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

Contrast enhanced ultrasound of liver lesions in patients treated for childhood malignancies

BACKGROUND

Patients treated for cancer have a higher incidence of focal liver lesions than the general population and there is often concern for a malignant etiology. This can result in patient, caregiver and physician anxiety and is managed by a "wait and watch" approach, or immediate additional imaging, or biopsy, depending on the degree of clinical concern. Because it is a low-cost, easily accessible, radiation and sedation free modality, we investigated the value of contrast enhanced ultrasound (CEUS) to accurately distinguish benign from malignant liver lesions in patients treated for childhood malignancies.

METHODS

We performed an IRB approved retrospective study of 68 subjects who were newly diagnosed, on treatment or off treatment for a pediatric malignancy and had liver lesions discovered on CT, MRI or non-contrast ultrasound and subsequently underwent CEUS between September 2013 and September 2021. Two experienced pediatric radiologists and a radiology trainee, blinded to the etiology of the liver lesions, independently reviewed the CEUS examinations and categorized lesions as benign, indeterminate, or malignant. The reference standard was biopsy for 19 lesions and clinical follow-up for 49. The sensitivity, specificity, positive and negative predictive value, and diagnostic accuracy of CEUS were calculated using only the benign and malignant CEUS classifications. Inter-reviewer agreement was assessed by Cohen's kappa statistic.

RESULTS

There were 26 males and 42 females, mean age, 14.9 years (range, 1-52 years). Fifty subjects were off therapy, twelve receiving treatment, and six with newly diagnosed cancer. By the reference standard, 59 (87%) lesions were benign and 9 (13%) were malignant. Sensitivities of CEUS for the three reviewers ranged from 83 to 100% (95% CI, 35.9-100%), specificities from 93.1 to 96.0% (95% CI, 83.5-99.6%), PPV 60.0-71.4% (95% CI, 29.0-96.3%), NPV 98.0-100% (95% CI, 89.2-100%) and accuracy from 93.8 to 94.6% (95% CI, 85.1-99.7%). The kappa statistic for agreement between the two experienced radiologists was moderate at 0.58.

CONCLUSIONS

CEUS is highly accurate in distinguishing benign from malignant etiologies of liver lesions in patients treated for pediatric malignancies.

Evaluation and management of biliary complications after pediatric liver transplantation: pearls and pitfalls for percutaneous techniques

In pediatric liver transplantation, bile duct complications occur with a greater incidence than vascular anastomotic dysfunction and represent a major source of morbidity and mortality. While surgical re-anastomosis can reduce the need for retransplantation, interventional radiology offers minimally invasive and graft-saving therapies. The combination of small patient size and prevailing Roux-en-Y biliary enteric anastomotic techniques makes endoscopic retrograde cholangiopancreatography difficult if not impossible. Expertise in percutaneous management is therefore imperative. This article describes post-surgical anatomy, pathophysiology and noninvasive imaging of biliary complications. We review percutaneous techniques, focusing heavily on biliary access and interventions for reduced liver grafts. Subsequently we review the results and adverse events of these procedures and describe conditions that masquerade as biliary obstruction.

Pediatric biliary disorders: Multimodality imaging evaluation with clinicopathologic correlation

The spectrum of pathologies affecting the biliary tree in the pediatric population varies depending on the age of presentation. While in utero insults can result in an array of anatomic variants and congenital anomalies in newborns, diverse acquired biliary pathologies are observed in older children. These acquired pathologies display different presentations and consequences than adults. Multimodality imaging assessment of the pediatric biliary system is requisite to establishing an appropriate management plan. Awareness of the imaging features of the various biliary pathologies and conveying clinically actionable information is essential to facilitate appropriate patient management. In this paper, we will illustrate the anatomy and embryology of the pediatric biliary system. Then, we will provide an overview of the imaging modalities used to assess the biliary system. Finally, we will review the unique features of the pediatric biliary pathologies, complemented by histopathologic correlation and discussions of clinical management.

Mesenchymal hamartoma and undifferentiated embryonal sarcoma: diagnostic keys that radiologists need to know

OBJECTIVE

Hepatic tumors are uncommon in pediatric patients. Among the most common of these uncommon tumors are mesenchymal hamartoma and undifferentiated embryonal sarcoma, which have different origins but similar appearance on imaging studies. This paper reviews the characteristic findings and differential diagnosis of these entities. Ultrasonography is the first-line imaging test to study these tumors. Magnetic resonance imaging and computed tomography are useful for further characterizing the tumors and planning surgery.

CONCLUSION

Radiologists need to be familiar with the imaging findings of the different disease entities and to evaluate them together with the patient's age, personal history, and bloodwork.