Radiology of GI Tract Flashcards
mnemonic for CXRs
- A = airway
- B = bones
- C = cardiac
- D = diaphragm
- E = everything else
mnemonic for bone x-rays
- “ABCs”
- A = aligment
- B = bone
- C = cartilage
- S = soft tissue
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
3-way abdomen series
- upright PA CXR = MOST SENSITIVE FOR FREE AIR
- supine & upright abdomen
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
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
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
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
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.
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
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
Characteristics of US of abdomen
- used to evaluate abdominal organs and biliary system
- mostly: suspected appendicitis, some gallstones
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 ducta_l systems for evaluation of strictures, stones, and neoplasm
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
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
