Imaging Flashcards
how are protons arranged in an MRI?
magnetic fields align all protons in one direction
what happens when radiofrequency pulses are fired in an MRI?
causes the protons to be displaced
how does an MRI produce and image?
once the radiofrequency impulses are turned off, depending on the quicklness of of the displaced protns are at re-aligning and producing different wavelengths of gamma ray which are detected into images
what are benefits and disadvantages of MRI (with disadvantges state how it affects certain patients)
benefits - extreme detail
disadvantages - slow , expensive
affects patients as it can be clostrophobic and cant use with patents that have metal e.g pacemaker
what is CT good for and what is MRI good for?
CT- viewing boney detail and organs
MRI- soft tissue
does MRI use radiation?
no it uses magnetic field
CT uses radiation
what does MRI stand for?
magnetic resonance imaging
what contrast is used to pick up vascular lesions
godolinium
what do PET/SPECT scans show?
metabolic things
how would you scan for glucose metabolism?
radioactively tagged glucose analogue
pick up with a PET/SPECT scan
what are the benefits of SPECT
produces 3D images and is cheaper than PET
why is gel applied to a mother to take an ultrasound for her child
ultrasound waves find it difficult to travel through air. the gel is a liquid so they travel more easily
Why do different anatomical structures appear in different shades of grey/black/white on an x-ray?
x-rays absorb more on soft tissue & bone than abdomen or air
what colour is barium on traditional radiography and digital radiography?
traditional barium is white on colour
digital barium is black
what do the barium tests - barium follow through , barium swallow and meal , barium enema highlight in the body
barium swallow & meal- oesphoagus
barium enema- large bowel
barium follow through - small bowel
