Atypical atrial septal defects in children: noninvasive evaluation by cardiac MRI

Iatrogenic closure of coronary sinus: an unforseen complication of surgical atrial septal defect closure

Cardiac complication following the surgical closure of a secundum atrial septal defect (ASD) is extremely uncommon in the current era. We report a case of 39-year-old male presented with hemoptysis following an ASD closure 21 years prior and diagnosed to have iatrogenic closure of the coronary sinus at the time of surgical ASD closure. To our best knowledge, this is the first case of such complication reported in the literature.

Biatrial Drainage of the Right Superior Vena Cava: Imaging Findings

Biatrial drainage of the right superior vena cava (SVC) is a rare form of interatrial shunting that can have substantial clinical consequences. Cross-sectional imaging techniques (CT and MRI) are well suited for evaluation and surgical planning. This review article focuses on the embryologic development, hemodynamics, and imaging features to enable a timely diagnosis. Biatrial drainage of the right SVC has important clinical implications, and knowledge of its imaging appearance and hemodynamics is essential in diagnosis and treatment planning. © RSNA, 2020.

Evaluation of atrial septal defects with 4D flow MRI-multilevel and inter-reader reproducibility for quantification of shunt severity

Purpose

With the hypothesis that 4D flow can be used in evaluation of cardiac shunts, we seek to evaluate the multilevel and interreader reproducibility of measurements of the blood flow, shunt fraction and shunt volume in patients with atrial septum defect (ASD) in practice at multiple clinical sites.

Materials and methods

Four-dimensional flow MRI examinations were performed at four institutions across Europe and the US. Twenty-nine patients (mean age, 43 years; 11 male) were included in the study. Flow measurements were performed at three levels (valve, main artery and periphery) in both the pulmonary and systemic circulation by two independent readers and compared against stroke volumes from 4D flow anatomic data. Further, the shunt ratio (Q_p/Q_s) was calculated. Additionally, shunt volume was quantified at the atrial level by tracking the atrial septum.

Results

Measurements of the pulmonary blood flow at multiple levels correlate well whether measuring at the valve, main pulmonary artery or branch pulmonary arteries (r = 0.885–0.886). Measurements of the systemic blood flow show excellent correlation, whether measuring at the valve, ascending aorta or sum of flow from the superior vena cava (SVC) and descending aorta (r = 0.974–0.991). Intraclass agreement between the two observers for the flow measurements varies between 0.96 and 0.99. Compared with stroke volume, pulmonic flow is underestimated with 0.26 l/min at the main pulmonary artery level, and systemic flow is overestimated with 0.16 l/min at the ascending aorta level. Direct measurements of ASD flow are feasible in 20 of 29 (69%) patients.

Conclusion

Blood flow and shunt quantification measured at multiple levels and performed by different readers are reproducible and consistent with 4D flow MRI.

Electronic supplementary material

The online version of this article (10.1007/s10334-018-0702-z) contains supplementary material, which is available to authorized users.

Computational medical imaging and hemodynamics framework for functional analysis and assessment of cardiovascular structures

Cardiac dysfunction constitutes common cardiovascular health issues in the society, and has been an investigation topic of strong focus by researchers in the medical imaging community. Diagnostic modalities based on echocardiography, magnetic resonance imaging, chest radiography and computed tomography are common techniques that provide cardiovascular structural information to diagnose heart defects. However, functional information of cardiovascular flow, which can in fact be used to support the diagnosis of many cardiovascular diseases with a myriad of hemodynamics performance indicators, remains unexplored to its full potential. Some of these indicators constitute important cardiac functional parameters affecting the cardiovascular abnormalities. With the advancement of computer technology that facilitates high speed computational fluid dynamics, the realization of a support diagnostic platform of hemodynamics quantification and analysis can be achieved. This article reviews the state-of-the-art medical imaging and high fidelity multi-physics computational analyses that together enable reconstruction of cardiovascular structures and hemodynamic flow patterns within them, such as of the left ventricle (LV) and carotid bifurcations. The combined medical imaging and hemodynamic analysis enables us to study the mechanisms of cardiovascular disease-causing dysfunctions, such as how (1) cardiomyopathy causes left ventricular remodeling and loss of contractility leading to heart failure, and (2) modeling of LV construction and simulation of intra-LV hemodynamics can enable us to determine the optimum procedure of surgical ventriculation to restore its contractility and health This combined medical imaging and hemodynamics framework can potentially extend medical knowledge of cardiovascular defects and associated hemodynamic behavior and their surgical restoration, by means of an integrated medical image diagnostics and hemodynamic performance analysis framework.

Septum primum malposition defect and inferior sinus venosus defect: a rare association

We present a case of a 2-year-old girl who presented with respiratory distress and umbilical abscess, and was found to have an inferior sinus venosus defect, malposition of the atrial septum primum, absent septum secundum, and anomalous drainage of the right upper and lower pulmonary veins to the right atrium.

Atrial shunts: presentation, investigation, and management, including recent advances in magnetic resonance imaging

Atrial shunts are a common finding in both paediatric and adult populations. Recent developments in advanced imaging have widened the options for diagnosis and evaluation of such shunts. This paper reviews the various types of interatrial communications, discusses the features of clinical presentation in adults and children, and provides an overview of the clinical assessment including physical examination, electrocardiography, echocardiography, cardiac catheterisation, computed tomography, and magnetic resonance imaging. Focus will be placed on recent developments in magnetic resonance imaging that may improve the non-invasive evaluation of atrial shunts.

Magnetic resonance imaging of pediatric lung parenchyma, airways, vasculature, ventilation, and perfusion: state of the art

Magnetic resonance (MR) imaging is a noninvasive imaging modality, particularly attractive for pediatric patients given its lack of ionizing radiation. Despite many advantages, the physical properties of the lung (inherent low signal-to-noise ratio, magnetic susceptibility differences at lung-air interfaces, and respiratory and cardiac motion) have posed technical challenges that have limited the use of MR imaging in the evaluation of thoracic disease in the past. However, recent advances in MR imaging techniques have overcome many of these challenges. This article discusses these advances in MR imaging techniques and their potential role in the evaluation of thoracic disorders in pediatric patients.

Efficacy and safety of deep sedation by non-anesthesiologists for cardiac MRI in children

BACKGROUND

Cardiac MRI has become widespread to characterize cardiac lesions in children. No study has examined the role of deep sedation performed by non-anesthesiologists for this investigation.

OBJECTIVE

We hypothesized that deep sedation provided by non-anesthesiologists can be provided with a similar safety and efficacy profile to general anesthesia provided by anesthesiologists.

MATERIALS AND METHODS

This is a retrospective chart review of children who underwent cardiac MRI over a 5-year period. The following data were collected from the medical records: demographic data, cardiac lesion, American Society of Anesthesiologists (ASA) physical status, sedation type, provider, medications, sedation duration and adverse events or interventions. Image and sedation adequacy were recorded.

RESULTS

Of 1,465 studies identified, 1,197 met inclusion criteria; 43 studies (3.6%) used general anesthesia, 506 (42.3%) had deep sedation and eight (0.7%) required anxiolysis only. The remaining 640 studies (53.5%) were performed without sedation. There were two complications in the general anesthesia group (4.7%) versus 17 in the deep sedation group (3.4%). Sedation was considered inadequate in 22 of the 506 deep sedation patients (4.3%). Adequate images were obtained in 95.3% of general anesthesia patients versus 86.6% of deep sedation patients.

CONCLUSION

There was no difference in the incidence of adverse events or cardiac MRI image adequacy for children receiving general anesthesia by anesthesiologists versus deep sedation by non-anesthesiologists. In summary, this study demonstrates that an appropriately trained sedation provider can provide deep sedation for cardiac MRI without the need for general anesthesia in selected cases.

Medical image diagnostics based on computer-aided flow analysis using magnetic resonance images

Most of the cardiac abnormalities have an implication on hemodynamics and affect cardiovascular health. Diagnostic imaging modalities such as computed tomography and magnetic resonance imaging provide excellent anatomical information on myocardial structures, but fail to show the cardiac flow and detect heart defects in vivo condition. The computerized technique for fluid motion estimation by pixel intensity tracking based on magnetic resonance signals represents a promising technique for functional assessment of cardiovascular disease, as it can provide functional information of the heart in addition to analysis of its anatomy. Cardiovascular flow characteristics can be measured in both normal controls and patients with cardiac abnormalities such as atrial septal defect, thus, enabling identification of the underlying causes of these flow phenomena. This review paper focuses on an overview of a flow analysis scheme based on computer-aided evaluation of magnetic resonance intensity images, in comparison with other commonly used medical imaging modalities. Details of the proposed technique are provided with validations being conducted at selected abnormal cardiovascular patients. It is expected that this new technique can potentially extend applications for characterizing cardiovascular defects and their hemodynamic behavior.

Cardiac MRI: Part 1, cardiovascular shunts

OBJECTIVE

MRI plays an important role in the morphologic and functional evaluation of cardiovascular shunts. Good spatiotemporal resolution, inherent contrast resolution, wide FOV, and multiplanar imaging capabilities make MRI an ideal tool in the investigation of cardiovascular shunts. The velocity-encoded phase-contrast sequence is used in the quantification of a shunt and the steady-state free precession (SSFP) sequence is used in the assessment of the functional impact of a shunt. In this article, the role of MRI in the evaluation of cardiovascular shunts and their respective MRI appearances are described and illustrated.

CONCLUSION

MRI can identify and characterize septal defects, quantify shunts and their impact on cardiac function, and help in the selection of appropriate candidates for percutaneous device placement.

Flow-sensitive four-dimensional magnetic resonance imaging facilitates and improves the accurate diagnosis of partial anomalous pulmonary venous drainage

OBJECTIVES

To assess if flow-sensitive four-dimensional velocity-encoded cine magnetic resonance imaging adds value in diagnosing patients with suspected partial anomalous pulmonary venous drainage.

METHODS

In six patients with echocardiographically suspected partial anomalous pulmonary venous drainage, anatomy was evaluated using standard magnetic resonance imaging including angiography. Functional analysis included shunt calculations from flow measurements. We used four-dimensional velocity-encoded cine magnetic resonance imaging for visualisation of maldraining pulmonary veins and quantification of flow via the maldraining veins and interatrial communications, if present.

RESULTS

In all patients, the diagnosis of partial anomalous pulmonary venous drainage was confirmed by standard magnetic resonance imaging. Shunt volumes ranged from 1.4:1 to 4.7:1. Drainage sites were the superior caval vein (n = 5) or the vertical vein (n = 1). Multiple maldraining pulmonary veins were found in three patients. Pulmonary arteries and veins could be clearly distinguished by selective visualisation using four-dimensional velocity-encoded cine magnetic resonance imaging. Flow measured individually in maldraining pulmonary veins in six patients and across the interatrial communication in three patients revealed a percentage of the overall shunt volume of 30-100% and 58-70%, respectively.

CONCLUSION

Selective visualisation of individual vessels and their flow characteristics by four-dimensional velocity-encoded cine magnetic resonance imaging facilitates in distinguishing adjacent pulmonary arteries and veins and thus improves the accurate diagnosis of maldraining pulmonary veins. By detailed quantification of shunt volumes, additional information for planning of treatment strategies is provided. This method adds clinical value and might replace contrast-enhanced magnetic resonance angiography in these patients in the future.

4D phase-contrast flow cardiovascular magnetic resonance: comprehensive quantification and visualization of flow dynamics in atrial septal defect and partial anomalous pulmonary venous return

The case of an 8-year-old girl with atrial septal defect and associated anomalous pulmonary venous return is presented to illustrate the advantages of four dimensional flow (4D flow) over the current two dimensional flow (2D flow) in terms of time efficiency, easy planning, accurate and individual quantification of the blood sources contributing to the left-to-right shunting from one single acquisition, internal validation of flow measurement accuracy, possibility of reanalysis without rescanning in case of unexpected findings during the postprocessing, and comprehensive understanding of flow insight by use of particle tracing visualization.