POCUS - Abdominal Flashcards

1
Q

According to a 2005 meta-analysis, what is the sensitivity and specificity of eFAST for hemoperitoneum?

A

Sens: 79%
Spec: 99.2%

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2
Q

Why is eFAST not perfectly sensitive for hemoperitoneum?

A

A couple of reasons:

  • Adhesions could cause trapping of blood in non-FAST views
  • There are anatomic gutters that blood can accumulate in that are not seen on FAST
  • Position of patient can cause false negatives
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3
Q

FAST will miss hemoperitoneum below what threshold of bleeding?

A

Thought to be 250 mL

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4
Q

It’s important to note that FAST will miss what type of abdominal trauma?

A

Solid-organ injury without hemoperitoneum

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5
Q

Describe the usual path of bleeding in the peritoneum.

A
  • Bleeding from the spleen typically collects in the sub-phrenic space. Overflow will go down along the transverse colon to the liver (because of the ligament at the splenic flexure).
  • Bleeding from the liver will collect in Morrison’s pouch and usually go down the ascending colon to the pelvis.
  • Bleeding from the pelvis will typically stay in the pelvis. If there is overflow it will go first to the liver.
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6
Q

True or false: blood on FAST will always be anechoic.

A

False

It can be mildly echogenic.

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7
Q

About _____% of patients with cholecystitis have stones in the CBD.

A

15

Because of this, the decision to operate in cholecystitis should only be done after the CBD is assessed.

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8
Q

The gallbladder is normally ___ cm long.

A

7

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9
Q

The common bile duct is made by the fusion of the cystic duct with the _______________ duct.

A

common hepatic

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10
Q

To begin the sagittal view of the gallbladder, place the probe ______________.

A

in the mid-clavicular line, just below the costal margin, with the probe indicator pointed to the patient’s R shoulder

From there, you may need to fan and slide to find the gallbladder.

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11
Q

The gallbladder lies _________ and _________ to the R kidney.

A

anterior; medial

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12
Q

The _____________ is a landmark that connects the portal vein to the gallbladder. It can be used to help identify the gallbladder.

A

main lobar fissure

It is typically seen in the sagittal (longitudinal) view of the gallbladder.

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13
Q

The ideal patient position for finding the gallbladder is ____________.

A

supine (deep inspiration can help) and tilted slightly to the left

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14
Q

If you see stones in the gallbladder neck, you must _________________.

A

repeat the views with the patient in a different position (so that you can see if it is stuck)

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15
Q

There are three things to consider when you can’t find the gallbladder. What are they?

A
  • Surgical absence (look for surgical clips)
  • Contracted to the point of not being recognizable
  • Full of stones (and thus looking like bowel artifact)
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16
Q

True or false: the transverse gallbladder view should be taken from the R side.

A

False

It can be done that way if that is the only obtainable view, but it is preferably done from the anterior aspect.

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17
Q

The hepatorenal space has what eponym?

A

Morrison’s pouch

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18
Q

The haustra on small bowel are called ___________.

A

plicae circularis

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19
Q

In pediatric patients, list the most frequent places blood will collect.

A

1) RUQ
2) Pelvis
3) Dome of the spleen

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20
Q

The most sensitive area for detection of free fluid in the abdomen is _______________.

A

the caudal tip of the liver

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21
Q

What are the sensitivity and specificity of the FAST exam for intraabdominal bleeding?

A
  • Sensitivity: 66%

- Specificity: 95%

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22
Q

What’s the minimum amount of fluid needed for a FAST to be positive?

A

200 mL

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23
Q

Where does fluid first collect in the LUQ?

A

Between the spleen and diaphragm

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24
Q

What studies should you obtain in the gallbladder US?

A
  • Long axis showing neck
  • Short axis
  • Anterior wall thickness
  • CBD (w/ color if uncertain)
  • Gallbladder length
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25
Q

The CBD is right on top of the _______________.

A

portal vein

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26
Q

True or false: the CBD has hyperechoic borders and appears bright white on both sides.

A

False

The portal vein appears this way.

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27
Q

Always look in the ___________ in the gallbladder US.

A

neck

Be sure to look for shadowing that may indicate a stone.

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28
Q

The portal vein is ___________ to the hepatic artery and CBD.

A

deep/posterior

This is why the CBD is “on top” of the portal vein from the transverse view.

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29
Q

The CBD is usually ____________ to the hepatic artery.

A

lateral

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30
Q

How many lung views do you need in an eFAST?

A

6 total (3 each side)

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31
Q

Where do you put the probe in the perihepatic view of the FAST exam?

A

Mid axillary line in the 8th-11th intercostal spaces with the probe marker pointed to the patient’s head

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32
Q

__________ capsule surrounds the liver.

A

Glisson’s

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33
Q

When doing a search for bleeding (such as the FAST) beware of ___________ that will not appear anechoic.

A

clotted blood

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34
Q

It’s rare to develop pyloric stenosis after what age?

A

12 weeks

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35
Q

True or false: use the curvilinear probe to identify pyloric stenosis.

A

False

Use the linear

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36
Q

US is actually more sensitive than ____________ in detecting pneumoperitoneum.

A

plain radiographs

One study showed that US can detect as little as 1 mL of air.

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37
Q

What locations (and patient positions!) are best for detecting free air in the abdomen?

A
  • RUQ, curvilinear probe, patient in left-lateral decubitus position looking for air above the dome of the liver: 83%
  • Epigastric area, curvilinear probe, patient supine: 81%
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38
Q

What should you look for in detecting pneumoperitoneum?

A

A lines that do not vary with respiration with distortion behind the A lines (that is, distortion where there should not be distortion such as over the liver)

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39
Q

What might appear like pneumoperitoneum over the RUQ?

A

Subcutaneous air from a PTX

Look for the peritoneal stripe. If the air signal arises from above that then it is no intraperitoneal.

40
Q

What is Chalaiditi’s anomaly?

A

Bowel that is interposed between the liver and the diaphragm

This is important in US because it can look like pneumoperitoneum over the RUQ.

41
Q

You can see ________________ in those with ascites who develop pneumoperitoneum.

A

bubbles in the ascites

42
Q

How does ring down artifact differ in appearance from comet tail artifact?

A

Both appear as bright columns, but comet tail decreases in intensity the farther it gets from the probe, whereas ring down stays as a uniformly bright band.

43
Q

How does emphysematous cholecystitis appear on US?

A

A bright white, irregular wall with ring down artifact

44
Q

How does pneumobilia present?

A

Look for bright white streaks in the liver. These are bubbles that deflect US waves.

45
Q

What things can cause portal venous gas?

A
NEC
Umbilical vein catheterization in neonates
Ischemic bowel 
Perforated ulcer
Invasive colorectal cancer 
Intrasbdominal infection (appendicitis, cholecystitis, diverticulitis) 
Barotrauma 
Steroid use 
Post op
46
Q

Compared to pneumobilia, portal venous gas will appear _____________.

A

more peripherally and generally smaller (like a more speckly appearance rather than large bubbles)

Otherwise, both pneumobilia and portal venous gas look like bright white bubbles in the liver with posterior ring downing.

47
Q

What can appear like pneumobilia or portal venous gas?

A

Hepatic calcifications

48
Q

What is the normal length and width of a gallbladder?

A

Width less than 4 cm

Length less than 8 cm (Dr. Jones says 10 cm)

49
Q

What is the age-adjusted CBD diameter?

A

6 mm plus 1 mm for each decade of life after 60

50
Q

True or false: the dot of the exclamation mark is the CBD.

A

False

The dot is the portal vein. The CBD will be on top of the dot.

51
Q

When you find the Mickey Mouse sign of the hepatic triad, the hepatic artery is usually Mickey’s _________ ear.

A

L (right on the screen)

52
Q

If you see a stone in the gallbladder neck, be sure to have _______________.

A

the patient move to R-lateral decubitus and see if the stone is mobile

53
Q

What is the WES sign?

A

Wall echo shadow

This is when the gallbladder is so full of stones that it appears as an irregular hyperechoic line with a shadow behind it.

54
Q

What are the signs of appendicitis?

A
  • Dilated (outer wall to outer wall greater than 6 mm)
  • Fluid surrounding the appendix
  • Appendicolith
  • Hyperemia on color flow
  • Hyperechoic fat surrounding it
55
Q

When scanning for the appendix, start ____________.

A

where it hurts

56
Q

The appendix is normally anterior to the _____________.

A

R psoas muscle

57
Q

What do you need to scan for an SBO study?

A
  • Bowel loop diameter (greater than 2.5 cm is abnormal)
  • Bowel wall thickness (greater than 4 mm)
  • Clip showing no peristalsis or to-and-fro peristalsis
58
Q

What is the Tanga sign?

A

The Tanga sign comes from a type of underwear. It shows up in a patient with severe SBO as a bikini-shaped anechoic area next to obstructed bowel.

59
Q

What do you need for an intussusception study?

A

Two scans per quadrant (one up and down, one side to side)

60
Q

True or false: the perihepatic window done in the eFAST exam is ideally supposed to be subcostal.

A

False

It should be intercostal and done between the 8th and 11th ribs.

61
Q

What is one way to tell if an anechoic area in Morrison’s pouch is gallbladder (as opposed to blood)?

A

Gallbladders have a hyperechoic border while blood does not.

62
Q

What hyperechoic structure may be in the hepatorenal space?

A

Perinephric fat

63
Q

Bleeding seen on US in the hepatorenal space will usually be between what two tissue planes?

A

Glissson’s capsule (around the liver) and Gerota’s fascia (tissue around the perinephric fat)

Bleeding beneath Gerota’s fascia is a sign of retroperitoneal bleed.

64
Q

How will liver hematoma appear?

A

As a hyperechoic area within the liver

65
Q

Review the technical landmarks for the perisplenic window.

A

L posterior axillary line between the 8th and 11th ribs in a coronal view tilted slightly obliquely

66
Q

Because the spleen is so much smaller than the liver, you need to angle your probe _____________ to obtain the splenorenal fossa.

A

posteriorly (toward the spine)

67
Q

If you angle too anteriorly in the splenic window, you will see the ______________.

A

stomach (this can look like hemothorax or blood in the splenorenal fossa)

68
Q

Subcapsular hematomas of the spleen appear ___________.

A

as hypo- or hyperechoic collections contained within a capsule on the spleen

69
Q

What might appear like a perisplenic fluid collection but is not?

A

Liver

If someone has hepatomegaly, their liver may touch the spleen and appear like a subcapsular hematoma. You can use color flow to determine if it is the liver (which will have pulsating vessels) or a hematoma (which will not).

70
Q

The spleen and liver should always appear ____________.

A

homogeneous

If you notice areas that appear hyperechoic then you should be concerned for parenchymal injury.

71
Q

In a male patient, pelvic bleeding usually shows up ___________ to the prostate and seminal vesicles.

A

superior

72
Q

If you don’t know if an anechoic structure is free fluid or a contained cavity like the bladder, lumen of bowel, or a cyst, then check for what features at the borders?

A
  • A luminal wall

- The shape of the fluid: rounded edges are likely a lumen; triangular edges are likely free fluid

73
Q

A gallbladder tip that is folded onto itself is called a ____________.

A

Phrygian cap

74
Q

How can you tell the difference between a septation and a Phrygian cap?

A

Phrygian cap will cause change in the outer contour of the GB wall.

75
Q

A gallbladder fold near the neck is called what?

A

A junctional fold

76
Q

Gallbladder sludge is isoechoic to what?

A

The liver

77
Q

What features of a gallbladder polyp make it high risk for malignancy?

A

Size greater than 6 mm in a person older than 50 years

78
Q

Diffuse gallbladder wall thickening can be due to what non-biliary causes?

A
  • Cirrhosis
  • Edema
  • Adenomyomatosis (think this if irregularity is present)
79
Q

The CBD should be measured how?

A

Inner wall to inner wall

80
Q

In what patients is a CBD of 1 cm normal?

A

Post-cholecystectomy

81
Q

What percent of people with symptomatic cholelithiasis or cholecystitis have CBD stones?

A

18%

82
Q

Review Jacob Avila’s approach to GB.

A

He uses the intercostal view. Hee advises starting at the level of the xiphoid and then fanning transverse 7 cm.

If this doesn’t work, then try the subcostal or transhepatic windows. Held inspiration and LLD positioning can help.

83
Q

The appendix is usually bound by what borders?

A

Lateral: iliac crest
Medial: internal iliac artery
Posterior: psoas muscle

84
Q

Much of the time, the appendix is directly anterior to ___________.

A

the iliac artery

85
Q

The major criteria for diagnosing appendicitis are ____________.

A

non-compressible and > 6 mm (3 + 3 is normal)

86
Q

True or false: the cutoff for SBO intestine width is 3 cm.

A

False

2.5 cm

87
Q

Free fluid around an SBO is the ___________ sign.

A

Tanga

88
Q

The most high-yield area for SBO scanning is the ______________.

A

lateral lower quadrants (dependent areas where fluid is likely to be)

89
Q

Describe the EPSS of the bowel.

A

It essentially looks like the A lines of the lungs. Normally, the peritoneal stripe should be vague and irregular. If it looks like a clean, linear, bright white stripe then it is concerning for pneumoperitoneum.

90
Q

Robert Jones advises that you use the ____________ technique for scanning for SBO.

A

lawnmover (scanning up and down across the whole abdomen)

91
Q

Review the five signs of SBO.

A

Dilated small intestine (> 2.5 mm)
Peritoneal free fluid (Tanga sign)
Decreased peristalsis or to-and-fro peristalsis
Bowel wall edema (>4 mm)
Transition point

92
Q

True or false: US has nearly 100% sensitivity and specificity for intussusception.

A

True

93
Q

Intussusception has what two signs?

A

Pseudokidney (long axis)
Target sign (short axis)

94
Q

What ultrasound finding is a contraindication to air enema?

A

Large volume free fluid in the peritoneum (concerning for perforation)

95
Q

How does inflammatory fat appear on US?

A

Hyperechoic (sometimes seen around the appendix)

96
Q

Where does portal gas accumulate? Where does biliary gas occur?

A

Portal = Peripheral
Bile = central