Special procedures

Question 1

What are the osmolarity units?

Answer 1

mol/L

Question 2

WHich contrast agents are ionic monomers? What is there iodine:particle radtio?

Answer 2

• Diatrizoate - Iothalamate - metrixoate - Ratio = 3:2

Question 3

Which contrast agents are non-ionic monomers?

Answer 3

• Metrizamide - Iopamidol - Iopramide - Iohexal - Ratio= 3:1

Question 4

Which contrast agent is an ionic dimer? What is the iodine:particle ratio?

Answer 4

Ioxaglate; 6:2 (3)

Question 5

Which contrast agents are non-ionic dimers? Whatis there iodine:particle ratio?

Answer 5

Iotrolan and Iodixanol; 6:1 (6)

Question 6

Which is more viscous, meglumine or salt?

Answer 6

meglumine

Question 7

Rank the viscosity of the ionic monomers from greatest to least

Answer 7

Iothalmate>ditrizoate>metrizoate

Question 8

Which has higher osmolality, sodium salts or meglumine?

Answer 8

Na salts

Question 9

Rank the osmolality of the ionic monomers from greatest to least

Answer 9

Iothalmate>ditrizoate>metrizoate

Question 10

What are some advantages of using nonionic monomers over ionic?

Answer 10

reduced tonicity, suitable for myelography, reduction in hypersensitivity reactions, increased image quality

Question 11

How do the viscosity and osmolality of Hexabrix (ioxaglate) compare to the ionic monomers?

Answer 11

Significantly reduced osmolality, similar viscosity; the lower osmolality yields better image quality

Question 12

COmpare the viscosity and osmolality of the non-ionic and ionic monomers

Answer 12

non-ionic monomer contrast is more viscous and less osmolar (more than 50% less) than ionic contrast

Question 13

What is the importance of buffering agents in contrast media?

Answer 13

acidic - precipitation of radiopaque anion alkaline - instability of contrast with the release of free iodine and formation of cytotoxic aromatic amines

Question 14

What is the effect of contrast on blood volume?

Answer 14

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

Question 15

How long after contrast administration will blood volume return to normal?

Answer 15

15-20 minutes post injection

Question 16

As far as vascular effects, what are two examples caused by direct toxicity?

Answer 16

• echinocyte formation - decreased platelet aggregation and depression of coagulation factors

Question 17

What pulmonary effects can hyperosmolality have?

Answer 17

• 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)

Question 18

What is the osmolality of Iopamidol (Isovue)?

Answer 18

616 mOsm/kg @ 300 mgI/mL

Question 19

What is the osmolality of Iohexol (Omnipaque)?

Answer 19

709 (or 672) mOsm/kg @ 300 mgI/ml

Question 20

What is the osmolality of Iopramide (Ultravist)?

Answer 20

(607) 500-700 mOsm/kg @ 300 mgI/kg

Question 21

What is the osmolality of Iotrolan and Iodixanol?

Answer 21

300 mOsm/kg @ 300 mgI/mL

Question 22

What is the normal barium GI transit time for dogs?

Answer 22

• 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)

Question 23

What is the barium GI transity time for cats?

Answer 23

• GTT: 15 min
• GET: 30 min
• SITT: <60 min
• SIET: <3 hours