Abdominal surgery and imaging Flashcards Preview

Z MD1 GI block > Abdominal surgery and imaging > Flashcards

Flashcards in Abdominal surgery and imaging Deck (18)
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medium used for intravasular contrast medium



what is the principle of radioisotope imaging

- attached to particular molecules that are introduced into the body - emit gamma rays that are recorded by a gamma camera


distribution of iodine when injected into the body

distributed through the blood vessels --> some becomes extravascular --> then goes to kidneys --> excreted


principle of ultrasound imaging

machine produces thin sectional images using echoes returned form tissue interfaces (some will reflect and some will go to reflect at other surfaces)


why do you need gel between the probe and the skin when using Ultrasound

if the high frequency ultrasound hits air it bounces back


principle of MRI

put patient in a very strong magnetic field - aligns the atoms of the body momentarily to the same direction. Then stop the magnitism and listen for the resulting signal from the change in magnitism back to "normal"


what are the main reasons for surgery of the small bowel

- obstruction due to adhesions, herniae - utility of small bowel - ileal pouch operation, ileostomy - Meckel's diverticulum - Ileal Crohn's disease


what are the main reasons for surgery of the stomach

- hiatus hernia - Barrett's oesophagus - helicobacter in antrum - duodenal ulcers - CD in duodenum - achalasia


principle of radioisotope biliary imaging

radioisotope is attached to a molecule which is recognized as like bilirubin --> excreted to liver and then into the gall bladder --> duodeum


doppler effect

a perceived change in frequency of waves when there is relative movement between the generator of the sound and the observer of the sound


types of diagnostic radiology (5)

x-ray -gamm rays - ulrasound - MRI -PET


absorption of an x-ray beam in tissues depends on:

- thickness of the tissue - density of the tissue - atomic number of the tissue (to the 4th power)


what physiological and pathological features cause a shadow on ultrasound

physiological - lungs pathological - gall stones


how do we improve on the natural differences in Xray absorption

- alter the absorption (use a radiographic medium) - measure the absorption by a more sensitive method


how many times stronger is the MRI magnetism compared to earths gravity



what are the main reasons for surgery of the colon and rectum

- COLORECTAL CANCER - diverticular disease - ulcerative colitis and Chron's colitis


wave length and energy of xrays

short wavelength and high energy ( in between UV and gamma rays)


common reason for surgery on the gallbladder

gall stones +/- inflammation