Introduction to investigative procedures Flashcards
Describe plain abdominal X ray?
Gut is visible when there is gas in it
Describe bowel contrast radiology?
For examining Upper GI tract, barium sulphate suspension given orally
X ray fluoroscopic screening
Large bowel examined when contrast given rectally
Small bowel examined after barium meal
Describe biliary contrast radiography?
Cannula inserted and contrast injected into common bile duct and pancreatic duct
What is urography?
Used for examining the kidneys and urinary collecting systems
Uses intravenous contrast which gets concentrated and excreted by the kidneys
What is angiography?
Intravenous or intra arterial injection of a contrasted medium
Arteriogrphy is in the lower limb with a catheter into the femoral artery
What are the general principles of CT?
Series of thin transverse slices
When would CT be used?
For investigating areas difficult to examine with normal radiography (pancreas) or staging disease (lymphomas), also used for guiding needles during biopsy
What are the principles of MRI?
Powerful electromagnetic field is applied to the body aligning the protons of all the hydrogen nuclei
Protons are excited by pulses of radiowaves which causes them to resonate, emitting signals
What is ultrasound?
Non invasive, painless, safe
Transducer transmits and receives ultrasound
Brightness proportional to the sound reflectivity of the tissue interface
When would ultrasound be used in surgery?
Distinguish between solid and cystic lesions
Detect abnormal masses or fluid
Measuring physical dimensions eg aneurysm
What is bone scanning?
Phosphate based agents labelled with technetium are taken up by areas of increased bone deposition and resorption
Useful for suspected bone metastases, fractures, osteomyelitis and bone disease
What is flexible endoscopy?
Viewing bundles and flexible tips allow over 100 degree angle
What is a PET scan?
Positron emission tomography
Detects gamma rays emitted by positron emiting radionucleotide tracer introduced into the body on a biologically active molecule (usually an analogue of glucose)
