Practical use and pitfalls of hepatocyte-specific contrast agents (HSCAs) for pediatric hepatic and biliary magnetic resonance imaging

Hepatic benign and malignant masses in children: a single UK tertiary centre experience

PURPOSE

The aim of this study was to review the incidence, spectrum and investigation of liver masses presenting to our tertiary liver unit.

METHODS

A retrospective single-centre cohort study of paediatric patients (age < 16 years) diagnosed with a liver mass who were investigated at a UK paediatric hepatobiliary tertiary referral centre. Data relating to the clinical findings at presentation, source of referral, diagnostic investigations and histopathology findings were recorded and analysed.

RESULTS

107 patients were identified between July 2012 and July 2019 (55 females). 69 (64%) patients had benign liver lesions, whereas the remaining 38 (36%) were found to have malignant masses. The liver lesions were most commonly detected incidentally (33%) with the second most common presentation being with palpable mass (29%). 82 (77%) patients were referred from other hospitals. All patients underwent USS, 74% MRI, 36% CT, 5% CEUS, 1% PET and 5% HIDA scan with 47% ultimately undergoing biopsy. 72% of patients had AFP measured. The most common benign liver masses were haemangioma 33 (48%), hepatic cyst 17 (25%) and FNH 12 (19%). Amongst the malignant lesions, 29 (76%) were hepatoblastoma and 3 (8%) were hepatocellular carcinoma.

CONCLUSIONS

This large review series demonstrates that just over 1/3 of patients presenting to a paediatric tertiary referral centre with a focal liver lesion had neoplastic liver lesions, despite the published literature commonly stating that 2/3 of paediatric liver masses are malignant.

Liver Tumours in Children: The Hepatologist's View

ABSTRACT

Diagnostic and therapeutic innovations have changed the way we now approach liver tumours in children and adolescents. Novel imaging tools, increasing awareness, and surveillance has led to early diagnosis of benign and malignant liver tumours. Multidisciplinary interventions have favourably altered the natural course in some liver tumours. The role of liver transplantation is expanding and has become fully integrated into today's therapeutic algorithms. Transarterial locoregional and ablation therapies have been successful in adults and are being explored in children to facilitate resectability and improve outcome. For the first time, North American, Japanese, and European experts have designed a global trial to optimize management of malignant liver tumours and aim to find signature molecular profiles that will translate to individualised treatment strategies.This article aims to offer an overview of recent advances in our understanding of liver tumours in children. It focuses on the paediatric hepatologist's view and their role in the multidisciplinary management of benign and malignant liver tumours.

Rate of gadoxetate disodium (Eovist®) induced transient respiratory motion in children and young adults

BACKGROUND

Gadoxetate disodium (Eovist®, Bayer Healthcare, Wayne, NJ) is the preferred MR contrast agent for pediatric hepatobiliary imaging. A known limitation of this contrast agent is transient severe respiratory artifacts during arterial phase imaging, and some adult studies have raised caution against its use for evaluation of arterial enhancing lesions. The reported rate of transient severe breathing motion is 5-22% in adult studies. This study seeks to evaluate the frequency of transient severe respiratory motion secondary to gadoxetate disodium in a pediatric cohort.

MATERIALS AND METHODS

This is a retrospective, IRB-approved study with informed consent waiver. The radiology information system of a children's hospital was searched to identify all MRI studies performed with gadoxetate disodium during January 2016-June 2018. Two readers independently evaluated all phases of a dynamic liver protocol for respiratory motion artifact on a 5-point scale (1 none, 2 mild, 3 moderate, 4 severe-still diagnostic, 5 extreme-not diagnostic). Average scores of the 2 readers for each phase were used for analyses. Transient severe respiratory motion was defined as an increase in artifact score of ≥ 1.5 from pre-contrast to arterial phase that returned to < 3 in equilibrium phase of imaging.

RESULTS

The study cohort consisted of 140 cases (60% female), age range: 1 month-23 years (median 13 years). 102/140 scans were performed non-sedated. Mean respiratory motion score for each phase of scan for the entire cohort were pre-contrast: 2.23, arterial: 2.56, portal venous: 2.39, and equilibrium: 2.31. Transient severe respiratory motion was seen in 8 non-sedated cases and in 0 sedated cases. The rate of transient severe respiratory motion in a non-sedated pediatric cohort was estimated at 7.84% (8/102 cases).

CONCLUSION

The rate of transient severe respiratory motion in the non-sedated pediatric population is in the lower end of the range reported in adults. Transient severe respiratory motion is not observed in sedated patients.

Intravenous gadolinium-based hepatocyte-specific contrast agents (HSCAs) for contrast-enhanced liver magnetic resonance imaging in pediatric patients: what the radiologist should know

Hepatocyte-specific contrast agents (HSCAs) are a group of intravenous gadolinium-based MRI contrast agents that can be used to characterize hepatobiliary pathology. The mechanism by which these agents are taken up by hepatocytes and partially excreted into the biliary tree improves characterization of hepatic lesions and biliary abnormalities relative to conventional extracellular gadolinium-based contrast agents (GBCAs). This manuscript presents an overview of HSCA use in pediatric patients with the intent to provide radiologists a guide for clinical use. We review available HSCAs and discuss dosing and age specifications for use in children. We also review various hepatic and biliary indications for HSCA use in children, with emphasis on the imaging characteristics distinct to HSCAs, as well as discussion of pitfalls one can encounter when imaging with HSCAs. Given the growing concern regarding gadolinium deposition in soft tissues and brain, we also discuss safety of HSCA use in children.

Use of Eovist in Pediatric Patients: Pearls and Pitfalls

Magnetic resonance imaging is excellent at characterizing pediatric hepatobiliary pathology. Noncontrast MRI is helpful due to T2 hyperintensity associated with bile, but contrast enhancement offers additional means of lesional characterization. In particular, hepatocyte-specific contrast agents such as gadoxetate disodium (Eovist) exhibit partial hepatobiliary excretion which may be leveraged in these contexts. In this review, we will discuss gadoxetate disodium usage, including a sample-imaging protocol, and demonstrate applications and limitations in the pediatric population.