The Novel High-accuracy Impedance Tomography Enabled By The Time-of-flight EIT Via CHIRP Current Excitation (CHIRP-EIT)

通过 CHIRP 电流激励的飞行时间 EIT (CHIRP-EIT) 实现新型高精度阻抗断层扫描

• 批准号: EP/X018415/1
• 负责人: Kirill Aristovich
• 金额: $ 25.72万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FX018415%2F1
• 关键词: Novel; accuracy; Impedance; Tomography; Enabled

There is currently no technique that can non-invasively image the functional activity in the brain with sufficient spatial and temporal resolution. In addition, there is a need to have a rapid, precise and portable imaging technique for a variety of medical applications spanning from stroke, where rapid imaging on the back of an ambulance can be life-saving, to conditions like acute respiratory distress syndrome (ARDS) along with a multitude of other acute conditions, treatment of which could be greatly improved with having bedside continuous imaging system.The traditional Electrical Impedance Tomography (EIT) produces images of the internal electrical impedance of a subject using arrays of electrodes (usually 32) placed around the object of interest (e.g. human head). Imperceptible, very low amplitude known current is injected between a pair of electrodes at a time, while electric potentials are measured on the remaining electrodes. By rapid switching of current injections between the possible pairs of electrodes, multiple measurements are made which then can be reconstructed into the image of internal conductivity, the variations of which from the normal values are indicative of various pathologies (e.g. stroke). EIT could potentially be the technique enabling rapid portable and low-cost imaging solutions, but traditionally it results in poor quality blurry images because of the severe theoretical limitations.Time-of-flight EIT can overcome all limitations and result in great improvement in spatial resolution, theoretically providing MRI-quality images with millisecond temporal resolution. The theory relies on the fact that if the current is injected in form of an ideal step function, within the conductive object the current spreads and different paths would take different times to arrive at an opposite electrode. By measuring the voltages at different times of arrival, it is possible to distinguish between the conductivities of all the above different paths, which theoretically will result in a clear high-resolution image. Although the technique is theoretically possible, in practice it was never performed because it is impossible to produce an ideal pulse delta function of a current, and there are additional distortions associated with wave propagation inside the complex conductive object. The above challenges could be solved by employing temporally separated CHIRP excitation patterns (linear frequency modulation). This way of injecting the current is possible to produce in practice, and more importantly, would allow separation between the true time of arrival and all internal distortions within the object. Preliminary calculations showed that these CHIRP pulses would allow resulting images to have 1mm spatial resolution and 1 ms temporal resolution.This will establish a completely new imaging technique with unique capabilities, which has the potential to revolutionise diagnostic medicine and perform life-saving changes in several areas of medical practice. In particular, this will disrupt neurology where there are no other alternative techniques for non-invasive imaging inside the human brain.

目前还没有一种技术能够以足够的空间和时间分辨率非侵入性地成像大脑中的功能活动。此外，需要有一种快速、精确和便携的成像技术，用于从中风到诸如急性呼吸窘迫综合征(ARDS)之类的疾病以及许多其他急性情况的医疗应用，其中救护车背部的快速成像可以挽救生命，具有床边连续成像系统可以极大地改善对这些疾病的治疗。传统的电阻抗断层扫描(EIT)使用放置在感兴趣对象(例如人头)周围的电极阵列(通常为32个)来产生对象的内部电阻抗的图像。在一对电极之间一次注入难以察觉的、幅度非常低的已知电流，而在其余电极上测量电位。通过在可能的电极对之间快速切换电流注入，进行多次测量，然后可以将其重建为内部电导率图像，其与正常值的变化指示各种病理(例如中风)。EIT可能是一种能够实现快速、便携和低成本的成像解决方案的技术，但传统上由于严格的理论限制，它导致图像质量不佳。飞行时间EIT可以克服所有限制并导致空间分辨率的极大提高，理论上提供毫秒时间分辨率的MRI质量图像。这一理论依赖于这样一个事实：如果电流以理想阶跃函数的形式注入，那么在导电物体内，电流扩散和不同的路径将花费不同的时间到达相反的电极。通过测量不同到达时间的电压，可以区分上述所有不同路径的电导率，这在理论上将产生清晰的高分辨率图像。虽然这项技术在理论上是可能的，但实际上它从未被执行过，因为它不可能产生理想的电流脉冲增量函数，并且存在与复杂导电对象内的波传播相关的附加失真。上述挑战可以通过使用时间分离的线性调频激励模式(线性调频)来解决。这种注入电流的方式在实践中是可能产生的，更重要的是，将允许在真实到达时间和物体内部的所有内部扭曲之间进行分离。初步计算表明，这些线性调频脉冲将使产生的图像具有1毫米的空间分辨率和1毫秒的时间分辨率。这将建立一种具有独特能力的全新成像技术，它有可能彻底改变诊断医学，并在医疗实践的几个领域进行拯救生命的改变。特别是，这将扰乱神经学，因为在人脑内没有其他可供选择的非侵入性成像技术。

项目成果

Imaging Circuit Activity in the Rat Brain with Fast Neural EIT and Depth Arrays

使用快速神经 EIT 和深度阵列对大鼠大脑中的电路活动进行成像

• DOI: 10.1109/ner52421.2023.10123878
• 发表时间: 2023
• 作者: Fitchett A

Opinion: the Future of Electrical Impedance Tomography.

• DOI: 10.2478/joeb-2022-0001
• 发表时间: 2022-01
• 期刊: Journal of electrical bioimpedance
• 作者: Aristovich K

Vagus Nerve Selective Stimulation and EIT recording v1

迷走神经选择性刺激和 EIT 记录 v1

• DOI: 10.17504/protocols.io.b42zqyf6
• 发表时间: 2022
• 作者: Ravagli E

Organotopic organization of the porcine mid-cervical vagus nerve.

• DOI: 10.3389/fnins.2023.963503
• 发表时间: 2023
• 期刊: FRONTIERS IN NEUROSCIENCE
• 影响因子: 4.3
• 作者: Thompson, Nicole;Ravagli, Enrico;Mastitskaya, Svetlana;Iacoviello, Francesco;Stathopoulou, Thaleia-Rengina;Perkins, Justin;Shearing, Paul R.;Aristovich, Kirill;Holder, David
• 通讯作者: Holder, David

The Feasibility of Fast Neural Magnetic Detection Electrical Impedance Tomography: A Modelling Study

快速神经磁检测电阻抗断层扫描的可行性：建模研究

• DOI: 10.1109/ner52421.2023.10123778
• 发表时间: 2023
• 作者: Mason K