Recurrent hepatocellular carcinoma versus radiation-induced hepatic injury: differential diagnosis with MR imaging

Applications of T1 and T2 relaxation time calculation in tissue differentiation and cancer diagnostics-a systematic literature review

INTRODUCTION

The purpose of this review was to summarize current applications of non-contrast-enhanced quantitative magnetic resonance imaging (qMRI) in tissue differentiation, considering healthy tissues as well as comparisons of malignant and benign samples. The analysis concentrates mainly on the epithelium and epithelial breast tissue, especially breast cancer.

METHODS

A systematic review has been performed based on current recommendations by publishers and foundations. An exhaustive overview of currently used techniques and their potential in medical sciences was obtained by creating a search strategy and explicit inclusion and exclusion criteria.

RESULTS AND DISCUSSION

PubMed and Elsevier (Scopus & Science Direct) search was narrowed down to studies reporting T1 or T2 values of human tissues, resulting in 404 initial candidates, out of which roughly 20% were found relevant and fitting the review criteria. The nervous system, especially the brain, and connective tissue such as cartilage were the most frequently analyzed, while the breast remained one of the most uncommon subjects of studies. There was little agreement between published T1 or T2 values, and methodologies and experimental setups differed strongly. Few contemporary (after 2000) resources have been identified that were dedicated to studying the relaxation times of tissues and their diagnostic applications. Most publications concentrate on recommended diagnostic standards, for example, breast acquisition of T1- or T2-weighted images using gadolinium-based contrast agents. Not enough data is available yet to decide how repeatable or reliable analysis of relaxation times is in diagnostics, so it remains mainly a research topic. So far, qMRI might be recommended as a diagnostic help providing general insight into the nature of lesions (benign vs. malignant). However, additional means are generally necessary to differentiate between specific lesion types.

Indicator for local recurrence of hepatocellular carcinoma after proton beam therapy: analysis of attenuation difference between the irradiated tumor and liver parenchyma on contrast enhancement CT

OBJECTIVES

We aimed to identify dynamic CT features that can be used for prediction of local recurrence of hepatocellular carcinoma (HCC) after proton beam therapy (PBT).

METHODS

We retrospectively retrieved CT scans of patients with PBT-treated HCC, taken between January 2004 and December 2016. 17 recurrent lesions and 34 non-recurrent lesions were retrieved. The attenuation difference between irradiated tumor and irradiated parenchyma (AD_HCC-IP) was compared in the two groups by using the Mann-Whitney U test. Cut-off value of AD_HCC-IP was estimated by using the Youden index.

RESULTS

The follow-up time after PBT initiation ranged from 374 to 2402 days (median, 1069 days) in recurrent lesions, and 418 to 2923 days (median, 1091.5 days) in non-recurrent lesions (p = 0.892). The time until appearance of local recurrence after PBT initiation ranged from 189 to 2270 days (median, 497 days). AD_HCC-IP of recurrent lesions [mean, -21.8 Hounsfield units (HU); from -95 to -31 HU] was significantly greater than that of non-recurrent lesions (mean, -51.7 HU; from -117 to -12 HU) at 1-2 years in portal venous phase (p = 0.039). 5-year local tumor control rates were 0.93 and 0.56 in lesions with AD_HCC-IP at 1-2 years in PVP < -55 and ≥ -55 HU, respectively.

CONCLUSION

The attenuation difference between irradiated HCC and irradiated liver parenchyma in portal venous phase at 1-2 years after PBT can predict long-term local recurrence of HCC after treatment.

ADVANCES IN KNOWLEDGE

We identified a cut-off value for contrast enhancement of HCC after PBT that could predict future local recurrence.

Proton Beam Therapy for Hepatocellular Carcinoma: A Review of the University of Tsukuba Experience

Hepatocellular carcinoma (HCC) is the second most common cause of cancer-related death worldwide. Many treatment modalities were developed for HCC, including surgical resection, percutaneous ethanol injection, radiofrequency ablation, transarterial chemoembolization, liver transplantation, and sorafenib therapy. Our institution has shown that proton beam therapy (PBT) is also a safe, effective, and feasible treatment modality for HCC. The University of Tsukuba began to use PBT for HCC in 1983, and we have reported many findings during the past 3 decades. In this review, we will describe the history of PBT, our experience of using PBT for HCC, and its application based on tumor location, thrombosis, tumor size, and liver function.

Added value of diffusion-weighted MRI for evaluating viable tumor of hepatocellular carcinomas treated with radiotherapy in patients with chronic liver disease

OBJECTIVE

The purpose of this article is to evaluate the added value of diffusion-weighted imaging (DWI) to the diagnostic performance of conventional MRI in diagnosing viable hepatocellular carcinoma (HCC) tumors treated with radiotherapy in patients with chronic liver disease.

MATERIALS AND METHODS

Twenty-nine patients with viable tumor and 35 patients without viable tumor were enrolled. We assessed the signal intensity of viable tumor compared with irradiated liver on MRI and DWI. Signal intensity ratios and apparent diffusion coefficient (ADC) ratios of viable tumor to nonirradiated liver were also assessed on DWI with ADC maps. Two observers reviewed conventional MRI and combined MRI and DWI and rated them using a 5-point scale. Diagnostic performance was evaluated using a receiver operating characteristic (ROC) curve.

RESULTS

Viable tumors showed hyperintensity on T2-weighted and arterial phase images (16/29 [55.2%]) and hypointensity on portal (22/29 [75.9%]), 3-minute late (19/29 [65.5%]), and hepatobiliary phase (23/29 [79.3%]) images. Twenty-seven (93.1%) viable tumors showed hyperintensity on DWI and hypointensity on ADC maps. Mean signal intensity ratios and ADC ratios of viable tumor on DWI with ADC maps were significantly higher and lower than those of irradiated liver. Diagnostic performance (area under the ROC curve) improved significantly after adding DWI, and interobserver agreement was moderate for conventional MRI (κ = 0.450) and good after adding DWI (κ = 0.748).

CONCLUSION

Adding DWI to conventional MRI can improve the detection of viable HCC tumors treated with radiotherapy compared to conventional MRI alone.

Distinguishing post-treatment changes from recurrent disease in cholangiocarcinoma: a case report

Introduction

Three-dimensional techniques for radiotherapy have expanded possibilities for partial volume liver radiotherapy. Characteristic, transient radiographic changes can occur in the absence of clinical radiation-induced liver disease after hepatic radiotherapy and must be distinguished from local recurrence.

Case presentation

In this report, we describe computed tomography changes after chemoradiotherapy for cholangiocarcinoma as an example of collaboration to determine the clinical significance of the radiographic finding.

Conclusion

Because of improved three-dimensional, conformal radiotherapy techniques, consultation across disciplines may be necessary to interpret post-treatment imaging findings.

Progress in application of high-field-strength MR to diagnosis and treatment of hepatocellular carcinoma

Magnetic resonance imaging (MRI), a modern imaging modality, cannot only diagnose diseases, but also participate in their treatment. With the increase in static magnetic field strength, the features of high-field-strength MRI become increasingly predominant, thus MRI has been widely used in the diagnosis and treatment of diseases. MRI at high field strength can provide information on abnormal function and metabolism, monitor therapeutic procedures and reactions, and present excellent morphologic images for hepatocellular carcinoma.

Current awareness

In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of NMR in biomedicine. Each bibliography is divided into 9 sections: 1 Books, Reviews ' Symposia; 2 General; 3 Technology; 4 Brain and Nerves; 5 Neuropathology; 6 Cancer; 7 Cardiac, Vascular and Respiratory Systems; 8 Liver, Kidney and Other Organs; 9 Muscle and Orthopaedic. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted.