Although the child population in Japan is declining, the number of child abuse notifications is increasing year by year. Child abuse cannot be ignored at medical institutions, and appropriate measures are required. Many cases of child abuse that visit medical institutions are suspected of child abuse based on the “main complaint”, “interview”, and “physical examination” in the outpatient department, and then further tests are conducted. One of them is Skeletal survey by plain X-ray. Skeletal survey is recommended mainly when there is a possibility of abuse under the age of 2 years, and further fractures may be found. If new findings are added, it will greatly affect the subsequent policy and thus can be said to be one of the most important tests. Abusive Head Trauma (AHT) is one condition that must not be overlooked. And symptoms at mild times such as vomiting, moodiness, poor feeding and others are non-specific, and are often difficult to distinguish from disease. Therefore, in daily medical care, they should always be discriminated so as not to overlook child abuse such as AHT.

Abusive head trauma (AHT) in infants and young children are broadly defined as those sustaining perpetrator-inflicted injury of the skull and intracranial contents. Shaken-baby syndrome is a subtype of AHT. The clinical findings might include neurologic signs and symptoms such as irritability, seizures, apnea, vomiting, and poor feeding. The characteristic imaging features of AHT include subdural hematoma, brain parenchymal injury, and retinal hemorrhages. Moreover, young infants are at an increased risk of upper cervical spinal injury such as soft-tissue or ligamentous ones. Therefore, head non-contrast head computed tomography (CT) and magnetic resonance imaging (MRI) including cervical the spine are necessary to diagnose AHT. Non-contrast head CT is the first diagnostic imaging modality for pediatric patients with symptoms. Initial head CT should include 3D reconstruction for the accurate representation of skull fractures. Thereafter, additional complementary MRI is more sensitive for intracranial hemorrhages and parenchymal injuries.

The focus of this article is to review the diagnostic findings of AHT and the optimal diagnostic imaging strategy for it.

Fractures are common injuries in physical abuse. Though skeletal survey is an important tool for the diagnosis of fractures, it is often performed in an inappropriate way. In this report, we show an example of the protocol of skeletal survey. Most fractures reported in abuse occur in young children, especially <12 months of age. So skeletal survey should be performed in children younger than 2 years with suspected abuse, and follow-up survey is important for children <12 month of age, because the acute fractures of infants are difficult to diagnosis. Follow-up survey can reveal the fractures in the healing phase.

Some fractures are specific for physical abuse, for example, classic metaphyseal lesions (CMLs) and rib fractures in infants. But the rib fractures are often missed, and so we should consider using chest CT in strongly suspected abuse. Finally, it is important to put the patient in a safe environment, and to obtain the most appropriate examinations for precise diagnosis.

Abdominal trauma is relatively infrequent among abuse, but may include intestinal perforation and damage to vital organs such as the liver and pancreas. In cases where potential organ injury cannot be ruled out, ultrasonography may be performed first to determine the presence of parenchymal organ damage or intestinal hematoma. Abdominal trauma due to abuse is common in children under the age of five years, a younger age than usually seen in traumatic abdominal trauma. Duodenal injury has not been reported in accidentally injured children under the age of four years, and duodenal trauma other than traffic accidents in children under the age of five years needs to be considered for abuse.

Some findings are specific to abuse in bone survey. On the other hand, for many abdominal injuries, it is difficult to specify the cause from only the imaging findings. It is considered important to comprehensively judge the image findings, clinical course, and blood test findings.

The medical diagnosis of child maltreatment cannot be made simply on the basis of these signs alone. It should be a comprehensive decision, and the statements of the parents must also be viewed as objective data. In this diagnostic process, diagnostic imaging information is an extremely powerful source of information.

The medical/welfare response, which prioritizes “child safety” at the initial stage, and the judicial-criminal response to question “individual responsibility” at the final stage are quite different, but can be interconnected.

An imaging report has the same legal value as a medical record. To avoid the misinterpretation of a determination based on imaging findings alone, it should state something like, “Please consider the consistency with the clinical course of events”, and instead of speculative statements when it is difficult to comment, it should state something like, “The opinions of specialists need to be confirmed”.

Few hospitals still have radiologists formally participating as members of the hospital child protection team. Radiologists, who can maintain an objective distance from parents, are in a position to exert a pivotal role. Pediatricians have high hopes for them.

Background: Vascular rings are congenital vascular anomalies that encircle and compress the trachea and esophagus. They have been increasingly detected by prenatal sonography in recent years. However, it is sometimes difficult to detect them accurately. We review the diagnostic imaging, clinical outcomes and management of our experience with vascular rings.

Methods: Four patients with vascular rings were identified by prenatal sonography, and enhanced-computed tomography (CT) was used for further investigation after their birth. We retrospectively studied these 4 cases.

Results: One patient was diagnosed with a right aortic arch, left brachiocephalic artery and left ductus arteriosus (RAA·LBCA·LDA), and the others were diagnosed with a right aortic arch, aberrant left subclavian artery and left ductus arteriosus (RAA·ALSA·LDA) by prenatal sonography. All patients were asymptomatic in the neonatal period. The patient with RAA·LBCA·LDA and one of the patients with RAA·ALSA·LDA had episodes of stridor associated with viral infection at the age of 1 month and 4 months, respectively. Enhanced-CT revealed a double aortic arch in the patient with RAA·LBCA·LDA and Kommerell diverticulum in all the patients with RAA·ALSA·LDA. Two patients with symptoms underwent surgical treatment, and their symptoms improved.

Conclusion: Prenatal sonography is an effective screening method for vascular rings but evaluating vascular structures accurately can be difficult in some cases. In such cases, enhanced-CT can provide detailed information. In particular, enhanced-CT should be performed if the possibility of DAA cannot be excluded by prenatal sonography. Making a diagnosis of asymptomatic vascular rings by prenatal sonography can provide treatment early when they become symptomatic.

Anti-N-methyl-d-aspartate (NMDA) receptor encephalitis causes nonspecific symptoms such as fever and headache, which are followed by psychotic symptoms and involuntary movements. On brain magnetic resonance imaging (MRI), no specific findings are noted for almost half of the patients with NMDA encephalitis. Even if MRI abnormalities are present, they may be discreet and reversible. A 10-year-old girl complained of dizziness and headache. She displayed psychotic symptoms and involuntary movements about 60 days after the onset of nonspecific symptoms, and autonomic symptoms 80 days later. MRI-FLAIR images showed high intensity signals distributed in the right hippocampus, insular cortex, amygdala and left hypothalamus. Anti-NMDA receptor encephalitis was diagnosed by detecting anti-NMDA receptor antibodies in the cerebrospinal fluid. Anti-NMDA receptor encephalitis is difficult to diagnose if one only relies on signs and symptoms or on MRI scans. Specific conditions such as psychosis as well as MRI findings in the temporal lobe are clues to diagnose anti-NMDA receptor encephalitis.

Fidget spinners, handheld toys designed to spin freely in one’s grasp, have become an entertainment source for consumers of all ages, especially school-age children. Fidget spinner component ingestion is frequent and requires endoscopic intervention at a higher rate than other foreign body ingestion. Toy construction may be inadequate to prevent fidget spinner fracture or disassembly and subsequent toy component ingestion in children. The majority of the fidget spinner components are identified radiographically. Radiographs may identify the foreign body location and complications, such as obstruction or perforation. Radiolucent components cannot be radiographically identified. Damage can occur if a button battery is in the esophagus. We report two patients with fidget spinner component ingestion to describe patient presentations and radiographic appearance. Both the patients were radiographically identified. One patient underwent endoscopy one month after fidget spinner component ingestion. Clinicians and radiologists should consider fidget spinners as one of the many varieties of toy that have a potential for ingestion or aspiration.

A patient with Kawasaki disease who had been treated with steroids was unable to walk because of pain in the hip and knee joints immediately after their discontinuation. An MRI examination revealed the presence of inflammation in both hip joints, no necrosis of the femoral head, and a low possibility of purulent hip arthritis. Thus, steroid treatment was safely resumed. The joint symptoms were promptly alleviated thereafter. A second MRI examination performed 6 months after the initial discontinuation of the steroid drug showed an improvement in the arthritis and the absence of chronic inflammatory diseases such as juvenile idiopathic arthritis. The arthritis in this case was determined to be a concomitant manifestation of Kawasaki disease. Acute and convalescent MRI examinations are useful for diagnosing the cause of arthritis in patients with Kawasaki disease and for determining the optimal treatment strategy.

Acute flaccid myelitis (AFM) associated with an enterovirus-D68 (EV-D68) outbreak occurred in Japan in the fall of 2015.

We report the case of a 4-year-old boy with acute flaccid paralysis (AFP) predominant in the right upper limb following fever and gastrointestinal symptoms. Early MRI studies showed cervical spinal cord swelling and longitudinal hyperintensity cord lesion on T2-weighted sagittal images, and AFM was listed in the differential diagnosis. EV-D68 was detected in the nasopharynx, and AFM caused by EV-D68 was diagnosed based on the clinical symptoms, clinical course, and examination findings. Intravenous immunoglobulin and methylprednisolone pulse therapy were not effective for the paralysis. Whole spinal contrast-enhanced MRI showed improvement of high-signal intensity lesions, but paralysis clinically progressed in the left upper limb, both lower limbs, trunk, and phrenic nerve. Physical therapy enabled him to walk and raise his left shoulder, but the right upper limb paralysis persisted.

AFM is important as a differential diagnosis presenting with AFP. Cranial and whole spinal MR imaging findings are useful to diagnose AFM.

Reversible cerebral vasoconstriction syndrome (RCVS) presents neurologically with reversible segmental vasospasms and is characterized primarily by complaints of sudden, severe (‘thunderclap’) headaches. Although disease prognosis is often good, some reports have described poorer outcomes in patients with comorbid stroke or other cerebrovascular injury. Here, we report a pediatric case of RCVS complicated by stroke resulting in lasting neurological sequelae.

A 13-year-old boy suddenly developed severe headaches, vomiting, disordered articulation, and left-sided arm and leg paralysis. Cranial magnetic resonance imaging revealed a cerebral infarction spanning the right globus pallidus to the corona radiata. Cranial magnetic resonance angiography indicated multifocal vascular wall irregularities and stenosis. Cerebral angiography indicated multi-segmental vasoconstriction. RCVS was diagnosed from these findings and clinical course; both improved upon oral verapamil administration, but the patient still experienced left arm rigidity and sensory paralysis.

We examined previously reported cases of RCVS complicated with cerebral infarction; pediatric cases were more likely to be male and to develop multifocal infarctions.

RCVS should be considered in the differential diagnosis of pediatric patients complaining of sudden, severe headaches. Furthermore, clinicians should continue to perform imaging exams regularly while observing patient symptoms and neurological findings.

Case 1: A 12-year-old girl consulted our orthopedics department with a chief complaint of a bulge in her proximal left upper arm. X-ray and MRI showed an osteochondroma of the proximal humerus. Repeated X-rays were obtained at 8-month follow up and showed near complete regression of the lesion. Case 2: A 16-year-old boy presented with painful swelling of the left distal thigh. He was diagnosed with osteochondroma by X-ray. MRI showed inflammation around the tumor. He was followed up with conservative treatment. By one year later, the tumor had regressed.

Osteochondromas are the most common benign tumors of bone. Most are discovered at 5–15 years of age. Because many osteochondromas are completely asymptomatic and unrecognized, their true incidence is unknown and the natural history is poorly understood. Their growth usually parallels that of the patient and usually ceases when skeletal maturity is reached. There are some reports about spontaneous regression of osteochondroma and its spontaneous regression is considered a rare phenomenon so far. However, spontaneous regression of osteochondroma may not be a rare phenomenon in childhood and adolescence.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a type of ANCA-associated vasculitis that is rare in children. We report the case of a 13-year-old girl who developed bronchial asthma one year prior to admission. She complained of fever, wheezing, and pain in both legs that lasted for a week. The peripheral blood eosinophil count was significantly increased (14,692/μl). Chest radiography and computed tomography (CT) findings consisted of patchy ground-glass opacities and infiltrates and pericardial effusion. Based on these findings, EGPA was strongly suspected. Prednisolone therapy was initiated, and her respiratory condition improved. The peripheral blood eosinophil count normalized on the 10th day of treatment. Echocardiography also showed pericardial effusion and hypokinesis, suggestive of pericarditis, which improved with treatment. The abnormalities on chest radiography improved gradually over time after initiating the treatment. The typical findings of EGPA on chest radiography and CT include diverse, migratory non-segmental multiple infiltrates, and ground-glass opacities, which were also observed in this case. The symptoms improved as treatment proceeded and almost disappeared after 2 weeks.

These findings of chest radiology and CT are not specific to EGPA, but help to examine complications and confirm the effect of treatment.