GI Section V: Hepatioc Doppler Flashcards
‘‘Duplex” means
Color
“spectral” means
Color with Waveform
When an organ needs to be “on,” its arteriolar bed dilates, and the waveform becomes?
Low resitance
When an organ goes to “power save” mode, it directs the arterioles to?
Constrict
To help quantify this low resistance high resistance thing in Doppler, we use this
“Resitive Index (RI)”
RI is defined as?
V1-V2/V1
Just remember that things that need blood all the time, will have?
Just remember that things that need blood all the time, will have continuous diastolic flow - and thus a low resistance wave form.
What is this ‘‘Tardus” ?
Refers to a slowed systolic upstroke.
an be measured by:
Accelaration time, time from end diastole to teh first systole peak
An acceleration time > 0.07 sec correlates with
> 50% stenosis of renal artery
What is “Parvus”?
decreased systolic velocity. This can be measured by calculating the acceleration index, the change in velocity from end diastole to the first systolic peak.
An acceleration index <3.0 m/sec- correlates with
> 50% stenosis of renal artery
Blood that has NOT yet passed through the stenosis
Upstream
Blood that has passed through the area of stenosis
Downstream
Direct Signs of stenosis?
those found at the stenosis itself
Elevated Peak Systolic Velocity
Spectral Broadening (Immediate post stenotic)
Indirect signs of stenosis?
tardus parvus (downstream) - with time ot peak (systolic acceleration) > 70 msec
Low downstream RI < 0.5 (liver is tarved of blood)
High upstream RI > 0.6) blood needs to overcome the area of stenosis
Describe the flow of hepatic veins
Complex
Alternating foreward and backward flow
What should be the bulk of flow in the hepatic veins?
should be antegrade
Liver —> heart
What are the things that mess with the wavefrom?
Pressure changes in the RIGHT heart which are transitted to the hepatic veins (CHF/Tricuspid regurg) or compression of the veins directly (cirrhosis)
Anything that increases the right atrial pressure (Atrial contraction) will cause the wavef to?
Slope upward
“A” represents atrial contraction.
Anything that decreases right atrial pressure will cause the wave to?
Slope downward
Abnormal Hepatic Vein Waveforms can manifest in one of three main categories:
(1) More Pulsatile
(2) Less Pulsatile
(3) Absent = Budd Chiari
Increased HV Pulsatility
Tricuspid Regurg
Right Sided CHF
Decreased HV Pulsatility
Cirrhosis
Hepatic Venous Outflow Obstruction (any cause)
Tricuspid Regurg =
Right heart failure =
Tricuspid Regurg = D deeper than S
Right heart failure = S deeper than D
Flow in the portal vein should always be?
Towards the liver
Velocity in the normal portal vein
between 20-40 cm/s.
You have three main waveform patterns of portal vein
Causes of Portal Vein Pulsatility:
Right-sided CHF
Tricuspid Regurg
Cirrhosis with Vascular AP shunting
Causes of Portal Vein Reversed Flow
The big one is Portal HTN (any cause).
Absent Flow of the portal vein causes
It’s seen in thrombosis, tumor invasion,
and stagnant flow from terrible portal HTN.
most common cause of slow flow (Velocities < 15 cm/s)
Portal HTN
Causes of PV slow flow
- Pre - Portal Vein Thrombosis
- Intra - Cirrhosis (any cause)
- Post - Right-sided Heart Failure, Tricuspid Regurg, Budd-Chiari
“what should the Doppler angle be?”
Why?
The answer is “less than 60. ”
- the doppler strength follows the Cos.
