1. Purpose of this exam is to evaluate hepatobiliary flow through the liver
1. Hepatocytes pick up the radiopharmaceutical
2. Bile flows through the hepatic ducts
3. To the cystic duct and into the gall bladder
4. Bile flows out of the gall bladder into the common bile duct and finally into the duodenum


2. The following is a diagram of the hepatobiliary tree

Right Hepatic Duct (RHD) Left Hepatic Duct (LHD) Common Hepatic Duct (CHD) Cystic Duct (CD) Gallbladder (GB) Common Bile Duct (CBD) Sphincter of Oddi (SOO) Duodenum (D) Falciform Ligament (FL)

3. Hepatobiliary Agents - all radiopharmaceuticals will be identified as ^99mTcIDA. Forming different N substitutions on the carbon ring results in various forms of IDA (Iminodiacetic acid). There are suggested radiopharmaceuticals for this analysis
1. ^99mTc DISIDA (Disofenin) (Hepatolite)
1. Example of a package insert
2. In normal functioning liver 88% of this agent is excreted by the hepatic system with 10% by the kidneys
3. Acceptable visualization of hepatic function can be assessed with bilirubin levels of up to 20 mg/dL
2. ^99mTc BROMIDA (Mebrofenin) (Choletec)
1. Has the greatest hepatic uptake at ~98%
2. Least affected by high levels of bilirubin
3. General comments on IDA physiology
1. Once injected, IDA binds to plasma protein, which reduces renal excretion
2. IDA competes with bilirubin at the same sites of extraction on the hepatocyte, this type of competition is known as competitive inhibition
3. The greater the level of bilirubin, the less the uptake of IDA and the greater the renal excretion
4. The hepatocytes extract IDA and bilirubin via active transport


4. A look at the diseases
1. Points that constitutes a normal scan
1. Normal bile flow throughout the hepatic system
2. Gall bladder fills with activity
3. Activity dumps into the small intestine
4. All of this occurs within the hour
2. Acute cholecystitis
1. Gall stone blocking the cystic duct
2. Gall bladder does not image
3. Small intestine visualizes
3. Chronic cholecystitis
1. Temporary blockage of the cystic duct
2. Gall bladder appears after the 1-hour injection
3. Small intestine is visualized
4. Acalculous cholecystitis (vs. calculous)
1. Reduced function of GB without stones
2. Slug/inflammation of the gall bladder
3. The gallbladder usually fills, but there is a reduction in the injection fraction when kinevac/sincalide (synthetic form of CCK) is administered
4. More data on kinevac can be found at: https://www.wellrx.com/kinevac/monographs/
5. Dumping of the small intestine should be seen
5. Hepatobiliary Procedure (HIDA)
   1. Setup
      1. 6 - 8 mCi of IDA
      2. LEHR collimator
      3. 256 x 256 matrix
      4. Following IV administration
   2. Static acquisition
   1. 750k per image
   2. Acquire every 5 minutes
   3. Image for at least 60 minutes
   3. Dynamic acquisition (alternative)
      1. Take 1-minute images dynamically
      2. Collect data for 60 minutes
   4. The study is complete when
      1. Gal bladder visualizes
      2. Activity is seen in the small bowel
         
6. Pharmacological intervention
   1. Morphine augmentation (not done in the Richmond area)
      1. Administered when there is dumping of the tracer into the small bowel, but no activity is seen in the GB
      2. After one hour consider injecting morphine
      3. Without morphine delay images may take up to 4 hours - you need to wait for all the activity to leave the GB
      4. If activity is not seen in the GB after 1 hour, administer 0.04 mg/kg morphine IV for 2 to 3 minutes
      5. Causes constriction of the Sphincter of Oddi resulting in pressure building up within the CBD
      6. Continue imaging every 5 minutes for up to 30 minutes
      7. If GB does not visualize, then acute cholecystitis is diagnosed
      8. Kinevac should not be administered immediately following morphine augmentation
      9. If kinevac is used pre-post morphine, a 30 minute delay is suggested
   2. CCK derivative (Kinevac )
      1. Should be administered if the patient hasn't eaten for more than 24 hours
         1. Reason - GB stasis
      2. Kinevac dose = 0.02 μg/kg of body weight
      3. Dose patient 30 minutes before IDA injection
      4. Causes contractility of GB reducing a false positive study
   3. Determination of GB ejection fraction to rule out Acalculous cholecystitis

1. Determine when the GB is at maximum filling ~1 hour post IDA injection
2. Inject Kinevac IV over a 3-minute period or up to 60 minutes. This depends on department protocol
3. Kinevac dose = 0.02 ug/gm of body weight
4. Some clinics will give a 3-minute kinevac administration and then image 20 to 30 minutes or longer. Can be static or dynamic
5. Some clinics will administer kinevac for up to 1 hour and take dynamic images - one frame per minute
6. Draw an ROI over the PreCCK image of the GB
7. Draw an ROI over every other GB image after the CCK was administered
8. Plugin the numbers to the above formula to determine %EF of the GB
9. Example

Case Studies

Case 1 The first case you've seen before. It is an animated gif showing bile moving through the hepatobiliary system. In these images you should be able to identify the GB and small intestine, all of which imaged within 60 minutes after the patient was injected (this is considered normal). However, there is an abnormal accumulation of activity seen just below the left lobe of the liver. This abnormal accumulation of activity is known as bile reflux.

Case 2

Question: From a technical standpoint, what type of augmentation might you suggest that would reduce the amount of imaging time with this patient?