Noncontrast MRI with diffusion-weighted imaging as the sole imaging modality for detecting liver malignancy in patients with high risk for hepatocellular carcinoma

Abbreviated magnetic resonance imaging in hepatocellular carcinoma surveillance: A review

Hepatocellular carcinoma (HCC) is one of the most common primary malignancies of the liver and a leading cause for cancer-related deaths worldwide. HCC surveillance aims at early detection. The recommended strategy for screening HCC is biannual ultrasound with or without alpha-fetoprotein. However, this strategy is associated with sub-optimal sensitivity. Abbreviated magnetic resonance imaging (AMRI) is a promising alternative to ultrasound (US) for surveillance of HCC. The data regarding the role of AMRI in HCC screening is evolving. There are different AMRI protocols, each having its merits and disadvantages. In this review, we discuss the need for AMRI, protocols of AMRI and hindrances to widespread adoption of AMRI.

Non-contrast abbreviated MRI for the detection of hepatocellular carcinoma in patients with Liver Imaging Reporting and Data System LR-3 and LR-4 observations in MRI

BACKGROUND AND AIMS

With ultrasound sensitivity limited in hepatocellular carcinoma (HCC) surveillance and few prospective studies on non-contrast abbreviated MRI (NC-AMRI), this study aimed to assess its diagnostic performance in detecting HCC.

METHODS

This prospective study involved cirrhotic patients with contrast-enhanced MRI (CE-MRI) Liver Imaging Reporting and Data System (LI-RADS) LR-3 and LR-4 observations detected during HCC surveillance. Patients underwent average 3 complete CE-MRI rounds at 3-6 months interval, with approximately 12-month follow-up. NC-AMRI included diffusion-weighted (DWI), T2-weighted imaging (T2WI), and T1-weighted imaging (T1WI). NC-AMRI protocol images were analysed for diagnostic performance, with subgroup analyses. CE-MRI and NC-AMRI images were independently reviewed by 2 experienced radiologists, with inter-reader agreement assessed with Kappa coefficient. The reference standard was the American Association for the Study of Liver Diseases-defined presence of arterial hypervascularity and washout during the portal-venous or delayed phases on CE-MRI.

RESULTS

In 166 CE-MRI follow-ups of 63 patients (median age: 63 years; 60.3% male, 39.7% female), 12 patients developed HCC, with average size of 19.6 mm. The NC-AMRI (DWI + T2WI + T1WI) showed 91.7% sensitivity (95%CI, 61.5-99.8) and 91.6% specificity (95%CI, 86.0-95.4), area under receiver operating characteristic 0.92 (95%CI, 0.83-1.00). Across different Body Mass Index categories, lesion size, Child-Turcotte-Pugh classes, Albumin-Bilirubin (ALBI) grades, and Model for End-Stage Liver Disease classes, sensitivity remained consistent. However, specificity differed significantly between ALBI grade 1 and 2 (86.7% vs. 98.4%, P = .010), and between viral and non-viral cirrhosis (93.8% vs. 80.8%, P = .010).

CONCLUSIONS

NC-AMRI proved clinically feasible, and exhibits high diagnostic performance in HCC detection.

ADVANCES IN KNOWLEDGE

This study highlights efficacy of NC-AMRI in detecting HCC among cirrhotic patients with LR-3 and LR-4 observations, representing significant progress in HCC surveillance.

MRI for hepatocellular carcinoma and the role of abbreviated MRI for surveillance of hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) constitutes the majority of liver cancers and significantly impacts global cancer mortality. While ultrasound (US) with or without alpha-fetoprotein is the mainstay for HCC surveillance, its limitations highlight the necessity for more effective surveillance tools. Therefore, this review explores evolving imaging modalities and abbreviated magnetic resonance imaging (MRI) (AMRI) protocols as promising alternatives, addressing challenges in HCC surveillance.

AREAS COVERED

This comprehensive review delves into the evaluation and challenges of HCC surveillance tools, focusing on non-contrast abbreviated MRI (NC-AMRI) and contrast-enhanced abbreviated MRI protocols. It covers the implementation of AMRI for HCC surveillance, patient preferences, adherence, and strategies for optimizing cost-effectiveness. Additionally, the article provides insights into prospects for HCC surveillance by summarizing meta-analyses, prospective studies, and ongoing clinical trials evaluating AMRI protocols.

EXPERT OPINION

The opinions underscore the transformative impact of AMRI on HCC surveillance, especially in overcoming US limitations. Promising results from NC-AMRI protocols indicate its potential for high-risk patient surveillance, though prospective studies in true surveillance settings are essential for validation. Future research should prioritize risk-stratified AMRI protocols and address cost-effectiveness for broader clinical implementation, alongside comparative analyses with US for optimal surveillance strategies.

Deep learning-based compressed SENSE improved diffusion-weighted image quality and liver cancer detection: A prospective study

PURPOSE

To assess whether diffusion-weighted imaging (DWI) with Compressed SENSE (CS) and deep learning (DL-CS-DWI) can improve image quality and lesion detection in patients at risk for hepatocellular carcinoma (HCC).

METHODS

This single-center prospective study enrolled consecutive at-risk participants who underwent 3.0 T gadoxetate disodium-enhanced MRI. Conventional DWI was acquired using parallel imaging (PI) with SENSE (PI-DWI). In CS-DWI and DL-CS-DWI, CS but not PI with SENSE was used to accelerate the scan with 2.5 as the acceleration factor. Qualitative and quantitative image quality were independently assessed by two masked reviewers, and were compared using the Wilcoxon signed-rank test. The detection rates of clinically-relevant (LR-4/5/M based on the Liver Imaging Reporting and Data System v2018) liver lesions for each DWI sequence were independently evaluated by another two masked reviewers against their consensus assessments based on all available non-DWI sequences, and were compared by the McNemar test.

RESULTS

67 participants (median age, 58.0 years; 56 males) with 197 clinically-relevant liver lesions were enrolled. Among the three DWI sequences, DL-CS-DWI showed the best qualitative and quantitative image qualities (p range, <0.001-0.039). For clinically-relevant liver lesions, the detection rates (91.4%-93.4%) of DL-CS-DWI showed no difference with CS-DWI (87.3%-89.8%, p = 0.230-0.231) but were superior to PI-DWI (82.7%-85.8%, p = 0.015-0.025). For lesions located in the hepatic dome, DL-CS-DWI demonstrated the highest detection rates (94.8%-97.4% vs 76.9%-79.5% vs 64.1%-69.2%, p = 0.002-0.045) among the three DWI sequences.

CONCLUSION

In patients at high-risk for HCC, DL-CS-DWI improved image quality and detection for clinically-relevant liver lesions, especially for the hepatic dome.

Combined Hounsfield units of hepatocellular carcinoma on computed tomography and PET as a noninvasive predictor of early recurrence after living donor liver transplantation: Time-to-recurrence survival analysis

BACKGROUND

Liver transplantation is an effective treatment for preventing hepatocellular carcinoma (HCC) recurrence. This retrospective study aimed to quantitatively evaluate the attenuation in Hounsfield units (HU) on contrast-enhanced computed tomography (CECT) as a prognostic factor for hepatocellular carcinoma (HCC) following liver transplantation as a treatment. Our goal is to optimize its predictive ability for early tumor recurrence and compare it with the other imaging modality-positron emission tomography (PET).

METHODS

In 618 cases of LDLT for HCC, only 131 patients with measurable viable HCC on preoperative CECT and preoperative positron emission tomography (PET) evaluations were included, with a minimum follow-up period of 6 years. Cox regression models were developed to identify predictors of postoperative recurrence. Performance metrics for both CT and PET were assessed. The correlation between these two imaging modalities was also evaluated. Survival analyses were conducted using time-dependent receiver operating characteristic (ROC) curve analysis and area under the curve (AUC) to assess accuracy and determine optimized cut-off points.

RESULTS

Univariate and multivariate analyses revealed that both arterial-phase preoperative tumor attenuation (HU) and PET were independent prognostic factors for recurrence-free survival. Both lower arterial tumor enhancement (Cut-off value = 59.2, AUC 0.88) on CT and PET positive (AUC 0.89) increased risk of early tumor recurrence 0.5-year time-dependent ROC. Composites with HU < 59.2 and a positive PET result exhibited significantly higher diagnostic accuracy in detecting early tumor recurrence (AUC = 0.96).

CONCLUSION

Relatively low arterial tumor enhancement values on CECT effectively predict early HCC recurrence after LDLT. The integration of CT and PET imaging may serve as imaging markers of early tumor recurrence in HCC patients after LDLT.

Abbreviated MRI for Hepatocellular Carcinoma Surveillance - A Systematic Review and Meta-analysis

BACKGROUND

Given the limited sensitivity of ultrasound in hepatocellular carcinoma (HCC) surveillance, this systematic review and meta-analysis were aimed to assess the diagnostic performance of non-contrast abbreviated MRI (NC-aMRI) compared to contrast-enhanced abbreviated MRI (CE-aMRI) for HCC surveillance, offering evidence-based guidance for clinical decision-making.

METHODS

A comprehensive search was conducted across five databases, identifying studies on aMRI for HCC surveillance. The pooled sensitivity and specificity were estimated using a random effects model. Subgroup analyses and meta-regression were performed by study location, proportion of patients with cirrhosis and HCC, and underlying liver diseases.

RESULTS

The meta-analysis included 27 studies (2009-2023), distributed between Western (n = 14) and Eastern (n = 13) countries. The pooled sensitivity and specificity (95%CI, I2) were 86% (83-88%, 63%) and 92% (90%-94%, 74%). The NC-aMRI protocols reported in 21 studies exhibited 83% (79-87%, 63%) sensitivity and 91% (88-93%, 67%) specificity, while the 15 studies on CE-aMRI protocols displayed 88% (84-91%, 64%) sensitivity and 94% (90-96%, 78%) specificity, with no statistically significant differences in sensitivity (p = 0.078) or specificity (p = 0.157). Subgroup analysis in NC-aMRI studies showed significant differences in sensitivity for high-prevalent chronic hepatitis B (87% vs. 78%, p = 0.003) and studies done in eastern countries (86% vs. 76%, p = 0.018). Additionally, specificity showed significant differences for high-prevalent chronic hepatitis C (94% vs. 90%, p = 0.009), with meta-regression identifying major sources of study heterogeneity as the inclusion of a majority of patients with chronic hepatitis B (p = 0.008) and the geographic regions where studies were conducted (p = 0.030).

CONCLUSION

Surveillance aMRI protocols exhibit satisfactory performance for detecting HCC. NC-aMRI may be used effectively for HCC surveillance, especially in chronic hepatitis B prevalent settings.

Non-contrast short MRI surveillance for HCC screening: the study protocol of the SMS-HCC prospective multicenter study

Hepatocellular carcinoma (HCC) comprises 75 to 85% of all primary liver cancers. Current guidelines recommend a biannual HCC surveillance using ultrasound (US) for high-risk patients. However, due to its low sensitivity for detection of early-stage HCC lesions, there is an urgency for more sensitive surveillance tools. Here, we describe the potential of a short MRI surveillance (SMS) protocol for HCC, including axial T1-weighted in-out phase, fat-saturated T2-weighted, and diffusion-weighted sequences. In this prospective, multicenter, patient cohort study, patients will be recruited from existing HCC surveillance cohorts of six medical centers in The Netherlands. Surveillance patients who undergo biannual US, will be invited for SMS on the same day for 3 years. In case of a suspicious finding on either US or SMS, patients will be invited for a full MRI liver protocol including gadolinium-based contrast agent intravenous injection within 2 weeks. To our knowledge, this will be the first study to perform a head-to-head comparison with a paired US-MRI design. We hypothesize that the sensitivity of SMS for detection of early-stage HCC will be higher than that of US leading to improved survival of surveillance patients through timely HCC diagnosis. Furthermore, we hypothesize that the SMS-HCC protocol will prove cost-effective.Relevance statement The US sensitivity for detecting early-stage HCC has been reported to be less than 50%. We expect that the proposed SMS will detect at least twice as many early-stage HCC lesions and therefore prove to be cost-effective. Key points • The low sensitivity of US necessitates better imaging tools for HCC screening.• This is the first study with a paired US-MRI design.• This design will allow a head-to-head comparison in both diagnostics and patient-acceptance.• We expect that SMS can contribute to a higher survival rate.

Impact of velocity- and acceleration-compensated encodings on signal dropout and black-blood state in diffusion-weighted magnetic resonance liver imaging at clinical TEs

PURPOSE

The study aims to develop easy-to-implement concomitant field-compensated gradient waveforms with varying velocity-weighting (M1) and acceleration-weighting (M2) levels and to evaluate their efficacy in correcting signal dropouts and preserving the black-blood state in liver diffusion-weighted imaging. Additionally, we seek to determine an optimal degree of compensation that minimizes signal dropouts while maintaining blood signal suppression.

METHODS

Numerically optimized gradient waveforms were adapted using a novel method that allows for the simultaneous tuning of M1- and M2-weighting by changing only one timing variable. Seven healthy volunteers underwent diffusion-weighted magnetic resonance imaging (DWI) with five diffusion encoding schemes (monopolar, velocity-compensated (M1 = 0), acceleration-compensated (M1 = M2 = 0), 84%-M1-M2-compensated, 67%-M1-M2-compensated) at b-values of 50 and 800 s/mm2 at a constant echo time of 70 ms. Signal dropout correction and apparent diffusion coefficients (ADCs) were quantified using regions of interest in the left and right liver lobe. The blood appearance was evaluated using two five-point Likert scales.

RESULTS

Signal dropout was more pronounced in the left lobe (19%-42% less signal than in the right lobe with monopolar scheme) and best corrected by acceleration-compensation (8%-10% less signal than in the right lobe). The black-blood state was best with monopolar encodings and decreased significantly (p < 0.001) with velocity- and/or acceleration-compensation. The partially M1-M2-compensated encoding schemes could restore the black-blood state again. Strongest ADC bias occurred for monopolar encodings (difference between left/right lobe of 0.41 μm2/ms for monopolar vs. < 0.12 μm2/ms for the other encodings).

CONCLUSION

All of the diffusion encodings used in this study demonstrated suitability for routine DWI application. The results indicate that a perfect value for the level of M1-M2-compensation does not exist. However, among the examined encodings, the 84%-M1-M2-compensated encodings provided a suitable tradeoff.

The combination of non-contrast abbreviated MRI and alpha foetoprotein has high performance for hepatocellular carcinoma screening

OBJECTIVES

This study aimed to compare two abbreviated MRI (AMRI) protocols to complete MRI for HCC detection: non-contrast (NC)-AMRI without/with alpha foetoprotein (AFP) and dynamic contrast-enhanced (Dyn)-AMRI.

METHODS

This retrospective single-center study included 351 patients (M/F: 264/87, mean age: 57y) with chronic liver disease, who underwent MRI for HCC surveillance between 2014 and 2020. Two reconstructed AMRI sets were obtained based on complete MRI: NC-AMRI (T2-weighted imaging (WI) + diffusion-WI) and Dyn-AMRI (T2-WI + dynamic T1-WI) and were assessed by 2 radiologists who reported all suspicious lesions, using LI-RADS/adapted LI-RADS classification. The reference standard was based on all available patient data. Inter-reader agreement was assessed and MRI diagnostic performance was compared to the reference standard.

RESULTS

The reference standard demonstrated 83/351 HCC-positive patients (prevalence: 23.6%, median size: 22 mm, and positive MRIs: 83/631). Inter-reader agreement was substantial for all sets. Sensitivities of Dyn-AMRI and complete MRI (both 92.8%) were similar, higher than NC-AMRI (72.3%, p < 0.001). Specificities were not different between sets. NC-AMRI + AFP (92.8%) had similar sensitivity to Dyn-AMRI and complete MRI. In patients with small size HCCs (≤ 2 cm), sensitivities of Dyn-AMRI (85.3%) and complete MRI (88.2%) remained similar (p = 0.564), also outperforming NC-AMRI (52.9%, p < 0.05). NC-AMRI + AFP had similar sensitivity (88.2%) to Dyn-AMRI and complete MRI (p = 0.706 and p = 1, respectively).

CONCLUSIONS

Dyn-AMRI has similar diagnostic performance to complete MRI for HCC detection, while both outperform NC-AMRI, especially for small size HCCs. NC-AMRI + AFP demonstrates similar sensitivity to Dyn-AMRI and complete MRI.

CLINICAL RELEVANCE STATEMENT

Due to the low sensitivity of ultrasound for hepatocellular screening, new screening methods are needed. Abbreviated MRI (AMRI) is a candidate, especially non-contrast AMRI with serum alpha foetoprotein as the acquisition time is low, without the need for contrast medium injection.

KEY POINTS

• Dynamic contrast-enhanced abbreviated MRI using extracellular gadolinium-based contrast agent and complete MRI have similar diagnostic performance for hepatocellular carcinoma detection in an at-risk population. • Non-contrast abbreviated MRI with alpha foetoprotein has similar diagnostic performance to dynamic contrast-enhanced abbreviated MRI and complete MRI, including when considering small size hepatocellular carcinoma  ≤ 2 cm. • Non-contrast abbreviated MRI and dynamic contrast-enhanced abbreviated MRI can be performed in 7 and 10 min, excluding patient setup time.

Screening of liver cancer with abbreviated MRI

Current recommendations for the surveillance of HCC are based on the semiannual liver ultrasound (with or without serum alpha-fetoprotein) in patients with cirrhosis and in subgroups with chronic hepatitis B infection. However, the sensitivity of this strategy is suboptimal for the detection of early-stage tumors, especially in obese patients, due to interoperator variability and poor adherence. The detection rate of focal liver lesions is excellent with MRI, making it the best alternative candidate for surveillance. However, performing a full contrast-enhanced MRI is unrealistic because of limited availability and health economics. Abbreviated MRI (AMRI) corresponds to the acquisition of a limited number of sequences with a high detection rate. The theoretical benefits of AMRI are a reduced acquisition time (≤10 min) with improved time-effectiveness and cost-effectiveness compared with conventional MRI, and greater accuracy than ultrasound. Numerous protocols may be performed, including T1-weighted, T2-weighted, and DWI sequences, with or without contrast administration. Although published studies report promising per-patient results, they should be interpreted with caution. Indeed, most studies were simulated, retrospectively reviewing a subset of sequences in relatively small populations who underwent a full MRI. They also included groups that were not representative of screening populations. In addition, most were published by Asian groups, with at-risk populations that were different from Western populations. There are no existing longitudinal studies that directly compare the different AMRI approaches or AMRI to ultrasound. Finally, it is possible that 1 approach will not fit all patients and that strategies should be tailored to the risk of HCC, in particular in relation to the cost and availability of AMRI. Several trials are ongoing to evaluate these questions.

Preoperative identification of cytokeratin 19 status of hepatocellular carcinoma based on diffusion kurtosis imaging

PURPOSE

To explore the potential value of diffusion kurtosis imaging (DKI) for identification of cytokeratin 19 (CK19) status of HCCs.

METHODS

This study was approved by the local institute review board and written informed consent was obtained. 73 patients with pathologically confirmed HCCs were included in this prospective study. All the diffusion-weighted (DW) images were acquired using a 3.0-T MR scanner with 4 b-values (0, 800, 1500 and 2000 s/mm²). The mean diffusion value (MD) and mean kurtosis coefficient (MK) from DKI, apparent diffusion coefficient (ADC) from DW imaging (b = 0, 500 s/mm²), and tumor-to-liver signal intensity ratios on ADC map (SIR_ADC) and DW images with b-value of 500 s/mm² (SIR_b500) were calculated and compared between CK19-positive (n = 23) and CK19-negative (n = 50) HCC groups. Univariate and multivariate logistic regression analyses were used to identify risk factors for the positive expression of CK19.

RESULTS

Increased a-fetoprotein level (p = 0.021) and SIR_b500 (p = 0.006) and decreased ADC (p = 0.021) and MD (p < 0.001) were significantly correlated with CK19-positive HCCs at univariate analysis. Decreased MD value (odds ratio: 0.042, p = 0.002) and a-fetoprotein level (odds ratio: 5.139, p = 0.015) were the independent risk factors for CK19-positive HCCs at multivariate analysis. The area under the curve of MD value by receiver operating characteristic analysis was 0.823 with a sensitivity of 86.96% and a specificity of 76% for the prediction of CK19-positive HCCs.

CONCLUSION

The decreased MD value derived from DKI is potential quantitative biomarker for predicting CK19-positive HCCs.

Development and validation of a clinical-radiomics model to predict recurrence for patients with hepatocellular carcinoma after curative resection

PURPOSE

Recurrence is the leading cause of death in hepatocellular carcinoma (HCC) patients with curative resection. In this study, we aimed to develop a preoperative predictive model based on high-throughput radiomics features and clinical factors for prediction of long- and short-term recurrence for these patients.

METHODS

A total of 270 patients with HCC who were followed up for at least 5 years after curative hepatectomy between June 2014 and December 2017 were enrolled in this retrospective study. Regions of interest were manually delineated in preoperative T2-weighted images using ITK-SNAP software on each HCC tumor slice. A total of 1197 radiomics features were extracted, and the recursive feature elimination method based on logistic regression was used for radiomics signature building. Tenfold cross-validation was applied for model development. Nomograms were constructed and assessed by calibration plot, which compares nomogram-predicated probability with observed outcome. Receiver-operating characteristic was then generated to evaluate the predictive performance of the model in the development and test cohorts.

RESULTS

The 10 most recurrence-free survival-related radiomics features were selected for the radiomics signatures. A multiparametric clinical-radiomics model combining albumin and radiomics score for recurrence prediction was further established. The integrated model demonstrated good calibration and satisfactory discrimination, with the area under the curve (AUC) of 0.864, 95% CI 0.842-0.903, sensitivity of 0.889, and specificity of 0.644 in the test set. Calibration curve showed good agreement concerning 5-year recurrence risk predicted by the nomogram. In addition, the AUC of 1-, 2-, 3-, and 4-year recurrence was 0.935 (95% CI 0.836-1.000), 0.861 (95% CI 0.723-0.999), 0.878 (95% CI 0.762-0.994), and 0.878 (95% CI 0.762-0.994) in the test set, respectively.

CONCLUSIONS

The clinical-radiomics model integrating radiomics features and clinical factors can improve recurrence predictions beyond predictions made using clinical factors or radiomics features alone. Our clinical-radiomics model is a valid method to predict recurrence that should improve preoperative prognostic performance and allow more individualized treatment decisions.

Performance of adding hepatobiliary phase image in magnetic resonance imaging for detection of hepatocellular carcinoma: a meta-analysis

OBJECTIVES

To determine the performance of diagnostic algorithm of adding hepatobiliary phase (HBP) images in Gd-EOB-DTPA-enhanced MRI for the detection of hepatocellular carcinoma (HCC) measuring up to 3 cm in patients with chronic liver disease.

METHODS

We searched multiple databases from inception to April 10, 2020, to identify studies on using Gd-EOB-DTPA-enhanced MRI for the diagnostic accuracy of HCC (≤ 3 cm) in patients with chronic liver disease. The diagnostic algorithm of Gd-EOB-DTPA-enhanced MRI with HBP for HCC was defined as a nodule showing hyperintensity during arterial phase and hypointensity during the portal venous, delayed, or hepatobiliary phases. For gadoxetic acid-enhanced MRI without HBP, the diagnostic criteria were a nodule showing arterial enhancement and hypointensity on the portal venous or delayed phases. The data were extracted to calculate summary estimates of sensitivity, specificity, diagnostic odds ratio, likelihood ratio, and summary receiver operating characteristic (sROC) by using a bivariate random-effects model.

RESULTS

Twenty-nine studies with 2696 HCC lesions were included. Overall Gd-EOB-DTPA-enhanced MRI with HBP had a sensitivity of 87%, specificity of 92%, and the area under the sROC curve of 95%. The summary sensitivity of Gd-EOB-DTPA-enhanced MRI with HBP was significantly higher than that without HBP (84% vs 68%, p = 0.01).

CONCLUSION

Gd-EOB-DTPA-enhanced MRI with HBP showed higher sensitivity than that without HBP and had comparable specificity for diagnosis of HCC in patients with chronic liver disease.

KEY POINTS

• Hypointensity on HBP is a major feature for diagnosis of HCC. • Extending washout appearance to the transitional or hepatobiliary phase on Gd-EOB-DTPA provides favorable sensitivity and comparable specificity for diagnosis HCC. • The summary sensitivity of gadoxetic acid-enhanced MRI with HBP was significantly higher than that without HBP (84% vs 68%, p = 0.01) for diagnosis of HCC in patients with chronic liver disease.

The clinical value of dual-energy computed tomography and diffusion-weighted imaging in the context of liver cancer: A narrative review

The dual-energy computed tomography (DECT) and diffusion-weighted magnetic resonance imaging (DWI-MRI) are used to diagnose liver cancer. The clinical value of these two examination methods needs to be further summarized. We collected and summarized relevant literature published from 2011 to 2021. The diagnostic performance of DECT was assessed between conventional computed tomography and DWI-MRI. DWI-MRI had a 69% sensitivity for detecting small hepatocellular carcinoma (HCC) lesions and a 60% diagnostic specificity for differentiating between types of HCC lesions. DECT had a sensitivity to small liver lesions (<1 cm) of 69%, and the diagnostic specificity for HCC and metastasis was about 60%. DWI was more sensitive (90.3% vs. 74.9%) and accurate (91.9% vs. 76.9%) in diagnosing HCC compared with conventional MRI sequencing. With the aid of contrast media, DWI-MRI had 90.0% specificity for detecting small HCCs (smaller than 1 cm). Furthermore, DWI-MRI not only provided physicians with valuable diagnostic information but also delivered histological grading information, with 78% accuracy for all benign lesions and 71% for solid lesions. DECT had relatively high sensitivity and required a lower contrast medium dose. With standardized quantitative parameters, it can be an extremely useful tool for HCC surveillance. DWI-MRI is the preferred imaging process as it produces high-contrast images for supporting an early diagnosis (high sensitivity and specificity) and provides histological information using non-ionizing radiation.

Noncontrast MRI for Hepatocellular Carcinoma Detection: A Systematic Review and Meta-analysis - A Potential Surveillance Tool?

BACKGROUND AND AIMS

This meta-analysis investigates the diagnostic performance of non-contrast magnetic resonance imaging (MRI) for the detection of hepatocellular carcinoma (HCC).

METHODS

A systematic review was performed to May 2020 for studies which examined the diagnostic performance of non-contrast MRI (multi-sequence or diffusion-weighted imaging (DWI)- alone) for HCC detection in high risk patients. The primary outcome was accuracy for the detection of HCC. Random effects models were used to pool outcomes for sensitivity, specificity, positive likelihood ratio (LR) and negative LR. Subgroup analyses for cirrhosis and size of the lesion were performed.

RESULTS

Twenty-two studies were included involving 1685 patients for per-patient analysis and 2128 lesions for per-lesion analysis. Multi-sequence non-contrast MRI (NC-MRI) using T2+DWI±T1 sequences had a pooled per-patient sensitivity of 86.8% (95%CI:83.9-89.4%), specificity of 90.3% (95%CI:87.3-92.7%), and negative LR of 0.17 (95%CI:0.14-0.20). DWI-only MRI (DW-MRI) had a pooled sensitivity of 79.2% (95%CI:71.8-85.4%), specificity of 96.5% (95%CI:94.3-98.1%) and negative LR of 0.24 (95%CI:1.62-0.34). In patients with cirrhosis, NC-MRI had a pooled per-patient sensitivity of 87.3% (95%CI:82.7-91.0%) and specificity of 81.6% (95%CI:75.3-86.8%), whilst DWI-MRI had a pooled sensitivity of 71.4% (95%CI:60.5-80.8%) and specificity of 97.1% (95%CI:91.9-99.4%). For lesions <2 cm, the pooled per-lesion sensitivity was 77.1% (95%CI:73.8-80.2%). For lesions >2 cm, pooled per-lesion sensitivity was 88.5% (95%CI:85.0-91.5%).

CONCLUSION

Non-contrast MRI has a moderate negative LR and high specificity with acceptable sensitivity for the detection of HCC, even in patients with cirrhosis and with lesions <2 cm. Prospective trials to validate if non-contrast MRI can be used for HCC surveillance is warranted.

Abbreviated MR Protocols for Chronic Liver Disease and Liver Cancer

MR imaging has become a powerful tool for assessing liver disease and liver cancer; however, it entails complex, time-consuming, and costly protocols. Abbreviated MR imaging (AMRI) is emerging as a simpler, faster, and low-cost alternative to full-abdominal MR imaging protocols. Different AMRI approaches have been tested successfully in hepatocellular carcinoma detection and for assessment of diffuse liver disease. The most accurate, time-effective, and cost-effective protocol as well as the target population need to be defined. Prospective and multicentric studies, exploring different AMRI protocols versus the current standard of reference, should be performed.

Abbreviated MRI for hepatocellular carcinoma screening: A systematic review and meta-analysis

BACKGROUND & AIMS

Biannual ultrasound has poor sensitivity for hepatocellular carcinoma (HCC) screening. MRI is accurate for the detection of HCC, but a complete MRI is not feasible as a screening tool. Abbreviated MRI (AMRI) is an acceptable alternative. The diagnostic performance of different AMRI protocols is not known. We performed a systematic review to determine the diagnostic accuracy of AMRI for HCC screening.

METHODS

We searched the MEDLINE and EMBASE databases for studies reporting the diagnostic accuracy of AMRI for HCC screening. The pooled sensitivity and specificity of different AMRI protocols were calculated based on a random intercept logistic regression model. The diagnostic performance of AMRI was compared with ultrasound. Study quality was assessed using the QUADAS-2 tool.

RESULTS

Of the 11,327 studies screened by titles, 15 studies (3 prospective and 12 retrospective: 2,807 patients, 917 with HCC) were included in the final analysis. The pooled per-patient sensitivity and specificity were 86% (95% CI 84-88%, I² 0%) and 94% (95% CI 91-96%, I² 83%), respectively. Pooled per-lesion sensitivity was 77% (95% CI 74-81%, I² 8%). There was no influence of study type, screening setting, reference standard, and presence and etiology of cirrhosis on the performance of AMRI. The sensitivity of AMRI for detection of HCC <2 cm was lower than that for HCC ≥2 cm (69% vs. 86%). The sensitivity and specificity of non-contrast AMRI were comparable to contrast-enhanced AMRI (86% and 94% vs. 87% and 94%, respectively). The diagnostic performance of different non-contrast AMRI and contrast-enhanced AMRI protocols was comparable. The sensitivity of ultrasound was lower than AMRI (53% vs. 82%).

CONCLUSIONS

AMRI has high sensitivity and specificity for HCC screening. Different AMRI protocols have comparable diagnostic performance.

LAY SUMMARY

Abbreviated MRI (AMRI) has been suggested as an alternative to ultrasound and complete MRI for hepatocellular carcinoma (HCC) screening. Our study results showed that AMRI has a high per-patient and per-lesion sensitivity for HCC. Although the sensitivity of AMRI for detection of HCC <2 cm is considerably lower than for HCC ≥2 cm, it is substantially higher than ultrasound, making it a potential alternative for HCC screening in high-risk populations.

Meta-Analysis of the Accuracy of Abbreviated Magnetic Resonance Imaging for Hepatocellular Carcinoma Surveillance: Non-Contrast versus Hepatobiliary Phase-Abbreviated Magnetic Resonance Imaging

Simple Summary

Ultrasonography is recommended as a standard surveillance modality, but the performance of surveillance ultrasound for detecting early-stage hepatocellular carcinoma (HCC) is limited. Motivated to provide a more sensitive method, abbreviated magnetic resonance imaging (AMRI) protocols have been introduced for HCC surveillance. We aimed to systematically determine the diagnostic performance of surveillance AMRI for detecting HCC. This meta-analysis of 10 studies comprising 1547 patients found that the pooled sensitivity and specificity of surveillance AMRI for detecting HCC were 86% and 96%, respectively. Hepatobiliary phase contrast-enhanced AMRI showed significantly higher sensitivities for detecting HCC than non-contrast AMRI (87% vs. 82%), but significantly lower specificities (93% vs. 98%). Therefore, surveillance AMRI had overall good diagnostic performance for detecting HCC and might be clinically useful for HCC surveillance. In addition, AMRI protocol should be selected with consideration of the advantages and disadvantages of each protocol.

Abstract

We aimed to determine the performance of surveillance abbreviated magnetic resonance imaging (AMRI) for detecting hepatocellular carcinoma (HCC), and to compare the performance of surveillance AMRI according to different protocols. Original research studies reporting the performance of surveillance AMRI for the detection of HCC were identified in MEDLINE, EMBASE, and Cochrane databases. The pooled sensitivity and specificity of surveillance AMRI were calculated using a hierarchical model. The pooled sensitivity and specificity of contrast-enhanced hepatobiliary phase (HBP)-AMRI and non-contrast (NC)-AMRI were calculated and compared using bivariate meta-regression. Ten studies, including 1547 patients, reported the accuracy of surveillance AMRI. The pooled sensitivity and specificity of surveillance AMRI for detecting any-stage HCC were 86% (95% confidence interval (CI), 80–90%; I² = 0%) and 96% (95% CI, 93–98%; I² = 80.5%), respectively. HBP-AMRI showed a significantly higher sensitivity for detecting HCC than NC-AMRI (87% vs. 82%), but significantly lower specificity (93% vs. 98%) (p = 0.03). Study quality and MRI magnet field strength were factors significantly associated with study heterogeneity (p ≤ 0.01). In conclusion, surveillance AMRI showed good overall diagnostic performance for detecting HCC. HBP-AMRI had significantly higher sensitivity for detecting HCC than NC-AMRI, but lower specificity.

Assessment of SE-MRE-derived shear stiffness at 3.0 Tesla for solid liver tumors characterization

OBJECTIVES

To evaluate the feasibility and diagnostic value of using a 2D spin-echo MR elastography (SE-MRE) sequence at 3.0 Tesla for solid focal liver lesions (FLL) characterization.

METHODS

This prospective study included 55 patients with solid FLL (size > 20 mm), who underwent liver SE-MRE at 3 Tesla between 2016 and 2019. Stiffness measurements were performed by two independent readers blinded to the complete MRI exam or patient information. Histological confirmation or typical behavior on the complete MRI exam evaluated in consensus by expert abdominal radiologists was used as reference standard. FLLs were grouped and compared (malignant vs. benign) using the Mann-Whitney and Kruskal-Wallis tests. MRE diagnostic performance was assessed, and stiffness cutoffs were obtained by analysis of ROC curves from accuracy maximization. A linear regression plot was used to evaluate inter-rater agreement for FLLs stiffness measurements. p values < 0.05 were considered statistically significant.

RESULTS

The final study group comprised 57 FLLs (34 malignant, 23 benign). Stiffness measurements were technically successful in 91.23% of lesions. To both readers, the median stiffness of the lesions categorized as benign was 4.5 ± 1.5 kPa and in the malignant group 6.8 ± 1.7 and 7.5 ± 1.5 kPa depending on the reader. A cutoff of 5.8 kPa distinguished malignant and benign lesions with 88% specificity and 75-85% accuracy depending on the reader. The inter-rater agreement was 0.90 ± 0.04 with a correlation coefficient of 0.94.

CONCLUSION

2D-SE-MRE at 3.0 T provides high specificity and PPV to differentiate benign from malignant liver lesions. Trial registration 18FFUA-A02.

Abbreviated MRI Protocol for the Assessment of Ablated Area in HCC Patients

Background: Liver Imaging Reporting and Data Systems (LI-RADS) Treatment Response Algorithm (TRA) was created to provide a standardized assessment of hepatocellular carcinoma (HCC) following loco regional therapy. The aim of this study was to compare sensitivity of standard MRI protocol versus abbreviated protocol (only T1-Weigthed fat suppressed (FS) sequences pre- and post-contrast phase) in the detection of ablated area according to LI-RADS Treatment Response (LR-TR) categories. Methods: From January 2015 to June 2020, we selected 64 patients with HCC, who underwent Radiofrequency ablation (RFA) or Microwave ablation (MWA) treatment. According to inclusion criteria, 136 pathologically proven treated HCC (median 2, range 1–3 per patient; mean size 20.0 mm; range 15–30 mm) in 58 patients (26 women, 32 men; median age, 74 years; range, 62–83 years) comprised our study population. For each ablated area, abbreviated protocol, and standard Magnetic Resonance Imaging (MRI) studies were independently and blindly assessed in random order within and between three expert radiologists. Each radiologist assessed the ablated area by using the following categories: “LR-TR Non-viable” = 1; “LR-TR Equivocal” = 2 and “LR-TR Viable” = 0. Results: According to the concordance between MRI and Contrast enhancement ultrasound (CEUS) among 136 treated HCCs, 115 lesions were assessed as non-viable or totally ablate and 21 as viable or partially ablate. The accuracy for standard MRI protocol and abbreviated MRI protocol for predicting pathologic tumor viability of a consensus reading was 98.6% (sensitivity = 100%; specificity = 98.3%; positive predictive value = 91.3% and negative predictive value = 100%). No differences were found in sensitivity or specificity between standard MRI LR-TR viable and abbreviated MRI LR-TR viable categories (p value > 0.05 at McNemar test). Conclusion: The abbreviated dynamic protocol showed similar diagnostic accuracy to conventional MRI study in the assessment of treated HCCs, with a reduction of the acquisition study time of 30% respect to conventional MRI.

[Recent Updates of Abbreviated MRI for Hepatocellular Carcinoma Screening]

International guidelines recommended screening with ultrasonography (US) every 6 months for patients at risk for hepatocellular carcinoma (HCC). However, US demonstrates low sensitivity for the early detection of HCC. Magnetic resonance imaging (MRI) plays an important role in the noninvasive diagnosis of HCC, but it is not suitable for surveillance due to its lengthy examination and high cost. Therefore, several studies have been using various abbreviated MRI strategies, including noncontrast abbreviated MRI, dynamic contrast-enhanced abbreviated MRI, and abbreviated MRI using hepatobiliary phase image for HCC surveillance. In this article, we aim to review these various strategies and explore the future direction of HCC surveillance considering the cost-effectiveness aspect.

Ultrasound or Sectional Imaging Techniques as Screening Tools for Hepatocellular Carcinoma: Fall Forward or Move Forward?

Hepatocellular carcinoma (HCC) is probably the epitome of a screening target, with a well-defined high-risk population, accessible screening methods, and multiple curative-intent treatments available for early disease. Per major societies guideline consensus, biannual ultrasound (US) surveillance of the at-risk patients is the current standard of care worldwide. Yet, despite its documented success in the past decades, this standard is far from perfect. While the whole community is working to further tighten the knots, a worrying number of cases still slip through this safety net. Consequently, these patients lose their chance to a curative solution which leads to a high disease burden with disproportionate mortality. While US will probably remain the fundamental staple in the screening strategy, key questions are seeking better answers. How can its caveats be addressed, and the technique be improved? When are further steps needed? How to increase accuracy without giving up on accessibility? This narrative review discusses the place of US surveillance in the bigger HCC picture, trying to navigate through its strengths and limits based on the most recent available evidence.

Current status of image-based surveillance in hepatocellular carcinoma

Although the overall prognosis of patients with hepatocellular carcinoma (HCC) remains poor, curative treatment may improve the survival of patients diagnosed at an early stage through surveillance. Accordingly, ultrasonography (US)-based HCC surveillance programs proposed in international society guidelines are now being implemented and regularly updated based on the latest evidence to improve their efficacy. Recently, other imaging modalities such as magnetic resonance imaging have shown potential as alternative surveillance tools based on individualized risk stratification. In this review article, we describe the current status of US-based surveillance for HCC and summarize the supporting evidence. We also discuss alternative surveillance imaging modalities that are currently being studied to validate their diagnostic performance and cost-effectiveness.

Abbreviated MRI protocol for colorectal liver metastases: How the radiologist could work in pre surgical setting

Background

MRI is the most reliable imaging modality that allows to assess liver metastases. Our purpose is to compare the per-lesion and per-patient detection rate of gadoxetic acid-(Gd-EOB) enhanced liver MRI and fast MR protocol including Diffusion Weighted Imaging (DWI) and T2-W Fat Suppression sequence in the detection of liver metastasis in pre surgical setting.

Methods

One hundred and eight patients with pathologically proven liver metastases (756 liver metastases) underwent Gd-EOBMRI were enrolled in this study. Three radiologist independently graded the presence of liver lesions on a five-point confidence scale assessed only abbreviated protocol (DWI and sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE) fat suppressed sequence) and after an interval of more than 2 weeks the conventional study (all acquired sequences). Per-lesion and per-patient detection rate of metastases were calculated. Weighted к values were used to evaluate inter-reader agreement of the confidence scale regarding the presence of the lesion.

Results

MRI detected 732 liver metastases. All lesions were identified both by conventional study as by abbreviated protocol. In terms of per-lesion detection rate of liver metastasis, all three readers had higher detection rate both with abbreviated protocol and with standard protocol with Gd-EOB (96.8% [732 of 756] vs. 96.5% [730 of 756] for reader 1; 95.8% [725 of 756] vs. 95.2% [720 of 756] for reader 2; 96.5% [730 of 756] vs. 96.5% [730 of 756] for reader 3). Inter-reader agreement of lesions detection rate between the three radiologists was excellent (k range, 0.86–0.98) both for Gd-EOB MRI and for Fast protocol (k range, 0.89–0.99).

Conclusion

Abbreviated protocol showed the same detection rate than conventional study in detection of liver metastases.

Abbreviated MRI for Hepatocellular Carcinoma Screening and Surveillance

To detect potentially curable hepatocellular carcinoma (HCC), clinical practice guidelines recommend semiannual surveillance US of the liver in adult patients at risk for developing this malignancy, such as those with cirrhosis and some patients with chronic hepatitis B infection. However, cirrhosis and a large body habitus, both of which are increasingly prevalent in the United States and the rest of the world, may impair US visualization of liver lesions and reduce the sensitivity of surveillance with this modality. The low sensitivity of US for detection of early-stage HCC contributes to delayed diagnosis and increased mortality. Abbreviated MRI, a shortened MRI protocol tailored for early-stage detection of HCC, has been proposed as an alternative surveillance option that provides high sensitivity and specificity. Abbreviated MRI protocols include fewer sequences than a complete multiphase MRI examination and are specifically designed to identify small potentially curable HCCs that may be missed at US. Three abbreviated MRI strategies have been studied: (a) nonenhanced, (b) dynamic contrast material-enhanced, and (c) hepatobiliary phase contrast-enhanced abbreviated MRI. Retrospective studies have shown that simulated abbreviated MRI provides high sensitivity and specificity for early-stage HCC, mostly in nonsurveillance cohorts. If it is supported by scientific evidence in surveillance populations, adoption of abbreviated MRI could advance clinical practice by increasing early detection of HCC, allowing effective treatment and potentially prolonging life in the growing number of individuals with this cancer. Online supplemental material is available for this article. ©RSNA, 2020.

Comparison of multiplexed sensitivity encoding and single-shot echo-planar imaging for diffusion-weighted imaging of the liver

PURPOSE

To compare multiplexed sensitivity encoding (MUSE) and conventional diffusion-weighted magnetic resonance imaging (cDWI) techniques in liver MRI.

METHODS

Fifty-nine patients who underwent both two-shot echo-planar DWI using MUSE and single-shot echo-planar cDWI at a 3.0-T MRI system were included. Qualitative parameters were independently evaluated by three radiologists, and quantitative parameters were calculated on the basis of region of interest measurements. Receiver operating characteristic curve analysis and McNemar's test were used to compare solid lesion characterization results and lesion detectability, respectively.

RESULTS

All reviewers found less image noise, sharper liver contours, milder susceptibility artifacts, and better lesion conspicuity in MUSE-DWI than in cDWI (reader average mean, 4.1-4.5 vs. 3.5-4.0; p < 0.05). The signal-to-noise ratio (SNR) of the liver was significantly higher in MUSE-DWI than in cDWI (right lobe: mean, 9.39 vs. 8.10, p < 0.001; left lobe: mean, 8.34 vs. 7.19, p < 0.001), while the SNR of the lesion (mean, 23.72 vs. 23.88, p = 0.911) and lesion-to-liver contrast-to-noise ratio (mean, 14.65 vs. 15.41, p = 0.527) were comparable between MUSE-DWI and cDWI. Solid lesion characterization results were comparably accurate between MUSE-DWI and cDWI (reader average area under the receiver operating characteristic curve, 0.985 vs. 0.986, p = 0.480). The detectability of lesions was better in MUSE-DWI than in cDWI (reader consensus, 83.7 % [41/49] vs. 67.3 % [33/49], p = 0.021).

CONCLUSION

MUSE-DWI can provide multi-shot liver DWI with less noise, fewer distortions, improved SNR of the liver, and better lesion detectability.

Alternative approach of hepatocellular carcinoma surveillance: abbreviated MRI

This review focuses on emerging abbreviated magnetic resonance imaging (AMRI) surveillance of patients with chronic liver disease for hepatocellular carcinoma (HCC). This surveillance strategy has been proposed as a high-sensitivity alternative to ultrasound for identification of patients with early-stage HCC, particularly in patients with cirrhosis or obesity, in whom sonographic visualization of small tumors may be compromised. Three general AMRI approaches have been developed and studied in the literature - non-contrast AMRI, dynamic contrast-enhanced AMRI, and hepatobiliary phase contrast-enhanced AMRI - each comprising a small number of selected sequences specifically tailored for HCC detection. The rationale, general technique, advantages and disadvantages, and diagnostic performance of each AMRI approach is explained. Additionally, current gaps in knowledge and future directions are discussed. Based on emerging evidence, we cautiously recommend the use of AMRI for HCC surveillance in situations where ultrasound is compromised.

Imaging Modalities for Hepatocellular Carcinoma Surveillance: Expanding Horizons beyond Ultrasound

In Asian countries favoring loco-regional treatment such as surgical resection or ablation, very early-stage hepatocellular carcinoma (HCC) should be the main target for surveillance. Even though ultrasound (US) has been accepted as a primary imaging modality for HCC surveillance, its performance in detecting very early-stage HCCs is insufficient. Moreover, in more than 20% of patients at high risk for HCC, visualization of the liver on US may be limited owing to the advanced distortion and heterogeneity of the liver parenchyma. Recently revised HCC clinical guidelines allow the use of alternative surveillance tools including computed tomography or magnetic resonance imaging in patients with inadequate US exams. This paper summarizes the findings of recent studies using imaging modalities other than US as surveillance tools for HCC as well as strengths and limitations of these modalities.

Evaluation of non-contrast magnetic resonance imaging as an imaging surveillance tool for hepatocellular carcinoma in at-risk patients

INTRODUCTION

This study aimed to evaluate the potential of non-contrast enhanced magnetic resonance (MR) imaging as an imaging surveillance tool for hepatocellular carcinoma (HCC) detection in at-risk patients and to compare the performance of non-contrast MR imaging with ultrasonography (US) as a screening modality for the same.

METHODS

In this retrospective study, patients diagnosed with HCC between 1 January 2010 and 31 December 2015 were selected from our institution's cancer registry. Patients with MR imaging and US scanning performed within three months of the MR imaging were included. For each MR imaging, two non-contrast MR imaging sequences - T2-weighted fat-saturated sequence (T2w-FS) and diffusion-weighted imaging (DWI) - were reviewed for the presence of suspicious lesions. A non-contrast MR image was considered positive if the lesion was seen on both sequences. The performance of non-contrast MR imaging was compared to that of hepatobiliary US for the detection of HCC.

RESULTS

A total of 73 patients with 108 HCCs were evaluated. Sensitivity of non-contrast MR imaging for the detection of HCC using T2w-FS and DWI was 93.2%, which was significantly higher than that of US, at 79.5% (p = 0.02). In a subgroup of 55 patients with imaging features of liver cirrhosis, the sensitivity of non-contrast MR imaging was 90.9%, which was also significantly higher than US, at 74.5% (p = 0.02).

CONCLUSION

Our pilot study showed that non-contrast MR imaging, using a combination of T2w-FS and DWI, is a potential alternative to US as a screening tool for the surveillance of patients at risk for HCC.

Abbreviated Magnetic Resonance Imaging Protocols in the Abdomen and Pelvis

In recent decades, the clinical applications for which magnetic resonance (MR) imaging is routinely used have expanded exponentially. MR imaging protocols have become increasingly complex, adversely affecting image acquisition and interpretation times. The MR imaging workflow has become a prime target for process improvement initiatives. There has been growing interest in the cultivation of abbreviated MR imaging protocols that evaluate specific clinical questions while reducing cost and increasing access. The overarching goal is to streamline the MR imaging workflow and reduce the time needed to obtain and report examinations by eliminating duplicative or unnecessary sequences without sacrificing diagnostic accuracy.

Automatic needle tracking using Mask R-CNN for MRI-guided percutaneous interventions

PURPOSE

Accurate needle tracking provides essential information for MRI-guided percutaneous interventions. Passive needle tracking using MR images is challenged by variations of the needle-induced signal void feature in different situations. This work aimed to develop an automatic needle tracking algorithm for MRI-guided interventions based on the Mask Region Proposal-Based Convolutional Neural Network (R-CNN).

METHODS

Mask R-CNN was adapted and trained to segment the needle feature using 250 intra-procedural images from 85 MRI-guided prostate biopsy cases and 180 real-time images from MRI-guided needle insertion in ex vivo tissue. The segmentation masks were passed into the needle feature localization algorithm to extract the needle feature tip location and axis orientation. The proposed algorithm was tested using 208 intra-procedural images from 40 MRI-guided prostate biopsy cases, and 3 real-time MRI datasets in ex vivo tissue. The algorithm results were compared with human-annotated references.

RESULTS

In prostate datasets, the proposed algorithm achieved needle feature tip localization error with median Euclidean distance (dxy) of 0.71 mm and median difference in axis orientation angle (dθ) of 1.28°, respectively. In 3 real-time MRI datasets, the proposed algorithm achieved consistent dynamic needle feature tracking performance with processing time of 75 ms/image: (a) median dxy = 0.90 mm, median dθ = 1.53°; (b) median dxy = 1.31 mm, median dθ = 1.9°; (c) median dxy = 1.09 mm, median dθ = 0.91°.

CONCLUSIONS

The proposed algorithm using Mask R-CNN can accurately track the needle feature tip and axis on MR images from in vivo intra-procedural prostate biopsy cases and ex vivo real-time MRI experiments with a range of different conditions. The algorithm achieved pixel-level tracking accuracy in real time and has potential to assist MRI-guided percutaneous interventions.

Gadoxetate-enhanced abbreviated MRI is highly accurate for hepatocellular carcinoma screening

OBJECTIVES

The primary objective was to compare the performance of 3 different abbreviated MRI (AMRI) sets extracted from a complete gadoxetate-enhanced MRI obtained for hepatocellular carcinoma (HCC) screening. Secondary objective was to perform a preliminary cost-effectiveness analysis, comparing each AMRI set to published ultrasound performance for HCC screening in the USA.

METHODS

This retrospective study included 237 consecutive patients (M/F, 146/91; mean age, 58 years) with chronic liver disease who underwent a complete gadoxetate-enhanced MRI for HCC screening in 2017 in a single institution. Two radiologists independently reviewed 3 AMRI sets extracted from the complete exam: non-contrast (NC-AMRI: T2-weighted imaging (T2wi)+diffusion-weighted imaging (DWI)), dynamic-AMRI (Dyn-AMRI: T2wi+DWI+dynamic T1wi), and hepatobiliary phase AMRI (HBP-AMRI: T2wi+DWI+T1wi during the HBP). Each patient was classified as HCC-positive/HCC-negative based on the reference standard, which consisted in all available patient data. Diagnostic performance for HCC detection was compared between sets. Estimated set characteristics, including historical ultrasound data, were incorporated into a microsimulation model for cost-effectiveness analysis.

RESULTS

The reference standard identified 13/237 patients with HCC (prevalence, 5.5%; mean size, 33.7 ± 30 mm). Pooled sensitivities were 61.5% for NC-AMRI (95% confidence intervals, 34.4-83%), 84.6% for Dyn-AMRI (60.8-95.1%), and 80.8% for HBP-AMRI (53.6-93.9%), without difference between sets (p range, 0.06-0.16). Pooled specificities were 95.5% (92.4-97.4%), 99.8% (98.4-100%), and 94.9% (91.6-96.9%), respectively, with a significant difference between Dyn-AMRI and the other sets (p < 0.01). All AMRI methods were effective compared with ultrasound, with life-year gain of 3-12 months against incremental costs of US$ < 12,000.

CONCLUSIONS

NC-AMRI has limited sensitivity for HCC detection, while HBP-AMRI and Dyn-AMRI showed excellent sensitivity and specificity, the latter being slightly higher for Dyn-AMRI. Cost-effectiveness estimates showed that AMRI is effective compared with ultrasound.

KEY POINTS

• Comparison of different abbreviated MRI (AMRI) sets reconstructed from a complete gadoxetate MRI demonstrated that non-contrast AMRI has low sensitivity (61.5%) compared with contrast-enhanced AMRI (80.8% for hepatobiliary phase AMRI and 84.6% for dynamic AMRI), with all sets having high specificity. • Non-contrast and hepatobiliary phase AMRI can be performed in less than 14 min (including set-up time), while dynamic AMRI can be performed in less than 17 min. • All AMRI sets were cost-effective for HCC screening in at-risk population in comparison with ultrasound.

Non-enhanced magnetic resonance imaging as a surveillance tool for hepatocellular carcinoma: Comparison with ultrasound

BACKGROUND & AIMS

Recently revised international guidelines for hepatocellular carcinoma (HCC) suggest that patients with inadequate ultrasonography be assessed by alternative imaging modalities. Non-enhanced MRI has potential as a surveillance tool based on the short scan times required and the absence of contrast agent-associated risks. This study compared the performance of non-enhanced MRI and ultrasonography for HCC surveillance in high-risk patients.

METHODS

We included 382 high-risk patients in a prospective cohort who underwent 1 to 3 rounds of paired gadoxetic acid-enhanced MRI and ultrasonography. Non-enhanced MRI, consisting of diffusion-weighted imaging (DWI) and T2-weighted imaging, was simulated and retrospectively analyzed, with results considered positive when lesion(s) ≥1 cm showed diffusion restriction or mild-moderate T2 hyperintensity. Ultrasonography results were retrieved from patient records. HCC was diagnosed histologically and/or radiologically. Sensitivity, positive predictive value (PPV), specificity, and negative predictive value (NPV) were evaluated using generalized estimating equations.

RESULTS

Forty-eight HCCs were diagnosed in 43 patients. Per-lesion and per-exam sensitivities of non-enhanced MRI were 77.1% and 79.1%, respectively, which were higher than those achieved with ultrasonography (25.0% and 27.9%, respectively, p <0.001). Specificities of non-enhanced MRI (97.9%) and ultrasonography (94.5%) differed significantly (p <0.001). NPV was higher for non-enhanced MRI (99.1%) than ultrasonography (96.9%). Per-lesion and per-exam PPVs were higher for non-enhanced MRI (56.9% and 61.8%, respectively) than for ultrasonography (16.7% and 17.7%, respectively). The estimated scan time of non-enhanced MRI was <6 min.

CONCLUSION

Based on its good performance, short scan times, and the lack of contrast agent-associated risks, non-enhanced MRI is a promising option for HCC surveillance in high-risk patients.

LAY SUMMARY

Recently revised international guidelines for hepatocellular carcinoma (HCC) suggest that selected patients with inadequate surveillance on ultrasonography be assessed by alternative imaging modalities such as computed tomography or magnetic resonance imaging (MRI). Herein, we show that MRI without contrast agents performed significantly better than ultrasonography for HCC surveillance in high-risk patients. Given this good performance, as well as short scan times and the lack of contrast agent-associated risks, non-enhanced MRI is a promising option for HCC surveillance in high-risk patients.

Diagnostic performance of a minimized protocol of non-contrast MRI for hepatocellular carcinoma surveillance

PURPOSE

To evaluate the per-patient diagnostic performance of a minimized non-contrast MRI protocol for hepatocellular carcinoma (HCC) surveillance in cirrhotic liver, as well as factors affecting diagnostic sensitivity.

METHODS

A total of 226 patients who underwent MRI for HCC surveillance over an 8 year period were included in this retrospective study. Set1 consisted of diffusion-weighted imaging and respiratory-triggered, fast-spin echo T2-weighted imaging with fat suppression. Set2 included T1-weighted in/opposed-phase images added to the images from Set1. Image sets were scored as positive or negative for HCC according to predetermined criteria by two readers independently. The diagnostic performance of the two sets in conjunction with α-fetoprotein (AFP) was assessed and compared using the McNemar test. Logistic regression was used to determine factors that affected sensitivity.

RESULTS

The sensitivity, specificity, and accuracy of Set1 of readers 1 and 2 were 84.4%/87.3%, 86.8%/86.8%, and 85.0%/87.2%, respectively; and those for Set2 were 87.3%/89.6%, 81.1%/79.2%, and 85.8/87.2%, respectively. The sensitivities of the sets were not significantly different (p = 0.063). Sensitivities of both sets in conjunction with AFP were higher than those of MRI alone without statistical significance (87.3%/89.6%, p = 0.063/> 0.99; 89.6%/89.6%, p = 0.125/> 0.99). In very early-stage HCC, the sensitivities of Sets1 and 2 were 73.1%/76.9% and 76.9%/82.7%, respectively. Perihepatic ascites and size less than 2 cm were associated with sensitivity (p < 0.05).

CONCLUSIONS

A minimized non-contrast MRI protocol consisting of Fat-sat T2WI and DWI is highly sensitive and may be a viable method for HCC surveillance of the cirrhotic liver. The inclusion of T1-weighted in/opposed-phase and AFP may increase this sensitivity.

Abbreviated MRI with optional multiphasic CT as an alternative to full-sequence MRI: LI-RADS validation in a HCC-screening cohort

OBJECTIVE

To compare the diagnostic performance of abbreviated MRI (AMRI) combined with multiphasic CT (mCT) with that of full-sequence gadoxetic acid-enhanced MRI (EOB-MRI) in a hepatocellular carcinoma (HCC)-screening cohort METHODS: Consecutive patients at risk of HCC who underwent EOB-MRI and mCT within 3 months for evaluation of new 0.5-3-cm hepatic observations were retrospectively recruited from 3 centers. An AMRI protocol comprising hepatobiliary phase, T2- and diffusion-weighted imaging, and dual-echo sequence was reconstituted from EOB-MRI. Two radiologists independently reviewed each observation in AMRI plus mCT (set 1) and EOB-MRI (set 2) per LI-RADS v2018. Per-lesion sensitivity, accuracy, and positive predictive value (PPV) for HCC were calculated and compared between image sets.

RESULTS

In 267 patients, 306 histologically confirmed observations (280 HCCs, 20 combined hepatocellular-cholangiocarcinomas, 1 cholangiocarcinoma, and 5 benignities) were assessed. Set 1 yielded higher sensitivity (96.4% vs. 92.9%, p = 0.013) and comparable accuracy (91.2% vs. 87.6%) and PPV (94.1% vs. 93.5%) to set 2 using LI-RADS category (LR)-4/5 criteria. The sets showed comparable sensitivity (66.4% vs. 70.4%), accuracy (67.7% vs. 70.6%), and PPV (97.4% vs. 96.6%) using LR-5 criteria. A similar substantial number of non-HCC malignancies were categorized as LR-4 or LR-5, as was the number of HCCs categorized as LR-M in both sets.

CONCLUSIONS

AMRI combined with mCT showed diagnostic performance similar or superior to that of EOB-MRI for HCC diagnosis using LI-RADS. Therefore, mCT holds potential as a sequential examination for HCC diagnosis in AMRI-detected hepatic observation in patients at risk of HCC.

KEY POINTS

• AMRI plus multiphasic CT showed comparable accuracy (91.2%) and PPV (94.1%) to full-sequence gadoxetic acid-enhanced MRI using LR-4/5 criteria. • AMRI plus multiphasic CT was significantly more sensitive than full-sequence gadoxetic acid-enhanced MRI (96.4% vs. 92.9%) using LR-4/5 criteria. • Multiphasic CT is a potential sequential modality for HCC diagnosis after AMRI.

Hepatocellular carcinoma surveillance: Eastern and Western perspectives

Eastern and Western guidelines for the management of hepatocellular carcinoma (HCC) are known to significantly differ on many points, because they reflect different diagnostic and therapeutic approaches to this cancer. Importantly, these guidelines are primarily consensus-driven when it comes to surveillance, both in term of the tests used and surveillance program design. The main difference between East and West lies in clinical practice, as several Eastern countries implement coordinated and systematic surveillance programs, while most Western countries rely on individual adherence to surveillance recommendations. This review article presents an overview of the evidence supporting surveillance programs for HCC, with a particular focus on the efficacy, cost-effectiveness, and consequences of this approach for patient survival. Western and Eastern guideline recommendations are discussed.

Noncontrast magnetic resonance imaging versus ultrasonography for hepatocellular carcinoma surveillance (MIRACLE-HCC): study protocol for a prospective randomized trial

BACKGROUND

Biannual ultrasound (US)-with or without alpha-fetoprotein (AFP)-is recommended by current guidelines for the surveillance of hepatocellular carcinoma (HCC). However, the inadequate sensitivity of US has been a concern. Magnetic resonance imaging (MRI) is known to have high sensitivity in detecting hepatic malignancies, even without contrast enhancement. The purpose of our study is to compare US with noncontrast (unenhanced) MRI for HCC surveillance of high-risk patients.

METHODS/DESIGN

MIRACLE-HCC (usefulness of noncontrast MagnetIc Resonance imAging versus nonContrast ultrasonography for surveiLlancE of HepatoCellular Carcinoma) is a prospective, single-center, nonblinded, balanced-randomized, parallel-group study. This study was approved by our institutional review board, and informed consent will be obtained from all participating patients. All patients with compensated liver cirrhosis will undergo noncontrast US or MRI, with serum AFP testing every 6 months. If a suspicious lesion is newly detected, or if the serum AFP level is elevated in an increasing trend for two consecutive tests, dynamic contrast-enhanced imaging will be performed to confirm the diagnosis. The primary endpoints are detection rates of very early or early stage HCC, stage distribution at the initial diagnosis, and false positive referral rates, which will be compared using Fisher's exact or chi-square tests. The study will include 416 patients in a tertiary academic medical center in South Korea.

DISCUSSION

MIRACLE-HCC is the first prospective randomized trial to compare the effectiveness of noncontrast MRI and noncontrast US in the surveillance of HCC in at-risk patients. The results of this trial will show whether noncontrast MRI surveillance is superior to noncontrast US surveillance in the early detection of HCC. The trial will also determine whether there are fewer false referrals with noncontrast MRI than with noncontrast US and, eventually, whether there is improvement in the overall survival of HCC patients.

TRIAL REGISTRATION

The date of trial registration (ClincalTrials.gov: NCT02514434 ) for this study is July 23, 2015. Enrollment of participants was finished in November 2017. No authors have relationships, conditions, or circumstances that present potential conflicts of interest.

Detection of recurrent hepatocellular carcinoma after surgical resection: Non-contrast liver MR imaging with diffusion-weighted imaging versus gadoxetic acid-enhanced MR imaging

OBJECTIVE:

To compare the diagnostic performance of non-contrast liver MRI to whole MRI using gadoxetic acid for detection of recurrent hepatocellular carcinoma (HCC) after hepatectomy.

METHODS:

This retrospective study analyzed 483 patients who underwent surveillance with liver MRI after hepatectomy for HCC (median time interval, 7.7 months). Non-contrast MRI set (T₁- and T₂ weighted and diffusion-weighted images) and whole MRI set (gadoxetic acid-enhanced and non-contrast MRI) were analyzed independently by two observers. Receiver operating characteristic analysis was used (with the observers' individual observations and consensus) to detect recurrent HCC. The accuracy, sensitivity, and specificity were calculated.

RESULTS:

A total of 113 patients had 197 recurrent HCCs on first follow-up MRI. Although non-contrast MRI had fairly high sensitivity for recurrent HCC, there were significant differences in sensitivity (94.7% vs 99.1%, p = 0.025) and accuracy (97.5% vs 99.2%, p = 0.021) between the two image sets (per-patients base analysis). However, in patients followed for ≥1 year after surgery, the diagnostic performance of non-contrast MRI and whole MRI were not significantly different (p > 0.05).

CONCLUSION:

Non-contrast MRI may serve as an alternative follow-up method which can potentially replace whole MRI at least in selected patients followed up ≥1 year after surgery who have relatively lower risk of HCC recurrence.

ADVANCES IN KNOWLEDGE:

There is no consensus regarding the ideal imaging modality or follow-up interval after resection of HCC. Non-contrast MRI had comparable performance to that of gadoxetic acid-enhanced MRI in the detection of HCC recurrence during surveillance ≥1 year after surgery.

The Diagnostic Performance of Liver MRI without Intravenous Contrast for Detecting Hepatocellular Carcinoma: A Case-Controlled Feasibility Study

Objective

To preliminarily evaluate the diagnostic performance of an unenhanced MRI for detecting hepatocellular carcinoma (HCC) with a case-control study design.

Materials and Methods

The case group consisted of 175 patients with initially-diagnosed HCC, who underwent a 3T liver MRI. A total of 237 HCCs were identified. The number of HCCs that were smaller than 1 cm, 1 cm ≤ and < 2 cm, and ≥ 2 cm were 19, 105, and 113, respectively. For the control group, 72 patients with chronic liver disease, who did not have HCC, were enrolled. Two radiologists independently reviewed the T2 half-Fourier acquisition single-shot turbo spin echo, T2 fast spin echos with fat saturation, T1 gradient in- and out-of-phase images, and diffusion-weighted images/apparent diffusion coefficient maps to detect HCC. Per-patient analyses were performed to evaluate the sensitivity and specificity of the non-contrast MRI for diagnosing HCC. Furthermore, the per-lesion sensitivity was also calculated according to tumor size.

Results

In the per-patient analyses, the sensitivity and specificity of reader 1 were 86.3% (151/175) and 87.5% (63/72), respectively; while those of reader 2 were 82.9% (145/175) and 76.4% (55/72), respectively. When excluding HCCs smaller than 1 cm, the sensitivity of reader 1 and 2 were 88.0% (147/167) and 86.2% (144/167), respectively. In the per-lesion analyses, the sensitivities of reader 1 and reader 2 were 75.9% (180/237) and 70.5% (167/237), respectively.

Conclusion

The per-patient sensitivity and specificity of non-contrast MRIs were within a reasonable range for the initial diagnosis of HCC. Non-contrast MRIs may have a potential for surveillance of HCC. Further confirmatory diagnostic test accuracy studies are needed.

Hepatocellular carcinoma surveillance with ultrasound-cost-effectiveness, high-risk populations, uptake

Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer and the second cause of cancer-related deaths worldwide. In most cases, it is diagnosed in patients with identified risk factors, mainly cirrhosis from all causes. These patients are candidates for a surveillance program that, depending on guidelines, involves regular liver ultrasound alone or combined with serum markers. These programs have been shown to improve the oncological outcome by detecting earlier stage tumors and providing patients with potentially curative treatment and improved survival. Yet, the level of evidence supporting these guidelines remains limited. This review article presents an overview of the evidence supporting surveillance programs for hepatocellular carcinoma, in particular the efficacy, cost-effectiveness, and consequences of this approach for patient survival. Western and Eastern guideline recommendations are described and discussed.

Comparison of biannual ultrasonography and annual non-contrast liver magnetic resonance imaging as surveillance tools for hepatocellular carcinoma in patients with liver cirrhosis (MAGNUS-HCC): a study protocol

Background

Ultrasonography (US) is recommended as a standard surveillance tool for patients with a high risk of developing hepatocellular carcinoma (HCC). However, the low sensitivity of US for small HCC can lead to surveillance failure, resulting in advanced stage tumor presentations. For the early detection of HCC in high-risk patients and to improve survival and prognosis, a new efficient imaging tool with a high sensitivity for HCC detection is needed. The purpose of this study is to evaluate and compare the feasibility and efficacy of non-contrast magnetic resonance imaging (MRI) with US as a surveillance tool for HCC in patients with liver cirrhosis.

Methods

MAGNUS-HCC is a prospective, multicenter clinical trial with a crossover design for a single arm of patients. This study was approved by six Institutional Review Boards, and informed consent was obtained from all participants. All patients will undergo liver US every 6 months and non-contrast liver MRI every 12 months during a follow-up period of 3 years. If a focal liver lesion suspected of harboring HCC is detected, dynamic liver computed tomography (CT) will be performed to confirm the diagnosis. After the last surveillance round, patients without suspicion of HCC or who are not diagnosed with HCC will be evaluated with a dynamic liver CT to exclude false-negative findings. The primary endpoint is to compare the rate of detection of HCC by US examinations performed at 6-month intervals with that of yearly non-contrast liver MRI studies during a 3-year follow-up. The secondary endpoint is the survival of the patients who developed HCC within the 3-year follow-up period.

Discussion

MAGNUS-HCC is the first study to compare the feasibility of non-contrast MRI with US as a surveillance tool for the detection of HCC in high-risk patients. We anticipate that the evidence presented in this study will establish the efficacy of non-contrast MRI as a surveillance tool for HCC in high-risk patients.

Trial registration

The date of trial registration (NCT02551250) in this study was September 15, 2015, and follow-up is still ongoing.

Diagnostic accuracy of diffusion-weighted whole-body imaging with background body signal suppression/T2-weighted image fusion for the detection of abdominal solid cancer

Diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) images show significant contrast for cancer tissues against non-cancerous tissues. Fusion of a DWIBS and a T2-weighted image (DWIBS/T2) can be used to obtain functional, as well as anatomic, information. In the present study, the performance of DWIBS/T2 in the diagnosis of abdominal solid cancer was evaluated. The records of 14 patients were retrospectively analyzed [5 patients with hepatocellular carcinoma (HCC), 4 with metastatic liver cancer, 3 with pancreatic cancer, 1 with renal cellular carcinoma and 1 with malignant lymphoma of the para-aortic lymph node]. T1WI and T2WI scans did not detect pancreatic cancer in certain cases, whereas DWIs and DWIBS/T2 clearly demonstrated pancreatic cancer in all cases. In addition, metastatic liver cancer and HCC were successfully detected with abdominal US and CECT; however, US did not detect pancreatic cancer in 1 case, while CECT and DWIBS/T2 detected pancreatic cancer in all cases. In conclusion, the diagnostic performance of DWIBS/T2 was the same as that of abdominal US and CECT in detecting primary and metastatic liver cancer. DWIBS/T2 enabled the diagnosis of pancreatic cancer in cases where it was not detected with US, T1WI or T2WI.

Image quality and diagnostic performance of free-breathing diffusion-weighted imaging for hepatocellular carcinoma

AIM

To retrospectively evaluate the diagnostic performance of free-breathing diffusion-weighted imaging (FB-DWI) with modified imaging parameter settings for detecting hepatocellular carcinomas (HCCs).

METHODS

Fifty-one patients at risk for HCC were scanned with both FB-DWI and respiratory-triggered DWI with the navigator echo respiratory-triggering technique (RT-DWI). Qualitatively, the sharpness of the liver contour, the image noise and the chemical shift artifacts on each DWI with b-values of 1000 s/mm² were independently evaluated by three radiologists using 4-point scoring. We compared the image quality scores of each observer between the two DWI methods, using the Wilcoxon signed-rank test. Quantitatively, we compared the signal-to-noise ratios (SNRs) of the liver parenchyma and lesion-to-nonlesion contrast-to-noise ratios (CNRs) after measuring the signal intensity on each DWI with a b-factor of 1000 s/mm². The average SNRs and CNRs between the two DWI methods were compared by the paired t-test. The detectability of HCC on each DWI was also analyzed by three radiologists. The detectability provided by the two DWI methods was compared using McNemar’s test.

RESULTS

For all observers, the averaged image quality scores of FB-DWI were: Sharpness of the liver contour [observer (Obs)-1, 3.08 ± 0.81; Obs-2, 2.98 ± 0.73; Obs-3, 3.54 ± 0.75], those of the distortion (Obs-1, 2.94 ± 0.50; Obs-2, 2.71 ± 0.70; Obs-3, 3.27 ± 0.53), and the chemical shift artifacts (Obs-1, 3.38 ± 0.60; Obs-2, 3.15 ± 1.07; Obs-3, 3.21 ± 0.85). The averaged image quality scores of RT-DWI were: Sharpness of the liver contour (Obs-1, 2.33 ± 0.65; Obs-2, 2.37 ± 0.74; Obs-3, 2.75 ± 0.81), distortion (Obs-1, 2.81 ± 0.56; Obs-2, 2.25 ± 0.74; Obs-3, 2.96 ± 0.71), and the chemical shift artifacts (Obs-1, 2.92 ± 0.59; Obs-2, 2.21 ± 0.85; Obs-3, 2.77 ± 1.08). All image quality scores of FB-DWI were significantly higher than those of RT-DWI (P < 0.05). The average SNR of the normal liver parenchyma by FB-DWI (11.0 ± 4.8) was not significantly different from that shown by RT-DWI (11.0 ± 5.0); nor were the lesion-to-nonlesion CNRs significantly different (FB-DWI, 21.4 ± 17.7; RT-DWI, 20.1 ± 15.1). For all three observers, the detectability of FB-DWI (Obs-1, 43.6%; Obs-2, 53.6%; and Obs-3, 45.0%) was significantly higher than that of RT-DWI (Obs-1, 29.1%; Obs-2, 43.6%; and Obs-3, 34.5%) (P < 0.05).

CONCLUSION

FB-DWI showed better image quality and higher detectability of HCC compared to RT-DWI, without significantly reducing the SNRs of the liver parenchyma and lesion-to-nonlesion CNRs.

Hepatocellular carcinoma detection: diagnostic performance of a simulated abbreviated MRI protocol combining diffusion-weighted and T1-weighted imaging at the delayed phase post gadoxetic acid

PURPOSE

The purpose of this study was to evaluate the diagnostic performance of a "simulated" abbreviated MRI (AMRI) protocol using diffusion-weighted imaging (DWI) and T1-weighted (T1w) imaging obtained at the hepatobiliary phase (HBP) post gadoxetic acid injection alone and in combination, compared to dynamic contrast-enhanced (CE)-T1w imaging for the detection of hepatocellular carcinoma (HCC).

METHODS

This was an IRB approved HIPAA compliant retrospective single institution study including patients with liver disease who underwent gadoxetic acid-enhanced MRI for HCC diagnosis. Three independent observers assessed 2 sets of images (full CE-set and AMRI including DWI+T1w-HBP). Diagnostic performance of T1w-HBP and DWI alone and in combination was compared to that of CE-set. All imaging sets included unenhanced T1w and T2w sequences. A preliminary analysis was performed to assess cost savings of AMRI protocol compared to a full MRI study.

RESULTS

174 patients including 62 with 80 HCCs were assessed. Equivalent per-patient sensitivity and negative predictive value (NPV) were observed for DWI (85.5% and 92.2%, pooled data) and T1w-HBP (89.8% and 94.2%) (P = 0.1-0.7), while these were significantly lower for the full AMRI protocol (DWI+T1w-HBP, 80.6% and 80%, P = 0.02) when compared to CE-set (90.3% and 94.9%). Higher specificity and positive predictive value were observed for CE-set vs. AMRI (P = 0.02). The estimated cost reduction of AMRI versus full MRI ranged between 30.7 and 49.0%.

CONCLUSION

AMRI using DWI and T1w-HBP has a clinically acceptable sensitivity and NPV for HCC detection. This could serve as the basis for a future study assessing AMRI for HCC screening and surveillance.

Performance of Gadoxetic Acid-Enhanced Liver Magnetic Resonance Imaging for Predicting Patient Eligibility for Liver Transplantation Based on the Milan Criteria

PURPOSE

This study aimed to evaluate the accuracy of gadoxetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI) in predicting eligibility for liver transplantation in patients with hepatocellular carcinoma (HCC) based on Milan criteria (MC).

MATERIALS AND METHODS

We reviewed Gd-EOB-MRI of 44 patients who underwent liver transplantation for HCC with cirrhosis for the presence/size of HCCs, vascular invasion, and transplant eligibility based on MC. Hepatocellular carcinoma was diagnosed based on conventional radiological hallmarks (arterial enhancement and washout) or the modified criteria.

RESULTS

Among 44 patients, 16 was beyond MC. Sensitivity, specificity, and accuracy of conventional radiological hallmark and the modified criteria for predicting eligibility by MC were 31.3%, 96.3%, and 72.7%, and 68.8%, 96.3%, and 86.4%, respectively.

CONCLUSIONS

Gd-EOB-MRI showed high specificity but poor sensitivity for assessing transplant eligibility based on MC when adopting the conventional radiological hallmarks of HCC. Our modified criteria showed significantly better sensitivity and accuracy than the conventional radiological hallmarks.