Imaging techniques Flashcards
List the different types of imaging techniques
Plain film
CT
MRI
PET-CT
Ultrasound
What are the characteristics of a plain film image?
Mobile technology
Quick and cheap
Low does of radiation
Is not used in emergencies.
What is a plain film image?
Uses x-rays to produce an image or the bones, lungs or teeth to aid daignosis.
What are the characteristics of a CT scan?
Static donut shaped scanner
Relatively quick and cheap
Excellent anatomical detail.
Relativly high dose of radiation
Most exams require contrast.
Cross section images
What are some characteristics of an MRI?
Statis tunnel scanner
Long time to scan, 30 mins minimum
Excellent contrast resolution
No radiation
Does not need contrast
Cross section images
Realigns water molecules in the body to a magnetic field, can detect the level of spin required.
What are the characateristics of a PET-CT scanner?
PET provides metabolic information using a radiotracer
CT provides anatomical information
Relatively high dose of radiation
High rate of incidental findings.
What are the key characteristics of an ultrasound?
Mobile, only requires a probe and ultrasound jelly.
Quick and cheap
Can’t scan gas filled or dense structures
Quality depend on user
Sound waves.
How are densities reflected in x-rays?
Black is air
Dark grey is fat
Like grey is soft tissue
Murky white is Bones
Bright white is metal
How are densities shown in CT scans?
Black is air
Dark grey is fat
Light grey is blood
White is bones.
Explain how MRI images are interpreted?
Uses magnets and radiowaves to produce images
Map of proton energy, whiter areas have more energy
Two types of imagining T1 and T2
T1 - fat is bright white
T2 - fat and water are bright white.
Grey matter is lighter than white matter in T2 converse in T1.
What does PET-CT images look like?
Like colourful CT scans, similar to heat maps in appearance.
What does the densities on ultrasound show?
Fluid = anechoic (no echo) = black
Cartilage and muscle = hypoechoic signal = grey
Bones, fat and stones = hyperechoic signal = white.
