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Brunsing et al. Hepatoma Res 2020;6:59 I http://dx.doi.org/10.20517/2394-5079.2020.50 Page 11 of 16

apply HBP-AMRI need to be aware of this potential pitfall and understand that HBP-AMRI will detect
some patients with HCC precursor nodules prior to overt malignant transformation. Conversely, some
reports have shown that occasionally HCCs can be iso- or hyperintense on HBP imaging and may be
mistaken for benign lesions [15,23,40] .

Studies to date
Three studies have retrospectively assessed the performance of a simulated HBP-AMRI (derived from a
complete MRI with gadoxetate) for HCC detection in patients with cirrhosis or chronic hepatitis B [Table 2],
[28]
the largest of which was a dual center study in a surveillance population . These studies have reported per-
patient sensitivities in the range of 80%-83%, per-patient specificities in the range of 93%-96%, and a per-
lesion sensitivity of 85%. One study evaluated the performance of HBP-AMRI interpreted prospectively in
[31]
an HCC surveillance population, demonstrating a sensitivity of 91% and sensitivity of 99% . In this study,
20% of patients had Child Pugh B or C cirrhosis with 12 HCC in the cohort. To our knowledge, this study
[34]
and the previously discussed study evaluating DWI alone are the only two studies to date evaluating the
[58]
performance of AMRI interpreted prospectively in the clinical setting. Clinical trials are underway .

The financial implications of HBP-AMRI have also been studied. By one estimate, HBP-AMRI screening
[29]
would result in a 30% immediate cost savings relative to complete contrast enhanced-MRI . In another
estimate, an HCC screening strategy using HBP-AMRI had a favorable incremental cost-effectiveness ratio
(ICER) ($3,000) per quality-adjusted life year (QALY) gained compared to US, across a wide range of HCC
[59]
incidences .

Summary statement
HBP-AMRI, perhaps the most well studied of the AMRI approaches, offers a streamlined workflow with
simple, established reporting guidelines, the use of high-contrast sequences that can be repeated if needed,
and preliminary studies demonstrating its cost effectiveness and diagnostic performance in surveillance
populations. The disadvantages are the potential for reduced accuracy in some patients with advanced
cirrhosis, the increased cost of the GBCA used for HBP-AMRI compared to dynamic-AMRI, and the
possibility of detecting very early HCCs that cannot be confirmed with currently available diagnostic
imaging tests.

CURRENT ISSUES AND GAPS IN KNOWLEDGE
Despite the growing body of literature suggesting AMRI offers superior sensitivity in HCC detection to
that reported for surveillance US, there is insufficient evidence to recommend widespread adoption of
AMRI by international guidelines. Prospective studies evaluating the performance and cost-effectiveness
of AMRI versus US in surveillance populations for detecting HCC and prolonging life will be needed to
inform changes to existing guidelines. Although it may take years for that evidence to be generated, AMRI
can be of use today. One potential way to integrate AMRI into current practice is to apply it in patients who
have severe limitations of their US examinations, such as those with an US LI-RADS visualization score
[54]
of C , or at the discretion of hepatologists, who might be concerned about the reliability of US imaging
for patients with markedly heterogeneous liver parenchyma due to underlying cirrhosis or with poor liver
visualization due to large body habitus, ascites, or other factors.

Another challenge of implementing AMRI, at least in the United States, is insurance reimbursement.
The overarching goal of AMRI is to leverage the high sensitivity of MRI in a cost-effective manner.
Moreover, one of the key elements in evaluating or implementing a surveillance program is the overall
cost effectiveness of the approach. However, in order to accurately assess the cost-effectiveness of AMRI
there must be a billing mechanism that appropriately reflects the reduced scanner time and other health-
economic benefits of the shortened protocols. This mechanism currently does not exist in the United States.