The History of MCG
The relationship between electric and magnetic fields has been known for centuries, yet it was not until 1963 that the magnetic field of the heart was measured by Baule and McFee.
This was achieved by using two identical coils wrapped millions of times around a ferrite core and placed parallel to each other on the subject’s chest. Although in an attempt to reduce urban magnetic disturbance the experiment was conducted in an open field, the images obtained were of poor quality due to magnetic background noise.
Publication of this work stimulated interest from several other research groups around the world. However, the negative impact of noise on image quality remained a significant hindrance that served only to discourage widespread adoption of the technology.
The turning point came with the development of a sensitive detector known as a superconducting quantum interference device (SQUID). When first used in a magnetically shielded room the device produced a MCG waveform that could be visualised just as clearly as the conventional electrocardiogram (See figure 1). Publication of this result in 1970 heralded the birth of Magnetocardiography.
Interest in magnetic signals grew steadily over the next 5 years until the first international workshop was held at MIT in 1976.
Over the last 4 decades interest in the diagnostic potential of MCG has grown exponentially.
This is largely attributable to the appearance of unshielded SQUID devices in the late 1990s. However, continued reliance on large immovable equipment that is expensive to maintain, has limited the clinical application of MCG to a small but expanding group of research clinicians worldwide. Despite this, a large body of evidence suggests that an unshielded MCG device is a potentially powerful tool for the diagnosis of a multitude of cardiac abnormalities in the human heart.
Vitalscan from Quantum Imaging builds on this evidence and research to perform a simple and passive scan at the patient’s bedside in around 3 minutes; outputs can include a trace, numerical data and a 2D visual magnetic field map of the heart. The device can be used in a routine clinical area and is designed to be used by existing emergency room staff needing little additional training to that needed to perform a routine electrocardiogram (ECG).