This article reviews three pediatric-onset liver diseases: Fontan-associated liver disease (FALD), liver cirrhosis caused by biliary atresia, and MASLD/MASH associated with hypopituitarism. All of these conditions carry a high risk of progression to liver fibrosis and cirrhosis, and require multidisciplinary collaborative treatment and long-term follow-up from childhood into adulthood. FALD is mainly caused by chronically elevated central venous pressure in the Fontan circulation, with imaging required for assessment of hepatic fibrosis and nodules. In biliary atresia, hepatic fibrosis often progresses even after a Kasai operation, with complications such as cholangitis, hepatolithiasis, and portal hypertension. Hypopituitarism predisposes a patient to MASLD/MASH, which may advance to cirrhosis, particularly due to reduced GH and IGF-1. MRI techniques, especially PDFF, are promising for noninvasive quantification of hepatic steatosis.

This review focuses on imaging evaluation of pediatric surgical liver diseases, including tumors, trauma, and vascular/portal venous anomalies. Liver tumors require comprehensive assessment using ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI), in conjunction with age and alpha-fetoprotein (AFP) level. For hepatoblastoma and pediatric hepatocellular carcinoma, staging and treatment planning are based on the PRETEXT classification. In hepatic injury, initial evaluation with focused assessment with sonography for trauma (FAST) and contrast-enhanced CT is required for determining the severity, while the PECARN rule is recommended to avoid unnecessary CT scans. For hepatic vascular and portal venous anomalies, accurate diagnosis of congenital portosystemic shunt, extrahepatic portal vein obstruction, and patent ductus venosus is critical. Imaging modalities such as US, CT, MRI, and angiography play a key role in guiding therapeutic decision-making.

Pediatric liver transplantation is an important treatment for children with end-stage liver disease. In Japan, pediatric liver transplantation has primarily advanced through use of living donor grafts. The enactment of the Organ Transplant Law in 1997 permitted organ donation after brain death, and a subsequent revision in July 2010 extended this to include donors under the age of 15. Diagnostic imaging is vital for all stages of transplantation, including brain death determination, recipient evaluation before and after surgery, and living donor assessment. The indications for pediatric liver transplantation are diverse, but biliary atresia is the most common. It is crucial to perform appropriate imaging studies based on a thorough understanding of the liver diseases indicated for transplantation, as well as the vascular and biliary anatomy necessary for the surgical procedure. This paper reviews the primary liver diseases indicated for transplantation and the knowledge required for preoperative evaluation of both recipients and living donors.

Pediatric biliary disorders are uncommon but clinically significant conditions in routine practice. Among these disorders, biliary atresia and congenital biliary dilatation with pancreaticobiliary maljunction are highly dependent on imaging for diagnosis, and a timely, accurate diagnosis is crucial for a favorable prognosis. This review synthesizes the key ultrasonographic features of biliary atresia and provides practical insights into differential diagnosis and postoperative surveillance. We also outline the characteristic imaging findings and complications of congenital biliary dilatation with pancreaticobiliary maljunction. Pediatric pancreatic tumors are rare and pose diagnostic challenges. Solid pseudopapillary neoplasm is the most common of these tumors, and therefore, we focus on imaging evaluation of this disease. Advances in imaging technology and accumulating clinical experience continue to refine the pathophysiologic understanding and diagnostic approach to this condition. In this review, we summarize the current state of pediatric biliary disorders and pancreatic tumors based on the latest evidence.

Various imaging modalities are used in the evaluation of pediatric gastrointestinal diseases, including plain radiography, ultrasonography, CT and MRI, gastrointestinal contrast studies, endoscopy, and nuclear medicine. Selection of an appropriate imaging technique should take into account the specific disease, the child’s age, radiation exposure, and the necessity of the examination. Among the imaging methods, ultrasonography is a highly versatile modality that can be performed across all pediatric age groups and provides real-time diagnostic information. Understanding the characteristic imaging findings of common pediatric gastrointestinal disorders and utilizing appropriate imaging techniques can greatly support future clinical practice.

Congenital esophageal atresia is characterized by disappearance of fetal gastric bubbles, polyhydramnios, and a pouch sign indicating an enlarged upper esophagus. After birth, distinguishing between Type A and Type C based on the presence or absence of air in the abdomen on X-ray is crucial. Congenital intestinal atresia is characterized by features such as the double bubble sign or triple bubble sign. Complications like umbilical cord ulcers can cause intrauterine death, but prenatal imaging diagnosis remains challenging and is a significant problem. Diagnosis of Hirschsprung’s disease relies on postnatal clinical symptoms, but confirming the difference in caliber via barium enema is crucial for determining the extent of the lesion. In imperforate anus, visualization of the target sign prenatally is important diagnostically. After birth, determining the specific type of condition through contrast studies is vital. Preoperative MRI assessment of the sphincter muscle groups is required for design of an optimal surgical approach. Necrotizing enterocolitis is a severe condition that occurs frequently in extremely low birth weight infants. If it progresses, it can lead to intestinal necrosis and perforation, resulting in a high mortality rate. Imaging, confirmation of the presence of gas in the intestinal wall and portal vein is critical.

Sonography is the most appropriate modality for imaging the gastrointestinal tract in children. However, this is not well known to ordinary doctors. Sonography not only helps to diagnose intussusception, but also provides information on surgical and pathological findings. When performing an ultrasound examination of acute appendicitis, pathological changes can be directly depicted. Blood flow assessment of intestinal wall is also much more accurate than before. It is now possible to diagnose ischemia caused by midgut volvulus with malrotation before they become fatal. It is still difficult to understand intestinal obstruction in detail before surgery, but it is possible to proceed with surgery after obtaining more information about the degree of ischemia and the cause of intestinal obstruction.