GIT Flashcards
What structures does the GIT include?
Lips
Mouth
Pharynx
Esophagus
Stomach
Sm intestine
Appendix
Colon
Anux
What is an advantage + disadvantage of imaging the GIT?
Pro: can evaluate peristalsis function with cine-clips
Con: hard to see due to gas
What are the bowel wall layers + SF’s?
- Mucosal surface/epithelium: innermost layer, echogenic
- Muscularis mucosa*: hypoechoic, thin + smooth
- Submucosa: echogenic, thickest, contains vessels + lymph channels
- Muscularis propria/externa*: hypoechoic, inner + outer layer of smooth muscle
- Serosa: outermost, thin layer on periphery, echogenic
(* if we can see on u/s)
What is the largest endocrine organ in the body?
GIT!
Functions of the GIT?
-Digestion (most in duodenum)
-Absorption
Measurements of bowel wall?
3-6mm when undistended
2-4mm when distended (often has shadows)
What is the easiest structure to see on u/s in the GIT?
Stomach (LUQ)
What are the parts of the stomach?
-Esophagus goes into top of stomach
-Fundus is top
-Body is middle
-Pylorus antrum is bottom (which moves chyme into duodenum)
What patient positions are best for imaging the stomach?
-LLD for fundus
-RLD for antrum + pylorus
Where do duplication cysts occur in stomach?
Greater curvature of stomach
(m/c women)
What do duplication cysts look like in stomach?
-Anechoic
-Inner echogenic rim
-Wide outer hypoechoic rim
-On greater curvature of stomach
What is the cause of gastric dilatation?
Obstruction
(affects gastric emptying)
What is gastritis + what causes it?
-Inflammation of gastric mucosa
-From infection, drugs, stress or autoimmune
What does chronic gastritis look like?
-Hyperplastic + inflammatory polyps
What does atrophic gastritis look like?
-Small mucosa (inner lining stomach)
(Precursor to gastric cancer)
What does emphysematous gastritis look like?
-Same as acute, but with small gas bubbles in wall
Does Crohn disease commonly affect the stomach?
No!
(m/c terminal ileum)
What is Crohn disease + who does it affect?
-Inflammation of all layers of bowel wall
-Unknown cause
-M/c in young adults
What does Crohn disease look like?
-Hypoechoic target lesion
-Very vascular walls
What is the m/c benign gastric tumour?
Leiomyomas
What do leiomyoma’s look like?
-Hypoechoic
-Oval/circular
-Possible necrosis
What does GIST’s stand for?
Gastrointestinal stromal tumours
(can be benign or malignant)
Where is the m/c place to have a GIST?
Stomach
(think stromal for stomach)
What do GIST’s look like?
-Hypoechoic
-Possibly hemorrhage or degeneration
What is the m/c type of gastric carcinoma?
Adenocarcinoma
(m/c males)
What does gastric carcinoma look like?
-Thick wall (target/pseudokidney sign)
-Mass with no peristalsis
-Can have ulcers
SF of lymphoma?
-Thick hypoechoic wall
-Rugal fold thickening
Most common site for primary lymphoma in the GIT?
Stomach
What shape is the duodenum?
C shaped
What are the 4 parts of the duodenum?
-Duodenal bulb (shortest part)
-Descending (inferior)
-Transverse (across)
-Ascending (superior)
Where is the duodenum, jejunum + ileum in the body?
-Duodenum is 1st portion
-Jejunum is middle portion (thickest)
-Ileum is 3rd portion (longest)
Measurement of wall thickness of small bowel?
Less than 5mm
(if collapsed + symmetric)
Measurement of small bowel?
Less than 3cm
Where/what is the appendix?
A tubular structure attached to the cecum with a blind end
What are some characteristics of the appendix?
-Compressible
-Possibly tortuous
-No peristalsis
Measurements of appendix?
-Less than 6mm AP (outer-outer)
-Less than 2mm wall thickness
What is McBurney point?
-Imaginary line from iliac spine to umbilicus
-Midpoint of line is where the appendix is located
What does blind end mean?
When you are scanning the appendix and all of a sudden it ends (is normal)
Where is the colon located?
Laterally on R/L sides + superiorly along liver margin
What are the 4 sections of the colon?
-Ascending
-Transverse
-Descending
-Sigmoid (end before rectum)
(colon is hardest to see on u/s)
What does a fluid filled colon indicate?
-Diarrhea
-Obstruction
(is abnormal)
What are the measurements of the colon wall?
Undistended: 4-9mm thick
Distended: 2-4mm thick
How should you approach an appendicitis exam?
-Start with AOC
-Next start at cecum and try to find it inferiorly
-Lastly extend into pelvic/endovaginal exam if still can’t find it
What is an ileus?
Pseudo obstruction from diminished mobility of bowel (no peristalsis anymore)
What does an ileus look like on u/s?
Stitches
What does obstruction of the small bowel look like?
-Bumpy
-Round
-Can see bowel folds
Lightbulb for intussusception?
-Children
-Sandwich sign in SAG!
-Circles in TRV
(looks like a cinnamon bun)
Cause of intussusception?
-Idiopathic in children
-Pathological mass in adults
Cause of a small bowel hematoma?
Duodenum immobility
Cause of edema in small bowel?
Swelling of valvulae conniventes (bowel folds)
Lightbulb for Crohn disease for small bowel?
-M/c ileum
-Diarrhea
-Thick bowel wall (5-15mm)
-Target sign!
Where does diverticulitis in small bowel m/c occur?
Distal ileum
What is the m/c benign + malignant tumours?
B = leiomyomas
M = leiomyosarcomas
How do GIST’s + lymphomas look different sonographically compared to the other malignant tumours?
GIST’s = exophytic
Lymphoma = affects the bowel wall
Who is m/c to get appendicitis?
-Men
-Aged 5-45 (mean age 28)
What is rebound tenderness?
When pain is greater at release of pressure, rather than when applying the pressure
SF of appendicitis?
-Target sign
-Greater than 6mm + 2mm wall
-Possible appendicolith/fecalith (looks like calcification in lumen)
-Non compressible
-No peristalsis
-Fluid
What are the 3 complications of appendicitis?
-Abscess
-Peritonitis (inflammation of lining of stomach)
-Rupture/perforation
What is a mucocele?
Distension of appendix due to mucus
SF of a mucocele?
-Similar to appendicitis but w/o signs + symptoms
-Anechoic lumen with some echoes present
What is pseudomyxoma peritonei?
-Rupture of adenocarcinoma tumour that produces too much mucin
-Mucocele hangs off end of appendix
(m/c from appendix primary carcinoma)
SF of NETS’s?
Hypoechoic mass with appendiceal TIP!
What is mesenteric adenitis + its SF?
-Inflamed lymph nodes
-Round nodes (instead of normal oval)
-Greater than 4mm
What affects the colon during obstruction?
Cystic fibrosis affects the bowel (ileum or prox colon)
What is the main difference b/w Crohn disease inn the colon + ulcerative colitis?
Crohn = only affects certain areas
Colitis = is continuous
(otherwise they look SF the same)
M/c location for diverticulosis in colon?
Retrosigmoid colon
Lightbulb for diverticulosis in colon?
-Low bulk/fiber diet
-M/c over 50 years old
Where is colorectal carcinoma m/c?
-Rectum is m/c
-Rectosigmoid colon is also common
