Lecture 6- Abdominal & Pelvic Imaging Flashcards
what are 4 quadrants? what is in each?
- RUQ: Liver, stomach, gallbladder, duodenum, R kidney
- LUQ: Stomach, pancreas, L kidney, spleen
- RLQ: appendix, R ovary
- LLQ: colon, L ovary
9 abdominal divisions
- Superior: R hypochondric; epigastric; L hypochondric
- Middle: R lumbar; umbilical; L lumbar
- Inferior: R iliac; hypogastric; L iliac
what is in the 9 regions?
- R Hypochondriac: liver, gallbladder, right kidney, and portions of the small and large intestine
- Epigastric: portions of the liver, stomach, pancreas, duodenum, spleen.
- L Hypochondriac: spleen, large/small intestines, L kidney, pancreas, stomach
- R Lumbar: ascending colon, small intestine, and R kidney
- Umbilical: duodenum, small intestine, transverse colon.
- L Lumbar: descending colon, small intestine, L kidney
- R Iliac: appendix, cecum, ascending colon, small intestine.
- Hypogastric: bladder, portions of the sigmoid colon, small intestine, reproductive organs
- L Iliac: sigmoid colon, descending colon, small intestine
three division of the abdomen?
- foregut
- midgut
- hindgut
what is the foregut?
- consists of the distal end of the esophagus, stomach, portion of the duodenum
- includes liver & gallbladder
- Celiac trunk is the principal artery which supplies the foregut and arises from the abd aorta
what is in the midgut
- distal half of duodenum, jejunum, ileum, cecum, ascending colon, proximal half of transverse colon
- branches of the sup mesenteric arteries/veins provide primary vascular supply
what is in the hindgut?
- consists of the distal half of transverse colon, descending colon, sigmoid colon, proximal third of rectum
- supplied by inferior mesenteric artery
what are the 4 lobes of liver? where are they?
- Right lobe: positioned to the R of the IVC and gallbladder
- Left lobe: positioned to the L ligamentum teres
- Quadrate lobe: positioned anterior to portal triad
- Caudate lobe: positioned posterior to the portal triad
retroperitoneal structures
- Suprarenal (adrenal) glands
- Aorta + IVC
- duodenum
- pancreas
- ureters
- colon (ascending/descending)
- kidneys
- esophagus
- rectum
what is retroperitoneum
an anatomical space located behind the abdominal or peritoneal cavity
what is the mesentary
a fold of membrane that attaches the intestine to the wall around the stomach area and holds it in place
what is the peritoneum
the serous membrane that lines the abdominal cavity
what muscle is very easy to see on xray? what can it help you find?
- psoas muscle
- ureters
label the anatomy of the CT slices in the ppt
ok
steps to viewing abdomen radiographs
- position it correctly- R marker in right spot, head up
- view as a whole for abnormalities
- view systematically (liver/spleen, psoas shadows, renal contours, calcifications, intestinal gas patterns, bones
common indications for requesting conventional abdominal radiographs
- assess bowel gas patterns
- hx of kidney stones to evaluate positioning
- screening test for non-localized abd pain
- look for radiopaque FBs
abd radiograph views
- AP view: most frequent, pt is supine
- upright: useful for detecting free air/air fluid levels in intestines
- decubitus: free air if pt can’t stand
- prone: detects air in rectum/sigmoid
what do abd series include?
- AP view
- prone or lateral rectal view
- upright or decubitus view
- CXR may be included
which kidney is lower? the spleen is the same size as?
- R kidney lower than L kidney
- spleen= size of L kidney
non pathologic calcifications that can be found on abd xray
- bones
- mesenteric lymph nodes
- phleboliths
pathologic calcifications in abd imaging
6
- cholelithiasis
- nephrolithiasis
- appendicolith
- pancreatitis
- arterial calcifications
- uterine fibroids
visibility of gallstones vs urinary calcli?
- gall: only 10% of all stones
- 90% of urinary calculi are visible due to high calcium content
what are phleboliths
- found in lower half of pelvis
- 1 cm of less in diameter
- more common in women
- small blood clots in a vein that harden over time due to calcification
describe normal gas pattern in bowels
- small amount of gas in stomach & small intestine
- always air in rectum or sigmoid colon w/ varying amounts of air in rest of colon
- CT most sensitive for identifying gas patterns
what is generalized adynamic ileus
- loss of intestinal motility
- increased gas throughout GI tract
- gas in rectum
- # 1 cause is post-op
clinical picture of generalized adynamic ileus
4
- hypoactive bowel sounds
- bowel distention
- +/- tendernes
- no cramping
describe small bowel obstruction
- mechanical obstruction of the small bowel
- “stacked coin”, dilated loops of small bowel
- little to no gas in colon, depends on timing
- # 1 cause is adhesions
describe large bowel obstruction
- mechanical obstruction of large bowel
- dilated colon proximal to the obstruction w/ no air distally
- absence of gas in rectum
clinical picture of LBO
3
- abd distension
- severe cramping
- pain
differentiate distended bowel and dilated bowel
- distended: air filled but still normal size
- dilated: air filled beyond normal size
how can large bowel be idetnified?
haustra- irregulary spaced soft tissue folds that do not usually transverse the width of the colon
describe sigmoid volvulus
- type of LBO
- occurs mostly in elderly pts w/ hx of constipation
- redundant mesentery twists on itself which causes obstruction
- classic appearance: inverted “U” projecting out of the pelvis
causes of pneumoperitoneum
3
- caused by rupture of hollow viscus
- perforated ulcer, diverticulum, carcinoma, appendix
- trauma or abd surgery
how to evaluate for pneumoperitoneum
upright or decubitus view
radiographic signs of pneumoperitoneum
- air under diaphragm on upright view
- air on both sides of bowel wall (Rigler sign)
- falciform ligament visible on supine view
barium contrast studies visualize what in upper GI?
- esophagus
- stomach
- small intestine
barium contrast studies visualize what in enema?
colon, not widely used
abd ct what contrast?
- oral contrast used for most except:
- trauma, vascular, stone search
when is barium contraindicated?
perforation,allergy, recent surgery
what does double contrast mean?
- use of pos an dnegative contrast agents to increase sensitivity of exam
- pos contrast: barium
- neg contrast: air, CO2
what can double contrast studies help with?
- detection of polyps and colorectal cancer
- f/u screening for post-op colorectal cancer
- evalulation of diverticular disease
- failed colonoscopy
- investigation of non-specific abd pain
when is double contrast study contraindicated?
- toxic megacolon
- pseudomembranous colitis
- imminent rectal bx +/- 7d
RUQ pain
1st choice dx, imaging modality, other causes
- cholecystitis
- other: peptic ulcer disease, choledocholithiasis, acute hepatitis, liver abscess, RLL pneumonia
- Imaging: first choice is US, CT second, CXR PRN
LUQ Pain
ddx, imaging modalitis
- least common quadrant to report pain in
- ddx includes splenic infarct (CT), splenic hemorrhage (US, CT), LLL pneumonia (CXR), PUD (endoscopy)
RLQ pain
1st choice dx, imaging modality, other causes
- most common: appendicitis
- ddx: diverticulutis, urinary calculi, IBD, gynecologic dx
- imagine: CT first choice, US in children, women of child-bearing age, preg women
signs of appendicitis on imaging
- thickened appendix (>10mm goes to OR; < 6mm r/o)
- appendicieal wall hyperenhancement
- focal cecal thickening
- periappendiceal inflammation
- appendicolith (10% of pts)
LLQ Pain
1st choice dx, imaging modality, other causes
- top cause is diverticulitis
- ddx: perforated colon CA, urinary calculi, gynecologic diseases
- Imaginge: CT best overall; US for children, women of child-bearing age, preg women
Flank Pain
1st choice dx, imaging modality, other causes
- most common cause is urinary calculi
- ddx: pyelonephritis, renal infarct, diverticulitis, appendicitis, pancreatitis, cholecystitis, ovarian masses
- imagine: CT, US can be used as initial test
Midepigastric/Back Pain
ddx, imaging
- ddx: pancreatitis, aoritc dissection, aortic aneurysm rupture, urinary calculi, bowel obstruction
- imaging: CT, if suspecting PUD do upper GI
gynecologic causes of lower quadrant/pelvic pain
ddx, imgaing
- ddx: PID, ruptured ovarian cyst, ectopic pregnancy
- imaging: US
what does apple core appearance mean?
some type of colon cancer is “eating” away at the lumen of the bowel leaving on the “core” of the bowel intact
what does lead pipe interpretation mean?
loss of haustra and narrowing of the colon which progresses proximally
suspect ulcerative colitis
go to ppt and fill out chart
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