Surgery Lecture: Liver Anatomy

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Questions and Answers

What is the main reason why the right lobe of the liver is susceptible to damage?

Due to its proximity to the lungs. (correct)

Due to its proximity to the spleen.

Due to its proximity to the diaphragm.

Due to its proximity to the stomach.

What percentage of patients with amebic abscess are jaundiced?

75%

90%

22% (correct)

50%

What is the main function of the liver that is being referred to when discussing albumin?

Synthetic function (correct)

Metabolic function

Detoxification

Excretory function

What is the half-life of albumin?

15-20 days Signup and view all the answers

What is the significance of the decrease in albumin levels?

It indicates liver damage. Signup and view all the answers

What is the diagnostic test of choice for an amebic abscess?

CT Scan Signup and view all the answers

What is the significance of the International Normalized Ratio (INR)?

It measures the rate of conversion of prothrombin to thrombin. Signup and view all the answers

What is the characteristic finding of an amebic abscess on CT Scan?

Well-defined densities with lack of rim enhancement. Signup and view all the answers

What is the percentage of accuracy of serologic tests in diagnosing an amebic abscess?

92-97% Signup and view all the answers

What is the significance of the presence of trophozoites in the aspirate of an amebic abscess?

It is diagnostic of an amebic abscess. Signup and view all the answers

What is a common complication of portal hypertension?

Ascites Signup and view all the answers

What is the gold standard imaging study for liver diagnosis?

Triple-Phase CT Scan Signup and view all the answers

What is the characteristic of most liver tumors?

Hypervascular Signup and view all the answers

What is the Warren-Distal splenorenal shunt characterized by?

Portal flow to the liver is preserved Signup and view all the answers

Why is a tissue sample not typically required for liver diagnosis?

It is dangerous and may lead to bleeding or seeding of cancer Signup and view all the answers

What is observed in the early arterial phase of a Triple-Phase CT Scan?

Dye is in the hepatic artery Signup and view all the answers

What is observed in the early portal venous phase of a Triple-Phase CT Scan?

Dye is in the portal vein Signup and view all the answers

What is the purpose of a Triple-Phase CT Scan?

To differentiate one liver tumor from another Signup and view all the answers

What is the primary source of blood supply to the liver?

Portal vein Signup and view all the answers

What is the approximate percentage of blood supply to the liver from the hepatic artery?

25% Signup and view all the answers

What is the name of the imaginary line that divides the liver into right and left lobes?

Cantlie's line Signup and view all the answers

What is the name of the smallest functional unit of the liver?

Acinus Signup and view all the answers

Which of the following hepatic veins drains directly into the inferior vena cava?

Caudate lobe Signup and view all the answers

What is the name of the fibrous sheath that surrounds the liver?

Glisson's capsule Signup and view all the answers

Which segment of the liver is also known as the medial segment?

Segment IV Signup and view all the answers

What is the name of the veins that form the portal vein?

Superior mesenteric vein and splenic vein Signup and view all the answers

What is the percentage of the liver's blood supply that may arise from the superior mesenteric artery?

15% Signup and view all the answers

What is the name of the system that organizes the liver into functional units?

Rappaport's system Signup and view all the answers

What is the age range for Giant Hemangioma in females?

20-50 years old Signup and view all the answers

What is the characteristic feature of Focal Nodular Hyperplasia on CT scan?

Hypervascular lesion Signup and view all the answers

What is the symptom of Kasabach-Merritt syndrome?

Thrombocytopenia Signup and view all the answers

What is the size of a Giant Hemangioma?

> 10 cm Signup and view all the answers

What is the characteristic feature of Hemangioma on Ultrasound?

Hypoechoic or anechoic lesion Signup and view all the answers

What is the diagnosis for a complex cyst with intrahepatic ductal dilatation?

Malignant tumor Signup and view all the answers

What is the treatment for a symptomatic Hemangioma?

Resection or enucleation Signup and view all the answers

What is the characteristic feature of Hemangioma on CT scan?

Hypodense lesion Signup and view all the answers

What is the diagnostic test for Hemangioma?

Triple Phase CT Scan Signup and view all the answers

What is the characteristic enhancement pattern of Hemangioma on Triple Phase CT Scan?

Asymmetrical nodular peripheral enhancement Signup and view all the answers

Which of the following is a characteristic of a mucinous cystic neoplasm?

Contain bloody or chocolate-like fluid Signup and view all the answers

What is the recurrence rate for surgical fenestration of a simple hepatic cyst?

5-15% Signup and view all the answers

What is the most common risk factor for hepatocellular carcinoma (HCC)?

Viral hepatitis (B or C) Signup and view all the answers

What is the sensitivity of triple-phase CT scan in detecting liver lesions?

40-50% Signup and view all the answers

What is the purpose of indocyanine green clearance test?

To predict post-operative liver failure Signup and view all the answers

Which of the following is a characteristic of beta-catenin activated adenoma?

Has a pseudo-capsule Signup and view all the answers

What is the role of intraoperative ultrasound in liver resection?

To guide resection planes Signup and view all the answers

What is the response rate for transarterial chemoembolization (TACE) in hepatocellular carcinoma?

70-80% Signup and view all the answers

What is the indication for radiofrequency ablation?

Surgically inaccessible tumors Signup and view all the answers

What is the benefit of liver resection in hepatocellular carcinoma?

Improved 5-year survival rate to 70% Signup and view all the answers

Study Notes

Liver Anatomy and Blood Supply

The liver is the largest organ in the body, weighing 1500g, and located in the right upper abdominal cavity beneath the diaphragm and protected by the rib cage.
The liver receives the majority of its blood supply from the Portal Vein, which delivers 75% of the blood supply, and the remaining 25% from the Hepatic Artery.
The Portal Vein is formed by the confluence of the Superior Mesenteric Vein and Splenic Vein, and drains the splanchnic blood from the gastrointestinal tract.
Cantlie's line is an imaginary line that divides the liver into right and left lobes, running from the IVC to the Gall Bladder fossa.

Liver Segments

The liver is divided into right and left lobes, with the right lobe consisting of segments 5, 6, 7, and 8, and the left lobe consisting of segments 2, 3, and 4.
Each segment has its own blood supply and biliary drainage, and is functionally independent.
The caudate lobe (segment 1) drains directly into the inferior vena cava.

Liver Function and Tests

The liver has a synthetic function, producing approximately 10g of albumin per day, with a half-life of 15-20 days.
Albumin is a prognostic indicator, and the degree of decrease in albumin corresponds to the degree of liver damage.
The international normalized ratio (INR) is a measure of the ratio of prothrombin time to mean control prothrombin time.
Liver function tests (LFTs) are a misnomer, as they measure liver damage or injury rather than function.

Liver Pathology

Amebic liver abscesses often start with intestinal amebiasis, which may not present with diarrhea.
The absence of diarrhea does not rule out an amebic abscess.
The diagnosis of an amebic abscess is confirmed with a CT scan, which shows a non-enhancing and ragged-edge lesion.

Liver Imaging and Diagnosis

The triple-phase CT scan is the gold standard for liver imaging, with three phases: arterial, portal venous, and washout.
Each phase helps to differentiate between different types of tumors.
Hemangiomas are the most common benign liver tumors, and are characterized by peripheral nodular enhancement with progressive centripetal enhancement.
Focal nodular hyperplasia is a hyperplastic lesion of hepatocytes surrounding a congenital arteriovenous malformation, and is commonly found in females aged 20-50.### Simple Cyst
Best seen during the arterial phase
Can differentiate cystic contents using MRI
Can demonstrate even subtle nodulation along the wall
Central stellate scars are thought to be formed in response to oxidative stress caused by concomitant arterial hyperperfusion
Management for symptomatic simple cyst:
- Part of the cyst wall is resected to allow a permanent drainage
- High recurrence rate
- Aspiration: associated with severe recurrence, 20% recurrence rate
- Medical treatment: Octreotide & Lanreotide, Sirolimus
- Sclerotherapy: gives immediate relief of symptoms, 92% effective
- Fenestration: considered with massive hepatomegaly, 22% recurrence rate
- Hepatic resection: considered with numerous cysts, especially those with spared at least one segment
- OLT (Orthotopic Liver Transplant): considered in severe cases

Mucinous Cystic Neoplasm

Complex cyst with thickened walls/nodule
Septation described as "cyst in cyst" appearance
Contain bloody or chocolate-like fluid
With malignant potential over a prolonged period of time (10 years)

Adenoma

Beta-catenin activated adenoma: most common among men, associated with androgen use
Imaging:
- Hypovascular on the early arterial phase
- Homogenous uptake on the late arterial phase
- 30% have pseudo-capsule
MRI with contrast (gadoxectic or ferumoxide)
Technetium 99 sulfur colloid scan: treatment of choice for bleeding hepatic adenoma

Malignant Lesions

Hepatocellular Carcinoma (HCC): 5th most common malignancy
Major risk factors:
- Viral hepatitis (B or C)
- Alcoholic cirrhosis
- Hemochromatosis
- NASH
Clinical manifestations:
- Weight loss
- Hepatomegaly
- Tender abdominal mass
- Jaundice
- Caput medusae
- Ascites
Diagnostic tests:
- Alpha-fetoprotein (AFP) >400 mg/mL
- Liver Imaging Reporting & Data System (LIRADS)
Treatment:
- Liver resection
- Liver transplant
- Transarterial chemoembolization (TACE)
- Radiofrequency ablation
- Percutaneous ethanol injection

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Description

This quiz covers the anatomy of the liver, including its unique blood supply and function. Learn about the liver's structure and importance in the human body.