Dohi Tetsuji, Murashige Kousuke
Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan.
Micromachines (Basel). 2016 Apr 21;7(4):67. doi: 10.3390/mi7040067.
This paper reports on a micro saddle coil for local high-resolution magnetic resonance imaging (MRI) fabricated by embedding a flexible coil pattern into a polydimethyilsiloxane (PDMS) tube. We can change the sensitivity of the micro coil by deforming the shape of the coil from a saddle-shaped mode to a planar-shaped mode. The inductance, the resistance, and the Q-factor of the coil in the saddle-shaped mode were 2.45 μH, 3.31 Ω, and 39.9, respectively. Those of the planar-shaped mode were 3.07 μH, 3.92 Ω, and 42.9, respectively. In MRI acquired in saddle-shaped mode, a large visible area existed around the coil. Although the sensitive area was considerably reduced in the planar-shaped mode, clear MRI images were obtained. The signal-to-noise ratios (SNR) of the saddle-shaped and planar-shaped modes were 194.9 and 505.9, respectively, at voxel size of 2.0 × 2.0 × 2.0 mm³ and 11.7 and 37.4, respectively, at voxel size of 0.5 × 0.5 × 1.0 mm³. The sensitivity of the saddle-shaped and the planar-shaped modes were about 3 times and 10 times higher, respectively, than those of the medical head coil at both voxel sizes. Thus, the micro saddle coil enabled large-area imaging and highly sensitive imaging by switching the shape of the coil.
本文报道了一种用于局部高分辨率磁共振成像（MRI）的微鞍形线圈，该线圈通过将柔性线圈图案嵌入聚二甲基硅氧烷（PDMS）管中制成。我们可以通过将线圈形状从鞍形模式变形为平面模式来改变微线圈的灵敏度。鞍形模式下线圈的电感、电阻和品质因数分别为2.45μH、3.31Ω和39.9。平面模式下的分别为3.07μH、3.92Ω和42.9。在以鞍形模式采集的MRI中，线圈周围存在较大的可见区域。尽管在平面模式下敏感区域显著减小，但仍获得了清晰的MRI图像。在体素大小为2.0×2.0×2.0mm³时，鞍形模式和平坦模式的信噪比（SNR）分别为194.9和505.9，在体素大小为0.5×0.5×1.0mm³时，分别为11.7和37.4。在这两种体素大小下，鞍形模式和平坦模式的灵敏度分别比医用头部线圈高约3倍和10倍。因此，微鞍形线圈通过切换线圈形状实现了大面积成像和高灵敏度成像。
