1
Q
Describe the Liver and its location
A
- It is the largest solid organ in the body.
- Intraperitoneal (inside the peritoneum and covered by a capsule, Glisson’s)
- Located in the RUQ (occupies a major portion of the right hypochondrium)
- Epigastrium (extends inferiorly)
- Left Hypochondrium (lateral into the left hypochondrium)
2
Q
Describe the shape of the Liver
A
- Shape depends on patient’s body habitus (or morphotype)
a. Irregular
b. Hemispheric
c. Wedge-shaped
3
Q
What is the weight of the Liver?
A
- The exact weight of a normal liver in adult women is 1,200g
- The exact weight of a normal liver in adult men is 1,600g
- The weight of the liver to total body weight is approximately 1/36th for an adult compared to approximately 1/18th for an infant
4
Q
Differentiate the Right Lobe of the Liver with the Left Lobe
A
- Right Lobe is 2 to 3 times larger than the Left Lobe
- Along the midclavicular line, the normal longitudinal measurement of the Right Lobe is 13cm or less.
- The greatest transverse portion = 20 to 22.5cm
- The greatest AP measurement = 10 to 12.5cm
- The greatest length on the right surface = 13 to 15.5cm
*Obtaining liver measurements in the sagittal section will help detect Hepatomegaly (more than 17cm)
5
Q
What is the Caudate and Right Lobe Ratio?
A
- Subcostal in true transverse plane
- Less than 0.65cm
6
Q
Describe the Perihepatic Relationships
A
- Diaphragm superior, anterior and posterior
- Right Kidney indents posterior right lobe
- IVC posterior
- Visceral surface (inferior) in contact with abdominal organs
7
Q
What is Glisson’s Capsule?
A
- It covers the liver.
- It is composed of two adherent layers; an outer serous layer that is derived from the visceral peritoneum and inner dense, fibroelastic connective tissue layer.
- It is named after the British physician, anatomist and physiologist and pathologist Francis Glisson.
- It contain blood, lymphatic vessels and completely covers the liver
- It surrounds the liver and encases the Hepatic Artery, Portal Vein and Bile Ducts within the liver at the porta hepatis.
8
Q
What is Bare Area?
A
- It is a portion of the posterior surface of the liver without a peritoneal covering, this portion is in direct contact with the diaphragm.
- It represents an area where infection can spread from abdominal cavity to the thoracic cavity
9
Q
What is Fossa’s?
A
- These are indentations in the liver.
- Gallbladder
a. Posterior inferior liver
b. Contains the main lobar fissure - IVC
a. Contains part of the the IVC
b. Between the caudate lobe and bare area of the liver
10
Q
What are Fissures?
A
- These are groove or cleft in the liver in which structures run through
- Porta Hepatis ( is a fissure where the portal vein and hepatic artery enter the liver and the bile duct exits the liver.)
- Main Lobar Fissure
- Intersegmental
a. Right
b. Middle
c. Left - Each hepatic vein has fissure (canal) because they don’t want to crush the veins. Right, Left and Middle Fissure
11
Q
What is the Interlobar Fissure?
A
The Interlobar Fissure divides the liver into Right Lobe and Left Lobe.
12
Q
What is the Intersegmental Fissure?
A
The Intersegmental Fissure divides into Right Intersegmental Fissure (Anterior and Posterior segments) and Left Intersegmental Fissure ( Medial and Lateral segments)
13
Q
What is the Sonographic Landmark for Right Intersegmental Fissure?
A
Sonographic Landmark: Right Hepatic Vein
14
Q
What is the Sonographic landmark for the Left Intersegmental fissure?
A
The Sonographic Landmark for the Left Intersegmental Fissure is the Left Hepatic Vein/LHV; the ascending branch of LPV and inferiorly the ligamentum teres
15
Q
What is the Main Lobar Fissure?
A
- The Main Lobar Fissure divides the liver into Right and Left Lobes.
- A short segment seen the Gallbladder Neck and RPV (Right Portal Vein)
- Middle Hepatic Vein runs through fissure
16
Q
What is the Right Intersegmental Fissure?
A
- The Right Intersegmental Fissure divides the Right Lobe of the Liver into anterior and posterior segments.
- Right Hepatic Vein courses through it.
- Anterior Segment of the RT Lobe
- Posterior Segment of the RT Lobe
17
Q
What is the Left Intersegmental Fissure?
A
- The Left Intersegmental Fissure divides the Left Lobe of the Liver into medial and lateral segments.
- The Left Hepatic Vein courses through it.
- Medial Segment of the LT Lobe
- Lateral Segment of the LT Lobe
18
Q
What is the Fissure for the Ligamentum Venosum?
A
- It divides the caudate lobe from the lateral left segment.
- It contains the Ligamentum Venosum
- It contains the Hepatogastric Ligament
19
Q
What are the ligaments for?
A
- Ligaments tethers the liver to the following:
a. Diaphragm
b. Anterior abdominal wall
c. Lesser curve of the stomach
d. Retroperitoneum - Ligament visualization helps idetify lobar anatomy; accurate localization of lobar structures and perihepatic fluid collections.
20
Q
What it the Coronary Ligament?
A
- The Coronary Ligament connects the posterosuperior liver surface to the diaphragm.
- It consists of an anterior and posterior layer.
- These layers are continous on each side with the Right Triangular and Left Triangular Ligaments
- It defines the bare area of the liver.
21
Q
What is the Falciform Ligament?
A
- The Falciform Ligament is a broad, thin anteroposterior fold of the parietal peritoneum.
- It runs from anterior to posterior on the left lobe of the liver and ends with ligamentum teres.
- It originates from the midportion of the coronary ligament; extends from the coronary ligaments
- It extends from the liver to the abdominal wall between the diaphragm and umbilicus.
22
Q
What is the Ligamentum Teres?
A
- It is a round ligament.
- It is the fibrous cord resulting from the obliterated left umbilical vein
- It is the remnant of the fetal umbilical vein.
- It is located at the inferior liver margin.
23
Q
What is the Ligamentum Venosum?
A
- It is the remnant of the ductus venosus.
- It inserts into the left branch of the portal vein.
- It is a continuance of the ligamentum teres within the left intersegmental fissure on the superior, visceral surface of the liver.
- It is anterior to the Caudate Lobe most likely on the left.
24
Q
Describe the Anatomical Relationship of the Caudate Lobe
A
The Caudate Lobe is anterior to Ligamentum Venosum and posterior to IVC.
25
Explain the Fetal Circulation
- Umbilical vein carries oxygenated blood from placenta to fetus which ascends divides into two branches.
- The Left Branch joins the portal vein and enters the liver.
- The Right Branch, the ductus venosus flows directly into the IVC bypassing the liver.
- After birth, both veins close and exists as Ligaments.
- The Left Umbilical Vein becomes the Ligamentum Teres or Round Ligament.
- The Ductus Venosus becomes the Ligamentum Venosum.
26
What is the Gastrohepatic Ligament?
- It is also known as the Lesser Omentum.
- It is composed of two folds of visceral peritoneum.
- It originates on the undersurface of the liver, continuous with the Ligamentum Venosum.
- It courses caudally to attach to the lesser curvature of the stomach and to the first portion of the duodenum.
27
What is the Hepatoduodenal Ligament?
- The Hepatoduodenal Ligament surrounds the portal triad at the porta hepatis.
- It forms the anterior boundary of the epiploic foramen (Foramen of Winslow)
28
What is the Portal Triad?
The Portal Triad is composed of the Portal vein, Hepatic artery and Bile duct.
29
What is the Triangular Ligament?
- It is formed by the apposition of the upper and lower ends of the coronary ligament and extend from the diaphragm of the liver.
- The Right Triangular Ligament is attached to the border at the right extremity of the bare area and passes to the diaphragm.
- The Left Triangular Ligament is larger of the two and attaches to the superior surface of the left lobe where it lies anterior to the esophageal opening in the diaphragm.
30
Describe Liver Divisions
- Lobar divisions of the liver can be described as ANATOMIC based on the external landmarks and visceral surface of the liver or SEGMENTAL (FUNCTIONAL), based on internal landmarks and hepatic function.
31
What is the Anatomic Division of Liver?
- The Anatomic Division is based on external markings.
- It is a broad division that uses the Falciform Ligament to divide the liver into the right and left hepatic lobes classifies the Caudate and Quadrate Lobes as part of the right lobe.
- Anatomic Division divides the liver into:
a. Right
b. Left
c. Caudate
d. Quadrate
- Visceral liver surface: "H" configuration
32
What is the Anatomical Division of the Caudate Lobe?
The Caudate Lobe is interposed between the following:
a. IVC - posteriorly
b. Left Liver Lobe - anteriorly and superiorly
c. Main Portal Vein - inferiorly
d. Ligamentum Venosum - anteriorly
33
What is the Anatomical Division of the Quadrate Lobe?
- It is on the visceral surface.
- It is described as the medial segment of the Left Lobe.
- It is bounded by the following:
a. Porta Hepatis - posteriorly
b. Inferior Margin of the Liver - anteriorly
c. Gallbladder Fossa on the right - laterally
d. Fissure for the Ligamentum Teres - on the left
34
Describe the Right Lobe in the Anatomic Division
- The Right Lobe is 6 times larger than the left, occupies the right hypochondrium.
- It is separated from the Left Lobe by the Falciform Ligament.
- The anterior portion is marked by Falciform Ligament.
- The posterior surfaces are marked by 3 Fossae: the Porta Hepatis, the Gallbladder and the IVC.
35
Describe the Left Lobe of the Liver in the Anatomic Division
- It is situated in the epigastric and left hypochondriac regions.
- It is separated from the Right Lobe of the Liver by the falciform ligament on its anterior surface.
- It is on the visceral surface.
- The fissure for the Ligamentum Teres separates from the quadrate lobe.
- The fissure for the Ligamentum Venosum separates from the caudate lobe.
36
What is the Segmental or Functional Liver Division?
- The sonographic landmarks used to identify lobes and segments; sonograhphers evaluate and document the liver using internal landmarks.
- The liver is divided into three lobes and 4 segments based on blood supply and biliary drainage.
1. Right Lobe - containing an anterior and a posterior segment
2. Left Lobe - containing a medial and lateral segment
3. Caudate Lobe
37
Describe the Segmental or Functional Liver Division
- The Portal Veins run within the liver segments, INTRASEGMENTAL OR INTRALOBAR.
- Portal Veins divide the liver horizontally creating 8 segments.
- Hepatic Veins run between the lobes and segments, INTERSEGMENTAL OR INTERLOBAR.
- Hepatic Veins divide the liver vertically into four segments.
38
Describe the Segmental or Fuctional Liver Division
- The quadrate lobe is now the medial segment of the left lobe.
- The anatomic left lobe is now the lateral segment of the left lobe.
- The caudate lobe is considered a separate, distinct lobe.
39
Describe the Right Segmental or Functional Lobe.
- It divides into anterior and posterior lobes by the right intersegmental fissure.
- The sonographic landmark for the Right Intersegmental Fissure is the Right Hepatic Vein.
- Right Hepatic Vein runs through fissure.
- Anterior and posterior right portal veins runs through the lobes respectively.
40
Describe the Segmental or Functional Left Lobe.
- It divides into medial and lateral lobes by the Left Intersegmental fissure.
- The sonographic landmark for the Left Intersegmental Fissure are the Left Hepatic Vein, the ascending branch of the Left Portal Vein and more inferiorly the hyperechoic Ligamentum Teres.
- Left Hepatic Vein runs though fissure.
- Medical and lateral left portal veins runs through the left lobes respectively.
41
Describe the Segmental or Functional Caudate Lobe.
- It is separated from the left lobe by the ligamentum venosum.
- It is functionally distinct.
- It is not considered part of the right or left lobe, as it receives its blood supply from both the right and left portal radicles.
- it is posterior to the liver.
- The landmarks are the following:
a. Ligamentum Venosum - Anterior
b. IVC - posterior and appears on the right
c. Left Portal Vein - Inferior
42
What is the Caudate Process?
- The Caudate Process is a small elevation of the caudate lobe.
- It extends to the right and obliquely.
- It is a tongue-like projection located between the IVC and portal vein.
- It influences the distance between the IVC and Main Portal Vein.
43
What is Papillary Process?
- It is an anteromedial extension of the caudate lobe.
| - It can mimic a mass of a lymph node.
44
What is Couinaud's Liver Division?
- The division creates 8 functionally separate liver segments, counted in a clockwise fashion.
Caudate Lobe - Segment I
Left Lobe - Segment II-IV
Right Lobe - Segment V-VIII
- Division is based on the Hepatic Veins (Vertical division, 4 segments) and Portal Vein (Horizontal division) branches.
- Each of the eight segments has a central portal vein, hepatic artery and bile duct.
- Hepatic veins provide the boundaries of each segment.
45
What are the Superior Segments in Couinaud's Anatomy?
Segments VII, VIII, IVa and II
46
What is the Mid Liver in Couinaud's Anatomy?
The Mid Liver identifies the right and left portal veins branches that correspond with the horizontal boundary.
47
What are the Inferior Segments in Couinaud's Anatomy?
Segments VI, V, IVb and III
48
What is Segment I in Couinaud's Anatomy?
Segment I - Caudate lobe is situated posteriorly and is anterior to the IVC and separated from the left lobe by the ligamentum venosum.
49
What is Segment II in Couinaud's Anatomy?
Segment II - Lateral segment of the left lobe located above (superior) the portal plane and lateral to the Left Hepatic Vein
50
What is the Segment III in Couinaud's Anatomy?
Segment III - Lateral segment of left lobe located below (inferior) the portal plane and lateral to the Left Hepatic Vein
51
What is Segment IVa in Couinaud's Anatomy?
Segment IVa - Medial segment of the left lobe located above (superior) the portal plane and between the Middle Hepatic Vein and Left Hepatic Vein
52
What is Segment IVb in Couinaud's Anatomy?
Segment IVb - Medial segment of left lobe located below (inferior) the portal plane and between the Middle Hepatic Vein and Left Hepatic Vein. It includes the quadrate lobe.
53
What is Segment V in Couinaud's Anatomy?
Segment V - Anterior segment of right lobe located below (inferior) the portal plane and between the Middle Hepatic Vein and Right Hepatic Vein
54
What is Segment VI in Couinaud's Anatomy?
Segment VI - Posterior segment of right lobe located below (inferior) the portal plane and lateral to the Right Hepatic Vein.
55
What is Segment VII in Couinaud's Anatomy?
Segment VII - Posterior segment of right lobe located above (superior) the portal plane and lateral to the Right Hepatic Vein
56
What is Segment VIII in Couinaud's Anatomy?
Segment VIII - Anterior segment of right lobe located above (superior) the portal plane between the Middle Hepatic Vein and Right Hepatic Vein
57
What are the different liver variants?
- These include variations in shape, variations in lobe size, thinning of the left lobe, congenital absence of the left lobe, diaphragmatic indentations (pseudofissures), high posterior hepatodiaphragmatic interposition of the colon and situs inversus.
58
What is Riedel's Lobe?
Riedel's Lobe is a common variant which gives the impression of hepatomegaly. It is identified as a finger-like or a tongue-like projection of the Right Lobe that extends distally and may reach as far as the iliac crest. It is more common in women than in men.
59
What makes up the Liver Vasculature?
- It receives a double blood supply.
- The hepatic arterial blood is oxygen rich, and the portal venous blood is nutrient rich after it traverses the walls of the gastrointestinal (GI tract).
60
What is Portal Veins?
- Intrasegmental
- Provide nutrients to liver
- Caliber increases moving away from the diaphragm
- Highly echogenic thick walls
- Follow a horizontal path in the liver
61
What is Hepatic Veins?
- Intersegmental
- Drain blood from liver
- Caliber increases moving towards the diaphragm
- Thin walls, less defined
- Follow a longitudinal path in the liver
62
What is Porta Hepatis?
- "Mickey Mouse" appearance (BD on the right and HA on the left)
- It is a gate into the liver
- It is a fissure where the portal vein and hepatic artery enter the liver and the bile duct exits the liver
63
What is Portal Triad?
- The Portial Triad consists of:
a. Bile Duct - is ventral and lateral
b. Hepatic Artery - is ventral and medial
c. Portal Vein - is dorsal
- All of which are within the Hepatoduodenal Ligament
- At outer edge of liver lobule
64
What is the Liver Lobule?
- it is the basic funtional unit of Hepatic Lobes
- The Liver Parenchyma is made up of 50,000 to 100,000 individual lobules
- Lobules are hexagonal or cylindrical shape and about 0.8 to 2mm in diameter.
- It has 6 corners, each corner is a portal triad.
65
What does the Liver made of?
- The Liver contain the following:
1. Hepatocyte - the functional cells of the liver
2. Central Hepatic Vein
3. Sinusoids
4. Kupffer
5. Cells
6. Bile Canaliculi
7. Portal Triad
66
What are the Hepatocytes?
- Hepatocytes are the functional cells of the liver.
- Produces bile salts and released into bile canaliculi
- Releases substances into sinusoid blood
67
What are the Sinusoids?
- They are located between columns of hepatocytes.
- They are small capillaries that have a highly permeableendothelial lining located between the cellular plates.
- The sinusoids receive a mixture of portal venous and arterial blood.
80% portal vein blood and 20% hepatic blood
68
What is the Central Hepatic Vein?
- The Central Hepatic Vein are smaller units converge into larger veins and form hepatic veins.
- The Central Vein is created by converging sinusoids.
- It is in the middle of each lobule and flows into interlobular hepatic veins; blood drain into
- It is toxin-fee and rich in liver secretions.
69
What is the Bile Canaliculi?
- Between two layers of hepatocytes
- It is the smallest division of the biliary tract.
- Bile is separated from blood by row of hepatocytes.
- Carry bile to triad region at the outer edge of the liver lobule.
- Converge to form larger ducts.
70
What are the Kupffer Cells?
- Kupffer cells line the sinusoids.
- These are phagocytic.
- They belong to the reticuloendothelial system and function to remove foreign substances from blood such as bacteria and depleted WBC and RBCs.
71
Describe the Physiology of the Liver.
- It is an organ essential to life, as it performs more than 500 separate activities.
- These functions are carried out by three types of cells in the parenchyma:
a. Hepatocyte - which carries out most metabolic functions
b. Biliary Epithelial Cells - which line the biliary system, bile ducts, canaliculi and gallbladder
c. Kupffer Cells - which are phagocytic and belong to the reticuloendothelial system
- It is "an accessory organ of digestion".
72
What are the several activities perform by the Liver?
- It is a factory for many chemical compounds.
- It is a warehouse with short and long-term storage capabilities.
- It is a power plant producing heat.
- It is a waste disposal excreting waste.
- It a chemist regenerating tissue that has not been too severely damaged.
73
What are the different Liver Function Tests?
1. ALT/ Alanine Aminotransferase (SGPT)
2. AST/ Aspartate Aminotransferase (SGOT)
3. ALP / Alkaline Phosphatase (Alk Phos)
4. LDH/ Lactic Dehydrogenase
5. GGT (Glutamyl Transpeptidase) or GGTP
6. AFP / (a-Fetoprotein)
7. PT (Prothrombin Time)
8. Bilirubin
9. INR/ International Normalized Ratio
10. PTT/ Activated Partial Thromboplastin Time
11. Serum Albumin
12. Hepatitis Testing
74
What is ALT?
- Alanine Aminotransferase (SGPT)
- It is produced mostly by the liver.
- It is a specific indicator of hepatocellular damage.
75
What is AST?
- Aspartate Aminotransferase (SGOT)
- It is found in all tissues.
- It is increased with damage to heart and liver tissue.
76
What is ALP?
- Alkaline Phosphatase (Alk Phos)
- It is an enzyme found in the tissues of liver, bone, intestine, kidney, placenta; normally excreted in bile and an indicator of biliary obstruction.
77
What is LDH?
- Lactic Dehydrogenase
- It is an enzyme in all tissues.
- It is not used for liver evaluation because other enzymes values are more specific.
- It increases in hepatitis, cirrhosis and obstructive jaundice.
78
What is GGT?
- Glutamyl Transpeptidase or GGTP
- It is responsible for the transport of amino acid and peptide across cell membranes.
- It is found chiefly in liver, kidney and pancreas.
- It is the most sensitive indicator of alcoholism and to other liver diseases.
79
What is AFP?
- a-Fetoprotein
- It is a globulin (protein) formed in yolk sac and fetal liver.
- It is normally present only in trace amounts after birth.
- It is produced with primary carcinoma of the liver and certain types of testicular cancer.
80
What is PT?
- Prothrombin Time
- It is a test used to determine pathologic deficieny of clotthing factors due to either liver dysfunction or to absence of Vitamin K
- Normal 25 to 35 seconds
81
What is Bilirubin?
- It is formed in large part from heme of destroyed erythrocytes or red blood cells.
- Heme is converted to biliverdin.
- Unconjugated/indirect bilirubin is bound to albumin and transported to liver cells.
- The liver conjugates the bilirubin with glucuronic acid, making it soluble in water and becomes direct bilirubin.
82
Differentiate Conjugated Bilirubin and Unconjugated Bilirubin.
Conjugated Bilirubin
- Direct Bilirubin
- Water Soluble
- Most excreted in feces and urine
- Increased with increase destruction of red blood celss
Unconjugated Bilirubin
- Indirect Bilirubin
- Fat Soluble
- Most remains in blood
- Increased with obstructive liver disease and biliary tract obstruction
83
What is INR?
- International Normalized Ratio
- It is a type of calculation based on PT test results.
- Normal is less than 1.
- It measures time it takes for your blood to clot.
- A low INR result means your blood is not thin enough or coagulates too easily and puts you at risk of developing a blood clot.
- A high INR result means your blood coagulates too slowly and you risk of bleeding.
84
What is PTT?
- Activated Partial Thromboplastin Time
| - It is used to monitor patients response to anticoagulant therapy
85
What is Serum Albumin?
- It is the smallest protein molecule, it makes up the largest proportion of total serum protein.
- It is almost totally synthesized by the liver.
- It decreases with chronic liver disease.
- It increases with hemolysis.
86
What is Hepatitis Testing?
- For Hepatitis A, B and C
| - It determines if a patient has been exposed, infected or is a carrier
87
What are the Indications for Sonographic Evaluation?
- RUQ pain
- Abnormal Function Tests or LFTs
- Palpable Liver Edge
- Jaundice
- Fever
- Portal Hypertension
- Palpable Mass
88
What is the Sonographic Appearance of the Liver?
1. Echotexture
- Homegenous
- Fine to medium level echoes
2. Echogenicity
- Isoechoic or slightly hyperechoic compared to the right renal cortex
3. Hyperechoic ligaments and fissures
4. Portal Vein Walls - hyperechoic
5. Hepatic Vein walls - echogenic
89
Explain the Imaging Protocols
- Sagittal and Transverse images demonstration lobes and segments
- Sweeping liver thoroughly and completely: superior to inferior and right to left
90
What is the Image Protocol for Sagittal?
RT Lobe (RLL)
- Main Lobar Fissure and RPV
- Comparison with Right Kidney
- Lateral with Rib Shadow
LT Lobe (LLL)
- At IVC
- At Aorta
- At Caudate Lobe
- Lateral to Aorta
91
What is the Image Protocol for Transverse?
RT Lobe (RLL)
- Superior Lateral with RHV
- At Right RPV
- At Right Kidney
LT Lobe (LLL)
- At Hepatic Confluence
- At Lateral Liver edge
- At LPV and Caudate Lobe
92
What are the Artifacts?
1. Shadowing
- Ribs
- Ligamentum Teres
- Edges of portal veins and bile ducts
2. Mirror Image/ Mirror Artifact
- Liver tissue superior to diaphragm
Abdominal Sonography
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