Anthony M. Hlavacek

Characterization of cardiac tumors in children by cardiovascular magnetic resonance imaging: a multicenter experience.

OBJECTIVES The aim of this study was to report the results of an international multicenter experience of cardiac magnetic resonance imaging (MRI) evaluation of cardiac tumors in children, each with histology correlation or a diagnosis of tuberous sclerosis, and to determine which characteristics are predictive of tumor type. BACKGROUND Individual centers have relatively little experience with diagnostic imaging of cardiac tumors in children, because of their low prevalence. The accuracy of cardiac MRI diagnosis on the basis of a pre-defined set of criteria has not been tested. METHODS An international group of pediatric cardiac imaging centers was solicited for case contribution. Inclusion criteria comprised: 1) age at diagnosis ≤18 years; 2) cardiac MRI evaluation of cardiac tumor; and 3) histologic diagnosis or diagnosis of tuberous sclerosis. Data from the cardiac MRI images were analyzed for mass characteristics. On the basis of pre-defined cardiac MRI criteria derived from published data, 3 blinded investigators determined tumor type, and their consensus diagnoses were compared with histologic diagnoses. RESULTS Cases (n = 78) submitted from 15 centers in 4 countries had the following diagnoses: fibroma (n = 30), rhabdomyoma (n = 14), malignant tumor (n = 12), hemangioma (n = 9), thrombus (n = 4), myxoma (n = 3), teratoma (n = 2), and paraganglioma, pericardial cyst, Purkinje cell tumor, and papillary fibroelastoma (n = 1, each). Reviewers who were blinded to the histologic diagnoses correctly diagnosed 97% of the cases but included a differential diagnosis in 42%. Better image quality grade and more complete examination were associated with higher diagnostic accuracy. CONCLUSIONS Cardiac MRI can predict the likely tumor type in the majority of children with a cardiac mass. A comprehensive imaging protocol is essential for accurate diagnosis. However, histologic diagnosis remains the gold standard, and in some cases malignancy cannot be definitively excluded on the basis of cardiac MRI images alone.

Real-Time Three-Dimensional Echocardiography Is Useful in the Evaluation of Patients with Atrioventricular Septal Defects

Objective: We sought to determine whether three‐dimensional echocardiography (3DE) is useful in the evaluation of patients with atrioventricular septal defect (AVSD). Background: Recent advances in 3DE have enhanced its practicality. We assessed whether 3DE provided new information compared to 2DE among patients with AVSD. Methods: We retrospectively reviewed 52 3DE datasets from 51 patients (median age: 4.6 years, range 0–30 years; median BSA: 0.6 m2, range 0.2–1.9 m2) with any type of AVSD during a 1‐year period. 3DE findings were compared to 2DE and surgical reports. For each study, AVSD was classified by 2DE as one of the following: unrepaired balanced defect, repaired balanced defect with residual lesions, repaired balanced defect without residual lesions, or unbalanced defect. 3DE was graded as (1) Additive: 3DE resulted in a new finding or changed diagnosis; (2) Useful: While useful, 3DE did not result in new findings or changed diagnosis; or (3) Not useful. Results: 3DE on unrepaired balanced AVSD and repaired AVSD with residual lesions was more often additive/useful (33/36; 92%) than on repaired AVSD without residual lesions or unbalanced AVSD (9/16 (56%), P=0.009). 3DE was additive or useful in all three patients with unbalanced AVSD being considered for biventricular repair. Useful information obtained by 3DE included: precise characterization of mitral regurgitation and cleft leaflet, substrate for subaortic stenosis, valve anatomy, and presence and location of additional septal defects. Conclusion: 3DE provides useful and additive information in unrepaired balanced AVSD, repaired AVSD with residual lesions, and unbalanced AVSD under consideration for biventricular repair.

Transthoracic real-time three-dimensional echocardiography in the diagnosis and description of noncompaction of ventricular myocardium.

Background: Numerous modalities have been used to diagnose and characterize noncompaction of ventricular myocardium (NCVM) including magnetic resonance imaging, two‐dimensional echocardiography (2DE), contrast‐enhanced 2DE, and angiography. The current case series examines the use of real‐time three‐dimensional transthoracic echocardiography (RT‐3DE) in four such cases of NCVM. Methods: From December 2003 to March 2004, we performed RT‐3DE using a Philips Sonos 7500 echocardiographic scanner equipped with a 2–4 MHz 3D matrix array transthoracic probe, to evaluate four patients with NCVM. The real‐time 3D transthoracic probe allows for dataset acquisition in an ultrasound wedge, which can be manipulated instantaneously. In addition, complete 3D volume rendering is acquired, allowing for volumetric imaging. Results: The age range of the patients was 2 months to 42 years. One patient had the codiagnoses of coarctation of the aorta and bicuspid aortic valve. In all four patients, RT‐3DE enabled diagnosis and provided detailed characterization of the affected myocardium. Entire trabecular projections and intertrabecular recesses were easily visualized simultaneously, and endocardial borders were clearly demarcated. Wall motion abnormalities of the affected myocardium were clearly visualized. The compacted and noncompacted portions of the myocardium could be differentiated well. Conclusions: Our study provides preliminary data highlighting the utility and feasibility of RT‐3DE in the clinical characterization of NCVM. The complex 3D nature of this disorder and the endocardial hypertrabeculation were more readily visualized than with 2DE.

Feasibility and utility of three-dimensional color flow echocardiography of the aortic arch: The "echocardiographic angiogram".

Two‐dimensional transthoracic echocardiography (2DE) is the most commonly used diagnostic modality to evaluate congenital and acquired abnormalities of the aortic arch. However, 2DE is frequently limited in this ability due to the three‐dimensional character of the arch and its interrelationships with other vascular structures. Recently, three‐dimensional echocardiography (3DE) with 3D color flow Doppler became commercially available. We examined the feasibility and utility of 3DE with 3D color Doppler in the evaluation of patients with congenital (native and postoperative) abnormalities of the aortic arch. We found that 3DE color flow provides important diagnostic information in patients with aortic arch anomalies, in a manner that is quick and user‐friendly. In addition, 17 of the 26 patients had their 3DE findings confirmed by additional modalities, providing reasonably significant validation for our findings with 3DE.

Uncertainty quantification in virtual surgery hemodynamics predictions for single ventricle palliation.

The adoption of simulation tools to predict surgical outcomes is increasingly leading to questions about the variability of these predictions in the presence of uncertainty associated with the input clinical data. In the present study, we propose a methodology for full propagation of uncertainty from clinical data to model results that, unlike deterministic simulation, enables estimation of the confidence associated with model predictions. We illustrate this problem in a virtual stage II single ventricle palliation surgery example. First, probability density functions (PDFs) of right pulmonary artery (PA) flow split ratio and average pulmonary pressure are determined from clinical measurements, complemented by literature data. Starting from a zero-dimensional semi-empirical approximation, Bayesian parameter estimation is used to find the distributions of boundary conditions that produce the expected PA flow split and average pressure PDFs as pre-operative model results. To reduce computational cost, this inverse problem is solved using a Kriging approximant. Second, uncertainties in the boundary conditions are propagated to simulation predictions. Sparse grid stochastic collocation is employed to statistically characterize model predictions of post-operative hemodynamics in models with and without PA stenosis. The results quantify the statistical variability in virtual surgery predictions, allowing for placement of confidence intervals on simulation outputs.

Developmental Aortic Arch Anomalies in Infants and Children Assessed With CT Angiography

OBJECTIVE The purpose of this article is to review the normal anatomy of the aortic arch and the most common variations of congenital aortic arch anomalies using low-radiation-dose, defined as a dose-length product of 7-15 mGy × cm, MDCT angiography. CONCLUSION Radiologists should be prepared to fully describe congenital aortic arch anomalies; recognize them on CT angiography, especially the presence or absence of vascular rings or aberrant arteries; and explain their association with the trachea and esophagus.

Hemodynamic effects of left pulmonary artery stenosis after superior cavopulmonary connection: a patient-specific multiscale modeling study.

OBJECTIVE Currently, no quantitative guidelines have been established for treatment of left pulmonary artery (LPA) stenosis. This study aims to quantify the effects of LPA stenosis on postoperative hemodynamics for single-ventricle patients undergoing stage II superior cavopulmonary connection (SCPC) surgery, using a multiscale computational approach. METHODS Image data from 6 patients were segmented to produce 3-dimensional models of the pulmonary arteries before stage II surgery. Pressure and flow measurements were used to tune a 0-dimensional model of the entire circulation. Postoperative geometries were generated through stage II virtual surgery; varying degrees of LPA stenosis were applied using mesh morphing and hemodynamics assessed through coupled 0-3-dimensional simulations. To relate metrics of stenosis to clinical classifications, pediatric cardiologists and surgeons ranked the degrees of stenosis in the models. The effects of LPA stenosis were assessed based on left-to-right pulmonary artery flow split ratios, mean pressure drop across the stenosis, cardiac pressure-volume loops, and other clinically relevant parameters. RESULTS Stenosis of >65% of the vessel diameter was required to produce a right pulmonary artery:LPA flow split <30%, and/or a mean pressure drop of >3.0 mm Hg, defined as clinically significant changes. CONCLUSIONS The effects of <65% stenosis on SCPC hemodynamics and physiology were minor and may not justify the increased complexity of adding LPA arterioplasty to the SCPC operation. However, in the longer term, pulmonary augmentation may affect outcomes of the Fontan completion surgery, as pulmonary artery distortion is a risk factor that may influence stage III physiology.

Veno-venous bridges: the forerunners of the sinus venosus defect.

BACKGROUND Differentiation of the so-called sinus venosus defect from other defects permitting shunting between the atrial chambers remains problematic. The lesion is not a true septal defect, and current theories to explain the existence of the sinus venosus defect fall short. The presence of persistent systemic to pulmonary venous connections has been proposed to explain the existence of the sinus venosus defect. METHODS Clinical histories and radiological findings of six patients are reviewed. Three patients have veno-venous bridges, two have partial anomalous pulmonary venous connections, and one patient has a sinus venosus defect. The clinical information is reviewed, along with current developmental and morphological considerations. DISCUSSION We provide radiographic, developmental, and morphological evidence to support the theory that a so-called sinus venosus defect is the consequence of persistence of foetal systemic to pulmonary veno-venous bridges, rather than of deficiencies in atrial septation.

Variability and Resource Utilization of Bedside Three-dimensional Echocardiographic Quantitative Measurements of Left Ventricular Volume in Congenital Heart Disease

OBJECTIVES This study evaluated the variability and time resource utilization of bedside 3-dimensional echocardiographic left ventricular volume analysis (3D-LVVA) in congenital heart disease (CHD). Background. There are currently limited data on the resource utilization and variability of 3D-LVVA in the CHD. METHODS Four reviewers of varying experience levels were timed performing 15 on-scanner 3D-LVVAs. Inter- and intraobserver variability for left ventricular end-diastolic volume (LVEDV), end-systolic volume (LVESV), and ejection fraction (LVEF) was evaluated. RESULTS Median age was 12.7 years (0.6-33 years). Diagnoses were: normal (n = 4), cardiomyopathy (n = 4), ventricular septal defect (n = 2), and atrioventricular canal, tricuspid atresia, bicuspid aortic valve, left ventricular hypertrophy, and heart transplant (n = 1 each). For interobserver variability, intraclass correlation coefficients (ICCs) for all possible combinations of reviewers were: LVEDV, 0.991-0.999 (P < .01); LVESV, 0.98-0.99 (P < .01); LVEF, 0.95-0.98 (P < .01). Bland-Altman plot mean differences (+/-2SD) were: LVEDV, -3 +/- 14%; LVESV, -5.4 +/- 21.4%; LVEF, 1.2 +/- 14.7%. Interobserver variability of LVESV was not dependent on ventricular volumes (P = .25; r(2) = 0.01) or heart rate (P = .43; r(2) = 0.003). For intraobserver variability, ICCs for 2 reviewers were LVEDV, 0.99, 0.99 (P < .01); LVESV, 0.99, 0.99 (P < .01); and LVEF, 0.94, 0.94 (P < .01), respectively. Bland-Altman plot mean differences (+/-2SD) were: LVEDV, -1 +/- 9.2%; LVESV, 0 +/- 19.6%; LVEF, -2.2 +/- 24%. CONCLUSION Reviewers with varying experience levels can accomplish 3D-LVVA at the bedside with acceptable inter- and intraobserver reproducibility, providing the rationale for integrating 3D-LVVA into the care of CHD patients.

Anomalous origin and course of the coronary arteries.

In the normal heart, the right and left coronary arteries arise from the aortic valvar sinuses adjacent to the pulmonary trunk. The right coronary artery then directly enters the right atrioventricular groove, whereas the main stem of the left coronary artery runs a short course before dividing to become the anterior interventricular and circumflex arteries. These arteries can have an anomalous origin from either the aorta or pulmonary trunk; their branches can have various anomalous origins relative to arterial pedicles. Other abnormal situations include myocardial bridging, abnormal communications, solitary coronary arteries, and duplicated arteries. Understanding of these variations is key to determining those anomalous patterns associated with sudden cardiac death. In the most common variant of an anomalous origin from the pulmonary trunk, the main stem of the left coronary artery arises from the sinus of the pulmonary trunk adjacent to the anticipated left coronary arterial aortic sinus. The artery can, however, arise from a pulmonary artery, or the right coronary artery can have an anomalous pulmonary origin. The key feature in the anomalous aortic origin is the potential for squeezing of the artery, produced by either the so-called intramural origin from the aorta, or the passage of the abnormal artery between the aortic root and the subpulmonary infundibulum.