Acvr - Nuke Med. - Tc-99M-Ida

Front 1

What is Tc-99m-IDA and name one of its derivatives?

Back 1

iminodiacetic acid (IDA)

Mebrofenin

Front 2

List several indication of its use (IDA).

Back 2

1. hepatobiliary scintigraphy

2. trans-splenic PSS

3. solid-phase gastric emptying

Front 3

The liver receives ____% of its blood supply from the portal venous system and ____% from the hepatic arteries.

Back 3

70% from portal

30% from hepatic arteries

Front 4

Hepatobiliary agents are analogues of what?

Back 4

Lidocaine

Front 5

What is the percentage of first pass extraction of lidocaine by the liver?

Back 5

> 90%

Front 6

IDA is loosely bound to albumin which accomplishes what?

Back 6

increased hepatic uptake

and

decreases renal excretion

Front 7

What is IDA's mechanism of location?

Back 7

active transport on the hepatocyte membrane via a bilirubin anion receptor

Front 8

List 5 specific indications for hepatobiliary scintigraphy.

Back 8

1. function

2. morphology

3. patency

4. diff. btwn. intra vs. extrahepatic obstruction

5. biliary disease

Front 9

What acquisition and positioning are advised for hepatobiliary scintig.?

Back 9

Frame mode - dynamic

right lateral

Front 10

When should IDA be given and at what point can hepatic morphology be evaluated (time of peak uptake)?

Back 10

give simultaneously with injection

morphology seen best at 6-8 minutes

Front 11

In a normal patient, what percentage of IDA goes to the hepatocytes (normal extraction), and what percentage remains in the vascular space, ultimately reaching the heart?

Back 11

95% to liver

5% to heart

Front 12

In a normal patient, after what time period should one be unable to see activity outside of the liver?

Back 12

> 5 minutes

Front 13

What is the normal half-life for hepatic excretion?

Back 13

19 minutes

Front 14

List 4 causes of a prolonged hepatic excretion half-life.

Back 14

1. cholestasis

2. cholangiohepatitis

3. chronic extrahepatic obstruction

4. hepatic parenchymal disease (hepatocellular)

Front 15

In an abnormal dog, what percentage of IDA enters the hepatocytes, what percentage remains in the vascular space (and goes to the heart), and how is liver activity affected on the curve?

Back 15

a. 50% to liver

b. 50% to heart

c. sharp decline in activity (then slow decline)

Front 16

When should GB and small intestinal activity be seen in the normal patient?

Back 16

< 1 hour

Front 17

What drug can be administered in order to evaluate GB ejection fraction and emptying rate?

Back 17

CCK

Front 18

a. What is the normal GB ejection fraction?

b. What is the normal GB emptying rate?

Back 18

a. 40 - 80%

b. 10% per minute

Front 19

In the case of a biliary obstruction, what subsequently elevated substance competes with IDA uptake, resulting in reduced IDA uptake and HEF?

Back 19

bilirubin

Front 20

What effect to opioids have upon IDA transit to the intestine?

Back 20

prolonged transit

(constriction of sphincter of Oddi)

Front 21

What effect will acute cholecystitis (without obstruction) have upon HEF, liver excretion, and biliary clearance respectively?

Back 21

none, none, and none

Front 22

What effect will chronic cholecystitis have upon HEF and liver excretion, respectively?

Back 22

reduced HEF

and

prolonged liver excretion

Front 23

What effect will chronic cholecystitis have upon GB clearance?

Back 23

prolonged

(GB unseen at < 1 hour, but seen by 4 hours)

Front 24

What effect will extrahepatic cholestasis have upon HEF and hepatic excretion respectively?

Back 24

normal HEF

prolonged hepatic excretion

Front 25

With what hepatobiliary disease process do the GB and SI appear as a virtually permanent void/photopenic region?

Back 25

extrahepatic cholestasis

Front 26

What are the two most important criteria for diagnosing a partial obstruction of the biliary tract?

Back 26

1. Very delayed identification of intestinal activity (~18 hours).

2. Decreased volume of intestinal activity.

Front 27

What is a common appearance of the gallbladder in case of partial and complete obstructions?

Back 27

a large and photopenic void

Front 28

In cases where there is complete non-visualization of the small intestine, what disease process would be expected?

Back 28

chronic extrahepatic obstruction

Front 29

With regard to trans-splenic portal scintigraphy, what is one reason one might select Mebrofenin over pertechnetate.

Back 29

Mebrofenin has a higher first-pass extraction by the liver.

Front 30

What radionuclide is commonly used for solid-phase gastric emptying studies?

Back 30

Tc-99m - Mebrofenin

(it has a > 90% solid-phase retention and stability - just add to wet or dry food)

Front 31

How long should patients be fasted for a solid-phase study?

Back 31

12 - 18 hours

Front 32

What acquisition mode and positioning are advised for solid-phase studies?

Back 32

Frame mode - static

right and left lateral abdomen

Front 33

Define titurition.

Back 33

mixing without emptying

Front 34

Gastric emptying of the solid-phase is dependent on what 3 factors?

Back 34

1. The amount fed (Kcal/Kg body weight)

2. The amount of water concurrently consumed

3. The diet form (canned vs. kibble)

Front 35

List the 3 phases of normal, solid-phase, gastric emptying.

Back 35

1. Initial Lag Phase (titurition/mixing)

2. Linear Phase (initial emptying)

3. Delayed Phase (fiber gastric emptying)