Special procedures (contrast studies)

Question 1

How much of an emergency is barium leakage?

What does it cause, what is mortality rate, etc

Answer 1

Barium leakage results in peritonitis/mediastinitis, fibrosis, granuloma formation.

50% mortality rate

Question 2

How much of an emergency is barium leakage?

What does it cause, what is mortality rate, etc

Answer 2

Barium leakage results in peritonitis/mediastinitis, fibrosis, granuloma formation.

50% mortality rate

Question 3

Describe two situations where administration of ORAL hypertonic iodinated contrast could be fatal?

Answer 3

1) Shocky patients - if administered orally - will pull fluid into the intestinal tract - further dehydrating them
2) Where aspiration may occur - esophagrams, bronchoesophageal fistulas –> pulmonary edema

Question 4

Describe two situations where administration of hypertonic iodinated contrast could be fatal?

Answer 4

1) Shocky patients - if administered orally - will pull fluid into the intestinal tract - further dehydrating them
2) Where aspiration may occur - esophagrams, bronchoesophageal fistulas –> pulmonary edema

Question 5

Metrizamide was one of the first non-iodinated contrast agents used - and was seen causing neurotoxic effects when used for myelography.Why did this occur?

Answer 5

2-deoxy-D-glucose side chain that inhibited glucose metabolism in the brain

Question 6

What are the two categories of iodinated contrast media?What characteristics separate these groups?

Answer 6

Ionic and non-ionic.

Ionic: When in solution - dissociates into the negative iodinated anion, and positively charged cation (sodium) Dissociation = greater osmoliaity (2-3x that of non-ionic)

Non-ionic - do not dissociate in solution

Question 7

What is range of osmolality of ionic contrast agents vs non-ionic media?

Answer 7

Ionic: 1900-2100mOsm/kg

Non-ionic: 290-900mOsm/kg (closer to blood)

Blood: 275-300mOsm/kg

Question 8

How frequently are contrast reactions seen in human patients, and what is that number related to?

Question 9

What are examples of idiosyncratic and non-idiosyncrati reactions?

Answer 9

Idiosyncratic - true allergic reaction - histamine release, complement cascade, immune-mediated, hypertonicity

Non-idiosyncratic:
acute renal failure - due to vasoconstriction, direct toxic effects on renal tubular cells
anti-coagulant effects - ionic agents have more anti-coagulant effects,
BBB damage - ionic agents increase BBB permeability, Bradycardia - vasovagal reaction
CHF - osmotic hypervolemia and worsen CHF
ECG changes - increased HR and prolonged QT interval
Endothelial lesions - increased permeability and thrombi formation,
Rigid erythrycotyes (difficulty moving through capillaries),
Decreased left ventricular function (after intracoronary injections),
Nausea/vomiting,
Peripheral vasodilation - agents have direct effect on endothelium - increasing their permeatility

Question 10

When should ionic agents NOT be used and why? (4 examples)

Answer 10

1) Dehydrated/renal disease patients - may result in acute renal failure
2) Intrathecal injection - seizures can be 1400x as toxic than IV injection
3) Anytime the BBB may be damaged - can result in increased intracranial pressure and decreased glucose uptake/metabolism (metrimazole)
4) CHF

Question 11

What are generic and brand names most commonly used for intrathecal injections?

Which has a higher LD50 for intrathecal injection?

Answer 11

Iohexol - Omnipaque
(stupid ass mnemonic - people who are omnipotent could put a hex on you)
LD50: 840mg I/kg

Iopamidol - Isovue
LD50: 1490mgI/kg

Question 12

Describe two situations where administration of hypertonic iodinated contrast could be fatal?

Answer 12

1) Shocky patients - if administered orally - will pull fluid into the intestinal tract - further dehydrating them
2) Where aspiration may occur - esophagrams, bronchoesophageal fistulas –> pulmonary edema

Question 13

Metrizamide was one of the first non-iodinated contrast agents used - and was seen causing neurotoxic effects when used for myelography.Why did this occur?

Answer 13

2-deoxy-D-glucose side chain that inhibited glucose metabolism in the brain

Question 14

What are the two categories of iodinated contrast media?What characteristics separate these groups?

Answer 14

Ionic and non-ionic.

Ionic: When in solution - dissociates into the negative iodinated anion, and positively charged cation (sodium) Dissociation = greater osmoliaity (2-3x that of non-ionic)

Non-ionic - do not dissociate in solution

Question 15

What is range of osmolality of ionic contrast agents vs non-ionic media?

Answer 15

Ionic: 1900-2100mOsm/kg

Non-ionic: 290-900mOsm/kg (closer to blood)

Blood: 275-300mOsm/kg

Question 16

How frequently are contrast reactions seen in human patients, and what is that number related to?

Question 17

What is the difference between idiosyncratic and non-idiosyncratic reactions?

Answer 17

Idiosyncratic - non-dose dependent

Non-idiosyncratic - dose dependent

Question 18

What are examples of idiosyncratic and non-idiosyncrati reactions?

Answer 18

Idiosyncratic - true allergic reaction

Non-idiosyncratic:
acute renal failure - due to vasoconstriction, direct toxic effects on renal tubular cells
anti-coagulant effects - ionic agents have more anti-coagulant effects,
BBB damage - ionic agents increase BBB permeability, Bradycardia - vasovagal reaction
CHF - osmotic hypervolemia and worsen CHF
ECG changes - increased HR and prolonged QT interval
Endothelial lesions - increased permeability and thrombi formation,
Rigid erythrycotyes (difficulty moving through capillaries),
Decreased left ventricular function (after intracoronary injections),
Nausea/vomiting,
Peripheral vasodilation - agents have direct effect on endothelium - increasing their permeatility

Question 19

When should ionic agents NOT be used and why? (4 examples)

Answer 19

1) Dehydrated/renal disease patients - may result in acute renal failure
2) Intrathecal injection - seizures can be 1400x as toxic than IV injection
3) Anytime the BBB may be damaged - can result in increased intracranial pressure and decreased glucose metabolism (metrimazole)
4) CHF

Question 20

What are generic and brand names most commonly used for intrathecal injections?

Answer 20

Iohexol - Omnipaque
(stupid ass mnemonic - people who are omnipotent could put a hex on you)
LD50 - 840mg I/kg
Iopamidol - Isovue
LD50: 1490 - mg I /kg

Question 21

What are brand names for Diatrizoate, and is it ionic or non-ionic

Answer 21

Ionic

Cystograffin, renograffin, gastrograffin

Question 22

How do you measure barium using weight-to-volume?

Give example

Answer 22

Certain amount of barium sulfate added to enough water to obtain predetermined total volume.

20% w/v suspension can be prepared by adding 20g of barium sulfate to water to = 100mL

20% w/v suspension can be prepared by adding 40g of barium sulfate to wter to =200mL

Question 23

How do you measure barium using weight-to-weight?

Give example

Answer 23

A certain weight of barium sulfate is added to enough water to obtain a total weight.

20% w/w solution can be prepared by adding 20g of barium sulfate to 80g (80mL) of water to obtain a final weight of 100 grams, and a volume slightly more than 80mL

Question 24

What is dose for a pneumocolon?

Answer 24

10cc/lb
30cc small dog
200-300 large dog

Question 25

What is dose for double contrast gastrogram? for dogs and cats

Answer 25

40kg - 1.5ml/kg cats - 6ml inflate with air - 20ml/kg

Question 26

Dose for upper GI with iodinated contrast for both cats and dogs?

Answer 26

Dogs - 700-875mg I/kg diluted to 10ml/kg | Cats - 600-800 mg I/kg diluted to 10ml/kg

Question 27

What is dose for upper GI with barium?

Answer 27

5-6cc/lb 10ml/kg increase kVP by 7-8

Question 28

What is dose for static esophagram with barium paste?

Answer 28

15ml per swallow in small dogs | 20-30mL per swallow in large dogs

Question 29

What is dose for esophagram with barium or ionic suspension?

Answer 29

5-15cc/lb

Question 30

What is dose for excretory urogram?

Answer 30

600-800mg I /kg

Question 31

What is dose for positive contrast cystogram?

Answer 31

5 cc /lb

Question 32

What is dose of double contrast cystogram?

Answer 32

Inject 3-5mL of 2% lidocaine 5-10cc of contrast distend with air (CO2 or NO2 preferred to room air) - 5ml/kg

Question 33

What is dose for celiogram?

Answer 33

350-400mg I /kg

Question 34

What is dose of contrast for a dynamic esophagram using barium in dogs vs cats

Answer 34

Dogs - 10ml | Cats - 5ml

Question 35

What is normal GI transit time for each portion of the tract in an upper GI study in dogs

Answer 35

``` Immediate - stomach 15 minutes - duodenal 1 hour - should reach colon 0.5-2 hours - stomach should be empty 0.5-2 hours post duodenal filling - complete small intestinal transit ```

Question 36

What is normal GI transit time for each portion of the tract in an upper GI study in cats

Answer 36

immediate - stomach 10m - duodenumal 30-60m - stomach empty 30-60m post duodenal filling - complete small intestinal transit

Question 37

What is transit time for iodinated contrast upper GI study in dogs?

Answer 37

Normal gastric emptying time - 30-120m | Small intestinal transit time - 60-90m

Question 38

What is transit time for iodinated contrast upper GI study in cats?

Answer 38

Normal gastric emptying time 30-90m | Small intestinal transit time 15-75m

Question 39

What is EU appearance of acute pyelonephritis?

Answer 39

pelvic dilation proximal ureteral dilation absent/incomplete filling of pelvic recesses

Question 40

What is EU appearance of chronic pyelonephritis

Answer 40

Pelvic dilation with irregular borders Proximal ureteral dilation Short blunted pelvic recesses

Question 41

What is EU appearance of hydronephrosis

Answer 41

pelvic dilation dilation of pelvic recesses uretera dilation

Question 42

What is EU appearance of renal parenchymal neoplasia?

Answer 42

distortion or deviation of renal pelvis +/- dilation. | Distorition or deviation or pelvic recesses

Question 43

What is EU appearance of renal pelvic neopalsia

Answer 43

Distorition or dilation of renal pelvis | Filling defects in renal pelvis

Question 44

What is dose for positive contrast urethrography?

Answer 44

cat - 5ml Small dog - 10ml medium dog -20ml large dog - 30ml

Question 45

what is the difference between idiosyncratic and non-idiosyncratic reactions to contrast media?

Answer 45

idiosyncratic - allergic reaction - non-dose dependent, will occur with test dose non-idiosyncratic - dose dependent - less likely to have reaction with a lower dose

Question 46

How much more soluble is CO2 and NO2 versus air?

Answer 46

CO2 - 20x more soluble than room air | NO2 - 40x more soluble than room air

Question 47

Describe the contrast utilized in CE-US Description of the use of CE-US in 4 dogs with pancreatic tumors. JSAP 55

Answer 47

Tiny gas filled microbubbles that are stabilized by outer shell that are injected into systemic circulation - traverse pulmonary capillary criculation and reach organ vascular supply. Once in the vascular supply, they remain at this level (unlike CT or MRI). Gas content is removed from blood by the lungs Stabilizing components removed by kidneys and liver. Microbubbles are detected following vibration and bursting - which increases SNR

Question 48

What are the 3 major phases of swallowing?

Answer 48

Oropharyngeal, esophageal, gastroesophageal

Question 49

What are hte 3 phases of the oropharyngeal phase of swallowing?

Answer 49

oral, pharyngeal, cricopharyngeal

Question 50

What abnormalities will you see with an oral dysphagia?

Answer 50

Bolus not formed bolus not propelled caudally to pharynx weak plungerlike activity of tongue (not pressing against dorsal aspect of the oral cavity) Subsequent stages are normal

Question 51

What abnormalities will you see with a pharyngeal dysphagia?

Answer 51

Normal oral stage Synchronous with cricopharyngeal opening Retention of contrast within the pharynx Inadequate pharyngeal contraction (high contraction ratio) (>0.6) Misdirection of the bolus into larynx or nasopharynx, or aspirated

Question 52

What abnormalities will you see with a cricopharyngeal dysphagia?

Answer 52

Depends on the form Chalasia (flaccidity) - Relaxation/incompetence of sphincter - large, air filled Prolonged time to cricopharyngeal sphincter opening Achalasia (failure to open - congenital) incomplete/lack of opening of the sphincter Vigorous attempsts to pass bolus Synchrony or dyssynchrony between pharyngeal contraction and opening

Question 53

What is the pharyngeal contraction ratio? How is it measured?

Answer 53

Measurement of the air within the pharynx during the most constricted phase of the pharynx (when dorsal pharyngeal wall is at its most ventral and caudal) of pixels of the pharynx at maximum contraction / # of pixels at time of relaxation (hold frame)

Question 54

What phases have abnormal pharyngeal contraction ratios?

Answer 54

Both pharyngeal and cricopharyngeal phases

Question 55

How do you differentiate between abnormalities of only pharyngeal and cricopharyngeal phases?

Answer 55

Both will have elevated contraction ratios Pharyngeal - normal opening of the UES Cricopharyngeal - delay of opening of hte UES

Question 56

How do you differentiate between abnormalities of only pharyngeal and cricopharyngeal phases?

Answer 56

Both will have elevated contraction ratios Pharyngeal - normal opening of the UES (0.07s) Cricopharyngeal - delay of opening of hte UES (0.28s)

Question 57

What is appropriate dose of contrast given to both cats and dogs for an esophagram?

Answer 57

Depends on agent Small-large breed dogs - 10-20mL if given barium suspension Cats - 5-7mL if suspension Paste - 10mL for dogs, 5mL for cats Iodine - 10-15ml for dogs, 5-10 for cats 50/50 contrast:water dilution