GI Imaging Flashcards
What do the colors on a XRAY represent?
- White: Bone
- Gray: Soft tissue
- Black: Air
What is special about a KUB XRAY?
It has contrast
How much radiation is a CXR? CT Chest?
- CXR: 0.1mSv
- CT Chest: 7 mSv
70x the radiation!!!
0.1 mSv is like smoking a cig
Free air under the diaphragm
Air Ladder Effect due to SBO
What are the 2 common causes of free air under the diaphragm?
- Bowel perforation (Surgical emergency)
- Insufflation of gas during laparoscopy
They look the same, but one is an emergency
For someone with acute abdomen, what XRAYs are indicated?
- Upright CXR
- Supine Abd XRAY
What does fecal matter look like on XRAY?
Soft opaque tissue with internal mottled air
What XRAY is good to evaluate constipation with?
AP abd/pelvis in supine position
Add on erect and lat dec if concerned for complications.
What is echogenicity?
Ability of tissue to reflect or transmit US waves in the context of surrounding tissues.
What are hypo and hyperechoic? Anechoic?
- Hypoechoic: gray or darker, muscle/tissue
- Hyperechoic: lighter and brighter, air, fat, gas
- Anechoic: Black, fluid and blood filled structures
What does a gallbladder typically appear as in US?
- Smooth, thin walls < 2mm
- Anechoic lumen (bile filled)
>6m would be cholangitis
What does the biliary tree typically appear as in US?
- Narrow caliber < 6mm
- Uniform ductal walls
- CBD
What are the primary benefits of CT over XRAY?
- Good contrast resolution
- Slices allow for structures to be seen without being superimposed on each other
What are the 3 planes?
- Coronal: ventral and dorsal
- Sagittal: L/R
- Axial: Horizontal and Vertical
