To the Editor:
In the April 2008 issue of The Voice, professor Arnold Wishnia appears surprisingly misinformed. MRI began with the 1971 science paper in which Raymond Damadian, an MD-biophysicist at SUNY Downstate Medical Center, discovered proton T1 and T2 relaxation differences among different normal tissues and between normal and cancerous tissues, and proposed external NMR scanning of live humans based upon these differences.
In a 1972 patent, Damadian described a video-like field-focusing method to scan cross-sections of the human body. This idea was not a dead end nor abandoned. In 1976, Damadian published a cross-sectional image of a mouse with a lung tumor on the front cover of Science. The next year, Damadian published the first whole-body magnetic resonance images of chest and abdomen in normal humans and patients with cancers, using a human-sized superconducting magnet built in his lab at Downstate.
Inspired by Damadian’s science paper, Paul Lauterbur reported the first gradient imaging technique in his 1973 Nature paper (not 1969, as stated by Wishnia). Lauterbur reconstructed two-dimensional images using magnetic field gradients in different directions, imaging two capillary tubes in water, later a clam. Wishnia seems unaware, however, that the “fundamental breakthrough” of getting distance information using magnetic field gradients was independently made 20 years before by Gabillard, in France, and Carr and Purcell (1952 Physics Nobel) at Harvard. They reported that NMR field gradients could generate linear density maps, essential to Lauterbur’s reconstruction technique.
The early imaging methods of Damadian, Lauterbur and Mansfield were all supplanted by spin-warp imaging, developed at University of Aberdeen in 1980. Spin-warp imaging combines phase-encoding with Ernst’s two-dimensional Fourier NMR concept, and with improvements remains the preeminent MRI method today.
Basic to all MRI machines are tissue proton relaxation differences that account for the precise soft-tissue detail unique to MRI. The crucial role of tissue T1 and T2 differences led the U.S. High Court of Patents and Supreme Court in 1997 to uphold Damadian’s 1972 MRI patent. The discovery and development of MRI was clearly multidisciplinary, but Wishnia — like the Nobel Committee for physiology or medicine — has ignored the fundamental biomedical discovery toward which MRI machines are directed to this day.
— Richard Macchia and Paul Dreizen, Brooklyn HSC