Parallel MRI at microtesla fields
| dc.creator | Zotev, V. S. | |
| dc.creator | Volegov, P. L. | |
| dc.creator | Matlashov, A. N. | |
| dc.creator | Espy, M. A. | |
| dc.creator | Mosher, J. C. | |
| dc.creator | Kraus Jr, R. H. | |
| dc.date | 2007-01-16 | |
| dc.date | 2008-03-28 | |
| dc.date.accessioned | 2026-07-07T11:36:45Z | |
| dc.date.available | 2026-07-07T11:36:45Z | |
| dc.description | Parallel imaging techniques have been widely used in high-field magnetic resonance imaging (MRI). Multiple receiver coils have been shown to improve image quality and allow accelerated image acquisition. Magnetic resonance imaging at ultra-low fields (ULF MRI) is a new imaging approach that uses SQUID (superconducting quantum interference device) sensors to measure the spatially encoded precession of pre-polarized nuclear spin populations at microtesla-range measurement fields. In this work, parallel imaging at microtesla fields is systematically studied for the first time. A seven-channel SQUID system, designed for both ULF MRI and magnetoencephalography (MEG), is used to acquire 3D images of a human hand, as well as 2D images of a large water phantom. The imaging is performed at 46 microtesla measurement field with pre-polarization at 40 mT. It is shown how the use of seven channels increases imaging field of view and improves signal-to-noise ratio for the hand images. A simple procedure for approximate correction of concomitant gradient artifacts is described. Noise propagation is analyzed experimentally, and the main source of correlated noise is identified. Accelerated imaging based on one-dimensional undersampling and 1D SENSE (sensitivity encoding) image reconstruction is studied in the case of the 2D phantom. Actual 3-fold imaging acceleration in comparison to single-average fully encoded Fourier imaging is demonstrated. These results show that parallel imaging methods are efficient in ULF MRI, and that imaging performance of SQUID-based instruments improves substantially as the number of channels is increased. | |
| dc.description | 12 pages, 7 figures - accepted by JMR | |
| dc.identifier | https://arxiv.org/abs/physics/0701188 | |
| dc.identifier | http://arxiv.org/abs/physics/0701188 | |
| dc.identifier | J.Magn.Resonance192:197,2008 | |
| dc.identifier | doi:10.1016/j.jmr.2008.02.015 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/199024 | |
| dc.subject | Medical Physics | |
| dc.subject | Instrumentation and Detectors | |
| dc.title | Parallel MRI at microtesla fields | |
| dc.type | text |