Hepatoportal System Flashcards
What percentage of blood is supplied to the liver via the portal vein?
75% - nutrient rich blood from GI tract
What is the TRV fissure on the visceral surface of the liver between the caudate and quadrate lobes?
Porta hepatis
Do the portal veins course between or within the liver?
WITHIN - “intrasegmental”
What landmark identifies the start of the PHA from the CHA?
GDA
What patient position offers EXCELLENT visualization of porta hepatis?
Rt coronal oblique
Where should the PV be measured?
Where it crosses the IVC - inner to inner wall
What is the normal PV diameter?
Less than or equal to 13mm
What does an increase in caliber of less than 20% in the splenic vein during deep inspiration indicate?
Portal hypertension
Which of the following increases blood flow within the portal, splenic, and superior mesenteric veins?
a. inspiration and ingestion of food
b. inspiration and exercise
c. expiration and exercise
d. expiration and ingestion of food
D
What is a normal resistive index in the hepatic artery?
a. 0.2 to 0.4
b. 0.8 to 1.0
c. 0.5 to 0.7
d. 1.3 to 1.5
C
What is the most common etiology for portal hypertension in North America?
a. portal vein thrombosis
b. Budd–Chiari syndrome
c. hepatitis C infection
d. cirrhosis
D
What is the primary complication of portal hypertension?
a. portal vein thrombosis
b. gastrointestinal bleeding
c. hepatic vein thrombosis
d. splenomegaly
B
Which of the following is NOT a duplex sonographic finding associated with portal hypertension?
a. increased portal vein diameter
b. decreased or absent respiratory variation in portal and splenic veins
c. hepatopetal flow in the portal and splenic veins
d. portosystemic collaterals (varices)
C - it would be hepatoFUGAL flow
What is the most common portosystemic collateral shunt in the presence of portal hypertension?
a. recanalized paraumbilical vein
b. splenorenal veins
c. gallbladder varices
d. coronary–gastroesophageal veins
D
Which of the following is a treatment of portal hypertension that involves jugular vein cannulation with stent placement in the liver?
a. mesocaval shunt
b. splenorenal shunt
c. TIPS
d. PVTS
C
Which of the following is NOT a normal finding in a transjugular portosystemic shunt?
a. hepatofugal flow in the main portal vein
b. velocities within the stent in the range of 90 to 190 cm/s
c. hepatofugal flow in intrahepatic portal veins beyond the site of stent connection
d. increased flow velocities in the splenic vein
A
Besides inferior vena cava dilatation, what distinct finding helps differentiate between congestive heart failure and portal hypertension?
a. increased pulsatility in the portal veins only
b. increased pulsatility in the hepatic veins only
c. increased pulsatility in both the portal and hepatic veins
d. decreased pulsatility in the hepatic veins only
C
Which of the following is NOT a sonographic finding in Budd–Chiari syndrome?
a. dilatation of the IVC with intraluminal echoes
b. pulsatile, phasic flow in non-occluded portions of the hepatic veins
c. enlarged caudate lobe
d. ascites and hepatomegaly
B
With the ingestion of food, what happens to the flow velocities within the PV and HA?
PV - flow increases
HA - flow decreases
The most specific finding of portal hypertension is the detection of?
Portosystemic collaterals
If portal vein thrombosis persists without lysis, development of periportal collateral veins increases and is known as?
Cavernous transformation
Portal hypertension is defined as “elevated pressure gradient between the portal vein and IVC or hepatic veins of” what pressure?
10-12 mmHg +
TIPS is a connection within the liver between what vessels?
Portal vein and hepatic vein
What is the hepatic blood outflow pathway?
PV –> sinusoids –> central vein –> interlobular veins –> hepatic veins –> IVC
MPV begins at the junction of?
Splenic vein and SMV
What hepatic vein is the largest?
RHV
The common hepatic artery branches off what vessel?
Celiac trunk
What is the normal velocity for resting PV flow?
16-31 cm/s
When would PV flow decrease?
During inspiration and when exercising
When would PV flow increase?
During expiration (decreasing abdominal pressure) and when eating (increased flow since PV is involved with the GI tract)
What is the normal diameter of the splenic vein?
10 mm with quiet respiration
What is the “hepatic arterial buffer response”?
When PV perfusion is decreased, the hepatic artery velocity will increase - this maintains liver perfusion in cases of cirrhosis and PVT
What happens to both the velocity AND pulsatility of the HA with the ingestion of food?
Velocity - decrease because the PV flow increases
Pulsatility - INCREASE
In portal hypertension, there is an increase in pressure gradient b/w what two veins?
PV and HV’s (10-12mm Hg)
What is the most common cause of portal hypertension?
Sinusoidal obstruction due to cirrhosis (caused by Hep C or alcohol abuse)
In cirrhosis, distorted liver parenchyma alters hepatoportal vascular channels. What is the outcome for PV’s and HV’s?
PV - increases resistance
HV - obstructs outflow
What are SF of portal hypertension?
- Increased PV diameter
- Enlarged caudate lobe
- Splenomegaly
- Cirrhosis - ascites and nodularity of liver capsule
- Portosystemic collateral veins (varices)
What happens to flow velocity with severe portal hypertension?
Velocity decreases - increased resistance to flow
What is the MOST specific finding of portal hypertension?
Portosystemic collateral veins (varices)
1. gastroesophageal varices
2. splenorenal varices
3. paraumbilical and abdominal wall varices
What is the most prevalent collateral in portal hypertension?
Gastroesophageal - found at GEJ which is POSTERIOR to the LT lobe of the liver - caused by reversed flow in L gastric/coronary vein
Describe splenorenal varices due to portal hypertension?
Large, tortuous vessels seen in the hilar region of the spleen and left kidney
Recanilized umbilical vein in portal hypertension arises from which portal vein and is located in which liver fissure?
- LPV
- Ligamentum Teres
What is diagnostic for portal hypertension relating to recanilized umbilical vein in terms of it’s diameter AND flow direction?
Diameter = > 3mm
Flow = hepatofugal
The umbilical vein drains into the systemic system via what vein?
Inferior epigastric vein
What is arterialization?
When the PV is obstructed, decreases the flow and in return, the HA will increase flow velocity to compensate and maintain liver blood perfusion
HA appears as a “corkscrew” color doppler appearance
What pathology is known as an “abnormal connection b/w artery & vein, where arterial blood flows into vein, bypassing capillaries” ?
AVF
What are the 3 types of hepatic AVF?
- Arterioportal (hepatic artery to portal vein)
- PV: pulsatile, hepatofugal flow
- HA: turbulent, increased end diastolic flow
- In connection: turbulent, high-velocity flow “color bruit”
- Portosystemic venous (portal vein to hepatic vein or IVC)
- Arteriosystemic (hepatic artery to hepatic vein)
What pathology results from flow stasis secondary to cirrhosis and portal hypertension, or extrinsic compression from malignancy?
PVT
Patients with what types of cancer are at increased risk of developing PVT due to direct invasion? (2)
- HCC
- Pancreatic cancer
SF of PVT?
- Absence of flow by spectral, color, or power Doppler in PV
- Increased PV diameter (>13 mm)
- Intraluminal echoes with variable echogenicity
- Increased hepatic arterial flow (arterialization)
Cavernous transformation occurs when what pathology is untreated?
PVT - multiple serpiginous vessels are seen in and around the occluded PV
What is cardiac cirrhosis also known as?
Congestive hepatopathy
What is cardiac cirrhosis caused by?
RSHF
What are the SF of the liver with cardiac cirrhosis?
- Hepatomegaly
- Portal - hepatic and IVC dilation
- Pulsatile flow in PV
- HV waveform demonstrates highly pulsatile inverted “W”- type pattern
What pathology is known as the “obstruction of the hepatic venous outflow tract due to hypercoagulable states”?
Budd-Chiari Syndrome
Patient presents with abdominal pain, jaundice, and elevated LFT’s. Upon scanning, you notice and enlarged caudate lobe and enlarged caudate vein along with hepatomegaly and splenomegaly. What is the most likely diagnosis?
Budd-Chirari
When does sinusoidal obstruction syndrome (SOS) typically occur?
After hematopoietic stem cell transplantation
Patient presents with a sudden onset of hepatomegaly, abdominal pain and jaundice. Upon scanning you notice that the PV’s and HV’s are patent. What is the most likely diagnosis?
SOS
What does TIPS stand for?
Transjugular Intrahepatic Portosystemic Shunt
What two vessels does TIPS connect?
RPV to RHV - blood shunted from portal vein directly to hepatic vein and then to IVC
What direction of flow is seen in the PV and HV with TIPS?
PV - hepatopetal flow
HV - hepatofugal flow
Shear wave elastography is a useful tool in evaluating what 3 things?
- Liver fibrosis in various liver diseases
- Portal hypertension
- Predicting the development of HCC
Elastography reduces the demand for what procedure?
Core liver biopsies