Adaptive and Wireless Recordings of Electrophysiological Signals during Concurrent Magnetic Resonance Imaging

Mandal, Ranajay; Babaria, Nishant; Cao, Jiayue; Li, Zhong‐Ming

doi:10.1101/259762

Cited by 2 publications

(4 citation statements)

References 44 publications

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“…The in vivo ECG experiment is conducted to test the device for monitoring a reliable and well-known bio-signal inside vs. outside the MRI[62,68]. Outside of the MRI, the ECG signal is recorded by the device, as well as a benchtop amplifier (Cp511, Grass Instruments).…”

Section: Resultsmentioning

confidence: 99%

“…To improve signal to noise ratio (SNR), we placed the electrodes directly on the skull of the animals and secured them with medical grade epoxy. For ECG recordings, we used radiolucent pin electrodes [61] (SA Instruments, Inc., Stony Brook, NY) and placed them in Einthoven's Triangle formation [62][63][64]. To monitor esophageal pH, we placed a pH probe, containing 1-2 electrodes, at the bottom of the esophagus according to a previous study [20].…”

Section: Electrodes and Transducersmentioning

confidence: 99%

“…Bio-signal recording during concurrent MRI is challenging due to the large EMI artifacts generated by the MRI scanner. We developed a multichannel recording platform based on earlier designs [71,72] that minimized such imaging artifacts and allowed us to record EEG, ECG, chest plethysmography and esophageal pH while performing fast MRI scans of the GI tract. The system allowed us to monitor seizure progression, cardiorespiratory distress, and any stomach fluid movement during the study.…”

Section: Multimodal Imaging For Evaluating Esophagusmentioning

confidence: 99%

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Utilizing Multimodal Imaging to Visualize Potential Mechanism for Sudden Death in Epilepsy

Mandal¹,

Budde²,

Lawlor³

et al. 2021

Preprint

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Sudden death in epilepsy, or SUDEP, is a fatal condition that accounts for more than 4000 deaths each year. Limited clinical and preclinical data on sudden death suggests critical contributions from autonomic, cardiac, and respiratory pathways. Recent animal (rat) studies on kainic acid induced seizure models explored a potential mechanism for such sudden and severe cardiorespiratory dysregulation being linked to acid reflux induced laryngospasm. Here, we expand on those previous investigations and utilize a multimodal approach to provide visual evidence of acid reflux-initiated laryngospasm and subsequent fatal cardiorespiratory distress in seizing rats.We used systemic kainic acid to acutely induce seizure activity in Long Evans rats, under urethane anesthesia. We recorded electroencephalography (EEG), electrocardiography (ECG), chest plethysmography and esophageal pH signals during simultaneous fast MRI scans of the rat stomach and esophagus. MRI images, in conjunction with electrophysiology data were used to identify seizure progression, stomach acid movement up the esophagus, cardiorespiratory changes, and sudden death.In all cases of sudden death, esophageal pH recordings alongside MRI images visualized stomach acid movement up the esophagus. Severe cardiac (ST segment elevation), respiratory (intermittent apnea) and brain activity (EEG narrowing due to hypoxia) changes were observed only after acid reached the larynx, which strongly suggests onset of laryngospasm following acid reflux. Additionally, absence of stomach acid in the esophagus of animals that survived acute seizure, provided evidence of a causal relationship between acid reflux and sudden death. The complimentary information coming from electrophysiology and fast MRI scans provided insight into the mechanism of esophageal reflux, laryngospasm, obstructive apnea, and subsequent sudden death in seizing animals. The results carry clinical significance as they outline a potential mechanism that may be relevant to SUDEP in humans.

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Section: Resultsmentioning

confidence: 99%

Section: Electrodes and Transducersmentioning

confidence: 99%

Section: Multimodal Imaging For Evaluating Esophagusmentioning

confidence: 99%

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Utilizing Multimodal Imaging to Visualize Potential Mechanism for Sudden Death in Epilepsy

Mandal¹,

Budde²,

Lawlor³

et al. 2021

Preprint

Self Cite

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“…Additionally, the large current delivery capabilities of the stimulator are well suited for additional modes of stimulation like optical [52] or mechanical stimulation [53], [54] during concurrent imaging studies. Another interesting approach may be to integrate a low power recording system [55], [56] with the power harvesting and stimulation unit described here. These integrative systems can enable simultaneous recording of biopotentials, electrical stimulation and imaging (MRI and fMRI) for closed loop image guided neuromodulation.…”

Section: Future Development and Applicationmentioning

confidence: 99%

MRI Powered and Triggered Current Stimulator for Concurrent Stimulation and MRI

Mandal

Babaria²,

Cao

et al. 2019

Preprint

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Bioelectric stimulation during concurrent magnetic resonance imaging (MRI) is of interest to basic and translational studies. However, existing stimulation systems often interfere with MRI, are difficult to use or scale up, have limited efficacy, or cause safety concerns. To address these issues, we present a novel device capable of supplying current stimulation synchronized with MRI while being wirelessly powered by the MRI gradient fields. Results from testing it with phantoms and live animals in a 7 Tesla small-animal MRI system suggest that the device is able to harvest up to 72 (or 18) mW power during typical echo-planar imaging (or fast low angle shot imaging) and usable for stimulating peripheral muscle or nerve to modulate the brain or the gut, with minimal effects on MRI image quality. As a compact and standalone system, the plug-and-play device is suitable for animal research and merits further development for human applications. Introduction:Neurostimulation, e.g. Deep Brain Stimulation (DBS), Vagal Nerve Stimulation (VNS), Spinal Cord Stimulation (SCS), has been widely used to treat Parkinson's disease [1], dystonia [2], [3], epilepsy [4], [5], and intractable pain syndrome [6], [7], to name a few examples. It has also been increasingly recognized that magnetic resonance imaging (MRI) can guide neuromodulation and improve its efficacy, especially if neural stimulation and imaging are performed simultaneously [8]-[12]. However, concurrent stimulation and MRI is non-trivial. A conventional stimulation device may jeopardize patient safety and degrade imaging quality [13], while MRI may interfere with the device and corrupt its function [14]-[16], due to the strong and varying magnetic fields during MRI [17]. In addition, a device often requires long cables to connect to a power source or receive external triggers, where-as such cables may perturb the magnetic fields and degrade image acquisition [18], [19]. Widely used methods for simultaneous MRI and neuromodulation involve non-MR-safe stimulators, which are placed outside the MRI room and connected to the subject using long twisted cables [20]-[23]. The longer stimulation cables sometime pick up fast gradient magnetic fields and lead to unwanted electrical stimulation [24][25]. Few studies include conditionally MRsafe stimulators placed near the MRI bore with shorter cables and RF filtering [26]-[28][29].However, such setups are difficult to scale up, since more stimulation channels would require more cables and RF filtering circuits and amount to an increasingly bulky and complex system.The system also causes patient discomfort, prolongs preparation time, affects imaging quality, especially at a high field (7 Tesla or above) [30].

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Adaptive and Wireless Recordings of Electrophysiological Signals during Concurrent Magnetic Resonance Imaging

Cited by 2 publications

References 44 publications

Utilizing Multimodal Imaging to Visualize Potential Mechanism for Sudden Death in Epilepsy

Utilizing Multimodal Imaging to Visualize Potential Mechanism for Sudden Death in Epilepsy

MRI Powered and Triggered Current Stimulator for Concurrent Stimulation and MRI

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