Computed tomographies and cancer risk in children: a literature overview of CT practices, risk estimations and an epidemiologic cohort study proposal

Synchronous retroperitoneal liposarcoma and gastric adenocarcinoma: A rare case report

Multiple primary malignancies can occur as either synchronous or metachronous tumors, particularly in adults. Retroperitoneal liposarcoma is a rare malignancy arising from adipose tissue, while gastric adenocarcinoma is one of the most common neoplasms worldwide. The simultaneous occurrence of these 2 malignancies is extremely rare, with only 1 case reported worldwide. Here, we present the case of a 52-year-old man diagnosed with both retroperitoneal liposarcoma and gastric adenocarcinoma, marking the second reported case in the world.

Cervical Collar Clearance in Obtunded Children Presenting Without a Known Traumatic Mechanism: Is Imaging Necessary?

BACKGROUND

Obtunded pediatric patients are often placed in cervical collars (c-collars) to protect their cervical spine (c-spine) while injury is being ruled out, even without a known traumatic injury. The goal of this study was to determine the necessity of c-collars in this population by determining the rate of c-spine injury among patients with suspected non-traumatic mechanisms of loss of consciousness.

METHODS

A single institution, ten-year retrospective chart review was conducted including all obtunded patients admitted to the Pediatric Intensive Care Unit without a known traumatic event. Patients were categorized into five groups based on etiology of obtundation: respiratory, cardiac, medical/metabolic, neurologic, and other. Comparisons were made between those placed in a c-collar and a control group who were not, using Wilcoxon rank sum test for continuous measures, and Chi-square or Fisher's exact test for categorical measures.

RESULTS

464 patients were included, of which 39 (8.41%) were placed in a c-collar. There was a significant difference in whether a patient was placed in a c-collar based on diagnosis category (p < 0.001). Those placed in a-c-collar were more likely to undergo imaging studies than the control group (p < 0.001). The overall incidence of c-spine injury in this patient population in our study was zero.

CONCLUSION

Cervical collar placement and radiographic evaluation is not necessary in obtunded pediatric patients who present without a known traumatic mechanism as the overall risk of injury is low. Consideration for collar placement should be given in cases when trauma cannot be definitively ruled out at initial evaluation.

LEVELS OF EVIDENCE

III.

The Prognostic Value of Ultrasound Findings in Preoperatively Distinguishing between Uncomplicated and Complicated Types of Pediatric Acute Appendicitis Based on Correlation with Intraoperative and Histopathological Findings

OBJECTIVE

This study compares the preoperative ultrasound findings of all children with a clinical picture of acute appendicitis on the basis of intraoperative and histopathological findings to assess the feasibility of this approach in preoperatively distinguishing between uncomplicated and complicated cases.

METHODS

This retrospective study includes 224 pediatric patients who underwent ultrasound prior to appendectomy at our institution between January 2016 and February 2022. Logistic regression analysis was used to investigate the association between sonographic and intraoperative histopathological findings.

RESULTS

Of the 224 participants, 61.1% were intraoperatively diagnosed with uncomplicated appendicitis (59.8% male). Multivariate logistic regression analysis revealed that patients with a higher appendiceal diameter, presence of appendicolith, and peritonitis were more likely to suffer from complicated appendicitis. Finally, the common anatomical position of the appendix and an appendiceal diameter greater than 6 mm had the highest sensitivity (94.6% and 94.5%, respectively) for predicting complicated appendicitis, with the most specific (99.3%) sonographic finding being the existence of an abscess.

CONCLUSIONS

Preoperative abdominal ultrasound in children with a clinical diagnosis of acute appendicitis can distinguish between uncomplicated and complicated appendicitis in most cases of pediatric appendicitis. A higher appendiceal diameter, the presence of appendicolith, and peritonitis are parameters noted by ultrasound that strongly predict complicated appendicitis.

Identification of Genetic Predispositions Related to Ionizing Radiation in Primary Human Skin Fibroblasts From Survivors of Childhood and Second Primary Cancer as Well as Cancer-Free Controls: Protocol for the Nested Case-Control Study KiKme

BACKGROUND

Therapy for a first primary neoplasm (FPN) in childhood with high doses of ionizing radiation is an established risk factor for second primary neoplasms (SPN). An association between exposure to low doses and childhood cancer is also suggested; however, results are inconsistent. As only subgroups of children with FPNs develop SPNs, an interaction between radiation, genetic, and other risk factors is presumed to influence cancer development.

OBJECTIVE

Therefore, the population-based, nested case-control study KiKme aims to identify differences in genetic predisposition and radiation response between childhood cancer survivors with and without SPNs as well as cancer-free controls.

METHODS

We conducted a population-based, nested case-control study KiKme. Besides questionnaire information, skin biopsies and saliva samples are available. By measuring individual reactions to different exposures to radiation (eg, 0.05 and 2 Gray) in normal somatic cells of the same person, our design enables us to create several exposure scenarios for the same person simultaneously and measure several different molecular markers (eg, DNA, messenger RNA, long noncoding RNA, copy number variation).

RESULTS

Since 2013, 101 of 247 invited SPN patients, 340 of 1729 invited FPN patients, and 150 of 246 invited cancer-free controls were recruited and matched by age and sex. Childhood cancer patients were additionally matched by tumor morphology, year of diagnosis, and age at diagnosis. Participants reported on lifestyle, socioeconomical, and anthropometric factors, as well as on medical radiation history, health, and family history of diseases (n=556). Primary human fibroblasts from skin biopsies of the participants were cultivated (n=499) and cryopreserved (n=3886). DNA was extracted from fibroblasts (n=488) and saliva (n=510).

CONCLUSIONS

This molecular-epidemiological study is the first to combine observational epidemiological research with standardized experimental components in primary human skin fibroblasts to identify genetic predispositions related to ionizing radiation in childhood and SPNs. In the future, fibroblasts of the participants will be used for standardized irradiation experiments, which will inform analysis of the case-control study and vice versa. Differences between participants will be identified using several molecular markers. With its innovative combination of experimental and observational components, this new study will provide valuable data to forward research on radiation-related risk factors in childhood cancer and SPNs.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/32395.

Epidemiological studies of CT scans and cancer risk: the state of the science

20 years ago, 3 manuscripts describing doses and potential cancer risks from CT scans in children raised awareness of a growing public health problem. We reviewed the epidemiological studies that were initiated in response to these concerns that assessed cancer risks from CT scans using medical record linkage. We evaluated the study methodology and findings and provide recommendations for optimal study design for new efforts. We identified 17 eligible studies; 13 with published risk estimates, and 4 in progress. There was wide variability in the study methodology, however, which made comparison of findings challenging. Key differences included whether the study focused on childhood or adulthood exposure, radiosensitive outcomes (e.g. leukemia, brain tumors) or all cancers, the exposure metrics (e.g. organ doses, effective dose or number of CTs) and control for biases (e.g. latency and exclusion periods and confounding by indication). We were able to compare results for the subset of studies that evaluated leukemia or brain tumors. There were eight studies of leukemia risk in relation to red bone marrow (RBM) dose, effective dose or number of CTs; seven reported a positive dose-response, which was statistically significant (p < 0.05) in four studies. Six of the seven studies of brain tumors also found a positive dose-response and in five, this was statistically significant. Mean RBM dose ranged from 6 to 12 mGy and mean brain dose from 18 to 43 mGy. In a meta-analysis of the studies of childhood exposure the summary ERR/100 mGy was 1.78 (95%CI: 0.01-3.53) for leukemia/myelodisplastic syndrome (n = 5 studies) and 0.80 (95%CI: 0.48-1.12) for brain tumors (n = 4 studies) (p-heterogeneity >0.4). Confounding by cancer pre-disposing conditions was unlikely in these five studies of leukemia. The summary risk estimate for brain tumors could be over estimated, however, due to reverse causation. In conclusion, there is growing evidence from epidemiological data that CT scans can cause cancer. The absolute risks to individual patients are, however, likely to be small. Ongoing large multicenter cohorts and future pooling efforts will provide more precise risk quantification.

The Diagnostic Accuracy of Noninvasive Methods to Measure the Intracranial Pressure: A Systematic Review and Meta-analysis

BACKGROUND

Although invasive monitoring is the standard method for intracranial pressure (ICP) measurement, it is not without potential for serious complications. Noninvasive methods have been proposed as alternatives to invasive ICP monitoring. The study aimed to investigate the diagnostic accuracy of the currently available noninvasive methods for intracranial hypertension (ICH) monitoring.

METHODS

We searched 5 databases for articles evaluating the diagnostic accuracy of noninvasive methods in diagnosing ICH in PubMed, Institute of Science Index, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), and Embase. The quantitative analysis was conducted if there were at least 2 studies evaluating a specific method. The accuracy measures included the sensitivity, specificity, likelihood ratios, and diagnostic odds ratio.

RESULTS

We included 134 articles. Ultrasonographic optic nerve sheath diameter (US ONSD) had high diagnostic accuracy (estimated sensitivity of 90%; 95% confidence interval [CI], 87-92, estimated specificity of 88%; 95% CI, 84-91) while the magnetic resonance imaging (MRI) ONSD had estimated sensitivity of 77%; 95% CI, 64-87 and estimated specificity of 89%; 95% CI, 84-93, and computed tomography (CT) ONSD had estimated sensitivity of 93%; 95% CI, 90-96 and estimated specificity of 79%; 95% CI, 56-92. All MRI signs had a very high estimated specificity ranging from 90% to 99% but a low estimated sensitivity except for sinus stenosis which had high estimated sensitivity as well as specificity (90%; 95% CI, 75-96 and 96%; 95% CI, 91-99, respectively). Among the physical examination signs, pupillary dilation had a high estimated specificity (86%; 95% CI, 76-93). Other diagnostic tests to be considered included pulsatility index, papilledema, transcranial Doppler, compression or absence of basal cisterns, and ≥10 mm midline shift. Setting the cutoff value of ICH to ≥20 mm Hg instead of values <20 mm Hg was associated with higher sensitivity. Moreover, if the delay between invasive and noninvasive methods was within 1 hour, the MRI ONSD and papilledema had a significantly higher diagnostic accuracy compared to the >1 hour subgroup.

CONCLUSIONS

Our study showed several promising tools for diagnosing ICH. Moreover, we demonstrated that using multiple, readily available, noninvasive methods is better than depending on a single sign such as physical examination or CT alone.

Evaluation of Organ Dose and Image Quality Metrics of Pediatric CT Chest-Abdomen-Pelvis (CAP) Examination: An Anthropomorphic Phantom Study

The aim of this study is to investigate the impact of CT acquisition parameter setting on organ dose and its influence on image quality metrics in pediatric phantom during CT examination. The study was performed on 64-slice multidetector CT scanner (MDCT) Siemens Definition AS (Siemens Sector Healthcare, Forchheim, Germany) using various CT CAP protocols (P1–P9). Tube potential for P1, P2, and P3 protocols were fixed at 100 kVp while P4, P5, and P6 were fixed at 80 kVp with used of various reference noise values. P7, P8, and P9 were the modification of P1 with changes on slice collimation, pitch factor, and tube current modulation (TCM), respectively. TLD-100 chips were inserted into the phantom slab number 7, 9, 10, 12, 13, and 14 to represent thyroid, lung, liver, stomach, gonads, and skin, respectively. The image quality metrics, signal to noise ratio (SNR) and contrast to noise ratio (CNR) values were obtained from the CT console. As a result, this study indicates a potential reduction in the absorbed dose up to 20% to 50% along with reducing tube voltage, tube current, and increasing the slice collimation. There is no significant difference (p > 0.05) observed between the protocols and image metrics.

Value of using adaptive statistical iterative reconstruction-V (ASIR-V) technology in pediatric head CT dose reduction

Background

With widespread use of pediatric head CT, it is critically important to protect patients from radiation hazards, using reduced dose CT techniques. In this regard, adaptive statistical iterative reconstruction-V (ASIR-V) algorithm can decrease image noise, generating CT images of reasonable diagnostic quality with less radiation. The objective of this study was radiation dose assessment, quantitative and qualitative evaluation of reduced dose pediatric head CT using ASIR-V 60% and 80% reconstruction.

Results

Retrospective analysis was performed on two groups of pediatric head CT examinations, a reduced dose CT examination group with ASIR-V reconstruction (ASIR group) (n = 27) and a standard dose CT examination group without ASIR reconstruction (non-ASIR group) (n = 14). The average effective dose (ED) of ASIR group was significantly lower than that of the non-ASIR group (1.04 ± 0.1 mS vs 3.48 ± 0.45 mS; p = 0.001). Quantitative analysis revealed comparable results of signal to noise ratio (SNR) and contrast to noise ratio (CNR) of ASIR and non-ASIR groups (p > 0.05). Qualitative evaluation of resulting images by two readers revealed comparable results of both ASIR and non-ASIR groups (p > 0.05) with excellent inter-reader agreement (κ = 0.97). Both quantitative and qualitative assessment demonstrated better ASIR-V 80% than ASIR-V 60% reconstructed images.

Conclusion

ASIR-V algorithm is a promising technology for effective dose reduction of pediatric head CT with preservation of diagnostic image quality.

Clinical pediatric positron emission tomography/magnetic resonance program: a guide to successful implementation

Children with malignancies undergo recurrent imaging as part of tumor diagnosis, staging and therapy response assessment. Simultaneous positron emission tomography (PET) and magnetic resonance (MR) allows for decreased radiation exposure and acts as a one-stop shop for disease in which MR imaging is required. Nevertheless, PET/MR is still less readily available than PET/CT across institutions. This article serves as a guide to successful implementation of a clinical pediatric PET/MR program based on our extensive clinical experience. Challenges include making scanners more affordable and increasing patient throughput by decreasing total scan time. With improvements in workflow and robust acquisition protocols, PET/MR imaging is expected to play an increasingly important role in pediatric oncology.

Reference intervals of mesenteric lymph node size according to lymphocyte counts in asymptomatic children

There is no acknowledged reference interval of mesenteric lymph node size in healthy children, and the size criterion for mesenteric lymph node enlargement (MLNE) has long been controversial. This study aimed to explore the reference intervals of mesenteric lymph node size according to lymphocyte counts in asymptomatic children and to develop a more appropriate definition of MLNE. The asymptomatic children included were divided into five age strata: 2 to 3 yr; 3 to 4 yr; 4 to 5 yr; 5 to 6 yr; and 6 to 7 yr. Correlation analyses between lymphocyte counts and the long-axis diameter, short-axis diameter, and average diameter of the largest mesenteric lymph node (LMLN) were performed. A reference interval of the short-axis diameter of LMLN was established according to this correlation analysis in each age group. We also report a reference interval of lymphocyte count in each age group. This study revealed significant correlations between the short-axis diameter of LMLN and lymphocyte count in all age groups, as well as in subdivided boy groups and girl groups. The overall reference interval of the short-axis diameter of LMLN in children was 0.54 cm—1.03 cm, with mean value of 0.75 cm. This study supports the use of the short-axis diameter greater than 8–10 mm as the diagnostic criterion for primary mesenteric lymphadenitis based on the presence of a cluster of three or more mesenteric lymph nodes and in the absence of other abnormalities.

Diagnostic Utility of Ultrasonography for Duodenal Ulcers in Pediatric Cases in Japan

Objective: To evaluate the diagnostic utility of wall hypertrophy of the duodenal bulb with a hyperechoic lumen, designated as the "HH sign," using ultrasound sonography (US) in pediatric duodenal ulcer (DU) patients. Study design: We performed a US for five pediatric subjects diagnosed with DU by upper gastroscopy to determine the presence of the potentially diagnostic HH sign. The sonographic images were analyzed before and after DU treatment. Computed tomography was performed in three cases and fecal occult blood test (FOBT) in all five cases. Results: Upper gastroscopy confirmed DU in all patients. While the HH sign was observed using US in four cases, with the DU located in the anterior bulb, the FOBT was positive in only one case. In these four cases, the HH sign diminished in response to treatment, as visualized by US. This was observed for both the initial as well as recurrent episodes. A mass-like region was observed in only one case, with the ulcer located in the proximity of the inferior duodenal wall. Conclusion: The HH sign is useful for the follow-up of DU, and US may be a suitable modality for the follow-up. We believe that this diagnostic marker can aid in following up a greater number of DU cases.

Standing CT of the equine head: Reducing radiation dose maintains image quality

Multiple published studies involving computed tomographic (CT) examinations of the equine head utilise a wide range of mAs parameters for image acquisition. This prospective, experimental study assessed the effects of lowering mAs during CT image acquisition on image quality and scatter radiation on 10 cadaver equine heads. Each head was scanned three times at 300, 225, and 150 mAs, with all other scanning parameters remaining constant between series. An anthropomorphic phantom was positioned adjacent to each equine head during image acquisition, mimicking a human bystander, with an ionization chamber attached to the phantom at eye level. Each series was reconstructed using filtered back projection, using medium (H30) and high (H80) frequency reconstruction algorithms. Quantitative image quality assessment was performed by calculating signal to noise ratio (SNR) and contrast to noise ratio (CNR). Two qualitative image quality assessments were performed independently by three blinded board certified veterinary radiologists with a 4 week interval, using a visual grade analysis model adapted from peer reviewed medical literature. Ionization chamber measurements, calculated volume CT dose index (CTDIvol), and dose-length product (DLP) were recorded. Halving radiation dose during image acquisition from 300 to 150mAs resulted in comparable image quality between series. There was a statistically significant and linear relationship between mAs and scatter radiation to the bystander; halving mAs during image acquisition resulted in halving of scatter radiation. Results of this cadaveric study support the use of lower mAs settings during standing CT examinations of the equine head.

Giant retroperitoneal liposarcoma: A case report and literature review

Retroperitoneal liposarcomas are a heterogeneous group of mesenchymal tumours that have a wide spectrum of histological subtypes and vague clinical presentations. Herein, we present the case of a 75-year-old man with anorexia, weight loss of 7 kg, and a growing abdominal circumference within a span of 6 weeks. Computed tomography of the abdomen and pelvis showed a large mass that filled almost the entire abdominal cavity. After consultation with a multidisciplinary tumour board, en bloc resection of the tumour was performed. In addition, the left kidney and a part of the left diaphragm were removed. The tumour measured 35 × 29 × 20.5 cm and weighed 11.6 kg. The histological report confirmed low-grade dedifferentiated liposarcoma with scarce atypical adipocytes, lipoblasts containing spindle cell, pleomorphic, and chondroid components. The patient had uneventful recovery and remained stable during the follow-up period. We report this case to highlight the need for customized surgical oncological measures in the treatment of solid abdominal tumours due to locoregional invasion that usually necessitates en bloc resection.

Comparative Volume Analysis of Alveolar Defects by 3D Simulation

A precise volumetric assessment of maxillary alveolar defects in patients with cleft lip and palate can reduce donor site morbidity or allow accurate preparation of bone substitutes in future applications. However, there is a lack of agreement regarding the optimal volumetric technique to adopt. This study measured the alveolar bone defects by using two cone-beam computed tomography (CBCT)-based surgical simulation methods. Presurgical CBCT scans from 32 patients with unilateral or bilateral clefts undergoing alveolar bone graft surgery were analyzed. Two hands-on CBCT-based volumetric measurement methods were compared: the 3D real-scale printed model-based surgical method and the virtual surgical method. Different densities of CBCT were compared. Intra- and inter-examiner reliability was assessed. For patients with unilateral clefts, the average alveolar defect volumes were 1.09 ± 0.24 and 1.09 ± 0.25 mL (p > 0.05) for 3D printing- and virtual-based models, respectively; for patients with bilateral clefts, they were 2.05 ± 0.22 and 2.02 ± 0.27 mL (p > 0.05), respectively. Bland–Altman analysis revealed that the methods were equivalent for unilateral and bilateral alveolar cleft defect assessment. No significant differences or linear relationships were observed between adjacent different densities of CBCT for model production to obtain the measured volumes. Intra- and inter-examiner reliability was moderate to good (intraclass correlation coefficient (ICC) > 0.6) for all measurements. This study revealed that the volume of unilateral and bilateral alveolar cleft defects can be equally quantified by 3D-printed and virtual surgical simulation methods and provides alveolar defect-specific volumes which can serve as a reference for planning and execution of alveolar bone graft surgery.

ORGAN DOSE ESTIMATION ACCOUNTING FOR UNCERTAINTY FOR PEDIATRIC AND YOUNG ADULT CT SCANS IN THE UNITED KINGDOM

Since our previous publication of organ dose for the pediatric CT cohort in the UK, there have been questions about the magnitude of uncertainty in our dose estimates. We therefore quantified shared and unshared uncertainties in empirical CT parameters extracted from 1073 CT films (1978-2008) from 36 hospitals in the study and propagated these uncertainties into organ doses using Monte Carlo random sampling and NCICT organ dose calculator. The average of 500 median brain and marrow doses for the full cohort was 35 (95% confidence interval: 30-40) mGy and 6 (5-7) mGy, respectively. We estimated that shared uncertainty contributed ~99% of coefficient of variation of median brain doses in brain scans compared to unshared uncertainty (1% contribution). We found that the previous brain doses were slightly underestimated for <1990 and overestimated for >1990 compared to the results in the current study due to the revised CTDI models based on CT films.

Accurate detection of renal leukemic involvement in children using 3-D computed tomography modeling

BACKGROUND

The rate of renal involvement in pediatric acute lymphoblastic leukemia (ALL) at diagnosis varies between reports because renal involvement is diagnosed on renal size larger than aged-matched standards on conventional modalities. We propose a new method for precise renal involvement detection using 3-D enhanced computed tomography (CT) reconstruction.

METHODS

Twenty-five children with ALL were evaluated utilizing 3-D enhanced CT reconstruction to measure renal volume before and after induction therapy, renal mass lesions and renal axis at diagnosis. Renal involvement was defined as a marked decrease of renal volume or the presence of mass lesions.

RESULTS

According to the 3D-CT criteria, nine of 25 patients (36%) had renal involvement. All of them had bilateral mass lesions except for one who had diffuse nephromegaly alone. This method detected renal involvement more accurately than ultrasonography. When using conventional criteria based on the length of the renal axis, 19 of 25 (76%) had renal involvement, including many cases of false-positive nephromegaly. Patients with renal involvement had significantly more extramedullary involvement according to the 3D-CT-based criteria.

CONCLUSIONS

The use of 3D-CT reconstruction was accurate in detecting renal involvement in childhood ALL, most of which consisted of piled up mass lesions. Patients with renal involvement should be worked up for the detection of other extramedullary lesions.

Longitudinal free-breathing MRI measurement of murine lung physiology in a progressive model of lung fibrosis

To longitudinally monitor progressive fibrosis in the transforming growth factor-α (TGF-α) transgenic mouse model of lung fibrosis, we used retrospective self-gating ultrashort echo time (UTE) magnetic resonance imaging (MRI) to image mouse lung at baseline and after 4 and 8 wk of fibrosis initiation via doxycycline administration. Only bitransgenic mice were used in this study and divided into two cohorts: six mice were fed doxycycline food to induce lung fibrosis (referred to as Dox cohort), and five other mice were fed normal food (referred to as control cohort). Lung mechanics, histology, and hydroxyproline were assessed after the final MRI. A linear mixed-effects model was used to analyze MRI-derived longitudinal lung-function parameters. Tidal volume decreased at a rate of -0.016 ± 0.002 ml/week [χ²(1) = 16.48, P < 0.001] for Dox cohort and increased at a rate of 0.010 ± 0.003 ml/week [χ²(1) = 6.37, P = 0.01] for control cohort. Minute ventilation decreased at a rate of -1.71 ± 0.26 ml·min^-1·wk^-1 [χ²(1) = 14.04, P < 0.001] for Dox cohort but did not change significantly over time for control cohort. High-density lung volume percentage increased at a rate of 3.9 ± 0.7%/wk for Dox cohort [χ²(1) = 11.47, P < 0.001] but did not change significantly over time for control cohort. MRI-derived lung structure and function parameters were strongly correlated with pleural thickness, hydroxyproline content, lung compliance, airway resistance, and airway elastance. We conclude that self-gating UTE MRI could be used to longitudinally monitor lung fibrosis in the TGF-α transgenic mouse model. NEW & NOTEWORTHY Self-gating UTE MRI was used to monitor morphology and physiology in lung fibrosis in a transforming growth factor-α transgenic mouse model. Tidal volume was shown for the first time to correlate strongly with conventional metrics of fibrosis such as hydroxyproline and pleural thickness.

Fractured pediatric central venous catheters - Repair or replace?

INTRODUCTION

Central venous catheter (CVC) fracture is a common complication. The aim of this study is to examine risk factors resulting in CVC fracture and compare outcomes of children undergoing CVC repair versus replacement.

METHODS

A retrospective chart review was conducted from 2000 to 2016 for children with tunneled CVCs. Children with CVC fractures were compared to those without to identify risk factors resulting in fracture. Children with fractured CVCs were divided into repair or replacement treatment groups and outcomes compared. A logistic regression model determined independent predictors of CVC-associated bloodstream infections (CLABSI) after fracture.

RESULTS

In the 236 children with CVCs, the fracture rate was 29.2%. Fractured CVCs were more common with double lumen CVC (p = 0.040) and children whose indication was total parenteral nutrition (p = 0.003). Given children often underwent multiple repairs or replacements. 98 CVC repairs and 41 replacements were analyzed. CVC replacements had longer durability than repair (181.98 vs. 98.9 days, p = 0.038). There were no differences in CLABSI incidence for repair vs. replacement (OR 0.5 CI 0.05-4.97) after controlling for other factors.

CONCLUSIONS

CVC fracture is a frequent complication in children with tunneled CVCs. CVC repair has no increased incidence of CLABSI but eliminates the intraoperative and anesthetic risks of CVC replacement.

TYPE OF STUDY

Retrospective cohort study.

LEVEL OF EVIDENCE

Level III.

Persistent radiologic thoracic hypotransparency: A case report and review of the literature

A thymolipoma is a slow-growing, anterior mediastinal tumor, rare in childhood. The authors present a report of a 4-year-old girl with persistent right thoracic hypotransparency on the chest radiograph. Computed tomography and magnetic resonance imaging revealed an anterior, well-limited, mediastinal mass of heterogeneous density, with lipomatous and soft tissue density areas. The tumor was totally excised and the histopathologic findings revealed a thymolipoma. A year and a half after surgery, the child remains well. This report enhances the relevance of differential diagnosis in the presence of persistent radiologic thoracic hypotransparency.

The Utility of Head Computed Tomography in the Evaluation of Apparent Life-Threatening Event

OBJECTIVE

This study aimed to evaluate the diagnostic utility of empiric head computed tomography (CT) in apparent life threatening event (ALTE).

METHODS

This was a retrospective chart review of children younger than 12 months presenting to an urban pediatric hospital and its suburban satellite for an ALTE from October 2009 to December 2012. The ALTE cases were identified as having had a diagnosis of ALTE (International Classification of Diseases, 9th Revision 799.82) or as having had a constellation of studies performed consistent with our institutional protocol for ALTE evaluation. Exclusion criteria were known trauma and cases lacking an identifiable ALTE feature on review.

RESULTS

There were 631 cases identified, of which 617 met inclusion and exclusion criteria. Of those, 537 had a head CT performed. Five patients were identified with clinically important head CT findings: a case of congenital toxoplasmosis, a case of intraventricular hemorrhage, and 3 cases of nonaccidental trauma (NAT). One of the NAT patients had a bruise on his forehead; the other patients had no historical, physical examination, and other laboratory or radiologic findings to raise concern for significant finding on head CT. The rate of clinically significant findings and occult clinically significant findings was 5/537 (0.93%) (95% confidence interval, 0.30%-2.16%; number needed to treat = 108) and 4/537 (0.75%) (95% confidence interval, 0.20%-1.90%; number needed to treat = 135), respectively.

CONCLUSIONS

The rate of clinically important head CT findings in ALTE evaluation was relatively rare, at 0.93%. Given the severe consequences of missing these cases, these data establish a role for empiric head CT in the evaluation of ALTE.

Old Data-New Concepts: Integrating "Indirect Effects" Into Radiation Protection

PURPOSE

To address the following key question, what are the consequences of nontargeted and delayed effects for linear nonthreshold models of radiation risk? This paper considers low-dose "indirect" or nontargeted effects and how they might impact radiation protection, particularly at the level of the environment. Nontargeted effects refer to effects in cells, tissues, or organisms that were not targeted by irradiation and that did not receive direct energy deposition. They include genomic instability and lethal mutations in progeny of irradiated cells and bystander effects in neighboring cells, tissues, or organisms. Low-dose hypersensitivity and adaptive responses are sometimes included under the nontargeted effects umbrella, but these are not considered in this paper. Some concepts emerging in the nontargeted effects field that could be important include historic dose. This suggests that the initial exposure to radiation initiates the instability phenotype which is passed to progeny leading to a transgenerational radiation-response phenotype, which suggests that the system response rather than the individual response is critical in determining outcome.

CONCLUSION

Nontargeted effects need to be considered, and modeling, experimental, and epidemiological approaches could all be used to determine the impact of nontargeted effects on the currently used linear nonthreshold model in radiation protection.

The International Atomic Energy Agency action plan on radiation protection of patients and staff in interventional procedures: Achieving change in practice

INTRODUCTION

The International Atomic Energy Agency (IAEA) organized the 3rd international conference on radiation protection (RP) of patients in December 2017. This paper presents the conclusions on the interventional procedures (IP) session.

MATERIAL AND METHODS

The IAEA conference was conducted as a series of plenary sessions followed by various thematic sessions. "Radiation protection of patients and staff in interventional procedures" session keynote speakers presented information on: 1) Risk management of skin injuries, 2) Occupational radiation risks and 3) RP for paediatric patients. Then, a summary of the session-related papers was presented by a rapporteur, followed by an open question-and-answer discussion.

RESULTS

Sixty-seven percent (67%) of papers came from Europe. Forty-four percent (44%) were patient studies, 44% were occupational and 12% were combined studies. Occupational studies were mostly on eye lens dosimetry. The rest were on scattered radiation measurements and dose tracking. The majority of patient studies related to patient exposure with only one study on paediatric patients. Automatic patient dose reporting is considered as a first step for dose optimization. Despite efforts, paediatric IP radiation dose data are still scarce. The keynote speakers outlined recent achievements but also challenges in the field. Forecasting technology, task-specific targeted education from educators familiar with the clinical situation, more accurate estimation of lens doses and improved identification of high-risk professional groups are some of the areas they focused on.

CONCLUSIONS

Manufacturers play an important role in making patients safer. Low dose technologies are still expensive and manufacturers should make these affordable in less resourced countries. Automatic patient dose reporting and real-time skin dose map are important for dose optimization. Clinical audit and better QA processes together with more studies on the impact of lens opacities in clinical practice and on paediatric patients are needed.

The cost effectiveness and utility of a "quick MRI" for the evaluation of intra-abdominal abscess after acute appendicitis in the pediatric patient population

INTRODUCTION

Contrast-enhanced CT remains the first-line imaging for evaluating postoperative abscess (POA) after appendicitis. Given concerns of ionizing radiation use in children, we began utilizing quick MRI to evaluate POA and summarize our findings in this study.

MATERIALS AND METHODS

Children imaged with quick MRI from 2015 to 2017 were compared to children evaluated with CT from 2012 to 2014 using an age and weight matched case-control model. Radiation exposure, size and number of abscesses, length of exam, drain placement, and patient outcomes were compared.

RESULTS

There was no difference in age or weight (p>0.60) between children evaluated with quick MRI (n=16) and CT (n=16). Mean imaging time was longer (18.2±8.5min) for MRI (p<0.001), but there was no difference in time from imaging order to drain placement (p=0.969). No children required sedation or had non-diagnostic imaging. There were no differences in abscess volume (p=0.346) or drain placement (p=0.332). Thirty-day follow-up showed no difference in readmissions (p=0.551) and no missed abscesses. Quick MRI reduced imaging charges to $1871 from $5650 with CT.

CONCLUSION

Quick MRI demonstrated equivalent outcomes to CT in terms of POA detection, drain placement, and 30-day complications suggesting that MRI provides an equally effective, less expensive, and non-radiation modality for the identification of POA.

TYPE OF STUDY

Retrospective Case-Control Study.

LEVEL OF EVIDENCE

Level III.

Course of acute nonspecific mesenteric lymphadenitis: single-center experience

Available reports dealing with acute nonspecific mesenteric lymphadenitis do not address the total duration of symptoms. However, it is commonly assumed a time for recovery ≤ 4 weeks. The purpose of this report was to investigate the course of acute nonspecific mesenteric lymphadenitis in childhood. A review was made of the patients aged ≤ 16 years in whom the diagnosis of acute nonspecific mesenteric lymphadenitis was established between 2011 and 2015 at the Pediatric Emergency Unit. The records of the Pediatric Emergency Unit, those of the referring family doctors, and the results of a structured telephone interview with each family were used. Forty-four patients (25 girls and 19 boys) aged 2.5 to 16, median 8.2, years were included. A bimodal distribution in duration of symptoms was observed: symptoms persisted for ≤ 2 weeks in 22 patients and 3 to 10 weeks in 22. Clinical and laboratory characteristics were similar in children with symptoms persisting for 2 weeks or less 28 and in those with symptoms persisting for 3-10 weeks.

CONCLUSION

In patients affected with acute nonspecific mesenteric lymphadenitis, it is advantageous to think of the time span for recovery in terms of ≥ 4 weeks. What is Known: • Mesenteric adenitis is a self-limiting inflammatory condition with well-characterized clinical presentation and imaging features. • A total duration of symptoms of ≤ 4 weeks is usually hypothesized. What is New: • Symptoms persist for 3 to 10 weeks in half of the patients. • At presentation, clinical and laboratory characteristics are similar in children with symptoms persisting for 2 weeks or less and in those with 45 symptoms persisting for 3-10 weeks.

Computed tomography use in a large Italian region: trend analysis 2004-2014 of emergency and outpatient CT examinations in children and adults

OBJECTIVES

To analyse CT use in recent years in a high-density Italian area (±10 million inhabitants, including 1 million children), focusing on developing age.

METHODS

Retrospective analysis of records from HealthCare IT System, covering >400 hospitals and clinics. Description of CT use between 2004-2014 in emergency and outpatient care and assessment of radiation exposure trend.

RESULTS

Over 9 million scans were performed. Emergency procedures showed a global increase of 230 %, mainly head examinations. In the global outpatient setting, the annual number of CT scans/person increased ±19 %. A moderate increase in CT examinations was observed in the developing age population, while a remarkable increase in dental, chest and abdominal procedures occurred for the 10- to 30-year age range. The increase in mean annual dose/capita in the global patient pool was approximately 42 %, increasing from 0.72-1.03 mSv. The population rate receiving an annual CT radiation dose/capita higher than 1 mSv tripled in the 11-year interval, increasing from 16-48 %.

CONCLUSIONS

The remarkable increase in radiation exposure raises a special concern for teenagers and young adults, whose risk tends to be underestimated. The fivefold increase in dental CTs in the younger age groups requires further investigations.

KEY POINTS

• Literature highlights a remarkable increase in CT use over the last decades. • The paediatric age had higher exposure to X-ray risk. • A detailed retrospective analysis of more than 9 million scans was performed. • Dental, chest, abdominal procedures increased remarkably in 10- to 30-year age range. • This study raises concern about exposure for teenagers and young adults.

Toward a Framework for Benefit-Risk Assessment in Diagnostic Imaging: Identifying Scenario-specific Criteria

RATIONALE AND OBJECTIVES

Diagnostic imaging has many effects and there is no common definition of value in diagnostic radiology. As benefit-risk trade-offs are rarely made explicit, it is not clear which framework is used in clinical guideline development. We describe initial steps toward the creation of a benefit-risk framework for diagnostic radiology.

MATERIALS AND METHODS

We performed a literature search and an online survey of physicians to identify and collect benefit-risk criteria (BRC) relevant to diagnostic imaging tests. We operationalized a process for selection of BRC with the use of four clinical use case scenarios that vary by diagnostic alternatives and clinical indication. Respondent BRC selections were compared across clinical scenarios and between radiologists and nonradiologists.

RESULTS

Thirty-six BRC were identified and organized into three domains: (1) those that account for differences attributable only to the test or device (n = 17); (2) those that account for clinical management and provider experiences (n = 12); and (3) those that capture patient experience (n = 7). Forty-eight survey participants selected 22 criteria from the initial list in the survey (9-11 per case). Engaging ordering physicians increased the number of criteria selected in each of the four clinical scenarios presented. We developed a process for standardizing selection of BRC in guideline development.

CONCLUSION

These results suggest that a process relying on elements of comparative effectiveness and the use of standardized BRC may ensure consistent examination of differences among alternatives by way of making explicit implicit trade-offs that otherwise enter the decision-making space and detract from consistency and transparency. These findings also highlight the need for multidisciplinary teams that include input from ordering physicians.

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

Computed tomography (CT) is an essential tool in modern medicine and is frequently used to diagnose a wide range of conditions, particularly in industrial countries, such as Japan and Germany. However, markedly higher doses of ionizing radiation are delivered during CT imaging than during conventional X-ray examinations. To assess pediatric CT practice patterns, data from three university hospital databases (two in Japan and one in Germany) were analyzed. Anonymized data for patients aged 0 to 14 years who had undergone CT examinations between 2008 and 2010 were extracted. To assess CT practice, an interdisciplinary classification scheme for CT indications, which incorporated the most common examination types and radiosensitive tissues, was developed. The frequency of CT examinations was determined according to sex, age at examination, and indications. A total of 5182 CT examinations were performed in 2955 children. Overall, the frequency of CT examinations at the Japanese university hospitals did not differ significantly from that at the German hospital. However, differences were detected in the age distribution of the patients who underwent CT examinations (the proportion of patients <5 years of age was significantly higher in Japan than in Germany) and in the indications for CT. Substantial practice differences regarding the use of CT in pediatric health care were detected between the three hospitals. The results of this study point towards a need for approaches such as clinical guidelines to reduce unwarranted medical radiation exposures, particularly abdominal and head CT, in the Japanese health system.

Computed Tomography in Germany

BACKGROUND

In 2001, calculations in models based on atomic bomb survivors indicated that children exposed to ionizing radiation by computed tomography (CT) would be expected to have an increased risk of cancer. This led to the issuance of new recommendations in Germany concerning CT in children.

METHODS

We analyzed data from the German pediatric CT cohort study together with data on children from a large general statutory health insurance provider (AOK) in order to characterize the secular trend in the use of CT in Germany. We used information from the Picture Archiving and Communication System (PACS) to estimate individual organ doses per scan and their development over time.

RESULTS

The number of CT scans performed on children in Germany each year declined by 29% from 2006 to 2012. Over the same period, younger children were exposed to lower organ doses during CT scanning, although some organ doses were higher in neonates than in older children. The highest organ doses were in the 7.6 to 12.5-year-old age group and affected the brain (37.12 mGy ± 19.68 mGy) and the lenses (41.24 mGy ± 20.08 mGy). In every age group, the organ doses declined from year to year. With approximately 21 000 children aged 0-13 undergoing CT each year (extrapolated from insurance data of 2008), one can expect 2.3 [-1.7; 6.3] additional new cases of leukemia and 1 [-2.3; 4.0] additional new tumor of the central nervous system to arise each year.

CONCLUSION

In view of the risks, children should undergo CT only for the indications listed by the German Commission on Radiological Protection (Strahlenschutzkommission). Further epidemiological studies are needed for estimation of the risk associated with the use of newer CT technology.

Use of Anesthesia for Imaging Studies and Interventional Procedures in Children

Ongoing investigation from the Pediatric Anesthesia NeuroDevelopment Assessment (PANDA) study hopes to examine the long-term effect on cognitive and language development of a single anesthetic exposure in children undergoing inguinal hernia repair. The fifth PANDA Symposium, held in April 2016, continued the mission of previous symposia to examine evidence from basic science and clinical studies on potential neurotoxic effects of anesthetics on developing brain. At the 2016 Symposium, a panel of specialists from nonsurgical pediatric disciplines including anesthesiology, radiology, neurology, gastroenterology, oncology, cardiology, and critical care reviewed use of anesthesia in their practices, including how concern over possible neurodevelopmental effects of early childhood anesthetic exposure has changed discussion with patients and families regarding risks and benefits of imaging studies and interventional procedures involving sedation or anesthesia. This paper summarizes presentations from nonsurgical pediatric specialists at the 2016 PANDA Symposium.

Pediatric/"Wildtype" gastrointestinal stromal tumors

Pediatric/"Wildtype" gastrointestinal stromal tumor (P/WT-GIST) is a rare cancer, distinct and markedly different from the phenotype found predominantly in older patients (adult, non-wildtype GIST). Having a different molecular signature, it is not responsive to standard adjuvant therapies utilized in adult GIST, and surgery remains the only effective cure. However, even with presumed complete resections in patients with localized disease at presentation, recurrence rates are high. Furthermore, it is an indolent cancer that can persist for decades, and treatment strategies must balance the possible morbid risks of intervention with the reality of preserving quality of life in the interim. Effective adjuvant therapies remain elusive, and research is critically needed to identify both targets and drugs for treatment consideration.

Software-based PET-MR image coregistration: combined PET-MRI for the rest of us!

BACKGROUND

With the introduction of hybrid positron emission tomography/magnetic resonance imaging (PET/MRI), a new imaging option to acquire multimodality images with complementary anatomical and functional information has become available. Compared with hybrid PET/computed tomography (CT), hybrid PET/MRI is capable of providing superior anatomical detail while removing the radiation exposure associated with CT. The early adoption of hybrid PET/MRI, however, has been limited.

OBJECTIVE

To provide a viable alternative to the hybrid PET/MRI hardware by validating a software-based solution for PET-MR image coregistration.

MATERIALS AND METHODS

A fully automated, graphics processing unit-accelerated 3-D deformable image registration technique was used to align PET (acquired as PET/CT) and MR image pairs of 17 patients (age range: 10 months-21 years, mean: 10 years) who underwent PET/CT and body MRI (chest, abdomen or pelvis), which were performed within a 28-day (mean: 10.5 days) interval. MRI data for most of these cases included single-station post-contrast axial T1-weighted images. Following registration, maximum standardized uptake value (SUVmax) values observed in coregistered PET (cPET) and the original PET were compared for 82 volumes of interest. In addition, we calculated the target registration error as a measure of the quality of image coregistration, and evaluated the algorithm's performance in the context of interexpert variability.

RESULTS

The coregistration execution time averaged 97±45 s. The overall relative SUVmax difference was 7% between cPET-MRI and PET/CT. The average target registration error was 10.7±6.6 mm, which compared favorably with the typical voxel size (diagonal distance) of 8.0 mm (typical resolution: 0.66 mm × 0.66 mm × 8 mm) for MRI and 6.1 mm (typical resolution: 3.65 mm × 3.65 mm × 3.27 mm) for PET. The variability in landmark identification did not show statistically significant differences between the algorithm and a typical expert.

CONCLUSION

We have presented a software-based solution that achieves the many benefits of hybrid PET/MRI scanners without actually needing one. The method proved to be accurate and potentially clinically useful.

Non-invasive intracranial pressure assessment

Assessing intracranial pressure (ICP) remains a cornerstone in neurosurgical care. Invasive techniques for monitoring ICP remain the gold standard. The need for a reliable, safe and reproducible technique to non-invasively assess ICP in the context of early screening and in the neurocritical care environment is obvious. Numerous techniques have been described with several novel advances. While none of the currently available techniques appear independently accurate enough to quantify raised ICP, there is some promising work being undertaken.

CT radiation dose awareness among paediatricians

BACKGROUND

The radiation dose delivered from computed tomography (CT) scanning and the risks associated with ionising radiation are major concerns in paediatric imaging. Compared to adults, children have increased organ sensitivity and a longer expected lifetime in which cancer may develop. Therefore, it is important to investigate the awareness of paediatricians (referring physicians) regarding radiation doses and the associated risks.

METHODS

A multiple-choice survey was distributed among paediatricians in 8 hospitals in Riyadh, the capital of Saudi Arabia.

RESULTS

Among the 162 respondents, only 24 (15 %) were aware of the As Low As Reasonably Achievable (ALARA) principle. Approximately half (54 %) of the respondents believed that multi-slice CT delivered a low radiation dose, and 100 (62 %) of the respondents were not aware that radiation is considered carcinogenic by the Food and Drug Administration in the United States. Among the respondents, 110 (68 %) did not have any specific education regarding radiation during their training. There was an overall underestimation (83 %) of the CT radiation dose, and 70 % thought that magnetic resonance imaging (MRI) delivered some level of ionising radiation.

CONCLUSIONS

Among paediatricians in Saudi Arabian hospitals, there was a wide underestimation of the CT radiation dose and the associated risks for children. We should improve paediatricians' knowledge about radiation doses. Radiologists, paediatricians, radiation technologists and medical physicists should work together to optimise CT guidelines and protocols to reduce the radiation risks for children.

Optimised paediatric CT dose at a tertiary children's hospital in Japan: a 4-y single-centre analysis

Since diagnostic reference levels (DRLs) for children are not currently established in Japan, the authors determined local DRLs for the full range of paediatric CT examinations in a single tertiary care children's hospital. A retrospective review of 4801 CT performance records for paediatric patients (<15 y old) who had undergone CT examinations from 2008 to 2011 was conducted. The most frequent examinations were of the head (52 %), followed by cardiac (15 %), temporal bone (9 %), abdomen (7 %), chest (6 %) and others (11 %). Approximately one-third of children received two or more CT scans. The authors' investigation showed that mean CTDIvol and DLP for head, chest and abdomen increased as a function of age. Benchmarking of the results showed that CTDIvol, DLP and effective dose for chest and abdomen examinations in this hospital were below average, whereas those for the head tended to be at or slightly above average of established DRL values from five countries. The results suggest that CT examinations as performed in a tertiary children's hospital in Japan are well optimised.

Three-dimensional analysis of cranial and facial asymmetry after helmet therapy for positional plagiocephaly

PURPOSE

Helmet therapy is a non-surgical option for treating positional plagiocephaly, and its effectiveness has been validated by various researches. In addition to cranial flattening and asymmetry, ipsilateral prominence of the mid-face and relative anterior transposition of the ipsilateral ear is also common. Hence, we investigated the impact of helmet therapy on mid-facial asymmetry.

METHODS

Ninety-nine patients diagnosed with positional plagiocephaly and treated by helmet therapy between September 2005 and July 2012 were enrolled. Therapy was initiated at various ages: group I, <6 months (n = 35); group II, 6 months to 1 year (n = 43); group III, >1 year (n = 21). A cranial vault asymmetry index was measured at the levels of the inferior orbital rim (CVAIIOR-MF) and superior orbital rim (CVAISOR-LC) and midway from the superior orbital rim to the vertex (CVAIMID-UC). Anterior transposition of the ipsilateral ear was verified by measuring the distance (D EAR) between the actual position of the ear and its expected position relative to the contralateral ear. All variables were compared before and after helmet therapy and were categorized by age at treatment initiation.

RESULTS

CVAIIOR-MF and CVAISOR-LC were lower in all three age groups after helmet therapy, confirming therapeutic efficacy. CVAIMID-UC (upper level cranial asymmetry) and D EAR (mid-facial soft tissue asymmetry) also improved significantly in groups I and II which were younger than 1 year old.

CONCLUSION

In positional plagiocephaly, helmet therapy is effective in correcting both cranial and mid-facial asymmetries. Outcomes were optimal in patients <1 year of age, but older patients also showed some improvement.

Risk of cancer incidence before the age of 15 years after exposure to ionising radiation from computed tomography: results from a German cohort study

The aim of this cohort study was to assess the risk of developing cancer, specifically leukaemia, tumours of the central nervous system and lymphoma, before the age of 15 years in children previously exposed to computed tomography (CT) in Germany. Data for children with at least one CT between 1980 and 2010 were abstracted from 20 hospitals. Cancer cases occurring between 1980 and 2010 were identified by stochastic linkage with the German Childhood Cancer Registry (GCCR). For all cases and a sample of non-cases, radiology reports were reviewed to assess the underlying medical conditions at time of the CT. Cases were only included if diagnosis occurred at least 2 years after the first CT and no signs of cancer were recorded in the radiology reports. Standardised incidence ratios (SIR) using incidence rates from the general population were estimated. The cohort included information on 71,073 CT examinations in 44,584 children contributing 161,407 person-years at risk with 46 cases initially identified through linkage with the GCCR. Seven cases had to be excluded due to signs possibly suggestive of cancer at the time of first CT. Overall, more cancer cases were observed (O) than expected (E), but this was mainly driven by unexpected and possibly biased results for lymphomas. For leukaemia, the SIR (SIR = O/E) was 1.72 (95 % CI 0.89-3.01, O = 12), and for CNS tumours, the SIR was 1.35 (95 % CI 0.54-2.78, O = 7). Despite careful examination of the medical information, confounding by indication or reverse causation cannot be ruled out completely and may explain parts of the excess. Furthermore, the CT exposure may have been underestimated as only data from the participating clinics were available. This should be taken into account when interpreting risk estimates.

Estimated risk of radiation-induced cancer from paediatric chest CT: two-year cohort study

BACKGROUND

The increasing absolute number of paediatric CT scans raises concern about the safety and efficacy and the effects of consecutive diagnostic ionising radiation.

OBJECTIVE

To demonstrate a method to evaluate the lifetime attributable risk of cancer incidence/mortality due to a single low-dose helical chest CT in a two-year patient cohort.

MATERIALS AND METHODS

A two-year cohort of 522 paediatric helical chest CT scans acquired using a dedicated low-dose protocol were analysed retrospectively. Patient-specific estimations of radiation doses were modelled using three different mathematical phantoms. Per-organ attributable cancer risk was then estimated using epidemiological models. Additional comparison was provided for naturally occurring risks.

RESULTS

Total lifetime attributable risk of cancer incidence remains low for all age and sex categories, being highest in female neonates (0.34%). Summation of all cancer sites analysed raised the relative lifetime attributable risk of organ cancer incidence up to 3.6% in female neonates and 2.1% in male neonates.

CONCLUSION

Using dedicated scan protocols, total lifetime attributable risk of cancer incidence and mortality for chest CT is estimated low for paediatric chest CT, being highest for female neonates.

Retroperitoneal liposarcoma: current insights in diagnosis and treatment

Retroperitoneal liposarcoma (RLS) is a rare, biologically heterogeneous tumor that present considerable challenges due to its size and deep location. As a consequence, the majority of patients with high-grade RLS will develop locally recurrent disease following surgery, and this constitutes the cause of death in most patients. Here, we review current insights and controversies regarding histology, molecular biology, extent of surgery, (neo)adjuvant treatment, and systemic treatment including novel targeted agents in RLS.

Are the studies on cancer risk from CT scans biased by indication? Elements of answer from a large-scale cohort study in France

BACKGROUND

Recent epidemiological results suggested an increase of cancer risk after receiving computed tomography (CT) scans in childhood or adolescence. Their interpretation is questioned due to the lack of information about the reasons for examination. Our objective was to estimate the cancer risk related to childhood CT scans, and examine how cancer-predisposing factors (PFs) affect assessment of the radiation-related risk.

METHODS

The cohort included 67,274 children who had a first scan before the age of 10 years from 2000 to 2010 in 23 French departments. Cumulative X-rays doses were estimated from radiology protocols. Cancer incidence was retrieved through the national registry of childhood cancers; PF from discharge diagnoses.

RESULTS

During a mean follow-up of 4 years, 27 cases of tumours of the central nervous system, 25 of leukaemia and 21 of lymphoma were diagnosed; 32% of them among children with PF. Specific patterns of CT exposures were observed according to PFs. Adjustment for PF reduced the excess risk estimates related to cumulative doses from CT scans. No significant excess risk was observed in relation to CT exposures.

CONCLUSIONS

This study suggests that the indication for examinations, whether suspected cancer or PF management, should be considered to avoid overestimation of the cancer risks associated with CT scans.

Risk of malignancy associated with head and neck CT in children: a systematic review

OBJECTIVE

To perform a systematic review to evaluate the risk of malignancy associated with computed tomography (CT) of the head and/or neck in infants, children, and adolescents.

DATA SOURCES

Pubmed, EMBASE, and the Cochrane Library were assessed from the date of their inception to January 2014. Additionally, manual searches of bibliographies were performed and topic experts were contacted.

REVIEW METHODS

Data were obtained from studies measuring or estimating the risks of malignancy associated with radiation from head and/or neck CT in pediatric populations according to an a priori protocol. Two independent evaluators corroborated the extracted data.

RESULTS

There were 16 criterion-meeting studies that included data from n = 858,815 patients. The radiation-related risk of malignancy was estimated using primary patient data for both the exposure and outcome in a minority of studies, with most analyses utilizing mathematical modeling techniques. The data regarding otolaryngology-specific studies were limited and suggested a borderline significant increase in the risk of all combined cancers after facial CT (incidence rate ratio [IRR] = 1.14; 95% CI, 1.01-1.28) and neck/spine CT (IRR = 1.13; 95% CI, 1.00-1.28). Cohort data suggest that 1 excess brain malignancy occurred after 4000 brain CTs (40 mSv per scan) and that the estimated risk in the 10 years following CT exposure was 1 brain tumor per 10,000 patients exposed to a 10 mGy scan at less than 10 years of age.

CONCLUSION

Detailed understanding of any potential malignancy risk associated with pediatric imaging of the head and neck furthers our ability to engage in rational, shared, informed decision making with families considering CT scan.

Imaging of the small bowel: Crohn’s disease in paediatric patients

In more than 20% of all patients, the Crohn’s disease presents before the age of 18years. The diagnosis and management of Crohn’s disease in children has changed dramatically over the last decade, mainly due to increased awareness, availability of newer diagnostic modalities such as magnetic resonance imaging (MRI) and newer, more powerful treatments such as biologics. Imaging of the small bowel is needed for diagnosis, management, follow-up and also evaluation of the disease in terms of location, extent, activity and complications. We review all the methods (barium examinations, ultrasonography, computed tomography, MR, and computed tomography- positron emission tomography) commonly used for imaging the small bowel in paediatric patients with Crohn’s disease analyzing the advantages and disadvantages of each modality, with particular emphasis on MR imaging.

Imaging mouse lung allograft rejection with (1)H MRI

PURPOSE

To demonstrate that longitudinal, noninvasive monitoring via MRI can characterize acute cellular rejection in mouse orthotopic lung allografts.

METHODS

Nineteen Balb/c donor to C57BL/6 recipient orthotopic left lung transplants were performed, further divided into control-Ig versus anti-CD4/anti-CD8 treated groups. A two-dimensional multislice gradient-echo pulse sequence synchronized with ventilation was used on a small-animal MR scanner to acquire proton images of lung at postoperative days 3, 7, and 14, just before sacrifice. Lung volume and parenchymal signal were measured, and lung compliance was calculated as volume change per pressure difference between high and low pressures.

RESULTS

Normalized parenchymal signal in the control-Ig allograft increased over time, with statistical significance between day 14 and day 3 posttransplantation (0.046→0.789; P < 0.05), despite large intermouse variations; this was consistent with histopathologic evidence of rejection. Compliance of the control-Ig allograft decreased significantly over time (0.013→0.003; P < 0.05), but remained constant in mice treated with anti-CD4/anti-CD8 antibodies.

CONCLUSION

Lung allograft rejection in individual mice can be monitored by lung parenchymal signal changes and by lung compliance through MRI. Longitudinal imaging can help us better understand the time course of individual lung allograft rejection and response to treatment.

Radiation reduction in pediatric and adult congenital patients during cardiac catheterization

OBJECTIVES

Our objective was to determine if technical changes combined with radiation safety initiatives reduced the radiation dose delivered to patients during congenital catheterization.

BACKGROUND

Use of ionizing radiation is necessary during cardiac catheterization. Minimizing radiation dose, while maintaining clinically useful image quality, is an important safety issue. In our congenital heart center intentional practice changes, including technical changes and provider awareness initiatives, were implemented to decrease radiation dose.

METHODS

Data were retrospectively collected for all procedures involving children and adults with congenital heart disease (CHD) undergoing catheterization over 45 months. Cases were divided into three categories including: noninterventional (NI), simple intervention (SI), and complex intervention (CI). The change in dose was modeled as log of cumulative air kerma (Ka,r ). The change in Ka,r was evaluated for each procedural category as well as changes occurring as a function of age and weight.

RESULTS

Considering all procedures (n = 1,082), Ka,r decreased by 61%. In the NI group (n = 481), Ka,r decreased by 71%. In the SI group (n = 424), Ka,r decreased by 74%. The Ka,r for the 10-17 year old group (n = 125) and those ≥18 years (n = 709) decreased 74 and 67%, respectively. The Ka,r decreased 72 and 66% for those 20-60 kg and ≥60 kg, respectively. Groups not showing significant change in Ka,r included CI, age ≤9 years, and weight ≤20 kg.

CONCLUSIONS

Through technical changes and provider awareness initiatives, our institution dramatically reduced the radiation dose in the majority of pediatric and adult CHD patients undergoing cardiac catheterization.