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Brunsing et al. Hepatoma Res 2020;6:59 I http://dx.doi.org/10.20517/2394-5079.2020.50 Page 5 of 16

A B C

Figure 3. Positive NC-AMRI examinations: 66-year-old male with HCV cirrhosis. Images show a 14 mm observation in seen in the right
lobe. While subtle on T2WI (A) and T1WI (B, C), the presence of restricted diffusion (arrow) favors malignancy. HCV: hepatitis C virus;
NC AMRI: non-contrast abbreviated magnetic resonance imaging

Reporting
NC-AMRI exams can be interpreted as positive in the setting of a focal observation meeting any of the
above described criteria [Figure 3]. A positive examination would warrant a call back diagnostic study to
provide a definitive diagnosis of HCC. Features that suggest non-HCC malignancy do not affect the need
for call-back but might guide the radiologist’s choice of modality and contrast agent.

Advantages
NC-AMRI offers several advantages. By avoiding gadolinium-based contrast agent (GBCA) administration,
this approach curtails costs, avoids IV placement, saves time, and simplifies workflow. There is no need for
image acquisition timing, and images compromised by respiratory or other motion artefacts can simply
be repeated. It also eliminates any GBCA-associated risks, including rare but potentially serious adverse
[31]
reactions , theoretical concerns about gadolinium deposition in the brain [44,45] , and the remote possibility
of nephrogenic systemic sclerosis, a disorder unique to patients with acute kidney injury or severely
[46]
compromised renal function receiving high doses of certain GBCAs .

Disadvantages
The main disadvantage of NC-AMRI is that it relies exclusively on unenhanced images, which tend to have
a relatively low contrast to noise ratio, potentially diminishing the visibility of HCC nodules as compared
to post contrast sequences used in the other AMRI approaches. The inclusion of DWI, a high-contrast
[47]
sequence, can aid in detecting liver lesions , thereby improving sensitivity. However, DWI is technically
[48]
challenging and often suffers from a variety of artifacts that can cause blind spots, most often near the
liver dome or in the left lobe. Many early stage HCCs may not exhibit restricted diffusion relative to liver.
[49]
In addition, HCC may be isointense to liver on T2 weighted imaging or obscured by altered signal in the
liver parenchyma in the setting of cirrhosis. Such HCCs may be difficult to visualize on NC-AMRI.

Studies to date
Several studies have retrospectively assessed the performance of a simulated NC-AMRI (derived by
extracting only the non-contrasted sequences from a complete MRI), most utilizing all three sequences
outlined above [23,25,32] , and some utilizing DWI alone [34,36] [Table 2]. While these studies found favorable
sensitivities ranging from 84%-92% on a per-patient basis, sensitivity was 78% on a per-lesion basis in one
[36]
study that used liver explant pathology as the reference standard MC . Most of these were retrospective
studies in predominantly hepatitis-B population without advanced cirrhosis, enriched with a high
prevalence of malignancy. Only one study thus far prospectively evaluated the performance of NC-AMRI
in an HCC surveillance population . Using DWI alone, this study demonstrated a sensitivity of 83% and
[34]
sensitivity of 98%. However, a small number of incident HCCs (n = 6) and low prevalence of Child Pugh