Hepatobiliary and pancreatic imaging in children—techniques and an overview of non-neoplastic disease entities
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- Nievelstein, R.A.J., Robben, S.G.F. & Blickman, J.G. Pediatr Radiol (2011) 41: 55. doi:10.1007/s00247-010-1858-5
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Imaging plays a major role in the diagnostic work-up of children with hepatobiliary or pancreatic diseases. It consists mainly of US, CT and MRI, with US and MRI being the preferred imaging modalities because of the lack of ionizing radiation. In this review the technique of US, CT and MRI in children will be addressed, followed by a comprehensive overview of the imaging characteristics of several hepatobiliary and pancreatic disease entities most common in the paediatric age group.
Imaging of the paediatric hepatobiliary and pancreatic systems consists mainly of US, CT and MRI. All these techniques have undergone major technical developments in the last decades, leading to a substantial increase in their diagnostic applications and accuracy in children. Today, US and MRI have become the preferred imaging modalities over CT and conventional radiography (CR) as they avoid the use of ionizing radiation.
The radiologist dealing with hepatobiliary and pancreatic diseases in children should be familiar with its various manifestations specific for this age group. There are diseases that are almost exclusively found in children, such as congenital anomalies and certain types of tumours. On the other hand, the child may present with an entity also found in adults with similar imaging appearances (e.g., cholelithiasis and hepatic cirrhosis), although the causative agent may be different and again age-specific. Knowledge of all the clinical and imaging characteristics is pivotal for the choice of the best imaging modality or combination of modalities, but also for the recognition of the diseases affecting children.
In this review we will discuss the technique of US, CT and MRI of the paediatric hepatobiliary and pancreatic system. Furthermore, we will address the imaging characteristics of several non-neoplastic hepatobiliary and pancreatic disease entities most common in children.
US is the imaging modality of choice for initial evaluation of children with suspected hepatobiliary or pancreatic diseases for many reasons. It is a patient-friendly and radiation-free imaging modality that does not suffer from motion artefacts. The relative small size of the child and fat-free intra-abdominal content results in improved penetration of the sound waves compared to adults, increasing the image quality. Furthermore, the ubiquitous availability of high-frequency transducers allows for a better tissue differentiation and real-time evaluation of vascularisation (Doppler studies) and movements (e.g., peristalsis) is possible. Finally, the direct contact with the patient during the examination offers a unique opportunity to ask specific questions and perform additional physical examinations, emphasizing the role of the radiologist as a clinician.
Initially patients are scanned in the supine position after a (roughly 3 h) period of fasting. To visualize the entire liver and pancreas additional positions (e.g., lateral decubitus) and additional manoeuvres (forced inspiration, graded compression, introduction of water into the stomach) may be necessary.
Normal liver length in children 
Liver length in midclavicular line (cm)
Number of patients
Mean [standard deviation(sd)]
Limits of normal
Normal values of the pancreas in children 
Maximal AP diameter pancreas (sd) in cm
1 month–1 year
Optimal use of sonographic equipment is mandatory; to optimize imaging the frequency of the emitted sound waves should be as high as possible. Further optimization includes graded compression, optimal focus adjustments, compound imaging, adaptive image processing, harmonic imaging and in selected cases elastography or intravenous ultrasonographic contrast. Transient elastography is a relatively novel noninvasive method to detect and quantify liver fibrosis and/or cirrhosis . This technique is performed using a US transducer in combination with a vibrator. By using the pulse-echo US acquisition it becomes possible to follow the propagation of the vibrations transmitted toward the liver tissue from the vibrator and measure their velocities that are related directly to the tissue stiffness. Recent studies suggest that this technique provides an objective and reproducible measure of the liver stiffness with a good interobserver agreement [3–5].
The recent advances in multidetector CT (MDCT) have contributed to a substantial increase in its use and diagnostic accuracy, even in children. A major drawback of this development in MDCT, however, is the increasing use of ionizing radiation and, consequently, the risks of radiation-induced side effects of which the induction of secondary cancer is the most important. Therefore, MDCT should only be used when properly indicated (justification). Furthermore, if CT is indicated, the technique should be optimized in order to keep the radiation dose as low as reasonably achievable (ALARA).
Common indications for which MDCT is still used in children are trauma and staging of malignancies. Although for the latter MRI is increasingly validated and used (see below), CT still plays a role, especially when combined with FDG-PET. All other indications can usually be addressed by US and MRI. This is especially true for the characterization of liver lesions and the evaluation of the pancreaticobiliary system.
Guidelines for tube voltage (kVp) and effective tube current (mA) for 16-slice CT scanners 
16 × 1.25 mm
16 × 0.75 mm
16 × 0.75 mm
16 × 1 mm,M
Common indications for MRI are (the characterization of) liver and pancreatic tumours, inflammatory or infectious conditions and vascular malformations. As stated before, MRI is increasingly used for oncological indications, not only because of its excellent tissue contrast and resolution but also because of the promising advances in functional imaging techniques such as diffusion-weighted imaging (DWI) and MR-spectroscopy (MRS) . MR cholangiopancreatography (MRCP) has also proved to be very useful in children. Indications are choledochal duct malformations and posttraumatic, postoperative or postinflammatory changes of the pancreaticobiliary tree.
Guidelines for MR imaging of the liver and pancreas (1.5T, Achieva, Philips Healthcare, Best, The Netherlands). NSA, number of acquisitions
Flip angle (degree)
Slice thickness (mm)
Breath-hold spoiled gradient-echo (GRE) T1
Axial, sagittal and/or coronal
10 mm (liver)
10 mm (pancreas)
Breath-hold spoiled GRE T1 in-phase
7 mm (liver)
TE 6.9 ms (1.0 T)
7 mm (pancreas)
Breath-hold spoiled GRE T1 out-phase
7 mm (liver)
TE 3.45 ms (1.0 T)
7 mm (pancreas)
Respiratory-triggered (rt) turbo spin-echo (TSE) T2
7 mm (liver)
7 mm (pancreas)
Rt spoiled GRE T1
7 mm (liver)
7 mm (pancreas)
Breath-hold 3-D spoiled GRE T1 with fat saturation
4 mm (liver)
dynamic multiphase sequence after IV contrast agent
4 mm (pancreas)
Guidelines for MRCP (1.5T, Achieva, Philips Healthcare, Best, The Netherlands)
Flip angle (degree)
Slice thickness (mm)
Breath-hold spoiled GRE T1
Axial, sagittal and/or coronal
Rt TSE T2
Rt spoiled GRE T1
Breath-hold 3-D TSE T2 (thick slab)
nine slices with a radial acquisition and pancreatic head in centre
Rt 3-D TSE T2
Biliary atresia is a congenital obstruction of the intra- and/or extrahepatic bile ducts [13–15]. It is one of the causes of persistent neonatal jaundice and is two times more frequent in males. The overall incidence is approximately 1:15,000 births, but it is far more common in the Asian population. Children with biliary atresia may have similar clinical, biochemical and histological manifestations as neonatal hepatitis and, therefore, diagnostic imaging plays an important role in differentiating these and other causes of jaundice.
Choledochal cysts often present with cholestatic jaundice, although in older children the typical triad of abdominal pain, fever and obstructive jaundice may be present [22, 25]. The most common complication of choledochal cysts is an ascending cholangitis and/or pancreatitis, often caused by reflux of pancreatic secretions in the bile ducts due to the abnormal junction of common bile and pancreatic duct. Liver cirrhosis, portal hypertension and spontaneous cyst rupture are other reported complications. Children with choledochal cysts do have an increased risk of developing cholangiocarcinoma, especially over the age of 10 years. The incidence reported varies between 9% and 28% .
Developmental anomalies of the pancreas
Congenital anomalies of the pancreas include pancreas divisum, annular pancreas, agenesis of the dorsal pancreatic anlagen, ectopic pancreatic tissue, hereditary chronic pancreatitis and nesidioblastosis . Nesidioblastosis is persistence of the normal fetal state of the pancreas (diffuse proliferation and persistence of nesidioblasts). These cells secrete an excess of insulin causing hypoglycaemia. Neonatal cases of nesidioblastosis are characterized by diffusely increased echogenicity and increased size of pancreatic head, body and tail. Treatment is subtotal pancreatectomy.
Syndromes that can manifest with pancreatic pathology include: Beckwith-Wiedemann syndrome, Von Hippel-Lindau disease and autosomal-dominant polycystic kidney disease. Children and adults with Shwachman-Diamond syndrome and cystic fibrosis (CF) frequently present with pancreatic insufficiency. In the next section on hereditary disorders a separate paragraph is dedicated to the pancreatic and liver manifestations of CF.
CF is an autosomal-recessive disease caused by a gene defect encoding for the CF transmembrane conductance regulator (CFTR) . This abnormal chloride metabolism is manifested especially in the cells of exocrine glands, resulting in increased viscosity of the products of these cells. Affected are sweat glands, mucus producing cells in the tracheobronchial tree, intestinal tract, exocrine tissue of pancreas and the seminal vesicles in boys. In the liver CFTR is expressed only on the apical surface of the cells of the biliary epithelium, leading to dehydration of bile with obstruction of bile ducts. In patients with CF, liver and pancreas are gradually affected resulting in end-stage liver cirrhosis and pancreatic atrophy .
Liver in CF
Chronic liver disease is one of the major complications of CF . Significant liver disease is seen in 13–25% of children with CF . Liver disease typically develops in the first decade of life, with the incidence dropping rapidly after the age of 10 years. Histologically, three types of liver disease are seen in CF: steatosis, focal biliary fibrosis and multilobular cirrhosis.
The first direct ultrasonographic sign of cirrhosis is nodularity of the liver. Before the nodules themselves become visible indirect signs of nodularity should be looked for, such as undulating contours of the liver surface or undulating contours of the endothelial lining of the liver veins (Fig. 10). Gradually the liver atrophies and portal hypertension develops. A study comparing US with biopsy findings showed that abnormal ultrasonographic findings predict fibrosis and cirrhosis, but normal ultrasonographic findings do not exclude it . However, liver biopsy can be unreliable due to sampling errors caused by focal distribution of cirrhotic changes. Transient elastography may be an attractive alternative to noninvasively assess and follow-up CF-associated liver disease .
CT offers additional information but this does not justify its use as the initial imaging modality of choice. In patients with increased echogenicity CT may differentiate between steatosis and focal biliary fibrosis. Eventually malignant degeneration occurs but this is far beyond childhood. MRI can be considered as an alternative to US and CT, not in the least because it provides unique information of the biliary tree.
Pancreas in CF
Pancreatic involvement in children with CF is more frequent than liver disease . Plugging of pancreatic ducts with inspissated secretions is thought to play a major role in the pathogenesis. It results in exocrine insufficiency, with clinically apparent dysfunction in 85–90% of patients. Pancreatitis is a rare complication (1.2% of patients). The morphological abnormalities in the pancreas are caused by fat deposition and fibrosis. US is the initial modality of choice, showing an enlarged or small pancreas with increased echogenicity. Areas of decreased echogenicity represent fibrosis.
CT and MRI can demonstrate these changes to a better advantage but are time-consuming, expensive or involve radiation (CT). Although MRI is superior in demonstrating fatty infiltration, it cannot demonstrate small calcifications that can occur in CF.
Beckwith-Wiedemann syndrome (also called EMG syndrome) is characterized by congenital abdominal wall defects (exomphalos), macroglossia and pre- and postnatal overgrowth (gigantism) [36, 37]. Additional findings may include organomegaly (usually liver and kidney), hypoglycaemia, hemihypertrophy and genitourinary abnormalities. Five- to twenty-percent of these children will develop embryonal tumours (most commonly Wilms tumor or hepatoblastoma), or adrenal tumors. Most of these tumours will develop in the first years of life, usually younger than 4 years of age, although Wilms tumor may occur until 8 years of age.
Acquired biliary pathology
Although gallstones are relatively uncommon in children, their incidence has been increasing over the last decades. This is mainly due to the more widespread use of US with, as a consequence, gallstones more frequently detected in asymptomatic children. Furthermore, the increase in obesity in the paediatric age-group certainly plays a role. In a recent population-based study the reported prevalence of gallstones in children was 1.9% . Cholelithiasis may by idiopathic, but in the neonate and young infant it is often associated with sepsis, diuretics and total parenteral nutrition . In older children, gallstone formation may be caused by haemolytic anaemia (e.g., sickle cell disease), CF and small bowel diseases. Gallstones are calcified in approximately 50%, particularly if associated with haemolytic disorders.
Biliary tract infections do occur in children and are often associated with congenital or immune-related bile duct abnormalities, surgically corrected biliary atresia (Kasai procedure) (Fig. 5), liver transplantation and certain immunodeficiency states [39, 40]. Infectious cholangitis usually has a bacterial origin, although viral, fungal and parasitic infections are also possible, especially in the immune-compromised host. The primary goal of the radiological evaluation in (suspected) infectious cholangitis is to search for evidence of anatomical abnormalities (e.g., choledochal cysts) and/or obstruction of the biliary tract. US is the initial imaging modality of choice in children followed by MRCP.
A distinct type of cholangitis, increasingly found in children, is primary sclerosing cholangitis (PSC) . This is a chronic and usually progressive cholestatic liver disease of unknown origin, which can result in liver cirrhosis, portal hypertension and liver failure. PSC is associated with inflammatory bowel diseases (IBD); 70%–80% of patients with PSC have IBD, and conversely, up to 7% of patients with IBD will develop PSC . The diagnosis is based on clinical and typical imaging features, cholestatic biochemical profile and liver histology.
US plays a minor role in the evaluation of PSC. It may reveal intra- and/or extrahepatic bile duct dilatation. Furthermore, the liver parenchyma may show increased echogenicity and heterogeneity related to the cirrhosis. Splenomegaly and ascites can be seen in case of portal hypertension.
Diffuse liver disease
Liver cirrhosis does occur in children and is usually secondary to a wide variety of congenital and acquired diseases, such as biliary atresia, CF, congenital hepatic fibrosis, metabolic disorders, hepatitis and Budd-Chiari syndrome . It is characterized by widespread destruction of the liver parenchyma with fibrosis and regeneration in a focal nodular pattern (micro- and macronodules). Complications of cirrhosis are portal hypertension and hepatocellular carcinoma.
Although the above described characteristics of liver cirrhosis and its complications can also be demonstrated with CT, MRI is the preferred advanced imaging modality in children because of the lack of ionizing radiation. When performed, CT will show a normal-size or small liver with irregular margins and areas of decreased attenuation due to fatty infiltration. Contrast enhancement is heterogeneous and signs of portal hypertension can be demonstrated with CT as well. Hepatic scintigraphy usually does not play a role in imaging cirrhosis.
In children, portal hypertension is usually due to extrahepatic portal obstruction, including idiopathic cavernous transformation, intrinsic portal vein webs, portal vein thrombosis related to umbilical vein catheterization, postoperative complications and masses in the porta hepatis . It remains clinically silent until either splenomegaly is detected or upper GI bleeding occurs. The most common intrahepatic cause of portal hypertension is liver cirrhosis.
MRI and MR angiography (MRA) can be used to evaluate the portal venous system . Usually, standard T1- and T2-W imaging of the liver parenchyma will precede the post-gadolinium imaging and MRA of the hepatic vessels. In pre-contrast T1-W imaging the hepatic vessels will appear black, whereas they will be bright on contrast-enhanced T1-W imaging and MRA. Thrombosis of the portal vein can be identified as an intravascular filling defect on both pre- and post-contrast imaging, although this can be simulated by slow or stagnant flow. Identification of the varices and collateral pathways is usually possible. Although CT can demonstrate these issues with similar accuracy, MRI is again preferred because of the lack of ionizing radiation.
This is a rare entity in children caused by a hepatic venous obstruction. It is often idiopathic, but can be associated with hypercoagulable states, congenital venous webs (intrahepatic or caval), neoplasms, trauma and abdominal surgery . Children with Budd-Chiari syndrome usually present with rapid-onset abdominal distension and pain due to hepatomegaly and ascites.
CT and MRI are both accurate but not highly specific in identifying Budd-Chiari syndrome . Typical features include hepatomegaly with an enlarged caudate lobe, heterogeneous liver parenchyma, absent or narrowed hepatic veins, thrombus in the hepatic veins, intrahepatic venous collaterals, thrombosis or compression of the inferior vena cava and ascites (Fig. 19). MRA may demonstrate hepatic venous obstruction and collateral circulation, probably as accurately as Doppler US and angiography.
Acute and chronic inflammatory diseases of the pancreas in childhood cause significant morbidity and mortality [51, 52]. Acute pancreatitis is idiopathic in 23% of patients. Other aetiologies are trauma (22%), structural anomalies (15%), multisystem diseases (14%), drugs and toxins (12%) and viral infections (10%). US is the primary imaging modality for detection of pancreatic abnormalities and for exclusion of extrapancreatic disease . CT is widely used for further evaluation and MRI (including MRCP) is emerging as the modality of choice. ERCP is becoming an interventional modality. The aetiology of chronic pancreatitis includes CF, fibrosing pancreatitis, hereditary chronic pancreatitis and inborn errors of metabolism.
In case of blunt abdominal trauma, the liver is a commonly injured organ, especially in children because their ribs are more flexible [55–57]. The vast majority of blunt liver injuries in children are due to bicycle and pedestrian accidents. The most common mechanism is a child being struck by a car while cycling or crossing the road, although steering-column injuries also play a major role. In the neonate, a liver injury may be caused by a traumatic delivery or resuscitative effort. Liver injuries usually involve segments 6, 7 and 8, and may range from a minor tear of the capsule to a full-blown laceration with injury of the vascular supply and/or bile ducts of the liver. In more than 50% of patients the liver injury is associated with other upper abdominal injuries, especially injuries to the spleen. Currently, most blunt liver injuries are treated conservatively (up to 97% in children), and surgery or interventional radiology is only indicated in the haemodynamically unstable child or when conservative treatment fails.
Classification of blunt hepatic trauma 
Subcapsular haematoma <10% surface area, capsular tear <1 cm parenchymal depth
Subcapsular haematoma 10%–50% surface area, intraparenchymal haematoma <10 cm diameter, laceration 1–3 cm parenchymal depth and <10 cm length
Subcapsular haematoma >50% surface area or expanding, ruptured subcapsular or parenchymal haematoma, intraparenchymal haematoma >10 cm or expanding, laceration >3 cm parenchymal depth
Parenchymal disruption involving 25%–75% of hepatic lobe or 1–3 Couinaud’s segments within a single lobe
Parenchymal disruption involving >75% of hepatic lobe or >3 Couinaud’s segments within a single lobe, juxtahepatic venous injuries (retro hepatic vena cava, central major hepatic veins)
The role of MRI in the diagnosis and follow-up of liver injuries still has to be established. In the acute phase, the role of MRI will be limited, but in the follow-up MRI can be used for monitoring the liver lesions, especially in children in whom the radiation dose of CT is a concern. MRCP can be used to demonstrate bile duct lesions . Scintigraphy with 99m Tc IDA can be used to evaluate bile leaks.
The pancreas is vulnerable to blunt abdominal trauma because of its fixed retroperitoneal position. In children with blunt abdominal trauma, pancreatic damage occurs in 3–12% . Bicycle injuries are common and child abuse may result in pancreatic injuries in infants.
Classification of pancreatic trauma 
Minor contusion or superficial laceration without duct injury
Major contusion or laceration without duct injury or tissue loss
Distal transection or parenchymal injury with duct injury
Proximal (right of the superior mesenteric vein) transection or parenchymal injury involving the ampulla
Massive disruption of the pancreatic head
As illustrated in this review, imaging plays a major role in the diagnostic work-up of children with hepatobiliary or pancreatic diseases. US is almost always the first imaging modality of choice, followed by MRI. CT can be reserved for imaging trauma and staging of malignancies, although for the latter MRI is increasingly validated and used.
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