Special procedures Flashcards
What are the osmolarity units?
mol/L
WHich contrast agents are ionic monomers? What is there iodine:particle radtio?
- Diatrizoate - Iothalamate - metrixoate - Ratio = 3:2
Which contrast agents are non-ionic monomers?
- Metrizamide - Iopamidol - Iopramide - Iohexal - Ratio= 3:1
Which contrast agent is an ionic dimer? What is the iodine:particle ratio?
Ioxaglate; 6:2 (3)
Which contrast agents are non-ionic dimers? Whatis there iodine:particle ratio?
Iotrolan and Iodixanol; 6:1 (6)
Which is more viscous, meglumine or salt?
meglumine
Rank the viscosity of the ionic monomers from greatest to least
Iothalmate>ditrizoate>metrizoate
Which has higher osmolality, sodium salts or meglumine?
Na salts
Rank the osmolality of the ionic monomers from greatest to least
Iothalmate>ditrizoate>metrizoate
What are some advantages of using nonionic monomers over ionic?
reduced tonicity, suitable for myelography, reduction in hypersensitivity reactions, increased image quality
How do the viscosity and osmolality of Hexabrix (ioxaglate) compare to the ionic monomers?
Significantly reduced osmolality, similar viscosity; the lower osmolality yields better image quality
COmpare the viscosity and osmolality of the non-ionic and ionic monomers
non-ionic monomer contrast is more viscous and less osmolar (more than 50% less) than ionic contrast
What is the importance of buffering agents in contrast media?
acidic - precipitation of radiopaque anion alkaline - instability of contrast with the release of free iodine and formation of cytotoxic aromatic amines
What is the effect of contrast on blood volume?
There is a decrease in blood volume, peaking 2 min post-contrast, due to hyperosmolarity. - water shifts from cells and extravascular space to plasma - diuresis induced by hyperosmolarity - renal excretion of contrast
How long after contrast administration will blood volume return to normal?
15-20 minutes post injection
As far as vascular effects, what are two examples caused by direct toxicity?
- echinocyte formation - decreased platelet aggregation and depression of coagulation factors
What pulmonary effects can hyperosmolality have?
- Pulmonary artery dilation (decr vascular resistance) - Hypervolemia (incr L atrial pressure and cardiac output) - Desiococyte formation (incr pulmonary capillary resistance) - Bezold-Jarish reflex (bradycardia, systemic hypotension) apnea followed by tachypnea)
What is the osmolality of Iopamidol (Isovue)?
616 mOsm/kg @ 300 mgI/mL
What is the osmolality of Iohexol (Omnipaque)?
709 (or 672) mOsm/kg @ 300 mgI/ml
What is the osmolality of Iopramide (Ultravist)?
(607) 500-700 mOsm/kg @ 300 mgI/kg
What is the osmolality of Iotrolan and Iodixanol?
300 mOsm/kg @ 300 mgI/mL
What is the normal barium GI transit time for dogs?
- GTT: 15-25 min
- GET: 1-4 hours (Thrall), up to 5-10 hours (Miyabashi)
- SITT: 90- 120 min (mean 73 min)
- SIET: 3-5 hours (mean 2.5 hours)
What is the barium GI transity time for cats?
- GTT: 15 min
- GET: 30 min
- SITT: <60 min
- SIET: <3 hours
