Nuclear Medicine: HIDA Scans for the ABR Core Exam Part 2
Part 2 question and answer review of hepatobiliary scintigraphy for ABR Core Exam review. Check out the free downloadable study guide for this and other radiology board review topics at www.theradiologyreview.com.
Can you perform a HIDA scan for acute cholecystitis on a patient who is already on morphine? If so, how will the presence of morphine affect your imaging?
Yes, you can scan if a patient is already on morphine. This does not limit the ability to see gallbladder filling to evaluate for acute cholecystitis. Due to increased sphincter of oddi constriction this may delay transit of tracer into the bowel. Therefore, some say you should wait 4 hours for the morphine to wear off, but this is optional.
What are some patient contraindications to give morphine for a HIDA scan?
Increased intracranial pressure in children, severe respiratory depression in a nonventilated patient, allergy to morphine are absolute contraindications. Acute pancreatitis is a relative contraindication as increasing the sphincter of oddi pressure can make the pancreatitis worse.
What does it mean if you have prompt hepatic uptake with delayed excretion into the biliary system? What can cause this?
This means there is no hepatic dysfunction so this is less likely to be due to acute common bile duct obstruction as that does cause some hepatic dysfunction which would manifest with delayed hepatic uptake and delayed biliary secretion. Potential causes of prompt hepatic uptake but delayed biliary excretion are medications to include Dilantin and oral contraceptives.
If sincalide is unavailable, what else can you do to get the gallbladder to contract for ejection fraction calculation?
Give the patient a fatty meal to stimulate gallbladder contraction, then image.
What is a potential indication for hepatobiliary scintigraphy in a newborn?
Evaluation of biliary atresia versus neonatal hepatitis
How do you distinguish between biliary atresia and neonatal hepatitis on a HIDA scan?
If you see transit of radiotracer into the bowel this is neonatal hepatitis because you must have a biliary system to see transit to the bowel. Biliary atresia will not show bowel activity.
How long do you wait to see bowel activity before you consider the possibility that biliary atresia is present?
AT LEAST 24 hours.
If you don’t see bowel activity at 24 hours what is the next step?
Give phenobarbital to supercharge the hepatocytes’ ability to uptake and excrete the radiotracer and repeat the study. If you still don’t see bowel activity after 24 hours, then this supports biliary atresia.
What is the name of the surgical procedure used to correct neonatal biliary atresia?
Kasai procedure. You have better outcomes when the Kasai procedure is performed earlier versus later so prompt diagnosis of biliary atresia is important.
What is an indication to perform a HIDA scan in a patient who has had a cholecystectomy?
Evaluation of bile leak. You inject, watch tracer uptake and transit through the liver into the biliary tree and look in the gallbladder fossa, right paracolic gutter, and pelvis for activity to show the bile leak.
What is the reappearing liver sign and what does this sign mean?
The reappearing liver happens when leaked radiotracer from a bile leak tracks superiorly into the perihepatic space and coats along the surface of the liver giving the appearance that the liver is reappearing instead of washing out like normal. You see an initial decrease in liver activity, followed by a paradoxical increase in activity which is due to tracer AROUND the liver instead of tracer within the liver. This confirms a bile leak.
Focal liver uptake on a HIDA scan is most indicative of which liver lesion?
Focal nodular hyperplasia. Uptake in a liver lesion should make you think of focal nodular hyperplasia for board examinations. This is often most evident on washout images of the liver.
