Flashcards in Overview of diagnostic imaging Deck (20)
What do x-rays show?
Variations in physical density
Physical basis - scintigraphy
Metabolic activity (i.e. physiologic not structural)
MRI - physical basis
MRI - shows ?
Ultrasound - physical basis?
High frequency sound
Uses - radiography - 3
Bone, pulmonary and abdominal gas
Spectrum of white/black - xrays
Making images that represent a section through the body
Making images representing the distribution of radioactivity injected into a patient (radiopharmaceutical injection into jugular). Carcinomas cause 'hotspots' of metabolic activity
How do you make MRI images?
Applying pulsed magnetic energy to the patient and collecting radiowaves that are emitted between pulses.
Uses - MRI in animals
Predominantly for neurological problems. Shows brain in much more detail than CT. Fat shows up as white.
Making images by firing pulses of high frequency sound into the body and collecting the returning echoes.
Is the spleen or liver more hyperechoic?
spleen (more echoes return from spleen than liver).
Appearance of urine on ultrasound?
Black (no echoes)
Uses - ultrasonography
-visualise internal vessels and gall bladder of liver
-differentiate bladder, lumen, prostrate and urethra
-determine if peristalsis in GIT is normal
Common indicated for imaging
Owener's view of problem -->refine problem --> system affected --> structural lesion (location) --> investigation may involve imagine (investigation less likely to involve imaging if a dysfunction is suspected)
Result of diagnostic imaging =?
Description of the gross morphological features of a condition. Sometimes these are characteristic of a specific disease. Often further tests (biopsy) are required for a definite diagnosis. Predominantly to aid diagnosis, may also be used to guide biopsy or facilitate treatment