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Background: Gastric fluid volume has been used as a surrogate marker for pulmonary aspiration risk in studies evaluating fasting protocol safety. This study measured residual gastric fluid volume in children using a protocol in which diluted oral contrast medium was administered up until one hour before anesthesia. Methods: This was a single-center prospective observational cohort trial of 70 children for elective abdominal/pelvic computed tomography (CT). Imaging was performed after diluted enteral contrast medium administration, beginning two hours before and ending at least one hour before induction. For each patient, gastric fluid volume was calculated using an image region of interest. The primary outcome measure was gastric fluid volume measured using the computed tomography image. Results: The median time from the end of contrast administration to imaging was 1.5 h (range: 1.1 to 2.2 h). Residual gastric volume, measured using CT was <0.4 mL/Kg in 33%; ≥0.4 mL/Kg in 67%; and ≥1.5 mL/Kg in 44% of patients. Residual gastric volumes measured using CT and aspiration were moderately correlated (Spearman's correlation coefficient = 0.41, p = 0.0003). However, the median residual gastric volume measured using CT (1.17, IQR: 0.22 to 2.38 mL/Kg) was higher than that of aspiration (0.51, IQR: 0 to 1.58 mL/Kg, p = 0.0008 on differences in paired measures). Three cases of vomiting were reported. No evidence of pulmonary aspiration was identified. Conclusions: Children who receive large quantities of clear fluid up to one hour before anesthesia can have a significant gastric residual volume.

Background: In patients with microtia, auricular reconstruction is ideally performed promptly to prevent impaired socialization during formative childhood years. The earliest viable age for reconstruction is widely accepted from 7-10 years of age, as full auricular size is achieved around age 8, with some variability dependent on sex. This retrospective study aims to provide an auricular growth curve that accounts for age and sex, enhancing the individualized approach to ear reconstruction., Methods: A total of 319 images of unaffected patients who underwent computed tomography angiography of the head and neck were reviewed, with bilateral cartilage height and width measured according to a consensus-standardized image measurement protocol. Means and SDs of cartilage height and width were calculated for both sexes, and analysis of ear growth was performed through plotting the mean cartilage height, width, and width:height ratio over time., Results: Cartilage height and width differed significantly between male and female groups. Maximum cartilage height was reached at age 11 for female and at age 12 for male patients, whereas maximum cartilage width was reached at ages 10 and 8, respectively. On average, the width:height ratio for female group was 0.58. For male group, the average width:height ratio was 0.59., Conclusions: An auricular growth map was designed using computed tomography measurements demonstrating maximum auricular size at age 11 and 12 respectively for female and male patients, with both sexes having a width:height ratio maintained at approximately 0.6 throughout growth., Competing Interests: Disclosure statements are at the end of this article, following the correspondence information., (Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)

Tracheomalacia is an airway condition in which the trachea excessively collapses during breathing. Neonates diagnosed with tracheomalacia require more energy to breathe, and the effect of tracheomalacia can be quantified by assessing flow-resistive work of breathing (WOB) in the trachea using computational fluid dynamics (CFD) modeling of the airway. However, CFD simulations are computationally expensive; the ability to instead predict WOB based on more straightforward measures would provide a clinically useful estimate of tracheal disease severity. The objective of this study is to quantify the WOB in the trachea using CFD and identify simple airway and/or clinical parameters that directly relate to WOB. This study included 30 neonatal intensive care unit subjects (15 with tracheomalacia and 15 without tracheomalacia). All subjects were imaged using ultrashort echo time (UTE) MRI. CFD simulations were performed using patient-specific data obtained from MRI (airway anatomy, dynamic motion, and airflow rates) to calculate the WOB in the trachea. Several airway and clinical measurements were obtained and compared with the tracheal resistive WOB. The maximum percent change in the tracheal cross-sectional area (ρ = 0.560, P = 0.001), average glottis cross-sectional area (ρ = -0.488, P = 0.006), minute ventilation (ρ = 0.613, P < 0.001), and lung tidal volume (ρ = 0.599, P < 0.001) had significant correlations with WOB. A multivariable regression model with three independent variables (minute ventilation, average glottis cross-sectional area, and minimum of the eccentricity index of the trachea) can be used to estimate WOB more accurately ( R 2  = 0.726). This statistical model may allow clinicians to estimate tracheal resistive WOB based on airway images and clinical data. NEW & NOTEWORTHY The work of breathing due to resistance in the trachea is an important metric for quantifying the effect of tracheal abnormalities such as tracheomalacia, but currently requires complex dynamic imaging and computational fluid dynamics simulation to calculate it. This study produces a method to predict the tracheal work of breathing based on readily available imaging and clinical metrics.

Background: Repair of pectus excavatum has cosmetic benefits, but the physiologic impact remains controversial. The aim of this study was to characterize the relationship between the degree of pectus excavatum and cardiopulmonary dysfunction seen on cardiac magnetic resonance (CMR) imaging, cardiopulmonary exercise testing (CPET), and pulmonary function testing (PFT)., Methods: A single-center analysis of CMR, CPET, and PFT was conducted. Regression models evaluated relationships between pectus indices and the clinical end points of cardiopulmonary function., Results: Data from 345 CMRs, 261 CPETs, and 281 PFTs were analyzed. Patients were a mean age of 15.2 ± 4 years, and 81% were aged <18 years. The right ventricular ejection fraction (RVEF) was <0.50 in 16% of patients, left ventricular ejection fraction (LVEF) was <0.55 in 22%, RVEF Z-score was < -2 in 32%, and the LVEF Z-score was < -2 in 18%. CPET revealed 33% of patients had reduced aerobic fitness. PFT results were abnormal in 23.1% of patients. Adjusted analyses revealed the Haller index had significant (P < .05) inverse associations with RVEF and LVEF., Conclusions: The severity of pectus excavatum is associated with ventricular systolic dysfunction. Pectus excavatum impacts right and left ventricular systolic function and can also impact exercise tolerance. The Haller index and correction index may be the most useful predictors of impairment., (Copyright © 2022 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

General anesthesia decreases the tone of upper airway muscles in a dose-dependent fashion, potentially narrowing the pharyngeal airway. We examined the effects of adding ketamine on the airway configuration after dexmedetomidine administration in spontaneously breathing children with normal airways. 25 children presenting for Magnetic Resonance Imaging (MRI) of the brain/spine under general anesthesia were prospectively recruited in the study. Patients were anesthetized with dexmedetomidine bolus (2 mcg over 10 min) followed by dexmedetomidine infusion (2 mcg·kg-1·h) and ketamine and permitted to breathe spontaneously via the native airway. MR-CINE images of the upper airway were obtained with dexmedetomidine infusion alone (baseline) and 5, 10, and 15 min after administering ketamine bolus (2 mg·kg-1) in two anatomical axial planes at the nasopharynx and the retroglossal upper airway. Airway lumen is segmented with a semi-automatic image processing approach using a region-growing algorithm. Outcome measures of cross-sectional area, transverse and anterior-posterior diameters of the airway in axial planes at the level of the epiglottis in the retroglossal airway, and in the superior nasopharynx were evaluated for changes in airway size with sedation. Airway dimensions corresponding to the maximum, mean, and minimum sizes during a respiratory cycle were obtained to compare the temporal changes in the airway size. The dose-response of adding ketamine to dexmedetomidine alone condition on airway dimensions were examined using mixed-effects of covariance models. 22/25 patients based on inclusion/exclusion criteria were included in the final analysis. The changes in airway measures with the addition of ketamine, when compared to the baseline of dexmedetomidine alone, were statistically insignificant. The modest changes in airway dimensions are clinically less impactful and within the accuracy of the semi-automatic airway segmentation approach. The effect sizes were small for most airway measures. The duration of ketamine seems to not affect the airway size. In conclusion, adding ketamine to dexmedetomidine did not significantly reduce upper airway configuration when compared to dexmedetomidine alone.

Background: Bronchopulmonary dysplasia (BPD) associated with pulmonary hypertension (PH) is a significant source of morbidity and mortality in premature infants. Recent advances have allowed the use of cardiovascular magnetic resonance (CMR) in the assessment of respiratory and cardiac disease in infants with BPD. In adults and older pediatric patients, decreased CMR interventricular septal curvature correlates with increased mean pulmonary artery pressure and pulmonary vascular resistance. The current study sought to determine the relationship of CMR derived septal curvature in neonates with BPD and BPD-PH with a need for PH therapy., Methods: Forty moderate or severe BPD and 12 mild BPD or control infants were imaged without contrast between 38 and 47 weeks post-menstrual age on a neonatal-sized, neonatal intensive care unit-sited 1.5 T CMR scanner. CMR indices including eccentricity index (CMR-EI) and septal curvature were measured and compared to BPD severity and clinical outcomes including hospital length of stay (LOS), duration of respiratory support, respiratory support level at discharge and PH therapy., Results: CMR-EI was directly associated and septal curvature was inversely associated with BPD severity. In a univariate analysis, CMR-EI and septal curvature were associated with increased hospital LOS, duration of respiratory support, respiratory support at hospital discharge, and need for PH therapy. In multivariable analysis CMR-EI was associated with hospital LOS and duration of respiratory support and septal curvature was associated with respiratory support at hospital discharge. Septal curvature was the only clinical or CMR variable associated with need for PH therapy (R 2  = 0.66, p = 0.0014) in multivariable analysis demonstrating improved discrimination beyond CMR-EI., Conclusions: CMR derived septal curvature correlates significantly with clinical outcomes including hospital LOS, duration of respiratory support, respiratory support level at hospital discharge, and PH therapy in neonates with BPD and BPD-PH. Further, CMR derived septal curvature demonstrated improved discrimination of need for PH therapy and respiratory support at discharge compared to clinical variables and other CMR indices, supporting septal curvature as a non-invasive marker of PH in this population with potential to guide management strategies.

Increased extracellular volume (ECV) by CMR is a marker of interstitial myocardial fibrosis and is associated with diastolic dysfunction in sickle cell anemia (SCA). Left atrial (LA) dysfunction and stiffness contribute to the development of diastolic heart failure in other settings. We aimed to evaluate LA function and stiffness associations with ECV, tricuspid regurgitation jet velocity (TRV) and exercise abnormalities in SCA. In a prospective study, individuals with SCA underwent CMR, echocardiography and exercise test. ECV was measured using MOLLI sequence. Atrial strain was studied in the 4- and 2-chamber views. LA stiffness was calculated as the ratio of echocardiographic E/e'-to-LA reservoir strain. Twenty-four participants with SCA were included (median age 20 years). ECV was increased in participant with SCA compared to our lab normal values (mean 0.44 ± 0.08 vs 0.26 ± 0.02, P < 0.0001). Six (25%) had LA LGE. ECV positively correlated with LA stiffness (r = 0.45, p = 0.04). There was a negative correlation between LA stiffness and %predicted VO2 (r = -0.50, p = 0.04). LA stiffness was moderately associated with increased TRV (r = 0.55, p < 0.005). LA stiffness is associated with ECV, exercise impairment and increased TRV. This study sheds insights on the interaction between LA function, RV hypertension, and myocardial fibrosis in SCA.

Background: Cardiovascular magnetic resonance (CMR) angiography (CMRA) is an important non-invasive imaging tool for congenital heart disease (CHD) and aortopathy patients. The conventional 3D balanced steady-state free precession (bSSFP) sequence is often confounded by imaging artifacts. We sought to compare the respiratory navigated and electrocardiogram (ECG) gated modified Dixon (mDixon) CMRA sequence to conventional non-gated dynamic multi-phase contrast enhanced CMRA (CE-CMRA) and bSSFP across a variety of diagnoses., Methods: We included 24 patients with CHD or aortopathy with CMR performed between September 2017 to December 2017. Each patient had undergone CE-CMRA, followed by a bSSFP and mDixon angiogram. Patients with CMR-incompatible implants or contraindications to contrast were excluded. The studies were rated according to image quality at a scale from 1 (poor) to 4 (excellent) based on diagnostic adequacy, artifact burden, vascular border delineation, myocardium-blood pool contrast, and visualization of pulmonary and systemic veins and coronaries. Contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and quantitative vascular measurements were compared between the two gated sequences. Bland-Altman plots were generated to compare paired measures., Results: All scans were diagnostically adequate. Mean (SD) quality scores were 3.4 (0.7) for the mDixon, 3.2 (0.5) for the bSSFP and 3.4 (0.5) for the CE-CMRA. Qualitatively, the intracardiac anatomy and myocardium-blood pool definition were better in the bSSFP; however, mDixon images showed enhanced vessel wall sharpness with less blurring surrounding the anatomical borders distally. Coronary origins were identified in all cases. Pulmonary veins were visualized in 92% of mDixon sequences, 75% of bSSFP and 96% of CE-CMRA. Similarly, neck veins were identified in 92, 83 and 96% respectively. Artifacts prevented vascular measurement in 6/192 (3%) and 4/192 (2%) of total vascular measurements for the mDixon and bSSFP, respectively. However, the size of signal void and field distortion were significantly worse in the latter, particularly for flow and metal induced artifacts., Conclusion: In patients with congenital heart disease, ECG gated mDixon angiography yields high fidelity vascular images including better delineation of head and neck vasculature and pulmonary veins and fewer artifacts than the comparable bSSFP sequence. It should be considered as the preferred strategy for successful CHD imaging in patients with valve stenosis, vascular stents, or metallic implants.

Rationale: Bronchopulmonary dysplasia (BPD) is a serious neonatal pulmonary condition associated with premature birth, but the underlying parenchymal disease and trajectory are poorly characterized. The current National Institute of Child Health and Human Development (NICHD)/NHLBI definition of BPD severity is based on degree of prematurity and extent of oxygen requirement. However, no clear link exists between initial diagnosis and clinical outcomes., Objectives: We hypothesized that magnetic resonance imaging (MRI) of structural parenchymal abnormalities will correlate with NICHD-defined BPD disease severity and predict short-term respiratory outcomes., Methods: A total of 42 neonates (20 severe BPD, 6 moderate, 7 mild, 9 non-BPD control subjects; 40 ± 3-wk postmenstrual age) underwent quiet-breathing structural pulmonary MRI (ultrashort echo time and gradient echo) in a neonatal ICU-sited, neonatal-sized 1.5 T scanner, without sedation or respiratory support unless already clinically prescribed. Disease severity was scored independently by two radiologists. Mean scores were compared with clinical severity and short-term respiratory outcomes. Outcomes were predicted using univariate and multivariable models, including clinical data and scores., Measurements and Main Results: MRI scores significantly correlated with severities and predicted respiratory support at neonatal ICU discharge (P < 0.0001). In multivariable models, MRI scores were by far the strongest predictor of respiratory support duration over clinical data, including birth weight and gestational age. Notably, NICHD severity level was not predictive of discharge support., Conclusions: Quiet-breathing neonatal pulmonary MRI can independently assess structural abnormalities of BPD, describe disease severity, and predict short-term outcomes more accurately than any individual standard clinical measure. Importantly, this nonionizing technique can be implemented to phenotype disease, and has potential to serially assess efficacy of individualized therapies.

Esophageal atresia (EA) is a relatively uncommon congenital anomaly, often observed in conjunction with tracheoesophageal fistula (TEF). Surgical repair in neonates typically takes place with little information about the pre-existing EA/TEF structure because there are currently no acceptable tools for evaluating EA/TEF anatomy prior to repair; chest x-ray radiograph does not identify malformation sub-type or gap length, while x-ray computed tomography (CT) demonstrate an unacceptably high exposure to ionizing radiation. There is a need for safe imaging methods to evaluate pre-operative EA/TEF anatomy, which would add value in surgical planning; this need may be met with high-resolution structural MRI. We report three cases of Type-C EA/TEF in neonates. Patients were imaged prior to surgical repair using high-resolution ultrashort echo time (UTE) magnetic resonance imaging (MRI) to visualize tracheoesophageal anatomy and allow for informed surgical planning and risk management. One of the three patients was imaged post-repair to evaluate surgical efficacy and evolution of the tracheoesophageal anatomy.

Study Objectives: To describe a dynamic three-dimensional (3D) computed tomography (CT) technique for the upper airway and compare the required radiation dose to that used for common clinical studies of a similar anatomical area, such as for subjects undergoing routine clinical facial CT., Methods: Dynamic upper-airway CT was performed on eight subjects with persistent obstructive sleep apnea, four of whom were undergoing magnetic resonance imaging and an additional four subjects who had a contraindication to magnetic resonance imaging. This Health Insurance Portability and Accountability Act-compliant study was approved by our institutional review board, and informed consent was obtained. The control subjects (n = 41) for comparison of radiation dose were obtained from a retrospective review of the clinical picture-archiving computer system to identify 10 age-matched patients per age-based control group undergoing facial CT., Results: Dynamic 3D CT can be performed with an effective radiation dose of less than 0.38 mSv, a dose that is less than or comparable to that used for clinical facial CT. The resulting data- set is a uniquely complete, dynamic 3D volume of the upper airway through a full respiratory cycle that can be processed for clinical and modeling analyses., Conclusions: A dynamic 3D CT technique of the upper airway is described that can be performed with a clinically reasonable radiation dose and sets a benchmark for future use., (© 2017 American Academy of Sleep Medicine)

Rationale: Bronchopulmonary dysplasia (BPD) is a prevalent yet poorly characterized pulmonary complication of premature birth; the current definition is based solely on oxygen dependence at 36 weeks postmenstrual age without objective measurements of structural abnormalities across disease severity., Objectives: We hypothesize that magnetic resonance imaging (MRI) can spatially resolve and quantify the structural abnormalities of the neonatal lung parenchyma associated with premature birth., Methods: Using a unique, small-footprint, 1.5-T MRI scanner within our neonatal intensive care unit (NICU), diagnostic-quality MRIs using commercially available sequences (gradient echo and spin echo) were acquired during quiet breathing in six patients with BPD, six premature patients without diagnosed BPD, and six full-term NICU patients (gestational ages, 23-39 wk) at near term-equivalent age, without administration of sedation or intravenous contrast. Images were scored by a radiologist using a modified Ochiai score, and volumes of high- and low-signal intensity lung parenchyma were quantified by segmentation and threshold analysis., Measurements and Main Results: Signal increases, putatively combinations of fibrosis, edema, and atelectasis, were present in all premature infants. Infants with diagnosed BPD had significantly greater volume of high-signal lung (mean ± SD, 26.1 ± 13.8%) compared with full-term infants (7.3 ± 8.2%; P = 0.020) and premature infants without BPD (8.2 ± 6.4%; P = 0.026). Signal decreases, presumably alveolar simplification, only appeared in the most severe BPD cases, although cystic appearance did increase with severity., Conclusions: Pulmonary MRI reveals quantifiable, significant differences between patients with BPD, premature patients without BPD, and full-term control subjects. These methods could be implemented to individually phenotype disease, which may impact clinical care and predict future outcomes.

Background: Patients with Duchenne muscular dystrophy exhibit progressive cardiac and skeletal muscle dysfunction. Based on prior data, cardiac dysfunction in Duchenne muscular dystrophy patients may be influenced by myocardial fibrosis and steroid therapy. We examined the longitudinal relationship of myocardial fibrosis and ventricular dysfunction using cardiac magnetic resonance in a large Duchenne muscular dystrophy cohort., Methods and Results: We reviewed 465 serial cardiac magnetic resonance studies (98 Duchenne muscular dystrophy patients with ≥4 cardiac magnetic resonance studies) for left ventricular ejection fraction (LVEF) and presence of late gadolinium enhancement (LGE), a marker for myocardial fibrosis. LVEF was modeled by examining LGE status, myocardial fibrosis burden (as assessed by the number of LGE-positive left ventricular segments), patient age, and steroid treatment duration. An age-only model demonstrated that LVEF declined 0.58 ± 0.10% per year. In patients with both LGE-negative and LGE-positive studies (n=51), LVEF did not decline significantly over time if LGE was absent but declined 2.2 ± 0.31% per year when LGE was present. Univariate modeling showed significant associations between LVEF and steroid treatment duration, presence of LGE, and number of LGE-positive left ventricular segments; multivariate modeling showed that LVEF declined by 0.93 ± 0.09% for each LGE-positive left ventricular segment, whereas age and steroid treatment duration were not significant. The number of LGE-positive left ventricular segments increased with age, and longer steroid treatment duration was associated with lower age-related increases., Conclusion: Progressive myocardial fibrosis, as detected by LGE, was strongly correlated with the LVEF decline in Duchenne muscular dystrophy patients. Longer steroid treatment duration was associated with a lower age-related increase in myocardial fibrosis burden., (© 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)

Paleomagnetic and (40)Ar/(39)Ar analyses from the Lathrop Wells volcanic center, Nevada, indicate that two eruptive events have occurred there. The ages (136 +/- 8 and 141 +/- 9 thousand years ago) for these two events are analytically indistinguishable. The small angular difference (4.7 degrees ) between the paleomagnetic directions from these two events suggests they differ in age by only about 100 years. These ages are consistent with the chronology of the surficial geological units in the Yucca Mountain area. These results contradict earlier interpretations of the cinder-cone geomorphology and soil-profile data that suggest that at least five temporally discrete eruptive events occurred at Lathrop Wells approximately 20,000 years ago.