Nonoperative management of asymptomatic traumatic pulmonary hernia in a young child.
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Biomedical subjects
Publications and source records attributed to Donald P Frush.
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Evidence from numerous studies indicates that large numbers of patients are harmed by medical errors while receiving health-care services in the United States today. The 1999 Institute of Medicine report on medical errors recommended that hospitals and health-care agencies "establish safety programs to act as a catalyst for the development of a culture of safety" [1]. In this article, we describe one approach to successful implementation of a hospital-based patient safety program. Although our experience at Duke University Health System will be used as an example, the needs, principles, and solutions can apply to a variety of other health-care practices. Key components include the development of safety teams, provision of tools that teams can use to support an environment of safety, and ongoing program modification to meet patient and staff needs and respond to changing priorities. By moving patient safety to the forefront of all that we do as health-care providers, we can continue to improve our delivery of health care to children and adults alike. This improvement is fostered when we enhance the culture of safety, develop a constant awareness of the possibility of human and system errors in the delivery of care, and establish additional safeguards to intercept medical errors in order to prevent harm to patients.
Tremendous advances have been made in imaging in children with both congenital and acquired heart disease. These include technical advances in cardiac catheterization and conventional angiography, especially with advancements in interventional procedures, as well as noninvasive imaging with MR and CT angiography. With rapid advances in multidetector CT (MDCT) technology, most recently 64-detector array systems (64-slice MDCT), have come a number of advantages over MR. However, both conventional and CT angiography impart radiation dose to children. Although the presence of radiation exposure to children has long been recognized, it is apparent that our ability to assess this dose, particularly in light of the rapid advancements, has been limited. Traditional methods of dosimetry for both conventional and CT angiography are somewhat cumbersome or involve a potential for substantial uncertainty. Recent developments in dosimetry, including metal oxide semiconductor field effect transistors (MOSFET) and the availability of anthropomorphic, tissue-equivalent phantoms have provided new opportunities for dosimetric assessments. Recent work with this technology in state-of-the-art cardiac angiography suites as well as with MDCT have offered direct comparisons of doses in infants and children undergoing diagnostic cardiac evaluation. It is with these dose data that assessment of risks, and ultimately the assessment of risk-benefit, can be better achieved.
OBJECTIVE: The purpose of our study was to determine radiation dose to the fetus at early gestation when contemporary MDCT scanners are used for common clinical indications. MATERIALS AND METHODS: Anthropomorphic phantoms were constructed to reflect a pregnant woman. Thermoluminescence dosimeters (TLDs) and metal oxide semiconductor field effect transistor (MOSFET) detectors were placed in appropriate locations to determine real-time radiation exposure to the fetus at 0 and 3 months' gestation. Imaging was performed on a 16-MDCT scanner using current institutional CT protocols: renal stone (140 kVp, 160 mA, rotation time of 0.5 sec, 16 x 0.625 mm), appendix (140 kVp, 340 mA, rotation time of 0.5 sec, 16 x 0.625 mm), and pulmonary embolus (140 kVp, 380 mA, rotation time of 0.8 sec, 16 x 1.25 mm). RESULTS: The radiation dose to the fetus at 0 and 3 months, respectively, was as follows: renal stone protocol, 0.8-1.2 and 0.4-0.7 cGy; appendix protocol, 1.52-1.68 and 2-4 cGy; and pulmonary embolus protocol, 0.024-0.047 and 0.061-0.066 cGy. CONCLUSION: Radiation doses to the fetus from institutional MDCT protocols that may be used during pregnancy (for pulmonary embolus, appendicitis, and renal colic) are below the level thought to induce neurologic detriment to the fetus. Imaging the mother for appendicitis theoretically may double the fetal risk for developing a childhood cancer. Radiation doses to the fetus from pulmonary embolus chest CT angiography are of the same magnitude as ventilation-perfusion (V/Q) scanning.
OBJECTIVE: The objective of our study was to determine the radiation dose to the female breast from current 16-MDCT body examinations. MATERIALS AND METHODS: Metal oxide semiconductor field effect transistor (MOSFET) detectors were placed in four quadrants of the breast of a female-configured anthropomorphic phantom to determine radiation dose to the breast. Imaging was performed on a 16-MDCT scanner (LightSpeed, GE Healthcare) using current clinical protocols designed to assess pulmonary embolus (PE) (140 kVp, 380 mA, 0.8-sec rotation, 16 x 1.25 mm collimation), appendicitis (140 kVp, 340 mA, 0.5-sec rotation, 16 x 0.625 mm collimation), and renal calculus (140 kVp, 160 mA, 0.5-sec rotation, 16 x 0.625 mm collimation). RESULTS: Radiation dose to the breast ranged from 4 to 6 cGy for the PE protocol and up to 1-2 cGy in the inferior aspect of the right breast and lateral aspect of the left breast for the appendicitis protocol. The renal calculus protocol yielded less than 150 microGy absorbed breast dose. CONCLUSION: Current clinical chest and abdomen protocols result in vairable radiation doses to the breast. The magnitude of exposure may have implications for imaging strategies.
PURPOSE: To develop and validate a technique based on characteristics of real lesions for simulating realistic small liver lesions on pediatric computed tomographic (CT) images. MATERIALS AND METHODS: The institutional review board provided exempt status for this study, determined that it was not subject to HIPAA compliance, and did not require informed consent. Patient identification information was removed from clinical images from contrast material-enhanced multi-detector row CT examinations performed in 10 children. Patients were infants or children up to 18 years old. Information about sex was not available. Children had one or more liver lesions of 2-6 mm in maximum transverse diameter. Images with more than one lesion were rendered multiple times, and each time, all but one of the lesions were digitally removed in sequence. This process provided images (n = 19) with a single real lesion. For consistency, the same image backgrounds (images with all real lesions removed) were used to create an identical number of images (n = 19), each with a single simulated lesion. Subsequently, three radiologists independently assessed images of real and simulated lesions that were presented in random order with a score on a continuous scale of 0 (definitely simulated) to 100 (definitely real). Mixed-model analysis of variance was used to test the null hypothesis that the difference in population mean scores between the two lesion types was zero. RESULTS: The observer study did not reveal a significant difference in the ability of any radiologist to discriminate between real and simulated lesions (P > .31). The differences in mean scores for discrimination between real and simulated lesions for the three observers were -6, 9, and -7, respectively. The estimated overall difference was -1. CONCLUSION: Mathematic simulation of liver lesions is a feasible technique for creating realistic lesions for image quality or dose reduction studies in pediatric CT.
CT angiography is now an accepted application of contemporary multidetector row CT. Faster scanning, thinner slices, and improvement in intravenous contrast enhancement are benefits that have offered unique opportunities for pediatric thoracic angiographic evaluation, and often obviate routine angiography. Pediatric CT angiography can be challenging but adherence to a relatively straightforward step-by-step method, emphasizing patient preparation and technical familiarity, can result in excellent examinations even in the smallest infants and most complex clinical scenarios.
Computed tomography plays a central and increasingly important role in medical imaging. From the very beginning more than 30 years ago, computed tomography technology has continued to develop and provide a wide variety of applications for evaluation of disorders of virtually any organ system in both children and adults. The benefits are particularly evident with the newer, fast, high-resolution multidetector scanners. However, these benefits must be carefully weighed against the potential risks, which include a relatively high radiation dose. Current research efforts are directed at both further improvements in the diagnostic potential with computed tomography, as well as managing radiation dose.
One of the principal benefits of contemporary multidetector row computed tomography (MDCT) has been the ability to obtain high-quality data sets for evaluation of the cardiovascular system. The benefits of the greater number of detector rows and submillimeter image thicknesses were quickly recognized and are especially advantageous in children. For example, since imaging is performed so quickly, issues with motion are minimized. This is a substantial benefit of CTA compared with MR imaging, the traditional noninvasive cross sectional modality for pediatric cardiovascular imaging. This, together with faster and more powerful computers, including improved transfer and storage capabilities, offers improved depiction of the heart, great vessels, other vasculature, and adjacent intrathoracic structures in a fashion that is well accepted by clinical colleagues. In order to be successful, however, one must have an understanding of the technology and often unique technical considerations in infants and children. With this familiarity, excellent cardiovascular examinations can be performed even in the most challenging case.
Over the past three decades, computed tomography (CT) has proven to be central in imaging evaluation. Multidetector technology continues to drive practice patterns by combining fast scanning with high quality data sets. This has resulted in new applications as well as improved use in traditional applications. With this recognition has also come the realization that there are potential costs of CT. One major cost is the radiation dose. Therefore, in order to begin to assess benefits (which are relatively familiar to radiologists) versus costs (which are less familiar), the issues related to CT radiation need to be addressed. Familiarity with measures of CT radiation and the actual doses delivered by CT are important issues as they provide a basis for understanding the potential cancer risks from CT radiation. Moreover, these justify development of strategies to minimize radiation dose. Strategies include obtaining only necessary CT examinations and adjusting the examinations based on scan indication, region examined, and patient size. These strategies must also be combined with efforts by manufacturers in development and implementation of technology aimed at radiation dose management, as well as efforts in research, education, and CT standards and regulation. This article reviews the subject of radiation dose with multidetector CT technology, including measures of CT radiation, the dose that can result from CT examinations, the risks of this amount of radiation, and strategies for minimizing CT radiation dose.
The MDCT has advantages that are uniquely suited to imaging of infants and children. This is one reason why the use of CT has continued to increase. There is also, however, an increased complexity with this technology. Because diagnosis is dependent on adequate quality, and inappropriately high radiation doses can result from poor technique, it is necessary for the radiologist to be familiar with the techniques of MDCT in children. With attention to these techniques, and appropriate application of MDCT, it is possible to maximize the yield while minimizing the risk to children.
RATIONALE AND OBJECTIVES: The purpose of this study was twofold: (a) to compare the radiation dose profile between computed tomography (CT) with a single detector row (SD) and with a multi-detector row (MD) and (b) to compare specific organ doses between SD CT and MD CT. MATERIALS AND METHODS: Thermoluminescent dosimeters placed within a 32-cm-diameter cylindrical phantom were used to measure and compare dose profiles from one SD CT scanner and from one MD CT scanner. SD CT scanning parameters were 210 mA, 140 kVp, pitch of 1.0, 5-mm section thickness, and 0.8-second gantry rotation speed. MD CT scanning parameters were 130 mA, 140 kVp, pitch of 0.75, 4 x 5-mm section thickness, 15-mm table feed, and 0.8-second gantry rotation speed. To plot radiation dose profile, doses were measured both in the imaging plane and in the area adjacent to the imaging plane. The resultant data were normalized to achieve constant image noise between MD CT and SD CT. Direct doses to individual organs from primary and scattered radiation were measured with an anthropomorphic phantom containing thermoluminescent dosimeters and with a standard pelvic imaging protocol for both MD CT and SD CT. RESULTS: MD CT resulted in a dose profile approximately 27% higher than that from SD CT in the plane of imaging (8.0 vs 6.3 mGy) and 69% higher adjacent to the plane of imaging (6.8 vs 4.0 mGy). The individual doses to the kidneys, uterus, ovaries, and pelvic bone marrow were 92%-180% higher with MD CT than with SD CT. CONCLUSION: With image noise constant between SD CT and MD CT, the radiation dose profile both inside and outside the plane of imaging was higher with MD CT than with SD CT. Organ dose also was higher with MD CT than with SD CT. This difference should be accounted for in the design of MD CT protocols, especially as MD CT technology becomes more widely available for clinical use.
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Computed tomography (CT) is an extremely valuable diagnostic tool. Recent advances, particularly multidetector technology, have provided increased and more diverse applications. However, there is also the potential for inappropriate use and unnecessary radiation dose. Because some data indicate that low-dose radiation (such as that in CT) may have a significant risk of cancer, especially in young children, it is important to limit CT radiation by following the ALARA (as low as reasonably achievable) principle. There is a variety of strategies to limit radiation dose, including performing only necessary examinations, limiting the region of coverage, and adjusting individual CT settings based on indication, region imaged, and size of the child. The pediatric health care provider has a pivotal role in the performance of CT and may be the only individual who discusses these important CT radiation issues with the child and family. For this reason, this article will summarize the issues with CT patterns of use and radiation risk, and provide dose reduction strategies pertinent to pediatric health care providers.
OBJECTIVE: Our purpose was to assess the current practice of helical CT of the body in pediatric patients through a survey of members of the Society for Pediatric Radiology. MATERIALS AND METHODS: The survey consisted of 53 questions addressing demographics; oral and IV contrast media administration; and age-based (age groups, 0-4, 5-8, 9-12, and 13-16 years) scanning parameters, including tube current, kilovoltage, slice thickness, and pitch. Respondents accessed the Web-based survey via a uniform resource locator link included in an e-mail to the members of the Society for Pediatric Radiology automatically sent every week for three weeks. Survey results were automatically tabulated. RESULTS: Most (83%) respondents were based in children's or university hospitals at the time of the survey. Virtually all (99%) used nonionic IV contrast material. For body scanning, 21-32% used less than 2.0 mL/kg of body weight; we found the percentage of respondents who used power injection to be approximately equal to the percentage of those who used manual injection (47%). Age-based adjustments are made; however, 11-26% of CT examinations of children younger than 9 years are performed using more than 150 mA. A notable finding was that 20-25% of respondents did not know specific parameters used for their examinations. CONCLUSION: Although pediatric radiologists do practice age-adjusted helical CT, variable scanning techniques are used, potentially delivering high doses of radiation. Information on current practices in helical CT of the body in children can serve as a foundation for future recommendations and investigations into helical CT in pediatric patients.
OBJECTIVE: The purpose of our study was to evaluate the amount of radiation dose reduction and its effect on image quality when using an in-plane bismuth breast shield for multidetector CT (MDCT) of the chest and abdomen in female pediatric patients. SUBJECTS AND METHODS: Fifty consecutive MDCT examinations (chest, 29; abdomen, 21) of female pediatric patients (mean age, 9 years; range, 2 months-18 years) were performed with a 2-ply (1.7 g of bismuth per square centimeter) bismuth shield (three sizes to accommodate patients of varying sizes) overlying the patient's breasts. MDCT images were evaluated for a perceptible difference in image quality in the lungs at the anatomic level under the shield as compared with nonshielded lung and whether the images were of diagnostic quality. In addition, 2-mm regions of interest were placed in the peripheral anterior and posterior portions of each lung in shielded and nonshielded areas, and noise (standard deviation in Hounsfield units) was measured in the regions. Differences among the regions in noise were compared for shielded versus nonshielded areas (paired t test). To measure differences in actual dose, we also evaluated the breast shield with an infant anthropomorphic phantom using thermoluminescent detectors in the breast tissue. The phantom was imaged with and without the breast shield using identical MDCT parameters. RESULTS: All MDCT scans of patients were of diagnostic quality with no perceptible difference in image quality in shielded versus nonshielded lung. We found no statistically significant difference in noise between the shielded and nonshielded lung regions of interest (shielded: mean noise, 17.3 H; nonshielded: mean noise, 18.8 H; p = 0.5180). Phantom measurements revealed a 29% reduction in radiation dose to the breast when a medium-dose MDCT protocol was used. CONCLUSION: Bismuth in-plane breast shielding for pediatric MDCT decreased radiation dose to the breast without qualitative or quantitative changes in image quality.
OBJECTIVE: The purpose of this study was to evaluate the CT appearance, management, and temporal course of persistent pulmonary interstitial emphysema in neonates. MATERIALS AND METHODS: Criteria for inclusion in the study group included neonates with a history of prematurity who required ventilation for lung disease, development of hyperexpanded radiolucent lung lesions after typical radiographic findings of pulmonary interstitial emphysema, and CT documentation of lung abnormalities. Radiographs and CT scans were reviewed for the anatomic distribution, appearance, and presence of classic lines or dots within a radiolucent mass. We compared the management (surgical vs nonsurgical) and the temporal course in nonsurgical cases for patients in the United States and patients outside the United States. RESULTS: From seven institutions, we identified 17 patients who had persistent pulmonary interstitial emphysema with CT documentation. On CT, all lesions consisted of hyperexpanded cystic radiolucencies. Distribution was single-lobe in nine patients (left upper lobe, n = 5; left lower lobe, n = 3; right middle lobe, n = 1), multilobar in eight patients, and bilateral in six patients. Fourteen patients (82%) showed the characteristic line-and-dot pattern. All patients were initially treated conservatively; nine eventually underwent surgical resection with confirmation at pathology. Of 10 patients who underwent nonsurgical treatment for at least 1 year, lesions resolved in four patients, decreased in size in three asymptomatic patients, and enlarged in three patients, with eventual resection in two. Surgical resection was performed in 89% (8/9) of patients treated in the United States and in 13% (1/8) of patients treated outside the United States. CONCLUSION: Our study found that 82% of patients with persistent pulmonary interstitial emphysema had characteristic CT findings (central lines and dots surrounded by radiolucency). Although most patients in this series eventually underwent surgical resection, initial treatment can be conservative. The decision to perform surgery may have reflected the local medical culture.