Is a CT (Computed Tomography) abdominal triphase the initial imaging approach for suspected hepatocellular carcinoma, hemangiomas, focal nodular hyperplasia, hepatic adenomas, cysts, abscesses, or cirrhosis?

From the Guidelines

A CT abdominal triphase is indeed the initial imaging approach for suspected hepatocellular carcinoma (HCC) and is valuable for evaluating other focal liver lesions such as hemangiomas, focal nodular hyperplasia (FNH), hepatic adenomas, cysts, abscesses, and cirrhosis. This recommendation is based on the most recent and highest quality study available, which emphasizes the importance of multiphasic imaging in the diagnosis and characterization of liver lesions 1.

Key Points to Consider

• The CT triphase protocol involves imaging the liver during three distinct phases of contrast enhancement: the arterial phase, portal venous phase, and delayed phase, each providing unique information about liver lesions based on their blood supply and enhancement patterns.
• HCC typically shows enhancement during the arterial phase and washout during later phases, while hemangiomas demonstrate peripheral nodular enhancement with progressive central filling, and FNH often shows rapid arterial enhancement with a central scar.
• The triphase protocol is particularly important in cirrhotic patients where early detection of HCC is critical, as it allows for the characterization of most liver lesions based on their enhancement patterns.
• While ultrasound may serve as a screening tool and MRI offers superior soft tissue contrast in some cases, the CT triphase remains the standard initial comprehensive evaluation due to its widespread availability, speed, and ability to characterize most liver lesions based on their enhancement patterns.

Clinical Application

In clinical practice, the use of CT abdominal triphase is guided by evidence-based recommendations that prioritize the detection and characterization of liver lesions, particularly in high-risk populations such as those with cirrhosis 1. The choice between CT and MRI for the evaluation of liver lesions depends on various factors, including the specific clinical scenario, the availability of resources, and the patient's individual characteristics, with CT being preferred for its speed and widespread availability, and MRI being preferred for its superior soft tissue contrast and lack of ionizing radiation 1.

Evidence-Based Practice

The evidence supporting the use of CT abdominal triphase for the evaluation of liver lesions is based on a comprehensive review of the literature, including studies that have evaluated the diagnostic accuracy and clinical utility of different imaging modalities in the detection and characterization of liver lesions 1. The recommendation to use CT abdominal triphase as the initial imaging approach for suspected HCC and other focal liver lesions is based on the highest quality evidence available, which emphasizes the importance of multiphasic imaging in the diagnosis and characterization of liver lesions.

From the Research

Imaging Approach for Suspected Hepatocellular Carcinoma and Other Liver Pathologies

• For suspected hepatocellular carcinoma, hemangiomas, focal nodular hyperplasia, hepatic adenomas, cysts, abscesses, or cirrhosis, a CT abdominal triphase may be considered as an initial imaging approach 2, 3, 4, 5, 6.
• The use of dynamic multiphase contrast-enhanced CT or MRI is the current standard for imaging diagnosis of hepatocellular carcinoma 3.
• CT and MRI play critical roles in the diagnosis and staging of hepatocellular carcinoma, and state-of-the-art imaging techniques with extracellular and hepatobiliary contrast agents are essential 4.
• For focal nodular hyperplasia, imaging plays a key role in the diagnostic pathway, and misdiagnosis may have a major clinical effect, making CT, MRI, and ultrasound important tools for diagnosis 5.
• Dual-phase helical CT has been shown to be valuable in the pretransplantation diagnosis and staging of hepatocellular carcinoma in patients with cirrhosis, with a sensitivity of 78.8% and a positive predictive value of 88% 6.

Specific Pathologies and Imaging Approaches

• Hepatocellular carcinoma: CT, MRI, and contrast-enhanced US have replaced biopsy for diagnosis, with dynamic multiphase contrast-enhanced CT or MRI being the standard 3.
• Hemangiomas: may be detected using CT, MRI, or ultrasound, but may also be false-positive findings on CT 6.
• Focal nodular hyperplasia: typical radiological features on CT, MRI, and ultrasound allow for a specific noninvasive diagnosis 5.
• Hepatic adenomas: imaging plays a key role in diagnosis, but may be challenging to differentiate from other lesions 5.
• Cysts, abscesses, and cirrhosis: CT and MRI can be used to detect and characterize these lesions, with CT being useful for detecting complications such as abscesses 2.