Radiological anatomy of head&neck region Flashcards
which medical imagine modalities are ionising modalities?
x-rays, CT, nuclear imaging
How does ultrasound work?
sound waves coming from probe are higher than frequency we can hear. higher end of frequencies to look at superficial structures and lower end of frequencies to look at deep structures.
sound waves are reflected or transmitted depending on their density. they will produce echoes. probe will emit and detect the waves, producing an image wave.
what are the enemies of ultrasound?
bone and air
what are the non-ionising medical imaging modalities?
ultrasound, MRI, endoscopy, doppler flow imaging
what are x-rays?
a beam of photons
body tissues attenuate x-rays to varying degrees
image captured on a screen or film
what is CT?
computed tomography - multiple x-ray beams fired together to simulataneously give a whole slice of the body. 3D view.
CT vs MRI scans
CT - bone is bright white
MRI - cortical bone is black; can see a lot more soft tissues better
air is black on both and rest are different shades of grey
both cross-sectional options
quick summary of US, X-ray, CT, MRI
US is fast safe dynamic versatile and has doppler (allowing you to see direction of blood flow)
Plain X-rays are super fast, low radiation dose, good for obvious pahtology, 2D hence limited
CT - fast, high radiation dose, gold standard imaging
MRI - slow, no radiation dose, ever increasing demand, 15mins to hours
what does a sunken or bulging suture mean?
sunken = suggests dehydration
bulging/full = raised intracranial pressure or inflammation (e.g., meningitis, hydrocephalis)
when does the anterior and posterior fontanelle close?
posterior closes early on within a couple months. anterior takes a year to 2 years.
why can you not take ultrasound through adult brain?
because there is bone all the way around
what happens to the metopic suture in an adult?
disappears because the frontal bones fuse together
what are the lines of the spine?
(anterior to posterior):
anterior vertebral line
posterior vertebral line
spino-laminar line
posterior spinous line
how should the lateral masses of C1 be?
should be equidistant from the odontoid peg of C2
mechanism of jefferson fracture
patient falls on head
causes a break in the ring of the vertebrae
