Cardiac Imaging in Patients After Fontan Palliation: Which Test and When?

The Fontan operation represents the final stage of a series of palliative surgical procedures for children born with complex congenital heart disease, where a "usual" biventricular physiology cannot be restored. The palliation results in the direct connection of the systemic venous returns to the pulmonary arterial circulation without an interposed ventricle. In this unique physiology, systemic venous hypertension and intrathoracic pressures changes due to respiratory mechanics play the main role for propelling blood through the pulmonary vasculature. Although the Fontan operation has dramatically improved survival in patients with a single ventricle congenital heart disease, significant morbidity is still a concern. Patients with Fontan physiology are in fact suffering from a multitude of complications mainly due to the increased systemic venous pressure. Consequently, these patients need close clinical and imaging monitoring, where cardiac exams play a key role. In this article, we review the main cardiac imaging modalities available, summarizing their main strengths and limitations in this peculiar setting. The main purpose is to provide a practical approach for all clinicians involved in the care of these patients, even for those less experienced in cardiac imaging.

Compressed Sensing Cardiac Cine Imaging Compared with Standard Balanced Steady-State Free Precession Cine Imaging in a Pediatric Population.

Purpose: To compare real-time compressed sensing (CS) and standard balanced steady-state free precession (bSSFP) cardiac cine imaging in children. Materials and Methods: Twenty children (mean age, 15 years ± 5 [SD], range, 7-21 years; 10 male participants) with biventricular congenital heart disease (n = 11) or cardiomyopathy (n = 9) were prospectively included. Examinations were performed with 1.5-T imagers by using both bSSFP and CS sequences in all participants. Quantification of ventricular volumes and function was performed for all images by two readers blinded to patient diagnosis and type of sequence. Values were correlated with phase-contrast flow measurements by one reader. Intra- and interreader agreement were analyzed. Results: There were no significant differences between ventricular parameters measured on CS compared with those of bSSFP (P > .05) for reader 1. Only ejection fraction showed a significant difference (P = .02) for reader 2. Intrareader agreement was considerable for both sequences (bSSFP: mean difference range, +1 to -2.6; maximum CI, +7.9, -13; bias range, 0.1%-4.1%; intraclass correlation coefficient [ICC] range, 0.931-0.997. CS: mean difference range, +7.4 to -5.6; maximum CI, +37.2, -48.8; bias range, 0.5%-7.5%; ICC range, 0.717-0.997). Interreader agreement was acceptable but less robust, especially for CS (bSSFP: mean difference range, +2.6 to -5.6; maximum CI, +60.7, -65.3; bias range, 1.6%-6.2%; ICC range, 0.726-0.951. CS: mean difference range, +10.7 to -9.1; maximum CI, +87.5, -84.6; bias range, 1.1%-17.3%; ICC range, 0.509-0.849). The mean acquisition time was shorter for CS (20 seconds; range, 17-25 seconds) compared with that for bSSFP (160 seconds; range, 130-190 seconds) (P < .001). Conclusion: CS cardiac cine imaging provided equivalent ventricular volume and function measurements with shorter acquisition times compared with those of bSSFP and may prove suitable for the pediatric population.Keywords: Compressed Sensing, Balanced Steady-State Free Precession, Cine Imaging, Cardiovascular MRI, Pediatrics, Cardiac, Heart, Cardiomyopathies, Congenital, Segmentation© RSNA, 2022.

Arrhythmogenic cardiomyopathy in children according to "Padua criteria": Single pediatric center experience.

INTRODUCTION: The aim of this study was to report clinical and arrhythmic features in a pediatric population affected by arrhythmogenic cardiomyopathy (ACM). Moreover, we assessed the concordance between the 2010 International Task Force criteria (ITF) and the 2020 Padua criteria. METHODS: Inclusion criteria were "definite" or "borderline" ACM diagnosed according to the "Padua criteria" in patients <18 years old. History, electrocardiograms, ECG-holter monitorings, exercise testings, imaging investigations, electrophysiological studies, genetic testings and follow-up data were collected. RESULTS: We enrolled 21 patients (mean age 13.9 ± 2 years). Most of them presented for minor arrhythmias. Premature ventricular complexes burden was 7.9 ± 10%. Cardiac magnetic resonance (19/21, 90.5% patients) showed right ventricular (RV) dilatation, wall motion abnormalities and late gadolinium enhancement (LGE) of both ventricles as predominant features [in 9 patients (52.9%) LGE left ventricle]. Genetic results (19/21 patient) showed compound heterozygous variants in 3/19 patients (15.8%), digenic in 3/19 (15.8%) and single in 6/19 (31.6%). Cardiac defibrillator (ICD) was indicated in 15 patients (71.4%): 6 in class I, 7 in class IIa, 2 in class IIb. Appropriate shocks occurred in 2 patients (13.3%), follow-up 5.46 ± 3.17 years According to 2010 ITF criteria: among the 18 patients with a "definite" ACM diagnosis, one patient would have had a "borderline" diagnosis, three a "possible" diagnosis and one no diagnosis and among the three patients with "borderline" diagnosis two would have had a "possible" diagnosis. CONCLUSIONS: Pediatric ACM can be diagnosed in the majority of cases secondary to incidental finding of simple ventricular arrhythmias. PVC burden is low and exercise induced arrhythmias rarely occur. Few patients with ICD experience appropriate shocks. "Padua criteria" improve the diagnostic accuracy.

Blood flow characteristics after aortic valve neocuspidization in paediatric patients: a comparison with the Ross procedure.

AIMS: The aortic valve (AV) neocuspidization (Ozaki procedure) is a novel surgical technique for AV disease that preserves the natural motion and cardiodynamics of the aortic root. In this study, we sought to evaluate, by 4D-flow magnetic resonance imaging, the aortic blood flow characteristics after AV neocuspidization in paediatric patients. METHODS AND RESULTS: Aortic root and ascending aorta haemodynamics were evaluated in a population of patients treated with the Ozaki procedure; results were compared with those of a group of patients operated with the Ross technique. Cardiovascular magnetic resonance studies were performed at 1.5 T using a 4D flow-sensitive sequence acquired with retrospective electrocardiogram-gating and respiratory navigator. Post-processing of 4D-flow analysis was performed to calculate flow eccentricity and wall shear stress. Twenty children were included in this study, 10 after Ozaki and 10 after Ross procedure. Median age at surgery was 10.7 years (range 3.9-16.5 years). No significant differences were observed in wall shear stress values measured at the level of the proximal ascending aorta between the two groups. The analysis of flow patterns showed no clear association between eccentric flow and the procedure performed. The Ozaki group showed just a slightly increased transvalvular maximum velocity. CONCLUSION: Proximal aorta flow dynamics of children treated with the Ozaki and the Ross procedure are comparable. Similarly to the Ross, Ozaki technique restores a physiological laminar flow pattern in the short-term follow-up, with the advantage of not inducing a bivalvular disease, although further studies are warranted to evaluate its long-term results.

Dynamic contrast-enhanced magnetic resonance lymphangiography in pediatric patients with central lymphatic system disorders.

Central conducting lymphatics (CCLs) disorders represent a broad spectrum of clinical entities ranging from self-limiting traumatic leaks treated by conservative strategies, to complex lymphatic circulation abnormalities that are progressive and unresponsive to currently available treatments. Dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) performed by intranodal injection of gadolinium-based contrast material is a recently developed technique which allows a minimally invasive evaluation of the CCL abnormalities providing a dynamic assessment of lymph flow and its pathways. In our institution, DCMRL is performed after bilateral cannulation of inguinal lymph nodes, using a MR protocol which includes volumetric 3D T2-SPACE (sampling perfection with application-optimized contrasts using different flip-angle evolution) and free-breathing respiratory navigated sequence and TWIST (time-resolved angiography with Interleaved stochastic trajectories) MR angiography sequence, during intranodal injection of paramagnetic contrast medium. Although DCMRL applications in clinical practice are still improving, a minimally invasive assessment of lymphatic pathways is particularly important both in pediatric patients with primitive lymphatic system disorders and in children with complex congenital heart disease associated with CCL impairment.

Noninvasive imaging of congenital cardiovascular defects.

Advances in the treatment have drastically increased the survival rate of congenital heart disease (CHD) patients. Therefore, the prevalence of these patients is growing. Imaging plays a crucial role in the diagnosis and management of this population as a key component of patient care at all stages, especially in those patients who survived into adulthood. Over the last decades, noninvasive imaging techniques, such as cardiac magnetic resonance (CMR) and cardiac computed tomography (CCT), progressively increased their clinical relevance, reaching stronger levels of accuracy and indications in the clinical surveillance of CHD. The current review highlights the main technical aspects and clinical applications of CMR and CCT in the setting of congenital cardiovascular abnormalities, aiming to address a state-of-the-art guidance to every physician and cardiac imager not routinely involved in the field.

Echocardiographic two-dimensional speckle tracking identifies acute regional myocardial edema and sub-acute fibrosis in pediatric focal myocarditis with normal ejection fraction: comparison with cardiac magnetic resonance.

The aim here was to describe the role of speckle tracking echocardiography (STE), in identifying impairment in systolic function in children and adolescents with focal myocarditis and without reduction in ejection fraction. We describe data from 33 pediatric patients (age 4-17 years) admitted for focal myocarditis, confirmed by cardiac magnetic resonance (CMR), and without impaired ejection fraction and/or wall motion abnormalities. All children underwent Doppler echocardiography examination with analysis of global (G) and segmental longitudinal strain (LS) and CMR for the quantification of edema and myocardial fibrosis. Reduction in LS was defined according to age-specific partition values. At baseline, impaired GLS was present in 58% of patients (n = 19), albeit normal ejection fraction. LS was also regionally impaired, according to the area of higher edema at CMR (i.e. most impaired at the level of the infero-lateral segments as compared to other segments (p < 0.05). GLS impairment was also moderately correlated with the percentage edema at CMR (r = - 0.712; p = 0.01). At follow-up, GLS improved in all patients (p < 0.001), and normal values were found in 13/19 patients with baseline reduction. Accordingly persistent global and regional impairment was still observed in 6 patients. Patients with persistent LS reduction demonstrated residual focal cardiac fibrosis at follow-up CMR. Both global and regional LS is able to identify abnormalities in systolic longitudinal mechanics in children and adolescents with focal myocarditis and normal ejection fraction. The reduction in LS is consistent with edema amount and localization at CMR. Furthermore, LS identifies regional recovery or persistent cardiac function impairment, possibly related to residual focal fibrosis.

Dual-source computed tomography coronary artery imaging in children.

Computed tomography (CT) has a well-established diagnostic role in the assessment of coronary arteries in adults. However, its application in a pediatric setting is still limited and often impaired by several technical issues, such as high heart rates, poor patient cooperation, and radiation dose exposure. Nonetheless, CT is becoming crucial in the noninvasive approach of children affected by coronary abnormalities and congenital heart disease. In some circumstances, CT might be preferred to other noninvasive techniques such as echocardiography and MRI for its lack of acoustic window influence, shorter acquisition time, and high spatial resolution. The introduction of dual-source CT has expanded the role of CT in the evaluation of pediatric cardiovascular anatomy and pathology. Furthermore, technical advances in the optimization of low-dose protocols represent an attractive innovation. Dual-source CT can play a key role in several clinical settings in children, namely in the evaluation of children with suspected congenital coronary artery anomalies, both isolated and in association with congenital heart disease. Moreover, it can be used to assess acquired coronary artery abnormalities, as in children with Kawasaki disease and after surgical manipulation, especially in case of transposition of the great arteries treated with arterial switch operation and in case of coronary re-implantation.

Quantitative vs. qualitative evaluation of static stress computed tomography perfusion to detect haemodynamically significant coronary artery disease.

Aims: To compare the diagnostic accuracy of stress computed tomography myocardial perfusion (CTP) for the detection of significant coronary artery disease with visual approach vs. quantitative analysis with transmural perfusion ratio (TPR) in consecutive symptomatic patients scheduled for invasive coronary angiography (ICA) plus invasive fractional flow reserve (FFR). Methods and results: Eighty-eight consecutive symptomatic patients underwent rest coronary computed tomography angiography (cCTA) followed by static stress-CTP. Diagnostic accuracy of cCTA + stress-CTP with visual evaluation and with TPR measurement was calculated and compared with ICA and invasive FFR. Addition of stress-CTP with qualitative evaluation to rest-cCTA showed sensitivity, specificity, negative and positive predictive values, and accuracy at a vessel and patient level of 92%, 92%, 97%, 82%, 92% and 98%, 80%, 97%, 82%, 89%, respectively indicating a significant improvement of specificity, positive predictive value, and accuracy values vs. rest-cCTA in both models. Similarly, addition of stress-CTP with TPR evaluation to rest-cCTA showed sensitivity, specificity, negative and positive predictive values, and accuracy at a vessel and patient level of 84%, 90%, 93%, 76%, 88% and 91%, 71%, 89%, 75%, 81%, respectively indicating a significant improvement of specificity, positive predictive value values vs. rest-cCTA only in a vessel-based model and of positive predictive value in a patient-based model. When cCTA + stress-CTP with qualitative evaluation was compared with cCTA + stress-CTP with TPR estimation, no differences were found in terms of diagnostic performance. Conclusion: The addition of stress-CTP with visual evaluation to cCTA imaging has similar diagnostic performance when compared with the quantitative analysis of myocardial perfusion based on TPR measurement.

A huge Morgagni hernia with compression of the right ventricle.

A 21 year old male with no relevant medical history presented to our Institution for further assessments of a right paracardiac mass founded on a chest X-ray. Chest computed tomography revealed a wide median defect of the diaphragm at the level of xiphoid process of the sternum, with the herniation of omental fat tissue in the mediastinum. Cardiac magnetic resonance confirmed the presence of a huge hernia originating from the foramen of Morgagni (sterno-costal hiatus), displacing the heart leftwards and posteriorly and compressing the right ventricle (RV), giving to it a tubular shape.The signal characteristics were typical of fat tissue, with hyperintense signal in T1 and T2 weighted black blood images and homogeneus signal suppression on STIR T2 black blood images. Short axis real time cine images, performed during deep inspiration, showed an early diastolic ventricular septal bounce, with flattening of the interventricular septum during mid-late diastole: they represented signs of diastolic dysfunction of the right ventricle, resembling a sort of "pseudo-constrictive" pathophysiological model. The patient was thus referred to surgical repair of the diaphragmatic defect.

Multimodality imaging evaluation of a primary cardiac lymphoma.

Primary cardiac lymphoma is a rare form of non-Hodgkin lymphoma that involves the heart with extension to pericardium and great vessels. Prognosis is poor in the absence of a prompt diagnosis and adequate therapy. Differential diagnosis includes malignant neoplasms such as angiosarcoma or metastatic carcinoma and melanoma. Clinical manifestations may be heterogeneous. Multimodality imaging work-up represents the best method for tumor detection and evaluation of its size and extension: echocardiography, computed tomography, magnetic resonance imaging, and nuclear imaging are the best imaging tools. Definitive diagnosis is achieved with cytological and histological evaluation. We report the case of a 76-year-old woman admitted to our emergency department with symptoms of congestive heart failure. Multimodality imaging work-up showed a mediastinal bulky tumor involving heart and pericardium. Pathology revealed a large B-cell primary cardiac lymphoma.