From the Guidelines
For a 10 cm solid right hepatic lobe mass detected on ultrasound, CT with contrast is the preferred next imaging study. This recommendation is based on the American College of Radiology (ACR) appropriateness criteria for suspected liver metastases, which suggests that multidetector helical CT (MDCT) is the preferred examination for initial assessment due to its ability to image the liver and potential sites of extrahepatic disease during the same examination 1.
Key Considerations for CT Imaging
- The efficacy of CT is heavily dependent on technique, with parameters such as kilovolt (peak) (kV[p]), milliamperes (mA), contrast delivery, and slice thickness being crucial for optimal imaging 1.
- Thinner reconstructed images (e.g., 2.5 mm) improve lesion detection and characterization compared to thicker images 1.
- Arterial-phase and portal venous phase (PVP) imaging, with a 3- to 5-mL/s injection rate and 2.5- to 5-mm slice thickness, are recommended for high sensitivity and specificity in liver lesion characterization 1.
Comparison with MRI
- While MRI offers superior contrast resolution and the ability to obtain diffusion-weighted imaging (DWI), CT is preferred for its speed and ability to image extrahepatic disease sites simultaneously 1.
- MRI may be considered in specific cases where its advantages are deemed beneficial, such as in patients with contraindications to CT contrast or when detailed soft tissue characterization is necessary 1.
Clinical Implications
- Regardless of the imaging modality chosen, a 10 cm solid liver mass requires prompt evaluation by a hepatologist or surgical oncologist due to its potential for malignancy and the need for timely management.
- The choice between CT and MRI should be made based on individual patient factors, including the need for detailed soft tissue characterization, potential contraindications to certain imaging modalities, and the clinical suspicion of specific diagnoses.
From the Research
Next Steps for Diagnosing a 10 cm Solid Right Hepatic Lobe Mass
- Given the initial diagnosis of a 10 cm solid right hepatic lobe mass on ultrasound, the next step would be to use either CT or MRI for further characterization, as both are commonly used for this purpose 2.
- A study comparing CT and MRI for the diagnosis of hepatocellular carcinoma in patients with liver cirrhosis found that MRI outperforms CT, especially for lesions between 1-1.9 cm 3.
- Another study found that CT and MRI improve detection of hepatocellular carcinoma compared to ultrasound alone in patients with cirrhosis, with MRI showing higher sensitivity 4.
- The diagnostic accuracy of CT for hepatocellular carcinoma in adults with chronic liver disease has been assessed, showing a sensitivity of 77.5% and specificity of 91.3% 5.
- A systematic review and meta-analysis found that MRI has a higher sensitivity than CT for the diagnosis of hepatocellular carcinoma in patients with cirrhosis, but the specificities and positive likelihood ratios were not significantly different 6.
Considerations for Choosing Between CT and MRI
- The choice between CT and MRI may depend on the specific characteristics of the lesion and the patient's condition, as well as the availability and expertise of the imaging modalities.
- MRI with gadoxetic acid may be particularly useful for detecting hepatocellular carcinoma, as it has been shown to outperform CT and extracellular contrast-enhanced MRI in some studies 3, 6.
- However, the evidence is not conclusive, and both CT and MRI can be useful for diagnosing hepatocellular carcinoma, with the choice depending on individual patient factors and institutional preferences 2, 5, 6.