Abdominal Ultrasound Flashcards
Density on ultrasound
impedence
Targetoid lesion in the liver
Highly likely to be metastatic disease
Anechoic lesion in the liver
Likely a cyst
Homogeneously mildly hyperechoic, well-defined lesion on liver ultrasound
Likely to be a hemangioma
Posterior acoustic shadowing
Reverberation
Comet tail artifact
A type of reverberation artifact
Ring down artifact
Due to trapping by air
Pathognomonic for the presence of air
Twinkle artifact
Detects waveforms that vibrate within a structure - when that sturcture is very hard
“Motion” when there is none
Useful for detecting stones
Pancreas ultrasound
Can often see the splenic vein running longitudinally along the pancreas
The SMA runs behind the splenic vein.
Ultrasonographic pancreas anatomy
How do you find the common bile duct?
Find the portal vein. Follow it up. The CBD will run alongside as it approaches the liver.
Follow the CBD out to ensure you haven’t mistakenly found the cystic duct.
It will also be the only tubular structure that does not light up on doppler.
Serpiginous gallbladder
Totally normal variant
As long as the walls aren’t thickened and there are no stones, you’re good!
How can you tell if ‘stuff’ in the gallbladder is sludge?
Ask the patient to move!
Wall echo shadow sign
CBD diameter
6 mm if under age 50
After 50, + 1 mm for every decade of life
Hepatitis on ultrasound
“Starry sky” liver
The peri-vascular hyperemia is due to the infammatory exudate coming from the vasculature
When is ultrasound not first line for a pulsatile abdominal mass?
- Patient is actively symptomatic
- Patient is too obese for an US to visualize the mass
- In these cases, CT is preferred.
- Theoretically, MRI could be used, but is expensive and slow, making it suboptimal in any real world scenario.
Ddx for pulsatile abdominal mass
- AAA
- Tortuous aorta
- Nonvascular mass adjacent to the aorta
What is the minimum diameter of the abdominal aorta in a male vs female that is considered aneurysmal?
Both 3.0 cm, but recommendations for female tend to be 0.5 cm sooner than for male as AAAs are at higher risk of rupture in females.
Two groups for whom asymptomatic screening for AAA is indicated
- Males aged 65-75 who have ever smoked
- Males age > 60 who have a sibling or parent with hx of AAA
