Fetal cardiac MRI (fCMR) is an emerging diagnostic tool for evaluating congenital heart disease (CHD), particularly when ultrasound (US) encounters limitations.
The diagnostic pathway for fetal heart diseases begins with a screening morphological US.
A comprehensive anatomical evaluation is essential for a complete prenatal diagnosis of CHD, as it plays a crucial role in parental counseling, postnatal treatment planning, and outcome assessment. When CHD is suspected during routine midtrimester US screening, a detailed fetal echocardiogram represents the primary diagnostic tool for accurately identifying CHD. However, echocardiography may be limited by maternal or fetal factors, as well as poor acoustic windows in advanced gestation due to fetal position or rib calcification.1
As a result, fCMR has emerged as a complementary imaging technique to evaluate cardiac volumes and function, to quantify aortic and pulmonary flow, potential shunt and regurgitation fraction. Furthermore, it is able to improve evaluation of patients with suspected aortic arch anomalies and other CHD.2
Additionally, it is useful for detecting extracardiac anomalies frequently associated with CHD and for characterizing cardiac masses.3,4 Moreover, it is also helpful for detecting noncardiac abnormalities such as diaphragmatic hernia or congenital brain defects. Nevertheless, diagnosing CHD with fetal MRI presents challenges due to the small size of fetal cardiovascular structures, the rapid cardiac cycle, and various motion artifacts.1
In fetal echocardiography, ventricular dimensions are estimated using the four-chamber view5 and fetal cardiac output can be estimated by echocardiogram in a single plane, with the measurement of semilunar valve dimension, pulse wave Doppler across the semilunar valve and fetal heart rate.6
Accurate quantification of fetal cardiac volumes is essential for diagnosing CHD, and fCMR, represents a promising non-invasive modality for assessing fetal cardiac function.
A key component of ventricular function assessment using fCMR is the quantification of ventricular volumetry with a reproducible method. These quantitative measurements provide essential insights into fetal cardiovascular physiology, enhancing the accuracy of CHD diagnosis.
According to the literature, there is still no established standard for assessing ventricular volumes and function using fCMR, as normal reference values for cardiac volumetry in fetuses have yet to be defined.
This study aims to evaluate and compare the left and right ventricle (LV and RV) volumes and function, focusing on variability between measurements obtained from four-chamber and short-axis views.