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Page 8 of 16 Brunsing et al. Hepatoma Res 2020;6:59 I http://dx.doi.org/10.20517/2394-5079.2020.50

Figure 4. Positive dynamic-AMRI examination: 80-year-old male with HCV cirrhosis, images show a 11 mm observation in segment 7.
The lesion has major features of HCC including nonrim APHE, washout and enhancing capsule (arrows) indicating definite HCC (LI-
RADS-5). AMRI: abbreviated magnetic resonance imaging; HCV: hepatitis C virus; HCC: hepatocellular carcinoma; LI-RADS: Liver
Imaging Reporting and Data System; APHE: arterial phase hyperenhancement

Advantages
Dynamic-AMRI offers unique advantages. The defining imaging features of HCC (i.e., the LI-RADS major
features of size, APHE, washout appearance, and enhancing capsule appearance) are determined from
dynamic imaging. When a liver observation meets the required diagnostic criteria, dynamic AMRI alone
suffices for definitive diagnosis of HCC per LI-RADS (i.e., LR-5). It also permits the diagnosis of tumor
in vein (TIV). Additionally, it provides cost benefits, as the contrast agents used in dynamic AMRI are
[52]
typically less expensive than the contrast agent (gadoxetate disodium) required for HBP-AMRI . Some
investigators have used coronal T2 imaging for localizer sequences, which can aid in characterizing benign
lesions such as simple cysts and hemangiomas.

Disadvantages
The disadvantages of dynamic-AMRI relate to the lack of additional non-contrast sequences, which may
[53]
provide ancillary imaging features otherwise not available from the dynamic images . The inability of
dynamic-AMRI to evaluate these features may cause miscategorization of observations. In particular,
dynamic-AMRI might over-categorize some vascular pseudolesions (e.g., arterio-portal shunts) as
indeterminate (LR-3), potentially leading to unnecessarily close follow up. In theory, dynamic-AMRI
also might under-categorize some early or small HCCs as LR-3, potentially delaying diagnosis, but the
frequency with which this occurs is thought to be low. HCC detection by dynamic-AMRI depends on the
timing and quality of arterial-phase imaging, which cannot be repeated if these images are mistimed or
degraded by motion artifact or other problems. Finally, dynamic-AMRI requires a power injector for bolus
intravenous administration of GBCA, which may not be available at all facilities and introduces complexity.

Studies to date
A few studies to date have retrospectively assessed the performance of a simulated dynamic-AMRI (derived
by extracting only the dynamic sequences from a complete MRI) for HCC detection in patients with
cirrhosis [Table 2]. These studies have shown that dynamic AMRI is diagnostically similar to complete MRI
for HCC detection [26,27] , with per-patient reported sensitivity and specificity of 94% and 88%, respectively .
[26]
However, these studies were conducted in diagnostic cohorts, in whom complete MRIs were indicated for
known or clinically suspected liver lesions, which may have caused inflation in the sensitivity estimates.
Dynamic-AMRI has yet to be tested prospectively in an HCC surveillance population.

Summary Statement
Dynamic-AMRI can characterize the defining imaging features of HCC and allows the detection and
diagnosis of HCCs in a single surveillance exam. The absence of T2 weighted and DWI sequences, however,
may cause diagnostic uncertainty, particularly for benign vascular pseudolesions, and lead to unnecessary