Radiation Exposure From Pediatric CT Scans and Subsequent Cancer Risk in the Netherlands

Estimation of organ-specific cancer and mortality risks associated with common indication-specific CT examinations of the abdominopelvic region

INTRODUCTION

There is a paucity of large-scale studies reporting organ doses and cancer risks in patients who undergo indication-specific CT examinations. This study estimated organ-specific lifetime attributable risk (LAR) of cancer incidence and mortality among patients who underwent indication-based computed tomography (CT) examinations [(involving abdominopelvic lesion, kidney stones and computed tomography-intravenous urography (CT-IVU)] in about 70% of the functioning CT facilities in Ghana.

METHODS

With a total of 1,100 data sets, organ doses were first determined using the National Cancer Institute Dosimetry System for CT (NCICTX) software version 2.1, and LAR values were predicted using the BEIR VII model.

RESULTS

The estimated radiation-induced colon cancer risks were likely in 39.4-59.8 out of 100,000 patients who underwent CT because of abdominopelvic lesion. The risk was even higher in CT-IVU examinations (53.3-66.4 patients in 100,000 procedures) but was relatively less (16.8-26.3 patients) in kidney stone procedures. Accordingly, the risk of radiation-induced colon mortality was more common in CT-IVU than in kidney stone procedures (22.7-28.2 versus 7.2-12.5 patients in 100,000 procedures).

CONCLUSION

These results call for further optimisation actions for indication-specific CT examinations to appropriately reduce the potential risk levels for patients' protection and safety.

AIGAN: Attention-encoding Integrated Generative Adversarial Network for the reconstruction of low-dose CT and low-dose PET images

X-ray computed tomography (CT) and positron emission tomography (PET) are two of the most commonly used medical imaging technologies for the evaluation of many diseases. Full-dose imaging for CT and PET ensures the image quality but usually raises concerns about the potential health risks of radiation exposure. The contradiction between reducing the radiation exposure and remaining diagnostic performance can be addressed effectively by reconstructing the low-dose CT (L-CT) and low-dose PET (L-PET) images to the same high-quality ones as full-dose (F-CT and F-PET). In this paper, we propose an Attention-encoding Integrated Generative Adversarial Network (AIGAN) to achieve efficient and universal full-dose reconstruction for L-CT and L-PET images. AIGAN consists of three modules: the cascade generator, the dual-scale discriminator and the multi-scale spatial fusion module (MSFM). A sequence of consecutive L-CT (L-PET) slices is first fed into the cascade generator that integrates with a generation-encoding-generation pipeline. The generator plays the zero-sum game with the dual-scale discriminator for two stages: the coarse and fine stages. In both stages, the generator generates the estimated F-CT (F-PET) images as like the original F-CT (F-PET) images as possible. After the fine stage, the estimated fine full-dose images are then fed into the MSFM, which fully explores the inter- and intra-slice structural information, to output the final generated full-dose images. Experimental results show that the proposed AIGAN achieves the state-of-the-art performances on commonly used metrics and satisfies the reconstruction needs for clinical standards.

Relapse after non-metastatic rhabdomyosarcoma: The impact of routine surveillance imaging on early detection and post-relapse survival

BACKGROUND

Patients with rhabdomyosarcoma (RMS) whose disease relapses have little chance of being cured, so front-line treatments are usually followed up with surveillance imaging in an effort to detect any recurrences as early as possible, and thereby improve post-relapse outcomes. The real benefit of such routine surveillance imaging in RMS remains to be demonstrated, however. This retrospective, single-center study examines how well surveillance imaging identifies recurrent tumors and its impact on post-relapse survival.

METHODS

The analysis concerned 79 patients <21 years old treated between 1985 and 2020 whose initially localized RMS relapsed. Clinical findings, treatment modalities, and survival were analyzed, comparing patients whose relapse was first suspected from symptoms they developed (clinical symptoms group) with those whose relapse was identified by radiological surveillance (routine imaging group).

RESULTS

Tumor relapses came to light because of clinical symptoms in 42 cases, and on routine imaging in 37. The time to relapse was much the same in the two groups. The median overall survival (OS) and 5-year OS rate were, respectively, 10 months and 12.6% in the clinical symptoms group, and 11 months and 27.5% in the routine imaging group (p-value .327). Among patients with favorable prognostic scores, survival was better for those in the routine imaging group (5-year OS 75.0% vs. 33.0%, p-value .047).

CONCLUSION

It remains doubtful whether surveillance imaging has any real impact on RMS relapse detection and patients' post-relapse survival. Further studies are needed to establish the most appropriate follow-up recommendations, taking the potentially negative effects of regular radiological exams into account.

Measurements of The Pediatric Cartilaginous Eustachian Tube: Implications for Balloon Dilation

OBJECTIVES

(1) Measure the cartilaginous Eustachian tube (ET) length using a computed tomography (CT) scan and (2) develop a prediction model to measure this length without the need of a CT scan.

STUDY DESIGN

CT measurements in children.

SETTING

Children's Hospital.

METHODS

CT scans were reformatted to project the cranial and caudal limits of the cartilaginous ET. The length was measured in 193 children who underwent a neck CT scan for nonotologic indications. Five physicians independently reviewed all or some of these measures. Four different models based on age, age ranges, weight, and height were created and compared to predict ET length.

RESULTS

The cartilaginous ET length was 25.3 ± 3.1 mm for the right and for the left ear. The mean ET length for the females was statistically significantly less than the length in males. The lower ET lengths in children as old as 5 years of age were less than the 2 cm adult criteria used for catheter insertion. All 4 models performed equally well in predicting ET length. Model number 4, which is based on height, was the easiest to calculate ET length.

CONCLUSION

The cartilaginous portion of the pediatric ET can be measured with good precision using reformatted CT images. We caution against using the "adult" criteria of 2 cm for catheter insertion in children, especially those younger than 5 years of age. We recommend using a model utilizing height measures to estimate ET length or direct measurements from a reformatted CT scan.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:396-402, 2023.

Assessing Radiation Dosage in Pediatric Head and Neck Computed Tomography Examinations During COVID-19 in a Tertiary Hospital in Saudi Arabia, Jeddah

This study aimed to assess the practice of imaging and optimization of the radiation dose in pediatric head and neck computed tomography (CT) examinations during the coronavirus disease of 2019 (COVID-19) period. This study is based on a retrospective analysis of pediatric head CT records, conducted in the Radiology Department of the King Abdulaziz University Hospital in Jeddah, Saudi Arabia. We examined the data of all pediatric patients between 0 and 14 years of age who underwent head CT scans between March and September in both 2019 (before the COVID-19 pandemic) and 2020 (during the COVID-19 pandemic). In total, we analyzed 1005 scans; 531 (52.8%) were performed before and 474 (47.2%) during COVID-19. The dose parameters were similar; however, the exposure time was significantly lower during COVID-19 (5432 ms vs. 5811 before; p < 0.001). In contrast, the mean total CTDI_vol and dose-length product (DLP) were slightly higher during COVID-19 than those before (23.34 mGy vs. 22.04 mGy (p-value=0.565) and 577.36 mGy*cm vs. 518.93 mGy*cm (p-value=0.193) respectively). These changes could be attributed to the desire to limit the contact between technicians and patients. The limitation of contact with the patient allows the technicians to be independent during the scan, possibly accounting for this slight decrease.

[Imaging after trauma in clinics and practice for children and adolescents : Part 1 of the results of a nationwide online survey of the Pediatric Traumatology Section of the German Trauma Society]

BACKGROUND

The indication for radiography should strictly follow the ALARA (as low as reasonably achievable) principle in pediatric and adolescent trauma patients. The effect of radiation on the growing sensitive tissue of these patients should not be disregarded.

QUESTION

The Pediatric Traumatology Section (SKT) of the German Trauma Society (DGU) wanted to clarify how the principle is followed in trauma care.

METHODS

An online survey was open for 10 weeks. Target groups were trauma surgeons, pediatric surgeons, general surgeons, and orthopedic surgeons.

RESULTS

From Nov. 15, 2019, to Feb. 29, 2020, 788 physicians participated: branch office 20.56%, MVZ 4.31%, hospital 75.13%; resident 16.62%, senior 38.07%, chief 22.59%. By specialist qualification, the distribution was: 38.34% surgery, 33.16% trauma surgery, 36.66% special trauma surgery, 70.34% orthopedics and trauma surgery, 18.78% pediatric surgery. Frequency of contact with fractures in the above age group was reported as 37% < 10/month, 27% < 20/M, 36% > 20/M. About 52% always request radiographs in 2 planes after acute trauma. X-ray of the opposite side for unclear findings was rejected by 70%. 23% use sonography regularly in fracture diagnosis. In polytrauma children and adolescents, whole-body CT is never used in 18%, rarely in 50%, and standard in 14%.

DISCUSSION

The analysis shows that there is no uniform radiological management of children and adolescents with fractures among the respondents.

CONCLUSION

Comparing the results of the survey with the consensus findings of the SKT recently published in this journal, persuasion is still needed to change the use of radiography in primary diagnosis.

Evaluation of image quality, organ doses, effective dose, and cancer risk from pediatric brain CT scans

PURPOSE

The present study was conducted to assess organ doses, effective dose, and image quality, and to estimate the risk of exposure-induced cancer death (REID) in pediatric brain computed tomography examinations.

METHODS

This investigation was performed on 179 pediatric patients (99 men and 80 women) under 12 years old who underwent non-contrast brain CT scans. Patients were classified into four age groups of ≤ 1, 2-5, 6-9, and 10-12 years old. Organ doses and effective doses were calculated using the ImpactDose program. Cancer risk models presented in the BEIR VII report were used to estimate REID values. Image quality assessment in this study was performed by measuring image quality parameters such as noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR).

RESULTS

The highest organ dose in all age groups belonged to the brain. The mean REID values were 12.34 per 100,000 males and 16.77 per 100,000 females. REID values decreased with the increasing age of patients in both genders and were higher for female children than male children. The mean SNR of gray matter, SNR of white matter, and CNR were 11.04, 10.5, and 2.31, respectively.

CONCLUSIONS

According to the results of this study, brain CT scans in children are associated with an increased potential risk of cancer. Therefore, minimizing unnecessary radiation exposure in pediatric patients and using alternative imaging modalities are of particular importance. Moreover, optimizing the radiation parameters while maintaining the diagnostic image quality in children should be considered.

Brain cancer after radiation exposure from CT examinations of children and young adults: results from the EPI-CT cohort study

BACKGROUND

The European EPI-CT study aims to quantify cancer risks from CT examinations of children and young adults. Here, we assess the risk of brain cancer.

METHODS

We pooled data from nine European countries for this cohort study. Eligible participants had at least one CT examination before age 22 years documented between 1977 and 2014, had no previous diagnosis of cancer or benign brain tumour, and were alive and cancer-free at least 5 years after the first CT. Participants were identified through the Radiology Information System in 276 hospitals. Participants were linked with national or regional registries of cancer and vital status, and eligible cases were patients with brain cancers according to WHO International Classification of Diseases for Oncology. Gliomas were analysed separately to all brain cancers. Organ doses were reconstructed using historical machine settings and a large sample of CT images. Excess relative risks (ERRs) of brain cancer per 100 mGy of cumulative brain dose were calculated with linear dose-response modelling. The outcome was the first reported diagnosis of brain cancer after an exclusion period of 5 years after the first electronically recorded CT examination.

FINDINGS

We identified 948 174 individuals, of whom 658 752 (69%) were eligible for our study. 368 721 (56%) of 658 752 participants were male and 290 031 (44%) were female. During a median follow-up of 5·6 years (IQR 2·4-10·1), 165 brain cancers occurred, including 121 (73%) gliomas. Mean cumulative brain dose, lagged by 5 years, was 47·4 mGy (SD 60·9) among all individuals and 76·0 mGy (100·1) among people with brain cancer. A significant linear dose-response relationship was observed for all brain cancers (ERR per 100 mGy 1·27 [95% CI 0·51-2·69]) and for gliomas separately (ERR per 100 mGy 1·11 [0·36-2·59]). Results were robust when the start of follow-up was delayed beyond 5 years and when participants with possibly previously unreported cancers were excluded.

INTERPRETATION

The observed significant dose-response relationship between CT-related radiation exposure and brain cancer in this large, multicentre study with individual dose evaluation emphasises careful justification of paediatric CTs and use of doses as low as reasonably possible.

FUNDING

EU FP7; Belgian Cancer Registry; La Ligue contre le Cancer, L'Institut National du Cancer, France; Ministry of Health, Labour and Welfare of Japan; German Federal Ministry of Education and Research; Worldwide Cancer Research; Dutch Cancer Society; Research Council of Norway; Consejo de Seguridad Nuclear, Generalitat de Catalunya, Spain; US National Cancer Institute; UK National Institute for Health Research; Public Health England.

Application of a Thoracic CT Decision Rule in the Evaluation of Injured Children: A Quality Improvement Initiative

BACKGROUND

Differences in injury patterns in children suggest that life-threatening chest injuries are rare. Radiation exposure from computed tomography increases cancer risk in children. Two large retrospective pediatric studies have demonstrated that thoracic computed tomography can be reserved for patients based on mechanism of injury and abnormal findings on chest radiography.

OBJECTIVE

Implement a decision rule to guide utilization of thoracic computed tomography in the evaluation of pediatric blunt trauma, limiting risk of unnecessary radiation exposure and clinically significant missed injuries.

METHODS

A protocol for thoracic computed tomography utilization in pediatric blunt trauma was implemented using a Plan-Do-Study-Act cycle at our Level I pediatric trauma center, reserving thoracic computed tomography for patients with (1) mediastinal widening on chest radiography or (2) vehicle-related mechanism and abnormal chest radiography. We modified our resuscitation order set to limit default imaging bundles. The medical record and trauma registry data were reviewed for all pediatric blunt trauma patients (younger than 18 years) over a 30-month study period before and after protocol implementation (May 2017 to July 2018 and February 2019 to April 2020), allowing for a 6-month implementation period (August 2018 to January 2019).

RESULTS

During the study period, 1,056 blunt trauma patients were evaluated with a median (range) Injury Severity Score of 5 (0-58). There were no significant demographic differences between patients before and after protocol implementation. Thoracic computed tomography utilization significantly decreased after implementation of the protocol (26.4% [129/488] to 12.7% [72/568; p < .05]), with no increase in clinically significant missed injuries. Protocol compliance was 88%.

CONCLUSIONS

Application of decision rules can safely limit ionizing radiation in injured children. Further limitations to thoracic computed tomography utilization may be safe and warrant continued study due to the rarity of significant injuries.

The use of MRI in the study of patients with idiopathic scoliosis: a systematic review of the literature

Objective. To analyze the frequency of hidden neuraxial pathology in idiopathic scoliosis (IS), to substantiate the need for MRI in IS and to identify promising areas for the use of MRI in the examination of patients with IS.Material and Methods. The literature review was carried out using the PubMed and Google Scholar databases. Of the 780 papers on the research topic, 65 were selected after removing duplicates and checking for inclusion/exclusion criteria. As a result, 49 original studies were included in the analysis. Level of evidence – II.Results. According to modern literature, the main direction of using MRI in idiopathic scoliosis is the search for predictors of latent pathology of the spinal cord and craniovertebral junction. The frequency of neuraxial pathology in idiopathic scoliosis is 8 % for adolescent IS and 16 % for early IS. The main predictors of neuraxial pathology are male sex, early age of deformity onset, left-sided thoracic curve and thoracic hyperkyphosis. MRI in IS may be a useful addition to radiological diagnostic methods to identify risk factors and to study degenerative changes in the spine.Conclusion. MRI of the spine should be performed in the early stages of IS to detect latent spinal cord tethering. In type I Chiari anomalies, there is a possibility that early neurosurgery can prevent the development of scoliosis. The main signs of latent neuraxial pathology in IS are early progression of spinal deformity, left-sided thoracic curve, male gender and thoracic kyphosis over 40° according to Cobb.MRI can be used as an effective non-invasive tool in research aimed at identifying risk factors for IS, including helping to track early degeneration of intervertebral discs.

Automatic Exposure Control Attains Radiation Dose Modulation Matched with the Head Size in Pediatric Brain CT

We investigated the relationship between the head size and radiation dose in pediatric brain computed tomography (CT) to evaluate the validity of automatic exposure control (AEC). Phantom experiments were performed to assess image noise with and without AEC, and indicated that AEC decreased differences in noise between slices of different section sizes. Retrospective analysis was conducted on 980 pediatric brain CT scans where the tube current was determined using AEC. The water equivalent diameter (WED) was employed as an index of the head size, and mean WED for each image set (WEDmean) and WED for each slice (WEDslice) were used for analysis. For the image-set-based analysis, volume CT dose index (CTDIvol) was compared to WEDmean. For the slice-based analysis, the tube current was compared to WEDslice using 20 of the 980 sets. Additionally, CTDIvol and WEDmean were compared between male and female patients matched for age, weight, or WEDmean. CTDIvol increased with increasing WEDmean, and an exponential curve was closely fitted to the relationship. Tube current changed similarly to the change in WEDslice for each image set, and an exponential curve was well-fitted to the plots of tube current against WEDslice when data from the 20 sets were pooled together. Although CTDIvol and WEDmean were slightly but significantly larger for male than female patients after matching for age or weight, a sex-dependent difference in CTDIvol was not found after matching for WEDmean. This study indicated successful dose modulation using AEC according to the head size for each patient and each slice location. The application of AEC to pediatric brain CT is recommended for radiation dose optimization.

The Evidence for Excess Risk of Cancer and Non-Cancer Disease at Low Doses and Dose Rates

The question of whether there are excess radiation-associated health risks at low dose is controversial. We present evidence of excess cancer risks in a number of (largely pediatrically or in utero exposed) groups exposed to low doses of radiation (<0.1 Gy). Moreover, the available data on biological mechanisms do not provide support for the idea of a low-dose threshold or hormesis for any of these endpoints. There are emerging data suggesting risks of cardiovascular disease and cataract at low doses, but this is less well established. This large body of evidence does not suggest and, indeed, is not statistically compatible with any very large threshold in dose (>10 mGy), or with possible beneficial effects from exposures. The presented data suggest that exposure to low-dose radiation causes excess cancer risks and quite possibly also excess risks of various non-cancer endpoints.

Cytogenetic Effects in Patients after Computed Tomography Examination

Millions of people around the world are exposed to low doses of ionizing radiation from diagnostic computed tomography (CT) scans. Currently available data on the potential cancer risk after CT scans are contradictory and therefore demand further investigations. The aim of the current study was to obtain estimations of genome damage after CT scans in 42 non-cancer patients and to conduct a comparison of the results with 22 control subjects. The frequency of dicentric ring chromosomes and chromosome breaks was significantly increased in irradiated patients compared to the controls. The distribution of dicentrics among the cells demonstrated non-Poisson distribution that reflected non-uniform and partial-body radiation exposure. A fraction of patients followed Poisson distribution, which is typical for uniform whole-body exposures. Some patients demonstrated a level of dicentrics similar to the control subjects. The individual variations in the frequency and dicentric distribution suggested complex mechanisms of chromosome aberration induction and elimination that could be associated with individual radiosensitivity, as well as previous diagnostics that used ionizing radiation or the redistribution of small fractions of irradiated lymphocytes within the circulatory pull. In conclusion, CT scans may cause genome damage and possible increases in cancer risk. The introduction of a specific follow-up of such patients, especially in the case of repeated CT scans, is suggested.

MRI-guided microwave ablation and albumin-bound paclitaxel for lung tumors: Initial experience

Magnetic resonance-guided microwave ablation (MRI-guided MWA) is a new, minimally invasive ablation method for cancer. This study sought to analyze the clinical value of MRI-guided MWA in non-small cell lung cancer (NSCLC). We compared the precision, efficiency, and clinical efficacy of treatment in patients who underwent MRI-guided MWA or computed tomography (CT)-guided microwave ablation (CT-guided MWA). Propensity score matching was used on the prospective cohort (MRI-MWA group, n = 45) and the retrospective observational cohort (CT-MWA group, n = 305). To evaluate the advantages and efficacy of MRI-guided MWA, data including the accuracy of needle placement, scan duration, ablation time, total operation time, length of hospital stay, progression-free survival (PFS), and overall survival (OS) were collected and compared between the two groups. The mean number of machine scans required to adjust the needle position was 7.62 ± 1.69 (range 4–12) for the MRI-MWA group and 9.64 ± 2.14 (range 5–16) for the CT-MWA group (p < 0.001). The mean time for antenna placement was comparable between the MRI and CT groups (54.41 ± 12.32 min and 53.03 ± 11.29 min, p = 0.607). The microwave ablation time of the two groups was significantly different (7.62 ± 2.65 min and 9.41 ± 2.86 min, p = 0.017), while the overall procedure time was comparable (91.28 ± 16.69 min vs. 93.41 ± 16.03 min, p = 0.568). The overall complication rate in the MRI-MWA group was significantly lower than in the CT-MWA group (12% vs. 51%, p = 0.185). The median time to progression was longer in the MRI-MWA group than in the CT-MWA group (11 months [95% CI 10.24–11.75] vs. 9 months [95% CI 8.00–9.99], p = 0.0003; hazard ratio 0.3690 [95% CI 0.2159–0.6306]). OS was comparable in both groups (MRI group 26.0 months [95% CI 25.022–26.978] vs. CT group 23.0 months [95% CI 18.646–27.354], p = 0.18). This study provides hitherto-undocumented evidence of the clinical effects of MRI-guided MWA on patients with NSCLC and determines the relative safety and efficiency of MRI- and CT-guided MWA.

Barriers and facilitators of CT scan reduction in the workup of pediatric appendicitis: A pediatric surgical quality collaborative qualitative study

INTRODUCTION

Despite ongoing efforts to decrease ionizing radiation exposure from computed tomography (CT) use in pediatric appendicitis, high CT utilization rates are still observed across many hospitals. This study aims to identify factors influencing CT use and facilitators and barriers to quality improvement efforts.

METHODS

The Pediatric Surgery Quality Collaborative is a voluntary consortium of 42 children's hospitals participating in the National Surgical Quality Improvement Project - Pediatric. Hospitals were compared based on CT utilization from January 1, 2019, to December 31, 2019. Semi-structured interviews were conducted with surgeons, radiologists, emergency medicine physicians, and clinical data abstractors from 7 hospitals with low CT use rates (high performers) and 6 hospitals with high CT use rates (low performers). A mixed deductive and inductive coding approach for analysis of the interview transcripts was used to develop a codebook based on the Theoretical Domains Framework and subsequently identify prominent barriers and facilitators to CT reduction.

RESULTS

Thematic saturation was achieved after 13 interviews. We identified four factors that distinguish high-performing from low-performing hospitals: (1) consistent availability of resources such as ultrasound technicians, pediatric radiologists, and magnetic resonance imaging (MRI); (2) presence of and adherence to protocols guiding imaging modality decision making and imaging execution; (3) culture of inter-departmental collaboration; and (4) presence of a radiation reduction champion.

CONCLUSIONS

Significant barriers to reducing the use of CT in pediatric appendicitis exist. Our findings highlight that future quality improvement efforts should target resource availability, protocol adherence, collaborative culture, and radiation reduction champions.

LEVELS OF EVIDENCE

Level III.

Cancer Effects of Low to Moderate Doses of Ionizing Radiation in Young People with Cancer-Predisposing Conditions: A Systematic Review

Moderate to high doses of ionizing radiation (IR) are known to increase the risk of cancer, particularly following childhood exposure. Concerns remain regarding risks from lower doses and the role of cancer-predisposing factors (CPF; genetic disorders, immunodeficiency, mutations/variants in DNA damage detection or repair genes) on radiation-induced cancer (RIC) risk. We conducted a systematic review of evidence that CPFs modify RIC risk in young people. Searches were performed in PubMed, Scopus, Web of Science, and EMBASE for epidemiologic studies of cancer risk in humans (&lt;25 years) with a CPF, exposed to low-moderate IR. Risk of bias was considered. Fifteen articles focusing on leukemia, lymphoma, breast, brain, and thyroid cancers were included. We found inadequate evidence that CPFs modify the risk of radiation-induced leukemia, lymphoma, brain/central nervous system, and thyroid cancers and limited evidence that BRCA mutations modify radiation-induced breast cancer risk. Heterogeneity was observed across studies regarding exposure measures, and the numbers of subjects with CPFs other than BRCA mutations were very small. Further studies with more appropriate study designs are needed to elucidate the impact of CPFs on RIC. They should focus either on populations of carriers of specific gene mutations or on common susceptible variants using polygenic risk scores.

Differences in the management of thyroid nodules in children and adolescents as compared to adults

PURPOSE OF REVIEW

To describe recent advances in the diagnosis and management of thyroid nodules in both children and adults, highlighting differences between the two groups.

RECENT FINDINGS

Thyroid nodules are less common in children than adults but the risk of malignancy is higher. Screening recommendations for patients with certain genetic syndromes or specific risk factors for thyroid nodules and cancer continue to evolve ultrasound is the most appropriate imaging modality for evaluating thyroid nodules in all patients, but radiographic risk stratification systems validated in adults have not been extensively studied in children. Criteria for proceeding to fine needle aspiration (FNA) biopsy differ some between children and adults, with nodule size being less of a consideration in young patients. Molecular testing continues to improve the diagnostic capabilities of FNA for all age groups, but options for pediatric thyroid nodules are currently limited. In children, only oncogene panels are validated and their exact utility, along with miRNA classifiers, is an evolving area of study. For adults, data support selection of a specific molecular test based on ultrasound characteristics and pretest probability of malignancy. Multiple series have shown that fusion mutations are more common in pediatric thyroid nodules, while point mutations are seen more often in adult thyroid nodules. Molecular data help guide management recommendations regarding the need for surgery when FNA is indeterminate, but clinical use is still being refined. Radiofrequency ablation is a nonoperative approach that has gained significant traction for the treatment of symptomatic benign nodules in adults, but data are currently extremely limited in children.

SUMMARY

There are difference in the diagnosis and treatment of thyroid nodules in adults and children, the nuances of which are important for clinical management.

Sample Size and Estimation of Standard Radiation Doses for Pediatric Brain CT

Estimation of the standard radiation dose at each imaging facility is required for radiation dose management, including establishment and utilization of the diagnostic reference levels. We investigated methods to estimate the standard dose for pediatric brain computed tomography (CT) using a small number of data. From 980 pediatric brain CT examinations, 25, 50, and 100 examinations were randomly extracted to create small, medium, and large datasets, respectively. The standard dose was estimated by applying grouping and curve-fitting methods for 20 datasets of each sample size. For the grouping method, data were divided into groups according to age or body weight, and the standard dose was defined as a median value in each group. For the curve-fitting methods, logarithmic, power, and bilinear functions were fitted to plots of radiation dose against age or weight, and the standard dose was calculated at the designated age or weight using the derived equation. When the sample size was smaller, the random variations of the estimated standard dose were larger. Better estimation of the standard dose was achieved with the curve-fitting methods than with the grouping method. Power fitting appeared to be more effective than logarithmic and bilinear fittings for suppressing random variation. Determination of the standard dose for pediatric brain CT by the curve-fitting method is recommended to improve radiation dose optimization at facilities performing the imaging procedure infrequently.

Ionizing radiation exposure during adulthood and risk of developing central nervous system tumors: systematic review and meta-analysis

Many studies on ionizing radiation (IR) exposure during childhood have shown deleterious effects on the central nervous system (CNS), however results regarding adult exposure are inconsistent, and no systematic reviews have been performed. The objectives are to synthesize the findings and draw evidence-based conclusions from epidemiological studies on the risk of benign and malignant brain and CNS tumors in humans exposed to low-to-moderate doses (< 0.5 Gy) of IR during adulthood/young adulthood. A systematic literature search of four electronic databases, supplemented by a hand search, was performed to retrieve relevant epidemiological studies published from 2000 to 2022. Pooled excess relative risk (ERR_pooled) was estimated using a random effect model. Eighteen publications were included in the systematic review and twelve out of them were included in a meta-analysis. The following IR sources were considered: atomic bombs, occupational, and environmental exposures. No significant dose-risk association was found for brain/CNS tumors (ERR_pooled at 100 mGy = − 0.01; 95% CI: − 0.05, 0.04). Our systematic review and meta-analysis did not show any association between exposure to low-to-moderate doses of IR and risk of CNS tumors. Further studies with histological information and precise dose assessment are needed.

Relapsing pediatric non-rhabdomyosarcoma soft tissue sarcomas: The impact of routine imaging surveillance on early detection and post-relapse survival

PURPOSE

The chances of patients with relapsing pediatric non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) being cured are limited. This retrospective single-institutional study examines the potential role of routine surveillance imaging for detecting recurrent tumor, and its impact on post-relapse survival.

METHODS

The analysis concerned 86 patients < 21 years old with relapsing NRSTS treated from 1985 to 2020. Clinical findings, treatment modalities and survival were analyzed, comparing patients whose relapse was first suspected from symptoms (symptomatic group) with those whose relapse was detected by radiological surveillance (imaging group).

RESULTS

Tumor relapses were identified from clinical symptoms in 49 cases and on routine imaging in 37. Time to relapse was similar in the two groups. Routine imaging detected 6/32 local relapses and 31/48 distant relapses (and 79% of the cases of lung metastases). Overall survival (OS) at 5 years was 34.3% for the symptomatic group, and 24.0% for the imaging group (p-value 0.270). In patients with lung metastases at relapse, the 5-year OS was statistically better for the imaging group, that is, 25.8% versus 0% for the symptomatic group (p-value 0.044).

CONCLUSION

This is the first study to explore the role of surveillance imaging in pediatric NRSTS. Judging from our findings, the value of routine scanning of primary sites seems limited, while radiological surveillance may help to detect lung metastases, improving survival for this patient category. The potentially negative effects of periodic radiological exams should be considered in deciding the optimal follow-up for patients off therapy.

CBTRUS Statistical Report: Pediatric Brain Tumor Foundation Childhood and Adolescent Primary Brain and Other Central Nervous System Tumors Diagnosed in the United States in 2014-2018

The CBTRUS Statistical Report: Pediatric Brain Tumor Foundation Childhood and Adolescent Primary Brain and Other Central Nervous System Tumors Diagnosed in the United States in 2014-2018 comprehensively describes the current population-based incidence of primary malignant and non-malignant brain and other CNS tumors in children and adolescents ages 0-19 years, collected and reported by central cancer registries covering approximately 100% of the United States population. Overall, brain and other CNS tumors are the most common solid tumor, the most common cancer, and the most common cause of cancer death in children and adolescents ages 0-19 years. This report aims to serve as a useful resource for researchers, clinicians, patients, and families.

BIOLOGICAL EFFECTS OF LOW-DOSE RADIATION FROM CT IMAGING

The dramatic rise in diagnostic procedures, radioisotope-based scans and intervention procedures has created a very valid concern regarding the long-term biological consequences from exposure to low doses of ionizing radiation. Despite its unambiguous medical benefits, additional knowledge on the health outcome of its use is essential. This review summarizes the available information regarding the biological consequences of low-dose radiation (LDR) exposure in humans (e.g. cytogenetic changes, cancer risk and radiation-induced cataracts. However, LDR studies remain relatively new and thus an encompassing view of its biological effects and relevant mechanisms in the human body is still needed.

Reliability and accuracy of dental MRI for measuring root canal length of incisors and canines: a clinical pilot study

To evaluate whether high-resolution, non-contrast-enhanced dental MRI (dMRI) can reliably and accurately measure the canal length of incisors and canines compared with cone-beam computed tomography (CBCT). Three-Tesla dMRI was performed in 31 participants (mean age: 50.1 ± 14.2 years) with CBCT data. In total, 67 teeth were included (28 from the upper jaw and 39 from the lower jaw; 25 central incisors, 22 lateral incisors, and 20 canines). CBCT and dMRI datasets were reconstructed to visualize the root canal pathway in a single slice in the vestibulo-oral (V-O) and mesio-distal (M-D) direction. Root canal length was measured twice by two radiologists using dMRI and CBCT. Data were statistically analyzed by calculating intraclass correlation coefficients (ICCs) and performing Bland–Altman analysis. The reliability of dMRI measurements was excellent and comparable to that of CBCT measurements (intra-rater I/intra-rater II/inter-rater was 0.990/0.965/0.951 for dMRI vs. 0.990/0.994/0.992 for CBCT in the M-D direction and 0.991/0.956/0.967 for dMRI vs. 0.998/0.994/0.996 for CBCT in the V-O direction). According to Bland–Altman analysis, the mean (95% confidence interval) underestimation of root canal lengths was 0.67 mm (− 1.22 to 2.57) for dMRI and 0.87 mm (− 0.29 to 2.04) for CBCT in the M-D direction/V-O direction. In 92.5% of cases, dMRI measurements of canal length had an accuracy within 0–2 mm. Visualization and measurement of canal length in vivo using dMRI is feasible. The reliability of dMRI measurements was high and comparable to that of CBCT measurements. However, the spatial and temporal resolution of dMRI is lower than that of CBCT, which means dMRI measurements are less accurate than CBCT measurements. This means dMRI is currently unsuitable for measuring canal length in clinical practice.

Determining the diagnostic value of three clinical criteria Wells', YEARS and modified Geneva in pregnant women with suspected pulmonary thromboembolism

BACKGROUND

Diagnosis of pulmonary thromboembolism (PTE) during pregnancy is a challenging medical issue due to complications of X-ray-based imaging studies such as Ct-angiography for neonates and pregnant women. Here we aimed to assess the predictive values of three clinical criteria for diagnosing PTE during pregnancy.

METHODS

This is a retrospective cohort study performed in 2018-2020 on 166 pregnant women suspected of PTE. We reviewed the documents of all patients referred to our medical center with suspected symptoms of PTE. The demographic characteristics of the patients, signs and clinical findings upon the arrival of patients as well as their laboratory tests including D-dimer with a history of abortion or delivery and leg symptoms were entered into the data collection form. Then, according to the information extracted from the patient's files, each patient was evaluated by all clinical PTE criteria, including Wells, YEARS and modified Geneva. For each patient according to clinical criteria and all three algorithms, clinical suspicion for PTE and treatment or non-treatment was determined were compared to the final MDCT result of patients.

RESULTS

The Well's criteria had 100% sensitivity, 6.47% specificity, a positive predictive value of 7.8% and a negative predictive value of 100%. In patients with Well's score of more than four, the sensitivity and specificity of PTE diagnosis were 100% and 6% respectively. The modified Geneva criteria had 100% sensitivity, 8.89% specificity, a positive predictive value of 8.21% and a negative predictive value of 100%. The modified Geneva criteria had 100% sensitivity, 7.74% specificity, positive predictive value of 8.44% and a negative predictive value of 100%.

CONCLUSION

Wells, YEARS and modified Geneva criteria could significantly rule out PTE in pregnancy with 100% sensitivity.

Childhood cancer risks estimates following CT scans: an update of the French CT cohort study

OBJECTIVES

Increased risks of central nervous system (CNS) tumors and leukemia associated with computed tomography (CT) exposure during childhood have been reported in recent epidemiological studies. However, no evidence of increased risks was suggested in a previous analysis of the French CT cohort. This study benefits from an updated cohort with a longer follow-up and a larger sample size of patients.

METHODS

The patients were followed from the date of their first CT (between 2000 and 2011) until their date of cohort exit defined as the earliest among the following: 31 December 2016, date of death, date of first cancer diagnosis or date of their 18^th birthday. Cancer incidence, vital status, cancer predisposing factors (PFs), and additional CT scans were collected via external national databases. Hazard ratios (HRs) associated to cumulative organ doses and sex were estimated from Cox models.

RESULTS

At the end of follow-up, mean cumulative doses were 27.7 and 10.3 mGy for the brain and the red bone marrow (RBM), respectively. In patients without PFs, an HR per 10 mGy of 1.05 (95% CI: 1.01-1.09) for CNS tumors, 1.17 (95% CI: 1.09-1.26) for leukemia, and 0.96 (95% CI: 0.63-1.45) for lymphoma was estimated. These estimates were not modified by the inclusion of CT scans performed outside the participating hospitals or after the inclusion period.

CONCLUSIONS

This study shows statistically significant dose-response relationships for CNS tumors and leukemia for patients without PFs.

KEY POINTS

• Computed tomography is the most important contributor to the collective dose for diagnostic imaging to the French population. • Concerns have been raised about possible cancer risks, particularly after exposure to CT in childhood, due to the greater radiation sensitivity of children and to their longer life expectancy. • Analysis of the updated French CT cohort shows statistically significant dose-response relationships for CNS tumors and leukemia.

Cancer risks among studies of medical diagnostic radiation exposure in early life without quantitative estimates of dose

BACKGROUND

There is accumulating evidence of excess risk of cancer in various populations exposed at acute doses below several tens of mSv or doses received over a protracted period. There is also evidence that relative risks are generally higher after radiation exposures in utero or in childhood.

METHODS AND FINDINGS

We reviewed and summarised evidence from 89 studies of cancer following medical diagnostic exposure in utero or in childhood, in which no direct estimates of radiation dose are available. In all of the populations studied exposure was to sparsely ionizing radiation (X-rays). Several of the early studies of in utero exposure exhibit modest but statistically significant excess risks of several types of childhood cancer. There is a highly significant (p < 0.0005) negative trend of odds ratio with calendar period of study, so that more recent studies tend to exhibit reduced excess risk. There is no significant inter-study heterogeneity (p > 0.3). In relation to postnatal exposure there are significant excess risks of leukaemia, brain and solid cancers, with indications of variations in risk by cancer type (p = 0.07) and type of exposure (p = 0.02), with fluoroscopy and computed tomography scans associated with the highest excess risk. However, there is highly significant inter-study heterogeneity (p < 0.01) for all cancer endpoints and all but one type of exposure, although no significant risk trend with calendar period of study.

CONCLUSIONS

Overall, this large body of data relating to medical diagnostic radiation exposure in utero provides support for an associated excess risk of childhood cancer. However, the pronounced heterogeneity in studies of postnatal diagnostic exposure, the implied uncertainty as to the meaning of summary measures, and the distinct possibilities of bias, substantially reduce the strength of the evidence from the associations we observe between radiation imaging in childhood and the subsequent risk of cancer being causally related to radiation exposure.

MRI evaluation of pediatric tibial eminence fractures: comparison between conventional and "CT-like" ultrashort echo time (UTE) images

OBJECTIVE

UTE MRI offers a radiation-free alternative to CT for bone depiction, but data on children is lacking. The purpose of this study was to determine whether UTE images improve detection and characterization of pediatric tibial eminence fractures.

METHODS

Fifteen MRIs with UTE from 12 children (10 boys, 2 girls; mean age: 12.6 ± 3.3 years) with tibial eminence fractures (2018-2020) and 15 age-matched MRIs without fractures were included. After randomization, 5 readers reviewed images without and with UTE, at least 1 month apart, and recorded the presence of fracture and preferred images. If fracture is present, radiologists also recorded fragment size, number, and displacement; surgeons assigned Meyers-McKeever grade and management. Disagreements on management were resolved through consensus review. Kappa and intra-class correlation (ICC), sensitivity, and specificity were used to compare agreement between readers and fracture detection between images without and with UTE.

RESULTS

For fracture detection, inter-reader agreement was almost perfect (κ-range: 0.91-0.93); sensitivity and specificity were equivalent between images without and with UTE (range: 95-100%). For fracture characterization, UTE improved agreement on size (ICC = 0.88 to 0.93), number (ICC = 0.52 to 0.94), displacement (ICC = 0.74 to 0.86), and grade (ICC = 0.92 to 0.93) but reduced agreement on management (κ = 0.68 to 0.61), leading to a change in consensus management in 20% (3/15). Radiologists were more likely to prefer UTE for fracture and conventional images for non-fracture cases (77% and 77%, respectively, p < 0.001).

CONCLUSION

While UTE did not improve diagnosis, it improved agreement on characterization of pediatric tibial eminence fractures, ultimately changing the preferred treatment in 20%.

Endodontic working length measurements of premolars and molars in high-resolution dental MRI: a clinical pilot study for assessment of reliability and accuracy

OBJECTIVES

To prospectively assess the reliability and accuracy of high-resolution, dental MRI (dMRI) for endodontic working length (WL) measurements of premolars and molars under clinical conditions.

MATERIALS AND METHODS

Three-Tesla dMRI was performed in 9 subjects who also had undergone cone-beam computed tomography (CBCT) (mean age: 47 ± 13.5 years). A total of 34 root canals from 12 molars (4/8, upper/lower jaw; 22 root canals) and 11 premolars (2/9 upper/lower jaw; 12 root canals) were included. CBCT and dMRI datasets were reconstructed to visualize the root canal in one single slice. Subsequently, two radiologists measured the root canal lengths in both modalities twice in blinded fashion. Reliability and accuracy for both modalities were assessed using intraclass correlation coefficients (ICCs) and Bland-Altman analysis, respectively.

RESULTS

Reliability (intra-rater I/II; inter-rater) of dental MRI measurements was excellent and comparable to CBCT for premolars (0.993/0.900; 0.958 vs. 0.993/0.956; 0.951) and for molars (0.978/0.995; 0.986 vs. 0.992/0.996; 0.989). Bland-Altman analysis revealed a mean underestimation/bias (95% confidence interval) of dMRI measurements of 0.8 (- 1.44/3.05) mm for premolars and 0.4 (- 1.55/2.39) mm for molars. In up to 59% of the cases, the accuracy of dMRI for WL measurements was within the underestimation margin of 0 to 2 mm short of the apical foramen AF.

CONCLUSIONS

In vivo demonstration and measurement of WL are feasible using dMRI. The reliability of measurements is high and equivalent to CBCT. Nonetheless, due to lower spatial resolution and longer acquisition time, the accuracy of dMRI is inferior to CBCT, impeding its current use for clinical treatment planning.

CLINICAL RELEVANCE

dMRI is a promising radiation-free imaging technique. Its reliability for endodontic working length measurements is high, but its accuracy is not satisfactory enough yet.

Incidence trends of childhood central nervous system tumors in Finland 1990-2017

Introduction

Central nervous system (CNS) tumors are a leading cause of cancer-related morbidity and mortality in children. Our aim is to characterize incidence trends of pediatric CNS tumors in Finland over the last three decades.

Methods

Data on all benign and malignant incident CNS tumors diagnosed in children aged 0–14 years in 1990–2017 were extracted from the Finnish Cancer Registry and classified according to the 2016 WHO classification of CNS tumors. We analyzed age-standardized incidence rates (ASR) for pediatric CNS tumors overall and by sex, age, tumor histology, grade, and location using Poisson regression. We used joinpoint regression to evaluate changes in trends.

Results

Overall, 1117 pediatric CNS tumor cases were registered in Finland with a 1.2:1 male to female ratio. The average annual ASR was 4.3 per 100,000 person-years (95% CI 4.26, 4.34). The most common tumor type was pilocytic astrocytoma (30% of tumors), followed by medulloblastoma (10%) with incidence rates of 1.30 and 0.45 per 100,000 person-years, respectively. The overall incidence of pediatric CNS tumors increased by an annual percentage change (APC) of 0.8% (95% CI 0.2, 1.4). We observed no major changes in incidence trends of tumor histology groups or tumor location groups. The ASR of benign tumors increased by an APC of 1.0 (95% CI 0.1, 2.0).

Conclusions

Utilizing the high-quality and completeness of data in the Finnish Cancer registry, we found that the incidence of pediatric CNS tumors in Finland has increased slightly from 1990 until 2017. Although variations in diagnostic and registration practices over time might have affected the rates, the trend may also reflect a true increase in incidence.

A case of an air gun bullet paranasal sinuses injury in an 11-year-old male

Non-powder firearms, such as BB guns, are considered safer than traditional firearms and are often marketed toward younger demographics as children’s toys. Recent advances in compressed-gas technology have drastically increased the firing power of these types of firearms, which has caused them to be more dangerous and capable of causing severe injury. We report the case of an 11-year-old male admitted for nasal injury caused by a BB gun pellet. The projectile had an unpredictable course: it pierced the skin of his left nasal sidewall, traversed through the soft tissues of the nose to the right nasal cavity violating the posterior septum, and lodged in the right posterior ethmoids adjacent to the posterior attachment of the middle turbinate. The metallic foreign object was successfully retrieved from the right nasal cavity via an endoscopic approach after minimal endoscopic dissection, guided by the preoperative radiologic imaging.

The Potential of S100 Calcium-Binding Protein B and Glial Fibrillary Acid Protein in Predicting the Intracranial Lesions in Mild Traumatic Brain Injury: A Systematic Review of Literature

ABSTRACT AIM: To summarize the current evidence of S100B and GFAP in predicting intracranial lesions after mTBI. MATERIAL AND METHODS: We searched publications on biomarkers in mTBI from Web of Science, PubMed, and Scopus between January 1990 and July 2021. We included RCTs, cohort, case control, and cross-sectional studies that involved patients with acute closed mTBI in all age group in which head CT scan and blood-based biomarkers (GFAP and S100B) examination were conducted under 24 hours. This study was registered in Open Science Framework. RESULTS: The initial search identified 4.937 article, in which 127 were included for full-text assessment. A total of 16 articles were finally included. No RCT was found in literature searching. Thirteen studies were studying S100B and three studies were studying GFAP. Nine out of 13 S100B studies shows a promising result with ≥ 95% sensitivity for detecting intracranial lesions.  Majorities (11 /13) studies of  S100B confirmed that S100B reduced the unnecessary usage of CT scan. GFAP concentration significantly increased in CT+ patient than CT- patient. No specific GFAP cut off value between the studies was found. CONCLUSION: The result showed that S100B and GFAP had potential to predict the occurrence of intracranial lesions. Variance between methodologies and cut off value hindered the quality of evidence, especially in GFAP. KEYWORDS: mild traumatic brain injury, S100B, GFAP.

High-performance reconstruction of CT medical images by using out-of-core methods in GPU

BACKGROUND AND OBJECTIVE

Since Computed Tomography (CT) is one of the most widely used medical imaging tests, it is essential to work on methods that reduce the radiation the patient is exposed to. Although there are several possible approaches to achieve this, we focus on reducing the exposure time through sparse sampling. With this approach, efficient algebraic methods are needed to be able to generate the images in real time, and since their computational cost is high, using high-performance computing is essential.

METHODS

In this paper we present a GPU (Graphics Processing Unit) software for solving the CT image reconstruction problem using the QR factorization performed with out-of-core (OOC) techniques. This implementation is optimized to reduce the data transfer times between disk, CPU, and GPU, as well as to overlap input/output operations and computations.

RESULTS

The experimental study shows that a block cache stored on main page-locked memory is more efficient than using a cache on GPU memory or mirroring it in both GPU and CPU memory. Compared to a CPU version, this implementation is up to 6.5 times faster, providing an improved image quality when compared to other reconstruction methods.

CONCLUSIONS

The software developed is an optimized version of the QR factorization for GPU that allows the algebraic reconstruction of CT images with high quality and resolution, with a performance that can be compared with state-of-the-art methods used in clinical practice. This approach allows reducing the exposure time of the patient and thus the radiation dose.

[Skull and skull base injuries in children and adolescents : Results of a monocentric analysis]

BACKGROUND

The present study comprises a retrospective analysis of skull, skull base, and midface fractures in children, to provide clinical orientation for their management. To date, only few data are available on these injuries in this patient group.

METHODS

Data from inpatient cases diagnosed with a midface, skull, or skull base fracture in the Children's Hospital Auf der Bult from 2015 to 2020 were evaluated. Age, gender, fracture mechanism, diagnosis, treatment, and possible complications were analyzed. Data of 224 children were grouped into 107 cases with nose fractures, 104 cases with skull fractures, 9 patients with temporal bone fractures, 4 patients with rhinobasal fractures, and 2 cases with fractures of the orbital floor.

RESULTS

Among patients with nose fractures, the average age was 10.9 years (64% males), among patients with skull fractures 1.0 year (64% males), and in children with skull base fractures 6.0 years (85% males). Falls were the most frequent genesis (63%), followed by car accidents, collisions (25%), and violence (10%). Patients with skull fractures underwent sonography in 94% of cases; in 87% the fracture was verified. Patients with nose fractures underwent x‑ray in 92% of cases, or sonography only in 8%; 95% of patients with nose fractures underwent operative repositioning. Typical fracture signs (i.e., hemotympanum, ophthalmic symptoms) or signs of central nervous system involvement (i.e., nausea, amnesia) occurred in 12 of 13 children with skull base fractures, and CT was performed in all these cases (none of whom developed a cerebrospinal fluid leak).

CONCLUSION

The imaging modality should be selected based on the clinically suspected diagnosis and the course. Most fractures can be sufficiently treated without any permanent sequelae, except for nose fractures, which frequently require operative repositioning.

Radiation Dose Management in Pediatric Brain CT According to Age and Weight as Continuous Variables

The diagnostic reference levels (DRLs) for pediatric brain computed tomography (CT) are provided for groups divided according to age. We investigated the relationships of radiation dose indices (volume CT dose index and dose length product) with age and weight, as continuous variables, in pediatric brain CT. In a retrospective analysis, 980 pediatric brain CT examinations were analyzed. Curve fitting was performed for plots of the CT dose indices versus age and weight, and equations to estimate age- and weight-dependent standard dose indices were derived. Standard dose indices were estimated using the equations, and the errors were calculated. The results showed a biphasic increase in dose indices with increasing age and weight, characterized by a rapid initial and subsequent slow increase. Logarithmic, power, and bilinear functions were well fitted to the plots, allowing estimation of standard dose indices at an arbitrary age or weight. Error analysis suggested that weight was mildly better than age and that the best results were obtained with the bilinear function. Curve fitting of the relationship between CT dose indices and age or weight facilitates the determination of standard dose indices in pediatric brain CT at each facility and is expected to aid the establishment and application of the DRLs.

A deep learning algorithm to identify cervical ossification of posterior longitudinal ligaments on radiography

The cervical ossification of the posterior longitudinal ligament (cOPLL) is sometimes misdiagnosed or overlooked on radiography. Thus, this study aimed to validate the diagnostic yield of our deep learning algorithm which diagnose the presence/absence of cOPLL on cervical radiography and highlighted areas of ossification in positive cases and compare its diagnostic accuracy with that of experienced spine physicians. Firstly, the radiographic data of 486 patients (243 patients with cOPLL and 243 age and sex matched controls) who received cervical radiography and a computer tomography were used to create the deep learning algorithm. The diagnostic accuracy of our algorithm was 0.88 (area under curve, 0.94). Secondly, the numbers of correct diagnoses were compared between the algorithm and consensus of four spine physicians using 50 independent samples. The algorithm had significantly more correct diagnoses than spine physicians (47/50 versus 39/50, respectively; p = 0.041). In conclusion, the accuracy of our deep learning algorithm for cOPLL diagnosis was significantly higher than that of experienced spine physicians. We believe our algorithm, which uses different diagnostic criteria than humans, can significantly improve the diagnostic accuracy of cOPLL when radiography is used.

Quantifying cancer risk from exposures to medical imaging in the Risk of Pediatric and Adolescent Cancer Associated with Medical Imaging (RIC) Study: research methods and cohort profile

PURPOSE

The Risk of Pediatric and Adolescent Cancer Associated with Medical Imaging (RIC) Study is quantifying the association between cumulative radiation exposure from fetal and/or childhood medical imaging and subsequent cancer risk. This manuscript describes the study cohorts and research methods.

METHODS

The RIC Study is a longitudinal study of children in two retrospective cohorts from 6 U.S. healthcare systems and from Ontario, Canada over the period 1995-2017. The fetal-exposure cohort includes children whose mothers were enrolled in the healthcare system during their entire pregnancy and followed to age 20. The childhood-exposure cohort includes children born into the system and followed while continuously enrolled. Imaging utilization was determined using administrative data. Computed tomography (CT) parameters were collected to estimate individualized patient organ dosimetry. Organ dose libraries for average exposures were constructed for radiography, fluoroscopy, and angiography, while diagnostic radiopharmaceutical biokinetic models were applied to estimate organ doses received in nuclear medicine procedures. Cancers were ascertained from local and state/provincial cancer registry linkages.

RESULTS

The fetal-exposure cohort includes 3,474,000 children among whom 6,606 cancers (2394 leukemias) were diagnosed over 37,659,582 person-years; 0.5% had in utero exposure to CT, 4.0% radiography, 0.5% fluoroscopy, 0.04% angiography, 0.2% nuclear medicine. The childhood-exposure cohort includes 3,724,632 children in whom 6,358 cancers (2,372 leukemias) were diagnosed over 36,190,027 person-years; 5.9% were exposed to CT, 61.1% radiography, 6.0% fluoroscopy, 0.4% angiography, 1.5% nuclear medicine.

CONCLUSION

The RIC Study is poised to be the largest study addressing risk of childhood and adolescent cancer associated with ionizing radiation from medical imaging, estimated with individualized patient organ dosimetry.

One-stop local and whole-body staging of children with cancer

Accurate staging and re-staging of cancer in children is crucial for patient management. Currently, children with a newly diagnosed cancer must undergo a series of imaging tests, which are stressful, time-consuming, partially redundant, expensive, and can require repetitive anesthesia. New approaches for pediatric cancer staging can evaluate the primary tumor and metastases in a single session. However, traditional one-stop imaging tests, such as CT and positron emission tomography (PET)/CT, are associated with considerable radiation exposure. This is particularly concerning for children because they are more sensitive to ionizing radiation than adults and they live long enough to experience secondary cancers later in life. In this review article we discuss child-tailored imaging tests for tumor detection and therapy response assessment - tests that can be obtained with substantially reduced radiation exposure compared to traditional CT and PET/CT scans. This includes diffusion-weighted imaging (DWI)/MRI and integrated [F-18]2-fluoro-2-deoxyglucose (18F-FDG) PET/MRI scans. While several investigators have compared the value of DWI/MRI and 18F-FDG PET/MRI for staging pediatric cancer, the value of these novel imaging technologies for cancer therapy monitoring has received surprisingly little attention. In this article, we share our experiences and review existing literature on this subject.

Organ dose conversion coefficients in CT scans for Korean adult males and females

Dose monitoring in CT patients requires accurate dose estimation but most of the CT dose calculation tools are based on Caucasian computational phantoms. We established a library of organ dose conversion coefficients for Korean adults by using four Korean adult male and two female voxel phantoms combined with Monte Carlo simulation techniques. We calculated organ dose conversion coefficients for head, chest, abdomen and pelvis, and chest-abdomen-pelvis scans, and compared the results with the existing data calculated from Caucasian phantoms. We derived representative organ doses for Korean adults using Korean CT dose surveys combined with the dose conversion coefficients. The organ dose conversion coefficients from the Korean adult phantoms were slightly greater than those of the ICRP reference phantoms: up to 13% for the brain doses in head scans and up to 10% for the dose to the small intestine wall in abdominal scans. We derived Korean representative doses to major organs in head, chest, and AP scans using mean CTDIvol values extracted from the Korean nationwide surveys conducted in 2008 and 2017. The Korean-specific organ dose conversion coefficients should be useful to readily estimate organ absorbed doses for Korean adult male and female patients undergoing CT scans.

Review of the risk of cancer following low and moderate doses of sparsely ionising radiation received in early life in groups with individually estimated doses

BACKGROUND

The detrimental health effects associated with the receipt of moderate (0.1-1 Gy) and high (>1 Gy) acute doses of sparsely ionising radiation are well established from human epidemiological studies. There is accumulating direct evidence of excess risk of cancer in a number of populations exposed at lower acute doses or doses received over a protracted period. There is evidence that relative risks are generally higher after radiation exposures in utero or in childhood.

METHODS AND FINDINGS

We reviewed and summarised evidence from 60 studies of cancer or benign neoplasms following low- or moderate-level exposure in utero or in childhood from medical and environmental sources. In most of the populations studied the exposure was predominantly to sparsely ionising radiation, such as X-rays and gamma-rays. There were significant (p < 0.001) excess risks for all cancers, and particularly large excess relative risks were observed for brain/CNS tumours, thyroid cancer (including nodules) and leukaemia.

CONCLUSIONS

Overall, the totality of this large body of data relating to in utero and childhood exposure provides support for the existence of excess cancer and benign neoplasm risk associated with radiation doses < 0.1 Gy, and for certain groups exposed to natural background radiation, to fallout and medical X-rays in utero, at about 0.02 Gy.

Pediatric Nuclear Medicine Examinations and Subsequent Risk of Neoplasm: A Nationwide Population-Based Cohort Study

Objective: To evaluate the association between radiation exposure from repeated nuclear medicine (NM) examinations and the subsequent risk of neoplasm in pediatric patients.

Methods: From 2000 to 2017, participants under 18 years of age who underwent NM scanning were identified using the Health and Welfare Data Science Center (HWDC) dataset, which was extracted from the Taiwan National Health Insurance Research Database (NHIRD). Both the exposed cohort and unexposed subjects were followed up with until the presence of any malignancy arose, including malignant brain, lymphoid and hematopoietic tumors and benign brain or other central nervous tumors.

Results: There were 35,292 patients in the exposed cohort and 141,152 matched subjects in the non-exposed group. The exposed cohort had an overall higher IR (IR: incidence rate, per 100,000 person-years) of any malignancy and benign central nervous tumor than the non-exposed group [IR, 16.9 vs. 1.54; adjusted hazard ratio (HR), 10.9; 95% CI, 6.53–18.2]. Further stratifying the number of NM examinations into 1-2, 3-4, and 5 or more times revealed that the IR of pediatric neoplasms increased gradually with the increased frequency of NM examinations (IR, 11.5; adjusted HR, 7.5; 95% CI, 4.29–13.1; IR, 25.8; adjusted HR, 15.9; 95% CI, 7.00–36.1; IR, 93.8; adjusted HR, 56.4; 95% CI, 28.8–110.3).

Conclusion: NM examination is significantly associated with a higher risk of pediatric neoplasms, according to our population-based data. Thorough radiation protection and dose reduction in pediatric NM procedures should be an issue of concern.

National Trends in Pediatric CT Scans in South Korea: A Nationwide Cohort Study

Purpose

This study evaluated the rates and annual trends of pediatric CT scans in South Korea using a nationwide population-based database.

Materials and Methods

Data regarding pediatric CT scan usage between 2012 and 2017 were retrieved from the health insurance review and assessment service. Data on the age, sex, diagnosis, and the anatomical area of involved patients were also extracted.

Results

A total of 576376 CT examinations were performed among 58527528 children aged below 18 years (9.8 scans/1000 children), and the number of CT examinations per 1000 children was noted to have increased by 23.2% from 9.0 in 2012 to 11.0 in 2017. Specifically, the number of CT examinations increased by 32.9% for the 6–12 years of age group (7.4/1000 to 9.8/1000) and by 34.0% for the 13–18 years of age group (11.4/1000 to 15.3/1000). Moreover, majority of the CT scans were limited to the head (39.1%), followed by the extremities (32.5%) and the abdomen (13.7%). Notably, the number of extremity CT scans increased by 83.6% (2.3/1000 to 4.2/1000), and its proportion as compared to other scans increased from 25.3% to 37.7%.

Conclusion

CT scans in the pediatric population increased continuously from 2012 to 2017 at an annual rate of 4.4%. Therefore, physicians should balance the benefits of CT with its potential harms from associated radiation exposure in pediatric patients.

Impact of Reverse Causation on Estimates of Cancer Risk Associated With Radiation Exposure From Computerized Tomography: A Simulation Study Modeled on Brain Cancer

Use of computed tomography (CT) scanning has increased substantially since its introduction in the 1990s. Several authors have reported increased risk of leukemia and brain tumors associated with radiation exposure from CT scans. However, reverse causation is a concern, particularly for brain cancer; in other words, the CT scan may have been taken because of preexisting cancer and therefore not have been a cause. We assessed the possibility of reverse causation via a simulation study focused on brain tumors, using a simplified version of the data structure for recent CT studies. Five-year-lagged and unlagged analyses implied an observed excess risk per scan up to 70% lower than the true excess risk per scan, particularly when more than 10% of persons with latent cancer had increased numbers of scans or the extra scanning rate after development of latent cancer was greater than 2 scans/year; less extreme values of these parameters imply little risk attenuation. Without a lag and when more than 20% of persons with latent cancer had increased scans-an arguably implausible scenario-the excess risk per scan was increased over the true excess risk per scan by up to 35%-40%. This study suggests that with a realistic lag, reverse causation results in downwardly biased risk, a result of induced classical measurement error, and is therefore unlikely to produce a spurious positive association between cancer and radiation dose from CT scans.

Evaluation of the post-processing algorithms SimGrid and S-Enhance for paediatric intensive care patients and neonates

BACKGROUND

Post-processing software can be used in digital radiography to achieve higher image quality, especially in cases of scattered radiation. SimGrid is a grid-like software based on a Convolutional Neuronal Network that estimates the distribution and degree of scattered radiation in radiographs and thus improves image quality by simulating an anti-scatter grid. S-Enhance is an algorithm programmed to improve contrast visibility of foreign material.

OBJECTIVE

The objective of this study was to evaluate the SimGrid and S-Enhance digital radiography post-processing methods for neonatology and paediatric intensive care.

MATERIALS AND METHODS

Two hundred and ten radiographs from the neonatal (n = 101, 0 to 6 months of age) and paediatric (n = 109, 6 months to 18 years of age) intensive care units performed in daily clinical routine using a mobile digital radiography system were post-processed with one of the algorithms, anonymized and then evaluated comparatively by two experienced paediatric radiologists. For every radiograph, patient data and exposure data were collected and analysed.

RESULTS

Analysis of different radiographs showed that SimGrid significantly improves image quality for patients with a weight above 10 kg (range: 10-30 kg: odds ratio [OR] = 6.683, P < 0.0001), especially regarding the tracheobronchial system, intestinal gas, and bones. Utilizing S-Enhance significantly advances the assessment of foreign material (OR = 136.111, P < 0.0001) and bones (OR = 34.917, P < 0.0001) for children of all ages and weight, whereas overall image quality decreases.

CONCLUSION

SimGrid offers a differentiated spectrum in image improvement for children beyond the neonatal period whereas S-Enhance especially improves visibility of foreign material and bones for all patients.

Young children with a minor traumatic head injury: clinical observation or CT scan?

Currently, in young children with minor traumatic head injuries (MTHI) classified as intermediate risk (IR), PECARN recommends clinical observation over computer tomography (CT) scan depending on provider comfort, although both options being possible. In this study, we describe clinicians' choice and which factors were associated with this decision. This was a planned sub-study of a prospective multicenter observational study that enrolled 1006 children younger than 18 years with MTHI who presented to six emergency departments in The Netherlands. Of those, 280 children classified as IR group fulfilling one or more minor criteria, leaving the clinician with the choice between clinical observation and a CT scan. In our cohort, 228/280 (81%) children were admitted for clinical observation, 15/280 (5.4%) received a CT scan, 6/280 (2.1%) received a CT scan and were admitted for observation, and 31/280 (11%) children were discharged from the emergency department without any intervention. Three objective factors were associated with a CT scan, namely age above 2 years, the presence of any loss of consciousness (LOC), and presentation on weekend days.

CONCLUSION

In children with MTHI in an IR group, clinicians prefer clinical observation above performing a CT scan. Older age, day of presentation, and any loss of consciousness are factors associated with a CT scan.

WHAT IS KNOWN

• Clinical decision rules have been developed in the management of children of different risk groups with minor traumatic head injury (MTHI). • According to the Dutch national, clinical decision rules in children under 6 years of age up to 50% of children classify as intermediate risk (IR) and clinicians may choose between clinical observation and computed tomography (CT).

WHAT IS NEW

• In this IR group, clinical observation is chosen in 81% children with MTHI. • In the subgroup where clinicians performed a CT scan, children were older and presented more frequently on a weekend day, and more frequently consciousness was lost.

Sinogenic Orbital Complications

BACKGROUND

The term "orbital complication" does not designate an independent nosological entity, but is rather a collective designation for diseases or disease effects that involve the orbit and its internal structures by extension from outside. In general, their most prominent manifestation is swelling of the orbital soft tissues, usually unilaterally. The incidence of sinogenic orbital complications is approximately 1.6 per 100 000 children and 0.1 per 100 000 adults per year.

METHODS

This review is based on publications retrieved by a selective search of the literature on the epidemiology, diagnosis, and treatment of sinogenic orbital complications.

RESULTS

Acute sinusitis is the most common cause of orbital complications. These are diseases of the orbit with potentially serious consequences for the eye and the risk of intracranial complications such as cavernous sinus thrombosis, meningitis, or brain abscess. Aside from acute sinusitis, many other infectious and non-infectious diseases can extend to and involve the orbit. Because of the complexity and severity of the condition, its diagnosis and treatment are always an interdisciplinary matter. The treatment is primarily conservative, under observation in a hospital, and generally consists of the treatment of acute sinusitis with measures to combat edema along with the administration of broad-spectrum antibiotics. Surgical intervention is needed in severe cases or if there is an abscess. An endonasal approach is usually used for drainage.

CONCLUSION

In 95-98% of cases in stages I-IV, healing is complete and without further sequelae. Even if vision is affected preoperatively, it usually recovers fully when therapy is appropriate. Approximately 15% of the patients who undergo surgery need more than one operative procedure.