Utility of diffusion weighted imaging with the quantitative apparent diffusion coefficient in diagnosing residual or recurrent hepatocellular carcinoma after transarterial chemoembolization: a meta-analysis

Role of diffusion-weighted imaging in response prediction and evaluation after high dose rate brachytherapy in patients with colorectal liver metastases

BACKGROUND

The aim of the study was to assess the role of diffusion-weighted imaging (DWI) to evaluate treatment response in patients with liver metastases of colorectal cancer.

PATIENTS AND METHODS

In this retrospective, observational cohort study, we included 19 patients with 18 responding metastases (R-Mets; follow-up at least one year) and 11 non-responding metastases (NR-Mets; local tumor recurrence within one year) who were treated with high-dose-rate brachytherapy (HDR-BT) and underwent pre- and post-interventional MRI. DWI (qualitatively, mean apparent diffusion coefficient [ADCmean], ADCmin, intraindividual change of ADCmean and ADCmin) were evaluated and compared between pre-interventional MRI, first follow-up after 3 months and second follow-up at the time of the local tumor recurrence (in NR-Mets, mean: 284 ± 122 d) or after 12 months (in R-Mets, mean: 387+/-64 d). Sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs) for detection of local tumor recurrence were calculated on second follow up, evaluating (1) DWI images only, and (2) DWI with Gd-enhanced T1-weighted images on hepatobiliary phase (contrast-enhanced [CE] T1-weight [T1w] hepatobiliary phase [hb]).

RESULTS

ADCmean significantly increased 3 months after HDR-BT in both groups (R-Mets: 1.48 ± 0.44 and NR-Mets: 1.49 ± 0.19 x 10-3 mm2;/s, p < 0.0001 and p = 0.01), however, intraindividual change of ADCmean (175% vs.127%, p = 0.03) and ADCmin values (0.44 ± 0.24 to 0.82 ± 0.58 x 10-3 mm2/s) significantly increased only in R-Mets (p < 0.0001 and p < 0.001). ADCmin was significant higher in R-Mets compared to NR-Mets on first follow-up (p = 0.04). Sensitivity (1 vs. 0.72), specificity (0.94 vs. 0.72), PPV (0.91 vs. 0.61) and NPV (1 vs. 0.81) could be improved by combining DWI with CE T1w hb compared to DWI only.

CONCLUSIONS

DW-MRI seems to be helpful in the qualitative and quantitative evaluation of treatment response after HDR-BT of colorectal metastases in the liver.

Diffusion-weighted MRI (DWI) for assessment of response to high-dose-rate CT-guided brachytherapy (HDR-BT) of hepatocellular carcinoma

BACKGROUND

High-dose-rate computed tomography (CT)-guided brachytherapy (HDR-BT) has shown promising results in patients with hepatocellular carcinoma (HCC). While growing evidence shows clear limitations of mRECIST, diffusion-weighted imaging (DWI) has relevant potential in improving the response assessment.

PURPOSE

To assess whether DWI allows evaluation of short- and long-term tumor response in patients with HCC after HDR-BT.

MATERIAL AND METHODS

A total of 22 patients with 11 non-responding HCCs (NR-HCC; local tumor recurrence within two years) and 24 responding HCCs (R-HCC; follow-up at least two years) were included in this retrospective bi-center study. HCCs were treated with HDR-BT and patients underwent pre- and post-interventional magnetic resonance imaging (MRI). Analyses of DWI were evaluated and compared between pre-interventional MRI, 1.follow-up after 3 months and 2.follow-up at the time of the local tumor recurrence (in NR-HCC) or after 12 months (in R-HCC).

RESULTS

ADCmean of R-HCC increased significantly after HDR-BT on the first and second follow-up (ADCmean: 0.87 ± 0.18 × 10-3 mm2/s [pre-interventional]: 1.14 ± 0.23 × 10-3 mm2/s [1. post-interventional]; 1.42 ± 0.32 × 10-3 mm2/s [2. post-interventional]; P < 0.001). ADCmean of NR-HCC did not show a significant increase from pre-intervention to 1. post-interventional MRI (ADCmean: 0.85 ± 0.24 × 10-3 mm2/s and 1.00 ± 0.30 × 10-3 mm2/s, respectively; P = 0.131). ADCmean increase was significant between pre-intervention and 2. follow-up (ADCmean: 1.03 ± 0.19 × 10-3 mm2/s; P = 0.018). There was no significant increase of ADCmean between the first and second follow-up. There was, however, a significant increase of ADCmin after 12 months (ADCmin: 0.87 ± 0.29 × 10-3 mm2/s) compared to pre-interventional MRI and first follow-up (P < 0.005) only in R-HCC.

CONCLUSION

The tumor response after CT-guided HDR-BT was associated with a significantly higher increase in ADCmean and ADCmin in short- and long-term follow-up.

Recent Advances in Locoregional Therapy of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is responsible for 90% of primary hepatic cancer cases, and its incidence with associated morbidity and mortality is growing worldwide. In recent decades, there has been a revolution in HCC treatment. There are three main types of locoregional therapy: radiofrequency ablation, transarterial chemoembolisation, and transarterial radioembolisation. This article summarises recent advances in locoregional methods.

Radiological findings in non-surgical recurrent hepatocellular carcinoma: From locoregional treatments to immunotherapy

Since hepatocellular carcinoma (HCC) represents an important cause of mortality and morbidity all over the world. Currently, it is fundamental not only to achieve a curative treatment but also to manage in the best way any possible recurrence. Even if the latest update of the Barcelona Clinic Liver Cancer guidelines for HCC treatment has introduced new locoregional techniques and confirmed others as well-established clinical practices, there is still no consensus about the treatment of recurrent HCC (RHCC). Locoregional treatments and medical therapy represent two of the most widely accepted approaches for disease control, especially in the advanced stage of liver disease. Different medical treatments are now approved, and others are under investigation. On this basis, radiology plays a central role in the diagnosis of RHCC and the assessment of response to locoregional treatments and medical therapy for RHCC. This review summarized the actual clinical practice by underlining the importance of the radiological approach both in the diagnosis and treatment of RHCC.

Current status and prospect of treatments for recurrent hepatocellular carcinoma

Owing to its heterogeneous and highly aggressive nature, hepatocellular carcinoma (HCC) has a high recurrence rate, which is a non-negligible problem despite the increasing number of available treatment options. Recent clinical trials have attempted to reduce the recurrence and develop innovative treatment options for patients with recurrent HCC. In the event of liver remnant recurrence, the currently available treatment options include repeat hepatectomy, salvage liver transplantation, tumor ablation, transcatheter arterial chemoembolization, stereotactic body radiotherapy, systemic therapies, and combination therapy. In this review, we summarize the strategies to reduce the recurrence of high-risk tumors and aggressive therapies for recurrent HCC. Additionally, we discuss methods to prevent HCC recurrence and prognostic models constructed based on predictors of recurrence to develop an appropriate surveillance program.

Current Imaging Diagnosis of Hepatocellular Carcinoma

Simple Summary

The role of imaging in the management of hepatocellular carcinoma (HCC) has significantly evolved and expanded beyond the plain radiological confirmation of the tumor based on the typical appearance in a multiphase contrast-enhanced CT or MRI examination. The introduction of hepatobiliary contrast agents has enabled the diagnosis of hepatocarcinogenesis at earlier stages, while the application of ultrasound contrast agents has drastically upgraded the role of ultrasound in the diagnostic algorithms. Newer quantitative techniques assessing blood perfusion on CT and MRI not only allow earlier diagnosis and confident differentiation from other lesions, but they also provide biomarkers for the evaluation of treatment response. As distinct HCC subtypes are identified, their correlation with specific imaging features holds great promise for estimating tumor aggressiveness and prognosis. This review presents the current role of imaging and underlines its critical role in the successful management of patients with HCC.

Abstract

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer related death worldwide. Radiology has traditionally played a central role in HCC management, ranging from screening of high-risk patients to non-invasive diagnosis, as well as the evaluation of treatment response and post-treatment follow-up. From liver ultrasonography with or without contrast to dynamic multiple phased CT and dynamic MRI with diffusion protocols, great progress has been achieved in the last decade. Throughout the last few years, pathological, biological, genetic, and immune-chemical analyses have revealed several tumoral subtypes with diverse biological behavior, highlighting the need for the re-evaluation of established radiological methods. Considering these changes, novel methods that provide functional and quantitative parameters in addition to morphological information are increasingly incorporated into modern diagnostic protocols for HCC. In this way, differential diagnosis became even more challenging throughout the last few years. Use of liver specific contrast agents, as well as CT/MRI perfusion techniques, seem to not only allow earlier detection and more accurate characterization of HCC lesions, but also make it possible to predict response to treatment and survival. Nevertheless, several limitations and technical considerations still exist. This review will describe and discuss all these imaging modalities and their advances in the imaging of HCC lesions in cirrhotic and non-cirrhotic livers. Sensitivity and specificity rates, method limitations, and technical considerations will be discussed.

MRI features of treated hepatocellular carcinoma following locoregional therapy: a pictorial review

Hepatocellular carcinoma (HCC) is a leading cause of cancer death worldwide and within the United States. Liver transplant or partial liver resection is the definitive treatment of choice for HCC; however, the majority of cases are detected in advanced stages due to its early-stage asymptomatic nature, often precluding surgical treatment. Locoregional therapy plays an essential role in HCC management, including curative intent, as a bridge to transplant, or in some cases palliative therapy. Radiologists play a critical role in assessing tumor response following treatment to guide further management that may potentially impact transplantation eligibility; therefore, it is important for radiologists to have an understanding of different locoregional therapies and the variations of imaging response to different therapies. In this review article, we outline the imaging response to ablative therapy (AT), transarterial chemoembolization (TACE), selective internal radiation therapy (SIRT), and stereotactic body radiation therapy (SBRT). We will also briefly discuss the basic concepts of these locoregional therapies. This review focuses on the imaging features following locoregional treatment for hepatocellular carcinoma following AT, TACE, SIRT, and SBRT.

The Role of Non-Gaussian Models of Diffusion Weighted MRI in Hepatocellular Carcinoma: A Systematic Review

The importance of Diffusion Weighted Imaging (DWI) in hepatocellular carcinoma (HCC) has been widely handled in the literature. Due to the mono-exponential model limitations, several studies recently investigated the role of non-Gaussian DWI models in HCC. However, their results are variable and inconsistent. Therefore, the aim of this systematic review is to summarize current knowledge on non-Gaussian DWI techniques in HCC. A systematic search of the literature, including PubMed, Google Scholar, MEDLINE, and ScienceDirect databases, was performed to identify original articles since 2010 that evaluated the role of non-Gaussian DWI models for HCC diagnosis, grading, response to treatment, and prognosis. Studies were grouped and summarized according to the non-Gaussian DWI models investigated. We focused on the most used non-Gaussian DWI models (Intravoxel Incoherent Motion (IVIM), Diffusion Kurtosis Imaging (DKI), and Stretched Exponential—SE). The quality of included studies was evaluated by using QUADAS-2 and QUIPS tools. Forty-three articles were included, with IVIM and DKI being the most investigated models. Although the role of non-Gaussian DWI models in clinical settings has not fully been established, our findings showed that their parameters may potentially play a role in HCC. Further studies are required to identify a standardized DWI acquisition protocol for HCC diagnosis, grading, response to treatment, and prognosis.

Value of Gd-EOB-DTPA-Enhanced MRI and Diffusion-Weighted Imaging in Detecting Residual Hepatocellular Carcinoma After Drug-Eluting Bead Transarterial Chemoembolization

RATIONALE AND OBJECTIVES

To investigate the value of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) in diagnosing residual hepatocellular carcinoma (HCC) after drug-eluting bead transarterial chemoembolization (DEB-TACE).

MATERIALS AND METHODS

Sixty-two patients (50 men, 12 women; mean age, 56.8 ± 1.4 years) with 74 HCCs who underwent Gd-EOB-DTPA-enhanced MRI and DWI in 1-2-month intervals after DEB-TACE were retrospectively studied. Imaging features derived from Gd-EOB-DTPA-enhanced MRI and DWI were analyzed and compared between residual HCCs and necrotic tumors. The sensitivity and specificity of Gd-EOB-DTPA-enhanced MRI and DWI with quantitative apparent diffusion coefficient (ADC) values in diagnosing residual HCCs were calculated and compared, based on the reference standard of pathology and/or angiography.

RESULTS

Thirty-three residual HCCs and 41 necrotic tumors were diagnosed. Residual HCCs presented characteristics of arterial hypervascularity (90.91%) and DWI hyperintensity (78.78%), which were of importance in differentiating necrotic tumors (p< 0.05). DWI showed lower sensitivity (78.79% vs. 96.97%, p< 0.001) and specificity (78.05% vs. 100%, p< 0.001) than Gd-EOB-DTPA-enhanced MRI in diagnosing residual HCCs after DEB-TACE. Residual HCCs had a significantly higher mean ADC value than necrotic tumors (1.30 ± 0.32 × 10^-3 mm²/s vs. 1.55 ± 0.50 × 10^-3 mm²/s, p< 0.001). Receiver operating characteristic curve analysis for identifying residual HCCs demonstrated that the threshold ADC value of 1.25 × 10^-3 mm²/s had 84.85% sensitivity and 87.80% specificity.

CONCLUSION

Gd-EOB-DTPA-enhanced MRI is superior to DWI in diagnosing residual HCCs after DEB-TACE, and arterial hypervascularity and DWI hyperintensity are important imaging features in distinguishing residual HCCs from necrotic tumors.

Quantitative magnetic resonance imaging for focal liver lesions: bridging the gap between research and clinical practice

Magnetic resonance imaging (MRI) is highly important for the detection, characterization, and follow-up of focal liver lesions. Several quantitative MRI-based methods have been proposed in addition to qualitative imaging interpretation to improve the diagnostic work-up and prognostics in patients with focal liver lesions. This includes DWI with apparent diffusion coefficient measurements, intravoxel incoherent motion, perfusion imaging, MR elastography, and radiomics. Multiple research studies have reported promising results with quantitative MRI methods in various clinical settings. Nevertheless, applications in everyday clinical practice are limited. This review describes the basic principles of quantitative MRI-based techniques and discusses the main current applications and limitations for the assessment of focal liver lesions.