Medical radiation exposure in children with inflammatory bowel disease estimates high cumulative doses

BACKGROUND

Children with inflammatory bowel disease (IBD) undergo imaging using ionizing radiation and may be exposed to high cumulative radiation. We hypothesized that children with IBD have high exposure to radiation from medical imaging.

METHODS

An Institutional Review Board (IRB)-approved retrospective chart review from 2002-2008 was performed on all patients with IBD. Radiographic studies performed were recorded and exposure for each study was estimated.

RESULTS

A total of 117 children with IBD (86 Crohn's disease [CD], 31 ulcerative colitis [UC]) were evaluated. The median current exposure was 15.1 mSv in CD and 7.2 mSv in UC (P = 0.005). Computed tomography (CT) scan and small bowel follow-through (SBFT) were responsible for 43% and 36% of all radiation exposures, respectively. The rate of radiation was higher in CD compared to UC (4.3 versus 2.2 mSv/yr). In CD, the rate of exposure was highest in the first 3 years of diagnosis (8.2 mSv/yr), and no different between the 3-5 year follow-up and 5+ year follow-up groups (3.8 versus 4.3 mSv/yr). Using the annual dose rate in those followed for more than 3 years, an estimated 47 out of 78 (60%) children (40 CD, 7 UC) would exceed 50 mSv by 35 years of age.

CONCLUSIONS

Radiation exposure from medical imaging is high in a subset of children diagnosed with IBD. Estimation of radiation exposure at age 35 suggests a significant portion of children with IBD will have high radiation exposure in their lifetime. Nonionizing imaging such as magnetic resonance imaging (MRI) and ultrasound should be offered to children with IBD as an alternative to current imaging that employs radiation.

Quantitative assessment of chronic lung disease of infancy using computed tomography

The aims of this study were to determine whether infants and toddlers with chronic lung disease of infancy (CLDI) have smaller airways and lower lung density compared with full-term healthy controls. Multi-slice computed tomography (CT) chest scans were obtained at elevated lung volumes during a brief respiratory pause in sedated infants and toddlers; 38 CLDI were compared with 39 full-term controls. For CLDI subjects, gestational age at birth ranged from 25 to 29 weeks. Airway size was measured for the trachea and the next three to four generations into the right lower lobe; lung volumes and tissue density were also measured. The relationship between airway size and airway generation differed between the CLDI and full-term groups; the sizes of the first and second airway generations were larger in the shorter CLDI than in the shorter full-term subjects. The increased size in the airways in the CLDI subjects was associated with increasing mechanical ventilation time in the neonatal period. CLDI subjects had a greater heterogeneity of lung density compared with full-term subjects. Our results indicate that quantitative analysis of multi-slice CT scans at elevated volumes provides important insights into the pulmonary pathology of infants and toddlers with CLDI.

Approaches to promotion and implementation of action on Radiation Protection for children

The Radiation Protection in Medicine conference, reviewed in this journal supplement, outlined nine strategies to promote radiation protection for patients. The Alliance for Radiation Safety in Pediatric Imaging has focused its work on three of those areas: creating awareness of the need and opportunities for radiation protection for children; developing open-source educational materials for medical professionals and parents on this critical topic for improved patient safety and communication; and lastly, advocating on behalf of children with industry, government and regulatory bodies to improve equipment design and safety features, standardisation of nomenclature and displays of dose reports across vendor platforms that reflect the special considerations of children.

Image Gently: progress and challenges in CT education and advocacy

Significant progress has been made in radiation protection for children during the last 10 years. This includes increased awareness of the need for radiation protection for pediatric patients with international partnerships through the Alliance for Radiation Safety in Pediatric Imaging. This paper identifies five areas of significant progress in radiation safety for children: the growth of the Alliance; the development of an adult radiation protection campaign Image Wisely™; increased collaboration with government agencies, societies and the vendor community; the development of national guidelines in pediatric nuclear medicine, and the development of a size-based patient dose correction factor by the American Association of Physicists in Medicine, Task Group 204. However, many challenges remain. These include the need for continued education and change of practice at adult-focused hospitals where many pediatric CT exams are performed; the need for increased emphasis on appropriateness of pediatric imaging and outcomes research to validate the performance of CT studies, and the advancement of the work of the first pediatric national dose registry to determine the "state of the practice" with the final goal of establishing ranges of optimal CT technique for specific scan indications when imaging children with CT.

Use of medical imaging procedures with ionizing radiation in children: a population-based study

OBJECTIVE

To determine population-based rates of the use of diagnostic imaging procedures with ionizing radiation in children, stratified by age and sex.

DESIGN

Retrospective cohort analysis.

SETTING

All settings using imaging procedures with ionizing radiation.

PATIENTS

Individuals younger than 18 years, alive, and continuously enrolled in UnitedHealthcare between January 1, 2005, and December 31, 2007, in 5 large US health care markets.

MAIN OUTCOME MEASURES

Number and type of diagnostic imaging procedures using ionizing radiation in children.

RESULTS

A total of 355 088 children were identified; 436 711 imaging procedures using ionizing radiation were performed in 150 930 patients (42.5%). The highest rates of use were in children older than 10 years, with frequent use in infants younger than 2 years as well. Plain radiography accounted for 84.7% of imaging procedures performed. Computed tomographic scans-associated with substantially higher doses of radiation-were commonly used, accounting for 11.9% of all procedures during the study period. Overall, 7.9% of children received at least 1 computed tomographic scan and 3.5% received 2 or more, with computed tomographic scans of the head being the most frequent.

CONCLUSIONS

Exposure to ionizing radiation from medical diagnostic imaging procedures may occur frequently among children. Efforts to optimize and ensure appropriate use of these procedures in the pediatric population should be encouraged.

Lung growth in infants and toddlers assessed by multi-slice computed tomography

RATIONALE AND OBJECTIVES

Postnatal lung growth and development have primarily been evaluated from a very limited number of autopsied lungs, but it remains unclear whether alveolarization of the lung is complete during infancy and whether the conducting airways grow proportionately. The purpose of this study was to evaluate lung growth and development in vivo in infants and toddlers using multislice computed tomography.

MATERIALS AND METHODS

Thirty-eight subjects (14 male, 24 female) aged 17 to 142 weeks underwent low-dose volumetric high-resolution computed tomographic imaging at an inflation pressure of 20 cm H(2)O during an induced respiratory pause. Lung volume and weight were determined, as well as airway dimensions (inner and outer area and wall area) for the trachea and the next three to four generations.

RESULTS

Lung volume, air volume, and tissue volume increased linearly with body length. The air and tissue components of the lung parenchyma increased at a constant rate with each other. In addition, airway caliber decreased with increasing generation from the trachea into each lobe. Airway caliber was also correlated with body length; however, there was no interaction effect between airway generation and body length on transformed airway size.

CONCLUSIONS

In vivo assessment suggests that the growth of the lung parenchyma in infants and toddlers occurred with a constant relationship between air volume and lung tissue, which is consistent with lung growth occurring primarily by the addition of alveoli rather than the expansion of alveoli. In addition, the central conducting airways grow proportionately in infants and toddlers. This information may be important for evaluating subjects with arrested lung development.

Image Gently: providing practical educational tools and advocacy to accelerate radiation protection for children worldwide

The Alliance for Radiation Safety in Pediatric Imaging is an organization of over 45 international professional societies and agencies with the goal of promoting radiation safety for children. The Alliance, through the Image Gently campaign, uses social marketing techniques and critical partnerships with vendors, government agencies, and not-for-profit organizations, to advocate best practices in radiation use and safety. Advocacies include improving education regarding radiation risk to patients from medical imaging for radiologists, technologists, and referring physicians; promoting standardization of dose measurements and display across vendor equipment; and improving medical literacy for parents.

Imaging of Chest Infections in Children

■ Imaging studies have limited value in the differentiation between viral and bacterial lower respiratory tract infections (moderate evidence).

■ CT provides more information than plain radiographs for complicated pulmonary infections with empyema, pleural effusion, or bronchopleural fistula (moderate evidence).

■ In immunocompromised patients, CT has been shown to characterize the type of infection better than plain radiographs (moderate evidence).

■ Ultrasound has an advantage over CT in the identification and characterization of complicated effusions (moderate evidence).

■ Early detection and therefore intervention for pleural complications of pneumonia are critical and can result in better outcomes (moderate evidence).

■ Early surgery (VATS) is more cost-effective than thoracotomy (without or with image guidance) in the treatment of empyemas in children (strong evidence).

Female medical students' interest in radiology careers

OBJECTIVE

Women are underrepresented in radiology. The aim of this study was to measure first-year medical students' level of interest in radiology and their attitudes toward factors that could affect residency specialty choices to further understand how to recruit women into radiology careers.

MATERIALS AND METHODS

First-year medical students were administered surveys before and after a 7-week required introductory radiology course. Students rated interest in radiology on a scale ranging from 0 to 10 (low to high). Ten factors that could affect residency choice ("competitive residency," "shorter residency," "role models," "more jobs," "above average income," "flexible work hours," "work is technological," "work is visual," "intellectual challenge," and "more patient contact") were each rated as negative, neutral, or positive. Correlations between level of interest in radiology and the 10 factors were analyzed using Spearman's coefficients.

RESULTS

The mean levels of interest in radiology were 4.5 for men and 4.0 for women (P = .38) among 116 precourse respondents and 5.2 for men and 4.3 for women (P = .11) among 80 postcourse respondents. The factors most frequently rated as having a positive impact on residency choice were "flexible work hours," "intellectual challenge," "role models," and "more patient contact." Compared with men, women less frequently rated "work is technological" (20% vs 43%; P = .0002) and "work is visual" (50% vs 72%; P = .03) as having a positive impact and more frequently rated "more patient contact" (89% vs 77%; P = .02) as having a positive impact. For women, the strongest correlation between level of interest in radiology and the 10 factors was for "role models" (correlation coefficient = .30, P = .03).

CONCLUSION

Interest in radiology did not differ by gender. Opportunities in radiology for flexible hours, intellectual challenge, patient care, and mentoring should be promoted early in medical education to female students to maintain and increase their interest in radiology.

Diagnostic performance of the upper gastrointestinal series in the evaluation of children with clinically suspected malrotation

BACKGROUND

Malrotation is a congenital disorder of abnormal intestinal rotation and fixation that predisposes infants to potentially life-threatening midgut volvulus. Upper gastrointestinal tract (UGI) examination is sometimes equivocal and can lead to inaccurate diagnosis.

OBJECTIVE

To determine the diagnostic performance of UGI examinations in children who subsequently underwent a Ladd procedure for suspected malrotation or volvulus.

MATERIALS AND METHODS

We reviewed all children up to 21 years old who had undergone both a UGI examination and a Ladd procedure for possible malrotation across 9 years. Children were excluded if they had not undergone either a UGI examination or a Ladd procedure and if congenital abdominal wall defects were present.

RESULTS

Of 229 patients identified, 166 (59% male, median age 67 days) were included. Excluded were 47 without a UGI series, 12 with omphalocele or gastroschisis, 1 without verifiable operative data, 1 who had not undergone a Ladd procedure, and 2 older than 21 years. Of the 166 patients, 40% were neonates and 73% were <12 months old, and 31% presented with bilious vomiting and 15% with abdominal distention. Of 163 patients with surgically verified malrotation, 156 had a positive UGI examination, a sensitivity of 96%. There were two patients with a false-positive UGI examination and seven with false-negative examination. Jejunal position was normal in six of the seven with a false-negative examination and abnormal in the two with a false-positive examination. Of 38 patients with surgically verified volvulus, 30 showed volvulus on the UGI series. Five required bowel resection and three died.

CONCLUSION

Jejunal position can lead to inaccurate UGI series interpretation. Meticulous technique and periodic assessment of performance will help more accurately diagnose difficult or equivocal cases.

MR cholangiopancreatography in children: feasibility, safety, and initial experience

BACKGROUND

The indications for MR cholangiopancreatography (MRCP) in children, and its safety and findings, might differ from those in adults and are not well described.

OBJECTIVE

To investigate the safety, feasibility, and accuracy of MRCP in children.

MATERIALS AND METHODS

We reviewed all prospective MRCP reports, noting the indication, the use of secretin, endoscopic retrograde cholangiopancreatography (ERCP) findings, and patient outcomes. Two readers reviewed each MRCP study by consensus to rate duct visualization and compare pancreatic duct sizes before and after secretin administration (paired t-test). The likelihood of a normal versus an abnormal MRCP study was compared by gender, pancreatitis as the primary indication, secretin use, and whether ERCP was performed (Fisher's exact test), as well as age (t-test).

RESULTS

A total of 85 MRCP studies were performed in children (mean age 10.3 years), most commonly for evaluation of pancreatitis (n=47, 55%); 41 (48%) used secretin and 39 (46%) used a negative oral contrast agent. Of the 85 studies, 72 (85%) had excellent image quality and 43 were normal. ERCP was performed after 16 of the 85 MRCP studies (19%); the diagnoses were concordant with those of MRCP in 13 (81%). There were 42 abnormal MRCP studies, and these were more likely to be in girls (P=0.03) and in children who had undergone ERCP (P<0.01). Secretin and the negative oral contrast agent were well-tolerated. Secretin improved duct visualization (P<0.001).

CONCLUSION

MRCP safely and accurately depicted pancreaticobiliary anatomy in children. The use of secretin improved visualization of the pancreatic duct.

Learning radiology a survey investigating radiology resident use of textbooks, journals, and the internet

RATIONALE AND OBJECTIVES

We surveyed radiology residents to understand which information sources residents use to learn radiology.

MATERIALS AND METHODS

A 15-question survey on learning resources was given to radiology residents at one institution. The survey queried residents about their preferences for sources when encountering a question in the reading room and when attempting to learn radiology and about the frequency with which they read radiology/medical journals. Residents ranked Internet sites for these learning purposes. The IRB gave administrative approval for the survey.

RESULTS

All residents (60 of 60) completed the survey. When a question is encountered in the reading room, 50 of 60 (83%) respondents prefer to use the Internet as a first-line resource, and 15% prefer a textbook. When using the Internet, 46 of 60 (77%) residents use Google as their first source, 12% use eMedicine, 3% use StatDx, 3% use UpToDate, and 2% use RSNA online journals. eMedicine was the most popular second resource at 65%. Of 60, 59 (98%) residents prefer to use physician/scientist professional Web sites (e.g., eMedicine) rather than consumer/patient-oriented Web sites. When using the Internet to learn radiology, 32% of residents prefer AuntMinnie, 30% use Edactic.com, 22% use ACR Case-In-Point, 3% use www.learningradiology.com, 2% use radquiz.com, and 2% use RadioGraphics online. On average, residents listed 6.2 Internet sites. For textbook learning, 58% of residents prefer case review or requisite books, while 32% prefer traditional textbooks. The mean number of textbooks owned is 5.3, while the mean number of case review or requisite books is 5.4. Of 60 residents, 8 own most or all the case review and requisite books. Twenty-eight percent of residents read radiology textbooks daily; 45%, weekly; 8%, monthly; and 15%, occasionally. Twenty-three percent of residents read radiology journals monthly; 15%, quarterly; 37%, occasionally; and 23%, never. Five percent of residents read medical journals (e.g., The New England Journal of Medicine) monthly; 2%, quarterly; 48%, occasionally; and 45%, never.

CONCLUSION

Currently, residents prefer the Internet when researching a question, with Google as the Web site most commonly used. Case review or requisite books are more commonly used than are traditional textbooks. Radiology resident learning has rapidly shifted from traditional textbooks and journals to the Internet and short case review books.

The inappropriate use of imaging studies: a report of the 2004 Intersociety Conference

The participants of the 2004 Intersociety Conference met to discuss the growing problem of self-referral. The United States spends more of its gross national product on health care than other countries, especially Japan and those in Western Europe. Imaging accounts for a large and growing portion of those costs. Despite spending so much on health care, the United States ranks relatively low in measures of national health, including such parameters as infant mortality and even life expectancy. Because the federal government must keep health care expenditures to a "sustainable growth rate," increases in use are likely to be accompanied by decreases in reimbursement per case. Thus, conference participants agreed that the real problem is inappropriate use, which may arise from (1) ignorance of what specific imaging studies are needed when, (2) high public expectations for imaging tests, (3) the fear of liability for a missed diagnosis (defensive medicine), and (4) self-referral. The Stark laws have been largely ineffective in preventing self-referral because there are many loopholes, and the laws are inconsistently enforced. Among the many potential solutions are the education of our clinical colleagues on appropriateness criteria; the education of the public on the costs of inappropriate use; tort reform; and working with third-party payers, especially the private insurance industry, to develop vigorous privileging programs, to require precertification for self-referred studies, or to establish differential payments for self-referred and non-self-referred imaging.