Optimizing accuracy and precision of micro-coil localization in active-MR tracking

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• 作者：Barret Robert Daniels^a ; ^b ; ^{barret.daniels@cchmc.org" class="auth_mail" title="E-mail the corresponding author} ; Ronald Pratt^a ; Randy Giaquinto^a ; ^b ; Charles Dumoulin^a ; ^b
• 关键词：MR tracking ; Active device tracking ; Micro-transmit tracking ; Centroid pixel method ; Interventional MRI ; MR catheter tracking
• 刊名：Magnetic Resonance Imaging
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：34
• 期：3
• 页码：289-297
• 全文大小：1603 K

文摘

To examine whether a centroid peak detection algorithm and micro-transmit tracking improve the accuracy and precision of active-MR tracking when combined with previously published strategies of Hadamard Multiplexing and Phase-field Dithering.

Materials and methods

The dipole magnetic field of a solenoid tracking coil was modeled and MR spin excitation using both a uniform body coil and the tracking coil was simulated for 5329 orientations of the solenoid coil with respect to B₀. A lumenless micro-coil was built onto a rotation platform and MR-tracking accuracy and precision were experimentally assessed for 576 orientations within a 1.5-T MRI scanner. Peak identification strategies (i.e. maximum pixel detection and the centroid pixel method) and transmit modes (body transmit and micro-transmit tracking) were employed and localization accuracy was assessed for each orientation in both simulation and experimentation.

Results

The simultaneous use of the centroid pixel method, micro-transmit tracking, Phase-field Dithering, and Hadamard Multiplexing resulted in high MR tracking accuracy and precision: 0.52 ± 0.41 mm and 0.34 mm respectively. Furthermore, all four methods combined offered a tracking error less than the size of the micro-coil, despite the lack of a signal source within the micro-coil.

Conclusions

Micro-transmit tracking and the centroid pixel method improve MR tracking accuracy and precision when combined with Phase-field Dithering and Hadamard Multiplexing compared to using Phase-field Dithering and Hadamard Multiplexing alone.