In general, pediatric facilities often experience difficulty handling adult hospitalizations, examinations, and surgeries due to their history and characteristics. In pediatric living-donor liver transplantation requiring an adult donor, "ingenuity" in terms of hardware and software is required in pediatric facilities. Most pediatric liver transplants in Japan are currently performed at university hospitals, and only three pediatric hospitals in Japan, including our own hospital, are performing liver transplantation. Until 2019, there were 11 facilities nationwide that had performed pediatric liver transplantation for more than 50 cases in the past and for 5 or more cases in the past 3 years. Nine of these were university hospitals, and the remaining two were pediatric hospitals, including our hospital. We started the first pediatric liver transplant program in Saitama Prefecture in September 2019, and donors were hospitalized and operated on at the adjacent Saitama Red Cross Hospital. A key characteristic of our hospital is that many incompatible living donor transplants are performed. As the pediatric cancer base hospital with the largest number of pediatric cancer registrations in Japan, pediatric solid tumor cases represented by hepatoblastoma, and other rare tumors are introduced to us. Professional and systematic cooperation between medical teams is very easy to maintain in pediatric facilities, but the management and cooperation of adult donors has been a problem. Our facility might provide a model case for liver transplantation in pediatric hospitals nationwide.

Interventional radiology procedures after pediatric liver transplantation include diagnostic liver biopsy (percutaneous transhepatic and percutaneous transjugular approaches), treatments for vascular and biliary complications, and percutaneous fluid drainage. Of these, Department of Radiology at National Center for Child Health and Development is deeply involved in treatments for vascular and biliary complications. Once interventional procedures are indicated, all patients are treated in collaborative work between transplant surgeons and radiologists. All procedures are managed under general anesthesia. The majority of interventional procedures are started with fluoroscopy-assisted ultrasound-guided percutaneous transhepatic puncture. Once percutaneous transhepatic access is accomplished, both vascular and biliary complications are managed with biplane fluoroscopic angiography equipment. We strongly recommend the use of lateral projection fluoroscopy, considering the anatomy of the transplanted liver. During the procedures, transhepatic puncture followed by sheath placement is performed by an experienced transplant surgeon. Subsequent interventional procedures are mainly performed by radiologists. This review demonstrates both typical and atypical cases necessitating technical modifications based on the clinician’s experience with interventional radiology procedures after liver transplantation.

Children are more susceptible to radiation exposure and have a longer life time than adults, making it necessary to avoid imaging examinations with radiation exposure as much as possible. If necessary, they should be performed with the minimum radiation dose while ensuring sufficient image quality required for diagnosis. It is the goal of the members of the Japan Pediatric Radiology Society to perform appropriate diagnostic imaging with high medical information value as gently as possible for all children. In this paper, the practical idea of justification for and optimization of pediatric diagnostic imaging are reviewed, and safety issues of pediatric sedation are discussed because sedation cannot be avoided in young children and intellectually impaired ones. In addition, MRI preparation videos are introduced, which are for Japanese children aiming to increase the number of them who can undergo noisy MRI examination without sedation.

I would like to discuss the proper use of contrast media in children. Proper use refers to a wide range of areas, but due to space limitations, this manuscript focuses on medical safety aspects such as judicial precedents and guidelines for complications of contrast media, and medical safety information.

Acute encephalopathy occurs in 500–800 persons/year, and is most common in infants aged 0 to 3 years. Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is the most common subtype, followed by clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS, 18%), and acute necrotizing encephalopathy (ANE, 3%). Although AESD is sometimes difficult to distinguish from febrile status epilepticus, the usefulness of high b-value diffusion-weighted images, arterial spin labeling (ASL), and MR spectroscopy has been reported. The bright tree appearance, characteristic of AESD, is considered to reflect the proliferation of gemistocytic astrocytes at the corticomedullary junction from the autopsy study. MERS is characterized by reduced reversible diffusion of the corpus callosum and has a good prognosis. It should be noted that acute focal bacterial pyelonephritis is often associated with MERS. WES analysis in patients with familial MERS reveals MYRF gene mutation, suggesting that the myelin sheath edema may be an underlying pathogenetic factor. Autoimmune GFAP astrocytopathy is characterized by symmetric lesions in the posterior thalamus and linear lesions in the lateral ventricles or corpus callosum.

Pediatric magnetic resonance imaging has been made difficult by the limited scan time available while keeping children still. However, recent MRI developments have enabled clinical application of advanced MRI technique for children. In this article, we describe such MRI sequences for pediatric neuroradiology.

The incidence of any particular skeletal dysplasia is thought to be low, but together all these diseases amount to approximately 1/1000, similar to Down syndrome. Recently, advanced diagnostic modalities such as CT scan, MRI, ultrasound and nuclear medicine play important roles in modern radiology. However, the usefulness of plain radiography has been unchanged for all skeletal dysplasias. In the first half of this review article, the author introduced the basic concepts of skeletal dysplasia, bone dysplasia family, and methodology of X-ray diagnosis. The second half of the article focused on particular radiological diagnosis of mucopolysaccharidoses (MPS) among skeletal dysplasias, especially the diagnosis of MPS-IV (Morquio syndrome). It is important to diagnose MPS-IV because a therapeutic drug has been established for this particular rare dysplasia.

We report a case of idiopathic chylopericardium diagnosed by lymphangiography using lipiodol during treatment of bacterial meningitis. A previously healthy 8-year-old boy developed bacterial meningitis at the age of 6 years 3 months, and echocardiography revealed pericardial effusion. He had a history of recurrent bacterial meningitis at 6 years and 7 months and 7 years and 9 months of age. The pericardial fluid volume often fluctuated during these episodes. Based on evaluation of the pericardial drainage fluid, he was diagnosed with chylopericardium prior to this admission. The patient was referred to our hospital to undergo lymphangiography (using lipiodol) to localize the leakage site(s). We performed echography guided percutaneous puncture of his right-sided inguinal lymph nodes, and lipiodol was injected. We observed leakage from the thoracic duct into the pericardial sac at the tracheal bifurcation level. Lymphangiography via the inguinal lymph nodes is a less invasive and useful approach that is increasingly being reported for direct imaging in children.