Imaging of the GI tract Flashcards
What are the different imaging methods used for the GI tract?
- Conventional: X-ray, fluoroscopy
- Ultrasound
- CT
- MRI
What is the 1st imaging investigation whenever a patient presents with acute abdomen?
X-ray
What is to be looked for in a chest x-ray?
- Gas
- Soft tissue
- Calcium - bright
- Foreign object - coins, batteries in children
How is gas seen in a supine x-ray film?
- Blobs of dark or lucent areas
- In erect x-rays the air looks level
What is the normal gas distribution in an x-ray?
- Stomach Lt upper portion
- Small intestine - 2/3 gas filled loops none larger than 2.5cm cenrally
- Large intestine mostly in distal portion i.e sigmoid colon and rectum. Peripherally and in lower portion (pelvis). Max diameter 5.5 cm, caecum the beginning of colon can be up to 8 cm
How do you know that gas in present in the small intestine?
Central, thin folds going across entire circumference (valvulae conniventis)
How do you know that gas in present in the large intestine?
Periphery, thicker and incomplete folds
What does small intestinal obstruction look like on conventioanal x-ray?
- Distended (>2.5 to 3 cm)
- Multiple central fluid levels
- Less gas or no gas in large intestine
What does large intestinal obstruction look like on conventional x-ray?
- Distended gas filled loop or air fluid levels at the periphery
- Caecum over 9 cm, rest over 5/6 cm
- Look for haustrae to differentiate
- Less or no gas beyond the level of obstruction
What are haustrae?
Incomplete folds of large intestine (obstruction)
What does gas in the wrong place or outside the intestine and stomach mean?
- Intestinal perforation
What can intestinal perforation be due to?
Outside injury or operation (emergency)
What is the clinical name given to gas outwith the intestines?
Pneumoperitoneum
What does a coffee bean like
sigmoid colon indicate?
- Sigmoid volvulus
- Loop of sigmoid colon wraps around itself
What can abnormal calcifications be due to?
- Stones: gall/ureteric/bladder
- Calcification in vessel wall (age related atherosclerosis, diabetes, aneurysm)
- Calcification in organs (pancreas, renal cyst, uterine fibroids)
What can happen as a result of chronic pancreatitis?
Pancreatic tissue can become necrosed and calcium can deposit on it
What can happen as a result of constipation which can shoe up on x ray
Brightness in large intestine as a result of calcium deposits collecting on stool
What does severe abdominal pain with history of gall stones and intestinal obstruction?
Gallstone ileus
When can barium swallow have limited use?
After advent CT and MRI
What is barium enema?
- X-ray exam that can detect changes or abnormalities in colon
- The barium is injected into rectum through a small tube
- Coats walls of LI
- Gas fills the colon
What does barium ehich has all been collected at the lower oesophagus indicate (beak-like appearence)?
Achalasia
Ultrasound with help of colour doppler helps assess what?
Blood supply to an organ
What can ultrasound be useful for?
- Gall stones and gall bladder inflammation
- Quick assessment of abdomen in trauma cases (FAST scan)
- Serial assessment of foetal well being
- Complications related to pregnancy
- 1st line test to assess uterus and ovaries
- Acute abdomen in children
- Dynamic assessment (abdominal and inguinal hernia)
Round fluid-filled (black) structure in ovary is?
Cyst
