Magnetic Resonance Imaging (MRI)

Scientists and clinicians greeted the introduction of fMRI with enthusiasm. They immediately saw the benefits of a technique that is noninvasive, does not use ionizing radiation, and has higher temporal and spatial resolution than PET imaging, and in which there was no limit to the number of images that could be safely acquired from an individual. fMRI showed potential for a host of applications, including advancing psychology and psychiatry, presurgical mapping of the brain and imaging focal seizures.

After completing his experiments with functional imaging with endogenous contrast, Ken Kwong submitted an abstract describing the “work in progress” movies of brain activation to the 10th annual meeting of the Society for Magnetic Resonance in Medicine (SMRM), to be held in San Francisco in August 1991. But the abstract was lost in the mail, leaving the announcement of the discovery of fMRI to a mention in a paper presentation session by Bernice Hoppel and the brief video in the plenary lecture by Thomas Brady. Even this brief glimpse of the results made an impact, though.

This system comprises a 15T (620 MHz) Magnex 130-mm diameter horizontal magnet and Resonance Research gradient and shim coils interfaced to a Siemens clinical console with 32 receiver channels; installation of the system is currently ongoing, and is nearing completion. A quadrature birdcage coil and multichannel frequency converter to interface between the console (operating at about 102 MHz) and the magnet (620 MHz) were developed in-house.

The 9.4T (400 MHz proton frequency) 21-cm diameter horizontal bore magnet (Magnex Scientific) uses a Bruker Avance console, and is capable of multinuclear imaging and spectroscopy of small animals (rats and mice). Capabilities include high-quality high-resolution anatomical and functional imaging, using a wide variety of contrast mechanisms (T1, T2, diffusion, perfusion), together with multi-shot 2D and 3D sequences, single shot EPI, localized spectroscopy and spectroscopic imaging.

Magnetic resonance imaging is the gold standard in diagnostic imaging.