فحوصات محاضرة 1

• What are contrast media (CM)?

  Diagnostic radio-opaque substances of high density used to improve image resolution.
• Why are contrast media commonly used?

  To improve the visibility of blood vessels and the gastrointestinal tract.
• What are the types of contrast media based on the route of administration?

  1. Oral route CM: Barium sulfate, Gastrographin
  2. Iodinated IV CM: High osmolar (HCOM), low osmolar (LCOM)
  3. MRI agents: Gadolinium, Iron
  4. Ultrasound agents: Encapsulated lipid or albumin
• What is the primary use of iodinated contrast media?

  They are the main contrast agents for radiographic, fluoroscopic, angiographic, and CT imaging.
• What are some common iodinated contrast agents?

  Iohexol (Omnipaque), Niopam, Hexabrix, Urographin, Ultravist.
• How do low osmolar contrast media compare to high osmolar contrast media?

  Low osmolar contrast media are 5–10 times safer than high osmolar contrast media.
• What are the contraindications for using IV contrast media?

  1. History of previous reaction to contrast
  2. Renal failure
  3. Uncontrolled asthma (relative contraindication)
• What is the most serious adverse effect of IV contrast media?

  Anaphylactic reaction, an acute severe systemic hypersensitivity reaction.
• What symptoms are commonly associated with an anaphylactic reaction to IV contrast?

  Urticaria, angioedema, and bronchospasm.
• What should be assessed before administering iodinated contrast?

  • Previous contrast reaction
  • Asthma (must be stable)
  • Previous allergic reaction
  • Pregnancy and breastfeeding
• What defines contrast-induced nephropathy (CIN)?

  Impairment of renal function with specific urine output and serum creatinine changes.
• What are the urine output and serum creatinine criteria for CIN?

  Urine output $25 \, \mu moles/L$ within 48 hours and/or increase in serum creatinine >50% baseline within a week.
• When does serum creatinine concentration typically peak after contrast administration?

  Within the first 24 hours, reaching a peak by 2–3 days.
• What are the predisposing factors for nephrotoxicity?

  Elevated serum creatinine, diabetes mellitus, dehydration, age, large doses of contrast, and other nephrotoxic drugs.
• What are the types of vascular toxicity associated with contrast media?

  • Venous: Pain at injection site, pain extending up the arm, thrombophlebitis
  • Arterial: Vasodilatation, sensation of heat or pain
• What are the soft-tissue adverse effects of contrast media?

  • Pain, swelling, erythema from extravasated contrast medium
  • Treatment: Cold packs and limb elevation
  • Monitor for severe symptoms requiring surgical referral
• What are the contraindications for oral contrast media (Barium sulfate and Gastrographin)?

  1. Intra-peritoneal leak (recent surgery, bowel injury, perforated ulcer)
  2. Tracheo-esophageal fistula
• What is a potential complication of using Barium sulfate?

  Chemical peritonitis.
• What is a potential complication of using Gastrographin?

  Pulmonary edema.