Friday, May 16, 2025
5/16/2025
Safe and Effective MRI for Pediatric Patients with a Cardiac Implantable Electronic Device - Abstract: A substantial number of infants and children with congenital heart defects (CHD), inherited arrhythmia syndromes, and/or congenital disorders of cardiac conduction require a cardiac implantable electronic device (CIED). The current approach to affixing a CIED lead to the heart of a young patient is to open the chest and sew the lead directly to the epicardium (“epicardial leads”), whereas the approach in older adolescents and adults is passing it through veins and affixing to the endocardium (“endocardial leads”). Once epicardial leads are implanted, however, the patient is no longer eligible for routine magnetic resonance imaging (MRI) due to the increased risk of radiofrequency (RF)-induced heating of myocardial tissue. The problem is exacerbated by the fact that there is no straightforward method to extract leads, so children who receive such leads are excluded from the benefits of MRI even if a subsequent FDA-approved endocardial CIED system replaces an epicardial system when they are older. Such patients are often referred for alternative imaging modalities with ionizing radiation, which may result in suboptimal care and a significant radiation risk for children. Our strong, preliminary data show that CHD patients with a CIED have four-fold higher cumulative effective doses of radiation from computed tomography and X-ray than matched pediatric CHD patients with no CIED, thereby highlighting an urgent need to increase access to MRI for pediatric CIED patients. The 2017 HRS consensus statement is blunt in emphasizing the need for more research: “Given the paucity of data related to the safety of MRI [with epicardial leads], recommendations cannot be made [and] many questions remain unanswered.” Even if MRI safety issues are resolved through engineering, the diagnostic yield of cardiac MRI remains low due to severe image artifact caused by the Implantable Pulse Generator (IPG). Existing “wideband” pulse sequences developed for adults are unsuitable for pediatric CIED patients due to two main reasons: (a) the proximity of IPG to the heart is closer in pediatric patients than adults, necessitating a wider bandwidth RF pulse design; (b) pediatric patients have smaller hearts and faster heart rates than adults, necessitating higher data acquisition acceleration. In direct response to this unmet clinical need, this study seeks to develop innovative technologies to achieve the following three objectives: (1) determine imaging conditions under which MRI can be performed safely in children, regardless of CIED types and abandoned leads; (2) develop, implement, and validate physics-based epicardial lead implantation strategies that minimize the variation and magnitude of RF heating in pediatric patients with a CIED; (3) develop and validate age-specific, free-breathing, wideband cardiovascular MRI pulse sequences that produce diagnostically acceptable image quality in pediatric CIED patients. If successful, our work will extend MRI access to a growing number of pediatric patients with a CIED and deliver age-specific free-breathing wideband pulse sequences that produce diagnostically acceptable image quality.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).