AXIN1 bi-allelic variants disrupting the C-terminal DIX domain cause craniometadiaphyseal osteosclerosis with hip dysplasia.

Sclerosing skeletal dysplasias result from an imbalance between bone formation and resorption. We identified three homozygous, C-terminally truncating AXIN1 variants in seven individuals from four families affected by macrocephaly, cranial hyperostosis, and vertebral endplate sclerosis. Other frequent findings included hip dysplasia, heart malformations, variable developmental delay, and hematological anomalies. In line with AXIN1 being a central component of the ß-catenin destruction complex, analyses of primary and genome-edited cells harboring the truncating variants revealed enhanced basal canonical Wnt pathway activity. All three AXIN1-truncating variants resulted in reduced protein levels and impaired AXIN1 polymerization mediated by its C-terminal DIX domain but partially retained Wnt-inhibitory function upon overexpression. Addition of a tankyrase inhibitor attenuated Wnt overactivity in the AXIN1-mutant model systems. Our data suggest that AXIN1 coordinates the action of osteoblasts and osteoclasts and that tankyrase inhibitors can attenuate the effects of AXIN1 hypomorphic variants.

Patient safety incidents in paediatric radiology: how to care for the professional?

Patient safety incidents in paediatric radiology have profound impacts not only on the patient and their family, but also on the well-being and professional practice of healthcare professionals. These incidents, which range from procedural and diagnostic incidents to serious adverse events leading to harm or even death of the patient, may evoke feelings of distress, guilt, and anxiety among paediatric radiologists (in-training), ultimately affecting their confidence and ability to deliver high-quality care. Recognizing the importance of addressing these challenges, healthcare organizations should implement strategies to support professionals in coping with and learning from these incidents. By fostering a culture of open communication, providing access to peer support, and offering structured debriefing and educational opportunities, healthcare institutions can help mitigate the psychological toll of patient safety incidents and promote resilience among their staff. This article examines the multifaceted impacts of patient safety incidents on paediatric radiologists (in-training) and their staff and outlines effective approaches for handling these incidents to support professional well-being and enhance patient safety.

Collaborating with non-radiological clinical colleagues.

Paediatric radiology is a challenging and intriguing subspecialty, dealing with children, guardians and non-radiological clinical colleagues. Paediatric radiologists are routinely in contact with numerous paediatric and surgical subspecialties, all having different needs, perceptions, prioritisations and expectations. Moreover, the radiologist is part of the team of radiographers, sonographers, nurses and secretaries, assisted by appropriate equipment and electronic tools. The framework of good collaboration to ensure safety and effectiveness for the imaged child is a shared responsibility among all medical practitioners involved. Communication in routine practice has many forms and includes appropriately filled radiology requests in accordance to the patient's medical records, routine and timely production of structured, problem-solving radiology reports, face-to-face or electronic-assisted communications and discussions on a pre-defined framework, mutually-agreed and evidence-based protocols adjusted to local availability, skills and national and international guidelines. Mutual understanding of advantages and limitations of imaging is paramount. Well-meant discussions, professionalism and empathy should promote soft skills, bidirectional communication and good collaboration for the benefit of added-value paediatric radiology. International societies, health authorities, medical directors and senior consultants have the responsibility to suggest and safeguard frameworks and recommendations. Regular multidisciplinary meetings and multidisciplinary research projects under openness, honesty and transparency are pathways favouring good collaboration.

18 F-FDG-PET/CT imaging in diagnostic workup of pediatric precursor B-cell lymphoblastic lymphoma.

18 F-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) imaging is currently not used in standard diagnostics for B-cell precursor lymphoblastic lymphoma (BCP-LBL), and it is unknown whether PET/CT imaging would lead to agreement between detection of lesions with the gold standard imaging methods. Therefore, we performed a retrospective cohort study in which we included 32 pediatric BCP-LBL patients and determined localizations by reviewing local imaging reports. There was a disagreement between protocol-based imaging and PET/CT in 59% of the patients, and the discrepancies mostly comprise of additional lesions detected with PET/CT, typically in lymph node and bone or the absence of bone marrow involvement with PET/CT. If PET/CT was leading in determining definite stage of disease, this would lead to a different stage and therapy branch in 31% and 28% of the patients, respectively.

Pediatric body composition based on automatic segmentation of computed tomography scans: a pilot study.

BACKGROUND: Body composition during childhood may predispose to negative health outcomes later in life. Automatic segmentation may assist in quantifying pediatric body composition in children. OBJECTIVE: To evaluate automatic segmentation for body composition on pediatric computed tomography (CT) scans and to provide normative data on muscle and fat areas throughout childhood using automatic segmentation. MATERIALS AND METHODS: In this pilot study, 537 children (ages 1-17 years) who underwent abdominal CT after high-energy trauma at a Dutch tertiary center (2002-2019) were retrospectively identified. Of these, the CT images of 493 children (66% boys) were used to establish normative data. Muscle (psoas, paraspinal and abdominal wall) and fat (subcutaneous and visceral) areas were measured at the third lumbar vertebral (L3) level by automatic segmentation. A representative subset of 52 scans was also manually segmented to evaluate the performance of automatic segmentation. RESULTS: For manually-segmented versus automatically-segmented areas (52 scans), mean Dice coefficients were high for muscle (0.87-0.90) and subcutaneous fat (0.88), but lower for visceral fat (0.60). In the control group, muscle area was comparable for both sexes until the age of 13 years, whereafter, boys developed relatively more muscle. From a young age, boys were more prone to visceral fat storage than girls. Overall, boys had significantly higher visceral-to-subcutaneous fat ratios (median 1.1 vs. 0.6, P<0.01) and girls higher fat-to-muscle ratios (median 1.0 vs. 0.7, P<0.01). CONCLUSION: Automatic segmentation of L3-level muscle and fat areas allows for accurate quantification of pediatric body composition. Using automatic segmentation, the development in muscle and fat distribution during childhood (in otherwise healthy) Dutch children was demonstrated.

MRI Characteristics of Pediatric Renal Tumors: A SIOP-RTSG Radiology Panel Delphi Study.

BACKGROUND: The SIOP-Renal Tumor Study Group (RTSG) does not advocate invasive procedures to determine histology before the start of therapy. This may induce misdiagnosis-based treatment initiation, but only for a relatively small percentage of approximately 10% of non-Wilms tumors (non-WTs). MRI could be useful for reducing misdiagnosis, but there is no global consensus on differentiating characteristics. PURPOSE: To identify MRI characteristics that may be used for discrimination of newly diagnosed pediatric renal tumors. STUDY TYPE: Consensus process using a Delphi method. POPULATION: Not applicable. FIELD STRENGTH/SEQUENCE: Abdominal MRI including T1- and T2-weighted imaging, contrast-enhanced MRI, and diffusion-weighted imaging at 1.5 or 3 T. ASSESSMENT: Twenty-three radiologists from the SIOP-RTSG radiology panel with ≥5 years of experience in MRI of pediatric renal tumors and/or who had assessed ≥50 MRI scans of pediatric renal tumors in the past 5 years identified potentially discriminatory characteristics in the first questionnaire. These characteristics were scored in the subsequent second round, consisting of 5-point Likert scales, ranking- and multiple choice questions. STATISTICAL TESTS: The cut-off value for consensus and agreement among the majority was ≥75% and ≥60%, respectively, with a median of ≥4 on the Likert scale. RESULTS: Consensus on specific characteristics mainly concerned the discrimination between WTs and non-WTs, and WTs and nephrogenic rest(s) (NR)/nephroblastomatosis. The presence of bilateral lesions (75.0%) and NR/nephroblastomatosis (65.0%) were MRI characteristics indicated as specific for the diagnosis of a WT, and 91.3% of the participants agreed that MRI is useful to distinguish NR/nephroblastomatosis from WT. Furthermore, all participants agreed that age influenced their prediction in the discrimination of pediatric renal tumors. DATA CONCLUSION: Although the discrimination of pediatric renal tumors based on MRI remains challenging, this study identified some specific characteristics for tumor subtypes, based on the shared opinion of experts. These results may guide future validation studies and innovative efforts. LEVEL OF EVIDENCE: 3 Technical Efficacy Stage: 3.

The phenotypic and genetic spectrum of patients with heterozygous mutations in cyclin M2 (CNNM2).

Hypomagnesemia, seizures, and intellectual disability (HSMR) syndrome is a rare disorder caused by mutations in the cyclin M2 (CNNM2) gene. Due to the limited number of cases, extensive phenotype analyses of these patients have not been performed, hindering early recognition of patients. In this study, we established the largest cohort of HSMR to date, aiming to improve recognition and diagnosis of this complex disorder. Eleven novel variants in CNNM2 were identified in nine single sporadic cases and in two families with suspected HSMR syndrome. 25 Mg2+ uptake assays demonstrated loss-of-function in seven out of nine variants in CNNM2. Interestingly, the pathogenic mutations resulted in decreased plasma membrane expression. The phenotype of those affected by pathogenic CNNM2 mutations was compared with five previously reported cases of HSMR. All patients suffered from hypomagnesemia (0.44-0.72 mmol/L), which could not be fully corrected by Mg2+ supplementation. The majority of patients (77%) experienced generalized seizures and exhibited mild to moderate intellectual disability and speech delay. Moreover, severe obesity was present in most patients (89%). Our data establish hypomagnesemia, seizures, intellectual disability, and obesity as hallmarks of HSMR syndrome. The assessment of these major features offers a straightforward tool for the clinical diagnosis of HSMR.

Whole-body MRI versus an [18F]FDG-PET/CT-based reference standard for early response assessment and restaging of paediatric Hodgkin's lymphoma: a prospective multicentre study.

OBJECTIVES: To compare WB-MRI with an [18F]FDG-PET/CT-based reference for early response assessment and restaging in children with Hodgkin's lymphoma (HL). METHODS: Fifty-one children (ages 10-17) with HL were included in this prospective, multicentre study. All participants underwent WB-MRI and [18F]FDG-PET/CT at early response assessment. Thirteen of the 51 patients also underwent both WB-MRI and [18F]FDG-PET/CT at restaging. Two radiologists independently evaluated all WB-MR images in two separate readings: without and with DWI. The [18F]FDG-PET/CT examinations were evaluated by a nuclear medicine physician. An expert panel assessed all discrepancies between WB-MRI and [18F]FDG-PET/CT to derive the [18F]FDG-PET/CT-based reference standard. Inter-observer agreement for WB-MRI was calculated using kappa statistics. Concordance, PPV, NPV, sensitivity and specificity for a correct assessment of the response between WB-MRI and the reference standard were calculated for both nodal and extra-nodal disease presence and total response evaluation. RESULTS: Inter-observer agreement of WB-MRI including DWI between both readers was moderate (κ 0.46-0.60). For early response assessment, WB-MRI DWI agreed with the reference standard in 33/51 patients (65%, 95% CI 51-77%) versus 15/51 (29%, 95% CI 19-43%) for WB-MRI without DWI. For restaging, WB-MRI including DWI agreed with the reference standard in 9/13 patients (69%, 95% CI 42-87%) versus 5/13 patients (38%, 95% CI 18-64%) for WB-MRI without DWI. CONCLUSIONS: The addition of DWI to the WB-MRI protocol in early response assessment and restaging of paediatric HL improved agreement with the [18F]FDG-PET/CT-based reference standard. However, WB-MRI remained discordant in 30% of the patients compared to standard imaging for assessing residual disease presence. KEY POINTS: • Inter-observer agreement of WB-MRI including DWI between both readers was moderate for (early) response assessment of paediatric Hodgkin's lymphoma. • The addition of DWI to the WB-MRI protocol in early response assessment and restaging of paediatric Hodgkin's lymphoma improved agreement with the [18F]FDG-PET/CT-based reference standard. • WB-MRI including DWI agreed with the reference standard in respectively 65% and 69% of the patients for early response assessment and restaging.

Whole-body MRI versus an FDG-PET/CT-based reference standard for staging of paediatric Hodgkin lymphoma: a prospective multicentre study.

OBJECTIVES: To assess the concordance of whole-body MRI (WB-MRI) and an FDG-PET/CT-based reference standard for the initial staging in children with Hodgkin lymphoma (HL) METHODS: Children with newly diagnosed HL were included in this prospective, multicentre, international study and underwent WB-MRI and FDG-PET/CT at staging. Two radiologists and a nuclear medicine physician independently evaluated all images. Discrepancies between WB-MRI and FDG-PET/CT were assessed by an expert panel. All FDG-PET/CT errors were corrected to derive the FDG-PET/CT-based reference standard. The expert panel corrected all reader errors in the WB-MRI DWI dataset to form the intrinsic MRI data. Inter-observer agreement for WB-MRI DWI was calculated using overall agreement, specific agreements and kappa statistics. Concordance for correct classification of all disease sites and disease stage between WB-MRI (without DWI, with DWI and intrinsic WB-MRI DWI) and the reference standard was calculated as primary outcome. Secondary outcomes included positive predictive value, negative predictive value and kappa statistics. Clustering within patients was accounted for using a mixed-effect logistic regression model with random intercepts and a multilevel kappa analysis. RESULTS: Sixty-eight children were included. Inter-observer agreement between WB-MRI DWI readers was good for disease stage (κ = 0.74). WB-MRI DWI agreed with the FDG-PET/CT-based reference standard for determining disease stage in 96% of the patients versus 88% for WB-MRI without DWI. Agreement between WB-MRI DWI and the reference standard was excellent for both nodal (98%) and extra-nodal (100%) staging. CONCLUSIONS: WB-MRI DWI showed excellent agreement with the FDG-PET/CT-based reference standard. The addition of DWI to the WB-MRI protocol improved the staging agreement. KEY POINTS: • This study showed excellent agreement between WB-MRI DWI and an FDG-PET/CT-based reference standard for staging paediatric HL. • Diffusion-weighted imaging is a useful addition to WB-MRI in staging paediatric HL. • Inter-observer agreement for WB-MRI DWI was good for both nodal and extra-nodal staging and determining disease stage.

Body composition of patients with neuroblastoma using computed tomography.

BACKGROUND: Computed tomography (CT) is often used to investigate muscle and fat mass in adult patients with cancer. However, this method has rarely been used in the pediatric cancer population. The present retrospective study aimed to investigate changes in body composition using CT during treatment in children with neuroblastoma. PROCEDURE: CT images of 29 patients with high-risk neuroblastoma were retrospectively analyzed at diagnosis and longitudinally during treatment. The cross-sectional area of skeletal muscle, intermuscular adipose tissue (IMAT), visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) and skeletal muscle density at the level of the third lumbar vertebra were examined. To correct for height, cross-sectional areas were divided by height in meters squared. A linear mixed model was estimated to investigate changes in body composition over time. RESULTS: A small increase in skeletal muscle (p = .029), skeletal muscle density (p = .002), and IMAT (p < .001) was found. Furthermore, a rapid increase in VAT (p < .001) and SAT (p = .001) was seen early during treatment with the highest volumes after six cycles of chemotherapy. CONCLUSIONS: CT scans obtained during standard care provide insight into the direction and timing of changes in skeletal muscle and different types of adipose tissue in childhood cancer patients. Future research is needed regarding the consequences of the rapid increase of VAT and SAT early during treatment.

Diagnostic accuracy of image-guided core needle biopsy of non-central nervous system tumors in children.

BACKGROUND AND AIMS: Core needle biopsies (CNB) are less invasive, cause less morbidity, and have lower costs than open biopsies (OB). However, the number of studies reporting CNB accuracy in pediatric tumors is limited and series are small. The aim of this study is to investigate if CNB diagnosis is concordant with the final diagnosis in pediatric solid non-central nervous system (CNS) tumors. METHODS: Data from all patients treated in a single center between November 2014 and December 2019 were collected from the national pathology database and from local medical records. Data collection included age, sex, CNB diagnosis, final diagnosis, number of cores obtained, number of cores used for histology, cumulative core length, greatest dimension of the lesion, lesion volume, and complications. RESULTS: Out of 361 CNB, 95.6% (345/361) provided a diagnosis. A resection or follow-up biopsy was performed in 201 cases. The final diagnosis was concordant with the CNB in 100% (201/201) of cases. The age, number of cores used for histology, and the greatest dimension of the lesion did not significantly differ between diagnostic and nondiagnostic CNB. The cumulative core length of diagnostic CNB was significantly higher than in the nondiagnostic group (24.72 mm vs. 13.37 mm, p-value .022). Complications occurred in 2.1% (7/337) of CNB procedures. Molecular analysis was successful in 228/233 (98%) of cases in which it was performed. CONCLUSIONS: CNB diagnosis is highly concordant with the final diagnosis and the diagnostic rate is high. The complication rate in CNB is low.

Measurements of cervical lymph nodes in children on computed tomography.

BACKGROUND: No normal measurements or specific size criteria have been described for cervical lymph nodes in children. OBJECTIVE: To determine the normal measurements of cervical lymph nodes in children on CT. MATERIALS AND METHODS: We included 142 children (ages 1-17 years) who underwent cervical CT examination after high-energy trauma. We evaluated axial and coronal 2-mm reconstructions for lymph nodes at six cervical levels. For the largest lymph node at each level, we measured diameters in both the long and short axial axes and the long coronal axis. RESULTS: A total of 733 lymph nodes were measured in 142 children (62% boys, 38% girls). The greatest measured diameters were 14 mm for the short axis in the axial plane, 24 mm for the long axis in the axial plane and 28 mm for the long axis in the coronal plane. The Pearson correlation coefficient for age and lymph node size at Levels IV-VI was in the range of 0.19-0.47. CONCLUSION: Lymph nodes with an axial short-axis diameter exceeding 15 mm for Level II and 10 mm for all other cervical levels are uncommon in otherwise healthy children.

Abdominal lymph node size in children at computed tomography.

BACKGROUND: Lymph node enlargement is commonly used to indicate abnormality. OBJECTIVE: To evaluate the normal size and prevalence of abdominal lymph nodes in children at CT. MATERIALS AND METHODS: In this retrospective study, we included a total of 152 children ages 1-17 years who underwent abdominal CT examination after high-energy trauma. We measured abdominal lymph nodes in five lymph node stations (inguinal, iliac, para-aortic, hepatic and mesenteric). For the largest lymph node in each level, we measured long- and short-axis diameters in both the axial and coronal planes. We then calculated distribution parameters, correlation coefficients between lymph node size and age, and reference intervals. RESULTS: The prevalence of detectable lymph nodes was high for the inguinal (100%), iliac (98%), para-aortic (97%) and mesenteric (99%) stations and lower for the hepatic station (32%). Lymph node size showed small to medium significant correlations (ranging from 0.21 to 0.50) with age. When applying the Lugano criteria and RECIST (Response Criteria in Solid Tumors), 29 children (19%) would have had one or more enlarged abdominal lymph nodes. CONCLUSION: The results of this study provide normative data of abdominal lymph node size in children. The current adult guidelines for enlarged lymph nodes seem adequate for most children with the exception of young adolescents, in which larger lymph nodes were relatively common, particularly in the inguinal region.

Whole-body magnetic resonance imaging in pediatric oncology - recommendations by the Oncology Task Force of the ESPR.

The purpose of this recommendation of the Oncology Task Force of the European Society of Paediatric Radiology (ESPR) is to indicate reasonable applications of whole-body MRI in children with cancer and to address useful protocols to optimize workflow and diagnostic performance. Whole-body MRI as a radiation-free modality has been increasingly performed over the last two decades, and newer applications, as in screening of children with germ-line mutation cancer-related gene defects, are now widely accepted. We aim to provide a comprehensive outline of the diagnostic value for use in daily practice. Based on the results of our task force session in 2018 and the revision in 2019 during the ESPR meeting, we summarized our group's experiences in whole-body MRI. The lack of large evidence by clinical studies is challenging when focusing on a balanced view regarding the impact of whole-body MRI in pediatric oncology. Therefore, the final version of this recommendation was supported by the members of Oncology Task Force.

Bone-marrow derived mesenchymal stromal cells infusion in therapy refractory juvenile idiopathic arthritis patients.

OBJECTIVES: To compare the total number of adverse events (AEs) before and after mesenchymal stromal cell (MSC) infusion in refractory JIA and to evaluate its effectiveness. METHODS: Single-centre Proof of Mechanism Phase Ib, open label intervention study in JIA patients previously failing all biologicals registered for their diagnosis. Six patients received 2 million/kg intravenous infusions of allogeneic bone-marrow derived MSC. In case of ACR-Ped30-response but subsequent loss of response one and maximal two repeated infusions are allowed. RESULTS: Six JIA patients with 9.2 years median disease duration, still active arthritis and damage were included. All had failed methotrexate, corticosteroids and median five different biologicals. MSC were administered twice in three patients. No acute infusion reactions were observed and a lower post-treatment than pre-treatment incidence in AEs was found. The one systemic onset JIA (sJIA) patient had again an evolving macrophage activation syndrome, 9 weeks after tocilizumab discontinuation and 7 weeks post-MSC infusion. Statistically significant decreases were found 8 weeks after one MSC infusion in VAS well-being (75-56), the JADAS-71 (24.5-11.0) and the cJADAS10 (18.0-10.6). CONCLUSION: MSC infusions in six refractory JIA patients were safe, although in sJIA stopping the 'failing' biologic treatment carries a risk of a MAS flare, as the drug might still suppress the systemic features. TRIAL REGISTRATION: Trial register.nl, http://https://www.trialregister.nl, NTR4146.

Predictive value of interim positron emission tomography in diffuse large B-cell lymphoma: a systematic review and meta-analysis.

PURPOSE: Diffuse large B-cell lymphoma (DLBCL) represents the most common subtype of non-Hodgkin lymphoma. Most relapses occur in the first 2 years after diagnosis. Early response assessment with 18F-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET) may facilitate early change of treatment, thereby preventing ineffective treatment and unnecessary side effects. We aimed to assess the predictive value of visually-assessed interim 18F-FDG PET on progression-free survival (PFS) or event-free survival (EFS) in DLBCL patients treated with first-line immuno-chemotherapy regimens. METHODS: For this systematic review and meta-analysis Pubmed, Embase, and the Cochrane Library were searched until July 11, 2017. Prospective and retrospective studies investigating qualitative interim PET response assessment without treatment adaptation based on the interim PET result were eligible. The primary outcome was two-year PFS or EFS. Prognostic and diagnostic measures were extracted and analysed with pooled hazard ratios and Hierarchical Summary Receiver Operator Characteristic Curves, respectively. Meta-regression was used to study covariate effects. RESULTS: The pooled hazard ratio for 18 studies comprising 2,255 patients was 3.13 (95%CI 2.52-3.89) with a 95% prediction interval of 1.68-5.83. In 19 studies with 2,366 patients, the negative predictive value for progression generally exceeded 80% (64-95), but sensitivity (33-87), specificity (49-94), and positive predictive values (20-74) ranged widely. CONCLUSIONS: These findings showed that interim 18F-FDG PET has predictive value in DLBCL patients. However, (subgroup) analyses were limited by lack of information and small sample sizes. Some diagnostic test characteristics were not satisfactory, especially the positive predictive value should be improved, before a successful risk stratified treatment approach can be implemented in clinical practice.

Imaging features of extranodal involvement in paediatric Hodgkin lymphoma.

Detecting extranodal disease in paediatric Hodgkin lymphoma is of great importance for both treatment and prognosis. Different imaging techniques can be used to identify these extranodal sites. This pictorial essay provides an overview of imaging features of extranodal disease manifestation in paediatric Hodgkin lymphoma.

The European Society of Paediatric Radiology launches European Diploma in Paediatric Radiology.

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Whole-body MRI reveals high incidence of osteonecrosis in children treated for Hodgkin lymphoma.

Osteonecrosis is a well-recognized complication in patients treated with corticosteroids. The incidence of osteonecrosis in children treated for Hodgkin lymphoma is unknown because prospective whole-body magnetic resonance imaging (MRI) studies are lacking in this patient population. Paediatric patients with newly diagnosed Hodgkin lymphoma who were treated according to a uniform paediatric Hodgkin protocol were eligible for inclusion in this prospective study. Whole-body MRI was performed in all 24 included patients (mean age 15·1 years, 12 girls) both before treatment and after 2 cycles of chemotherapy, and in 16 patients after completion of chemotherapy. Osteonecrosis was identified in 10 patients (41·7%, 95% confidence interval: 22·0-61·4%), with a total of 56 osteonecrotic sites. Osteonecrosis was detected in 8 patients after 2 cycles of OEPA (vincristine, etoposide, prednisone, doxorubicin), and in 2 additional patients after completion of chemotherapy. Epiphyseal involvement of long bones was seen in 4 of 10 children. None of the patients with osteonecrosis had any signs of bone collapse at the times of scanning. Whole-body MRI demonstrates osteonecrosis to be a common finding occurring during therapy response assessment of paediatric Hodgkin lymphoma. Detection of early epiphyseal osteonecrosis could allow for treatment before bone collapse and joint damage may occur.

Trends and patterns of computed tomography scan use among children in The Netherlands: 1990-2012.

OBJECTIVE: To evaluate trends and patterns in CT usage among children (aged 0-17 years) in The Netherlands during the period 1990-2012. METHODS: Lists of electronically archived paediatric CT scans were requested from the Radiology Information Systems (RIS) of Dutch hospitals which reported >10 paediatric CT scans annually in a survey conducted in 2010. Data included patient identification, birth date, gender, scan date and body part scanned. For non-participating hospitals and for years prior to electronic archiving in some participating hospitals, data were imputed by calendar year and hospital type (academic, general with <500 beds, general with ≥ 500 beds). RESULTS: Based on 236,066 CT scans among 146,368 patients performed between 1990 and 2012, estimated annual numbers of paediatric CT scans in The Netherlands increased from 7,731 in 1990 to 26,023 in 2012. More than 70 % of all scans were of the head and neck. During the last decade, substantial increases of more than 5 % per year were observed in general hospitals with fewer than 500 beds and among children aged 10 years or older. CONCLUSION: The estimated number of paediatric CT scans has more than tripled in The Netherlands during the last two decades. KEY POINTS: • Paediatric CT in The Netherlands has tripled during the last two decades. • The number of paediatric CTs increased through 2012 in general hospitals. • Paediatric CTs continued to increase among children aged 10 years or older.