CEUS LI-RADS suggests alternative diagnostic imaging (i.e., CT or MRI) in ≤ 6 months if there is no observation on precontrast US. Can you explain the rationale?
The suggested management differs for CT/MRI LR-3 and CEUS LR-3. Why the difference?
What is the probability of HCC for each CEUS category?


FAQ-154: CEUS LI-RADS suggests alternative diagnostic imaging (i.e., CT or MRI) in ≤ 6 months if there is no observation on precontrast US. Can you explain the rationale?


One indication for CEUS is to assess LR-3, LR-4, and LR-M observations detected on prior CT or MRI. If CEUS is requested for this purpose but there is no observation on precontrast US, then LI-RADS recommends multiphase CT or MRI, rather than attempting CEUS. As mentioned on page 2, expert practitioners may attempt CEUS if there is no observation on precontrast US, but this is not currently recommended by CEUS LI-RADS. We anticipate that CEUS LI-RADS will be expanded to include assessment of precontrast occult nodules. If alternative imaging is pursued, interpreters should use their judgment in recommending the appropriate modality (CT or MRI), contrast agent (extracellular or hepatobiliary), and time interval. 


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FAQ-155: The suggested management differs for CT/MRI LR-3 and CEUS LR-3. Why the difference?

  

As explained in the CT/MRI manual, the suggested management for CT/MRI LR-3 is alternative or repeat diagnostic imaging in 3-6 months. By comparison, the suggested management for CEUS LR-3 is alternative or repeat diagnostic imaging in ≤ 6 months, with consideration for multidisciplinary discussion (MDD). The reason for emphasizing MDD for CEUS LR-3 is that the probability of HCC is thought to be greater for CEUS LR-3 than for CT/MRI LR-3: 

  • Two recent studies(1,2) showed that most LR-3 observations detected at CT or MRI are benign or indolent lesions that can be followed safely without requiring MDD in all cases. 

  • Less is known about the natural history of CEUS LR-3 observations, but preliminary evidence suggests that such observations warrant closer scrutiny. By definition, all CEUS observations are distinctive nodules in a cirrhotic liver visible on precontrast B-mode images, and thus have high probability of being HCC, unless contrast enhancement features are diagnostic of a benign entity such as a hemangioma. A recent retrospective study3 found that 60% (45/75) of CEUS LR-3 observations were HCC (see below). Therefore, MDD should be considered for all CEUS LR-3 observations with deliberation of reasonable diagnostic options, which may include alternative imaging in less than 3 months or biopsy. 


Reference List:

1. J-Y Choi et al. Indeterminate observations (Liver Imaging Reporting and Data System Category 3) on MRI in the cirrhotic liver: fate and clinical implications. AJR 2013. PMID 24147469

2. M Tanabe et al. Imaging outcomes of Liver Imaging Reporting and Data System Version 2014 Category 2, 3, and 4 observations detected at CT and MR Imaging. Radiology 2016. PMID 27115054

3. E Terzi, L. De Bonis, S. Leoni, et al. Dig Liv Dis, 2017; 49, Suppl 1, e22


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FAQ-156: What is the probability of HCC for each CEUS category?

  

In a retrospective study (1), Terzi et al. retrospectively reviewed a total of 350 consecutive CEUS-detected nodules in cirrhotic patients. Using CT/MRI (if appropriate) and/or nodule biopsy with histopathology evaluation as the reference, these authors reported the following probabilities associated with each CEUS category: CEUS LR-M: 6/15 (40%) HCC, 2/15 (13%) H-ChC, 7/15 (47%) ICC CEUS LR-5: 149/152 (98%) HCC, 1/152 (1%) H-ChC CEUS LR-4: 90/102 (88%) HCC CEUS LR-3: 45/75 (60%) HCC  


Reference List:

1. E Terzi, L. De Bonis, S. Leoni, et al. Dig Liv Dis, 2017; 49, Suppl 1, e22


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