Effects of ancillary features of gadoxetic acid-enhanced MRI on the categorization of hepatocellular carcinoma: validation of the Liver Imaging Reporting And Data System v2014
Ijin Joo1, Jeong Min Lee1, Dong Ho Lee1, Su Joa Ahn1, Eun Sun Lee2, and Joon Koo Han1

1Radiology, Seoul National University Hospital, Seoul, Korea, Republic of, 2Radiology, Chung-Ang University Hospital, Seoul, Korea, Republic of

Synopsis

The latest Liver Imaging Reporting And Data System (LI-RADS v2014) incorporates gadoxetic acid-enhanced MRI into the diagnostic algorithm of hepatocellular carcinoma (HCC). In this study, we investigated the effects of ancillary features of gadoxetic acid-enhanced MRI in the determination of LI-RADS categories of HCCs. On gadoxetic acid-enhanced MRI, LI-RADS showed sensitivities of 69.0% and 67.8% in the diagnosis of HCCs (LR-5/5v) in two reviewers, respectively. Ancillary features of HCCs on gadoxetic acid-enhanced MRI including hepatobiliary imaging features frequently resulted in upgrade LR-3 to LR-4.


Introduction

The Liver Imaging Reporting And Data System (LI-RADS), first launched in 2011 and recently updated in 2014, is a system for the standardized interpretation of CT and MRI in patients at high-risk of developing hepatocellular carcinoma (HCC).In the determination of LI-RADS categories, ancillary features that may favor HCC or benignity may be applied to adjust categories. The latest LI-RADS incorporates gadoxetic acid-enhanced MRI into the diagnostic algorithm of HCC, and hepatobiliary phase (HBP) specific features has been included in the ancillary features.

Purpose

To evaluate the effects of ancillary features of gadoxetic acid-enhanced MRI on the categorization of HCCs using the latest LI-RADS (v2014).

Materials and Methods

This retrospective study was approved by our institutional review board and the requirement for informed consent was waived. We included 201 patients at high-risk for developing HCCs with 239 pathologically-confirmed HCCs which were detectable on gadoxetic acid-enhanced MRI. Two independent radiologists assigned LI-RADS categorization before and after applying ancillary features without and with HBP features, respectively. Frequencies of changing LI-RADS categories according to ancillary features were investigated.

Definition of LI-RADS category

LR-1: definitely benign

LR-2: probably benign

LR-3: intermediate probability for HCC

LR-4: probably HCC

LR-5: definitely HCC

LR-5v: definitely HCC with tumor in vein

LR-M: probable malignancy, not specific for HCC

Results

On gadoxetic acid-enhanced MRI, sensitivities of final categories of LR-5/5V in the diagnosis of HCCs in reviewers 1 and 2 were 69.0% and 67.8%, respectively. Interobserver agreement of LR-3~5/5V assignment was almost perfect (weighted kappa = 0.810). When comparing LI-RADS categories before and after applying ancillary features, 14.2% and 10.0% of HCCs were changed their categories in reviewers 1 and 2, respectively (LR-3 to LR-4: 14.2% and 9.6%; and LR-4 to LR-3: 0% and 0.4%). Among ancillary features, HBP signal intensity affected the adjustment of category in 3.3% and 2.9% of cases, respectively.

Conclusion

LI-RADS categorization of HCCs on gadoxetic acid-enhanced MRI showed good interobserver agreement, and ancillary features including HBP features would frequently upgrade LR-3 into LR-4.

Acknowledgements

No acknowledgement found.

References

1. LI-RADS v2014, http://nrdr.acr.org/lirads/

2. Mitchell DG, Bruix J, Sherman M, Sirlin CB. LI-RADS (Liver Imaging Reporting and Data System): summary, discussion, and consensus of the LI-RADS Management Working Group and future directions. Hepatology 2015;61:1056-1065.

3. Hope TA, Fowler KJ, Sirlin CB, Costa EA, Yee J, Yeh BM, et al. Hepatobiliary agents and their role in LI-RADS. Abdom Imaging 2015;40:613-625.

4. Shah A, Tang A, Santillan C, Sirlin C. Cirrhotic liver: What's that nodule? The LI-RADS approach. J Magn Reson Imaging 2015.

5. Choi JY, Lee JM, Sirlin CB. CT and MR imaging diagnosis and staging of hepatocellular carcinoma: part II. Extracellular agents, hepatobiliary agents, and ancillary imaging features. Radiology 2014;273:30-50.

Figures

Figure 1. A surgically-proven HCC changing in LI-RADS category after applying ancillary features. There is a 3.2 cm observation showing arterial iso-enhancement and no washout appearance. The preliminary LI-RADS category without consideration of ancillary features was LR-3 for this case. However, after applying ancillary features (hepatobiliary phase hypo-intensity, diffusion restriction, T2 moderate hyper-intensity, and intralesional fat), the final LI-RADS category would be LR-4.



Proc. Intl. Soc. Mag. Reson. Med. 24 (2016)
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