EDE

Question 1

How much fluid is normally in the pericardium?

Answer 1

50cc

Question 2

How much fluid is needed to see a pericardial effusion posteriorly in systole?

Answer 2

~100 cc

Question 3

How much fluid is needed to see a pericardial effusion posteriorly throughout the cardiac cycle?

Answer 3

100-300cc

Question 4

How much fluid is needed to see a pericardial effusion anteriorly and posteriorly?

Answer 4

> 300cc

Question 5

How much fluid can the pericardium accommodate (acutely) before there is hemodynamic compromise?

Answer 5

100-200 mL

If it accumulates slowly thats when you can see 300+ mL

Question 6

Name causes of false positives on Cardiac EDE?

Answer 6

1. Epicardial fat

Question 7

How do you distinguish epicardial tissue from an effusion?

Answer 7

It appears anteriorly first and dissapears posteriorly where an effusion would collect posteriorly first.

Question 8

In Aorta scan how can you distinguish aorta from IVC?

Answer 8

1. Wall thickness
2. Compressibility
3. Variation with resp (IVC will vary)
4. Sniff test (IVC will change) or can bear down

Question 9

What is one scenerio where the sniff test will be falsely negative?

Answer 9

If there are high right sided pressures like having a tamponade

Question 10

How big does the aorta have to be to not have a AAA?

Answer 10

<3cm

Question 11

Why isnt EDE able to detect a AAA rupture?

Answer 11

It does not visualize the retroperitoneum so will not see any free fluid.

Question 12

In respect to AAA’s what is the 95% rule? (that I made up)

Answer 12

95% are fusiform (saccular are less common), 95% are infrarenal, 95% rupture over 5cm and 95% rupture into the retroperitoneum.

Question 13

What is Morisons pouch

Answer 13

The hepatorenal space

Question 14

Why is the RUQ the best view?

Answer 14

• It is the 2nd lowest area in a supine pt (pelvis being the first) and the pelvis can only hold a small amount of fluid so any clinically significant bleed will track down into the RLQ via the right paracolic gutter.
• Bleeding in the LUQ will track to the RUQ by the phrenicolic ligament and mesentery of the transverse colon (without passing through the pelvis)

Question 15

The hepatorenal view alone will detect ___% of clinically significant cases

Answer 15

80%

Question 16

How much fluid is needed for EDE to detect it in the abdomen?

Answer 16

Most studies state 500mL, some states 900mL

Question 17

What are causes of false positives on the LUQ scan? (5)

Answer 17

1. Perinephric fat (often bilat and symmetrical and more echogenic)
2. Ascities
3. Peritoneal dialysis fluid (CAPD fluid)
4. Ovarian cyst rupture
5. Urine from rupture bladder

Question 18

What are 3 sources of false negatives on the Abdominal scan?

Answer 18

1. Adhesions - can cause loculations of fluid to accumulate. If pt has abdomen scars dont trust EDE
2. Delayed presentations (12-24 h after bleed, blood can clot and look more echogenic)
3. LUQ variability
   - blood doesnt only accumulate in splenorenal interface but also medial and superiorly

Question 19

What are the pelvis scans visualizing?

Answer 19

In men the rectovesicular pouch and in women the rectouterine pouch (pouch of douglas)

Question 20

What are causes of false + in pelvis scan in women?

Answer 20

Normally can have physiological fluid

Question 21

Pelvic scan: why in men is fluid only see anteriorly?

Answer 21

The rectum is retroperitoneal in men so will only see ‘mickey mouse ears’ inferior + lateral to the bladder

Question 22

Pelvic scan: where is fluid seen in women?

Answer 22

Inferiorlateral to bladder and also under the uterus (which is the pouch of douglas).

The uterus is free floating so fluid can be seen anteriorly and posteriorly.

Question 23

___% of women with ectopic pregnancys are misdiagnosed at first contact

Answer 23

40%

Question 24

What is the rate of ectopic pregnancy?

What is the rate of heterotopic pregnancy?

Answer 24

ectopic - 1:80

heterotopic - 1:30,000

Question 25

In women undergoing fertility treatment what is the rate of heterotopic pregnancy?

Answer 25

up to 1%

Question 26

What must be seen to diagnose an intra-uterine pregnancy? (3)

Answer 26

1. Decidual reaction
2. Gestational sac (pocket of amniotic fluid)
3. Yolk Sac (double ring sign - is echogenic layer within the gestational sac) - usu detected by 6-7 week transabdominally and 5 weeks transvaginally

• Fetal pole (see crown and rump) and cardiac activity trump the above and confirms an IUP (usu seen >6 weeks)

Question 27

What are the 2 sources of error mentioned with regards to the obstetrical u/s

Answer 27

1. Beware of psuedo-gestational sac - in ectopic this can form but will not have the yolk sac. So make sure the 3 things are seen
2. Extra-uterine pregnancies

Question 28

Define:

1. Echogenic, echolucent, hyperechoic, hypoechoic

Answer 28

Echogenic: A material that produces echoes (i.e. U/S waves bounce off). The more
echogenic a substance is, the whiter the image it produces on the screen.

Echolucent: A material that does not produce echoes (i.e. allows U/S waves to pass
through). The more echolucent a substance is, the blacker the image it produces on the
screen.

Hyperechoic: More echogenic (therefore whiter/brighter) than surrounding tissue.

Hypoechoic: Less echogenic (therefore darker) than surrounding tissue.