From the Guidelines
A HIDA scan is considered a reasonable option for diagnosing acute cholecystitis, particularly when CT is equivocal, due to its status as the gold standard for this condition, despite requiring a patient to fast for several hours beforehand. According to the 2024 clinical practice guideline update by the Infectious Diseases Society of America 1, HIDA scans are a viable choice for subsequent imaging studies beyond CT, especially when acute cholecystitis is suspected. The benefits of HIDA scans include their ability to provide a definitive diagnosis of acute cholecystitis, as well as being less costly than alternative imaging modalities like MRI/MRCP. However, it's essential to consider the need for patients to fast before undergoing a HIDA scan, which may be a drawback in certain clinical scenarios.
Some key points to consider when deciding to use a HIDA scan include:
- The patient's ability to fast for several hours before the test
- The potential benefits of HIDA scans in providing a definitive diagnosis of acute cholecystitis
- The comparison with other imaging modalities, such as MRI/MRCP, which may offer faster results and clearer pictures of surrounding structures, but are more expensive
- The consideration of radiation exposure, particularly in children, when choosing between different imaging modalities, as outlined in the 2024 guideline update 1.
In terms of clinical practice, HIDA scans can be a valuable tool in the diagnosis of acute cholecystitis, especially in cases where other imaging modalities are equivocal or inconclusive. As stated in the guideline update 1, HIDA scans are considered the gold standard for diagnosing acute cholecystitis, making them a reasonable choice for clinicians when trying to confirm this diagnosis.
From the Research
Hida Scan Overview
- A Hida scan, also known as a hepatobiliary scan, is a nuclear medicine test that uses a small amount of radioactive material to evaluate the function and structure of the gallbladder and bile ducts 2.
- The scan involves injecting a radioactive tracer, such as 99mTc-HIDA, into the bloodstream, which is then taken up by the liver and excreted into the bile ducts and gallbladder 2.
Clinical Applications
- Hida scans can be used to diagnose various hepatobiliary diseases, including acute and chronic cholecystitis, and to assess biliary drainage in patients with jaundice 2.
- The scan can also help identify obstruction of the cystic duct or common bile duct, and can be used to evaluate the function of the gallbladder and bile ducts in patients with surgically altered biliary tract anatomy 2.
Utilization and Overuse
- Despite the availability of clinical guidelines for diagnosing acute cholecystitis, Hida scans are often overutilized, particularly in patients who meet clinical criteria for cholecystitis based on the Tokyo guidelines 3.
- A study found that over half of patients who met the Tokyo guidelines for suspected or definite cholecystitis underwent a Hida scan, indicating overutilization 3.
- The overuse of Hida scans can increase healthcare costs and delay care, and it is recommended that these scans be reserved for cases with inconclusive ultrasound results but high clinical suspicion for cholecystitis 3.