GI Section III: Diffuse Liver Processes

Question 1

How to Call Fatty Liver on CT?

Answer 1

1. < 40 HU on NECT
2. < 100 HU on PVP
3. < 25 HU less than the spleen

Question 2

How to Call Fatty Liver on US?

Answer 2

Brighter than the kidney

Question 3

How to Call Fatty Liver on MRI?

Answer 3

Two standard deviation difference between in and out of phase imagin

Out-of-phase SIGNAL DROP

Question 4

What does signal drop out assume on MRI?

Answer 4

there is more water than fat in the liver

the degree of signal loss is maximum when the fat infiltration is 50% (exactly 1:1 signal loss)

When the percentage of fat grows larger than 50% you will actually see a less significant signal loss on out of phase imaging, relative to that maximum 50%.

Question 5

What causes signal drop?

Answer 5

McDonalds, Burger King, and Taco Bell.

Additional causes include:
chemotherapv (breast cancer)
steroids
cystic fibrosis.

Question 6

Iron overload

Answer 6

Hemochromatosis

Question 7

You can show hemochromatosis is three main ways:

Answer 7

1. The liver and spleen being T1 and T2 dark.
2. T2 only: absent spleen (chronic hemolytic anemia = multiple blood transfusions = hemochromatosis = splenectomy), liver is darker (low signal) than muscle)
   * On T2 a normal liver should always have a signal higher than muscle
3. Low signal on in phase, and high signal on out of phase. (“Iron on In-phase”)

Question 8

FAT vs IRON in IP - OOP MRI

Answer 8

FAT - Signal Drop on OOP

IRON - Signal drop in IP

Question 9

Answer 9

A. Hereditary hemochromatosis - Low signal Liver / Normal spleen

B. Prolonged treatment with phlebotomies: Normal Signal liver

C. Secondary hemochromatosis: Low signal on Liver and spleen

Question 10

Hemocrhomatosis

Liver + Pancreas

Answer 10

Primary hemochromatosis

Question 11

Hemochromatosis

Liver + spleen

Answer 11

Secondary hemochromatosis

Question 12

Hemochromatosis

Genetic - increased absorption

Answer 12

Primary hemochromatosis

Question 13

Hemochromatosis

Acquired - chronic illness, and multiple transfusions

Answer 13

Secondary hemochromatosis

Question 14

How does the body react in secondary hemochromatosis?

Answer 14

result of either chronic inflammation or multiple transfusions.

body reacts by trying the “Eat the Iron,” with the reticuloendothelial system

Question 15

Hypercoaguable patient (pregnant or idiopathic - mc example) = Hepatic vein thrombosis

Answer 15

Budd Chiary Syndrome

Question 16

Budd-Chiary syndrome

Answer 16

1. Obstruction - hepatic venous outflow
2. Intrahepatic and systemic collateral veins
3. Large regenerative (hyperplastic) nodules in a dysmorphic liver
4. LArge caudate lobe (massive) - spared from separate drainage into IVC)

Question 17

Early and delayed phases of liver enhancement

Answer 17

Budd-Chiari Syndrome

“flip-flop pattern

AP: Central enhancement Peripheral minumal
PVP: Central washout (Low attenuation) and high peripherally

Question 18

Who gets a “Nutmeg Liver”

Answer 18

• Budd Chiari
• Hepatic Veno-occlusive disease
• Right Heart Failure (Hepatic Congestion)
• Constrictive Pericarditis

Question 19

“nutmeg” with an inhomogeneous mottled appearance, and delayed enhancement of the periphery of the liver.

Answer 19

Budd-Chiari Syndrome

Question 20

Answer 20

Regenerative (hyperplasic) nodules in Budd Chiari

High T1 low/iso T2

Question 21

Budd-Chiarri vs HCC nodules

Answer 21

Big (>10cm) and small (<4cm) nodules in Budd chiarri = benign

Budd Chiari = T2 Dark
HCC = T2 bright

Question 22

Acute vs Chronic Budd-Chiari syndrome

Answer 22

Acute = rapid onset ascites

Chronic = fibrosis of the intrahepati veins due to infplammateion

Question 23

Who gets massive caudate lobe hypertrophy?

Answer 23

Budd-Chiari
Primary Sclerosing Cholangitis
Primary Biliary Cirrhosis

Question 24

Budd Chiari that occurs from occlusion of the small hepatic venules (Instead of hepatic venous outflow)

Answer 24

Hepatic Veno-occlusive Disease

Question 25

Hepatic Veno-occlusive Disease waveforms

Answer 25

Nomal Hepatic veins
Normal IVC
Abnormal Portal waveforms (Slow, reversed, to-and-fro)

Question 26

Passive hepatic congestion is caused by

Answer 26

stasis of blood within the liver due to compromise of hepatic drainage

Question 27

common complication of congesfive heart
failure and constrictive pericarditis

Answer 27

Passive congestion

Question 28

Result of elevated CVP transmitted from the right atrium to the hepatic veins

Answer 28

Passive congestion

Question 29

Passive congestion findings:

Answer 29

Refluxed contrast into the hepatic veins
Increased portal venous pulsatility
Nutmeg liver