Consensus statement on abusive head trauma in infants and young children

Abusive head trauma (AHT) is the leading cause of fatal head injuries in children younger than 2 years. A multidisciplinary team bases this diagnosis on history, physical examination, imaging and laboratory findings. Because the etiology of the injury is multifactorial (shaking, shaking and impact, impact, etc.) the current best and inclusive term is AHT. There is no controversy concerning the medical validity of the existence of AHT, with multiple components including subdural hematoma, intracranial and spinal changes, complex retinal hemorrhages, and rib and other fractures that are inconsistent with the provided mechanism of trauma. The workup must exclude medical diseases that can mimic AHT. However, the courtroom has become a forum for speculative theories that cannot be reconciled with generally accepted medical literature. There is no reliable medical evidence that the following processes are causative in the constellation of injuries of AHT: cerebral sinovenous thrombosis, hypoxic-ischemic injury, lumbar puncture or dysphagic choking/vomiting. There is no substantiation, at a time remote from birth, that an asymptomatic birth-related subdural hemorrhage can result in rebleeding and sudden collapse. Further, a diagnosis of AHT is a medical conclusion, not a legal determination of the intent of the perpetrator or a diagnosis of murder. We hope that this consensus document reduces confusion by recommending to judges and jurors the tools necessary to distinguish genuine evidence-based opinions of the relevant medical community from legal arguments or etiological speculations that are unwarranted by the clinical findings, medical evidence and evidence-based literature.

Survey of gadolinium-based contrast agent utilization among the members of the Society for Pediatric Radiology: a Quality and Safety Committee report

BACKGROUND

Gadolinium-based contrast agents (GBCAs) have been used for magnetic resonance (MR) imaging over the last three decades. Recent reports demonstrated gadolinium retention in patients' brains following intravenous administration. Since gadolinium is a highly toxic heavy metal, there is a potential for adverse effects from prolonged retention or deposition, particularly in children. For this reason, the Society (SPR) for Pediatric Radiology Quality and Safety committee conducted a survey to evaluate the current status of GBCAs usage among pediatric radiologists.

OBJECTIVE

To assess the usage of GBCAs among SPR members.

MATERIALS AND METHODS

An online 15-question survey was distributed to SPR members. Survey questions pertained to the type of GBCAs used, protocoling workflow, requirement of renal function or pregnancy tests, and various clinical indications for contrast-enhanced MRI examinations.

RESULTS

A total of 163 survey responses were compiled (11.1% of survey invitations), the majority of these from academic institutions in the United States. Ninety-four percent reported that MR studies are always or usually protocoled by pediatric radiologists. The most common GBCA utilized by survey respondents were Eovist (60.7%), Ablavar (45.4%), Gadovist (38.7%), Magnevist (34.4%) and Dotarem (32.5%). For several clinical indications, survey responses regarding GBCA administration were concordant with American College of Radiology (ACR) Appropriateness Criteria, including seizures, headache and osteomyelitis. For other indications, including growth hormone deficiency and suspected vascular ring, survey responses revealed potential overutilization of GBCAs when compared to ACR recommendations.

CONCLUSION

Survey results demonstrate that GBCAs are administered judiciously in children, yet there is an opportunity to improve their utilization with the goal of reducing potential future adverse effects.

What you need to know about statistics, part II: reliability of diagnostic and screening tests

The foundation for the usefulness of any diagnostic test should be that it is both reliable and accurate in its clinical diagnosis. In this article we present the second of a two-part series on validity and reliability, discussing the assessment of reliability among raters of diagnostic tests and between diagnostics tests themselves. To examine reproducibility (reliability) among raters of diagnostic tests we present the calculation of two statistical procedures: (1) the kappa coefficient statistic when presented with categorical data for the presence or absence of a clinical diagnosis and (2) the intraclass correlation coefficient (ICC) for continuously scaled data among raters. The accuracy among diagnostic tests (i.e. their interchangeability) can be evaluated by application of (1) a Bland-Altman plot procedure (with its 95% limits of agreement) and (2) the Passing-Bablok regression procedure (for the identification and evaluation of systematic and proportional differences). When deciding whether to select a diagnostic test one must evaluate its ability to provide more precise information than a gold standard test, and whether in clinical practice it would be more beneficial for patients to adopt it.

What you need to know about statistics Part I: validity of diagnostic and screening tests

The intent of this manuscript is to provide guidance and support to clinicians and investigators for reporting the results of screening and diagnostic tests. This article is the first of two parts addressing statistics in imaging research. In this part validity measures are discussed. In part II reliability measures will be discussed. In discussing validity, the following concepts will be introduced: (1) functions of diagnostic tests, (2) statistical characteristics of diagnostic tests and application of validity measures, (3) power and sample size for testing the sensitivity and specificity of the diagnostic test, (4) statistical versus clinical significance and (5) characteristics of a useful diagnostic test.

Neuroimaging and neurodevelopmental outcome in extremely preterm infants

BACKGROUND

Extremely preterm infants are at risk for neurodevelopmental impairment (NDI). Early cranial ultrasound (CUS) is usual practice, but near-term brain MRI has been reported to better predict outcomes. We prospectively evaluated MRI white matter abnormality (WMA) and cerebellar lesions, and serial CUS adverse findings as predictors of outcomes at 18 to 22 months' corrected age.

METHODS

Early and late CUS, and brain MRI were read by masked central readers, in a large cohort (n = 480) of infants <28 weeks' gestation surviving to near term in the Neonatal Research Network. Outcomes included NDI or death after neuroimaging, and significant gross motor impairment or death, with NDI defined as cognitive composite score <70, significant gross motor impairment, and severe hearing or visual impairment. Multivariable models evaluated the relative predictive value of neuroimaging while controlling for other factors.

RESULTS

Of 480 infants, 15 died and 20 were lost. Increasing severity of WMA and significant cerebellar lesions on MRI were associated with adverse outcomes. Cerebellar lesions were rarely identified by CUS. In full multivariable models, both late CUS and MRI, but not early CUS, remained independently associated with NDI or death (MRI cerebellar lesions: odds ratio, 3.0 [95% confidence interval: 1.3-6.8]; late CUS: odds ratio, 9.8 [95% confidence interval: 2.8-35]), and significant gross motor impairment or death. In models that did not include late CUS, MRI moderate-severe WMA was independently associated with adverse outcomes.

CONCLUSIONS

Both late CUS and near-term MRI abnormalities were associated with outcomes, independent of early CUS and other factors, underscoring the relative prognostic value of near-term neuroimaging.

Cancer risks associated with external radiation from diagnostic imaging procedures

The 600% increase in medical radiation exposure to the US population since 1980 has provided immense benefit, but increased potential future cancer risks to patients. Most of the increase is from diagnostic radiologic procedures. The objectives of this review are to summarize epidemiologic data on cancer risks associated with diagnostic procedures, describe how exposures from recent diagnostic procedures relate to radiation levels linked with cancer occurrence, and propose a framework of strategies to reduce radiation from diagnostic imaging in patients. We briefly review radiation dose definitions, mechanisms of radiation carcinogenesis, key epidemiologic studies of medical and other radiation sources and cancer risks, and dose trends from diagnostic procedures. We describe cancer risks from experimental studies, future projected risks from current imaging procedures, and the potential for higher risks in genetically susceptible populations. To reduce future projected cancers from diagnostic procedures, we advocate the widespread use of evidence-based appropriateness criteria for decisions about imaging procedures; oversight of equipment to deliver reliably the minimum radiation required to attain clinical objectives; development of electronic lifetime records of imaging procedures for patients and their physicians; and commitment by medical training programs, professional societies, and radiation protection organizations to educate all stakeholders in reducing radiation from diagnostic procedures.

Where we were, what has changed, what needs doing: a decade of progress

In the last decade, there has been recognition of the effects of low-dose radiation in children. A critical mass of scientists, health care providers and manufacturers of radiation-producing imaging equipment has come together to educate ordering physicians to request only indicated examinations and radiologists to achieve low-dose examinations with diagnostic images. The forces that caused these changes will be discussed.

Sedation and anesthesia issues in pediatric imaging

Sedation and anesthesia for pediatric imaging departments has changed dramatically for the following reasons: (1) radiologists have stopped sedating patients; (2) the majority of sedations are not for CT (because of the speed of the procedure) but for MR, which lasts 45 min or greater; (3) a cadre of services--pediatricians, emergency medicine physicians, hospitalists and intensivists, as well as anesthesiologists--can provide the services. These changes have significantly influenced the type of agents utilized for sedation and anesthesia and, most important, have created operational issues for MR departments. Nevertheless, it is important for each imaging department to create a uniform approach to sedation, taking into account patient expectations, efficiency of through-put, facilities and personnel available, and institutional costs.

The pediatric radiologist approaching retirement

Retirement can be defined as a new stage of an active lifestyle. It is a unique chapter in life that can be fun and rewarding, if steps are taken to plan the process. Key factors to take into consideration during this process are family, friends, finances, and professional interests. With proper planning, rather than withdrawing from an active life, retirees can embrace their new lifestyle with a fresh perspective.

Aerosol delivery in ventilated newborn pigs: an MRI evaluation

Pulmonary deposition of inhaled drugs in ventilated neonates has not been studied in vivo. The objective of this study was to evaluate pulmonary delivery of gadopentetate dimeglumine (Gd-DTPA) following nebulization in ventilated piglets using magnetic resonance imaging. Seven ventilated piglets (5 +/- 2 d old, weight 1.8 +/- 0.5 kg) were scanned in the Bruker/Siemens 4T magnetic resonance scanner using T1 weighted spin-echo sequence. Aerosols of Gd-DTPA were generated continuously using the MiniHeart jet nebulizer. Breath-hold coronal images were obtained before and every 10 min during aerosolized Gd-DTPA for 90 min. Signal intensity (SI) changes over the lungs, kidneys, liver, skeletal muscle, and heart were evaluated. A significant increase in SI was observed in the lungs, kidney, and liver at 10, 20, and 40 min respectively after start of aerosol. At the end of 90 min, the SI increased by 95%, 101%, and 426% over the right lung, left lung, and kidney, respectively. A much smaller increase in SI was observed over the liver. In conclusion, we have demonstrated effective pulmonary aerosol delivery within 10 min of contrast nebulization in ventilated piglets. Contrast visualization in the kidneys within 20 min of aerosol initiation reflects alveolar absorption, glomerular filtration and renal concentration.

Practice parameter: neuroimaging of the neonate: report of the Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society

OBJECTIVE

The authors reviewed available evidence on neonatal neuroimaging strategies for evaluating both very low birth weight preterm infants and encephalopathic term neonates.

IMAGING FOR THE PRETERM NEONATE

Routine screening cranial ultrasonography (US) should be performed on all infants of <30 weeks' gestation once between 7 and 14 days of age and should be optimally repeated between 36 and 40 weeks' postmenstrual age. This strategy detects lesions such as intraventricular hemorrhage, which influences clinical care, and those such as periventricular leukomalacia and low-pressure ventriculomegaly, which provide information about long-term neurodevelopmental outcome. There is insufficient evidence for routine MRI of all very low birth weight preterm infants with abnormal results of cranial US.

IMAGING FOR THE TERM INFANT

Noncontrast CT should be performed to detect hemorrhagic lesions in the encephalopathic term infant with a history of birth trauma, low hematocrit, or coagulopathy. If CT findings are inconclusive, MRI should be performed between days 2 and 8 to assess the location and extent of injury. The pattern of injury identified with conventional MRI may provide diagnostic and prognostic information for term infants with evidence of encephalopathy. In particular, basal ganglia and thalamic lesions detected by conventional MRI are associated with poor neurodevelopmental outcome. Diffusion-weighted imaging may allow earlier detection of these cerebral injuries.

RECOMMENDATIONS

US plays an established role in the management of preterm neonates of <30 weeks' gestation. US also provides valuable prognostic information when the infant reaches 40 weeks' postmenstrual age. For encephalopathic term infants, early CT should be used to exclude hemorrhage; MRI should be performed later in the first postnatal week to establish the pattern of injury and predict neurologic outcome.