3. Lobes of the Liver
• Right lobe: The right lobe of the liver is the largest
of the liver’s lobes. It extends the left lobe by a
ratio of 6:1. It occupies the right hypochodrium.
• Left lobe: The left lobe of the liver lies in the
epigastric and left hypochondriac region.
• Caudate lobe: The caudate lobe is a small lobe
situated on the posterosuperior surface of the left
lobe opposite the tenth and eleventh thoracic
vertebrae .
4. Couinaud’s hepatic segments divide the
liver into eight segments .
• The hepatic veins are the longitudinal
boundaries .
• The right and the left portal pedicles
arethe transverse plane.
5.
6. Hepatic Segmental Anatomy
• Segment Ⅰ the caudate lobe.
• Segment Ⅱand Ⅲ includes the
left superior and inferior lateral
segment.
• Segment Ⅳa and Ⅳb includes
the medial segment of the left
lobe.
• SegmentⅤ and Ⅵ are caudal to
the transverse plane .
• Segments Ⅶ and Ⅷ are
cephalad to the transverse plane.
7.
8. Superior lateral
segment
Inferior lateral
segment
Superior anterior
segment (right lobe) Caudate lobe
Inferior anterior segment
(right lobe)
Superior posterior
segment (left lobe)
Superior posterior
segment (left lobe)
→
→
→
→
→
Medial segment
10. Patient Position
The position of the patient for the general
abdominal scan is usually supine for the initial
images. The patient is then rolled into various
degrees of obliquity to better demonstrate the
biliary system, pancreas, liver, kidneys, or
spleen. If the scanning plane is oblique, the
sonographer should indicate the change of
position on the documented image without
specifying the exact degree of obliquity. The
same would apply if the patient were in a
lateral, upright, or prone position.
10
11. Transducer and Instrumentation Selection
Transducer
The upper abdomen is scanned with the highest-resolution
transducer possible for the size of the patient.
Use sector transducer
The transducer frequency depends on the size, muscle and fat
composition of the patient. Generally a 3-MHz transducer is
used on most normal sized adult patients, with variations of 2.25
to 7.5 MHz, depending on image resolution and beam
penetration through the deeper structures in the liver.
Most transducers today actually are multi-focal with multiple
frequencies available in one transducer; therefore, the liver may
be scanned with the lower frequency
The lower-frequency transducers are often necessary in patients
with fatty infiltration or cirrhosis of the liver.
11
12. Transducer and Instrumentation
Selection
• the sonographer must find the best
"window" on the patient's abdomen. The
window refers to the area which the
transducer may be angled to record the
majority of abdominal landmarks without
interference from the ribs, bowel, stomach,
or lungs.
13. Sectional Anatomy
• Ultrasound of the abdomen is generally performed
in at least two image planes,
• transverse and longitudinal
Prepared by Dr.Awad Elkhadir 13
14. The normal ultrasonoud of the Liver
• Basically homogeneous parenchyma of
the liver allows imaging of the neighboring
anatomic structures in the upper abdomen.
15. To assess the:
• Size
• Capsular contour (smooth, coarse, lobulated)
• Parenchymal echogenicity
• Vascularity
• Biliary tree
• Masses or collections
16. Size of the liver
• Size: To measure the size of the liver, use a
sagittal approach in the mid clavicular line.
Measure from the diaphragm to the inferior
border on B mode image. This can be very
subjective.
• Look at the lower edge of liver in relation to the
Rt kidney. It should finish half way down the
kidney.
• B mode image an enlarged liver will have
rounded borders.
17. Size of the liver
Liver size may be measured from the tip of
the liver to the diaphragm . Generally this
measurement is less than 15 cm, with 15
to 20 cm representing the upper limits of
normal.
Hepatomegaly is present when the liver
measurement exceed 20 cm.
19. Parenchymal echogenicity
The Normal attenuation of the liver parenchyma
Normal: Liver texture=homogeneous
Assessment of its size , configuration, homogeneity , and
contour
20. The liver texture is compared with the renal parenchyma.
The normal liver parenchyma should have a softer ,
more homogenerous texture than the dense medulla
and hypoechoic renal cortex.
21. Ultrasound can allow us
to visualize the portal
veins, hepatic veins ,
intrahepatic bile ducts .
Vascularity and Biliary tree
22. The portal venous system is
a reliable indicator of various
ultrasonic tomographic
planes throughout the liver.
Main portal vein
Right main portal vein
Left main portal vein
Vascular Supply: Portal veins
Intrahepatic Portal Vein Branches
• Right anterior superior left median superior
• Right anterior inferior left median inferior
• Right posterior superior left anterior inferior
• Right posterior inferior left lateral superior
23. Vascular Supply: Hepatic veins
The hepatic veins are divided into three components:
right,middle,and left. The right hepatic veins is the
largest and enters the right lateral
24. Distinguishing Characteristics of Hepatic and
Portal Veins
• The best way to distinguish
the hepatic from the portal
vessels is to trace their
points of entry to the liver.
The hepatic vessels flow into
the inferior vena cava,
whereas the splenic veins
and superior mesenteric vein
join together to form the
portal venous system.
25. Distinguishing Characteristics of Hepatic
and Portal Veins
• The walls of hepatic veins are thin-walled ,and the walls
of portal veins are brightly reflective veins
26. The hepatic veins are easily differentiated from bile
ducts and portal veins .
They are not surrounded by an echogenic wall
They originate close to the diaphragm , and can be
traced into the inferior vena cava
