Impact of ferumoxytol vs gadolinium on 4D flow cardiovascular magnetic resonance measurements in small children with congenital heart disease.

BACKGROUND: Cardiovascular magnetic resonance (CMR) allows for time-resolved three-dimensional phase-contrast (4D Flow) analysis of congenital heart disease (CHD). Higher spatial resolution in small infants requires thinner slices, which can degrade the signal. Particularly in infants, the choice of contrast agent (ferumoxytol vs. gadolinium) may influence 4D Flow CMR accuracy. Thus, we investigated the accuracy of 4D Flow CMR measurements compared to gold standard 2D flow phase contrast (PC) measurements in ferumoxytol vs. gadolinium-enhanced CMR of small CHD patients with shunt lesions. METHODS: This was a retrospective study consisting of CMR studies from complex CHD patients less than 20 kg who had ferumoxytol or gadolinium-enhanced 4D Flow and standard two-dimensional phase contrast (2D-PC) flow collected. 4D Flow clinical software (Arterys) was used to measure flow in great vessels, systemic veins, and pulmonary veins. 4D Flow accuracy was defined as percent difference or correlation against conventional measurements (2D-PC) from the same vessels. Subgroup analysis was performed on two-ventricular vs single-ventricular CHD, arterial vs venous flow, as well as low flows (defined as < 1.5 L/min) in 1V CHD. RESULTS: Twenty-one ferumoxytol-enhanced and 23 gadolinium-enhanced CMR studies were included, with no difference in age (2.1 ± 1.6 vs. 2.3 ± 1.9 years, p = 0.70), patient body surface area (0.50 ± 0.2 vs. 0.52 ± 0.2 m2, p = 0.67), or vessel diameter (11.4 ± 5.2 vs. 12.4 ± 5.6 mm, p = 0.22). Ten CMR studies with single ventricular CHD were included. Overall, ferumoxytol-enhanced 4D flow CMR measurements demonstrated less percent difference to 2D-PC when compared to gadolinium-enhanced 4D Flow CMR studies. In subgroup analyses of arterial vs. venous flows (high velocity vs. low velocity) and low flow in single ventricle CHD, ferumoxytol-enhanced 4D Flow CMR measurements had stronger correlation to 2D-PC CMR. The contrast-to-noise ratio (CNR) in ferumoxytol-enhanced studies was higher than the CNR in gadolinium-enhanced studies. CONCLUSIONS: Ferumoxytol-enhanced 4D Flow CMR has improved accuracy when compared to gadolinium 4D Flow CMR, particularly for infants with small vessels in CHD.

Cardiac echocardiogram findings of severe acute respiratory syndrome coronavirus-2-associated multi-system inflammatory syndrome in children.

BACKGROUND: A novel paediatric disease, multi-system inflammatory syndrome in children, has emerged during the 2019 coronavirus disease pandemic. OBJECTIVES: To describe the short-term evolution of cardiac complications and associated risk factors in patients with multi-system inflammatory syndrome in children. METHODS: Retrospective single-centre study of confirmed multi-system inflammatory syndrome in children treated from 29 March, 2020 to 1 September, 2020. Cardiac complications during the acute phase were defined as decreased systolic function, coronary artery abnormalities, pericardial effusion, or mitral and/or tricuspid valve regurgitation. Patients with or without cardiac complications were compared with chi-square, Fisher's exact, and Wilcoxon rank sum. RESULTS: Thirty-nine children with median (interquartile range) age 7.8 (3.6-12.7) years were included. Nineteen (49%) patients developed cardiac complications including systolic dysfunction (33%), valvular regurgitation (31%), coronary artery abnormalities (18%), and pericardial effusion (5%). At the time of the most recent follow-up, at a median (interquartile range) of 49 (26-61) days, cardiac complications resolved in 16/19 (84%) patients. Two patients had persistent mild systolic dysfunction and one patient had persistent coronary artery abnormality. Children with cardiac complications were more likely to have higher N-terminal B-type natriuretic peptide (p = 0.01), higher white blood cell count (p = 0.01), higher neutrophil count (p = 0.02), severe lymphopenia (p = 0.05), use of milrinone (p = 0.03), and intensive care requirement (p = 0.04). CONCLUSION: Patients with multi-system inflammatory syndrome in children had a high rate of cardiac complications in the acute phase, with associated inflammatory markers. Although cardiac complications resolved in 84% of patients, further long-term studies are needed to assess if the cardiac abnormalities (transient or persistent) are associated with major cardiac events.

Motion-corrected cardiac MRI is associated with decreased anesthesia exposure in children.

BACKGROUND: The benefits of cardiac magnetic resonance imaging (MRI) in the pediatric population must be balanced with the risk and cost of anesthesia. Segmented imaging using multiple averages attempts to avoid breath-holds requiring general anesthesia; however, cardiorespiratory artifacts and prolonged scan times limit its use. Thus, breath-held imaging with general anesthesia is used in many pediatric centers. The advent of free-breathing, motion-corrected (MOCO) cines by real-time re-binned reconstruction offers reduced anesthesia exposure without compromising image quality. OBJECTIVE: This study evaluates sedation utilization in our pediatric cardiac MR practice before and after clinical introduction of free-breathing MOCO imaging for cine and late gadolinium enhancement. MATERIALS AND METHODS: In a retrospective study, patients referred for a clinical cardiac MR who would typically be offered sedation for their scan (n=295) were identified and divided into two eras, those scanned before the introduction of MOCO cine and late gadolinium enhancement sequences and those scanned following their introduction. Anesthesia use was compared across eras and disease-specific cohorts. RESULTS: The incidence of non-sedation studies performed in children nearly tripled following the introduction of MOCO imaging (25% [pre-MOCO] to 69% [post-MOCO], P<0.01), with the greatest effect in patients with simple congenital heart disease. Eleven percent of the post-MOCO cohort comprised infants younger than 3 months of age who could forgo sedation with the combination of MOCO imaging and a "feed-and-bundle" positioning technique. CONCLUSION: Implementation of cardiac MR with MOCO cine and late gadolinium enhancement imaging in a pediatric population is associated with significantly decreased sedation utilization.

X-ray fused with MRI guidance of pre-selected transcatheter congenital heart disease interventions.

OBJECTIVES: To determine whether X-ray fused with MRI (XFM) is beneficial for select transcatheter congenital heart disease interventions. BACKGROUND: Complex transcatheter interventions often require three-dimensional (3D) soft tissue imaging guidance. Fusion imaging with live X-ray fluoroscopy can potentially improve and simplify procedures. METHODS: Patients referred for select congenital heart disease interventions were prospectively enrolled. Cardiac MRI data was overlaid on live fluoroscopy for procedural guidance. Likert scale operator assessments of value were recorded. Fluoroscopy time, radiation exposure, contrast dose, and procedure time were compared to matched cases from our institutional experience. RESULTS: Forty-six patients were enrolled. Pre-catheterization, same day cardiac MRI findings indicated intervention should be deferred in nine patients. XFM-guided cardiac catheterization was performed in 37 (median age 8.7 years [0.5-63 years]; median weight 28 kg [5.6-110 kg]) with the following prespecified indications: pulmonary artery (PA) stenosis (n = 13), aortic coarctation (n = 12), conduit stenosis/insufficiency (n = 9), and ventricular septal defect (n = 3). Diagnostic catheterization showed intervention was not indicated in 12 additional cases. XFM-guided intervention was performed in the remaining 25. Fluoroscopy time was shorter for XFM-guided intervention cases compared to matched controls. There was no significant difference in radiation dose area product, contrast volume, or procedure time. Operator Likert scores indicated XFM provided useful soft tissue guidance in all cases and was never misleading. CONCLUSIONS: XFM provides operators with meaningful three-dimensional soft tissue data and reduces fluoroscopy time in select congenital heart disease interventions.

Anesthetic considerations for magnetic resonance imaging-guided right-heart catheterization in pediatric patients: A single institution experience.

Cardiac catheterization is an integral part of medical management for pediatric patients with congenital heart disease. Owing to age and lack of cooperation in children who need this procedure, general anesthesia is typically required. These patients have increased anesthesia risk secondary to cardiac pathology. Furthermore, multiple catheterization procedures result in exposure to harmful ionizing radiation. Magnetic resonance imaging-guided right-heart catheterization offers decreased radiation exposure and diagnostic imaging benefits over traditional fluoroscopy but potentially increases anesthetic complexity and risk. We describe our early experience with anesthetic techniques and challenges for pediatric magnetic resonance imaging-guided right-heart catheterization.

Validation of cardiac magnetic-resonance-derived left ventricular strain measurements from free-breathing motion-corrected cine imaging.

BACKGROUND: Myocardial strain is an important measure of cardiac function and can be assessed on cardiac magnetic resonance (MR) through the current gold standard of breath-held segmented steady-state free precession (SSFP) cine imaging. Novel free-breathing techniques have been validated for volumetry and systolic function, allowing for evaluation of sicker and younger children who cannot reliably hold their breath. It is unclear whether strain measurements can be reliably performed on free-breathing, motion-corrected, re-binning cine images. OBJECTIVE: To compare strain analysis from motion-corrected retrospective re-binning images to the breath-held SSFP cine images to explore their validity. MATERIALS AND METHODS: Twenty-five children and young adults, ages (2.1-18.6 years) underwent breath-held and motion-corrected retrospective re-binning cine techniques during the same MR examination on a 1.5-tesla magnet. We measured endocardial end-systolic global circumferential strain and endocardial averaged segmental strain using commercial software (MEDIS QStrain 2.1). We used Pearson correlation coefficients to test agreement across techniques. RESULTS: Analysis was possible in all 25 breath-held and motion-corrected retrospective re-binning studies. Global circumferential strain and endocardial averaged segmental strain obtained by motion-corrected retrospective re-binning compared favorably to breath-held studies. Global circumferential strain linear regression models demonstrated acceptable agreement, with coefficients of determination of 0.75 for breath-held compared to motion-corrected retrospective re-binning (P<0.001) and for endocardial averaged segmental strain comparisons yielded 0.77 for breath-held vs. motion-corrected retrospective re-binning (P<0.001). Bland-Altman assessment demonstrated minimal bias for breath-held compared to motion-corrected retrospective re-binning (mean 2.4 and 1.9, respectively, for global circumferential strain and endocardial averaged segmental strain). CONCLUSION: Free-breathing imaging by motion-corrected retrospective re-binning cine imaging provides adequate spatial and temporal resolution to measure myocardial deformation when compared to the gold-standard breath-held SSFP cine imaging in children with normal or borderline systolic function.

Updates in Congenital Heart Disease: Can Outcomes Improve?

Despite numerous advances in medical and surgical management, congenital heart disease (CHD) remains the number one cause of death in the first year of life from congenital malformations. The current strategies used to approach improving outcomes in CHD are varied. This article will discuss the recent impact of pulse oximetry screening for critical CHD, describe the contributions of advanced cardiac imaging in the neonate with CHD, and highlight the growing importance of quality improvement and safety programs in the cardiac intensive care unit.

Asymptomatic atresia of the anomalous pulmonary vein in a patient with scimitar syndrome presenting in childhood.

An asymptomatic 6-year-old boy with a history of right lung hypoplasia was referred for cardiology evaluation. Echocardiography demonstrated right pulmonary artery hypoplasia with flow reversal in that vessel. The right pulmonary veins were not visualised in the echocardiogram. Cardiac catheterisation confirmed the diagnosis of scimitar syndrome with a characteristic large vertical vein; however, the right pulmonary veins were found to be atretic with no connection to the heart with decompression through the azygos vein. In all, four systemic to pulmonary arterial collaterals were identified, supplying the right lung, which were occluded using embolization coils. This case demonstrates the potential for progressive stenosis and atresia of the so-called "scimitar vein" without previous surgical instrumentation, and that this can occur without haemodynamic embarrassment or development of pulmonary vascular disease.

Acute Cardiac MRI Assessment of Radiofrequency Ablation Lesions for Pediatric Ventricular Arrhythmia: Feasibility and Clinical Correlation.

BACKGROUND: Arrhythmia ablation with current techniques is not universally successful. Inadequate ablation lesion formation may be responsible for some arrhythmia recurrences. Periprocedural visualization of ablation lesions may identify inadequate lesions and gaps to guide further ablation and reduce risk of arrhythmia recurrence. METHODS: This feasibility study assessed acute postprocedure ablation lesions by MRI, and correlated these findings with clinical outcomes. Ten pediatric patients who underwent ventricular tachycardia ablation were transferred immediately postablation to a 1.5T MRI scanner and late gadolinium enhancement (LGE) imaging was performed to characterize ablation lesions. Immediate and mid-term arrhythmia recurrences were assessed. RESULTS: Patient characteristics include median age 14 years (1-18 years), median weight 52 kg (11-81 kg), normal cardiac anatomy (n = 6), d-transposition of great arteries post arterial switch repair (n = 2), anomalous coronary artery origin post repair (n = 1), and cardiac rhabdomyoma (n = 1). All patients underwent radiofrequency catheter ablation of ventricular arrhythmia with acute procedural success. LGE was identified at the reported ablation site in 9/10 patients, all arrhythmia-free at median 7 months follow-up. LGE was not visible in 1 patient who had recurrence of frequent premature ventricular contractions within 2 hours, confirmed on Holter at 1 and 21 months post procedure. CONCLUSIONS: Ventricular ablation lesion visibility by MRI in the acute post procedure setting is feasible. Lesions identifiable with MRI may correlate with clinical outcomes. Acute MRI identification of gaps or inadequate lesions may provide the unique temporal opportunity for additional ablation therapy to decrease arrhythmia recurrence.

Radiation-free CMR diagnostic heart catheterization in children.

BACKGROUND: Children with heart disease may require repeated X-Ray cardiac catheterization procedures, are more radiosensitive, and more likely to survive to experience oncologic risks of medical radiation. Cardiovascular magnetic resonance (CMR) is radiation-free and offers information about structure, function, and perfusion but not hemodynamics. We intend to perform complete radiation-free diagnostic right heart catheterization entirely using CMR fluoroscopy guidance in an unselected cohort of pediatric patients; we report the feasibility and safety. METHODS: We performed 50 CMR fluoroscopy guided comprehensive transfemoral right heart catheterizations in 39 pediatric (12.7 ± 4.7 years) subjects referred for clinically indicated cardiac catheterization. CMR guided catheterizations were assessed by completion (success/failure), procedure time, and safety events (catheterization, anesthesia). Pre and post CMR body temperature was recorded. Concurrent invasive hemodynamic and diagnostic CMR data were collected. RESULTS: During a twenty-two month period (3/2015 - 12/2016), enrolled subjects had the following clinical indications: post-heart transplant 33%, shunt 28%, pulmonary hypertension 18%, cardiomyopathy 15%, valvular heart disease 3%, and other 3%. Radiation-free CMR guided right heart catheterization attempts were all successful using passive catheters. In two subjects with septal defects, right and left heart catheterization were performed. There were no complications. One subject had six such procedures. Most subjects (51%) had undergone multiple (5.5 ± 5) previous X-Ray cardiac catheterizations. Retained thoracic surgical or transcatheter implants (36%) did not preclude successful CMR fluoroscopy heart catheterization. During the procedure, two subjects were receiving vasopressor infusions at baseline because of poor cardiac function, and in ten procedures, multiple hemodynamic conditions were tested. CONCLUSIONS: Comprehensive CMR fluoroscopy guided right heart catheterization was feasible and safe in this small cohort of pediatric subjects. This includes subjects with previous metallic implants, those requiring continuous vasopressor medication infusions, and those requiring pharmacologic provocation. Children requiring multiple, serial X-Ray cardiac catheterizations may benefit most from radiation sparing. This is a step toward wholly CMR guided diagnostic (right and left heart) cardiac catheterization and future CMR guided cardiac intervention. TRIAL REGISTRATION: ClinicalTrials.gov NCT02739087 registered February 17, 2016.

Native T1 values identify myocardial changes and stratify disease severity in patients with Duchenne muscular dystrophy.

BACKGROUND: Duchenne muscular dystrophy (DMD) is an X-linked, inherited disorder causing dilated cardiomyopathy with variable onset and progression. Currently we lack objective markers of the effect of therapies targeted towards preventing progression of subclinical cardiac disease. Thus, our aim was to compare the ability of native T1 and extracellular volume (ECV) measurements to differentiate risk of myocardial disease in DMD and controls. METHODS: Twenty boys with DMD and 16 age/gender-matched controls without history predisposing to cardiac fibrosis, but with a clinical indication for cardiovascular magnetic resonance (CMR) evaluation, underwent CMR with contrast. Data points collected include left ventricular ejection fraction (LVEF), left ventricular mass, and presence of late gadolinium enhancement (LGE). Native T1, and ECV regional mapping were obtained using both a modified Look-Locker (MOLLI) and saturation recovery single shot sequence (SASHA) on a 1.5T scanner. Using ordinal logistic regression models, controlling for age and LVEF, LGE-free septal we evaluated the ability native T1 and ECV assessments to differentiate levels of cardiomyopathy. RESULTS: Twenty DMD subjects aged 14.4 ± 4 years had an LVEF of 56.3 ± 7.4 %; 12/20 had LGE, all confined to the lateral wall. Sixteen controls aged 16.1 ± 2.2 years had an LVEF 60.4 ± 5.1 % and no LGE. Native T1 and ECV values were significantly higher in the DMD group (p < 0.05) with both MOLLI and SASHA imaging techniques. Native T1 demonstrated a 50 % increase in the ability to predict disease state (control, DMD without fibrosis, DMD with fibrosis). ECV demonstrated only the ability to predict presence of LGE, but could not distinguish between controls and DMD without fibrosis. CONCLUSIONS: LGE-spared regions of boys with DMD have significantly different native T1 and ECV values compared to controls. Native T1 measurements can identify early changes in DMD patients without the presence of LGE and help predict disease severity more effectively than ECV. Native T1 may be a novel outcome measure for early cardiac therapies in DMD and other cardiomyopathies.

Dark blood late enhancement imaging.

BACKGROUND: Bright blood late gadolinium enhancement (LGE) imaging typically achieves excellent contrast between infarcted and normal myocardium. However, the contrast between the myocardial infarction (MI) and the blood pool is frequently suboptimal. A large fraction of infarctions caused by coronary artery disease are sub-endocardial and thus adjacent to the blood pool. It is not infrequent that sub-endocardial MIs are difficult to detect or clearly delineate. METHODS: In this present work, an inversion recovery (IR) T2 preparation was combined with single shot steady state free precession imaging and respiratory motion corrected averaging to achieve dark blood LGE images with good signal to noise ratio while maintaining the desired spatial and temporal resolution. In this manner, imaging was conducted free-breathing, which has benefits for image quality, patient comfort, and clinical workflow in both adults and children. Furthermore, by using a phase sensitive inversion recovery reconstruction the blood signal may be made darker than the myocardium (i.e., negative signal values) thereby providing contrast between the blood and both the MI and remote myocardium. In the proposed approach, a single T1-map scout was used to measure the myocardial and blood T1 using a MOdified Look-Locker Inversion recovery (MOLLI) protocol and all protocol parameters were automatically calculated from these values within the sequence thereby simplifying the user interface. RESULTS: The contrast to noise ratio (CNR) between MI and remote myocardium was measured in n = 30 subjects with subendocardial MI using both bright blood and dark blood protocols. The CNR for the dark blood protocol had a 13 % loss compared to the bright blood protocol. The CNR between the MI and blood pool was positive for all dark blood cases, and was negative in 63 % of the bright blood cases. The conspicuity of subendocardial fibrosis and MI was greatly improved by dark blood (DB) PSIR as well as the delineation of the subendocardial border. CONCLUSIONS: Free-breathing, dark blood PSIR LGE imaging was demonstrated to improve the visualization of subendocardial MI and fibrosis in cases with low contrast with adjacent blood pool. The proposed method also improves visualization of thin walled fibrous structures such as atrial walls and valves, as well as papillary muscles.

The Impact of a Designated Cardiology Team Involving Telemedicine Home Monitoring on the Care of Children with Single-Ventricle Physiology After Norwood Palliation.

We evaluated the effect of an interdisciplinary single-ventricle task force (SVTF) that utilizes a family-driven, telemedicine home monitoring program on clinical outcomes of stage II admissions and its acceptance by parents and cardiologists. Study population was divided into two cohorts, one with Norwood surgery dates before the SVTF (pre-SVTF) and one interventional (post-SVTF). Post-SVTF data also included surveys of parents and cardiologists on the efficacy of the SVTF. Comparative and multivariate statistical testing was performed. Compared to the pre-SVTF group, the post-SVTF group had lower complications after stage II (18.4 vs. 34.1 %, p = 0.02), higher weight-for-age z scores at stage II (-1.5 ± 0.97 vs. -1.58 ± 1.34, p = 0.02) and were less likely to have a stage II weight-for-age z score below -2 (26.5 vs. 31.7 %, p = 0.03). A multivariate regression analysis showed providing a written red-flag action plan to parents at discharge was independently associated with higher weight at stage II (ß = 0.42, p = 0.04) and higher weight-for-age z score (ß = 0.48, p = 0.02). Parents' satisfaction with SVTF (α = 0.97) was 4.34 ± 0.62; (95 % CI 4.01-4.67) and cardiologists' acceptance (α = 0.93) was 4.1 ± 0.7 (95 % CI 3.79-4.42). Development of SVTF was associated with a reduction in complications post-stage II and improved weight status at stage II. A written red-flag action plan provided to parents at the time of Norwood discharge was associated with higher weight status at stage II. Parents and cardiologists expressed satisfaction with the utility of SVTF and encouraged expansion to cover all children with congenital heart disease.

Optimized protocols for cardiac magnetic resonance imaging in patients with thoracic metallic implants.

BACKGROUND: Cardiac magnetic resonance (MR) imaging is a valuable tool in congenital heart disease; however patients frequently have metal devices in the chest from the treatment of their disease that complicate imaging. Methods are needed to improve imaging around metal implants near the heart. Basic sequence parameter manipulations have the potential to minimize artifact while limiting effects on image resolution and quality. OBJECTIVE: Our objective was to design cine and static cardiac imaging sequences to minimize metal artifact while maintaining image quality. MATERIALS AND METHODS: Using systematic variation of standard imaging parameters on a fluid-filled phantom containing commonly used metal cardiac devices, we developed optimized sequences for steady-state free precession (SSFP), gradient recalled echo (GRE) cine imaging, and turbo spin-echo (TSE) black-blood imaging. We imaged 17 consecutive patients undergoing routine cardiac MR with 25 metal implants of various origins using both standard and optimized imaging protocols for a given slice position. We rated images for quality and metal artifact size by measuring metal artifact in two orthogonal planes within the image. RESULTS: All metal artifacts were reduced with optimized imaging. The average metal artifact reduction for the optimized SSFP cine was 1.5+/-1.8 mm, and for the optimized GRE cine the reduction was 4.6+/-4.5 mm (P < 0.05). Quality ratings favored the optimized GRE cine. Similarly, the average metal artifact reduction for the optimized TSE images was 1.6+/-1.7 mm (P < 0.05), and quality ratings favored the optimized TSE imaging. CONCLUSION: Imaging sequences tailored to minimize metal artifact are easily created by modifying basic sequence parameters, and images are superior to standard imaging sequences in both quality and artifact size. Specifically, for optimized cine imaging a GRE sequence should be used with settings that favor short echo time, i.e. flow compensation off, weak asymmetrical echo and a relatively high receiver bandwidth. For static black-blood imaging, a TSE sequence should be used with fat saturation turned off and high receiver bandwidth.

Mesalamine-induced myopericarditis in a paediatric patient with Crohn's disease.

Mesalamine-containing products are considered first-line treatment for inflammatory bowel disease. Myocarditis is recognised as a very rare possible side effect of these medications, but has not often been described in the paediatric population. We present a case of an adolescent with Crohn's disease who presented with myopericarditis after recent initiation of Pentasa. Once identified as the causative agent, the drug was discontinued, with subsequent normalisation of troponin and improvement of function. This case identifies the importance of prompt evaluation, diagnosis, and treatment of paediatric patients receiving mesalamine-containing medications that present with significant cardiovascular symptoms.

Method for calculating confidence intervals for phase contrast flow measurements.

BACKGROUND: Phase contrast (PC) measurements play an important role in several cardiovascular magnetic resonance (CMR) protocols but considerable variation is observed in such measurements. Part of this variation stems from the propagation of thermal noise from the measurement data through the image reconstruction to the region of interest analysis used in flow measurement, which limits the precision. The purpose of this study was to develop a method for direct estimation of the variation caused by thermal noise and to validate this method in phantom and in vivo data. METHODS: The estimation of confidence intervals in flow measurements is complicated by noise correlation among the image pixels and cardiac phases. This correlation is caused by sequence and reconstruction parameters. A method for the calculation of the standard deviation of region of interest measurements was adapted and expanded to accommodate typical clinical PC measurements and the region-of-interest analysis used for such measurements. This included the dependency between cardiac phases that arises due to retrospective cardiac gating used in such studies. The proposed method enables calculation of standard deviations of flow measurements without the need for repeated experiments or repeated reconstructions. The method was compared to repeated trials in phantom measurements and pseudo replica reconstructions of in vivo data. Three different flow protocols (free breathing and breath hold with various accelerations) were compared in terms of the confidence interval ranges caused by thermal noise in the measurement data. RESULTS: Using the proposed method it was possible to accurately predict confidence intervals for flow measurements. The method was in good agreement with repeated measurements in phantom experiments and there was also good agreement with confidence intervals predicted by pseudo replica reconstructions in both phantom and in vivo data. The proposed method was used to demonstrate that the variation in cardiac output caused by thermal noise is on the order of 1% in clinically used free breathing protocols, and on the order of 3-5% in breath-hold protocols with higher parallel imaging factors. CONCLUSIONS: It is possible to calculate confidence intervals for Cartesian PC contrast flow measurements directly without the need for time-consuming pseudo replica reconstructions.

Identified mortality risk factors associated with presentation, initial hospitalisation, and interstage period for the Norwood operation in a multi-centre registry: a report from the national pediatric cardiology-quality improvement collaborative.

INTRODUCTION: Despite improvements in care following Stage 1 palliation, interstage mortality remains substantial. The National Pediatric Cardiology-Quality Improvement Collaborative captures clinical process and outcome data on infants discharged into the interstage period after Stage 1. We sought to identify risk factors for interstage mortality using these data. MATERIALS AND METHODS: Patients who reached Stage 2 palliation or died in the interstage were included. The analysis was considered exploratory and hypothesis generating. Kaplan-Meier survival analysis was used to screen for univariate predictors, and Cox multiple regression modelling was used to identify potential independent risk factors. RESULTS: Data on 247 patients who met the criteria between June, 2008 and June, 2011 were collected from 33 surgical centres. There were 23 interstage mortalities (9%). The identified independent risk factors of interstage mortality with associated relative risk were: hypoplastic left heart syndrome with aortic stenosis and mitral atresia (relative risk = 13), anti-seizure medications at discharge (relative risk = 12.5), earlier gestational age (relative risk = 11.1), nasogastric or nasojejunal feeding (relative risk = 5.5), unscheduled readmissions (relative risk = 5.3), hypoplastic left heart syndrome with aortic atresia and mitral stenosis (relative risk = 5.2), fewer clinic visits with primary cardiologist identified (relative risk = 3.1), and fewer post-operative vasoactive medications (relative risk = 2.2). CONCLUSION: Interstage mortality remains substantial, and there are multiple potential risk factors. Future efforts should focus on further exploration of each risk factor, with potential integration of the factors into surveillance schemes and clinical practice strategies.

Anomalous left coronary artery from the right coronary cusp with gene positive apical hypertrophic cardiomyopathy: a case report and literature review.

In the United States, hypertrophic cardiomyopathy and coronary artery anomalies account for the leading two causes of sudden death in athletes. We present a case of a patient with an anomalous origin of the left main from the right coronary sinus with associated gene-confirmed hypertrophic cardiomyopathy. The patient underwent surgical repair with unroofing of the intramural portion of the left main coronary artery with a good result. We also review the reported cases in the medical literature describing this uncommon association between anomalous coronary artery origin and hypertrophic cardiomyopathy.

Influence of fetal diagnosis on the clinical presentation of a vascular ring.

A fetus had a diagnosis of a vascular ring formed by a right aortic arch with an aberrant left subclavian artery. The infant experienced isolated dysphagia and vomiting 3 months after birth. Magnetic resonance imaging (MRI) confirmed the vascular ring and demonstrated profound, isolated esophageal dilation with normal airways. The severity of postnatal symptoms due to a vascular ring is difficult to determine in utero. Expectant management of the lesion is necessary, and use of MRI as the imaging method allows for both confirmation of the diagnosis and evaluation of the airway and esophagus while avoiding radiation.