From the Guidelines
The preferred type of CT scan to assess the liver, biliary tree, and pancreas is a contrast-enhanced abdominal CT with multiphasic imaging, including pancreatic, arterial, and portal venous phases, as recommended by the most recent guidelines 1. This approach is supported by the latest evidence, which emphasizes the importance of technical optimization, including the use of intravenous iodinated non-ionic contrast agent injection at 1.5 ml/kg and at a rate of 4-5 ml/s, to achieve high-quality images 1. The benefits of this approach include:
- Improved detection of tumors and metastases
- Better characterization of normal anatomy and pathological conditions
- Enhanced visualization of the biliary tree and pancreas
- Increased accuracy in staging and diagnosing pancreaticobiliary malignancies Key features of this imaging approach include:
- Non-contrast phase
- Arterial phase (25-35 seconds)
- Portal venous phase (70-90 seconds)
- Delayed phases (as needed)
- Thin-slice reconstructions (1-3mm)
- Oral contrast (as needed)
- CT cholangiography (as needed) It is essential to note that patients should fast for 4-6 hours before the examination, and adequate hydration is crucial both before and after the procedure to protect kidney function from the contrast material 1. The latest guidelines also recommend the use of standardized reporting templates to ensure that all relevant information is included in the imaging report, such as tumor characteristics, tumor-to-vessel contact, and the presence or absence of distant metastases 1.
From the FDA Drug Label
The pharmacokinetics of iohexol in both normal and abnormal tissue have been shown to be variable Contrast enhancement appears to be greatest immediately after bolus administration (15 seconds to 120 seconds). Thus, greatest enhancement may be detected by a series of consecutive two-to-three second scans performed within 30 to 90 seconds after injection (ie, dynamic computed tomographic imaging) Utilization of a continuous scanning technique (ie, dynamic CT scanning) may improve enhancement and diagnostic assessment of tumor and other lesions such as abscess, occasionally revealing unsuspected or more extensive disease Visualization of the joint spaces, uterus, fallopian tubes, peritoneal herniations, pancreatic and bile ducts, and bladder can be accomplished by direct injection of contrast medium into the region to be studied.
The type of Computed Tomography (CT) scan used to assess the liver, biliary tree, and pancreas is dynamic CT scanning. This involves a series of consecutive scans performed after the administration of a contrast agent, such as iohexol, to enhance the visualization of these organs and detect any lesions or abnormalities 2.
From the Research
Computed Tomography (CT) Scan for Liver, Biliary Tree, and Pancreas
- The type of CT scan used to assess the liver, biliary tree, and pancreas is a triple-phase or three-phase CT examination 3, 4.
- This type of CT scan involves multiple acquisitions, including an arterial phase, pancreatic phase, and portal venous phase, to evaluate the circulatory phases in the pancreatobiliary region 4.
- The scan protocol typically involves administering a contrast agent, such as iohexol, and using bolus-tracking techniques to optimize scan delays 3.
- The triple-phase CT examination allows for the acquisition of distinct circulatory phases, including the arterial, pancreatic, and portal venous phases, with 1-mm collimation 4.
- This type of CT scan is useful for assessing the liver, biliary tree, and pancreas, including the detection of lesions and the evaluation of tumor response after nonsurgical treatments 5, 6.