Today, the U.S. Food and Drug Administration cleared the first seven tesla (7T) magnetic resonance imaging (MRI) device, more than doubling the static magnetic field strength available for use in the United States. The Magnetom Terra is the first 7T MRI system cleared for clinical use in the United States.
“The overall image quality of MRI improves with higher magnetic field strength,” stated Robert Ochs, Ph.D., director of the Division of Radiological Health in the FDA’s Center for Devices and Radiological Health. “The added field strength allows for better visualization of smaller structures and subtle pathologies that may improve disease diagnosis.”
MRI is a medical imaging procedure that creates images of the internal structures of the body. MRI scanners use strong magnetic fields and radio waves (radiofrequency energy) to generate images. The signal comes mainly from the protons in fat and water molecules in the body. When interpreted by a trained physician, images from an MRI scan provide information that may be useful in determining a diagnosis. MRI scanners come in different magnet field strengths measured in tesla or “T.” Before today’s clearance, clinical MRI systems were available in field strengths of 3T and below.
The FDA reviewed the Magnetom Terra through the 510(k) premarket clearance pathway. A 510(k) is a premarket submission made to the FDA to demonstrate that a new device is substantially equivalent to a legally marketed predicate device.
The FDA based its clearance on comparison to a predicate device and acquisition of sample clinical images. The agency reviewed the safety of the radiofrequency subsystem through computational modeling, simulations and rigorous experimental validation. The manufacturer also provided data from a comparative study of 35 healthy patients that compared images of the patients using the 7T device and images using the 3T device. Board-certified radiologists reviewed the images and confirmed that the images acquired on the 7T device were of diagnostic quality and, in some cases, an improvement over imaging at the 3T.
The Magnetom Terra is for patients who weigh more than 66 pounds, and is limited to examinations of the head, arms and legs (extremities).
The FDA granted clearance of Magnetom Terra system to Siemens Medical Solutions Inc.