Effect of MRI Versus MDCT on Milan Criteria Scores and Liver Transplantation Eligibility

Hepatocellular Carcinoma: Optimal Radiological Evaluation before Liver Transplantation

Liver transplantation (LT) is the recommended curative-intent treatment for patients with early or intermediate-stage hepatocellular carcinoma (HCC) who are ineligible for resection. Imaging plays a central role in staging and for selecting the best LT candidates. This review will discuss recent developments in pre-LT imaging assessment, in particular LT eligibility criteria on imaging, the technical requirements and the diagnostic performance of imaging for the pre-LT diagnosis of HCC including the recent Liver Imaging Reporting and Data System (LI-RADS) criteria, the evaluation of the response to locoregional therapy, as well as the non-invasive prediction of HCC aggressiveness and its impact on the outcome of LT. We will also briefly discuss the role of nuclear medicine in the pre-LT evaluation and the emerging role of artificial intelligence models in patients with HCC.

Lipocalin-2: A novel diagnostic marker for hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide. Viral hepatitis, alcoholism and non-alcoholic steatohepatitis are the most common risk factors. Despite the advances in HCC screening and treatment options, HCC still has a high mortality rate and a high rate of recurrence after treatment. Lipocalin-2 (LCN-2) is a glycoprotein transporter that is highly expressed in HCC tissues.

OBJECTIVE

To evaluate serum LCN-2 as a diagnostic marker for HCC.

METHODS

The study was carried out in Zagazig university hospitals. It included 210 HCC patients (subdivided in three subgroups), 72 liver cirrhosis patients without HCC and 18 normal control persons (the total is 300 subjects). All the study subjects were evaluated by history taking, physical examination, routine laboratory investigations, alpha-fetoprotein (AFP) and LCN-2 in addition radiology.

RESULTS

In comparison between HCC and control, there was a statistically significant difference in hemoglobin percent (HB%), platelet count, serum ALT, AST, ALP, bilirubin, albumin and creatinine. In comparison to AFP, LCN-2 > 225 ng/ml had a higher diagnostic performance in HCC patients and was more accurate in differentiation between cirrhosis and HCC patients.

CONCLUSION

LCN-2 is a good candidate for HCC diagnosis and screening.

MRI-based radiomics model for preoperative prediction of 5-year survival in patients with hepatocellular carcinoma

Background

Recurrence is the major cause of mortality in patients with resected HCC. However, without a standard approach to evaluate prognosis, it is difficult to select candidates for additional therapy.

Methods

A total of 201 patients with HCC who were followed up for at least 5 years after curative hepatectomy were enrolled in this retrospective, multicentre study. A total of 3144 radiomics features were extracted from preoperative MRI. The random forest method was used for radiomics signature building, and five-fold cross-validation was applied. A radiomics model incorporating the radiomics signature and clinical risk factors was developed.

Results

Patients were divided into survivor (n = 97) and non-survivor (n = 104) groups based on the 5-year survival after surgery. The 30 most survival-related radiomics features were selected for the radiomics signature. Preoperative AFP and AST were integrated into the model as independent clinical risk factors. The model demonstrated good calibration and satisfactory discrimination, with a mean AUC of 0.9804 and 0.7578 in the training and validation sets, respectively.

Conclusions

This radiomics model is a valid method to predict 5-year survival in patients with HCC and may be used to identify patients for clinical trials of perioperative therapies and for additional surveillance.

Optimal criteria for hepatocellular carcinoma diagnosis using CT in patients undergoing liver transplantation

OBJECTIVE

To compare the diagnostic performance of various guidelines for hepatocellular carcinoma (HCC) diagnosis using computed tomography (CT) in patients undergoing liver transplantation (LT).

METHODS

In total, 216 patients who underwent preoperative CT and subsequent LT were included. Two radiologists retrospectively evaluated focal hepatic lesions independently according to various guidelines and allocated patients according to the Milan criteria. The diagnostic performance of the guidelines was compared using alternative free-response receiver-operating characteristics (AFROC) analysis with bootstrapping. Comparisons of sensitivity, specificity, and accuracy of patient allocation based on the Milan criteria between guidelines were performed using logistic regression with generalized estimating equations (GEE).

RESULTS

Fifty-two of 216 patients had 87 HCCs. The reader-averaged figure of merit obtained using AFROC analysis was 0.738 for the AASLD/EASL or KLCSG-NCC guidelines and 0.728 for the LI-RADS v2014 or OPTN/UNOS (bootstrapping, p = 0.005). The per-lesion sensitivity for HCCs (all and 1-2-cm lesions) was significantly higher with the AASLD/EASL (37.9-41.4% and 30.8-41.0%) than with LI-RADS (28.7% and 15.4-18.0%) (logistic regression with GEE, p = 0.008 and 0.030 for reader 1 and p = 0.005 for reader 2). The per-patient specificity (98.8-99.4%) was the same for all guidelines. The accuracy of the Milan criteria was 81.5-83.3% without significant differences among the four guidelines (logistic regression with GEE, p > 0.05).

CONCLUSION

AASLD/EASL showed higher diagnostic performance and sensitivity, particularly for 1-2-cm HCCs, and the same specificity with LI-RADS. All guidelines are comparable for patient allocation based on the Milan criteria for LT.

KEY POINTS

• The overall diagnostic performance of CT for HCC diagnosis was highest with AASLD/EASL. • AASLD/EASL showed higher sensitivity for diagnosis of 1-2-cm HCCs than LI-RADS. • The accuracy of the Milan criteria using CT was comparable among the four guidelines.

Post Locoregional Therapy Treatment Imaging in Hepatocellular Carcinoma Patients: A Literature-based Review

Imaging plays a crucial role in the diagnosis of hepatocellular carcinoma (HCC) as well as in determining treatment efficacy, or complications, following therapy. Unlike other cancers, HCC is most commonly treated by locoregional therapies (LRTs) such as thermal ablation, transarterial chemoembolization, and transarterial radioembolization. These treatments can lead to changes on imaging that make determination of residual/recurrent disease difficult. This literature-based review discusses the expected postimaging findings following LRT.

MRI for hepatocellular carcinoma: a primer for magnetic resonance imaging interpretation

Hepatocellular carcinoma is among the most prevalent solid organ cancers, and, unlike many cancers, may be diagnosed non-invasively by imaging criteria [1] with the preferred modality recently shifting from multiphasic computed tomography (MDCT) to magnetic resonance imaging (MRI). The purpose of this article is to help facilitate radiologists and radiology trainees in the transition to MRI by providing a step-wise approach to exam interpretation to improve the MRI detection of HCC. A methodical, consistent approach to navigating a HCC screening MRI exam, in conjunction with the LI-RADS framework for characterization, should lead to improved HCC detection and diagnosis.

Small hepatocellular carcinomas displayed as a ring enhancing mass on arterial phase MRI in the chronically diseased liver

AIM

To assess the prevalence of arterial phase (AP) ring-enhancing small hepatocellular carcinomas (HCC) on magnetic resonance imaging (MRI); detail additional MRI features that enable HCC diagnosis; and examine arterial timing as one possible cause of this appearance.

MATERIALS AND METHODS

Patients undergoing HCC screening with both computed tomography (CT) and MRI within 40 days were examined at a single institution over a 7- year time period ending in 2013. From this initial group, small (1-3 cm), (AP) ring-enhancing HCC on MRI were studied.

RESULTS

From the initial group of 64 patients with 129 HCC, 20 patients with 78 HCCs had a small diameter with 32 (41%) having an AP ring at MRI. The mean age of this latter group was 63-years old, with the average tumour diameter of 1.9 cm. Histopathology and secondary imaging supported a diagnosis of HCC in 20 (100%) patients and 31 (97%) lesions. Most of the ringed lesions had early AP timing.

CONCLUSION

This study revealed a high prevalence (41%) of small, AP ring HCC with MRI. The use of other MRI sequences adds support in making the proper diagnosis with this appearance. Early AP timing may help create this pattern.

Hepatocellular carcinoma: when is liver transplantation oncologically futile?

Selection criteria of patients with hepatocellular carcinoma (HCC) for liver transplantation (LT) have been progressively expanded since the introduction of the Milan criteria. Transplanting patients with unfavourable tumor characteristics increases the risk of tumor recurrence and impacts post-transplant survival. Although tumor number and size are the basis of widely accepted selection criteria and correlate with tumor grading and microvascular invasion, stronger predictors of tumor recurrence have been recently identified. These surrogates of aggressive tumor biology include non-response to pre-transplant treatment, rapid recurrence within the first months after treatment, increased alpha-fetoprotein (AFP) concentrations, ¹⁸F-FDG positron emission tomography (PET) positive HCCs and poor differentiation and microvascular invasion in histology. The presence of any of these risk factors significantly increases the risk of tumor recurrence in patients within and beyond the Milan criteria. Especially the combination of two or more of these factors is associated with an inacceptably high recurrence risk and can render LT oncologically futile even in patients not exceeding the Milan criteria. In contrast, in absence of these risk factors also patients exceeding expanded selection criteria may undergo LT with low recurrence risk and favourable post-transplant outcome. In selected cases this may even be applicable to patients with macrovascular invasion, who are conventionally excluded from LT. The main focus of this article is to review LT for HCC in the light of recurrence rates and to explore at what tumor stage transplantation becomes futile.

Multiparametric imaging for detection and characterization of hepatocellular carcinoma using gadoxetic acid-enhanced MRI and perfusion-CT: which parameters work best?

Background

MRI and perfusion-CT (PCT) are both useful imaging techniques for detection and characterization of liver lesions. The aim of this study was to compare the diagnostic accuracy of imaging parameters derived from PCT and gadoxetic acid-enhanced MRI in patients with hepatocellular carcinoma (HCC).

Methods

36 patients with liver cirrhosis and a total of 67 lesions referred to our hospital for multi-parametric diagnosis of HCC-suspected liver lesions in the setting of liver cirrhosis were prospectively enrolled and underwent PCT and MRI. HCC diagnosis was confirmed either by histology (n = 60) or interval growth (n = 7). For PCT, mean/max blood flow (BF), blood volume (BV), k-trans, arterial liver perfusion (ALP), portal venous perfusion (PVP) and hepatic perfusion index (HPI) were quantified. Two readers identified the lesions based on single maps each being blinded to the number of lesions.

MRI-protocol included fat-suppressed T1w-VIBE sequences obtained before, 2, 5, 10 and 20 min after the injection of gadoxetic acid as well as non-enhanced coronal HASTE, axial T1w-VIBE, fat-suppressed T2w-TSE and DWI. Quantitative analysis was performed using enhancement ratios between tumor and liver parenchyma for post-contrast in the hepatobiliary phase (RIR_HB), arterial (ER_a) and late-venous (ER_v) phases as well as signal intensity ratios (liver/parenchyma) on T1w (RIR_T1) and T2w (RIR_T2).

Results

In PCT analysis, all lesions exhibited high BF_max values (63–250 mL/100 g tissue) and were visible on HPI maps with high degrees of arterial blood supply of (HPI > 96%).

In MRI, RIR_HB was negative in 8/67. 12/67 HCCs were missed on DWI. 46/67 HCCs showed wash-in and 47/67 HCC showed wash-out of contrast agent. 6/67 HCCs were missed on T1w and 11/67 were missed on T2w-sequences when analyzed separately, while analysis of multiparametric MRI combining typical enhancement pattern, visibility on hepatobiliary phase and T1w-images the same number of lesions as PCT irrespective of their size (1–19 cm) were detected. Quantification of early enhancement by ER_a or ER_v did not improve detection rates.

Conclusions

Perfusion-CT and gadoxetic acid-enhanced MRI were comparable in detecting HCC lesions. For PCT a mean HPI > 96% proved to be a very robust parameter for detection and characterization of HCC.

Imaging prediction of residual hepatocellular carcinoma after locoregional therapy in patients undergoing liver transplantation or partial hepatectomy

PURPOSE

Locoregional therapies for hepatocellular carcinoma (HCC) offer alternatives for patients unable to undergo resection or awaiting transplant. We sought to evaluate the prevalence and interobserver agreement of imaging features suggestive of viable tumor at posttherapy CT/MRI and to determine a size threshold for tumor detection.

METHODS

Patients having undergone liver transplant or hepatectomy between 2012 and 2014 with presurgical embolization or ablation of HCC were identified. Imaging was retrospectively reviewed, and enhancement characteristics of each lesion were noted by two radiologists. Original pathology slides were reviewed, and the size of nodular viable tumor was noted, if present. Cohen's kappa was used to evaluate interobserver agreement.

RESULTS

87 patients with 129 HCCs were reviewed retrospectively following IRB approval. 50% (65/129) of lesions showed viable tumor at pathology. 86 lesions (67%) were imaged with CT and 43 (33%) with MR. Of viable lesions, 25 (38%) showed nodular arterial enhancement and 18 (28%) demonstrated washout. One lesion had capsule appearance. Sensitivity/specificity for nodular enhancement, washout, and capsule were 0.38/0.83, 0.28/0.89, and 0.02/1.00, respectively. Overall detection rate was 41% of <1 cm, 54% of 1-2 cm, and 57% of >2 cm viable lesions.

CONCLUSIONS

Nodular arterial enhancement was most frequently observed, followed by washout. Both showed moderate interobserver agreement. Sensitivity of any imaging feature was less than 50%, though findings were specific for viable disease. There is limited detection of nodules of viable tumor <1 cm and only marginal detection of larger lesions, though MRI outperformed CT for the detection of subcentimeter viable tumor.