Better Imaging for Disease Detection

Optics and photonics researchers have developed two new biomedical imaging technologies that improve brain scans and mammography in 3D.

An international team of physicists and neuroscientists is making MRI brain scans more than seven times faster than currently possible by combining two technical improvements invented in the past decade that separately boosted scanning speeds two to four times over what was already the fastest MRI technique, echo planar imaging (EPI).

U.S. researchers from University of California, Berkeley, and University of Minnesota, along with colleagues at Oxford University (UK), reported that their technique allows for full 3D brain scans in less than half a second, compared to the typical two to three seconds. They describe their method in "Multiplexed Echo Planar Imaging for Sub-Second Whole Brain fMRI and Fast Diffusion Imaging," published in the journal PLoS ONE in December 2010.

"When we made the first images, it was unbelievable how fast we were going," said first author David Feinberg, a physicist and adjunct professor in UC Berkeley's Helen Wills Neuroscience Institute and president of the company Advanced MRI Technologies in Sebastopol, CA.

"It was like stepping out of a prop plane into a jet plane. It was that magnitude of difference."

For neuroscience, in particular, fast scans are critical for capturing the dynamic activity in the brain. "When a functional MRI study of the brain is performed, about 30 to 60 images covering the entire 3-D brain are repeated hundreds of times like the frames of a movie but, with fMRI, a 3D movie," Feinberg said. "By multiplexing the image acquisition for higher speed, a higher frame rate is achieved for more information in a shorter period of time."

In addition to broadly advancing the field of neural-imaging, the discovery will impact the Human Connectome Project, a National Institutes of Health-funded program designed to map the connections of the human brain through functional MRI and structural MRI scans of 1200 healthy adults.

"At the time we submitted our grant proposal for the Human Connectome Project, we had aspirations of acquiring better quality data from our study participants, so this discovery is a tremendous step in helping us accomplish the goals of the project," said David Van Essen, a neurobiologist at Washington University and co-leader of the project.

"It's vital that we get the highest quality imaging data possible, so we can infer accurately the brain's circuitry - how connections are established, and how they perform."

The faster scans are made possible by combining two technical improvements invented in the past decade that separately boosted scanning speeds two to four times over what was already the fastest MRI technique, echo planar imaging (EPI). Physical limitations of each method prevented further speed improvements, "but together their image accelerations are multiplied," Feinberg said.

The team can now obtain brain scans substantially faster than the time reductions reported in their paper and many times faster than the capabilities of today's machines.

FDA approves 3D mammography device

On the breast cancer screening front, the U.S. Food and Drug Administration approved in January the first x-ray mammography device that provides 3D images of the breast.

The Selenia Dimensions System, made by Hologic, is based on digital tomosynthesis, a technology that can see through overlapping tissue often obscured in traditional 2D scans. This allows radiologists to accurately differentiate abnormalities from normal tissue.

Clinical trials showed a 7% improvement in radiologists' confidence in ruling out cancer without recalling the patient for further study. Other benefits include improved lesion and margin visibility.

Read more about these advancements in the SPIE Newsroom and the SPIE Digital Library

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