Computed tomography and radiation risks: what pediatric health care providers should know

Evidence-based assessment of severe pediatric traumatic brain injury and emergent neurocritical care

Pediatric traumatic brain injury accounts for approximately 474,000 emergency department visits, 37,000 hospitalizations, and 3,000 deaths in children 14 years and younger annually in the United States. Acute neurocritical care in children has advanced with specialized pediatric trauma centers and emergency medical services. This article reviews pediatric-specific diagnosis, management, and medical decision making related to the neurocritical care of severe traumatic brain injury.

Lower radiation exposure from body CT imaging for trauma at a dedicated pediatric hospital

PURPOSE

We compare radiation exposure from body CT imaging for blunt trauma performed at outside hospitals (OH) versus our children's hospital (CH).

METHODS

We performed a retrospective chart review of all children transferred to our facility for management of trauma after undergoing a body CT scan at an OH from June 2011 to August 2013. Radiation from OH images was compared to our CH by matching to age, gender, and nearest date. Radiation measures included dose length product (DLP), computed tomography dose index (CTDI), and size-specific dose estimate (SSDE).

RESULTS

Fifty-one children were transferred from 39 OH. Abdomen/pelvis and chest/abdomen/pelvis imaging was performed in 30 and 21 children, respectively. Demographics are shown in Table 1. Results are illustrated in Tables 2 and 3. Contrast was utilized in 45 (1 oral, 41 IV, 3 both) and 51 (49 IV, 2 both). CT scans were performed at OH and CH, respectively (P=0.03).

CONCLUSIONS

Children receive significantly less radiation exposure with body CT imaging for blunt trauma when performed at our dedicated CH. CT scans were significantly more likely to be ordered with appropriate contrast at our CH.

Variation in the documentation of findings in pediatric voiding cystourethrogram

BACKGROUND

Few standards exist for reporting results of voiding cystourethrogram (VCUG).

OBJECTIVE

To assess the variation in reporting of VCUG findings from different facilities using a standardized assessment tool.

MATERIALS AND METHODS

VCUG reports were evaluated for demographic, technical, anatomical and functional information. Reports were categorized by age, gender, indication and vesicouretal reflux (VUR) status. Institutions were classified as a free-standing pediatric hospital (n = 3), pediatric hospital within a hospital (n = 11), or non-pediatric facility (n = 24) and reports were classified as having been read by a pediatric radiologist or not. Each category of outside reports (n = 152) was randomly matched with a twice-larger group of Hospital A reports from the same category (n = 304). Multivariate linear regression was used to analyze the association between the primary outcome (percentage of items described in dictated VCUG report) and the type of radiologist and institution.

RESULTS

Of the 456 studies, 66% were in girls, 56% were in those <12 months old, and the indication was urinary tract infection (UTI) in 81%. The mean percentage of items reported was 67 ± 14% (74 ± 7% at free-standing pediatric hospitals, 61 ± 10% at pediatric hospitals within a hospital, and 48 ± 11% at non-pediatric facilities). In multivariate analysis, VCUG reports generated at non-pediatric facilities had 17% fewer items included (95% CI: 14.5-19.7%, P < 0.0001), and pediatric hospitals within a hospital had 9% fewer items included (5.9-12.5%, P < 0.0001) when compared to free-standing pediatric hospitals. Reports read by a pediatric radiologist had 12% more items included (9.1-15.3%, P < 0.0001) compared to those read by a non-pediatric radiologist.

CONCLUSION

More complete VCUG reports were observed when generated at free-standing pediatric hospitals and when interpreted by a pediatric radiologist.

Reducing the number of rigid bronchoscopies performed in suspected foreign body aspiration cases via the use of chest computed tomography: is it safe? A literature review

BACKGROUND

Foreign body aspiration is common and potentially life threatening. Although rigid bronchoscopy has the potential for serious complications, it is the 'gold standard' of diagnosis. It is used frequently in light of the inaccuracy of clinical examination and chest radiography. Computed tomography is proposed as a non-invasive alternative to rigid bronchoscopy.

OBJECTIVE

This study aimed to evaluate the accuracy and safety of computed tomography used in the diagnosis of suspected foreign body aspiration, and compare this with the current gold standard, in order to examine the possibility of using computed tomography to reduce the number of diagnostic rigid bronchoscopies performed.

METHOD

The study comprised a review of literature published from 1970 to 2013, using the PubMed, Scopus, Web of Knowledge, Embase and Medline electronic databases.

RESULTS

The sensitivity for computed tomography ranged between 90 and 100 per cent, with four studies demonstrating 100 per cent sensitivity. Specificity was between 75 and 100 per cent. Radiation exposure doses averaged 2.16 mSv.

CONCLUSION

Computed tomography is a sensitive and specific modality in the diagnosis of foreign body aspiration, and its future use will reduce the number of unnecessary rigid bronchoscopies.

A novel weighted total difference based image reconstruction algorithm for few-view computed tomography

In practical applications of computed tomography (CT) imaging, due to the risk of high radiation dose imposed on the patients, it is desired that high quality CT images can be accurately reconstructed from limited projection data. While with limited projections, the images reconstructed often suffer severe artifacts and the edges of the objects are blurred. In recent years, the compressed sensing based reconstruction algorithm has attracted major attention for CT reconstruction from a limited number of projections. In this paper, to eliminate the streak artifacts and preserve the edge structure information of the object, we present a novel iterative reconstruction algorithm based on weighted total difference (WTD) minimization, and demonstrate the superior performance of this algorithm. The WTD measure enforces both the sparsity and the directional continuity in the gradient domain, while the conventional total difference (TD) measure simply enforces the gradient sparsity horizontally and vertically. To solve our WTD-based few-view CT reconstruction model, we use the soft-threshold filtering approach. Numerical experiments are performed to validate the efficiency and the feasibility of our algorithm. For a typical slice of FORBILD head phantom, using 40 projections in the experiments, our algorithm outperforms the TD-based algorithm with more than 60% gains in terms of the root-mean-square error (RMSE), normalized root mean square distance (NRMSD) and normalized mean absolute distance (NMAD) measures and with more than 10% gains in terms of the peak signal-to-noise ratio (PSNR) measure. While for the experiments of noisy projections, our algorithm outperforms the TD-based algorithm with more than 15% gains in terms of the RMSE, NRMSD and NMAD measures and with more than 4% gains in terms of the PSNR measure. The experimental results indicate that our algorithm achieves better performance in terms of suppressing streak artifacts and preserving the edge structure information of the object.

Congenital lung malformations: informing best practice

The management of congenital lung malformations is controversial both in the prenatal and postnatal periods. This article attempts to inform best practice by reviewing the level of evidence with regard to prenatal diagnosis, prognosis, and management and postnatal management, including imaging, surgical indication, surgical approach, and risk of malignancy. We present a series of clinically relevant statements along those topics and analyze the evidence for each. In the end, we make a plea for an adequate description of the lesions, both before and after birth, which will allow future comparisons between management options and the initiation of prospective registries.

Dose indices: everybody wants a number

This paper discusses the merits and weaknesses of the standard terms that have been developed to quantify CT dose: CT dose indices (CTDI), dose length product (DLP) and effective dose. The difference between the measured CTDIvol and the CTDIvol displayed on the CT scanner illustrates a clinical dilemma. Displayed CTDIvol represents the radiation dose delivered to a plastic phantom, which is significantly different from the dose delivered to the patient, depending on the size of the patient. Although effective dose is simple to calculate for an individual patient, it was never intended for this purpose. The need for a simple, appropriate method to estimate pediatric patient doses led to the development of the size-specific dose estimate (SSDE), the newest CT dose index. Here I compare SSDE and its merits to the use of effective dose to estimate patient dose. The discussion concludes with a few sample calculations and basic clinical applications of SSDE to better quantify pediatric patient dose from CT scans.

Advanced neuroimaging of mild traumatic brain injury

This article focuses on advancements in neuroimaging techniques, compares the advantages of each of the modalities in the evaluation of mild traumatic brain injury, and discusses their contribution to our understanding of the pathophysiology as it relates to prognosis. Advanced neuroimaging techniques discussed include anatomic/structural imaging techniques, such as diffusion tensor imaging and susceptibility-weighted imaging, and functional imaging techniques, such as functional magnetic resonance imaging, perfusion-weighted imaging, magnetic resonance spectroscopy, and positron emission tomography.

What all physicians should know about the potential radiation risk that computed tomography poses for paediatric patients

The repeated use of CT imaging raises a child's radiation exposure, overall radiation accrual and future cancer risks. However, our review suggests that these risks can be considerably reduced by physicians, radiologists and academic bodies, through proper justification, optimisation and dose limitation.

CONCLUSION

Computed tomography poses a potential risk of radiation-induced cancer in children. The physician must weigh up the overall risks and benefits of CT before referring a child for imaging.

Optimizing the balance between radiation dose and image quality in pediatric head CT: findings before and after intensive radiologic staff training

OBJECTIVE

The purpose of this study was to assess the radiation dose and image quality of pediatric head CT examinations before and after radiologic staff training.

MATERIALS AND METHODS

Outpatients 1 month to 14 years old underwent 215 unenhanced head CT examinations before and after intensive training of staff radiologists and technologists in optimization of CT technique. Patients were divided into three age groups (0-4, 5-9, and 10-14 years), and CT dose index, dose-length product, tube voltage, and tube current-rotation time product values before and after training were retrieved from the hospital PACS. Gray matter conspicuity and contrast-to-noise ratio before and after training were calculated, and subjective image quality in terms of artifacts, gray-white matter differentiation, noise, visualization of posterior fossa structures, and need for repeat CT examination was visually evaluated by three neuroradiologists.

RESULTS

The median CT dose index and dose-length product values were significantly lower after than before training in all age groups (27 mGy and 338 mGy ∙ cm vs 107 mGy and 1444 mGy ∙ cm in the 0- to 4-year-old group, 41 mGy and 483 mGy ∙ cm vs 68 mGy and 976 mGy ∙ cm in the 5- to 9-year-old group, and 51 mGy and 679 mGy ∙ cm vs 107 mGy and 1480 mGy ∙ cm in the 10- to 14-year-old group; p < 0.001). The tube voltage and tube current-time values after training were significantly lower than the levels before training (p < 0.001). Subjective posttraining image quality was not inferior to pretraining levels for any item except noise (p < 0.05), which, however, was never diagnostically unacceptable.

CONCLUSION

Radiologic staff training can be effective in reducing radiation dose while preserving diagnostic image quality in pediatric head CT examinations.

Radiation exposure from head computed tomography scans in pediatric trauma

BACKGROUND

We have previously reported that children receive significantly less radiation exposure after abdominal and/or pelvis computed tomography (CT) scanning for acute appendicitis when performed at our children's hospital (CH) rather than at outside hospitals (OH). In this study, we compare the amount of radiation children receive from head CTs for trauma done at OH versus those at our CH.

METHODS

A retrospective chart review was performed on all children transferred to our hospital after receiving a head CT for trauma at an OH between July 2012 and December 2012. These children were then blindly case matched based on date, age, and gender to children at our CH.

RESULTS

There were 50 children who underwent head CT scans for trauma at 28 OH. There were 21 females and 29 males in each group. Average age was 7.01 ± 0.5 y at the OH and 7.14 ± 6.07 at our CH (P = 0.92). Average weight was 30.81 ± 4.69 kg at the OH and 32.69 ± 27.21 kg at our CH (P = 0.81). Radiation measures included dose length product (671.21 ± 22.6 mGycm at OH versus 786.28 ± 246.3 mGycm at CH, P = 0.11) and CT dose index (53.4 ± 2.26 mGy at OH versus 49.2 ± 12.94 mGy at CH, P = 0.56).

CONCLUSIONS

There is no significant difference between radiation exposure secondary to head CTs for traumatic injuries performed at OH and those at a dedicated CH.

Major clinical features of synostotic occipital plagiocephaly: mechanisms of cranial deformations

PURPOSE

The clinical diagnosis of most common single-suture craniosynostosis is easily set, based on the stereotype of deformities and knowledge of the mechanisms of cranial deformations. However, synostosis of unilateral lambdoid suture, probably due to its lower incidence and similarity with other non-synostotic deformities affecting the posterior portion of the skull, makes its clinical diagnosis more difficult and imprecise. The aim of this study is to evaluate the most easily and accurate clinical characteristics to be recognized in the synostotic occipital plagiocephaly.

METHODS

This study consisted of clinical evaluation of eight patients with synostotic occipital plagiocephaly, whose diagnosis was further corroborated by computed tomography.

RESULTS

We identified the following: unilateral occipital flattening in eight out of eight patients (100 %), bulging of ipsilateral mastoid process in eight out of eight (100 %), "edge effect" of ipsilateral lambdoid suture in eight out of eight (100 %), inferior deviation of the ear in eight out of eight (100 %), "Dumbo" ears in eight out of eight (100 %), horizontal slant of the bimastoid line in seven out of eight (87.5 %), tilt of the head viewed from behind in seven out of eight (87.5 %), trapezoidal contour of the skull in top view in six out of eight (75 %), contralateral parietal bossing in six out of eight (75 %), and bossing of the contralateral forehead three out of eight (37.5 %).

CONCLUSIONS

The most important clinical features specific to the clinical diagnosis of synostotic occipital plagiocephaly, not present in the positional posterior plagiocephaly, were bulging of the ipsilateral mastoid process, edge effect of the synostotic lambdoid suture, tilt of the head, and slant of the bimastoid line viewed from behind, inferior deviation of the ear, and contralateral parietal bossing.

Radiation exposure - how do CT scans for appendicitis compare between a free standing children's hospital and non-dedicated pediatric facilities?

BACKGROUND

We compare the amount of radiation children receive from CT scans performed at non-dedicated pediatric facilities (OH) versus those at a dedicated children's hospital (CH).

METHODS

Using a retrospective chart review, all children undergoing CT scanning for appendicitis at an OH were compared to children undergoing CT imaging for appendicitis at a CH between January 2011 and November 2012.

RESULTS

One hundred sixty-three children underwent CT scans at 42 different OH. Body mass index was similar between the two groups (21.00±6.49kg/m(2), 19.58±5.18kg/m(2), P=0.07). Dose length product (DLP) was 620±540.3 at OH and 253.78±211.08 at CH (P < 0.001). OH CT scans accurately diagnosed appendicitis in 81%, while CT scans at CH were accurate in 95% (P=0.026). CTDIvol was recorded in 65 patients with subset analysis showing CTDIvol of 16.98±15.58 and 4.89±2.64, a DLP of 586.25±521.59 and 143.54±41.19, and size-specific dose estimate (SSDE) of 26.71±23.1 and 3.81±2.02 at OH and CH, respectively (P<0.001).

CONCLUSION

Using SSDE as a marker for radiation exposure, children received 86% less radiation and had improved diagnostic accuracy when CT scans are performed at a CH.

Indications and overuse of computed tomography in minor head trauma

Background:

Computed Tomography (CT) is a useful diagnostic technology, particularly in accident and emergency departments.

Objectives:

To identify a comprehensive list of indications for application of CT in patients with minor head trauma (MHT) and to determine appropriateness of its use on the basis of this list.

Materials and Methods:

A cross-sectional study was conducted in three Imaging centers in Tehran. A panel of experts developed a list of CT indications for MHT by reviewing documents. A pre-structured checklist was designed and incorporated into a structured form. Four hundred consecutive patients referring to three imaging centers for performing CT due to MHT completed the questionnaire.

Results:

Of 400 patients who underwent CT after MHT, 187 (46.8%) patients had Glasgow coma scale (GCS) score of 13 or 14 at two hours post-trauma and 37 (19.8%) of these patients did not have any indication of imaging. In addition, 213 (53.2%) patients had GCS score of 15 out of which 110 (51.6%) patients did not have any indication of imaging. Patients with a GCS score of 15 had a noticeably lower proportion of abnormal CT results in comparison to patients with a GCS score of 13 or 14, (odds ratio, 19.07; 95% confidence interval, 6.74-54.00; and P < 0.001). There was a statistically significant association between abnormal CT results and the presence of indications including vomiting, dangerous mechanism of injury, visible signs of trauma above the clavicles, signs of skull base fracture, and suspected skull fracture (P < 0.001).

Conclusions:

On average, about 37% of the patients with MHT referring to the emergency departments had no indication of CT and approximately 86.5% of CT results were normal. Improving this situation can result in a significant saving in health care costs.

Outcomes of children with suspected appendicitis and incompletely visualized appendix on ultrasound

OBJECTIVES

The objective was to review the clinical outcomes of children with suspected appendicitis after an ultrasound (US) examination fails to fully visualize the appendix, the diagnostic characteristics of US in children with suspected appendicitis, and the predictive value of secondary signs of appendicitis when the appendix is not fully visualized.

METHODS

This was a retrospective health record review of children aged 3 to 17 years presenting to a tertiary pediatric emergency department (ED) with suspected appendicitis. Descriptive statistics and diagnostic test characteristics are reported.

RESULTS

Overall, 968 children had US. The appendix was fully visualized in 442 cases (45.7%), and 526 (54.3%) children had incompletely visualized appendices. The disposition of those with incompletely visualized appendices were as follows: 59.1% were discharged home, 10.5% went directly to the operating room, and 30.4% were admitted to the hospital for further observation. Of those discharged home based on clinical findings after incompletely visualized appendices, fewer than 0.3% ended up having appendicitis. Ultimately 15.6% of children with incompletely visualized appendices had pathology-confirmed appendicitis. The sensitivity and specificity of US for children with fully visualized appendices were 99.5% (95% confidence interval [CI] = 96.7% to 100%) and 81.3% (95% CI = 75.2% to 86.2%), respectively. The sensitivity and specificity for the presence of any secondary sign in diagnosing appendicitis were 40.2% (95% CI = 29.6% to 51.7%) and 90.6% (95% CI = 87.5% to 93.2%), respectively.

CONCLUSIONS

Children with incompletely visualized appendices on US can be safely discharged home based on clinical findings with an acceptable rate of missed appendicitis. Children with nonreassuring clinical examinations following incompletely visualized appendices on US may benefit from further imaging studies prior to appendectomy, to reduce the rate of negative appendectomy. While the presence of secondary signs of inflammation can be used to rule in appendicitis, statistical strength to rule out appendicitis in the absence of secondary signs is insufficient.

Optimization of hybrid iterative reconstruction level in pediatric body CT

OBJECTIVE

The objective of our study was to attempt to optimize the level of hybrid iterative reconstruction (HIR) in pediatric body CT.

MATERIALS AND METHODS

One hundred consecutive chest or abdominal CT examinations were selected. For each examination, six series were obtained: one filtered back projection (FBP) and five HIR series (iDose(4)) levels 2-6. Two pediatric radiologists, blinded to noise measurements, independently chose the optimal HIR level and then rated series quality. We measured CT number (mean in Hounsfield units) and noise (SD in Hounsfield units) changes by placing regions of interest in the liver, muscles, subcutaneous fat, and aorta. A mixed-model analysis-of-variance test was used to analyze correlation of noise reduction with the optimal HIR level compared with baseline FBP noise.

RESULTS

One hundred CT examinations were performed of 88 patients (52 females and 36 males) with a mean age of 8.5 years (range, 19 days-18 years); 12 patients had both chest and abdominal CT studies. Radiologists agreed to within one level of HIR in 92 of 100 studies. The mean quality rating was significantly higher for HIR than FBP (3.6 vs 3.3, respectively; p < 0.01). HIR caused minimal (0-0.2%) change in CT numbers. Noise reduction varied among structures and patients. Liver noise reduction positively correlated with baseline noise when the optimal HIR level was used (p < 0.01). HIR levels were significantly correlated with body weight and effective diameter of the upper abdomen (p < 0.01).

CONCLUSION

HIR, such as iDose(4), improves the quality of body CT scans of pediatric patients by decreasing noise; HIR level 3 or 4 is optimal for most studies. The optimal HIR level was less effective in reducing liver noise in children with lower baseline noise.

Ultrasonography/MRI versus CT for diagnosing appendicitis

BACKGROUND

Cross-sectional imaging increases accuracy in diagnosing appendicitis. We hypothesized that a radiation-free imaging pathway of ultrasonography selectively followed by MRI would not change clinical end points compared with computed tomography (CT) for diagnosis of acute appendicitis in children.

METHODS

We retrospectively reviewed children (<18 years old) who had diagnostic imaging for suspected acute appendicitis between November 2008 and October 2012. Before November 2010 CT was used as the primary imaging modality (group A); subsequently, ultrasonography was the primary imaging modality followed by MRI for equivocal findings (group B). Data collected included time from triage to imaging and treatment and results of imaging and pathology.

RESULTS

Six hundred sixty-two patients had imaging for suspected appendicitis (group A = 265; group B = 397, of which 136 [51%] and 161 [41%], respectively, had positive imaging for appendicitis). Negative appendectomy rate was 2.5% for group A and 1.4% for group B. Perforation rate was similar for both groups. Time from triage to antibiotic administration and operation did not differ between groups A and B. There was higher proportion of positive imaging and appendectomies in group A and thus more negative imaging tests in group B (ultrasonography and MRI), but diagnostic accuracy of the 2 imaging pathways was similar.

CONCLUSIONS

In children with suspected acute appendicitis, a radiation-free diagnostic imaging of ultrasonography selectively followed by MRI is feasible and comparable to CT, with no difference in time to antibiotic administration, time to appendectomy, negative appendectomy rate, perforation rate, or length of stay.

Radial differential interior tomography and its image reconstruction with differentiated backprojection and projection onto convex sets

PURPOSE

Interior tomography has been recognized as one of the most effective approaches in computed tomography (CT) to reduce radiation dose rendered to patients. In this work, the authors propose and evaluate an imaging method of radial differential interior tomography.

METHODS

In interior tomography, an x-ray beam is collimated to only irradiate the region of interest (ROI) with suspected lesions while the surrounding area∕volume of normal tissues∕organs is spared. In the proposed imaging method of radial differential interior tomography, the outcome is a ROI image that has gone through a radial differential filtering. The image reconstruction algorithm for the radial differential interior tomography is kept in the fashion of differentiated backprojection and projection onto convex sets, but the required a priori knowledge in a small round area becomes zero and may be more readily available in practice.

RESULTS

Using the projection data simulated by computer and acquired by CT scanner, the authors evaluate and verify the performance of the proposed radial differential interior tomography method and its associated image reconstruction algorithm. The preliminary results show that the proposed imaging method can generate an image that is the radial differentiation of a conventional tomographic image and is robust over noise that inevitably exist in practice.

CONCLUSIONS

It is believed that the proposed imaging method may find its utility in advanced clinical applications wherein a ROI-based image processing and analysis is required for lesion visualization, characterization, and diagnosis.

[Chest computed tomography in children: indications, efficiency and effective dose]

INTRODUCTION

New multidetector row computed tomography (CT) has made the imaging of younger children more feasible and extending CT indications to a wide range of pediatric respiratory diseases in the last few years. However, CT is a source of radiation exposure. The aim of this study was to evaluate the main indications and the contribution of chest CT in pediatric pulmonology as well as induced radiation.

METHODS

This was an observational, prospective study. Children whose chest CTs were analyzed during multidisciplinary meetings (radiologist, pulmonary pediatrician) were included from November 2009 to April 2010. We collected demographic data, CT results, contribution of CT to diagnosis and management, and radiation doses (dose-length product [DLP] and effective dose). Radiation doses were compared according to the CT scans (Lille University Hospital with 128-slice dual-source CT or Lille University Hospital single-source 64-slice CT, or CT performed outside the university hospital).

RESULTS

One hundred thirty-five patients were included. The mean age was 6.4 years old. The main indications were analysis of bronchial disease (44%), infectious disease (16%), interstitial disease (14%), or a malformation (9%). The aim of CT was diagnosis (61%) or follow-up of previous lung diseases (39%). Diagnosis chest-CT directly contributed to diagnosis in 48% of cases and to treatment in 24%. Follow-up CT contributed to diagnosis in 38% and treatment in 19% of cases. DLP and effective doses were significantly lower for CT performed in the university hospital, especially with the 128-slice CT compared to the others (P<0.001). The effective doses were: 128-slice CT, 0.61 mSv ± 0.32; 64-slice CT, 1.24 mSv ± 0.97; outside university hospital, 2.56 mSv ± 1.98.

CONCLUSION

This study confirms the role played by chest CT in children, which contributes to diagnosis and management of lung diseases. The main concern of CT application, especially in children, is the radiation burden. Children are more susceptible to the effects of radiation than adults and have a longer life expectancy to develop complications. Both radiologists and pediatricians should be aware of a potential risk and have to conjugate their efforts in reducing this risk. The wide range of radiation doses in this study for the same CT procedures underlines the extensive efforts still needed to limit radiation exposure in children.

Paediatric computed tomography radiation dose: A review of the global dilemma

Computed tomography (CT) has earned a well-deserved role in diagnostic radiology, producing cross-sectional and three-dimensional images which permit enhanced diagnosis of many pathogenic processes. The speed, versatility, accuracy, and non-invasiveness of this procedure have resulted in a rapid increase in its use. CT imaging, however, delivers a substantially higher radiation dose than alternative imaging methodologies, particularly in children due to their smaller body dimensions. In addition, CT use in children produces an increased lifetime risk of cancer, as children's developing organs and tissues are inherently more vulnerable to cellular damage than those of adults. Though individual risks are small, the increasing use of CT scans in children make this an important public health problem. Various organizations have recommended measures to minimize unnecessary exposures to radiation through CT scanning. These include elimination of multiple or medically unnecessary scans, development of patient-specific dosing guidelines, and use of alternative radiographic methodology wherever possible. Another important factor in excessive CT exposures, however, is a documented lack of awareness among medical practitioners of the doses involved in CT usage as well as its significant potential dangers. This review examines the effects of paediatric CT radiation, discusses the level of medical practitioner awareness of these effects, and offers recommendations on alternative diagnostic methods and practitioner education.

Cranial computed tomography utilization for suspected ventriculoperitoneal shunt malfunction in a pediatric emergency department

BACKGROUND

Computed tomography (CT) scan, the largest medical source of ionizing radiation in the United States, is used to test for failure of ventricular peritoneal shunts.

STUDY OBJECTIVES

To quantify the exposure to cranial CT scans in pediatric patients presenting with symptoms of shunt malfunction, and to measure the association of signs and symptoms with clinical shunt malfunction and the need for neurosurgical intervention within 30 days of presentation.

METHOD

This was a quality improvement study evaluating a pathway used by providers in a tertiary care pediatric emergency department with 85,000 patient visits per year, by retrospective chart review of 223 patient visits for suspected shunt malfunction. We determined the median CT scan per patient per year and the association of signs and symptoms on the pathway with radiological signs of shunt failure and neurosurgical intervention within 30 days of scan.

RESULTS

The median exposure was 2.6 (interquartile range 1.44-4.63) scans per patient per year. Among 11 signs and symptoms, none was associated with radiologic shunt failure. Neurosurgical intervention within 30 days was positively associated with bulging fontanelle (adjusted odds ratio [AOR] 11.78; 95% confidence interval [CI] 1.67-83.0) and behavioral change (AOR 3.01; 95% CI 1.14-7.93), and negatively associated with seizure (AOR 0.13; 95% CI 0.02-0.79) and fever (AOR 0.15; 95% CI 0.04-0.55).

CONCLUSIONS

Patients with ventricular peritoneal shunts underwent many cranial CT scans each year. None of the signs or symptoms included on the clinical pathway was predictive of changes on CT scan.

Do clinical outcomes suffer during transition to an ultrasound-first paradigm for the evaluation of acute appendicitis in children?

OBJECTIVE

The objective of our study was to examine whether the rate of complicated appendicitis and the hospital length of stay (LOS) increased during the transition to an ultrasound-first paradigm for the imaging evaluation of acute appendicitis.

MATERIALS AND METHODS

All pediatric patients with surgically proven appendicitis from 2005 to 2011 were identified by searching the hospital billing database for the discharge diagnosis codes for simple appendicitis (ICD-9 [International Classification of Diseases, 9th revision] code 540.9) and complicated appendicitis (ICD-9 codes 540.0 and 540.1). Annual trends of the proportions of these patients who underwent ultrasound and CT were determined and plotted for the study period. Correlation of complicated appendicitis and median hospital LOS with calendar year was assessed using the Spearman (ρ) rank correlation test. RESULTS. Eight hundred four patients met the inclusion criteria. The percentage of patients who underwent CT only showed a moderate downward association with year (ρ = -0.32, p < 0.01), and the percentage of patients who underwent ultrasound first showed a moderate upward trend (ρ = 0.44, p < 0.01). The percentage of patients with ultrasound as the only study performed before appendectomy increased moderately over the 7-year study period (ρ = 0.33, p < 0.01). The percentage of patients with complicated appendicitis and the median hospital LOS did not increase significantly over the study duration (ρ = -0.01, p = 0.74 and ρ = -0.04, p = 0.25, respectively).

CONCLUSION

The transition to an ultrasound-first pathway for the imaging workup of acute appendicitis in children occurred without evidence of a corresponding increase in the proportion of patients with complicated appendicitis or in the median hospital LOS.

Radiation risks associated with serial imaging in colorectal cancer patients: Should we worry?

To provide an overview of the radiation related cancer risk associated with multiple computed tomographic scans required for follow up in colorectal cancer patients. A literature search of the PubMed and Cochrane Library databases was carried out and limited to the last 10 years from December 2012. Inclusion criteria were studies where computed tomographic scans or radiation from other medical imaging modalities were used and the risks associated with ionizing radiation reported. Thirty-six studies were included for appraisal with no randomized controlled trials. Thirty-four of the thirty-six studies showed a positive association between medical imaging radiation and increased risk of cancer. The radiation dose absorbed and cancer risk was greater in children and young adults than in older patients. Most studies included in the review used a linear, no-threshold model to calculate cancer risks and this may not be applicable at low radiation doses. Many studies are retrospective and ensuring complete follow up on thousands of patients is difficult. There was a minor increased risk of cancer from ionizing radiation in medical imaging studies. The radiation risks of low dose exposure (< 50 milli-Sieverts) are uncertain. A clinically justified scan in the context of colorectal cancer is likely to provide more benefits than harm but current guidelines for patient follow up will need to be revised to accommodate a more aggressive approach to treating metastatic disease.

Using patient characteristics to predict usefulness of abdominal computed tomography in children

OBJECTIVE

The study goal was to determine whether clinical symptoms, physical findings, or laboratory values predict the usefulness of abdominal computed tomography (CT) scans in children.

METHODS

We conducted a retrospective review of pediatric patients who received an abdominal CT scan between June 2009 and November 2011 at an urban medical center. A panel of pediatric hospitalists independently categorized each CT read as: (1) necessary for diagnosis; (2) unnecessary but helpful for diagnosis; or (3) neither necessary nor helpful for diagnosis. Two multiple logistic regression models examined 21 clinical variables to assess their ability to differentiate between: (1) necessary and unnecessary CT scans; and (2) helpful and unhelpful CT scans.

RESULTS

A total of 399 CT scans were analyzed. Seventy (18%) of these were categorized as necessary, 103 (26%) as unnecessary but helpful, and 226 (57%) as neither necessary nor helpful. Three variables were strongly correlated with necessary CT scans: leukocytosis, peritoneal signs, and male gender. The probability of a CT scan being necessary was 57% in patients with all 3 findings and 8% in those with none. Three variables were also strongly correlated with unnecessary but helpful CT scans: history of abdominal surgery, tachypnea, and leukocytosis. The probability of a CT scan being helpful was 84% in patients with all 3 findings and 35% in those with none of the 3 findings.

CONCLUSIONS

The majority of abdominal CT scans were unnecessary and unhelpful. Knowing which clinical variables correlate strongly with necessary or helpful abdominal CT scans may assist clinicians in deciding whether to order this test; however, the predictive power of these variables remains relatively low.

Is computed tomography necessary to determine liver injury in pediatric trauma patients with negative ultrasonography?

PURPOSE

Abdominal trauma is the third most common cause of all trauma-related deaths in children. Liver injury is the second most common, but the most fatal injury associated with abdomen trauma. Because the liver enzymes have high sensitivity and specificity, the use of tomography has been discussed for accurate diagnosis of liver injury.

METHODS

Our study was based on retrospective analyses of hemodynamically stabil patients under the age of 18 who were admitted to the emergency department with blunt abdominal trauma.

RESULTS

Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were significantly higher as a result of liver injury. In the patients whose AST and ALT levels were lower than 40 IU/L, no liver injury was observed in the contrast-enhanced computed tomography (CT). No liver injury was detected in the patients with AST levels lower than 100 IU/L. Liver injury was detected with contrast-enhanced CT in only one patient whose ALT level was lower than 100 IU/L, but ultrasonography initially detected liver injury in this patient.

CONCLUSIONS

According to our findings, abdominal CT may not be necessary to detect liver injury if the patient has ALT and AST levels below 100 IU/L with a negative abdominal USG at admission and during follow-up.

Improving low-dose blood-brain barrier permeability quantification using sparse high-dose induced prior for Patlak model

Blood-brain barrier permeability (BBBP) measurements extracted from the perfusion computed tomography (PCT) using the Patlak model can be a valuable indicator to predict hemorrhagic transformation in patients with acute stroke. Unfortunately, the standard Patlak model based PCT requires excessive radiation exposure, which raised attention on radiation safety. Minimizing radiation dose is of high value in clinical practice but can degrade the image quality due to the introduced severe noise. The purpose of this work is to construct high quality BBBP maps from low-dose PCT data by using the brain structural similarity between different individuals and the relations between the high- and low-dose maps. The proposed sparse high-dose induced (shd-Patlak) model performs by building a high-dose induced prior for the Patlak model with a set of location adaptive dictionaries, followed by an optimized estimation of BBBP map with the prior regularized Patlak model. Evaluation with the simulated low-dose clinical brain PCT datasets clearly demonstrate that the shd-Patlak model can achieve more significant gains than the standard Patlak model with improved visual quality, higher fidelity to the gold standard and more accurate details for clinical analysis.

Risks and management of radiation exposure

High-energy ionizing radiation is harmful. Low-level exposure sources include background, occupational, and medical diagnostics. Radiation disaster incidents include radioactive substance accidents and nuclear power plant accidents. Terrorism and international conflict could trigger intentional radiation disasters that include radiation dispersion devices (RDD) (a radioactive dirty bomb), deliberate exposure to industrial radioactive substances, nuclear power plant sabotage, and nuclear weapon detonation. Nuclear fissioning events such as nuclear power plant incidents and nuclear weapon detonation release radioactive fallout that include radioactive iodine 131, cesium 137, strontium 90, uranium, plutonium, and many other radioactive isotopes. An RDD dirty bomb is likely to spread only one radioactive substance, with the most likely substance being cesium 137. Cobalt 60 and strontium 90 are other RDD dirty bomb possibilities. In a radiation disaster, stable patients should be decontaminated to minimize further radiation exposure. Potassium iodide (KI) is useful for iodine 131 exposure. Prussian blue (ferric hexacyanoferrate) enhances the fecal excretion of cesium via ion exchange. Ca-DTPA (diethylenetriaminepentaacetic acid) and Zn-DTPA form stable ionic complexes with plutonium, americium, and curium, which are excreted in the urine. Amifostine enhances chemical and enzymatic repair of damaged DNA. Acute radiation sickness ranges in severity from mild to lethal, which can be assessed by the nausea/vomiting onset/duration, complete blood cell count findings, and neurologic symptoms.

Effect of tube voltage on CT noise levels in different phantom sizes

OBJECTIVE

The purpose of this study was to determine the effect of lowering tube voltage on dose and noise in cylindric water phantoms to optimize quality and decrease the radiation dose for body CT.

MATERIALS AND METHODS

We performed CT on cylindric water phantoms with diameters of 10, 20, 25, and 30 cm, simulating the abdomen of an infant, child, adolescent, and adult. We used tube voltages of 120, 100, and 80 kVp. The CT dose index (32-cm reference) ranged from 1 to 10 mGy in 10- and 20-cm phantoms and from 2 to 20 mGy in the 25- and 30-cm phantoms. The noise was measured at the center and periphery of the scans. Central and peripheral doses were measured in 16- and 32-cm CT dose index phantoms, and the ratio of central to peripheral doses was calculated.

RESULTS

At the same noise levels, there was no significant increase in dose in 10-cm cylindric water phantoms when tube voltage was decreased to either 80 or 100 kVp. In 20-, 25-, and 30-cm phantoms, there was a 1-6% increase in dose when tube voltage was decreased to 100 kVp. Central-to-peripheral noise ratios increased 7-37% with increased phantom size. The measured peripheral dose increased as much as 5%.

CONCLUSION

Our findings support the practice of lowering tube voltage to 80 kVp for imaging of infants and to 100 kVp for imaging of older children. The increase in peripheral dose with decreased tube voltage is minimal and is unlikely to cause substantial change in the effective dose.

Concurrent septic arthritis and osteomyelitis in children

INTRODUCTION

Septic arthritis and osteomyelitis can both independently cause substantial morbidity. With concomitant septic arthritis and osteomyelitis, the septic arthritis may be treated without knowledge of the adjacent osteomyelitis resulting in delayed treatment. This study aims to identify factors that may help to diagnosis concurrent infections (CI) earlier.

METHODS

A retrospective chart review of 200 patients with septic arthritis was performed. Patients with CI were compared with patients with septic arthritis alone using tests determined by the nature of the variable being analyzed (the χ test, the Fisher exact test, the Cochran-Armitage trend test, and the Kruskal-Wallis test.).

RESULTS

Two hundred patients were eligible and analyzed, of which 43 (21.5%) had CI. On the basis of age, CI were most common in newborns and adolescents (P<0.0001). On the basis of location, 72% of shoulder infections (P<0.0001) were concurrent, whereas <50% of elbows, hips, knees, and ankle were CI. The most common infective organism was methicillin-sensitive Staphylococcus aureus (P<0.0001). CI were significantly associated with increased median (6) days of clinical symptoms before presentation (P<0.0001), increased duration of median (6) days of hospital stay (P<0.0001), increased number of operative procedures (P=0.005), and increased need for ICU admission (P=0.024).

CONCLUSIONS

Utilizing advanced imaging (CT scan, bone scan, and/or MRI) in patients with septic arthritis who are younger than 4 months of age, between ages 13 and 20 years, with septic arthritis involving the shoulder, and with symptoms for more than 6 days may shorten hospital stays, decrease the number of operative procedures required, and possibly limit infection-related sequelae by identifying CI earlier.

LEVEL OF EVIDENCE

III.

CT for pediatric, acute, minor head trauma: clinician conformity to published guidelines

BACKGROUND AND PURPOSE

In 2001, pediatric radiologists participating in a panel discussion on CT dose reduction suggested that approximately 30% of head CT examinations were performed unnecessarily. With increasing concern regarding radiation exposure to children and imaging costs, this claim warrants objective study. The purpose of this study was to test the null hypothesis that 30% of head CT studies for clinical evaluation of children with acute, minor head trauma do not follow established clinical guidelines.

MATERIALS AND METHODS

Retrospective review of 182 consecutive patients with acute, minor head trauma from February 2009 to January 2010 at a tertiary care children's hospital emergency department was performed, and clinician adherence to published clinical guidelines for children younger than 2 years and children 2-20 years of age was determined. The binomial test was used for a null hypothesis of 30% unnecessary examinations against the actual percentage of head CTs deemed unnecessary on the basis of established guidelines. Statistical testing was performed for children younger than 2 years and 2-20 years of age.

RESULTS

For children younger than 2 years of age, 2 of 78 (2.6%; 95% CI, 0.5%-8.3%) and, for children 2-20 years of age, 12 of 104 (11.5%; CI, 6.4%-18.7%) did not conform to established guidelines. These percentages were significantly less than the hypothesized value of 30% (P < .001).

CONCLUSIONS

Clinician conformity to published guidelines for use of head CT in acute, minor head trauma is better than suggested by a 2001 informal poll of pediatric radiologists.

"Simple febrile seizures plus (SFS+)": more than one febrile seizure within 24 hours is usually okay

This study aimed to investigate whether children with recurrent febrile seizures within a 24-hour period need to be worked up differently from children with simple febrile seizures. Inclusion criteria included the following: (i) children with first seizure cluster between 4 months and 3 years of age, (ii) children who had more than one febrile seizure within 24 hours, and (iii) children who returned to baseline between and after each event. Thirty-two patients met the inclusion criteria over a 3-year period. All patients underwent brain CT and/or MRI and EEG. All head CTs were normal. Two children had abnormal MRI findings - both benign: one is thought to represent postictal changes, and the other one is an incidental arachnoid cyst. Of the 4 abnormal EEGs, one showed epileptiform discharges, while the others showed generalized ictal or postictal features. We propose the term "simple febrile seizures plus (SFS+)" to describe children who have more than one seizure within 24 hours but who are otherwise not different in presentation from children with SFS.

Parental knowledge of radiation exposure in medical imaging used in the pediatric emergency department

OBJECTIVES

We sought to quantify the knowledge base among parents and legal guardians presenting to our pediatric emergency department regarding radiation exposure during medical imaging and potential risks to children resulting from ionizing radiation. We sought to examine if a child's previous exposure to medical imaging changed caregiver knowledge base and discern caregivers' preference for future education on this topic.

METHODS

A prospective convenience sample survey was performed of caregivers who presented with their child to our tertiary pediatric emergency department. Parents or legal guardians (18-89 years) who accompanied a child (0-17 years) were eligible for inclusion and approached for enrollment. A structured questionnaire was administered by trained interviewers, and a chart review was conducted to ascertain if their child had a history of previous imaging.

RESULTS

Sixty percent of caregivers interviewed (n = 205 of 340) did not associate any long-term negative effects with medical imaging. Among participants who did express a perceived risk from medical imaging radiation exposure, only 50% could indicate a known negative effect from exposure. We found no significant association between a child having had documented imaging studies and awareness of long-term negative effects (P = 0.22). Participants preferred to learn more about this topic from an Internet-based resource (50%), informational pamphlet (38%), or via treating physician (33%).

CONCLUSIONS

Parents and legal guardians are largely unaware that exposure to radiation during medical imaging carries an inherent risk for their child. Health care providers wishing to educate caregivers should utilize reliable Internet sources, educational pamphlets, and direct communication.

Cancer risk in 680,000 people exposed to computed tomography scans in childhood or adolescence: data linkage study of 11 million Australians

OBJECTIVE

To assess the cancer risk in children and adolescents following exposure to low dose ionising radiation from diagnostic computed tomography (CT) scans.

DESIGN

Population based, cohort, data linkage study in Australia. COHORT MEMBERS: 10.9 million people identified from Australian Medicare records, aged 0-19 years on 1 January 1985 or born between 1 January 1985 and 31 December 2005; all exposures to CT scans funded by Medicare during 1985-2005 were identified for this cohort. Cancers diagnosed in cohort members up to 31 December 2007 were obtained through linkage to national cancer records.

MAIN OUTCOME

Cancer incidence rates in individuals exposed to a CT scan more than one year before any cancer diagnosis, compared with cancer incidence rates in unexposed individuals.

RESULTS

60,674 cancers were recorded, including 3150 in 680,211 people exposed to a CT scan at least one year before any cancer diagnosis. The mean duration of follow-up after exposure was 9.5 years. Overall cancer incidence was 24% greater for exposed than for unexposed people, after accounting for age, sex, and year of birth (incidence rate ratio (IRR) 1.24 (95% confidence interval 1.20 to 1.29); P<0.001). We saw a dose-response relation, and the IRR increased by 0.16 (0.13 to 0.19) for each additional CT scan. The IRR was greater after exposure at younger ages (P<0.001 for trend). At 1-4, 5-9, 10-14, and 15 or more years since first exposure, IRRs were 1.35 (1.25 to 1.45), 1.25 (1.17 to 1.34), 1.14 (1.06 to 1.22), and 1.24 (1.14 to 1.34), respectively. The IRR increased significantly for many types of solid cancer (digestive organs, melanoma, soft tissue, female genital, urinary tract, brain, and thyroid); leukaemia, myelodysplasia, and some other lymphoid cancers. There was an excess of 608 cancers in people exposed to CT scans (147 brain, 356 other solid, 48 leukaemia or myelodysplasia, and 57 other lymphoid). The absolute excess incidence rate for all cancers combined was 9.38 per 100,000 person years at risk, as of 31 December 2007. The average effective radiation dose per scan was estimated as 4.5 mSv.

CONCLUSIONS

The increased incidence of cancer after CT scan exposure in this cohort was mostly due to irradiation. Because the cancer excess was still continuing at the end of follow-up, the eventual lifetime risk from CT scans cannot yet be determined. Radiation doses from contemporary CT scans are likely to be lower than those in 1985-2005, but some increase in cancer risk is still likely from current scans. Future CT scans should be limited to situations where there is a definite clinical indication, with every scan optimised to provide a diagnostic CT image at the lowest possible radiation dose.

Imaging, radiation exposure, and attributable cancer risk for neonates with necrotizing enterocolitis

PURPOSE

Neonates with necrotizing enterocolitis (NEC) receive numerous radiologic investigations that potentially increase their lifetime cancer mortality risk. We evaluated our radiologic practice pattern for patients with NEC and estimated cumulative radiation exposure and lifetime cancer risk.

METHODS

Infants with NEC in a tertiary care NICU had patient demographics, imaging, treatments/interventions, and outcomes analyzed over 3 years. The number and type of imaging were recorded, including NEC-related imaging (thoraco-abdominal "babygrams" and abdominal radiographs), and all other imaging modalities. Patients were stratified by birth weight: group 1 (<750 g); group 2 (751-1500 g); and group 3 (>1501 g). Pre-existing normative data were used to calculate radiation exposure, absorption, and attributable cancer risk from NEC-related imaging.

RESULTS

Sixty-four neonates with 72 episodes of NEC were identified. Overall survival was 75.0%. When stratified by birth weight, mean abdominal radiographs and babygrams comprised 51%, 60%, and 74% of total imaging, giving median mGy doses of 2.1, 0.4, and 0.2, respectively. Compared to normative data, radiation dosing, and median cumulative cancer lifetime mortality risk increased by an average of 4.3× from baseline, with two cases documenting a 20-fold increase.

CONCLUSION

Neonates with NEC are exposed to significant amounts of radiation directly attributable to disease surveillance. Non-radiologic surveillance methods could significantly reduce radiation exposure and cancer risk in these infants.

The routine use of chest radiographs after chest tube removal in children who have had cardiac surgery

BACKGROUND

It is routine to obtain a chest radiograph (CXR) after removal of a chest tube (CT) to assess for pneumothorax. Retrospective studies have shown that clinical signs were present in most children with pneumothorax and were an indication for a CXR.

OBJECTIVE

Our objective was to determine if clinical indicators of pneumothorax are sufficient predictors of the need for CT reinsertion in children who have had a CT removed after cardiac surgery.

METHODS

The prospective study included a physical assessment before CT removal, using a two-person technique, which was repeated 2 hours after CT removal. Based on assessment findings, a decision was made regarding whether a CXR was indicated. The routine CXR was then obtained and read by a pediatric intensivist who was blinded to the decision of the investigator.

RESULTS

Sixty CTs were removed in 53 children. No false-positive predictions were made, because none of the children was predicted to have a pneumothorax requiring chest tube reinsertion, and none developed a significant pneumothorax (95% confidence interval: 0, 5%).

CONCLUSIONS

The low rate of pneumothoraces in this study may be been related to how the CT was placed in surgery, the type of CT used, or the method of removal. In this study the risk of developing a pneumothorax requiring CT reinsertion after CT removal was at most 5% and therefore low enough to consider obtaining a CXR for symptomatic children only.

Pediatric CT: strategies to lower radiation dose

OBJECTIVE

The introduction of MDCT has increased the utilization of CT in pediatric radiology along with concerns for radiation sequelae. This article reviews general principles of lowering radiation dose, the basic physics that impact radiation dose, and specific CT integrated dose-reduction tools focused on the pediatric population.

CONCLUSION

The goal of this article is to provide a comprehensive review of the recent literature regarding CT dose reduction methods, their limitations, and an outlook on future developments with a focus on the pediatric population. The discussion will initially focus on general considerations that lead to radiation dose reduction, followed by specific technical features that influence the radiation dose.

[Positron emission tomography/magnetic resonance: Present and future]

PET/MRI has recently been introduced onto the market after several years of research and development. The simple notion of combining the molecular capabilities of the PET and its difference available radiotracers with the excellent tissue resolution of the MRI and wide range of multiparametric imaging techniques has generated great expectations upon the possible uses of this technology. Many challenges must be worked out. However, the most urgent one is the derivation of the MRI-based attenuation correction map. This is especially true because the PET/CT has already demonstrated a huge clinical impact within oncology, neurology and cardiology during its short existence. Despite these difficulties, research is being carried out at a rapid pace in the clinical setting in order to find areas in which the PET/MRI is superior to other existing imaging modalities. In the few initial publications found up to date that have analyzed its clinical role, areas have been identified where PET/CT can migrate to PET/MRI, even if only to suppress the CT scan's ionizing radiation. Nonetheless, there are many theoretical applications in which the PET/MRI can further improve the field of diagnostic imaging. In this article, we will review those applications, the evidence existing regarding the MRI and PET that support those premises as well as that which we have learned in the short period of one year with our experience using the PET/MRI.

High-resolution MR imaging of the orbit in patients with retinoblastoma

Retinoblastoma is the most common intraocular childhood malignancy, with a prevalence of one in 18,000 children younger than 5 years old in the United States. In 80% of patients, retinoblastoma is diagnosed before the age of three, and in 95% of patients, retinoblastoma is diagnosed before the age of five. Although reports exist of retinoblastoma in adults, onset beyond 6 years of age is rare. Broadly, retinoblastoma may be classified into two groups: sporadic and heritable. In either case, the origin of the tumor is a biallelic mutation in primitive neuroepithelial cells. Although their details vary, several staging schemes are used to describe the extent of retinoblastoma according to the following four general criteria: intraocular location, extraocular (extraorbital) location, central nervous system disease, and systemic metastases. In the past decade, substantial changes have taken place in terms of staging and monitoring treatment in patients with retinoblastoma. Diagnosis and treatment of retinoblastoma involve a multidisciplinary approach, for which imaging is a vital component. Increasing awareness and concerns about the effects of radiation in patients with retinoblastoma have led to a shift away from external-beam radiation therapy and toward chemotherapy and locoregional treatment, as well as the establishment of magnetic resonance imaging as the most important imaging modality for diagnosis, staging, and treatment monitoring.

Pediatric traumatic brain injury and radiation risks: a clinical decision analysis

OBJECTIVE

To determine the optimal imaging strategy for young children with minor head injury considering health-related quality of life and radiation risk. In children with minor head trauma, the risk of missing a clinically important traumatic brain injury (ciTBI) must be weighed against the risk of radiation-induced malignancy from computed tomography (CT) to assess impact on public health.

STUDY DESIGN

We included children <2 years old with minor blunt head trauma defined by a Glasgow Coma Scale score of 14-15. We used decision analysis to model a CT-all versus no-CT strategy and assigned values to clinical outcomes based on a validated health-related quality of life scale: (1) baseline health; (2) non-ciTBI; (3) ciTBI without neurosurgery, death, or intubation; and (4) ciTBI with neurosurgery, death, or intubation >24 hours with probabilities from a prospective study of 10000 children. Sensitivity analysis determined the optimal management strategy over a range of ciTBI risk.

RESULTS

The no-CT strategy resulted in less risk with the expected probability of a ciTBI of 0.9%. Sensitivity analysis for the probability of ciTBI identified 4.8% as the threshold above which CT all becomes the preferred strategy and shows that the threshold decreases with less radiation. The CT all strategy represents the preferred approach for children identified as high-risk.

CONCLUSION

Among children <2 years old with minor head trauma, the no-CT strategy is preferable for those at low risk, reserving CT for children at higher risk.