International round-robin experiment for angle-resolved light scattering measurement.

An international round-robin experiment has been conducted to test procedures and methods for the measurement of angle-resolved light scattering. ASTM E2387-05 has been used as the main guide, while the experience gained should also contribute to the new ISO standard of angle-resolved scattering currently under development (ISO/WD 19986:2016). Seven laboratories from Europe and the United States measured the angle-resolved scattering from Al/SiO2-coated substrates, transparent substrates, volume diffusors, quasi-volume diffusors, white calibration standards, and grating samples at laser wavelengths in the UV, VIS, and NIR spectra. Results were sent to Fraunhofer IOF, which coordinated the experiments and analyzed the data, while ESA-ESTEC, as the project donor, defined conditions and parameters. Depending mainly on the sample type, overall good to reasonable agreements were observed, with largest deviations at scattering angles very close to the specular beam. Volume diffusor characterization unexpectedly turned out to be challenging. Not all participants provided measurement uncertainty ranges according to the Guide to the Expression of Uncertainty in Measurement; often, a single general scatterometer-related measurement uncertainty value was stated. Although relative instrument measurement uncertainties close to 1% are sometimes claimed, the comparison results did not support these claims for specular scattering samples as mirrors, substrates, or gratings.

Millimeter-Wave Beam Scattering by Field-Aligned Blobs in Simple Magnetized Toroidal Plasmas.

The first direct experimental measurements of the scattering of a millimeter-wave beam by plasma blobs in a simple magnetized torus are reported. The wavelength of the beam is comparable to the characteristic size of the blob. In situ Langmuir probe measurements show that fluctuations of the electron density induce correlated fluctuations of the transmitted power. A first-principles full-wave model, using conditionally sampled 2D electron density profiles, predicts fluctuations of the millimeter-wave power that are in agreement with experiments.

The Late-Career Radiologist: Options and Opportunities.

More than 25% of the present radiology workforce, or nearly 8300 radiologists, are actively practicing late-career radiologists. While these individuals could decide to retire from active practice, their continued presence in the workforce helps to maintain adequate and appropriate patient imaging services. To ensure their continued participation, issues important to all late-career radiologists need to be appreciated, discussed, and addressed. These issues include call-duty requirements, compensation, physical and cognitive health, and organized phase-out programs. The gamut of these issues is addressed in this review article. ©RSNA, 2018.

3D printing from diagnostic images: a radiologist's primer with an emphasis on musculoskeletal imaging-putting the 3D printing of pathology into the hands of every physician.

Three-dimensional (3D) printing has recently erupted into the medical arena due to decreased costs and increased availability of printers and software tools. Due to lack of detailed information in the medical literature on the methods for 3D printing, we have reviewed the medical and engineering literature on the various methods for 3D printing and compiled them into a practical "how to" format, thereby enabling the novice to start 3D printing with very limited funds. We describe (1) background knowledge, (2) imaging parameters, (3) software, (4) hardware, (5) post-processing, and (6) financial aspects required to cost-effectively reproduce a patient's disease ex vivo so that the patient, engineer and surgeon may hold the anatomy and associated pathology in their hands.

Incidence and acute complications of asymptomatic central venous catheter-related deep venous thrombosis in critically ill children.

OBJECTIVE: To determined the current incidence and acute complications of asymptomatic central venous catheter (CVC)-related deep venous thrombosis (DVT) in critically ill children. STUDY DESIGN: We performed a prospective cohort study in 3 pediatric intensive care units. A total of 101 children with newly inserted untunneled CVC were included. CVC-related DVT was diagnosed using compression ultrasonography with color Doppler. RESULTS: Asymptomatic CVC-related DVT was diagnosed in 16 (15.8%) children, which equated to 24.7 cases per 1000 CVC-days. Age was independently associated with DVT. Compared with children aged <1 year, children aged >13 years had significantly higher odds of DVT (aOR, 14.1, 95% CI, 1.9-105.8; P = .01). Other patient demographics, interventions (including anticoagulant use), and CVC characteristics did not differ between children with and without DVT. Mortality-adjusted duration of mechanical ventilation, a surrogate for pulmonary embolism, was statistically similar in the 2 groups (22 ± 9 days in children with DVT vs 23 ± 7 days in children without DVT; P = .34). Mortality-adjusted intensive care unit and hospital lengths of stay also were similar in the 2 groups. CONCLUSION: Asymptomatic CVC-related DVT is common in critically ill children. However, the acute complications do not seem to differ between children with and without DVT. Larger studies are needed to confirm these results. Future studies should also investigate the chronic complications of asymptomatic CVC-related DVT.

Using an Annual Diversity, Equity and Inclusion Dashboard to Accelerate Change in Academic Radiology Departments.

Despite widespread interest in creating a more equitable and inclusive culture, a lack of workforce diversity persists in Radiology, in part due to a lack of universal and longitudinal metrics across institutions. In an attempt to establish benchmarks, a subset of the Society of Chairs of Academic Radiology Departments (SCARD) Diversity, Equity and Inclusion (DEI) Committee volunteered to design a DEI dashboard as a potential tool for academic radiology programs to use to document and track their progress. This freely-available, modular dashboard includes suggested (plus optional department-defined) DEI activities/parameters and suggested assessment criteria across three domains: faculty, residents & fellows, and medical students; it can be completed, in whole or in part, by departmental leaders annually. The suggested metrics and their associated rubrics were derived from the collective experiences of the five working group members, all of whom are chairs of academic radiology departments. The resulting dashboard was unanimously approved by the remaining 14 DEI committee members and endorsed by the SCARD board of directors.

A 1-Tesla MRI system for dedicated brain imaging in the neonatal intensive care unit.

Objective: To assess the feasibility of a point-of-care 1-Tesla MRI for identification of intracranial pathologies within neonatal intensive care units (NICUs). Methods: Clinical findings and point-of-care 1-Tesla MRI imaging findings of NICU patients (1/2021 to 6/2022) were evaluated and compared with other imaging modalities when available. Results: A total of 60 infants had point-of-care 1-Tesla MRI; one scan was incompletely terminated due to motion. The average gestational age at scan time was 38.5 ± 2.3 weeks. Transcranial ultrasound (n = 46), 3-Tesla MRI (n = 3), or both (n = 4) were available for comparison in 53 (88%) infants. The most common indications for point-of-care 1-Tesla MRI were term corrected age scan for extremely preterm neonates (born at greater than 28 weeks gestation age, 42%), intraventricular hemorrhage (IVH) follow-up (33%), and suspected hypoxic injury (18%). The point-of-care 1-Tesla scan could identify ischemic lesions in two infants with suspected hypoxic injury, confirmed by follow-up 3-Tesla MRI. Using 3-Tesla MRI, two lesions were identified that were not visualized on point-of-care 1-Tesla scan: (1) punctate parenchymal injury versus microhemorrhage; and (2) small layering IVH in an incomplete point-of-care 1-Tesla MRI with only DWI/ADC series, but detectable on the follow-up 3-Tesla ADC series. However, point-of-care 1-Tesla MRI could identify parenchymal microhemorrhages, which were not visualized on ultrasound. Conclusion: Although limited by field strength, pulse sequences, and patient weight (4.5 kg)/head circumference (38 cm) restrictions, the Embrace® point-of-care 1-Tesla MRI can identify clinically relevant intracranial pathologies in infants within a NICU setting.

Diagnosis of intussusception by physician novice sonographers in the emergency department.

STUDY OBJECTIVE: We investigate the performance characteristics of bedside emergency department (ED) ultrasonography by nonradiologist physician sonographers in the diagnosis of ileocolic intussusception in children. METHODS: This was a prospective, observational study conducted in a pediatric ED of an urban tertiary care children's hospital. Pediatric emergency physicians with no experience in bowel ultrasonography underwent a focused 1-hour training session conducted by a pediatric radiologist. The session included a didactic component on sonographic appearances of ileocolic intussusception, review of images with positive and negative results for intussusceptions, and a hands-on component with a live child model. On completion of the training, a prospective convenience sample study was performed. Children were enrolled if they were to undergo diagnostic radiology ultrasonography for suspected intussusception. Bedside ultrasonography by trained pediatric emergency physicians was performed and interpreted as either positive or negative for ileocolic intussusception. Ultrasonographic studies were then performed by diagnostic radiologists, and their results were used as the reference standard. Test characteristics (sensitivity, specificity, positive and negative predictive values) and likelihood ratios were calculated. RESULTS: Six pediatric emergency physicians completed the training and performed the bedside studies. Eighty-two patients were enrolled. The median age was 25 months (range 3 to 127 months). Thirteen patients (16%) received a diagnosis of ileocolic intussusception by diagnostic radiology. Bedside ultrasonography had a sensitivity of 85% (95% confidence interval [CI] 54% to 97%), specificity of 97% (95% CI 89% to 99%), positive predictive value of 85% (95% CI 54% to 97%), and negative predictive value of 97% (95% CI 89% to 99%). A positive bedside ultrasonographic result had a likelihood ratio of 29 (95% CI 7.3 to 117), and a negative bedside ultrasonographic result had a likelihood ratio of 0.16 (95% CI 0.04 to 0.57). CONCLUSION: With limited and focused training, pediatric emergency physicians can accurately diagnose ileocolic intussusception in children by using bedside ultrasonography.

Medical imaging radiation safety for the female patient: rationale and implementation.

For the modern practitioner of women's imaging, achieving a balance between the positive diagnostic benefits available from current medical imaging on the one hand, and the potentially deleterious effects of ionizing radiation exposure on the other, has become a central issue. Increased public and professional awareness of the side effects of radiation now require a comprehensive understanding of the facts involved, the various risks to which patients are exposed, and the measures that can be implemented to minimize these risks. The major challenges posed by pregnancy, radiosensitive breast tissue, lactation, and an inability to easily exclude ovaries from the imaging field make female patients particularly vulnerable to medical imaging radiation exposure. The nature of this vulnerability changes frequently and depends on the imaging being performed, the age of the patient, and the clinical situation. For this reason, attention to gynecologic imaging radiation exposure across the whole life span is vitally important.

Directional control of neurite outgrowth: emerging technologies for Parkinson's disease using magnetic nanoparticles and magnetic field gradients.

A challenge in current stem cell therapies for Parkinson's disease (PD) is controlling neuronal outgrowth from the substantia nigra towards the targeted area where connectivity is required in the striatum. Here we present progress towards controlling directional neurite extensions through the application of iron-oxide magnetic nanoparticles (MNPs) labelled neuronal cells combined with a magnetic array generating large spatially variant field gradients (greater than 20 T m-1). We investigated the viability of this approach in both two-dimensional and organotypic brain slice models and validated the observed changes in neurite directionality using mathematical models. Results showed that MNP-labelled cells exhibited a shift in directional neurite outgrowth when cultured in a magnetic field gradient, which broadly agreed with mathematical modelling of the magnetic force gradients and predicted MNP force direction. We translated our approach to an ex vivo rat brain slice where we observed directional neurite outgrowth of transplanted MNP-labelled cells from the substantia nigra towards the striatum. The improved directionality highlights the viability of this approach as a remote-control methodology for the control and manipulation of cellular growth for regenerative medicine applications. This study presents a new tool to overcome challenges faced in the development of new therapies for PD.

Sawtooth pacing by real-time auxiliary power control in a tokamak plasma.

In the standard scenario of tokamak plasma operation, sawtooth crashes are the main perturbations that can trigger performance-degrading, and potentially disruption-generating, neoclassical tearing modes. This Letter demonstrates sawtooth pacing by real-time control of the auxiliary power. It is shown that the sawtooth crash takes place in a reproducible manner shortly after the removal of that power, and this can be used to precisely prescribe, i.e., pace, the individual sawteeth. In combination with preemptive stabilization of the neoclassical tearing modes, sawtooth pacing provides a new sawtooth control paradigm for improved performance in burning plasmas.

Intraepithelial lymphocytes. Anatomical site, not T cell receptor form, dictates phenotype and function.

The function and structure of the TCR proteins of intraepithelial lymphocytes (IEL) were examined using a panel of mAbs specific for TCR-gamma/delta. Three subsets of TCR-gamma/delta+ IEL could be detected with five mAbs, termed GL1-GL5. The mAbs were able to trigger lysis via crosslinking of the IEL TCR and all of the subsets were constitutively cytolytic. Immunoprecipitation of IEL TCR proteins revealed that the GL2 mAb reacted only with gamma, delta heterodimers containing high Mr delta chains, while the other mAbs precipitated all of the observed gamma and delta proteins. Two-color fluorescence analysis showed that the GL2+ subset was contained within the larger GL1+ subset. The GL3 and GL4 mAbs appear to be specific for all TCR-gamma/delta while GL2 was V delta 4 specific. Analysis of IEL for TCR-alpha/beta expression demonstrated that approximately 20% of B6 IEL were TCR-alpha/beta+. Interestingly, this population of IEL contained Thy-1- and CT1+ cells, indicating that the unique phenotype of IEL was not restricted to TCR-gamma/delta+ cells. Moreover, the TCR-alpha/beta+ IEL were also constitutively cytolytic, suggesting that the intestinal milieu was controlling the functional programming of IEL regardless of TCR type. The mAbs reported here as well as the ability to exploit the distinct phenotype of IEL should prove useful in determining the function of IEL and the TCR-gamma/delta.

Dysphagia testing and aspiration status in medically stable infants requiring mechanical ventilation via tracheotomy.

OBJECTIVE: To perform objective testing to determine aspiration status with the goal of initiating safe and timely oral alimentation in medically stable infants who require mechanical ventilation via tracheotomy. Medically compromised infants who require mechanical ventilation via tracheotomy and are nil by mouth are conventionally deemed as being at risk for aspiration and feeding difficulties. There is little information available in the literature regarding diagnostic testing and habilitation intervention to promote safe and timely initiation of oral alimentation when these infants are medically stable. DESIGN: Prospective, consecutive, referral-based sample. SETTING: Newborn, pediatric, and respiratory intensive care units in an urban, tertiary care, teaching hospital. PATIENTS: Fourteen consecutive medically stable but mechanically ventilated infants (mean chronological age, 8.1 mos, range, 3-14 mos; mean gestational age, 28.4 wks, range, 24-39 wks) referred for swallow evaluation between April 2003 and May 2008. INTERVENTIONS: Videofluoroscopic and fiberoptic endoscopic evluations of swallowing. MEASUREMENTS AND MAIN RESULTS: Aspiration status was determined by objective testing with videofluoroscopic and fiberoptic endoscopic evaluations of swallowing. Aspiration was defined as evidence of food material in the airway below the level of the true vocal folds. Eight infants exhibited a coordinated suck-swallow reflex, and six infants exhibited an oral dysphagia characterized by a weak, inconsistent, or absent suck. Nonetheless, 13 of 14 (93%) infants demonstrated a successful pharyngeal swallow with no evidence of aspiration and were started successfully on an oral diet. CONCLUSIONS: Objective dysphagia testing is recommended for medically stable infants who are ventilator dependent via a tracheotomy. The prevalence of aspiration in this group is low and a negative examination can promote safe and timely oral alimentation.

Routine exercise-based cardiac rehabilitation does not increase aerobic fitness: A CARE CR study.

BACKGROUND: Recent evidence suggests that routine exercise-based cardiac rehabilitation (CR) may not lead to a substantial increase in estimated peak oxygen uptake (V̇O2peak). This could reduce the potential benefits of CR and explain why CR no longer improves patient survival in recent studies. We aimed to determine whether routine exercise-based CR increases V̇O2peak using gold-standard maximal cardiopulmonary exercise testing (CPET), and to quantify the exercise training stimulus which might be insufficient in patients undertaking CR. METHODS: We studied the effects of a routine, twice weekly, exercise-based CR programme for eight weeks (intervention group) compared with abstention from supervised exercise training (control group) in patients with coronary heart disease. The primary outcome was V̇O2peak measured using CPET. We also measured changes in body composition using dual X-ray absorptiometry, carotid intima-media thickness, hs-CRP and N-terminal pro B-type natriuretic peptide at baseline, 10 weeks and 12 months. We also calculated the Calibre 5-year all-cause mortality risk score. RESULTS: Seventy patients (age 63.1 SD10.0 years; BMI 29.2 SD4.0 kg·m-2; 86% male) were recruited (n = 48 intervention; n = 22 controls). The mean aerobic exercise training duration was 23 min per training session, and the mean exercise training intensity was 45.9% of heart rate reserve. V̇O2peak was 23·3 ml·kg-1·min-1 at baseline, and there were no changes in V̇O2peak between groups at any time point. The intervention had no effect on any of the secondary endpoints. CONCLUSION: Routine CR does not lead to an increase in V̇O2peak and is unlikely to improve long-term physiological outcomes.

In vivo modulation of cytolytic activity and Thy-1 expression in TCR-gamma delta+ intraepithelial lymphocytes.

Although the functional aspects of the alpha beta T cell antigen receptor (TCR) found on most peripheral T cells are well described, the function of the gamma delta TCR remains unclear. Murine intraepithelial lymphocytes (IEL) of the small intestine are CD8+, express the gamma delta TCR, and are constitutively lytic. Fresh IEL from germ-free mice had no lytic activity. Moreover, whereas IEL from normal mice are 30 to 50 percent Thy-1+, IEL from germ-free did not express Thy-1. Acclimation of germ-free mice to nonsterile conditions resulted in the generation of Thy-1+ IEL and induction of lytic activity. Thus CD8+ TCR-gamma delta IEL were regulated by externally derived stimuli via a specific functional interaction between IEL and gut-associated antigens.

Optically isolated millimeter-wave detector for the Toroidal Plasma Experiment.

We have designed and built an optically isolated millimeter-wave detection system to prevent interference from a nearby, powerful, 2.45 GHz microwave source in millimeter-wave propagation experiments in the TORoroidal Plasma EXperiment (TORPEX). A series of tests demonstrates excellent system noise immunity and the ability to observe effects that cannot be resolved in a setup using a bare Schottky diode detector.

Elevated factor Xa activity in the blood of asymptomatic patients with congenital antithrombin deficiency.

The presence of congenital antithrombin deficiency has been consistently shown to predispose patients to venous thrombosis. We have utilized the prothrombin fragment F1+2 radioimmunoassay to quantitate factor Xa activity in the blood of 22 asymptomatic individuals with this clinical disorder not receiving antithrombotic therapy. The mean level of F1+2 was significantly elevated in these patients as compared to normal controls (3.91 vs. 1.97 nM, P less than 0.001). The metabolic behavior of 131 I-F1+2 was found to be similar in antithrombin-deficient subjects and normal individuals. The hemostatic system hyperactivity as measured by the F1+2 assay could be specifically corrected by raising the plasma antithrombin levels of the above asymptomatic individuals into the normal range. This study provides the first demonstration that the prethrombotic state can be biochemically defined as an imbalance between the production and inhibition of factor Xa enzymatic activity within the human circulation. It is known that antithrombin and alpha 1-proteinase inhibitor (PI) are the major inhibitors of factor Xa in human plasma in the absence of heparin. To further evaluate the mechanism by which antithrombin functions as an inhibitor of factor Xa in humans, we studied five patients who exhibited severe congenital deficiencies of alpha 1-PI. Our results indicated that the plasma of these subjects showed virtually identical decreases in plasma antifactor Xa activity in the absence of heparin when compared to antithrombin-deficient individuals, but the plasma F1+2 levels in the alpha 1-PI deficient population were not significantly different than normal. This data suggests that alpha 1-PI does not function as a major inhibitor of factor Xa in vivo, and that a tonically active heparin-dependent mechanism exists in humans for accelerating the neutralization of this enzyme by antithrombin.

Are abusive fractures in young children becoming less common? Changes over 24 years.

OBJECTIVE: To determine whether the proportion of fractures rated as abusive in children <36 months of age evaluated at a regional pediatric hospital increased over a 24-year period from 1979 to 2002. Fractures were chosen as an example of serious injuries in young children. METHODS: Medical records were abstracted for all children <36 months of age who were seen at a single pediatric hospital with a fracture during three time periods: 1979-1983, 1991-1994, and 1999-2002. After reviewing the abstracted and radiographic information, two clinicians (one an expert on child abuse) and two pediatric radiologists each rated the likelihood of abuse using explicit criteria and a seven-point scale from definite abuse to definite unintentional injury. Ratings were done independently; when disagreements occurred, the case was discussed, and a joint rating was agreed upon, if possible. The proportions of cases rated as abuse were compared over the three time periods, and logistic regression was used to calculate adjusted odds ratios (OR). RESULTS: In the early, middle, and late samples, there were 200, 240, and 232 children, respectively, with fractures. The proportion of cases rated as abuse decreased from 22.5% in the early period to 10.0% in the middle period and was 10.8% in the late period (p<.001). When comparing the odds of abuse in the middle and late groups to the odds of abuse in the early group (controlling for age, gender, ethnicity, type of medical insurance, and site of pediatric care), the adjusted ORs were .31 (95% CI=.15, .62) for the middle group and .45 (95% CI=.23, .86) for the late group. Thus, the odds of a given case being rated as abuse decreased by over 50% from the early period to the middle and late time periods. No statistically significant difference was found when comparing the odds of abuse for the middle group to those of the late group, OR: 1.46 (95% CI=.69, 3.08). CONCLUSIONS: The proportion of abusive fractures in young children decreased substantially from 1979-1983 to 1991-1994 and 1999-2002 at a major pediatric hospital. We speculate that this decrease may reflect early recognition of less serious forms of maltreatment and the availability of services to high-risk families.

Alanine aminotransferase levels and fatty liver in childhood obesity: associations with insulin resistance, adiponectin, and visceral fat.

BACKGROUND: Concurrent with the rise in obesity, nonalcoholic fatty liver disease is recognized as the leading cause of serum aminotransferase elevations in obese youth. Nevertheless, the complete metabolic phenotype associated with abnormalities in biomarkers of liver injury and intrahepatic fat accumulation remains to be established. METHODS: In a multiethnic cohort of 392 obese adolescents, alanine aminotransferase (ALT) levels were related with parameters of insulin sensitivity, glucose, and lipid metabolism as well as adipocytokines and biomarkers of inflammation. A subset of 72 adolescents had determination of abdominal fat partitioning and intrahepatic fat accumulation using magnetic resonance imaging. FINDINGS: Elevated ALT (> 35 U/liter) was found in 14% of adolescents, with a predominance of male gender and white/Hispanic race/ethnicity. After adjusting for potential confounders, rising ALT was associated with reduced insulin sensitivity and glucose tolerance as well as rising free fatty acids and triglycerides. Worsening of glucose and lipid metabolism was already evident as ALT levels rose into the upper half of the normal range (18-35 U/liter). When hepatic fat fraction was assessed using fast magnetic resonance imaging, 32% of subjects had an increased hepatic fat fraction, which was associated with decreased insulin sensitivity and adiponectin, and increased triglycerides, visceral fat, and deep to superficial sc fat ratio. The prevalence of the metabolic syndrome was significantly greater in those with fatty liver. INTERPRETATION: Deterioration in glucose and lipid metabolism is associated even with modest ALT elevations. Hepatic fat accumulation in childhood obesity is strongly associated with the triad of insulin resistance, increased visceral fat, and hypoadiponectinemia. Hence, hepatic steatosis may be a core feature of the metabolic syndrome.