Compact pediatric cardiac magnetic resonance imaging protocols.

Cardiac MRI is in many respects an ideal modality for pediatric cardiovascular imaging, enabling a complete noninvasive assessment of anatomy, morphology, function and flow in one radiation-free and potentially non-contrast exam. Nonetheless, traditionally lengthy and complex imaging acquisition strategies have often limited its broader use beyond specialized centers. In this review, the author presents practical cardiac MRI imaging protocols to facilitate the performance of succinct yet successful exams that provide the most salient clinical data for the majority of congenital and acquired pediatric cardiac disease. In addition, the author reviews newer and evolving techniques that permit more rapid but similarly diagnostic MRI, including compressed sensing and artificial intelligence/machine learning reconstruction, four-dimensional flow acquisition and blood pool contrast agents. With the modern armamentarium of cardiac MRI methods, the goal of compact yet comprehensive exams in children can now be realized.

Postoperative Acute Kidney Injury in Williams Syndrome Compared With Matched Controls.

OBJECTIVES: Cardiovascular manifestations occur in over 80% of Williams syndrome (WS) patients and are the leading cause of morbidity and mortality. One-third of patients require cardiovascular surgery. Renal artery stenosis (RAS) is common in WS. No studies have assessed postoperative cardiac surgery-related acute kidney injury (CS-AKI) in WS. Our objectives were to assess if WS patients have higher risk of CS-AKI postoperatively than matched controls and if RAS could contribute to CS-AKI. DESIGN: This was a retrospective study of all patients with WS who underwent cardiac surgery at our center from 2010 to 2020. The WS study cohort was compared with a group of controls matched for age, sex, weight, and surgical procedure. SETTING: Patients underwent cardiac surgery and postoperative care at Lucile Packard Children's Hospital Stanford. PATIENTS: There were 27 WS patients and 43 controls (31% vs 42% female; p = 0.36). Median age was 1.8 years (interquartile range [IQR], 0.7-3.8 yr) for WS and 1.7 years (IQR, 0.8-3.1 yr) for controls. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Postoperative hemodynamics, vasopressor, total volume input, diuretic administration, and urine output were collected in the first 72 hours. Laboratory studies were collected at 8-hour intervals. Multivariable analysis identified predictors of CS-AKI.Controlled for renal perfusion pressure (RPP) and vasoactive inotrope score (VIS), compared with controls, the odds ratio (OR) of CS-AKI in WS was 4.2 (95% CI, 1.1-16; p = 0.034). Higher RPP at postoperative hours 9-16 was associated with decreased OR of CS-AKI (0.88 [0.8-0.96]; p = 0.004). Increased VIS at hour 6 was associated with an increased OR of CS-AKI (1.47 [1.14-1.9]; p = 0.003). Younger age was associated with an increased OR of CS-AKI (1.9 [1.13-3.17]; p = 0.015). CONCLUSIONS: The OR of CS-AKI is increased in pediatric patients with WS compared with controls. CS-AKI was associated with VIS at the sixth postoperative hour. Increases in RPP and mean arterial pressure were associated with decreased odds of CS-AKI.

Computed tomography in tetralogy of Fallot: pre- and postoperative imaging evaluation.

Tetralogy of Fallot (TOF) is the most common cause of cyanotic congenital heart disease (CHD) and the most frequent complex CHD encountered in adulthood. Although children with TOF share four characteristic features (subaortic ventricular septal defect, overriding aorta, right ventricular hypertrophy, pulmonary stenosis), the clinical spectrum and course are in fact greatly heterogeneous. Echocardiography remains the mainstay for diagnosis, presurgical planning and postoperative follow-up. However, with continued technological advances, CT now plays an increasing role in TOF evaluation and management, helping to minimize routine invasive catheter angiography. Preoperatively, CT is uniquely suited to assess associated pulmonary arterial, aortic and coronary anomalies as well as extra-cardiovascular structures and is particularly helpful for delineating complex anatomy in the TOF subtypes of absent pulmonary valve and pulmonary atresia with major aortopulmonary collaterals. Postoperatively, CT is useful for identifying surgical complications and for long-term monitoring including volumetry quantification, especially in children for whom MRI is contraindicated or limited by implanted devices such as pacemakers and stents. In this article, we review key clinical features and considerations in the pre- and postoperative TOF patient and the burgeoning role of CT for facilitating accurate diagnosis and personalized intervention.

Pediatric cardiothoracic vasculitis: multimodality imaging review.

The pediatric vasculitides are a relatively uncommon and heterogeneous group of disorders characterized by vessel inflammation, often with cardiothoracic involvement. Diagnosis and monitoring are often clinically challenging because of the nonspecific symptoms and laboratory markers. Thus, imaging has assumed increasing importance for early detection of disease activity, extent and complications as well as long-term monitoring pre- and post-treatment. Herein, we review the major pediatric vasculitides with frequent chest manifestations, including Takayasu arteritis, Kawasaki disease, granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, microscopic polyangiitis, Behçet disease and potential mimics. We highlight key clinical features and management considerations, emphasizing the central role of imaging.

Free-breathing Accelerated Cardiac MRI Using Deep Learning: Validation in Children and Young Adults.

Background Obtaining ventricular volumetry and mass is key to most cardiac MRI but challenged by long multibreath-hold acquisitions. Purpose To assess the image quality and performance of a highly accelerated, free-breathing, two-dimensional cine cardiac MRI sequence incorporating deep learning (DL) reconstruction compared with reference standard balanced steady-state free precession (bSSFP). Materials and Methods A DL algorithm was developed to reconstruct custom 12-fold accelerated bSSFP cardiac MRI cine images from coil sensitivity maps using 15 iterations of separable three-dimensional convolutions and data consistency steps. The model was trained, validated, and internally tested in 10, two, and 10 adult human volunteers, respectively, based on vendor partner-supplied fully sampled bSSFP acquisitions. For prospective external clinical validation, consecutive children and young adults undergoing cardiac MRI from September through December 2019 at a single children's hospital underwent both conventional and highly accelerated short-axis bSSFP cine acquisitions in one MRI examination. Two radiologists scored overall and volumetric three-dimensional mesh image quality of all short-axis stacks on a five-point Likert scale and manually segmented endocardial and epicardial contours. Scan times and image quality were compared using the Wilcoxon rank sum test. Measurement agreement was assessed with intraclass correlation coefficient and Bland-Altman analysis. Results Fifty participants (mean age, 16 years ± 4 [standard deviation]; range, 5-30 years; 29 men) were evaluated. The mean prescribed acquisition times of accelerated scans (non-breath-held) and bSSFP (excluding breath-hold time) were 0.9 minute ± 0.3 versus 3.0 minutes ± 1.9 (P < .001). Overall and three-dimensional mesh image quality scores were, respectively, 3.8 ± 0.6 versus 4.3 ± 0.6 (P < .001) and 4.0 ± 1.0 versus 4.4 ± 0.8 (P < .001). Raters had strong agreement between all bSSFP and DL measurements, with intraclass correlation coefficients of 0.76 to 0.97, near-zero mean differences, and narrow limits of agreement. Conclusion With slightly lower image quality yet much faster speed, deep learning reconstruction may allow substantially shorter acquisition times of cardiac MRI compared with conventional balanced steady-state free precession MRI performed for ventricular volumetry. © RSNA, 2021 Online supplemental material is available for this article.

Increasing the Utilization of Moderate Sedation Services for Pediatric Imaging.

Performing motion-free imaging is frequently challenging in children. To bridge the gap between examinations performed in children who are awake and in those under general anesthesia, a moderate sedation program was implemented at our institution but was seldom used despite substantial eligibility. In conjunction with a 5-month quality improvement (QI) course, a multidisciplinary team was assembled and, by using an A3 approach, sought to address the most important key drivers of low utilization, namely the need for clear moderate sedation eligibility criteria, reliable protocol routing order, consistent moderate sedation screening performed by registered nurses (RNs), and enhanced visibility of moderate sedation services to ordering providers. Initial steps focused on developing better-defined criteria and protocoling standard work for technologists and RNs, with coaching and audits. Modality-specific forecasting was then implemented to reroute profiles of patients who were awaiting scheduling or already scheduled for an examination with general anesthesia to the moderate sedation queue to identify more eligible patients. These manual efforts were coupled with higher reliability but more protracted electronic health record changes, facilitating automated protocol routing on the basis of moderate sedation eligibility and order entry constraints. As a result, scheduled imaging examinations requiring moderate sedation increased from a mean of 1.2 examinations per week to a sustained 6.1 examinations per week (range, 4-8) over the 5-month period, exceeding the team SMART (specific, measurable, achievable, relevant, and time bound) goal to achieve an average of five examinations per week by the QI course end. By targeting the most high-impact yet modifiable process deficiencies through a multifaceted team approach and initially investing in manual efforts to gain cultural buy-in while awaiting higher-reliability interventions, the project achieved success and may serve as a more general model for workflow change when there is organizational resistance. ©RSNA, 2021.

Clinical use of shear-wave elastography for detecting liver fibrosis in children and adolescents with cystic fibrosis.

BACKGROUND: Complications from liver cirrhosis are a leading cause of death in children with cystic fibrosis. Identifying children at risk for developing liver cirrhosis and halting its progression are critical to reducing liver-associated mortality. OBJECTIVE: Quantitative US imaging, such as shear-wave elastography (SWE), might improve the detection of liver fibrosis in children with cystic fibrosis (CF) over gray-scale US alone. We incorporated SWE in our pediatric CF liver disease screening program and evaluated its performance using magnetic resonance (MR) elastography. MATERIALS AND METHODS: Ninety-four children and adolescents with CF underwent 178 SWE exams, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT) and platelet measurements. Of these, 27 children underwent 34 MR elastography exams. We evaluated SWE performance using 6-MHz and 9-MHZ point SWE, and 9-MHz two-dimensional (2-D) SWE. RESULTS: The 6-MHz point SWE was the only method that correlated with MR elastography (r=0.52; 95% confidence interval [CI] 0.20-0.74; P=0.003). SWE of 1.45 m/s distinguished normal from abnormal MR elastography (79% sensitivity, 100% specificity, 100% positive predictive value [PPV], 55% negative predictive value [NPV], area under the receiver operating characteristic [AUROC] curve 0.94). SWE of 1.84 m/s separated mild-moderate (3.00-4.77 kPa) from severe (>4.77 kPa) MR elastography (88% sensitivity, 86% specificity, 78% PPV, 93% NPV, AUROC 0.79). Elevations of AST, ALT, GGT and thrombocytopenia were associated with higher SWE. AST-to-platelet ratio index of 0.42, fibrosis-4 of 0.29, and GGT-to-platelet ratio of 1.43 all had >95% NPV for SWE >1.84 m/s. CONCLUSION: Given its correlation with MR elastography, SWE might be a clinically useful predictor of liver fibrosis. We identified imaging criteria delineating the use of SWE to identify increased liver stiffness in children with CF. With multicenter validation, these data might be used to improve the detection and monitoring of liver fibrosis in children with CF.

Image-based scaling laws for somatic growth and pulmonary artery morphometry from infancy to adulthood.

Pulmonary artery (PA) morphometry has been extensively explored in adults, with particular focus on intra-acinar arteries. However, scaling law relationships for length and diameter of extensive preacinar PAs by age have not been previously reported for in vivo human data. To understand preacinar PA growth spanning children to adults, we performed morphometric analyses of all PAs visible in the computed tomography (CT) and magnetic resonance (MR) images from a healthy subject cohort [n = 16; age: 1-51 yr; body surface area (BSA): 0.49-2.01 m2]. Subject-specific anatomic PA models were constructed from CT and MR images, and morphometric information-diameter, length, tortuosity, bifurcation angle, and connectivity-was extracted and sorted into diameter-defined Strahler orders. Validation of Murray's law, describing optimal scaling exponents of radii for branching vessels, was performed to determine how closely PAs conform to this classical relationship. Using regression analyses of vessel diameters and lengths against orders and patient metrics (BSA, age, height), we found that diameters increased exponentially with order and allometrically with patient metrics. Length increased allometrically with patient metrics, albeit weakly. The average tortuosity index of all vessels was 0.026 ± 0.024, average bifurcation angle was 28.2 ± 15.1°, and average Murray's law exponent was 2.92 ± 1.07. We report a set of scaling laws for vessel diameter and length, along with other morphometric information. These provide an initial understanding of healthy structural preacinar PA development with age, which can be used for computational modeling studies and comparison with diseased PA anatomy.NEW & NOTEWORTHY Pulmonary artery (PA) morphometry studies to date have focused primarily on large arteries and intra-acinar arteries in either adults or children, neglecting preacinar arteries in both populations. Our study is the first to quantify in vivo preacinar PA morphometry changes spanning infants to adults. For preacinar arteries > 1 mm in diameter, we identify scaling laws for vessel diameters and lengths with patient metrics of growth and establish a healthy PA morphometry baseline for most preacinar PAs.

Rosette Trajectories Enable Ungated, Motion-Robust, Simultaneous Cardiac and Liver T2 * Iron Assessment.

BACKGROUND: Quantitative T2 * MRI is the standard of care for the assessment of iron overload. However, patient motion corrupts T2 * estimates. PURPOSE: To develop and evaluate a motion-robust, simultaneous cardiac and liver T2 * imaging approach using non-Cartesian, rosette sampling and a model-based reconstruction as compared to clinical-standard Cartesian MRI. STUDY TYPE: Prospective. PHANTOM/POPULATION: Six ferumoxytol-containing phantoms (26-288 µg/mL). Eight healthy subjects and 18 patients referred for clinically indicated iron overload assessment. FIELD STRENGTH/SEQUENCE: 1.5T, 2D Cartesian and rosette gradient echo (GRE) ASSESSMENT: GRE T2 * values were validated in ferumoxytol phantoms. In healthy subjects, test-retest and spatial coefficient of variation (CoV) analysis was performed during three breathing conditions. Cartesian and rosette T2 * were compared using correlation and Bland-Altman analysis. Images were rated by three experienced radiologists on a 5-point scale. STATISTICAL TESTS: Linear regression, analysis of variance (ANOVA), and paired Student's t-testing were used to compare reproducibility and variability metrics in Cartesian and rosette scans. The Wilcoxon rank test was used to assess reader score comparisons and reader reliability was measured using intraclass correlation analysis. RESULTS: Rosette R2* (1/T2 *) was linearly correlated with ferumoxytol concentration (r2 = 1.00) and not significantly different than Cartesian values (P = 0.16). During breath-holding, ungated rosette liver and heart T2 * had lower spatial CoV (liver: 18.4 ± 9.3% Cartesian, 8.8% ± 3.4% rosette, P = 0.02, heart: 37.7% ± 14.3% Cartesian, 13.4% ± 1.7% rosette, P = 0.001) and higher-quality scores (liver: 3.3 [3.0-3.6] Cartesian, 4.7 [4.1-4.9] rosette, P = 0.005, heart: 3.0 [2.3-3] Cartesian, 4.5 [3.8-5.0] rosette, P = 0.005) compared to Cartesian values. During free-breathing and failed breath-holding, Cartesian images had very poor to average image quality with significant artifacts, whereas rosette remained very good, with minimal artifacts (P = 0.001). DATA CONCLUSION: Rosette k-sampling with a model-based reconstruction offers a clinically useful motion-robust T2 * mapping approach for iron quantification. J. MAGN. RESON. IMAGING 2020;52:1688-1698.

Subsuns and rainbows during solar eclipses.

A photographic observation sequence was obtained of a subsun before, during, and after the total phase of the 2016 solar eclipse. The time-resolved images were obtained from a high-altitude jet aircraft. The image sequence was searched for the possible presence of a solar corona-generated subsun during totality. Although the subsun-creating conditions apparently persisted during totality, the drop in signal intensity compared to the local background prevented its detection. Separately, we document a visual observation from the 1977 total solar eclipse of a rainbow that faded, in the last a few seconds before totality, from being normally multicolored to monochromatic red from water drops then predominantly illuminated by light from the solar chromosphere. A similar transition in the final seconds before, and after, totality is expected to occur for parhelia. The posited short-living monochromatic red parhelion resulting from the momentary illumination of ice crystals by the solar chromosphere is still waiting to be observed.

Ultrafast pediatric chest computed tomography: comparison of free-breathing vs. breath-hold imaging with and without anesthesia in young children.

BACKGROUND: General anesthesia (GA) or sedation has been used to obtain good-quality motion-free breath-hold chest CT scans in young children; however pulmonary atelectasis is a common and problematic accompaniment that can confound diagnostic utility. Dual-source multidetector CT permits ultrafast high-pitch sub-second examinations, minimizing motion artifact and potentially eliminating the need for a breath-hold. OBJECTIVE: The purpose of this study was to evaluate the feasibility of free-breathing ultrafast pediatric chest CT without GA and to compare it with breath-hold and non-breath-hold CT with GA. MATERIALS AND METHODS: Young (≤3 years old) pediatric outpatients scheduled for chest CT under GA were recruited into the study and scanned using one of three protocols: GA with intubation, lung recruitment and breath-hold; GA without breath-hold; and free-breathing CT without anesthesia. In all three protocols an ultrafast high-pitch CT technique was used. We evaluated CT images for overall image quality, presence of atelectasis and motion artifacts. RESULTS: We included 101 scans in the study. However the GA non-breath-hold technique was discontinued after 15 scans, when it became clear that atelectasis was a major issue despite diligent attempts to mitigate it. This technique was therefore not included in statistical evaluation (86 remaining patients). Overall image quality was higher (P=0.001) and motion artifacts were fewer (P<.001) for scans using the GA with intubation and recruitment technique compared to scans in the non-GA free-breathing group. However no significant differences were observed regarding the presence of atelectasis between these groups. CONCLUSION: We demonstrated that although overall image quality was best and motion artifact least with a GA-breath-hold intubation and recruitment technique, free-breathing ultrafast pediatric chest CT without anesthesia provides sufficient image quality for diagnostic purposes and can be successfully performed both without and with contrast agent in young infants.

Cross-sectional imaging of thoracic traumatic aortic injury.

Aortic injury remains a major contributor to morbidity and mortality from acute thoracic trauma. While such injuries were once nearly uniformly fatal, the advent of cross-sectional imaging in recent years has facilitated rapid diagnosis and triage, greatly improving outcomes. In fact, cross-sectional imaging is now the diagnostic test of choice for traumatic aortic injury (TAI), specifically computed tomography angiography (CTA) in the acute setting and CTA or magnetic resonance angiography (MRA) in follow-up. In this review, we present an up-to-date discussion of acute traumatic thoracic aortic injury with a focus on optimal and emerging CT/MR techniques, imaging findings of TAI, and potential pitfalls.

Deep-learning-assisted diagnosis for knee magnetic resonance imaging: Development and retrospective validation of MRNet.

BACKGROUND: Magnetic resonance imaging (MRI) of the knee is the preferred method for diagnosing knee injuries. However, interpretation of knee MRI is time-intensive and subject to diagnostic error and variability. An automated system for interpreting knee MRI could prioritize high-risk patients and assist clinicians in making diagnoses. Deep learning methods, in being able to automatically learn layers of features, are well suited for modeling the complex relationships between medical images and their interpretations. In this study we developed a deep learning model for detecting general abnormalities and specific diagnoses (anterior cruciate ligament [ACL] tears and meniscal tears) on knee MRI exams. We then measured the effect of providing the model's predictions to clinical experts during interpretation. METHODS AND FINDINGS: Our dataset consisted of 1,370 knee MRI exams performed at Stanford University Medical Center between January 1, 2001, and December 31, 2012 (mean age 38.0 years; 569 [41.5%] female patients). The majority vote of 3 musculoskeletal radiologists established reference standard labels on an internal validation set of 120 exams. We developed MRNet, a convolutional neural network for classifying MRI series and combined predictions from 3 series per exam using logistic regression. In detecting abnormalities, ACL tears, and meniscal tears, this model achieved area under the receiver operating characteristic curve (AUC) values of 0.937 (95% CI 0.895, 0.980), 0.965 (95% CI 0.938, 0.993), and 0.847 (95% CI 0.780, 0.914), respectively, on the internal validation set. We also obtained a public dataset of 917 exams with sagittal T1-weighted series and labels for ACL injury from Clinical Hospital Centre Rijeka, Croatia. On the external validation set of 183 exams, the MRNet trained on Stanford sagittal T2-weighted series achieved an AUC of 0.824 (95% CI 0.757, 0.892) in the detection of ACL injuries with no additional training, while an MRNet trained on the rest of the external data achieved an AUC of 0.911 (95% CI 0.864, 0.958). We additionally measured the specificity, sensitivity, and accuracy of 9 clinical experts (7 board-certified general radiologists and 2 orthopedic surgeons) on the internal validation set both with and without model assistance. Using a 2-sided Pearson's chi-squared test with adjustment for multiple comparisons, we found no significant differences between the performance of the model and that of unassisted general radiologists in detecting abnormalities. General radiologists achieved significantly higher sensitivity in detecting ACL tears (p-value = 0.002; q-value = 0.019) and significantly higher specificity in detecting meniscal tears (p-value = 0.003; q-value = 0.019). Using a 1-tailed t test on the change in performance metrics, we found that providing model predictions significantly increased clinical experts' specificity in identifying ACL tears (p-value < 0.001; q-value = 0.006). The primary limitations of our study include lack of surgical ground truth and the small size of the panel of clinical experts. CONCLUSIONS: Our deep learning model can rapidly generate accurate clinical pathology classifications of knee MRI exams from both internal and external datasets. Moreover, our results support the assertion that deep learning models can improve the performance of clinical experts during medical imaging interpretation. Further research is needed to validate the model prospectively and to determine its utility in the clinical setting.

Deep learning for chest radiograph diagnosis: A retrospective comparison of the CheXNeXt algorithm to practicing radiologists.

BACKGROUND: Chest radiograph interpretation is critical for the detection of thoracic diseases, including tuberculosis and lung cancer, which affect millions of people worldwide each year. This time-consuming task typically requires expert radiologists to read the images, leading to fatigue-based diagnostic error and lack of diagnostic expertise in areas of the world where radiologists are not available. Recently, deep learning approaches have been able to achieve expert-level performance in medical image interpretation tasks, powered by large network architectures and fueled by the emergence of large labeled datasets. The purpose of this study is to investigate the performance of a deep learning algorithm on the detection of pathologies in chest radiographs compared with practicing radiologists. METHODS AND FINDINGS: We developed CheXNeXt, a convolutional neural network to concurrently detect the presence of 14 different pathologies, including pneumonia, pleural effusion, pulmonary masses, and nodules in frontal-view chest radiographs. CheXNeXt was trained and internally validated on the ChestX-ray8 dataset, with a held-out validation set consisting of 420 images, sampled to contain at least 50 cases of each of the original pathology labels. On this validation set, the majority vote of a panel of 3 board-certified cardiothoracic specialist radiologists served as reference standard. We compared CheXNeXt's discriminative performance on the validation set to the performance of 9 radiologists using the area under the receiver operating characteristic curve (AUC). The radiologists included 6 board-certified radiologists (average experience 12 years, range 4-28 years) and 3 senior radiology residents, from 3 academic institutions. We found that CheXNeXt achieved radiologist-level performance on 11 pathologies and did not achieve radiologist-level performance on 3 pathologies. The radiologists achieved statistically significantly higher AUC performance on cardiomegaly, emphysema, and hiatal hernia, with AUCs of 0.888 (95% confidence interval [CI] 0.863-0.910), 0.911 (95% CI 0.866-0.947), and 0.985 (95% CI 0.974-0.991), respectively, whereas CheXNeXt's AUCs were 0.831 (95% CI 0.790-0.870), 0.704 (95% CI 0.567-0.833), and 0.851 (95% CI 0.785-0.909), respectively. CheXNeXt performed better than radiologists in detecting atelectasis, with an AUC of 0.862 (95% CI 0.825-0.895), statistically significantly higher than radiologists' AUC of 0.808 (95% CI 0.777-0.838); there were no statistically significant differences in AUCs for the other 10 pathologies. The average time to interpret the 420 images in the validation set was substantially longer for the radiologists (240 minutes) than for CheXNeXt (1.5 minutes). The main limitations of our study are that neither CheXNeXt nor the radiologists were permitted to use patient history or review prior examinations and that evaluation was limited to a dataset from a single institution. CONCLUSIONS: In this study, we developed and validated a deep learning algorithm that classified clinically important abnormalities in chest radiographs at a performance level comparable to practicing radiologists. Once tested prospectively in clinical settings, the algorithm could have the potential to expand patient access to chest radiograph diagnostics.

What Patients Want to Know about Imaging Examinations: A Multiinstitutional U.S. Survey in Adult and Pediatric Teaching Hospitals on Patient Preferences for Receiving Information before Radiologic Examinations.

Purpose To identify what information patients and parents or caregivers found useful before an imaging examination, from whom they preferred to receive information, and how those preferences related to patient-specific variables including demographics and prior radiologic examinations. Materials and Methods A 24-item survey was distributed at three pediatric and three adult hospitals between January and May 2015. The χ2 or Fisher exact test (categorical variables) and one-way analysis of variance or two-sample t test (continuous variables) were used for comparisons. Multivariate logistic regression was used to determine associations between responses and demographics. Results Of 1742 surveys, 1542 (89%) were returned (381 partial, 1161 completed). Mean respondent age was 46.2 years ± 16.8 (standard deviation), with respondents more frequently female (1025 of 1506, 68%) and Caucasian (1132 of 1504, 75%). Overall, 78% (1117 of 1438) reported receiving information about their examination most commonly from the ordering provider (824 of 1292, 64%), who was also the most preferred source (1005 of 1388, 72%). Scheduled magnetic resonance (MR) imaging or nuclear medicine examinations (P < .001 vs other examination types) and increasing education (P = .008) were associated with higher rates of receiving information. Half of respondents (757 of 1452, 52%) sought information themselves. The highest importance scores for pre-examination information (Likert scale ≥4) was most frequently assigned to information on examination preparation and least frequently assigned to whether an alternative radiation-free examination could be used (74% vs 54%; P < .001). Conclusion Delivery of pre-examination information for radiologic examinations is suboptimal, with half of all patients and caregivers seeking information on their own. Ordering providers are the predominant and preferred source of examination-related information, with respondents placing highest importance on information related to examination preparation. © RSNA, 2018 Online supplemental material is available for this article.

Perivascular Epicardial Fat Stranding at Coronary CT Angiography: A Marker of Acute Plaque Rupture and Spontaneous Coronary Artery Dissection.

Purpose To evaluate the frequency and implications of perivascular fat stranding on coronary computed tomography (CT) angiograms obtained for suspected acute coronary syndrome (ACS). Materials and Methods This retrospective registry study was approved by the institutional review board. The authors reviewed the medical records and images of 1403 consecutive patients (796 men, 607 women; mean age, 52.8 years) who underwent coronary CT angiography at the emergency department from February 2012 to March 2016. Fat attenuation, length and number of circumferential quadrants of the affected segment, and attenuation values in the unaffected epicardial and subcutaneous fat were measured. "Cases" were defined as patients with perivascular fat stranding. Patients with significant stenosis but without fat stranding were considered control subjects. Baseline imaging characteristics, ACS frequency, and results of subsequent downstream testing were compared between cases and control subjects by using two-sample t, Mann-Whitney U, and Fisher tests. Results Perivascular fat stranding was seen in 11 subjects, nine with atherosclerotic lesions and two with spontaneous coronary artery dissections, with a mean fat stranding length of 19.2 mm and circumferential extent averaging 2.9 quadrants. The mean attenuation of perivascular fat stranding, normal epicardial fat, and normal subcutaneous fat was 17, -93.2, and -109.3 HU, respectively (P < .001). Significant differences (P < .05) between cases and control subjects included lower Agatston score, presence of wall motion abnormality, and initial elevation of serum troponin level. ACS frequency was 45.4% in cases and 3.8% in control subjects (P = .001). Conclusion Recognition of perivascular fat stranding may be a helpful additional predictor of culprit lesion and marker of risk for ACS in patients with significant stenosis or spontaneous coronary artery dissection. © RSNA, 2018 Online supplemental material is available for this article.

Free-breathing pediatric chest MRI: Performance of self-navigated golden-angle ordered conical ultrashort echo time acquisition.

PURPOSE: To assess the feasibility and performance of conical k-space trajectory free-breathing ultrashort echo time (UTE) chest magnetic resonance imaging (MRI) versus four-dimensional (4D) flow and effects of 50% data subsampling and soft-gated motion correction. MATERIALS AND METHODS: Thirty-two consecutive children who underwent both 4D flow and UTE ferumoxytol-enhanced chest MR (mean age: 5.4 years, range: 6 days to 15.7 years) in one 3T exam were recruited. From UTE k-space data, three image sets were reconstructed: 1) one with all data, 2) one using the first 50% of data, and 3) a final set with soft-gating motion correction, leveraging the signal magnitude immediately after each excitation. Two radiologists in blinded fashion independently scored image quality of anatomical landmarks on a 5-point scale. Ratings were compared using Wilcoxon rank-sum, Wilcoxon signed-ranks, and Kruskal-Wallis tests. Interobserver agreement was assessed with the intraclass correlation coefficient (ICC). RESULTS: For fully sampled UTE, mean scores for all structures were ≥4 (good-excellent). Full UTE surpassed 4D flow for lungs and airways (P < 0.001), with similar pulmonary artery (PA) quality (P = 0.62). 50% subsampling only slightly degraded all landmarks (P < 0.001), as did motion correction. Subsegmental PA visualization was possible in >93% scans for all techniques (P = 0.27). Interobserver agreement was excellent for combined scores (ICC = 0.83). CONCLUSION: High-quality free-breathing conical UTE chest MR is feasible, surpassing 4D flow for lungs and airways, with equivalent PA visualization. Data subsampling only mildly degraded images, favoring lesser scan times. Soft-gating motion correction overall did not improve image quality. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:200-209.

Added Value of Radiologist Consultation for Pediatric Ultrasound: Implementation and Survey Assessment.

OBJECTIVE: The purpose of this study was to determine whether radiologist-parent (guardian) consultation sessions for pediatric ultrasound with immediate disclosure of examination results if desired increases visit satisfaction, decreases anxiety, and increases understanding of the radiologist's role. SUBJECTS AND METHODS: Parents chaperoning any outpatient pediatric ultrasound were eligible and completed surveys before and after ultrasound examinations. Before the second survey, parents met with a pediatric radiologist on a randomized basis but could opt out and request or decline the consultation. Differences in anxiety and understanding of the radiologist's role before and after the examination were compared, and overall visit satisfaction measures were tabulated. RESULTS: Seventy-seven subjects participated, 71 (92%) of whom spoke to a radiologist, mostly on request. In the consultation group, the mean score (1, lowest; 4, highest) for overall experience was 3.8 ± 0.4 (SD), consultation benefit was 3.7 ± 0.6, and radiologist interaction was 3.7 ± 0.6. Demographics were not predictive of satisfaction with statistical significance in a multivariate model. Forty-six of 68 (68%) respondents correctly described the radiologist's role before consultation. The number increased to 60 (88%) after consultation, and the difference was statistically significant (p < 0.001). There was also a statistically significant decrease in mean anxiety score from 2.0 ± 1.0 to 1.5 ± 0.8 after consultation (p < 0.001). Sixty-four of 70 (91%) respondents indicated that they would prefer to speak with a radiologist during every visit. CONCLUSION: Radiologist consultation is well received among parents and associated with decreased anxiety and increased understanding of the radiologist's role. The results of this study support the value of routine radiologist-parent interaction for pediatric ultrasound.

Radiologist compliance with California CT dose reporting requirements: a single-center review of pediatric chest CT.

OBJECTIVE: Effective July 1, 2012, CT dose reporting became mandatory in California. We sought to assess radiologist compliance with this legislation and to determine areas for improvement. MATERIALS AND METHODS: We retrospectively reviewed reports from all chest CT examinations performed at our institution from July 1, 2012, through June 30, 2013, for errors in documentation of volume CT dose index (CTDIvol), dose-length product (DLP), and phantom size. Reports were considered as legally compliant if both CTDIvol and DLP were documented accurately and as institutionally compliant if phantom size was also documented accurately. Additionally, we tracked reports that did not document dose in our standard format (phantom size, CTDIvol for each series, and total DLP). RESULTS: Radiologists omitted CTDIvol, DLP, or both in nine of 664 examinations (1.4%) and inaccurately reported one or both of them in 56 of the remaining 655 examinations (8.5%). Radiologists omitted phantom size in 11 of 664 examinations (1.7%) and inaccurately documented it in 20 of the remaining 653 examinations (3.1%). Of 664 examinations, 599 (90.2%) met legal reporting requirements, and 583 (87.8%) met institutional requirements. In reporting dose, radiologists variably used less decimal precision than available, summed CTDIvol, included only series-level DLP, and specified dose information from the scout topogram or a nonchest series for combination examinations. CONCLUSION: Our institutional processes, which primarily rely on correct human performance, do not ensure accurate dose reporting and are prone to variation in dose reporting format. In view of this finding, we are exploring higher-reliability processes, including better-defined standards and automated dose reporting systems, to improve compliance.