Radiology GI tract Flashcards
- Recognize the systematic approach for interpreting abdominal radiographs.
Bones
Stones/calcifications
Gas
Mass
- Recognize free intra-abdominal free air on abdominal radiographs and computed tomography (CT) and describe how patient positioning affects sensitivity for its detection.
1
- Compare and contrast the different contrast agents used in GI radiology and the potential benefits, risks, and complications of each.
Air
Barium
-Thin (low density) and thick (high density) consistencies
-Better choice for exams to evaluate luminal obstruction
-Avoid upstream of a mechanical colon obstruction
Iodinated water-soluble
-Main indication = possible gut perforation
-Avoid high osmolality iodinated contrast (Gastrografin® -and Gastroview) in proximal GI obstruction => aspiration -can lead to pulmonary edema
- Explain the ACR Appropriateness Criteria to order appropriate imaging tests.
ACR website, click on symptoms, recommends modality and the evidence medicine behind it
looking for free air in abdomen, which decubitus is better?
put someone in decubitus laying on left side
what is best for looking for free air? upright cxr supine abd, upright abd
upright cxr
how do you tell difference b/n colon ans small bowel
small bowel-Valvulae conniventes (also called plicae circulares) are thin, circular, folds of mucosa, some of which are circumferential and are seen on an X-ray to pass across the full width of the lumen.
colon- haustra, Sacculations of the colon (formed by the longitudinal muscles (taenia coli) and circular muscles) = haustra of the of the colon. Haustral markings should not cross the entire diameter of the lumen
The retroperitoneal structures of the colon (ascending colon, descending colon, and rectum) are relatively constant in position. These are often more readily identified than the transverse colon or sigmoid colon which are more variable in position. If visible, the caecum is often the widest segment. It too has a variable position, but is most often confined to the right iliac fossa.
GI flouroscopy
Barium swallow Esophagram Upper GI Small bowel follow through (SBFT) Enteroclysis Barium enema
Biphasic Esophagram
Indications: dysphagia, odynophagia, heartburn
Evaluates: oropharynx, hypopharynx, esophagus, gastroesophageal (GE) junction
Pathology: reflux (common), hiatal hernia (very common), aspiration, neoplasm, esophagitis
Upper GI
Indication: epigastric pain, hematemesis, nausea, vomiting, guiac positive stools
Evaluates: esophagus, stomach, duodenum
Pathology: gastritis/duodenitis, gastric or duodenal ulcers, diverticula, benign or malignant tumors
Small Bowel Follow Through (SBFT)
Often done in conjunction with upper GI
Indications: inflammatory bowel disease (IBD), malabsorption, diarrhea, partial SBO, unexplained GI bleed
Evaluates: distal duodenum/duodenojejunal junction to ileocecal valve
Pathology: Crohn disease, lymphoma, tuberculosis (TB), sprue, adhesions, partial/intermittent obstruction
Enteroclysis
Not often done
Provides more anatomical detail than SBFT
Involves placing a tube in the jejunum and instilling methylcellulose or air after the barium
Can also be used with computed tomography (CT)
Evaluates: jejunum, ileum
Pathology: same as SBFT
Barium enema
Types and indications:
Double contrast: rectal bleeding, polyps, cancer, IBD
Single contrast: fistula or sinus tract, patient unable to tolerate or cooperate with double contrast study
Water soluble contrast (Gastrografin®): risk for intestinal perforation, therapeutic for disimpaction
Contraindications to any type:
Suspected acute perforation
Acute, fulminating colitis (toxic megacolon)
Immediately after biopsy
Ultrasound
Advantages: No ionizing radiation ✓ Safe in pediatric population and pregnant women Real time Portable in critical care units Disadvantages: Operator dependent Body habitus & intestinal gas can affect exam quality
Evaluation of:
Gallbladder (cholecystitis) and biliary system
Solid organ lesions; can also help differentiate between solid vs. cystic
Appendicitis (esp. in children and pregnant women)
Vascular flow evaluation (Doppler)
Image-guidance for procedures
Computed Tomography (CT)
Without IV contrast
Detection of renal stone or hemorrhage
With IV contrast
Ischemic, infectious, or inflammatory disease, trauma, tumor
Arterial, venous, portal venous, delayed phases of IV contrast
Enteric contrast: oral or rectal route
CT cholangiopancreatography
Risks related to IV contrast
Nephrotoxicity
Allergic reaction
Risks related to ionizing radiation
Tissue injury
Carcinogenesis
Pregnancy
Contraindication unless life threatening illness
Use other imaging test if possible, US and MRI
Pregnancy test (β-hCG) in females in productive age (refer to facility/hospital policies)
