Paediatric liver ultrasound: a pictorial essay

Abstract

Ultrasound scan is a painless and radiation-free imaging modality and, therefore, it is widely considered the first-choice diagnostic tool in the setting of hepatopathies in paediatric patients. This article focuses on the normal ultrasound anatomy of the liver in neonatal and paediatric age and reviews the ultrasound appearance of the most common diffuse and focal liver affections.

Keywords: Cholestasis; Diffuse hepatopathies; Focal liver lesions; Liver; Paediatric; Ultrasound.

Fig. 1

Schematic overview of segmental anatomy of the liver. Commonly, segments are identified following portal and venous branches ramifications

Fig. 2

US study of the liver: longitudinal and transverse scan along the midline (a, b) show the left hepatic lobe (segments II and III) separated from segment I (close to the inferior vena cava, IVC) and the left portal vein with its feeding branches for segments II, III and IV; in the oblique subcostal scan (c) there are right, middle and left hepatic veins which separate segments VII, VIII, IV and II; longitudinal scan along hemiclavear line (d) shows segments VII and VI; oblique subcostal scans (e, f) show right portal vein separating segments VIII and V

Fig. 3

US study of the liver, longitudinal and oblique scans: normal hepatic echostructure is characterised by homogenous low-to-intermediate echoes similar to the adjacent renal cortex; there are also tubular anechoic structures representing intrahepatic veins (arrows) and portal vein branches (arrowheads)

Fig. 4

US study of the liver: longitudinal scan along the right hemiclavear line is commonly used to measure the longitudinal diameter of the right hepatic lobe

Fig. 5

US of the liver, colour-Doppler study of the portal vein at the hilum. Portal flow is usually directed towards the liver, with normal mean velocity of 15–18 cm/s

Fig. 6

US of the liver with colour-Doppler (a, b) and colour-pulse-Doppler (c) study in a newborn depicts patent ductus venosus (with hepatofugal flow in blue)

Fig. 7

US of the liver, oblique scan in patient affected by acute hepatitis: there is an increase of hepatic volume and slight decrease of echostructure, while portal branches wall appears brighter

Fig. 8

US of the liver, longitudinal and oblique scans (a–d): the echogenicity of the liver is particularly bright, especially when compared to the adjacent renal cortex (c, d); moreover, there is blurred appearance of intrahepatic vessels walls and loss of diaphragmatic profile

Fig. 9

US of the liver, longitudinal, axial and oblique scan: there is hyperechogenic liver parenchyma (particularly when compared to the cortex of right kidney) with quite well-defined area of relatively hypoechogenicity (a, b) due to fat sparing-area; in the right figure (c) there is a geometrical shaped bright area which does not cause any mass effect and is therefore in keeping with focal hepatic steatosis

Fig. 10

Abdominal US study shows changes in hepatic cirrhosis, with evidence of volume decrease of the right lobe, irregular margins and roughly heterogeneous echogenicity (coarse pattern) in the right (a) and left lobe (b)

Fig. 11

US evaluation in cirrhotic liver with colour-Doppler study: at the hilum, the portal vein is replaced by portal cavernoma, composed by many small tortuous vessels as consequence of portal hypertension and vein thrombosis

Fig. 12

Abdominal US in advanced cirrhotic condition shows hepatic changes do to regeneration process and fibrosis (a, b), with also ascites, that is identified as anechoic fluid around the perihepatic space (star)

Fig. 13

Elastography of cirrhotic liver allows to evaluate stiffness of the parenchyma, which is related to the degree of fibrosis, as it affects the wave velocity measured by the probe

Fig. 14

US study of the liver in patient with cystic fibrosis shows diffuse echostructure changes with alternation of hypoechoic and hyperechoic areas

Fig. 15

US of the liver, oblique B-Mode imaging and colour-Doppler study at birth (upper line), at 1 month (central line) and at 3 months (lower line): there is a large heterogeneous mass, measuring about 20 mm, mostly iso-hypo-echoic, with internal anechoic tubular structures. Colour-Doppler images shows internal vessels characterised by both arterial and venous flow. At follow-up, B-mode evaluation shows slight reduction of diameter with increase of the internal anechoic necrotic component. Moreover, colour-Doppler tool demonstrates significant reduction and finally disappearing of internal vascular flow. These features were in keeping with the diagnosis of focal hepatic haemangioma

Fig. 16

US study of the liver, longitudinal and transverse B-mode images (a, b) and longitudinal colour-Doppler scans (c): there is a well-defined large mass, mostly iso-echoic, showing internal and peripheral vascular flow at colour-Doppler study. This latter takes a spoke-wheel-like appearance which is typical for focal nodular hyperplasia

Fig. 17

US study of hepatic adenoma with B-mode and colour-Doppler images: there is a well-defined large hyperechoic mass, with some internal anechoic areas, which shows peripheral and internal vessels (a, b)

Fig. 18

Ultrasonographic images of hepatic hepatoblastoma: there is an ill-defined heterogeneous mass, involving almost completely the right lobe, which shows hyper- and isoechoic areas (a–c); many internal vessels are identified at colour-Doppler image (d)

Fig. 19

Hepatocarcinoma at US B-Mode and Doppler images (a, b) and axial computed tomography and contrast-enhanced computed tomography images (c, d). At US the tumour appears as large heterogeneous lesion that bulges the liver surface, with significant internal vascular flow (a, b). Computed tomography images show large lesion with hyperdense components at un-enhanced scan (c), which demonstrates heterogeneous enhancement (d)

Fig. 20

US study (a, b) and computed tomography axial scans venous phase (c) of amoebic abscess: there is a large well-defined lesion involving VII/VIII segments, which shows internal hypo and anechoic areas at US. Computed tomography scans demonstrates internal fluid component with only enhancement of the irregularly thick peripheral wall

Fig. 21

US study of the liver demonstrates the presence of roundish hypo- anechoic area, probably due to parenchymal hematoma caused by displaced UVC (a–c). Frontal abdominal radiography of a newborn showing the UVC ending at the level of right portal vein (d)

Fig. 22

Schematic overview of choledochal cyst (Todani’s classification) Modified from Soares et al. [44]

Fig. 23

US study of choledochal cyst type I shows fusiform dilatation (a) of extrahepatic bile duct measuring 8.4 mm (b)

Fig. 24

US study of the liver with B-mode (a) and colour-Doppler (b) in a newborn with biliary atresia shows hyperechoic tissue (arrows) just near to the hepatic hilum

Fig. 25

US study of the liver with B-Mode and power Doppler modalities in a newborn with biliary atresia: there is hepatic arterial flow extending to the hepatic surface (subcapsular flow)