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Longitudinal study of liver imaging reporting and Data system LR-2, LR-3 and LR-4 observations in cirrhosis on MRI
Fei Xing1, Xue qin Zhang1, Jian Lu1, and Xiao fen Miao 1
1The Third Hospital Affiliated of Nantong University, Nantong, China

Synopsis

Using LI-RADS v2018 on MRI, LR-2, LR-3 and LR-4 lesions in cirrhosis have different natural outcomes, LI-RADS lesions demonstrate increasing risk of progression to HCC with increasing category. About two-fifths of LR-4 observations progressed to a malignant category. LR-3 observations with APHE or threshold/subthreshold growth upgraded to LR-5 were significantly higher. Most LR-2 observations that remain stable in category for at least a year.

Introduction

Hepatocellular carcinoma (HCC), the most common primary hepatic malignancy worldwide, is a growing health care issue. Cirrhosis is the predominant risk factor for HCC, with 80% of HCC developing in a back-ground of cirrhosis. MRI plays a vital role in the diagnosis and staging of HCC, as early detection and treatment leads to improved outcomes. The Liver Imaging Reporting and Data System (LI-RADS) has been developed to standardize the terminology for reporting, assessing, and recommending action in liver imaging. The main purpose of LI-RADS is to minimize the likelihood of a false diagnosis of definite HCC. LI-RADS stratifies nodules into five categories according to the perceived risk of HCC. LR-1 (definitely benign) observations include cysts and typical hemangiomas. LR-5 (definitely HCC) observations demonstrate arterial phase hyper-enhancement in conjunction with one or more additional major features (washout appearance, capsule appearance, or threshold growth), taking into account the observation diameter. LR-2 (probably benign), LR-3 (intermediate probability for HCC), or LR-4(probably HCC) observations that are thought to have an intermediate and increasing likelihood of HCC. Although Tanabe and Hong et al previously demonstrated that observations categorized as LR-1, LR-2, LR-3, and LR-4 had different imaging outcomes, however those studies were limited by standardized imaging techniques, unable to assess longitudinal clinical outcomes with the recently released LI-RADS v2018, and few LR-2 observations progressed to LR-5. The purpose of this study was to characterize the MR imaging features and natural outcomes of LR-2, LR-3, and LR-4 nodules, with an emphasis on upgrade to LR-5 or higher by using LI-RADS v2018.

Methods

Data from 158 patients（245 lesions）of cirrhosis who underwent at least one follow-up magnetic resonance imaging (MRI) examination in our institution from May 2012 to September 2018, and were index category as LR-2, LR-3 and LR-4 lesions without biopsy or operation，were retrospectively reviewed. Among all the lesions, 105 were LR-2, 97 were LR-3 and 43 were LR-4. Follow-up duration and category modifications that progressed, remained stable, or decreased were recorded for each observation. The single-factor analysis was used to analyze the follow-up interval of LR-2, LR-3 and LR-4 lesions, and cumulative incidence curves for progression were analyzed using Kaplan-Meier method and Log-rank analysis by SPSS 22.0.

Results

The mean follow-up interval of LR-2, LR-3 and LR-4 were（20.5±11.4）,（18.1±10.5）and（13.8±9.9） months respectively, the difference were statistically significant（P=0.002）. Among 105 index LR-2 lesions, 5 upgraded to LR-5, 2 upgraded to LR-4, 4 upgraded to LR-3, 73 remained stable, and 23 decreased to LR-1. Among 97 index LR-3 lesions, 17 upgraded to LR-5, 6 upgraded to LR-4, 57 remained stable and 18 decreased to LR-1/-2. Among 43 index LR-4 lesions, 15 upgraded to LR-5, among them, 5 demonstrated threshold growth, 7 demonstrated subthreshold growth; 2 progressed to LR-TIV with venous invasion, 23 remained stable and 3 decreased to LR-1. The cumulative incidence of progression to LR-5/-TIV was higher for LR-4 lesions than for LR-3 or LR-2 lesions (each P＜.001). Among them, the cumulative incidence of upgraded to LR-5 in 3, 6, and 12 months, LR-4 lesions were 4.7%、11.6%、31.2%, LR-3 lesions were 0、4.2%、6.6% respectively, and LR-2 lesions were 0. The cumulative incidence of progression to LR≥4 was higher for LR-3 lesions than for LR-2 lesions (P＜.001).

Discussion

This study demonstrates that LR-2, LR-3, and LR-4 observations have significantly different longitudinal outcomes by using LI-RADS v2018. LR-2, LR-3, and LR-4 have an increasing likelihood of progression to malignant categories(LR-5 or LR-TIV): in particular, LR-2 observations have a cumulative incidence of progression to LR-5 of 0%, 0%, 0%, and 3.6% at 3 months, 6 months, 1 year, and 2 years, respectively; LR-3 observations have a cumulative incidence of progression to LR-5 of 0%, 4%, 9%, and 23%; and LR-4 observations have a cumulative incidence of progression to LR-5 of 5%, 12%, 31%, and 63%. In ourstudy, LR-2 observations were all homogeneous cirrhotic siderotic nodules(SN) that have no ancillary features(AF) malignancy, 4.8% (5/105) LR-2 SN progressed to LR-5, 6.7% of LR-2 SN upgrade to probable or definite HCC, iron clearance, hyperintense on T2WI and hypervascular transformation elevation on the follow-up MRI indicated the multi-step malignant evolution average within 22.5 months, suggested that LR-2 observations that remain stable in category for at least a year. 17.5% of index LR-3 observations progressed to LR-5 (four within 6months), 3 demonstrated threshold growth, 7 demonstrated subthreshold growth, and 23.7% progressed to either LR-4 or LR-5,LR-3 observations with APHE or threshold/subthreshold growth upgraded to LR-5 were significantly higher. In this study, most LR-4 observations have APHE, washout, and diameter less than 20 mm, approximately one-third of LR-4 observations upgrade to LR-5, 2 progressed to LR-TIV with venous invasion.

Conclusion

In summary, using LI-RADS v2018 on MRI, LR-2, LR-3 and LR-4 lesions in cirrhosis have different natural outcomes, 4.8% of LR-2 siderotic nodules, 17.5% of LR-3 and 34.9% LR-4 observations upgrade toLR-5/-TIV. LI-RADS lesions demonstrate increasing risk of progression to HCC with increasing category.

Acknowledgements

No acknowledgement found.

References

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Figures

Figure 1: Axial MRI obtained in a 64-year-old woman with an LR-2 observation that progressed to LR-5 (according to LI-RADS v2018). (a) T2WI shows a small (15-mm) SN in hepatic segment Ⅶ, and (b) DWI shows hypointensity. (c) Postcontrast T1WI in the arterial phase and (d) the equilibrium phase shows isointensity relative to liver parenchyma. (e) Fifteen months later, the observation with hyperintense on T2WI and (f) DWI has grown to 19mm. (g) Postcontrast T1WI, the observation shows arterial phase hyperenhancement (APHE) , and (h) shows washout in the equilibrium phase image.

Figure 2: Axial MRI obtained in a 49-year-old man with an LR-3 observation that progressed to LR-5 (according to LI-RADS version 2018). (a) T2WI shows a small (11-mm) hyperintense in hepatic segment Ⅵ/Ⅶ (arrow), (b) Postcontrast T1WI in the arterial phase demonstrates arterial phase hyperenhancement (APHE), and (c) shows an isointensity in the equilibrium phase image. (d) Six months later, the observation with hyperintense on T2WI has grown to 30mm (arrow), and (e) again demonstrates APHE. (f) In the equilibrium phase image shows washout as well as a newly depicted capsule.

Figure 3: Axial MRI obtained in a 51-year-old man with an LR-4 observation that progressed to LR-5 (according to LI-RADS version 2018). (a) T2WI shows a small (18-mm) hyperintense in hepatic segment Ⅷ (arrow), (b) Postcontrast T1WI in the arterial phase demonstrates arterial phase hyperenhancement (APHE), and (c) shows an isointensity in the equilibrium phase image with capsule. (d) Four months later, the observation with hyperintense on T2WI has grown to 32mm (arrow), and (e) again demonstrates APHE. (f) In the equilibrium phase image shows enhancing “capsule”without washout.

Figure 4 Graph shows the cumulative incidence of progression to LR-5 or LR-TIV for index LR-2, LR-3, and LR-4 observations and shows the cumulative incidence of progression to at least category LR-4 for index LR-2 and LR-3 observations (according to LI-RADS v2018)

Diagram illustrates the transitions in LI-RADS v2018 categories during follow-up (from baseline to final examination) for index LR-2, LR-3, and LR-4 included in this study


Proc. Intl. Soc. Mag. Reson. Med. 28 (2020)
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