Review Flashcards
Contrast agent for MRI?
Gadolinium
Contrast agent for UGI/LGI for GI tract (oral or rectal)?
Barium
Contrast base for IV or Intra-arterial?
Iodine based
What are 3 studies you would use IV/IA contrast?
Urinary studies (IVP, cystogram, urethrogram)
Angiogram
CT
Risk with Gadolinium contrast?
Risk in renal failure –> nephrogenic systemic fibrosis.
Indications for IVP?
Hematuria
Recurrent UTI
Anatomic variants
Cancer
Complications with barium based contrast for GI tract?
Inflammatory reaction if it leaks into the peritoneum.
Constipation - drink plenty of liquids after.
For the water soluble iodinated version: thinner, less coating
Complications include:
Dehydration
Hypovolemia
Diarrhea
Aspiration into lungs (pulmonary edema, pneumonitis)
Hypersensitivity esp with asthma or allergy to iodine.
Spiral or helical CT are good for..?
Diagnosing pulmonary embolus
Rapid evaluation of blunt trauma
What will an MRI of the head show?
Blood vessels
Embolic events
Nerve injuries
What will an MRI of the chest show?
Cardiac vessels and tissues.
Breast masses.
Blood
Aneurysms
Circle of Willis
MRI
Does a brain bleed show up better in an MRI or CT?
CT
Do lungs show up better in an MRI or CT?
CT
Do ligaments/tendons show better in and MRI or CT?
MRI
Does the spinal cord show up better in an MRI or CT?
MRI
Does a brain tumor show up better in an MRI or CT?
MRI
Limited uses of MRI?
Implanted defibrillators/pacemakers
Cochlear implant
Clips on brain aneurysms
Allows visualization of the hepatobiliary and pancreatic systems.
Magnetic Resonance Cholangio-pancreatography (MCRP)
In an MCRP, slow flowing fluid such as bile or pancreatic appears very ______ compared to solid tissues and faster flowing blood appears ______.
Advantage of an MRCP?
Bright
Dark
No contrast needed
Allows visualization of the blood vessels to study flow and function.
Most common organs studied are brain, kidney, aorta, legs.
Magnetic Resonance Angiography (MRA)
How is contrast injected for an MRA?
IV rather than intra atrial
Contrast is gadolinium
Describe hot and cold nodules on a thyroid scan.
“Cold” nodules (light) on a thyroid scan are:
Benign or malignant
Risk of cancer in a cold nodule is 10-15%.
Risk of cancer in a “hot” nodule (appears dark) is even lower. “Hot” indicates it is functioning (might be hyperthyroidism).
Lung cancer is better seen..?
With PET/CT than with CT alone
In regards to breast cancer, what is the genetic mutation inherited?
BRCA 1 or 2
4 main things of mammography findings?
Masses
Calcifications
Asymmetry
Distortion
Echogenic/hyperechoic/sonodense
White (stones, bones, pericardium)
Echopenic/hypochoic/sonolucent
Dark gray, lack of reflectiveness (kidney, spleen, uterus)
Anechoic
Black, No reflectiveness (unclotted blood in vessels)
Clarity of image, ability to discern one structure from another.
Resolution
Concept behind how sound waves are made
The ability of certain materials to generate an electric charge when they are placed under vibrations/mechanical stress.
Piezoelectric effect
Both a transmitter/pulser and receiver
U/S transducer
Modes on an U/S?
A mode - amplitude, simplest and oldest form.
B mode - brightness, no motion, 2D, looks at structures
D mode - Doppler, color, velocity, direction of blood flow, clots, cardiac issues, valve dysfunction (BART, blue away red towards)
M mode - motion, d mode with color
Focal irritation of bowel loops occurs due to inflammation of an adjacent organ.
Localized ileus (sentinel loops)
Radiological findings in functional ileus?
2-3 persistently dilated small bowel loops or cecum.
Gas, air fluid levels in sentinel loops.
Gas in rectosigmoid vault.
Radiological findings for Generalized Adynamic Ileus?
Dilation throughout the bowel and often stomach.
Air fluid levels throughout the bowel, due to continued production of secretions.
Gas in rectosigmoid vault.
Dilation of many loops of small bowel proximal to obstruction giving rise to “step ladder” appearance.
Small bowel obstruction
Peristalsis continuing in a SBO sounds like…
High pitched, rushes, hyperactive
Inflamed gallbladder adheres to the duodenum. Gallstone gradually erodes through the gallbladder wall and into the bowl. If the gallstone is large enough, it ca obstruct the small bowel or the ileocecal valve.
Gallstone ileus (misnomer - actually a SBO)
Intestines twisting on itself producing the mechanical obstruction (most common in sigmoid)
Volvulus
Ionizing ration
X-ray, CT
Non-ionizing radiation
Ultrasound, MRI
Clinical use for Carbonic Anhydrous Inhibitors (CAI)?
Treatment of open angle glaucoma - decreases production of aqueous humor, by blocking carbonic anhydrase in the ciliary body of the eye.
Mountain sickness - works by decreasing the amount of CSF and pH of CSF where carbonic acid is responsible for secreting bicarb. Creates a mild acidosis resulting is hyperventilation.
