EDE Flashcards
How much fluid is normally in the pericardium?
50cc
How much fluid is needed to see a pericardial effusion posteriorly in systole?
~100 cc
How much fluid is needed to see a pericardial effusion posteriorly throughout the cardiac cycle?
100-300cc
How much fluid is needed to see a pericardial effusion anteriorly and posteriorly?
> 300cc
How much fluid can the pericardium accommodate (acutely) before there is hemodynamic compromise?
100-200 mL
If it accumulates slowly thats when you can see 300+ mL
Name causes of false positives on Cardiac EDE?
- Epicardial fat
How do you distinguish epicardial tissue from an effusion?
It appears anteriorly first and dissapears posteriorly where an effusion would collect posteriorly first.
In Aorta scan how can you distinguish aorta from IVC?
- Wall thickness
- Compressibility
- Variation with resp (IVC will vary)
- Sniff test (IVC will change) or can bear down
What is one scenerio where the sniff test will be falsely negative?
If there are high right sided pressures like having a tamponade
How big does the aorta have to be to not have a AAA?
<3cm
Why isnt EDE able to detect a AAA rupture?
It does not visualize the retroperitoneum so will not see any free fluid.
In respect to AAA’s what is the 95% rule? (that I made up)
95% are fusiform (saccular are less common), 95% are infrarenal, 95% rupture over 5cm and 95% rupture into the retroperitoneum.
What is Morisons pouch
The hepatorenal space
Why is the RUQ the best view?
- 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)
The hepatorenal view alone will detect ___% of clinically significant cases
80%
How much fluid is needed for EDE to detect it in the abdomen?
Most studies state 500mL, some states 900mL
What are causes of false positives on the LUQ scan? (5)
- Perinephric fat (often bilat and symmetrical and more echogenic)
- Ascities
- Peritoneal dialysis fluid (CAPD fluid)
- Ovarian cyst rupture
- Urine from rupture bladder
What are 3 sources of false negatives on the Abdominal scan?
- Adhesions - can cause loculations of fluid to accumulate. If pt has abdomen scars dont trust EDE
- Delayed presentations (12-24 h after bleed, blood can clot and look more echogenic)
- LUQ variability
- blood doesnt only accumulate in splenorenal interface but also medial and superiorly
What are the pelvis scans visualizing?
In men the rectovesicular pouch and in women the rectouterine pouch (pouch of douglas)
What are causes of false + in pelvis scan in women?
Normally can have physiological fluid
Pelvic scan: why in men is fluid only see anteriorly?
The rectum is retroperitoneal in men so will only see ‘mickey mouse ears’ inferior + lateral to the bladder
Pelvic scan: where is fluid seen in women?
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.
___% of women with ectopic pregnancys are misdiagnosed at first contact
40%
What is the rate of ectopic pregnancy?
What is the rate of heterotopic pregnancy?
ectopic - 1:80
heterotopic - 1:30,000
In women undergoing fertility treatment what is the rate of heterotopic pregnancy?
up to 1%
What must be seen to diagnose an intra-uterine pregnancy? (3)
- Decidual reaction
- Gestational sac (pocket of amniotic fluid)
- 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)
What are the 2 sources of error mentioned with regards to the obstetrical u/s
- 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
- Extra-uterine pregnancies
Define:
1. Echogenic, echolucent, hyperechoic, hypoechoic
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.
