Radiology of GI Tract Flashcards Preview

DEMS: Unit 1 > Radiology of GI Tract > Flashcards

Flashcards in Radiology of GI Tract Deck (19):
1

mnemonic for CXRs

  • A = airway
  • B = bones
  • C = cardiac
  • D = diaphragm
  • E = everything else

2

mnemonic for bone x-rays

  • "ABCs"
  • A = aligment
  • B = bone
  • C = cartilage
  • S = soft tissue

3

Indications for abdominal x-rays

  • check placement of tubes (e.g. nasogastric)
  • check femoral central line placement
  • evalutaion for bowel obstruction
  • evaluation for free air
  • evaluation for foreign bodies

4

3-way abdomen series

  • upright PA CXR = MOST SENSITIVE FOR FREE AIR
  • supine & upright abdomen

5

Free air on abdominal xrays

  • upright PA CXR = most sensitive
    • look underneath diaphragm
    • most apparent under right hemidiaphragm
  • air will be located in the most non-dependent space

6

Systematic review of abdominal x-rays

  • Bones
    • fractures, dislocations
  • Stones
    • calcified stones
    • only 10% visible on plain films
  • Calcifications
    • @ wall/capsule of organs
    • artery wall plaques
    • phleboliths @ pelvic veins
  • Gas/air
    • @ stomach, small or large intestine
  • Bowel dilation = hallmark of obstruction
  • Masses

7

Evaluation of bowel obstruction on x-ray

  • bowel proximal to site of obstruction will distend and dilate
  • "3, 6, 9 rule"
    • small bowel =
    • transverse colon = < 6cm
    • cecum = < 9cm
  • bowel distended to anorectal jxn = fxnl obstruction
  • mechanical obstruction
    • early = dilated loops of small and large bowel
    • late = clearing of air distal to point of obstruction
    • large bowel obstruction ==> only dilated colon

8

Characteristics/types of GI fluoroscopy

  • = specialized x-ray technique; displays images in real time on video monitor
    • contrast agents used opacify lumen
  • Barium swallow
  • Esophagram
  • Upper GI
  • Small bowel follow through (SBFT)
  • Enteroclysis
  • Barium enema

9

Barium swallow characteristics

fluoroscopic-radiographic contrast exam of oral,

pharyngeal, and/or esophageal swallowing.

barium swallow can evaluate the 3 phases of swallowing: oral, pharyngeal, and esophageal

and structural and functional abnormalities of the oral cavity, pharynx, and esophagus.

10

Characteristics of upper GI/SBFT/enteroclysis

  • fluoroscopic-radiographic contrast exam that examines the esophagus, stomach, and duodenum
  • uses both single contrast and double contrast (air + contrast[barium]) techniques
  • small bowel follow through (SBFT) = evaluation of jejunum, ileum, and terminal ileum
  • enteroclysis = small bowel exam w/air and contrast injected in jejunum

11

Characteristics of barium enema

  • fluoroscopic-radiographic test to evaluate the colon and rectum

  • barium (+/-) instilled into patient

  • pt. moved to various positions to allow barium to travel retrograde

12

Characteristics of US of abdomen

  • used to evaluate abdominal organs and biliary system
  • mostly: suspected appendicitis, some gallstones

13

Characteristics of CT abdomen

  • widely used for evaluation of abdominal pain or GI problems
  • CT is good for evaluating intramural compoenent of bowel + evaluation of adjacent mesentery, omentum, peritoneal cavity, viscera
  • CT (and MR) cholangiopancreatography are employed in the assessment of the hepatobiliary and pancreatic ductal systems for evaluation of strictures, stones, and neoplasm

     

14

Contrast agents used in GI imaging

  • barium
    • used to opacify lumen and identify abnormalities on surface
    • contraindicated: upstream of colon obstruction, possible gut perforation
  • barium + air ("double contrast)
    • air = swallow CO2-producing crystals
  • iodinated water-soluble
    • use in possible gut perforation
    • avoid high osmolality in pts w/proximal obstruction
  • IV contrast
    • improves eval of bowel wall, solid organs, vascular structures
    • masks stones, subtle calcifications, hemorrhage
    • nephrotoxic + allergic rxn

15

Risk factors for serum Cr measure before IV contrast

Age > 60

• History of renal disease, including:

◦ Dialysis

◦ Kidney transplant

◦ Single kidney

◦ Renal cancer

◦ Renal surgery

• History of hypertension requiring medical therapy

• History of diabetes mellitus

• Metformin or metformin-containing drug combinations

  • pregnant patients = generally avoid interventional/high radiation studies or substitute US or MRI

16

MRI uses in GI evaluation

  • solid organs
  • biliary tract
    • heptobiliary and pancreatic ductal systems

17

Contrast use in MRI

  • IV contrasts are gadolinium-based
  • no nephrotoxicity but risk of nephrogenic systemic fibrosis in pts w/sever renal dysfxn

18

Angiography/IR use for GI evaluation

  • widespread for therapeutic purposes
  • used to dx:
    • GI bleeding
    • Biliary obstruction
    • Image-guided biopsy
    • Abscess drainage
    • Feeding tubes
    • Portal hypertension
    • IR oncology

19

Characteristics fo ACR Appropriateness Criteria

  • useful to choose appropriate imaging studies depending on the clinical presentation and variations