10-02-23 - Imaging of the GI tract Flashcards
Learning outcomes
- Recognise the role that imaging can play within clinical evaluation and diagnosis
- Describe different types of imaging modality, including plain film, USS and CT
- Identify the contexts where different imaging methods may be used to assist clinical evaluation and diagnosis
What are the 2 conventional imaging methods? What are 5 other imaging methods?
- 2 conventional imaging methods:
1) X- ray
2) Fluoroscopy - 5 other imaging methods:
1) Ultrasound
2) CT
3) MRI
4) Nuclear medicine
5) Hybrid imaging
What is the first investigation in the case of acute abdominal symptoms?
What 4 things are we looking for on an X-ray?
- The first investigation in the case of acute abdominal symptoms is an X-ray
- 4 things are we looking for on an X-ray:
1) Gas
2) Soft tissue
3) Calcium – can form stones
4) Foreign object
What positions can x-rays be done in?
What are features of each?
What are 3 positions of normal gas distribution on x-rays?
- X-rays done in supine or erect position
- In supine film: Gas seen as blobs of dark or lucent areas
- In erect film: Air(dark)/ fluid(bright) levels seen.
- 3 positions of normal gas distribution on x-rays:
1) Stomach left upper portion.
2) Small intestine- 2/3 gas filled loops none larger than 2.5 cm centrally
3) 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
What are features of the small and large intestine?
What do these features allow us to do?
- Features of the small and large intestine:
- Small intestine: central, thin folds going across entire circumference (valvulae conniventis)
- Large intestine: periphery, thicker and incomplete folds (haustrae)
- These features allow us to determine if there is gas in the large or small intestine on x-rays
What are 3 features of small intestine obstruction?
- 3 features of small intestine obstruction:
1) Distended (>2.5 to 3 cm).
2) Multiple central fluid levels (if erect)
3) Less gas or no gas in large intestine.
What are 4 features of large intestinal obstruction?
- 4 features of large intestinal obstruction:
1) Distended gas filled loop or air fluid levels at the periphery
2) Caecum over 9 cm, rest over 5/6 cm.
3) Look for haustrae to differentiate between small and large intestine
4) Less or no gas beyond the level of obstruction
Why can gas abnormally appear around the intestine and stomach?
What 4 places should we look for gas in the wrong place in an x-ray?
- Gas can abnormally appear outside the intestines and stomach due to Due to intestinal perforation or because it is introduced from outside by injury e.g operation
- 4 places should we look for gas in the wrong place in an x-ray:
1) Below the diaphragm in erect film.
2) Surrounding the intestine (riglers sign: gas within and outside intestine outlining the intestinal wall).
3) Gas collection which looks of different shape (triangle, football).
4) Gas outlining the ligaments and muscles. - Gas below diaphragm in picture
Football sign blob of gas
Gas beneath diaphragm and triangular collection of gas
What is an aunt Minnie in radiology?
What is a sigmoid volvulus?
What is it shaped like?
- Aunt Minnie (plural Aunt Minnies) in radiology are a distinctive radiographic finding that is virtually pathognomonic
- A sigmoid volvulus is when the sigmoid colon twists on itself and becomes obstructed
- It is shaped like a coffee bean
What are 3 different types of abnormal calcifications that we can see on x-rays?
- 3 different types of abnormal calcifications that we can see on x-rays:
1) Stones: gall, renal/ ureteric/ bladder.
2) Calcification in vessel wall (age related atherosclerosis, diabetes, aneurysm).
3) Calcification in organs (pancreas, renal cyst, uterine fibroids).
- Gallstones/kidney stones in picture
Stones in kidney/ureter and bladder
Calcification in pancreas and uterus
Calcification in aorta (aorta normally cant be seen) and abdominal aorta aneurysm (AAA)
What is gallstone ileus? How can they occur?
- Gallstone ileus is a rare form of small bowel obstruction caused by an impaction of a gallstone within the lumen of the small intestine
- Can be caused by a gallstone coming down the common bile duct , or the gall; stone has perforated from the gallbladder into the intestine
- Gallstone ileus on picture
How can fluoroscopy be used to look at structure in the body?
What are 4 different barium examinations we can do in fluoroscopy?
Why is the use of fluoroscopy now limited?
- Fluoroscopy be used to look at structures in the body by getting the patient to swallow contrast (barium or thin water-soluble contrast)
- 4 different barium examinations we can do in fluoroscopy:
1) Barium swallow
* Looking at the oesophagus
2) Barium meal
* Looking at the stomach
3) Barium follow through
* Waiting for swallow to go into the small and large intestine
4) Barium enema
* Put contrast through a Foley’s catheter into rectum
- The use of fluoroscopy is now limited after advent of CT and MRI/ easy availability of endoscopy.
Barium swallow and barium meal
Barium swallow and barium enema
What is achalasia cardia?
What can it be caused by?
What is lead pipe colon?
What does it present as?
- Achalasia Cardia is a rare disorder that makes it difficult for food and liquid to pass from the oesophagus to the stomach
- It can be caused by a malfunction of the oesophageal sphincter
- The lead pipe appearance of colon is the classical barium enema finding in chronic ulcerative colitis
- The affected area presents as being very smooth with no haustrations
- Achalasia cardia and lead pipe colon in photo
Ultrasound of kidney and liver
Normal gall bladder and gallstone on ultrasound
Gallstones and gallbladder inflammation and normal gallbladder ultrasound
Ultrasound and 3D ultrasound of foetuses
Uterus, ovaries and stroma on ultrasound
Fibroid (non-cancerous growth on uterus) on uterus and normal uterus on ultrasound
Ovarian cysts and regular follicles and stroma of ovaries
What is intussusception?
How does it affect the functioning of the bowel?
- Intussusception is a serious condition in which part of the intestine slides into an adjacent part of the intestine.
- This telescoping action often blocks food or fluid from passing through.
- Intussusception also cuts off the blood supply to the part of the intestine that’s affected
What is pyloric stenosis?
What group of people does it affect?
What does it cause in babies?
- Pyloric stenosis is a thickening or narrowing of the pylorus, a muscle in the stomach.
- This problem happens to newborns.
- The full name of the condition is hypertrophic pyloric stenosis (HPS)
- Pyloric stenosis causes projectile vomiting and can lead to dehydration in babies
Loops of small intestine blocked by inguinal hernia and gallstone ileus on CT scan
Appendicitis on CT scan
Normal appendix and inflamed loop of small intestine in Crohn’s disease
Stone stuck in lower rend of common bile duct on MRI
Anencephaly on MRI
What is nuclear medicine used for?
- Nuclear medicine: Tc pertechnatate scan (Meckel’s scan) to identify the meckels diverticulum which can cause bleeding, obstruction particularly in children.
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