Ultrafast Magnetic Gradients Eliminate MRI Nerve Stimulation

Stanley Fricke of the Children’s National Medical Center (Washington DC, USA). “Our ultimate goal,” said Dr. Fricke, “is to image small children in seconds rather than minutes. In this way children will not need to be anesthetized prior to imaging.”

The findings were published May 7, 2012, in the peer journal Medical Physics, Earlier attempts to considerably accelerate MRI failed because gradient pulse sequences can cause twitching or more serious nerve stimulation. To prevent such unwanted and potentially dangerous side effects, the US Food and Drug Administration (FDA) and European regulators put in place restrictions on gradient strength and speed, based on older clinical studies that used relatively slow gradients. The new medical physics study employed pulse sequences with rise times 100 times faster than conventional MRI to validate that nerve stimulation could be eliminated by employing ultrafast magnetic gradients.

According to Dr. Fricke, “the old speed limits may need to be reviewed in light of this new data. The new technology could lead to the adoption of MRI as a first-line method of assessing coronary artery disease, improve high-resolution brain mapping, and implement low-cost dental MRI as a potential nonionizing-radiation alternative to X-rays.”

Dr. Benjamin Shapiro, a team member from University of Maryland’s Fischell department of bioengineering (College Park, USA), has proposed using the high gradients with magnetic nanoparticles to improve image-guided minimally invasive therapy.

The ground-breaking study, funded by the US National Institute of Neurological Disorders and Stroke and the National Heart Lung and Blood Institute (both based in Bethesda, MD, USA), defies years of traditional wisdom in the MRI field. Increasing the speed and magnitude of gradients has been a long-sought goal in the medical imaging community. “Prior clinical studies concluded that nerve stimulation prevented the use of strong gradient pulse sequences,” commented Dr. Fricke. He categorized the speed breakthrough as both metaphorically and literally “breaking the sound barrier,” since the higher MRI frequency is beyond human hearing ability.

The ultra-strong and extremely fast gradient technology to break the MRI sound barrier was created with cutting-edge instrumentation created by Weinberg Medical Physics, LLC (Bethesda, MD, USA), an R&D lab. In May 2012, the company was granted a patent for the nonstimulating magnetic gradient generation technique.

Related Links:
Children’s National Medical Center
Weinberg Medical Physics