 years). The diameter of the common bile duct was ≤ 3.3 mm in all children.












































Table 9.4 Gallbladder volume in term and preterm infants


Gallbladder volume (mL)



Term neonates


Preterm neonates


Number of observations


46


50


At birth


1.1 (0.2–2.4)


0.7 (0.1–1.2)


At 6 hours after birth


1.0 (0.2–2.2)


0.7 (0.1–1.2)


Number of observations after regular feeding


46


50


After 3 hours of fasting


0.08 (0–0.02)


0.08 (0–0.2)


After 6 hours of fasting


0.7 (0.1–1.3)


0.3 (0.1–0.9)


Source: Reprinted with permission from Ho ML, Chen JY, Ling UP, Su PH. Gallbladder volume and contractility in term and preterm neonates: normal values and clinical applications in ultrasonography. Acta Paediatr 1998;87:799–804.


Note: Ultrasound assessment of gallbladder volume (length × width × height × π/6) was performed in 50 preterm infants (mean gestational age, 31.7 ± 2.5 weeks) and 46 term infants (mean gestational age, 38.3 ± 1.2 weeks).


Fig. 9.2 Schematic depiction of the eight liver segments as defined by Couinaud.

The liver vasculature has many normal variants, ranging from a relatively commonly seen accessory hepatic vein draining directly into the inferior caval vein ( Fig. 9.3 ) to hepatic arteries arising from the superior mesenteric arteries. The same holds true for the biliary anatomy, as the classic anatomy (in which the right and left hepatic ducts drain into a common hepatic duct) occurs in only 58% of the population. For surgical planning, these normal variants can be of importance, and in complex cases, cross-sectional imaging with CT or MR imaging is warranted.

Fig. 9.3 a Accessory hepatic vein draining segment 6 in a 13-year-old girl who underwent abdominal ultrasonography as part of a routine follow-up for treated Wilms tumor. b Color Doppler imaging shows the direction of flow in the accessory hepatic vein.

In pediatric radiology, it is important, when caring for neonates, to be aware of the fetal vascular anatomy. Especially in premature infants, the umbilical vein and the ductus venosus can be visualized, and sometimes a closing vein can be depicted ( Fig. 9.4 ; Video 9.4).

Fig. 9.4 Thrombus formation in the umbilical vein (arrow). Note the relation to the portal vein (open arrow); see Video 9.4.


9.2 Normal Measurements



9.2.1 Portal Venous Flow


The portal vein in children shows a homogeneous hepatopetal flow in the range of 20 cm/s ( Table 9.5 ; Fig. 9.5 ); this is comparable to the adult situation. Respiration leads to a slight fluctuation in the flow pattern.























































































Table 9.5 Normal portal venous diameter


Portal venous diameter


Age (years)


Mean (mm)


Limits of error


0


4.5


3.0–6.3


1


5.7


3.6–7.8


2


6.5


4.2–8.8


3


7.0


5.5–8.5


4


6.8


5.5–8.2


5


7.0


5.2–8.7


6


7.7


5.0–10.3


7


7.7


4.8–10.6


8


7.2


5.3–9.0


9


7.6


5.7–9.5


10


8.2


5.0–11.3


11


8.7


6.1–11.3


12


9.5


6.7–12.1


13


9.2


6.9–11.4


14


9.0


6.2–12.0


15


10.2


9.0–11.5


16


11.0


7.8–14.2


Source: Table created from data within Patriquin HB, Perreault G, Grignon A, et al. Normal portal venous diameter in children. Pediatr Radiol 1990:20:451–453, with kind permission from Springer Science+Business Media.


Note: The study included 150 children, ages 0 to 16 years, without clinical evidence of liver or intestinal disease referred for abdominal


Ultrasound. The portal vein was visualized in the longitudinal axis from the splenomesenteric junction to the liver hilum. The greatest anteroposterior (AP) diameter was measured at the site where the hepatic artery crosses the portal vein.


Fig. 9.5 a Normal portal venous flow in the main portal vein. b Normal portal venous flow in the left portal vein. c Normal portal venous flow in the right portal vein.


9.2.2 Hepatic Arterial Flow


The hepatic artery shows a hepatopetal arterial flow with a characteristic low-resistance and high-velocity diastolic flow ( Fig. 9.6 ). In adults, the reported peak systolic flow is 30 to 40 cm/s, and the end-diastolic flow is 10 to 15 cm/s.

Fig. 9.6 Normal hepatic arterial flow.


9.2.3 Hepatic Venous Flow


The hepatic veins show a triphasic flow consisting of two waves toward the heart (i.e., atrial diastole and ventricular systole) and a small wave away from the heart (i.e., atrial systole) ( Fig. 9.7 ).

Fig. 9.7 Normal hepatic triphasic flow in a healthy 10-year-old boy.


Tips from the Pro




  • Children love it when you tell them that they have a bunny in their tummy. If you try, you can depict the hepatic veins as resembling the well-known playboy bunny sign™ ( Fig. 9.8 ).

Fig. 9.8 Bunny sign.


9.3 Pathology



9.3.1 Congenital Anomalies



Biliary Atresia

Biliary atresia is a congenital obstruction of the intra- and/or extrahepatic ducts, usually presenting with neonatal jaundice. The overall incidence is approximately 1 in 15,000 births, but it is far more common in the Asian population.


The most common finding on US (seen in almost two-thirds of neonates with biliary atresia) is an absent, small (< 1.5 cm), or empty gallbladder in a neonate who has been fasting for several hours ( Fig. 9.9 a). Furthermore, a triangular or tube-shaped echogenic focus with a thickness of 4 mm or more that follows the portal veins can be seen at the porta hepatis ( Fig. 9.9 b). This so-called triangular cord sign has a reported sensitivity of 62 to 93% and a specificity of 96 to 100%, but can be difficult to distinguish from periportal echogenicity due to inflammation or cirrhosis. Other signs that suggest the presence of biliary atresia include an absent common bile duct, a hypertrophic hepatic artery ( Fig. 9.9 b,c), and increased hepatic subcapsular flow on color Doppler US ( Fig. 9.9 d).

Fig. 9.9 a–d One-month-old girl with persistent neonatal cholestasis. a There is a small gallbladder (arrow) after prolonged fasting. b Ultrasonography shows increased echogenicity in the porta hepatis (triangular cord sign; arrow) and an enlarged hepatic artery (open arrow). c Color Doppler imaging shows the enlarged hepatic artery (arrow). d Color Doppler imaging shows increased subcapsular vascularity in the liver parenchyma. These imaging findings are characteristic for biliary atresia, which was biopsy-proven in this girl.


Choledochal Cysts

Choledochal cysts are rare congenital saccular or fusiform dilatations of the biliary tree with an incidence of approximately 1 to 2 in 100,000 to 150,000 live births. Again, they are far more common in the Asian population, with a reported prevalence of 1 in 1,000 persons in Japan. Choledochal cysts are usually classified according to Todani into five subtypes ( Fig. 9.10 ). Type I cysts, the most common, occur in up to 80 to 90% of all cases ( Fig. 9.11 and Fig. 9.12 ). They are often associated with an abnormal junction of the common bile duct with the pancreatic duct. Frequent complications include ascending cholangitis and/or pancreatitis, liver cirrhosis, portal hypertension, and spontaneous cyst rupture. There is an increased risk for developing cholangiocarcinoma, especially after the age of 10 years. In cases of delayed presentation, these cysts can become extremely large ( Fig. 9.13 ).

Fig. 9.10 Schematic representation of the classification of choledochal cysts according to Todani: type I, fusiform dilatation of the common bile duct below the cystic bile duct (Ia) or of the common bile duct and main hepatic ducts (Ib); type II, one or more cystic diverticula of the common bile duct; type III, focal dilatation of the distal common bile duct in the papillary region into which the pancreatic ducts drain (also called choledochocele); type IV, multiple dilatations of the intra- and extrahepatic (IVa) or of only the extrahepatic (IVb) bile ducts; and type V, Caroli disease (segmental ectasia of the large intrahepatic ducts throughout the liver).
Fig. 9.11 a,b Type 1 choledochal cyst in a 1-month-old boy. a Ultrasound shows dilatation of the common bile duct. b Cholangiopancreatography performed during surgery shows the dilatation of the common bile duct (arrow). The intrahepatic bile ducts are visible because of the reflux of contrast (open arrow). Note the poor collimation during surgery.
Fig. 9.12 a,b Thirteen-year-old girl with chronic upper abdominal pain. a Ultrasonography shows a fusiform dilatation of the extrahepatic bile duct and choledochal duct (arrow). b Mild dilatation of the central intrahepatic bile ducts (arrow). These findings are consistent with choledochal cyst, Todani type I.
Fig. 9.13 a–c Eleven-year-old girl presenting with abdominal distention and upper abdominal pain. a Abdominal ultrasound shows a grossly dilated common bile duct and intrahepatic bile ducts. b Axial T2-weighted magnetic resonance (MR) imaging shows the dilated common bile duct (arrow) and intrahepatic bile ducts (open arrows). c Coronal T2-weighted MR imaging shows the extent of the grossly dilated common bile duct. The imaging findings are in keeping with a Todani type IV choledochal cyst. During surgery, a cyst with a volume of approximately 1,700 mL was resected.

With US, the location and degree of bile duct dilatation can be easily depicted. Sludge or bile stones can be identified by bile stasis in the dilated ducts. In type V choledochal cysts (Caroli disease), the kidneys should be examined as well because this type is often associated with autosomal-recessive polycystic kidney disease ( Fig. 9.14 ). Pathognomonic for Caroli disease is the so-called central dot sign ( Fig. 9.15 ), which is the result of fibrovascular bundles, consisting of portal vein and hepatic artery branches, crossing the dilated choledochal cysts. Although originally described on CT, this sign is well visualized on US.

Fig. 9.14 a,b One-day-old boy with antenatally diagnosed liver cysts and enlarged kidneys. a Ultrasonography (US) of the liver directly after birth shows multiple fusiform and cystic dilatations of the intrahepatic bile ducts (Todani type V choledochal cysts). One of the cysts shows the “central dot” sign, which can be explained by the portal fibrovascular bundle surrounded by the dilated bile duct (arrow). b US of the kidneys shows extremely enlarged kidneys with diffusely increased echogenicity, absent corticomedullary differentiation, and multiple tiny cysts, characteristic of polycystic kidney disease (Caroli disease).
Fig. 9.15 a,b Central dot sign in a 7-year-old boy with known Caroli disease. b Color Doppler shows flow within the central dot.

The differentiation of a choledochal cyst ( Fig. 9.16 a–c) from a simple hepatic cyst, hepatic abscess, or pancreatic pseudocyst is sometimes difficult. Additional imaging consists of either endoscopic retrograde cholangiopancreatography (ERCP), which can be performed only in specialized centers by well-trained gastroenterologists and allows intervention, and/or magnetic resonance cholangiopancreatography (MRCP), which can be performed on all modern MR scanners, although sedation may be necessary ( Fig. 9.16 d, e; Video 9.16).

Fig. 9.16 a–e Type IVb choledochal cyst in a 4-year-old girl. a Ultrasound (US) of the liver shows dilatation of the common bile duct. b US of the liver shows intrahepatic dilatation of the bile ducts in the left and right liver lobes. c T2-weighted axial magnetic resonance imaging shows dilatation of the common bile duct (arrow). d Endoscopic retrograde cholangiopancreatography (ERCP) shows the abrupt change in caliber of the intrahepatic bile ducts. e Magnetic resonance cholangiopancreatography (MRCP) also shows the abrupt change in caliber of the intrahepatic bile ducts (arrow), but the resolution is less and intervention is not possible. Note the presence of ascites (open arrow) (see Video 9.16).


Congenital Portosystemic Shunts

Congenital portosystemic shunts are rare congenital anomalies that are mostly detected on US. The children can present with abnormal liver tests, elevated blood ammonia, and/or serum bile acid levels, or the shunt can be found incidentally on US. A portosystemic shunt can be intrahepatic ( Fig. 9.17 ), in which case there is a connection between a portal vein and either a hepatic vein or the inferior caval vein, or extrahepatic, in which case the portal trunk or a branch of it is in direct contact with the inferior caval vein. Extrahepatic portosystemic shunts are classified according to Abernethy. Type I consists of an atretic portal vein with the splenic and superior mesenteric veins terminating either separately in the inferior vena cava (type Ia) or as a common venous trunk (type Ib; Fig. 9.18 ). In Abernethy type II, there is a normal or hypoplastic portal vein with partial shunting into the inferior vena cava.

Fig. 9.17 a–c Nine-day-old boy with Down syndrome, known to have an association with congenital portosystemic shunt. a A congenital portosystemic shunt is detected as an incidental finding on screening abdominal ultrasonography (US). b Color Doppler US shows the congenital portosystemic shunt between the left portal vein and the middle hepatic vein. c Duplex US shows a turbulent flow pattern.
Fig. 9.18 a,b Eleven-year-old boy presenting with chronic upper abdominal pain. a Gray scale ultrasonography (US) shows a direct connection (arrow) between the portal vein (PV) and the right hepatic veins (RHV), consistent with an Abernethy type Ib congenital portosystemic shunt. b Color/duplex Doppler US shows flow in the shunt.

Intrahepatic portosystemic shunts can regress spontaneously before the age of 2 years, but if they persist, intervention may be needed. Long-term consequences of these shunts are the development of liver tumors (see later section on focal nodular hyperplasia), hepatic encephalopathy, hepatopulmonary syndrome, and pulmonary hypertension.



9.3.2 Infection



Hepatitis

Hepatitis is an inflammation of the liver. The most common cause is viral infection, but hepatitis can also be a result of autoimmune disease, metabolic disorders, or drug use. In the acute phase, imaging plays no significant role other than to rule out other diseases. The role of imaging is the follow-up of patients with hepatitis, in which case the interest lies in the detection of cirrhosis, portal hypertension, and tumors (especially hepatocellular carcinoma after hepatitis caused by hepatitis B virus or hepatitis C virus; Fig. 9.19 ).

Fig. 9.19 a–d Fifteen-year-old boy with autoimmune hepatitis. a Note the coarse aspect of the liver, in keeping with cirrhosis. b Doppler ultrasound shows decreased flow in the portal vein, in keeping with portal hypertension. c In the liver hilum, cavernomatous transformation is seen (arrow). d T1-weighted magnetic resonance imaging after gadolinium confirms the presence of cavernomatous transformation.


Pyogenic Abscess

Although relatively rare in the Western world, pyogenic liver abscesses are the most frequent abscesses encountered in children. The most common pathogen is Escherichia coli ( Fig. 9.20 and Fig. 9.21 ; Video 9.21). There is a well-known relation between appendicitis and the formation of liver abscesses; however, with the improved detection of appendicitis, this cause is decreasing. The most common pathways of infection are through the biliary tract and the portal system. Also, penetrating trauma can be the cause of abscess formation ( Fig. 9.22 ).

Fig. 9.20 Three-year-old boy with a liver abscess, which was treated with percutaneous drainage and intravenous antibiotics. Culture showed Pseudomonas aeruginosa, Escherichia coli, and Streptococcus milleri.
Fig. 9.21 a–c Thirteen-year-old boy presenting with persistent fever after visiting Indonesia. a Ultrasonography (US) shows a large heterogeneous mass with cystic components in the right liver lobe (arrow). b Axial T1 fat-saturated (THRIVE, T1W high-resolution isotropic volume examination) magnetic resonance (MR) image after the intravenous administration of contrast confirms the presence of a heterogeneously enhancing, multiloculate abscess in the right liver lobe. c A percutaneous drain has been placed in the abscess under US guidance (arrows), and pus has been aspirated. The US and MR imaging characteristics are consistent with a bacterial liver abscess, which was confirmed by culture of the aspirate (see Video 9.21).
Fig. 9.22 a–c Twenty-six-week-old premature neonate. a An umbilical venous line has been inserted. Note the small amount of gas around the tip of the line (arrow). b Ultrasonography reveals a lobulated hypoechoic lesion, in keeping with abscess formation. c A lineogram shows the relation between the tip of the umbilical venous line and the abscess (Image courtesy of A. Paterson).

On US, a liver abscess usually appears as a rounded or ovoid hypoechoic lesion, but it can have a heterogeneous appearance, as well. The wall may be thick and irregular. Septa and debris can be encountered. Less commonly, pyogenic microabscesses are encountered ( Fig. 9.23 ). Although not pathognomonic, a diffuse pattern is seen in Staphylococcus aureus infection, and a clustered pattern is seen in E. coli infection.

Fig. 9.23 Ten-year-old girl with known tuberculosis. Ultrasound shows a microabscess caused by the tuberculosis infection.


Fungal Infections

Fungal hepatic infections are characterized by the presence of numerous microabscesses (often also present in the spleen). They are encountered in children with hematologic malignancies or a compromised immunologic system. The most common causative agent is Candida albicans ( Fig. 9.24 ). On US, four patterns have been described: wheel within wheel, bull’s-eye, uniformly hypoechoic, and focally echogenic.

Fig. 9.24 a,b Eight-year-old girl with persisting fever and aplasia. a Ultrasonography shows multiple hypoechoic lesions (arrows), in keeping with microabscesses. b With the use of a high-frequency linear probe, a bull’s-eye configuration is clearly seen within the microabscess. This patient also had splenic involvement.


Parasitic Infections

The most common parasitic infection of the liver is due to Entamoeba histolytica, and infection of the liver is actually the most common extraintestinal presentation of this infection. US does not discriminate between a pyogenic abscess and an Entamoeba abscess. However, on aspiration of the abscess, the typical chocolate-colored pus can be encountered.


Hydatid or echinococcal cysts are caused by infection with Echinococcus granulosus, which is endemic around the Mediterranean but can also be encountered in areas where sheep are bred. On US, a purely cystic lesion may be seen, but often daughter cysts and/or calcification of the cyst wall is encountered. A pathognomonic finding is the so-called water lily sign, which is seen if the endocyst becomes detached from the outer pericyst ( Fig. 9.25 ).

Fig. 9.25 a,b Thirteen-year-old girl with an echinococcal cyst. a Note the water lily sign (arrow). b Interventional radiologic treatment consists of percutaneous evacuation of the cyst contents. This is a safe and effective method for the percutaneous treatment of multivesicular echinococcal cysts with or without cystobiliary fistulas that contain nondrainable material.


Cholecystitis

Cholecystitis is relatively rare in young children, but it becomes more common with increasing age when related to cholelithiasis. Acalculous cholecystitis also occurs, but usually only in critically ill children after trauma, major surgery, or burns, or during sepsis. On US, the gallbladder is typically enlarged and tender, with thickening of the wall. Pericholecystic fluid may be seen, and gallstones may be present ( Fig. 9.26 ). Cholecystitis should be distinguished from hydrops of the gallbladder. In the latter, the distended gallbladder lacks wall thickening, and patients are usually not as ill as in cholecystitis. Isolated gallbladder wall thickening without other signs of cholecystitis does occur in children with ascites and hepatitis/cholangitis.

Fig. 9.26 a–c Eighteen-day-old boy with right upper quadrant abdominal pain and fever. a Ultrasound (US) shows a thickened wall of the gallbladder (arrow). A collection adjacent to the gallbladder is seen (asterisk). b Sagittal US shows the elongated aspect of the abscess adjacent to the gallbladder. c Percutaneous drainage of the gallbladder was performed under general anesthesia. A 9F pigtail catheter (arrow) was placed.


Infectious Cholangitis

Infectious cholangitis occurs in children and usually has a bacterial origin, although viral, fungal, and parasitic infections are also possible, especially in the immune-compromised host. Infectious cholangitis is often associated with congenital or immune-related bile duct abnormalities, surgically corrected biliary atresia (Kasai procedure; Fig. 9.27 and Fig. 9.28 ), liver transplant, and certain immunodeficiency states. Therefore, the primary goal of US when infectious cholangitis is suspected is to search for anatomical abnormalities and/or obstruction of the biliary tract.

Fig. 9.27 a–c Nine-month-old girl with a history of biliary atresia and a Kasai procedure (hepatic portoenterostomy), presenting with fever and upper abdominal pain. a Ultrasonography shows irregular, dilated intrahepatic ducts and inhomogeneous liver parenchyma (arrow). b, c Axial turbo spin echo (TSE) T2-weighted magnetic resonance (MR) images illustrating the irregular, dilated intrahepatic bile ducts and increased periportal echogenicity, suspicious for ascending cholangitis (arrows).
Fig. 9.28 a–d Nineteen-year-old girl with a history of biliary atresia and a Kasai procedure (hepatic portoenterostomy), now presenting with sepsis and cholangitis. a Ultrasonography shows inhomogeneous liver parenchyma with dilated intrahepatic bile ducts and periportal echogenicity (arrow). b Furthermore, a fluid collection is seen ventral to the liver (arrow). c Coronal multiplanar reconstruction of a computed tomographic scan of the abdomen shows massive splenomegaly (asterisk), irregular dilatation of the biliary tree (arrows), and a complex, multiloculate fluid collection with the suggestion of a connection with the biliary tree (bilioma, open arrow). d Maximum intensity projection reconstruction of a respiration-triggered 3D turbo spin echo T2-weighted sequence also shows the irregular dilatation of the biliary tree (open arrow) and the close relation of the biliary tree to the biloma (closed arrow). Furthermore, ascites is visible surrounding the liver.


9.3.3 Acquired Biliary Pathology



Chole(docho)lithiasis

Gallstones are relatively uncommon in children, with a reported prevalence of up to 1.9%. They are more frequently detected in asymptomatic children because of the more widespread use of US. Chole(docho)lithiasis may be idiopathic ( Fig. 9.29 ), but in neonates and young infants it is often associated with sepsis, the use of diuretics, or total parenteral nutrition. In older children, gallstone formation may be related to obesity (an increasing problem in the pediatric age group; Fig. 9.30 ), sickle cell disease ( Fig. 9.31 ), hemolytic anemia, cystic fibrosis ( Fig. 9.32 ), and disease of the small bowel.

Fig. 9.29 a,b Ten-month-old boy presenting with jaundice. a Ultrasound shows choledocholithiasis, with stones in the common bile duct. Note the acoustic shadow (arrow) in the gallbladder (open arrow). No underlying cause was found. b Endoscopic retrograde cholangiopancreatography (ERCP) was performed to remove the stones (arrow) from the common bile duct.
Fig. 9.30 a,b Obese 15-year-old girl with colicky right upper abdominal pain. a Ultrasound shows multiple gallstones (arrow). b T2-weighted magnetic resonance imaging shows cholelithiasis (arrow).
Fig. 9.31 Seventeen-year-old asymptomatic boy with sickle cell disease. On routine abdominal ultrasound, multiple gallstones are seen within the gallbladder.
Fig. 9.32 Twelve-year-old girl with cystic fibrosis. On routine abdominal ultrasound, multiple gallstones are seen (arrow).

On US, gallstones will appear as echogenic foci with or without acoustic shadowing ( Fig. 9.33 and Fig. 9.34 ). Gallstones are calcified in approximately 50% of cases, particularly if associated with a hemolytic disorder. When located in the gallbladder, they often change in position with gravity. In the biliary tree, gallstones may cause biliary dilatation due to obstruction, which in most cases can be easily visualized on US ( Fig. 9.35 and Fig. 9.36 ). The differentiation of biliary sludge from small, nonshadowing gallstones may be difficult ( Fig. 9.37 ).

Fig. 9.33 Thirteen-year-old boy with colicky right upper quadrant abdominal pain. Ultrasound shows numerous gallstones filling the gallbladder. Note the acoustic shadow behind the stones (arrow).
Fig. 9.34 a,b Sixteen-year-old girl presenting with colicky upper abdominal pain. a Ultrasound shows multiple echogenic foci (arrow) with acoustic shadowing in the gallbladder. b Axial view of the same patient.
Fig. 9.35 a,b Eleven-year-old girl with colicky upper abdominal pain. a Transverse ultrasound (US) of the pancreas shows an echogenic focus (arrow) in the intrapancreatic part of the dilated choledochal duct, consistent with obstructing choledocholithiasis. b Longitudinal US shows a dilated choledochal duct (arrow).
Fig. 9.36 a–c Eleven-year-old girl with jaundice and abdominal pain. a Ultrasound shows multiple gallstones in the gallbladder (arrow). b An impacted gallstone is shown in the distal common bile duct (arrow). c Endoscopic retrograde cholangiopancreatography (ERCP), performed to remove the gallstone, shows the location of the distal gallstone (arrow).
Fig. 9.37 Three-year-old boy admitted to the pediatric intensive care unit. Note the multiple echogenic reflections in the gallbladder. On follow-up, these resolved spontaneously, in keeping with sludge.

In children treated with ceftriaxone, pseudochole(docho)lithiasis, as a result of biliary precipitation, can be encountered. In these children, follow-up US, after the discontinuation of treatment, will show resolution of the pseudochole(docho)lithiasis ( Fig. 9.38 ).

Fig. 9.38 a,b Nine-year-old girl treated with ceftazidime. a On abdominal ultrasound, hyperechoic structures with acoustic shadowing are seen (arrow). b Five weeks later, after the discontinuation of ceftazidime treatment, the precipitated bile has disappeared.

In cases of symptomatic chole(docho)lithiasis, the surgical technique of choice is laparoscopic cholecystectomy. With this new surgical technique, new complications are encountered, the most important of which is damage to the biliary tree. There are four different types of injury, which can be classified as follows:




  1. Type A: leakage of the cystic duct or peripheral intrahepatic biliary tract;



  2. Type B: leakage from the common bile duct without the presence of a stricture;



  3. Type C: stricture of the common bile duct without leakage;



  4. Type D: complete transsection of the common bile duct with or without resection of a section of the common bile duct ( Fig. 9.39 ).

    Fig. 9.39 a–c Sixteen-year-old girl with persistent abdominal pain and fever after laparoscopic cholecystectomy. a Ultrasound shows a dilatation of the proximal common bile duct (arrow), which could not be visualized more distally. b Ascites is present. c Percutaneous transhepatic cholangiography shows a complete disruption of the common bile duct (arrow), with leakage of contrast into the peritoneal cavity (open arrow).

In these postsurgical patients, US should be used to detect intraperitoneal fluid collections, especially around the liver hilum, and dilatation of the biliary tree.

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Jun 9, 2020 | Posted by in ULTRASONOGRAPHY | Comments Off on 9 Liver and Biliary System
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