Magnetic resonance imaging (MRI) techniques can provide real-time measurements of volume in a fetal heart, and may better enable physicians to plan care for infants with heart defects, according to a new study. By producing three-dimensional measurements, functional MRIs may represent an advance over the current technology, fetal echocardiography.
"With echocardiography, the heart looks like a shadow. It looks more like a heart with real-time MRI, with excellent soft tissue contrast," said pediatric cardiologist Mark A. Fogel, M.D., director of Cardiac MRI at The Children's Hospital of Philadelphia. A research team led by Dr. Fogel reported preliminary findings based on studies on two fetuses in the September/October 2005 issue of Fetal Diagnosis and Therapy. It was the first example of functional MRI used for cardiac imaging in fetuses.
MRI produces three-dimensional images, whereas echocardiography typically relies on geometric assumptions to measure how big the heart is in the fetus, added Dr. Fogel. One consequence of this capability is that MRI can directly measure the volume of the heart's ventricles.
Echocardiography, which uses reflected ultrasound waves to produce images, may allow physicians to estimate such volumes, but only if the heart has a normal shape. "Many heart diseases involve abnormal shapes, and accurately measuring ventricular volume in such cases is important in assessing how well the heart is working, and in guiding doctors to the most appropriate treatment," said Dr. Fogel.