Publications by authors named "Christopher Z Lam"

Article Synopsis
  • A newborn with a rare heart condition was found to have an unusual liver blood flow pattern during a CT scan that was initially thought to be a blood clot.
  • The case highlights how the baby's unique anatomy affects liver blood flow distribution, leading to the misinterpretation of imaging results.
  • Gaining a clearer understanding of these hepatic perfusion abnormalities can help medical professionals correctly identify similar cases in the future, preventing misdiagnosis and extra tests.
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  • A study was conducted to assess the effectiveness of a specific MRI technique (delayed 3D IR FLASH) in evaluating the lower airways of children during routine cardiovascular magnetic resonance imaging.
  • The study included 180 pediatric patients, with a high image quality rating and visibility of lower airways; around 21% of patients showed lower airway abnormalities, particularly among those with congenital heart disease.
  • The results suggest that this MRI method is highly reliable and effective for viewing lower airway anatomy, enhancing the potential for identifying issues in children with heart conditions.
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  • Patients with congenital heart disease, particularly those who have undergone the Fontan procedure for single ventricle issues, face a high risk of sudden cardiac events (SCE) and early mortality, highlighting the importance of identifying risk factors.
  • In a study involving 3,132 Fontan patients, 3.5% experienced SCE over an average follow-up of 4 years, with 36% of those cases resulting in death.
  • Key risk factors for SCE included higher NYHA functional class, history of protein-losing enteropathy or plastic bronchitis, large end-diastolic volume index, and reduced ejection fraction, all of which can help in predicting and preventing such events.
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Assessment of the right ventricular outflow tract and pulmonary arteries (RVOT) for percutaneous pulmonary valve implantation (PPVI) uses discrete measurements (diameters and lengths) from medical images. This multi-centre study identified the 3D RVOT shape features prevalent in patients late after surgical repair of congenital heart disease (CHD). A 3D RVOT statistical shape model (SSM) was computed from 81 retrospectively selected CHD patients (14.

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  • - The study utilized data from the FORCE registry to analyze cardiac magnetic resonance (CMR) metrics in healthier Fontan patients, aiming to create Fontan-specific z-scores that consider different ventricular morphologies.
  • - The "healthier" cohort consisted of 885 patients, primarily children, who were assessed for ventricular size and function against those with adverse outcomes, revealing that those with left ventricle morphology had better metrics.
  • - Comparisons showed adults had lower blood flow in the ascending aorta than children, and patients with adverse outcomes tended to have higher heart volumes and mass, which suggests a link between ventricular morphology and patient prognosis post-Fontan surgery.
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  • Long-term enlargement of the aortic arch after reconstruction in patients with hypoplastic left heart syndrome (HLHS) was studied using measurements from 50 patients who underwent Fontan completion.* -
  • Over time, the dimensions of the aortic arch increased significantly after reconstruction, with peak enlargement typically occurring around 7 to 12 months post-surgery, followed by a gradual decline in growth into adolescence.* -
  • Both Norwood and hybrid surgical strategies resulted in similar patterns of aortic arch enlargement, suggesting the need to investigate surgical factors that could optimize growth outcomes.*
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  • Fontan patients generally have reduced exercise capacity, but some are categorized as high-performing Fontan (HPF) patients with excellent exercise capacity.
  • The study aimed to develop a tool to predict peak oxygen uptake for Fontan patients, explore clinical factors linked to HPF status, and analyze long-term outcomes for these patients.
  • Findings indicated that HPF patients had better left ventricular morphology, were less likely to have certain complications, and had a significantly lower risk of death or needing a heart transplant compared to those with lower exercise capacity.
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The need for urgent or emergent cardiovascular imaging in children is rare when compared to adults. Patients may present from the neonatal period up to adolescence, and may require imaging for both traumatic and non-traumatic causes. In children, coronary pathology is rarely the cause of an emergency unlike in adults where it is the main cause.

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Purpose Of Review: In the ever-evolving field of medical imaging, this review highlights significant advancements in preoperative and postoperative imaging for Tetralogy of Fallot (TOF) and double outlet right ventricle (DORV) over the past 18 months.

Recent Findings: This review showcases innovations in echocardiography such as 3D speckle tracking echocardiography (3DSTE) for assessing right ventricle-pulmonary artery coupling (RVPAC) and Doppler velocity reconstruction (DoVeR) for intracardiac flow fields evaluation. Furthermore, advances in assessment of cardiovascular anatomy using computed tomography (CT) improve the integration of imaging in ablation procedures.

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Purpose To develop an end-to-end deep learning (DL) pipeline for automated ventricular segmentation of cardiac MRI data from a multicenter registry of patients with Fontan circulation (Fontan Outcomes Registry Using CMR Examinations [FORCE]). Materials and Methods This retrospective study used 250 cardiac MRI examinations (November 2007-December 2022) from 13 institutions for training, validation, and testing. The pipeline contained three DL models: a classifier to identify short-axis cine stacks and two U-Net 3+ models for image cropping and segmentation.

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Article Synopsis
  • The SVR Trial aimed to compare the survival benefits of two surgical options for patients with hypoplastic left heart syndrome: the modified Blalock-Taussig-Thomas shunt (BTTS) and the right ventricle to pulmonary artery conduit (RVPAS).
  • The follow-up study (SVRIII) focused on assessing the impact of shunt type on right ventricle function using cardiac magnetic resonance (CMR) imaging in a cohort of 237 participants aged 10 to 12.5 years, with 75% undergoing CMR exams.
  • Findings revealed that while a high percentage of CMR studies (94%) were diagnostic for right ventricle ejection fraction (RVEF), there were
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Objectives: To assess abnormal liver enhancement on 15-20 min delayed 3D high-resolution late gadolinium enhancement (3D HR LGE) sequence in patients with Fontan circulation.

Methods: Retrospective study of pediatric Fontan patients (< 18 years old) with combined cardiac-liver MRI from January 2018 to August 2021. Abnormal hepatic enhancement was graded (0-3) for each lobe, summed for a total liver enhancement score (0-6), and compared to repaired tetralogy of Fallot (rTOF) patients.

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Aims: To quantify thoracic lymphatic burden in paediatric Fontan patients using MRI and correlate with clinical status.

Methods And Results: Paediatric Fontan patients (<18-years-old) with clinical cardiac MRI that had routine lymphatic 3D T2 fast spin echo (FSE) imaging performed from May 2017 to October 2019 were included. 'Lymphatic burden' was quantified by thresholding-based segmentation of the 3D T2 FSE maximum intensity projection image and indexed to body surface area, performed by two independent readers blinded to patient status.

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Cardiac tumors in children are rare and the majority are benign. The most common cardiac tumor in children is rhabdomyoma, usually associated with tuberous sclerosis complex. Other benign cardiac masses include fibromas, myxomas, hemangiomas, and teratomas.

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The pulmonary circulation after one and one-half ventricle repair is complex because of the direct connection of two sources of blood flow. Associated pulmonary regurgitation further complicates the pulmonary circulation. We report the complex hemodynamics depicted by phase-contrast magnetic resonance imaging in a patient with one and one-half ventricle circuit and severe pulmonary regurgitation.

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Purpose: To assess regional blood flow in fasting pediatric patients with Fontan circulation by using MRI and to explore associations with clinical parameters.

Materials And Methods: In this retrospective study, pediatric patients who had undergone the Fontan procedure (<18 years of age) and had undergone clinical cardiac MRI, performed after at least 4 hours of fasting, between 2018 and 2021 were included. Regional blood flow was compared with published healthy volunteer data ( = 19) and assessed in relation to hemodynamic parameters and clinical status.

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Background: Cardiac rhabdomyoma are the most common cardiac tumour in childhood and are associated with tuberous sclerosis complex (TSC) up to 96% of infant cases. They classically manifest in the foetal and neonatal period, undergo spontaneous regression in the first years of life and are associated with arrhythmia in part due to interruption of normal conduction pathways by the tumour.

Case Summary: We present a case of a 3-year-old boy with a long-standing history of atrial ectopy who was incidentally found to be in atrial flutter due to a new, rapidly growing cardiac rhabdomyoma impacting ventricular function.

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Pediatric hypertrophic cardiomyopathy (HCM) is the most common form of cardiomyopathy in children and a leading cause of sudden cardiac death. Yet, the association between genotype variation, phenotype expression, and adverse events in pediatric HCM has not been fully elucidated. Although the literature on this topic is evolving in adult HCM, the evidence in children is lacking.

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Cardiovascular magnetic resonance (CMR) and cardiac computed tomography (CCT) are robust cross-sectional imaging modalities that are increasingly being used to guide the diagnosis and management of those born with single-ventricle physiology. The purpose of this review is to acquaint the reader with the wide range of cross-sectional imaging applications that can be applied in this population. Illustrative examples of information provided by CMR and CCT are included, such as delineation of cardiac anatomy, measurement of ventricular volumetry, interrogation of vascular anatomy and flows, evaluation of myocardial viability, and exclusion of thromboembolic disease.

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Background: Dynamic contrast-enhanced magnetic resonance imaging (MRI) of the liver in pediatric Fontan patients often shows peripheral reticular areas of hypoenhancement, which has not been studied in detail.

Objective: To semiquantitatively score the hepatic MR perfusion abnormality seen in pediatric Fontan patients, and to correlate the perfusion abnormality with functional clinical and hemodynamic parameters.

Materials And Methods: All children (< 18 years old) after Fontan palliation with combined clinical cardiac and liver MRI performed between May 2017 and April 2019 were considered for inclusion.

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