SQUID-detected microtesla MRI in the presence of metal.
In magnetic resonance imaging performed at fields of 1 T and above, the presence of a metal insert can distort the image because of susceptibility differences within the sample and modification of the radiofrequency fields by screening currents. Furthermore, it is not feasible to perform nuclear magnetic resonance (NMR) spectroscopy or acquire a magnetic resonance image if the sample is enclosed in a metal container. Both problems can be overcome by substantially lowering the NMR frequency. Using a microtesla imaging system operating at 2.8 kHz, with a superconducting quantum interference device as the signal detector, we have obtained distortion-free images of a phantom containing a titanium bar and three-dimensional images of an object enclosed in an aluminum can; in both cases high-field images are inaccessible.
Mössle
Michael
M
Department of Physics, University of California at Berkeley, Lawrence Berkeley National Laboratory, CA 94720 7300, USA. moessle@lbl.gov
Han
Song-I
SI
Myers
Whittier R
WR
Lee
Seung-Kyun
SK
Kelso
Nathan
N
Hatridge
Michael
M
Pines
Alexander
A
Clarke
John
J
D000535:Aluminum; D016477:Artifacts; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008280:Magnetics; D008670:Metals; D019736:Prostheses and Implants; D014025:Titanium
D008670:Metals; D000535:Aluminum; D014025:Titanium