Fetal Cardiac Imaging for Congenital Heart Disease—Is Cardiac Magnetic Resonance Imaging the Future?

Abstract

Salehi et al 1 present a single-center cohort study to determine the diagnostic utility of fetal cardiac magnetic resonance (CMR) imaging for improving the prenatal diagnosis of congenital heart defects (CHDs) when fetal echocardiogram fails to visualize the cardiac anatomy. The study included 31 fetuses with suspected CHD in whom fetal CMR was performed between gestational ages of 31 and 39 weeks due to inadequacy of fetal echocardiogram imaging. Fetal CMR affected clinical management in 26 cases (84%). Salehi et al 1 concluded that fetal CMR improved prenatal diagnosis of CHD and thus affected clinical decision-making and counseling when fetal echocardiogram imaging was technically limited. The field of fetal cardiology emerged in 1980 when 3 pioneers in cardiac imaging-Kleinman, Allen, and Sahn-first described 2-dimensional fetal echocardiography imaging in fetuses between 14 and 41 weeks gestational age. 2-4 They demonstrated fetal cardiac anatomy in more than 350 fetuses, and Kleinman et al 2 even identified univentricular CHD and fetal cardiac dysrhythmia. During the past 40 years, fetal echocardiography has made significant technological advances, including improved color Doppler assessment, 3-dimensional imaging, and 4-dimensional imaging. These innovations have led to high diagnostic accuracy of fetal echocardiogram imaging, allowing for identification of complex and critical CHDs as early as 12 weeks gestation as well as appropriate delivery planning and counseling. Nevertheless, fetal echocardiography can be technically limited by factors such as maternal body habitus, oligohydramnios, uterine masses, gestational age, multiple gestation, and fetal position, which result in incomplete imaging of the fetal cardiac structures. In these cases, fetal CMR may prove to be an important adjunct to a fetal echocardiogram because it is not limited by these factors. Fetal CMR can image the fetal heart from any plane, allowing for a large field of view. There are no reported risks of fetal CMR to the pregnant mother or fetus; however, fetal CMR is significantly more expensive, requires more resources, and is time-consuming compared with fetal echocardiography. The visualization of the fetal heart by fetal CMR is challenging due to the small heart size, fast fetal heart rate, and fetal motion. Technical advances and improvements in gating and reconstruction methods have been previously described by Roy et al. 5 Recognizing these strengths and limitations of both fetal echocardiography and fetal CMR, the current study by Salehi et al 1 focuses on those fetuses with unresolved, clinically important questions regarding the CHD diagnosis after fetal echocardiogram review by experienced fetal cardiologists and radiologists. They further delineate a fetal CMR method for improved visualization of specific cardiac structures and function, namely the aortic arch, pulmonary artery, arterial duct, and ventricles. 1 With this well-defined cohort and analysis, Salehi et al 1 optimized the utility of fetal CMR in certain CHDs for...

Feasibility of Non-Gated Dynamic Fetal Cardiac MRI for Identification of Fetal Cardiovascular Anatomy

“…In contrast, another study assessed 20 fetuses at a mean gestational age of 24 weeks [4]. The diagnostic quality of fetal echocardiography is limited by several factors including maternal body habitus, oligohydramnios, uterine masses, gestational age and fetal position, which may result in incomplete visualization of the fetal cardiac structures [24]. Maternal obesity is considered one of the major limiting factors of obstetric sonography and may reduce visualization rate of the cardiovascular structures by 50% [25].…”

“…Wielandner et al [ 9 ] recommended fetal cardiac MRI after gestational week 25 in order to achieve diagnostic image quality. The examinations of younger fetuses often suffer from insufficient temporal and spatial resolution [ 24 ]. In addition, it has been reported that fetal movements are an important limitation for assessing cardiac anatomy [ 8 ], and in advanced pregnancy, fetal movement may decrease and fewer motion artifacts are expected.…”

The arterial duct and the right aortic arch: telescope into the prenatal defective heart

“…Fetal cardiac imaging emerged in 1980 when Kleinman, Allen and Sahn [2] published their series of two-dimensional echocardiography in the assessment of fetal hearts. The past 40 years has brought significant technological advances in imaging of the fetal cardiovascular system-color Doppler, 3D-and later 4D-echocardiography [2].…”