SQUID-detected microtesla MRI in the presence of metal
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- 作者：Michael Mö ; ß ; le ; Song-I Han ; Whittier R. Myers ; Seung-Kyun Lee ; Nathan Kelso ; Michael Hatridge ; Alexander Pines and John Clarke
- 关键词：Magnetic resonance imaging ; SQUID detection ; Low field ; Susceptibility artifacts ; RF screening
- 刊名：Journal of Magnetic Resonance
- 出版年：2006
- 出版时间：March 2006
- 年：2006
- 卷：179
- 期：1
- 页码：146-151
- 全文大小：309 K
文摘
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.