POCUS - Abdominal

Question 1

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

Answer 1

Sens: 79%
Spec: 99.2%

Question 2

Why is eFAST not perfectly sensitive for hemoperitoneum?

Answer 2

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

Question 3

FAST will miss hemoperitoneum below what threshold of bleeding?

Answer 3

Thought to be 250 mL

Question 4

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

Answer 4

Solid-organ injury without hemoperitoneum

Question 5

Describe the usual path of bleeding in the peritoneum.

Answer 5

• 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.

Question 6

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

Answer 6

False

It can be mildly echogenic.

Question 7

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

Answer 7

15

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

Question 8

The gallbladder is normally ___ cm long.

Answer 8

7

Question 9

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

Answer 9

common hepatic

Question 10

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

Answer 10

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.

Question 11

The gallbladder lies _________ and _________ to the R kidney.

Answer 11

anterior; medial

Question 12

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

Answer 12

main lobar fissure

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

Question 13

The ideal patient position for finding the gallbladder is ____________.

Answer 13

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

Question 14

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

Answer 14

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

Question 15

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

Answer 15

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

Question 16

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

Answer 16

False

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

Question 17

The hepatorenal space has what eponym?

Answer 17

Morrison’s pouch

Question 18

The haustra on small bowel are called ___________.

Answer 18

plicae circularis

Question 19

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

Answer 19

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

Question 20

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

Answer 20

the caudal tip of the liver

Question 21

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

Answer 21

• Sensitivity: 66%

- Specificity: 95%

Question 22

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

Answer 22

200 mL

Question 23

Where does fluid first collect in the LUQ?

Answer 23

Between the spleen and diaphragm

Question 24

What studies should you obtain in the gallbladder US?

Answer 24

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

Question 25

The CBD is right on top of the _______________.

Answer 25

portal vein

Question 26

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

Answer 26

False The portal vein appears this way.

Question 27

Always look in the ___________ in the gallbladder US.

Answer 27

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

Question 28

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

Answer 28

deep/posterior This is why the CBD is "on top" of the portal vein from the transverse view.

Question 29

The CBD is usually ____________ to the hepatic artery.

Answer 29

lateral

Question 30

How many lung views do you need in an eFAST?

Answer 30

6 total (3 each side)

Question 31

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

Answer 31

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

Question 32

__________ capsule surrounds the liver.

Answer 32

Glisson's

Question 33

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

Answer 33

clotted blood

Question 34

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

Answer 34

12 weeks

Question 35

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

Answer 35

False Use the linear

Question 36

US is actually more sensitive than ____________ in detecting pneumoperitoneum.

Answer 36

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

Question 37

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

Answer 37

- 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%

Question 38

What should you look for in detecting pneumoperitoneum?

Answer 38

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)

Question 39

What might appear like pneumoperitoneum over the RUQ?

Answer 39

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

Question 40

What is Chalaiditi's anomaly?

Answer 40

Bowel that is interposed between the liver and the diaphragm This is important in US because it can look like pneumoperitoneum over the RUQ.

Question 41

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

Answer 41

bubbles in the ascites

Question 42

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

Answer 42

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.

Question 43

How does emphysematous cholecystitis appear on US?

Answer 43

A bright white, irregular wall with ring down artifact

Question 44

How does pneumobilia present?

Answer 44

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

Question 45

What things can cause portal venous gas?

Answer 45

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

Question 46

Compared to pneumobilia, portal venous gas will appear _____________.

Answer 46

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.

Question 47

What can appear like pneumobilia or portal venous gas?

Answer 47

Hepatic calcifications

Question 48

What is the normal length and width of a gallbladder?

Answer 48

Width less than 4 cm Length less than 8 cm (Dr. Jones says 10 cm)

Question 49

What is the age-adjusted CBD diameter?

Answer 49

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

Question 50

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

Answer 50

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

Question 51

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

Answer 51

L (right on the screen)

Question 52

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

Answer 52

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

Question 53

What is the WES sign?

Answer 53

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.

Question 54

What are the signs of appendicitis?

Answer 54

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

Question 55

When scanning for the appendix, start ____________.

Answer 55

where it hurts

Question 56

The appendix is normally anterior to the _____________.

Answer 56

R psoas muscle

Question 57

What do you need to scan for an SBO study?

Answer 57

- 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

Question 58

What is the Tanga sign?

Answer 58

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.

Question 59

What do you need for an intussusception study?

Answer 59

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

Question 60

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

Answer 60

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

Question 61

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

Answer 61

Gallbladders have a hyperechoic border while blood does not.

Question 62

What hyperechoic structure may be in the hepatorenal space?

Answer 62

Perinephric fat

Question 63

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

Answer 63

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.

Question 64

How will liver hematoma appear?

Answer 64

As a hyperechoic area within the liver

Question 65

Review the technical landmarks for the perisplenic window.

Answer 65

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

Question 66

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

Answer 66

posteriorly (toward the spine)

Question 67

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

Answer 67

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

Question 68

Subcapsular hematomas of the spleen appear ___________.

Answer 68

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

Question 69

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

Answer 69

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).

Question 70

The spleen and liver should always appear ____________.

Answer 70

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

Question 71

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

Answer 71

superior

Question 72

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?

Answer 72

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

Question 73

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

Answer 73

Phrygian cap

Question 74

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

Answer 74

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

Question 75

A gallbladder fold near the neck is called what?

Answer 75

A junctional fold

Question 76

Gallbladder sludge is isoechoic to what?

Answer 76

The liver

Question 77

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

Answer 77

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

Question 78

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

Answer 78

- Cirrhosis - Edema - Adenomyomatosis (think this if irregularity is present)

Question 79

The CBD should be measured how?

Answer 79

Inner wall to inner wall

Question 80

In what patients is a CBD of 1 cm normal?

Answer 80

Post-cholecystectomy

Question 81

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

Answer 81

18%

Question 82

Review Jacob Avila's approach to GB.

Answer 82

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.

Question 83

The appendix is usually bound by what borders?

Answer 83

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

Question 84

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

Answer 84

the iliac artery

Question 85

The major criteria for diagnosing appendicitis are ____________.

Answer 85

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

Question 86

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

Answer 86

False 2.5 cm

Question 87

Free fluid around an SBO is the ___________ sign.

Answer 87

Tanga

Question 88

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

Answer 88

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

Question 89

Describe the EPSS of the bowel.

Answer 89

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.

Question 90

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

Answer 90

lawnmover (scanning up and down across the whole abdomen)

Question 91

Review the five signs of SBO.

Answer 91

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

Question 92

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

Answer 92

True

Question 93

Intussusception has what two signs?

Answer 93

Pseudokidney (long axis) Target sign (short axis)

Question 94

What ultrasound finding is a contraindication to air enema?

Answer 94

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

Question 95

How does inflammatory fat appear on US?

Answer 95

Hyperechoic (sometimes seen around the appendix)

Question 96

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

Answer 96

Portal = Peripheral Bile = central