deck_1672100 Flashcards
Give five different types of imaging used to investigate the GI tract
• Plain x-rays • Contrast studies • Ultrasound • Cross-sectional imaging • Angiography
Give two types of x-rays
• Abdominal x-ray • Erect cheat x-ray
Give four types of contrast studies
• Barium swallow • Barium enema • Barium meal/follow through • Water soluble contrast studies
Give two types of cross sectional imaging
• Computed tomography • Magnetic resonance imaging
What are the risks of imagine?
• Radiation ○ Carcinogenesis ○ Genetic ○ Developmental risk to foetus
What is a contrast study used for?
• Defining hollow viscera
Give a water soluble contrast
• Iodine used
What is a barium enema used for?
• Study where contrast medium is inserted rectally
What is ultrasound?
• Use of sound waves to generate an imahe • Frequency above audible range of human hearing Usually 2-18 MHz
What are the advantages of ultrasound?
• Cheap compared to CT and MRI • Portable • Highly user dependent
What can ultrasound be used for?
• To determine if patient has gall stones • See if common bile duct inflated • Liver, protal vein and appendix
What is GI angiography?
• Injection of radio-opaque contrast agent intravenously and then using various methods to capture the image • Used for both bleeding and ischaemia to allow visualisation of the GI tract
Give four key features of an abdominal x-ray
• Stomach • Small and large bowel • Soft tissues • Bones
Give 6 soft tissues that can be visualised on an abdominal x-ray
• Liver • Spleen • Kidneys • Psoas major • Bladder • Lung bases
When are the intestines visible?
When filled with gas
When are the intestines not visible?
• When filled with fluid
Give four common reasons for requesting an abdominal x-ray
• Acute abdominal pain • Small or large bowel obstruction • Acute exacerbation of IBDRenal colic
What are the circular folds of the small bowel called?
• Valvulae conniventes • Appear as lines that appear to cross the whole of bowel lumen
Where is the large bowel seen on an abdominal x-ray?
• Periphery • Possible to see haustra on the x-ray
What does faeces look like on an x-ray?
Clouds in the lumen
What is the rule of 3/6/9 in checking the small and large bowel for gas obstruction?
• Small bowel is said to be dilated when it is greater than 3cm • Large bowel when it is greater than 6cm • Caecum (when the ileocaecal valve is working) is said to be dilated when it is >9cm
What does small bowel obstruction usually present with?
• Vomiting • Mild distension • Absolute constipation is a late feature
Why may you vomit earlier in small bowel obstruction?
• Obstruction closer to mouth
Give four causes of small bowel obstruction
• Adhesions • Hernias ○ Inguinal, femoral, incisional • TumoursInflammation
What do people with large bowel obstruction present with?
• Abdominal pain and distension, with constipation as an early feature • Vomiting and faeculance is a late feature
What is the abdominal pain like in large bowel obstruction?
• Colicky, but not as frequent as small bowel obstruction
Give five causes of large bowel obstruction
• Colorectal cacrinoma • Diverticular stricture • Hernia • Volvulus • Pseudo-obstruction
What is a volvulus?
• This is when a viscera twists around itself or the mesenteryMost common is a sigmoid/caecum volvulus
What happens when a volvulus occurs?
• Twisting occurs and the enclosed loop of bile dilatesIncreases risk of perforating or cutting of its blood suppl
Name 6 abnormalities which can be visualised on an x-ray
• Pancreatitis • Aneurysms • Nodes • Bones • Artifacts • Foreign body • Kidney stones
What is an erect chest x-ray useful in diagnosing?
• A perforated bowel
Give 6 causes of a perforated bowel
• Peptic ulcer • Diverticular disease • Tumor • Obstruction • Trauma • Iatrogenic
Why does the chest x-ray need to be erect for a perforated bowel?
• The diaphragm will only be separated from other viscera by the air rising to the top
What is normally found in the peritoneal cavity?
• Small amount of fluid
What is an abdominal CT?
• High dose radiation • Good spatial resolution (Poor contrast compared to MRI)Use of IV or oral.rectal contrast
What is MRI?
• No radiation • Good spatial and contrast resolutionTime consuming
What is an MRI scan used to visualize the gall bladder and biliary tree?
• Magnetic resonance cholangio-pancreatogram
