Abdo Radiology Flashcards
PET scans useful in what dx?
cancer
nuclear medicine uses what?
gamma rays
Who is Wilhelm Roentgen?
discovered x-rays in 1895
3 things that affect x-ray absorption:
thickness of tissue
density of tissue
Atomic number of tissue
increasing Atomic number will increase tissue absorption is by how much
the the 4th power
2 ways to improve on x-rays
introduce contrast increase sensitivity (CT scan)
2 kinds of contrast
barium (Atomic 56)
iodine (atomic 53)
2 ways of barium into the system
barium meal (hernias) barium enema (colon carcinoma)
What is ERCP?
Endoscopic retrograde cholangio-pancreatography?
What is Endoscopic retrograde cholangio-pancreatography?
injecting iodine into bile duct through a long ass scope via the mouth
What is Percutaneous Transhepatic Cholangiography?
injecting bile duct through the liver using fluroscopy
2 places to inject intravascular contrast medium:
intravenous
intraarterial
Why use intravascular contrast?
helps see kidney structures
Angiography is for what?
visualizing lumen of vessels
Intravenous contrast with biliary excretion is for what?
trace path of the billirubin like contrast from hepatocytes into bile ducts then CT it
What is the Hounsfield unit?
how much absorption to different tissues, an objective grayscale measuring tool
Radioissotope imaging involves what?
injecting intravenous radioisotopes that release gamma rays and recorded on ‘camera’
Example of radioisotope imaging?
radioisotope attached to bilirubin-like molecule to visualize gall bladder etc.
describe the wavelength and frequency of ultrasound
short wavelength high frequency (3MHz)
low or high frequency travels farther?
low
How does ultrasound produce image?
records echos derived from known speed of sound in tissues
ultrasound doesn’t work well through what?
bone and air in lungs
doppler is what?
perceived change in frequency due to relative movement of source and observer
what is doppler used for?
seeing blood flow velocity
MRI uses how many Tesla?
0.3 - 3.0 Tesla
1.5 T MRI is how many times earth magnetic field?
30 000 times
What is Magnetic Resonance Cholangio-Pancreatography
injecting pancreas vessels with contrast and then MRI image it.
MRI relies on what of the atoms?
non-random alignment and spin of Hydrogen atoms usually to get the magnetic moment
Can you see the edge of the psoas muscle on x-ray?
yes
Do we do barium enemas a lot these days?
Nope. normally endoscopy
How much % does portal vein vs. hepatic artery supply the liver?
portal vein: 75%
hepatic artery: 25%
What drains the liver? 3 things.
Hepatic Veins
Left
Middle
Right
What is the ‘newer’ divider for left and right liver?
middle hepatic vein to the gall bladder protrusion
