Pediatric computed tomography practice in Japanese university hospitals from 2008-2010: did it differ from German practice?

Quantitative Analysis of the Clinical Reasons Influencing the Frequency of Pediatric Head CT Examinations: A Single-Center Observation Study

Epidemiological studies on radiation exposure from pediatric CT scans have attracted attention in terms of radiological protection. These studies have not taken into account the reasons why CT examinations were performed. It is presumed that there are clinical reasons that justify more frequent CT examinations in children. The purpose of this study was to characterize the clinical reasons why relatively high numbers of head CT examinations (NHCT) are frequently performed and to conduct a statistical analysis to determine the factors governing the NHCT. Patient information, the date of examination, and medical conditions for examination data stored on the radiology information system were used to investigate the reasons for undergoing CT examinations. The target facility was National Children's Hospital; data were obtained from March 2002 to April 2017, and the age of the study population was less than 16 years old. Quantitative analysis of the factors associated with frequent examinations was conducted by Poisson regression analysis. Among all patients who had a CT scan, 76.6% had head CT examinations, and 43.4% of children were under 1 year old at the time of the initial examination. There were marked differences in the number of examinations depending on the disease. The average NHCT was higher for children younger than 5 days of age. Among children less than 1 year of age with surgery, there was a marked difference between hydrocephalus, with a mean = 15.5 (95% CI 14.3,16.8), and trauma, with a mean = 8.3 (95% CI 7.2,9.4). In conclusion, this study revealed that NHCT was significantly higher in children who had undergone surgery than in those who had not been to the hospital. The clinical reasons behind patients with higher NHCT should be considered in investigating a causal relationship between CT exposure and brain tumors.

Clinical indications for the use of computed tomography in children who underwent frequent computed tomography: a near-13-year follow-up retrospective study at a single institution in Japan

Recent studies suggest a causal link of childhood leukemia and brain tumor with repeated computed tomography (CT) scans. The reasons why frequent CT scans are taken in a specific child remain unclear. The present study aimed to clarify the medical reasons why frequent CT examinations in children, and the characteristics of the diseases of those children that required multiple CT scans. A long-term follow-up retrospective study was conducted over a 12.75-year period at a single institution. Radiological reports were investigated that contained the indications for the CT scans. The clinical indications were classified for the examination of children under 16 years of age who underwent more than three CT scans into trauma, tumor, inflammation, and others. This study showed that 8.5% of CT examinations were done three times or more. The numbers of patients by indication were 23.3% for trauma, 5.3% for hydrocephalus, and 2.3% for appendicitis. The frequencies of trauma and inflammation decreased rapidly with an increasing number of CT scans. In particular, hydrocephalus brought high frequency more than ten scans. Regarding the frequencies of clinical indications by age groups, there was a significant difference (p<0.05). The near-13-year follow-up study indicated the main clinical indications for frequent CT scans in children were trauma and hydrocephalus. Multiple follow-up CT scans in children with hydrocephalus would be traded off against the resultant increase in brain tumor risk associated with CT exposure.

The present state of radiation exposure from pediatric CT examinations in Japan-what do we have to do?

The use of computed tomography (CT) has increased dramatically over the past several decades and has resulted in a concurrent increase in medical exposure to ionizing radiation. Several recent studies have examined the link between medical radiation and the risk of cancer, especially in children. The cancer risk associated medical exposure has not been definitively confirmed. However, we have to reduce unwarranted medical radiation exposure in pediatric patients. Justification and optimization are of great importance in order to minimize these risks, and the standardization of CT usage is essential. However, in Japan no clinical guidelines for the use of CT have been commonly agreed upon, especially in children. Furthermore, the CT-associated radiation exposure in Japan varies widely among the different facilities. Further studies based on a nationwide survey in Japan will be required in order to establish simple and useful clinical guidelines.

Medical conditions associated with the use of CT in children and young adults, Great Britain, 1995-2008

OBJECTIVE

To describe the medical conditions associated with the use of CT in children or young adults with no previous cancer diagnosis.

METHODS

Radiologist reports for scans performed in 1995-2008 in non-cancer patients less than 22 years of age were collected from the radiology information system in 44 hospitals of Great Britain. By semantic search, an automated procedure identified 185 medical conditions within the radiologist reports. Manual validation of a subsample by a paediatric radiologist showed a satisfactory performance of the automatic coding procedure.

RESULTS

Medical information was extracted for 37,807 scans; 19.5% scans were performed in children less than 5 years old; 52.0% scans were performed in 2000 or after. Trauma, diseases of the nervous (mainly hydrocephalus) or the circulatory system were each mentioned in 25-30% of scans. Hydrocephalus was mentioned in 19% of all scans, 59% of scans repeated ≥5 times in a year, and was the most frequent condition in children less than 5 years of age. Congenital diseases/malformations, disorders of the musculoskeletal system/connective tissues and infectious or respiratory diseases were each mentioned in 5-10% of scans. Suspicionor diagnosis of benign or malignant tumour was identified in 5% of scans.

CONCLUSION

This study describes the medical conditions that likely underlie the use of CT in children in Great Britain. It shows that patients with hydrocephalus may receive high cumulative radiation exposures from CT in early life, i.e. at ages when they are most sensitive to radiation. Advances in knowledge: The majority of scans were unrelated to cancer suspicion. Repeated scans over time were mainly associated with the management of hydrocephalus.