abdomen, pelvis and GI system Flashcards
(29 cards)
imaging
advantages
- cheap compared to CT / fluoro
- non invasive / lose risk
- reasonable assessment of acute abdominal pain in hospital setting if correctly requested
disadvantages
- limited yield
- limited sensitivity and specificity
should be avoided for:
? constipation
? renal stones
non acute abdominal pain
gastrogafin
- oral contrast administered in the cases of adhesions bowel obstruction / ileus
- effective tool for demonstrating whether surgical intervention is necessary or not
- adhesion obstruction - due to previous surgery - preventing more surgery = good thing
- if there is passage of contrast though to the right colon in 24hrs, the obstruction does not require surgical intervention
- it acts as a dental laxative and anti-inflammatory
sigmoid volvulus
- twisting of the bowel causing obstruction
- tend to appear dilated
- coffee bean sign
large bowel obstruction
- large dilated bowel loops
- haustral folds not well visualised
- smooth bowel walls
small bowel obstruction
- dilated bowel loops but not as big as large bowel obstruction
- haustral folds more prominent
- usually more centrally located
fluoroscopy
advantages
- relatively cheap compared to CT / MRI
- relatively non invasive compared to surgery
- dynamic
- high temporal and spatial resolution
disadvantages
- less sensitive than CT / MRI for most conditions
- poorly tolerated by patients
- poor contrast resolution unless contrast is administered
barium swallow
- a dedicated examination of the pharynx, oesophagus and stomach and duodenum
- used for gastro-oesophageal reflux disease, difficulty swallowing and hiatus hernia
polyp
- small growths on the inner lining of the large intestine or rectum
- common, 1 in 4 affected
- more common in men than women aged 60+
- some develop into cancer
- risks include family history, colitis, crohns, overweight, smoking
gastrostomy
- tube inserted directly into the stomach through the abdominal wall
- for patients that cannot eat or drink and often have issues passing a NG tube down
2 main types:
1. percutaneous endoscopic gastronomy - a feeding tube inserted into the stomach using an endoscopy to identify the position
2. radiologically inserted gastrostomy - a feeing tube inserted using fluoroscopy to identify the position of the stomach
endoscopy
- oesophagi-gastro-duodenoscopy
- endoscopic retrograde cholagnio pancreatography
- flexible sigmoidoscopy
- colonoscopy
- colon capsule endoscopy
- virtual colonoscopy
CT
- best single modality for evaluating most chest and abdominal problems
- simple method for detecting and staging malignant disease and monitoring response
- useful in guiding interventions e.g. biopsy and drainage
- useful in obese patients compared with ultrasound
- high dose
- most scans require IV contrast
CT Colonography
- patient receives full bowel preparation plus one doe of oral contrast 12 hours before
- rectal catheter, CO2 insufflation of bowel
- prone and supine acquisition on scanner
- good global overview of intrabdominal pathology
- very relatable for detecting small colonic tumours and significant poles as the colon is prefers and distended
how is the procedure performed
- a small flexible tube is inserted into the rectum by about 5cm
- buscopan is administered through the cannula in the arm to prevent bowel spasm
- carbon dioxide is introduced to the bowel through the tube in the rectum which is down at a controlled rate by a insufflation machine
- scans are taken with the patient supine and prone
- contrast media may be injected during the supine scans
benefit vs risk
benefits
- minimally invasive
- MPR (2D + 3D)
- lower risk of perforation than conventional colonography
- reduced risks for patient who take blood thinners or have breathing problems compared to conventional colonography
- quicker than colonoscopy
- can image when bowel is narrowed or obstructed for any reason
- images offer more detail than a barium enema
- can detect abnormalities outside of the colon
risks
- small risk of perforation of bpwel
- ionising radiation
- contrast reaction
MRI
advantages
- non invasive
- can be tailored to answer specific problems
- no ionising radiation
- dynamic
disadvantages
- expensive
- lower resolution
intra-abdominal applications include
- MRCP - detecting bililary duct stones
- local staging of rectal cancer
- evaluating liver lesions
- evaluating Crohn’s disease extent and activity
ultrasound
advantages
- cheap, quick, reliable, non invasive
- no ionising radiation
- excellent for solid organs and biliary tree
- real time imaging for biopsies
disadvantages
- operator dependant
- quality may be degraded by air / fat
- not usually a good modality for evaluating bowel
excellent first line investigation for many abdominal problems such as
RUQ pain ? gallstones
renal colic
jaundice
liver imaging CT
late arterial phase - 35s - very bright aorta, small arteries in liver opacificed
portal venous phase - 70s - some aorta enhancement, portal veins opacificed, overall increased liver enhancement
delayed phase - 2-5mins
could be bolus tracked
hepatocellular carcinoma
- most common type of primary liver cancer
- occurs most often in people with chronic liver diseases such as cirrhosis caused by Hep B or infection caused by Hep C
- US first with CT/MR to confirm diagnosis
haemangioma
- most common benign liver tumour
- can vary in size
- 60% of cases have more than one present
- imaging used every 6-12 months to monitor
- if small and stable, no treatment is necessary
- surgery used to remove if rapid growth
- picked up with US, CT/MRI to confirm diagnosis
hepatitis
- usually the result of a viral infection or liver damage
- different forms known as A,B,C,E
- a highly contagious, mild illness, many infected and may not know, usually resolved with no treatment and causes no long term damage to the liver
- surveillance with US, where chronic cases present as scarring with coarse, echo bright texture
liver abscesses
- defined as a pus-filled mass within the liver
- can develop from injury to the liver, blood infection, abdominal infection
- may require drainage
cirrhosis
- scarring of the liver caused by long-term liver damage
4 stages of liver failure
1. inflammation
2. fibrosis - scar tissue begins to replace healthy tissues in the inflamed liver
3. cirrhosis - severe scarring has built up, making it difficult for the liver to function.
4. Liver disease … cancer
pancreas
- located in the abdomen behind the stomach and connected to the duodenum via the pancreatic duct.
- functions as a mixed gland so has both endocrine for the regulation of blood sugars and exocrine function that aid digestion
islet cells in the pancreas
- control the release of insulin and glucagon
- located below and behind the stomach
- islets of langerhans contain 3 types of cell:
alpha - produce glucagon
beta - produce insuline
delta - produce somatostatin
