Radiation, thoracic imaging, and children: radiation safety

Factors Associated With Bronchiolitis Guideline Nonadherence at US Children's Hospitals

BACKGROUND

The objective with this study was to explore factors associated with nonadherence to national bronchiolitis guidelines at 52 children's hospitals.

METHODS

We included patients 1 month to 2 years old with emergency department (ED) or admission encounters between January 2016 and December 2018 and bronchiolitis diagnoses in the Pediatric Health Information System database. We excluded patients with any intensive care, stay >7 days, encounters in the preceding 30 days, chronic medical conditions, croup, pneumonia, or asthma. Guideline nonadherence was defined as receiving any of 5 tests or treatments: bronchodilators, chest radiographs, systemic steroids, antibiotics, and viral testing. Nonadherence outcomes were modeled by using mixed effects logistic regression with random effects for providers and hospitals. Adjusted odds ratio (aOR) >1 indicates greater likelihood of nonadherence.

RESULTS

A total of 198 028 encounters were included (141 442 ED and 56 586 admission), and nonadherence was 46.1% (ED: 40.2%, admissions: 61.0%). Nonadherence increased with patient age, with both ED and hospital providers being more likely to order tests and treatments for children 12 to 24 months compared with infants 1 ot 2 months (ED: aOR, 3.39; 95% confidence interval [CI], 3.20-3.60; admissions: aOR, 2.97; CI, 2.79-3.17]). Admitted non-Hispanic Black patients were more likely than non-Hispanic white patients to receive guideline nonadherent care (aOR, 1.16; CI, 1.10-1.23), a difference driven by higher use of steroids (aOR, 1.29; CI, 1.17-1.41) and bronchodilators (aOR, 1.39; CI, 1.31-1.48). Hospital effects were prominent for viral testing in ED and admission encounters (intraclass correlation coefficient of 0.35 and 0.32, respectively).

CONCLUSIONS

Multiple factors are associated with national bronchiolitis guideline nonadherence.

Emergency Department Resource Use in Pediatric Pneumonia: Point-of-Care Lung Ultrasonography versus Chest Radiography

OBJECTIVES

Point-of-care lung ultrasonography (US) is an alternative to chest radiography for imaging of suspected community-acquired pneumonia (CAP) in children. We compared pediatric emergency department (ED) time metrics between children who received point-of-care lung US versus chest radiography. Secondary objectives were comparisons of health system costs and other resources in these imaging groups.

METHODS

This work was a retrospective matched cohort study of children aged 0 to 18 years in an academic urban pediatric ED who were imaged for suspected CAP with either point-of-care lung US or chest radiography.

RESULTS

A total of 202 patients (101 in each group) were included in the study. The point-of-care lung US group spent a mean of 75.9 (SE, 14.3) minutes less from physician assessment to discharge (P < .0001) and 60.9 (SE, 18.1) minutes less in the overall ED length of stay (P = .0008). Physician billings and facility fees were both significantly lower (P < .0001) in the point-of-care lung US group, for a mean health systems savings of CAN$187.1 (SE, CAN$21.9).

CONCLUSIONS

In children undergoing imaging for suspected CAP in our pediatric ED, point-of-care lung US by pediatric emergency medicine physicians was associated with decreased time and cost compared with chest radiography.

A comprehensive review of the literature on the biological effects from dental X-ray exposures

PURPOSE

Routine dental X-rays are among the most common sources of ionizing radiation exposure for healthy individuals globally, with 300 examinations/1000 individuals/year as documented by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) global survey of medical radiation usage and exposure. Furthermore, in the United States of America, an increased use of dental radiography is evident. However, with the shift from using film to digital image receptors, the dose of radiation per routine examination has decreased. Despite this, there remains public concern of dental X-rays. This continuing concern highlights the need to review the literature on biological and health effects related to exposure, from dental X-rays.

MATERIAL AND METHODS

This report presents studies investigating biological and health effects related to exposures using dental X-rays in patients and provides a critical evaluation. Relevant studies specific to dental X-rays are reviewed from 1970 and onward with the bulk data in this field resulting from epidemiological and biomonitoring studies.

RESULTS

While, most epidemiological studies suggest a possible correlation between head/neck related tumors and exposure to dental X-rays, evidence for causation is lacking. Biomonitoring studies suggest that exposure to low-level radiation such as that of dental radiography may not be a factor in inducing long-term chromosomal damage, but may result in localized cytotoxicity in the irradiated region of the mouth, with no long-term harm.

CONCLUSIONS

In general, the total number of studies is low and the majority of the data has been generated from poorly designed experiments. This review will highlight shortcomings that could influence outcomes and provide a more balanced interpretation that could impact the public perception and the level of public concern on the health effects resulting from dental X-rays.

Impact of Surveillance Imaging Modality on Survival After Recurrence in Patients With Favorable-Histology Wilms Tumor: A Report From the Children's Oncology Group

PURPOSE

The use of computed tomography (CT) for routine surveillance to detect recurrence in patients with Wilms tumor (WT) has increased in recent years. The utility of CT, despite increased risk and cost, to improve outcome for these patients is unknown. We conducted a retrospective analysis with patients enrolled in the fifth National Wilms Tumor Study (NWTS-5) to determine if surveillance with CT correlates with improved overall survival (OS) after recurrence compared with chest x-ray (CXR) and abdominal ultrasound (US).

PATIENTS AND METHODS

Overall, 281 patients with recurrent unilateral favorable-histology WT were reviewed to assess how WT recurrence was detected: sign/symptoms (SS), surveillance imaging (SI) with CT scan, or SI with CXR/US.

RESULTS

The estimated 5-year OS rate after relapse was 67% (95% CI, 61% to 72%). Twenty-five percent of recurrences were detected with SS; 48.5%, with CXR/US; and 26.5%, with CT. Patients with SS had a 5-year OS rate of 59% (95% CI, 46% to 72%) compared with 70% (95% CI, 63% to 77%; P = .23) for those detected by SI. Recurrences detected by CT had a shorter median time from diagnosis to recurrence (0.60 years) compared with SS (0.91 years) or CXR/US (0.86 years; P = .003). For recurrences detected by SI, more tumor foci at relapse ( P < .001) and size of the largest focus greater than 2 cm ( P = .02) were associated with inferior OS. However, there was no difference in OS after relapse when recurrence was detected by CT versus CXR/US (5-year OS rate, 65% v 73%; P = .20).

CONCLUSION

In patients with favorable-histology WT, elimination of CT scans from surveillance programs is unlikely to compromise survival but would result in substantial reduction in radiation exposure and health care costs.

Lung Ultrasound as First-Line Examination for the Diagnosis of Community-Acquired Pneumonia in Children

OBJECTIVES

The diagnosis of pediatric community-acquired pneumonia (CAP) is based on clinical criteria. Even though chest x-ray (CXR) is only recommended in severe cases, it is often requested from physicians in mild cases, thus increasing radiation exposure. Lung ultrasound (LUS) is not included in the diagnostic workup. The objective of this study was to evaluate the diagnostic performance of LUS against CXR.

METHODS

Children who presented to the emergency department with clinical signs suggesting CAP and had already been evaluated with a CXR were included in the study. Availability of a pediatric sonographer expert in LUS was also considered a criterion for participation. Chest x-ray and LUS were considered positive for CAP in cases of alveolar or interstitial pattern of disease. The diagnostic criterion standard was the ex post diagnosis of pneumonia, made by an independent senior expert pediatrician, after evaluation of the complete medical chart.

RESULTS

Sixty-nine children were enrolled in the study, with 66 of 69 positive for CAP. Receiver operating characteristic curve analysis results for CXR were 95.5% sensitivity and 100% specificity, whereas for LUS, sensitivity was reported 92.42% and specificity 100%. Comparison of the 2 receiver operating characteristic curves revealed no difference in the diagnostic value of the 2 methods for the diagnosis of pneumonia (P = 0.658). However, LUS classified more cases as alveolar disease compared with CXR.

CONCLUSIONS

Lung ultrasound plays a significant role in the detection of CAP, not inferior to CXR. The aim of this study was to encourage the use of ultrasound as a first-line examination for CAP in children.

Lung Ultrasonography: A Viable Alternative to Chest Radiography in Children with Suspected Pneumonia?

OBJECTIVE

To determine the interrater reliability (IRR) of lung ultrasonography (LUS) and chest radiography (CXR) and evaluate the accuracy of LUS compared with CXR for detecting pediatric pneumonia compared with chest computed tomography (CT) scan.

STUDY DESIGN

This was a prospective cohort study of children aged 3 months to 18 years with a CXR and LUS performed between May 1, 2012, and January 31, 2014 with or without a clinical diagnosis of pneumonia. Four pediatric radiologists blinded to clinical information reported findings for the CXR and LUS images. IRR was estimated for 50 LUS and CXR images. The main outcome was the finding from CT ordered clinically or the probability of the CT finding for patients clinically requiring CT. Two radiologists reviewed CT scans to determine an overall finding. Latent class analysis was used to evaluate the sensitivity and specificity for findings (eg, consolidation) for LUS and CXR compared with CT.

RESULTS

Of the 132 patients in the cohort, 36 (27%) had CT performed for a clinical reason. Pneumonia was clinically documented in 47 patients (36%). The IRR for lung consolidation was 0.55 (95% CI, 0.40-0.70) for LUS and 0.36 (95% CI, 0.21-0.51) for CXR. The sensitivity for detecting consolidation, interstitial disease, and pleural effusion was statistically similar for LUS and CXR compared with CT; however, specificity was higher for CXR. The negative predictive value was similar for CXR and LUS.

CONCLUSIONS

LUS has a sufficiently high IRR for detection of consolidation. Compared with CT, LUS and CXR have similar sensitivity, but CXR is more specific for findings indicating pneumonia.

Approach to Pediatric Chest Radiograph

Chest radiograph remains the first line imaging modality even today, especially in ICU settings. Hence proper interpretation of chest radiographs is crucial, which can be achieved by adopting a systematic approach and proper description and identification of abnormalities. In this review, the authors describe a short and comprehensive way of interpreting the pediatric chest radiograph.

First-line diagnosis of paediatric pneumonia in emergency: lung ultrasound (LUS) in addition to chest-X-ray (CXR) and its role in follow-up

OBJECTIVE

The role of lung ultrasound (LUS) integrated with chest X-ray (CXR) for the first-line diagnosis of paediatric pneumonia; to define its role during the follow-up to exclude complications.

METHODS

We performed a retrospective review of a cohort including 84 consecutive children (age range: 3-16 years; mean age: 6 years; 44 males, 40 females) with clinical signs of cough and fever. All the patients underwent CXR at admission integrated with LUS. Those positive at LUS were followed up with LUS until the complete resolution of the disease.

RESULTS

CXR showed 47/84 pneumonic findings. LUS showed 60/84 pneumonic findings; 34/60 pneumonic findings had a typical pattern of lung consolidation; 26/60 pneumonic findings showed association of multiple B-lines, findings consistent with interstitial involvement, and small and hidden consolidations not achievable by CXR. One case was negative at LUS because of retroscapular location. 60 patients were followed up with LUS; 28/60 patients showed a complete regression of the disease; 23/60 patients had a significant decrease in size of consolidation; 9/60 patients showed disease stability or insignificant decrease in size, thus requiring adjunctive LUS examinations.

CONCLUSION

LUS, integrated with CXR, revealed to be an accurate first-line technique to identify small pneumonic consolidations, especially for "CXR-occult" findings, and for early diagnosis of pleural effusion; furthermore, LUS follow-up allows complications to be verified and additional radiation exposures to be avoided.

ADVANCES IN KNOWLEDGE

The effective role of LUS in the diagnosis and follow-up of lung consolidations and pleural effusions in paediatric patients in an emergency setting.

A Survey of Pediatric CT Protocols and Radiation Doses in South Korean Hospitals to Optimize the Radiation Dose for Pediatric CT Scanning

Children are at greater risk of radiation exposure than adults because the rapidly dividing cells of children tend to be more radiosensitive and they have a longer expected life time in which to develop potential radiation injury. Some studies have surveyed computed tomography (CT) radiation doses and several studies have established diagnostic reference levels according to patient age or body size; however, no survey of CT radiation doses with a large number of patients has yet been carried out in South Korea. The aim of the present study was to investigate the radiation dose in pediatric CT examinations performed throughout South Korea. From 512 CT (222 brain CT, 105 chest CT, and 185 abdominopelvic CT) scans that were referred to our tertiary hospital, a dose report sheet was available for retrospective analysis of CT scan protocols and dose, including the volumetric CT dose index (CTDIvol), dose-length product (DLP), effective dose, and size-specific dose estimates (SSDE). At 55.2%, multiphase CT was the most frequently performed protocol for abdominopelvic CT. Tube current modulation was applied most often in abdominopelvic CT and chest CT, accounting for 70.1% and 62.7%, respectively. Regarding the CT dose, the interquartile ranges of the CTDIvol were 11.1 to 22.5 (newborns), 16.6 to 39.1 (≤1 year), 14.6 to 41.7 (2-5 years), 23.5 to 44.1 (6-10 years), and 31.4 to 55.3 (≤15 years) for brain CT; 1.3 to 5.7 (≤1 year), 3.9 to 6.8 (2-5 years), 3.9 to 9.3 (6-10 years), and 7.7 to 13.8 (≤15 years) for chest CT; and 4.0 to 7.5 (≤1 year), 4.2 to 8.9 (2-5 years), 5.7 to 12.4 (6-10 years), and 7.6 to 16.6 (≤15 years) for abdominopelvic CT. The SSDE and CTDIvol were well correlated for patients <5 years old, whereas the CTDIvol was lower in patients ≥6 years old. Our study describes the various parameters and dosimetry metrics of pediatric CT in South Korea. The CTDIvol, DLP, and effective dose were generally lower than in German and UK surveys, except in certain age groups.

The risk of cumulative radiation exposure in chest imaging and the advantage of bedside ultrasound

The increasing use and complexity of imaging techniques have not been matched by increasing awareness and knowledge by prescribers and practitioners. Imaging examinations that expose to ionizing radiation provide immense benefits when appropriate, yet they may result in an increased incidence of radiation-induced cancer in the long-term. The radiation issue is relevant not only for the individual patient but also for the community because small individual risks multiplied by millions of examinations become a significant population risk. As recently highlighted by recent European and American Guidelines, the long-term risk associated with radiation exposure should be considered in the risk-benefit assessment behind appropriate prescription of diagnostic testing.

Usefulness of lung ultrasound in the diagnosis of community-acquired pneumonia in children

BACKGROUND

Pneumonia is a life-threatening disease in children. With the current lack of universal diagnostic criteria, the diagnosis is usually made on clinical manifestations and findings from chest radiographs. Ultrasonography has recently been applied to the detection of pulmonary diseases. However, few data have been published showing its effectiveness in detecting pneumonia in children. The objective of this study was to determine the power of lung ultrasonography (LUS) for the diagnosis of pneumonia in children.

METHODS

This retrospective study was carried out by reviewing medical records. Patients admitted to a pediatric ward with a diagnosis of pneumonia from June 1, 2010 to December 31, 2012 were enrolled in this study. Personal information, laboratory data, characteristics on LUS scan, and the results of chest radiography and LUS were collected. We compared the detection rate of pneumonia by chest radiography and LUS. LUS scans were followed up in 23 patients during the progression of their disease.

RESULTS

A total of 163 patients was enrolled. Chest radiography was able to detect pneumonia in 152 patients, whereas LUS detected pneumonia in 159 patients. In LUS, the positive rates of the comet-tail sign, air bronchograms, fluid bronchograms, vascular pattern within the consolidation, and pleural effusion were 50.9%, 93.7%, 20.1%, and 28.9%, respectively. During follow up, the average size of the pneumonia patch in 23 patients decreased from 10.9 ± 8.7 cm(2) to 5.5 ± 8.2 cm(2), and finally to 2 ± 1.9 cm(2) on Day 1, Days 3-5 and Days 7-14, respectively.

CONCLUSION

LUS is a sensitive diagnostic tool with which to identify pneumonia in children. It is also useful in following up the progress of pneumonia. We suggest that LUS is a complementary tool to chest radiography in the diagnosis of pneumonia in children and that the follow up of pneumonia by LUS can reduce the exposure of children to ionizing radiation.

Pediatric chest CT at 70 kVp: a feasibility study in 129 children

BACKGROUND

Before introducing 70-kVp settings in the low-kilovoltage strategies for pediatric examinations, it was mandatory to demonstrate, at similar dose levels, an equivalence of image quality at 70 kVp and 80 kVp.

OBJECTIVE

To assess image quality of chest CT examinations acquired at 70 kVp in comparison with standard scanning at 80 kVp.

MATERIALS AND METHODS

We prospectively evaluated 129 children with a 70-kVp scanning protocol (group 1). All scanning parameters were kept similar to those usually selected for pediatric standard 80-kVp protocols, except the milliamperage increased by a factor of 1.6 to maintain comparable radiation dose. Image quality of group 1 examinations was compared to that of a paired population scanned at 80 kVp (group 2). The noninferiority hypothesis was fixed at 10% of the mean level of image noise.

RESULTS

There was no significant difference in the mean dose length product (DLP) and the volume computed tomography dose index (CTDIvol) between the groups (DLP: 20.5 ± 5.8 mGy.cm [group 1] vs. 19.7 ± 7.6 mGy.cm [group 2]; P = 0.06) (CTDIvol: 0.8 ± 0.1 mGy [group 1] vs. 0.8 ± 0.18 mGy [group 2]; P = 0.94). The mean of differences in image noise between group 1 and group 2 examinations was -1.38 (-2.59; -0.18), verifying the noninferiority hypothesis. Subjective image quality did not significantly differ between group 1 and group 2 examinations (P = 0.18).

CONCLUSION

At equivalent radiation dose levels, 70-kVp protocols provide similar image quality to that achievable at 80 kVp.

Cumulative radiation exposure and cancer risk estimation in children with heart disease

BACKGROUND

Children with heart disease are frequently exposed to imaging examinations that use ionizing radiation. Although radiation exposure is potentially carcinogenic, there are limited data on cumulative exposure and the associated cancer risk. We evaluated the cumulative effective dose of radiation from all radiation examinations to estimate the lifetime attributable risk of cancer in children with heart disease.

METHODS AND RESULTS

Children ≤6 years of age who had previously undergone 1 of 7 primary surgical procedures for heart disease at a single institution between 2005 and 2010 were eligible for the study. Exposure to radiation-producing examinations was tabulated, and cumulative effective dose was calculated in millisieverts. These data were used to estimate lifetime attributable risk of cancer above baseline using the approach of the Committee on Biological Effects of Ionizing Radiation VII. The cohort included 337 children exposed to 13 932 radiation examinations. Conventional radiographs represented 92% of examinations, whereas cardiac catheterization and computed tomography accounted for 81% of cumulative exposure. Overall median cumulative effective dose was 2.7 mSv (range, 0.1-76.9 mSv), and the associated lifetime attributable risk of cancer was 0.07% (range, 0.001%-6.5%). Median lifetime attributable risk of cancer ranged widely depending on surgical complexity (0.006%-1.6% for the 7 surgical cohorts) and was twice as high in females per unit exposure (0.04% versus 0.02% per 1-mSv effective dose for females versus males, respectively; P<0.001).

CONCLUSIONS

Overall radiation exposures in children with heart disease are relatively low; however, select cohorts receive significant exposure. Cancer risk estimation highlights the need to limit radiation dose, particularly for high-exposure modalities.

Clinical and immunological correlates of chest X-ray abnormalities in HIV-infected South African children with limited access to anti-retroviral therapy

BACKGROUND

The chest X-ray (CXR) abnormalities of human immunodeficiency virus (HIV)-infected children in low/middle income countries (LMIC's) have not been well studied.

OBJECTIVE

To describe the CXR abnormalities and associated clinical/immunological features in HIV-infected South African children.

MATERIALS AND METHODS

A prospective study of HIV-infected children who underwent baseline chest radiography and clinical and immunological HIV-staging. CXR abnormalities were stratified as grade 1 (mild) or grade 2 (moderate/severe). Univariate and multiple logistic regression analyses assessed associations between radiological severity and clinical/immunological parameters.

RESULTS

Three hundred thirty children (53% male), median age 23.8 months, were included; 303 (92%) had moderate/severe clinical disease and 225 (68%) moderate/severe immune suppression; 52 (16%) had a normal CXR; 169 (51%) had grade 2 CXR abnormalities, manifesting as: confluent opacification (n = 91, 28%), nodules (n = 37, 11%), or nodules with opacification (n = 41, 12%) Grade 2 abnormality was associated with more advanced clinical HIV disease (OR: 6.9; 95% CI: 1.9-25.6), CD4+ less than 20% (OR: 1.8; 95% CI: 1.0-3.0) and age over 24 months (OR: 4.1; 95% CI: 2.1-8.0).

CONCLUSION

CXR abnormalities are common in HIV-infected children in LMIC's. The extent of radiological abnormality correlates with age and clinical and immunological severity of HIV-disease.

Characterization of radiation exposure in early-onset scoliosis patients treated with the vertical expandable prosthetic titanium rib

BACKGROUND

The evaluation and treatment of patients with early-onset scoliosis requires multiple imaging studies and involves potential exposure to high cumulative lifetime doses of ionizing radiation. The Vertical Expandable Prosthetic Titanium Rib (VEPTR) used in the treatment of early-onset scoliosis requires numerous lengthening procedures and frequent radiographic follow-up. The purpose of this study was to quantify the ionizing radiation exposure in pediatric patients undergoing VEPTR treatment and to identify factors that place patients with early-onset scoliosis at greater risk of radiation exposure.

METHODS

Data were collected by retrospective review of the records of all patients with early-onset scoliosis who were treated with a VEPTR over a 4-year period (2007 to 2010). Diagnostic radiographs, computed tomography, intraoperative fluoroscopy, and nuclear medicine studies were identified and analyzed for ionizing radiation exposure. Total radiation exposure was determined and compared for risk factors such as etiology (eg, neuromuscular or congenital) and surgeon experience. In addition, radiographic studies directly related and unrelated to scoliosis treatment were compared.

RESULTS

Twenty-four patients had 121 surgical procedures (mean 5.0/patients) and 962 imaging studies (mean 40/patients). The mean estimated cumulative radiation dose per patient during follow-up was 86.7 mSv (range, 42.6 to 174.9 mSv) with a mean dose per year of 34 mSv (range, 22.9 to 47.1 mSv). Patients with congenital scoliosis received greater mean amounts of radiation (35.2 mSv) than patients with neuromuscular scoliosis (31.9 mSv). Patients treated within the first 2 years of the study period had higher radiation exposure (42.4 mSv) compared with patients treated in the last 2 years (24.9 mSv) (P<0.001).

CONCLUSIONS

Ionizing radiation is an inevitable side effect of the VEPTR treatment for early-onset scoliosis. There are differences in the amount and sources of radiation exposure between patients with early-onset scoliosis secondary to congenital and neuromuscular causes. Surgeon experience is correlated with decreased levels of radiation exposure. Awareness of the potential for high levels of radiation exposure, as well as patient and surgeon-related factors involved, may lead to more effective radiation-reduction strategies.

LEVEL OF EVIDENCE

Level IV--retrospective case study.