Jonathan O. Swanson

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.

First look: a cluster-randomized trial of ultrasound to improve pregnancy outcomes in low income country settings

BackgroundIn high-resource settings, obstetric ultrasound is a standard component of prenatal care used to identify pregnancy complications and to establish an accurate gestational age in order to improve obstetric care. Whether or not ultrasound use will improve care and ultimately pregnancy outcomes in low-resource settings is unknown.Methods/DesignThis multi-country cluster randomized trial will assess the impact of antenatal ultrasound screening performed by health care staff on a composite outcome consisting of maternal mortality and maternal near-miss, stillbirth and neonatal mortality in low-resource community settings. The trial will utilize an existing research infrastructure, the Global Network for Women’s and Children’s Health Research with sites in Pakistan, Kenya, Zambia, Democratic Republic of Congo and Guatemala. A maternal and newborn health registry in defined geographic areas which documents all pregnancies and their outcomes to 6 weeks post-delivery will provide population-based rates of maternal mortality and morbidity, stillbirth, neonatal mortality and morbidity, and health care utilization for study clusters. A total of 58 study clusters each with a health center and about 500 births per year will be randomized (29 intervention and 29 control). The intervention includes training of health workers (e.g., nurses, midwives, clinical officers) to perform ultrasound examinations during antenatal care, generally at 18–22 and at 32–36 weeks for each subject. Women who are identified as having a complication of pregnancy will be referred to a hospital for appropriate care. Finally, the intervention includes community sensitization activities to inform women and their families of the availability of ultrasound at the antenatal care clinic and training in emergency obstetric and neonatal care at referral facilities.DiscussionIn summary, our trial will evaluate whether introduction of ultrasound during antenatal care improves pregnancy outcomes in rural, low-resource settings. The intervention includes training for ultrasound-naïve providers in basic obstetric ultrasonography and then enabling these trainees to use ultrasound to screen for pregnancy complications in primary antenatal care clinics and to refer appropriately.Trial registrationClinicaltrials.gov (NCT # 01990625)

The diagnostic impact of limited, screening obstetric ultrasound when performed by midwives in rural Uganda

Objective:To evaluate the diagnostic impact of limited obstetric ultrasound (US) in identifying high-risk pregnancies when used as a screening tool by midwives in rural Uganda.Study Design:This was an institutional review board-approved prospective study of expecting mothers in rural Uganda who underwent clinical and US exams as part of their standard antenatal care visit in a local health center in the Isingiro district of Uganda. The midwives documented clinical impressions before performing a limited obstetric US on the same patient. The clinical findings were then compared with the subsequent US findings to determine the diagnostic impact. The midwives were US-naive before participating in the 6-week training course for limited obstetric US.Result:Midwife-performed screening obstetric US altered the clinical diagnosis in up to 12% clinical encounters. This diagnostic impact is less (6.7 to 7.4%) if the early third trimester diagnosis of malpresentation is excluded. The quality assurance review of midwives’ imaging demonstrated 100% sensitivity and specificity in the diagnosing gestational number, and 90% sensitivity and 96% specificity in the diagnosis of fetal presentation.Conclusion:Limited, screening obstetric US performed by midwives with focused, obstetric US training demonstrates the diagnostic impact for identifying conditions associated with high-risk pregnancies in 6.7 to 12% of patients screened. The limited obstetric US improved diagnosis of early pregnancy complication as well as later gestation twins and malpresentation. Midwives who have undergone focused 6-week limited obstetric US training proved capable of diagnosing twins and fetal presentation with high sensitivity and specificity.

Iatrogenic radiation exposure to patients with early onset spine and chest wall deformities.

Study Design. Retrospective cohort series. Objective. Characterize average iatrogenic radiation dose to a cohort of children with thoracic insufficiency syndrome (TIS) during assessment and treatment at a single center with vertically expandable prosthetic titanium rib. Summary of Background Data. Children with TIS undergo extensive evaluations to characterize their deformity. No standardized radiographical evaluation exists, but all reports use extensive imaging. The source and level of radiation these patients receive is not currently known. Methods. We evaluated a retrospective consecutive cohort of 62 children who had surgical treatment of TIS at our center from 2001–2011. Typical care included obtaining serial radiographs, spine and chest computed tomographic (CT) scans, ventilation/perfusion scans, and magnetic resonance images. Epochs of treatment were divided into time of initial evaluation to the end of initial vertically expandable prosthetic titanium rib implantation with each subsequent epoch delineated by the next surgical intervention. The effective dose for each examination was estimated within millisieverts (mSv). Plain radiographs were calculated from references. Effective dose was directly estimated for CT scans since 2007 and an average of effective dose from 2007–2011 was used for scans before 2007. Effective dose from fluoroscopy was directly estimated. All doses were reported in mSv. Results. A cohort of 62 children had a total of 447 procedures. There were a total of 290 CT scans, 4293 radiographs, 147 magnetic resonance images, and 134 ventilation/perfusion scans. The average accumulated effective dose was 59.6 mSv for children who had completed all treatment, 13.0 mSv up to initial surgery, and 3.2 mSv for each subsequent epoch of treatment. CT scans accounted for 74% of total radiation dose. Conclusion. Children managed for TIS using a consistent protocol received iatrogenic radiation doses that were on average 4 times the estimated average US background radiation exposure of 3 mSv/yr. CT scans comprised 74% of the total dose. Level of Evidence: 3

Safety essentials: acute reactions to iodinated contrast media.

The objectives of this article are to review the diagnosis and management of acute nonrenal reactions to iodinated contrast media. We will begin by discussing the types of contrast media and their correlative rates of reaction. The mechanism of contrast reactions, predisposing risk factors, and preventative measures will then be discussed. The remainder of the article will review the assessment of potential reactions, initial management, and treatment algorithms for specific reactions.

Screening obstetric ultrasound training for a 5-country cluster randomized controlled trial.

Abstract With decreased equipment cost, provision of ultrasound is now feasible in some low resource settings. Screening obstetric ultrasound may identify potential pregnancy complications and, with this knowledge, allow women to plan to deliver at the appropriate level of care. In this article, we describe a 10-day course with quality assurance activities to train ultrasound-naïve, nonphysician healthcare professionals at midlevel health facilities to perform screening obstetric ultrasound. Those trained will participate in a cluster randomized controlled trial to assess the impact of screening obstetric ultrasound on maternal and newborn outcomes.

Upper thoracic shape in children with pectus excavatum: Impact on lung function

Pectus excavatum (PE) can present with respiratory complaints in childhood. However severity of the PE, measured by the Pectus Severity Index (PSI), correlates only modestly with reduced vital capacity (VC). We hypothesized that another upper thoracic feature, a pectus gracilis (PG) or slender chest, co‐exists with PE, and impacts lung function.

Web-Based Quality Assurance Process Drives Improvements in Obstetric Ultrasound in 5 Low- and Middle-Income Countries

Newly trained sonographers improved performance through a quality assurance process that merged (1) evaluation by remote experts of images uploaded to a website, with (2) periodic in-person skill tests. To promote sustainability, in-country supervisors gradually assumed more responsibility for image evaluation. The user-friendly and efficient interface used simple menus and forms, customized based on the users role. Newly trained sonographers improved performance through a quality assurance process that merged (1) evaluation by remote experts of images uploaded to a website, with (2) periodic in-person skill tests. To promote sustainability, in-country supervisors gradually assumed more responsibility for image evaluation. The user-friendly and efficient interface used simple menus and forms, customized based on the users role. ABSTRACT High quality is important in medical imaging, yet in many geographic areas, highly skilled sonographers are in short supply. Advances in Internet capacity along with the development of reliable portable ultrasounds have created an opportunity to provide centralized remote quality assurance (QA) for ultrasound exams performed at rural sites worldwide. We sought to harness these advances by developing a web-based tool to facilitate QA activities for newly trained sonographers who were taking part in a cluster randomized trial investigating the role of limited obstetric ultrasound to improve pregnancy outcomes in 5 low- and middle-income countries. We were challenged by connectivity issues, by country-specific needs for website usability, and by the overall need for a high-throughput system. After systematically addressing these needs, the resulting QA website helped drive ultrasound quality improvement across all 5 countries. It now offers the potential for adoption by future ultrasound- or imaging-based global health initiatives.

Impact of Introducing Routine Antenatal Ultrasound Services on Reproductive Health Indicators in Mpigi District, Central Uganda.

Abstract The preponderance of global maternal and neonatal deaths occurs in low-resource countries. The risk factors that lead to these deaths are often detectable with ultrasound (US) and potentially preventable. We assessed the impact of performing US scanning during antenatal care (ANC) on reproductive health service utilization in a rural Ugandan district. This pragmatic comparative study was conducted in 2 constituencies of Mpigi district in Uganda. In the 5 intervention sites located in the Mawokota North constituency, facility midwives were trained in limited obstetric US scanning. They were equipped with solar-powered portable US machines and redeployed to offer US scanning as an integral component of ANC. The 5 control sites in the Mawokota South constituency offered the same ANC services without US scanning. We compared the difference in the first and fourth ANC attendance, facility deliveries, and referral of obstetric complications in the intervention and the control sites before and after the introduction of US. There was a 32% increase in the first ANC attendance at the intervention sites compared with 7.4% in the controls sites (P < 0.001). In the intervention sites, the fourth antenatal attendance increased by 147% compared with 0.6% decline in the control sites (P < 0.001). Referrals of high-risk pregnancies increased by 40.7% in the intervention sites compared with 25% in the control site. The number of births at the interventional sites increased by 34.1% compared with 29.5% in the control sites. Integration of limited obstetric US into routine ANC visits is associated with an increase in ANC attendance.

Challenges of implementing antenatal ultrasound screening in a rural study site: A case study From the Democratic Republic of the Congo

In the context of a well-resourced research project on obstetric ultrasound, we encountered major challenges, including security and maintenance of the equipment, electricity requirements, health systems integration, and a variety of other systems issues. We propose future ultrasound interventions have at minimum a functioning health system with skilled and motivated staff, access to a referral hospital capable of providing affordable and higher levels of care, and feasible transportation means. In the context of a well-resourced research project on obstetric ultrasound, we encountered major challenges, including security and maintenance of the equipment, electricity requirements, health systems integration, and a variety of other systems issues. We propose future ultrasound interventions have at minimum a functioning health system with skilled and motivated staff, access to a referral hospital capable of providing affordable and higher levels of care, and feasible transportation means. Persistent global disparities in maternal and neonatal outcomes and the emergence of compact ultrasound technology as an increasingly viable technology for low-resource settings provided the genesis of the First Look Ultrasound study. Initiated in 2014 in 5 low- and middle-income countries and completed in June 2016, the studys intervention included the training of health personnel to perform antenatal ultrasound screening and to refer women identified with high-risk pregnancies to hospitals for appropriate care. This article examines the challenges that arose in implementing the study, with a particular focus on the site in Equateur Province of the Democratic Republic of the Congo (DRC) where the challenges were greatest and the efforts to meet these challenges most illuminating. During the study period, we determined that with resources and dedicated staff, it was possible to leverage the infrastructure and implement ultrasound at antenatal care across a variety of remote sites, including rural DRC. However, numerous technical and logistical challenges had to be addressed including security of the equipment, electricity requirements, and integration of the intervention into the health system. To address security concerns, in most of the countries field sonographers were hired and dispatched each day with the equipment to the health centers. At the end of each day, the equipment was locked in a secure, central location. To obtain the required power source, the DRC health centers installed solar panels bolted on adjacent poles since the thatch roofs of the centers prohibited secure roof-top installation. To realize the full value of the ultrasound intervention, women screened with high-risk pregnancies had to seek a higher level of care at the referral hospital for a definitive diagnosis and appropriate care. While the study did provide guidance on referral and systems management to health center and hospital administration, the extent to which this resulted in the necessary structural changes varied depending on the motivation of the stakeholders. In order for such an intervention to be scaled up and sustained as part of a health systems general services, it would require considerable effort, political will, and financial and human resources. Preliminary results from the study indicate that taking routine antenatal ultrasound screening to scale is not warranted. Lessons learned in implementing the study, however, can help inform future studies or programs that are considering use of ultrasound or other imaging technology for other applications in low-resource settings.