Silica-coated bismuth sulfide nanorods as multimodal contrast agents for a non-invasive visualization of the gastrointestinal tract

In this paper we have prepared Bi2S3@SiO2 nanorods designed as binary contrast agents for a non-invasive and real-time visualization of the gastrointestinal tract.

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Targeting Contrast Agents With Peak Near-Infrared-II (NIR-II) Fluorescence Emission for Non-invasive Real-Time Direct Visualization of Thrombosis

Frontiers in Molecular Biosciences ◽

10.3389/fmolb.2021.670251 ◽

2021 ◽

Vol 8 ◽

Author(s):

Kenneth S. Hettie

Keyword(s):

Contrast Agents ◽

Real Time ◽

Near Infrared ◽

Fluorescence Emission ◽

Therapeutic Window ◽

Direct Visualization ◽

Spatiotemporal Resolution ◽

Accurate Identification ◽

Non Invasive ◽

Nirf Imaging

Thrombosis within the vasculature arises when pathological factors compromise normal hemostasis. On doing so, arterial thrombosis (AT) and venous thrombosis (VT) can lead to life-threatening cardio-cerebrovascular complications. Unfortunately, the therapeutic window following the onset of AT and VT is insufficient for effective treatment. As such, acute AT is the leading cause of heart attacks and constitutes ∼80% of stroke incidences, while acute VT can lead to fatal therapy complications. Early lesion detection, their accurate identification, and the subsequent appropriate treatment of thrombi can reduce the risk of thrombosis as well as its sequelae. As the success rate of therapy of fresh thrombi is higher than that of old thrombi, detection of the former and accurate identification of lesions as thrombi are of paramount importance. Magnetic resonance imaging, x-ray computed tomography (CT), and ultrasound (US) are the conventional non-invasive imaging modalities used for the detection and identification of AT and VT, but these modalities have the drawback of providing only image-delayed indirect visualization of only late stages of thrombi development. To overcome such limitations, near-infrared (NIR, ca. 700–1,700 nm) fluorescence (NIRF) imaging has been implemented due to its capability of providing non-invasive real-time direct visualization of biological structures and processes. Contrast agents designed for providing real-time direct or indirect visualization of thrombi using NIRF imaging primarily provide peak NIR-I fluorescence emission (ca. 700–1,000 nm), which affords limited tissue penetration depth and suboptimal spatiotemporal resolution. To facilitate the enhancement of the visualization of thrombosis via providing detection of smaller, fresh, and/or deep-seated thrombi in real time, the development of contrast agents with peak NIR-II fluorescence emission (ca. 1000–1,700 nm) has been recently underway. Currently, however, most contrast agents that provide peak NIR-II fluorescence emissions that are purportedly capable of providing direct visualization of thrombi or their resultant occlusions actually afford only the indirect visualization of such because they only provide for the (i) measuring of the surrounding vascular blood flow and/or (ii) simple tracing of the vasculature. These contrast agents do not target thrombi or occlusions. As such, this mini review summarizes the extremely limited number of targeting contrast agents with peak NIR-II fluorescence emission developed for non-invasive real-time direct visualization of thrombosis that have been recently reported.

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Dynamic tracking of a magnetic micro-roller using ultrasound phase analysis

10.21203/rs.3.rs-366904/v2 ◽

2021 ◽

Author(s):

Stefano Pane ◽

Veronica Iacovacci ◽

Mohammad Hasan Dad Ansari ◽

Arianna Menciassi

Keyword(s):

Real Time ◽

Average Error ◽

Contrast Resolution ◽

Low Contrast ◽

Non Invasive ◽

Dynamic Tracking ◽

Fine Control ◽

Real Time Visualization ◽

Acoustic Phase

Abstract Microrobots (MRs) have attracted significant interest for their potentialities in diagnosis and non-invasive intervention in hard-to-reach body areas. Fine control of biomedical MRs requires real-time feedback on their position and configuration. Ultrasound (US) imaging stands as a mature and advantageous technology for MRs tracking, but it suffers from disturbances due to low contrast resolution. To overcome these limitations and make US imaging suitable for monitoring and tracking MRs, we propose a US contrast enhancement mechanism for MR visualization in echogenic backgrounds (e.g., tissue). Our technique exploits the specific acoustic phase modulation produced by the MR characteristic motions. By applying this principle, we performed real-time visualization and position tracking of a magnetic MR rolling on a lumen boundary, both in static flow and opposing flow conditions, with an average error of 0.25 body-lengths. Overall, the reported results unveil countless possibilities to exploit the proposed approach as a robust feedback strategy for monitoring and tracking biomedical MRs in-vivo.

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Near Infra-Red Labelling and Tracking of Transplanted Corneal Endothelial Graft

10.21203/rs.3.rs-244628/v1 ◽

2021 ◽

Author(s):

Maninder Bhogal ◽

Heng-Pei Ang ◽

Shu-Jun Lin ◽

Lwin Chan ◽

Khadijah Adnan ◽

...

Keyword(s):

Real Time ◽

Corneal Transplantation ◽

Specular Microscopy ◽

Post Transplantation ◽

In Vivo Evaluation ◽

Non Invasive ◽

Real Time Visualization ◽

Donor Graft

Abstract Following corneal transplantation, there is an initial decline in corneal endothelial cells (CECs) following graft preparation and surgery. Monitoring post-transplantation is only possible months after surgery by specular microscopy, which has a limited field of view. We have developed a labelling approach using 1,1’-dioctadecyl-3,3,3’,3’-tetramethylindotricarbocyanine iodide (DIR) dye solution, that enabled tracking of labelled CECs in vivo for at least one month. Initial in vitro optimization of dye concentration, cellular toxicity and real-time cell migration was assessed using propagated primary CECs. Subsequent in vivo evaluation of cellular labelling was assessed within a rabbit wound healing model. Finally, real-time visualization of human cadaver donor tissue incubated in DIR transplanted into rabbits was achieved using the Heidelberg Spectralis. Results revealed detectable fluorescence increased with concentration to a plateau of 100µg/ml, with no toxicity of CECs at any concentration evaluated. DIR-labelled CECs were detectable in vivo upto 1 month, and transplanted labelled donor graft could be visualized and were trackable in vivo. Acute endothelial rejection in 1 rabbit was evidenced by detectable DIR positive cells within the anterior chamber. DIR imaging allowed for detailed imaging of the transplanted corneal endothelium, and enabled non-invasive observation of the corneal endothelial morphology following transplantation.

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TAAC - TMS Adaptable Auditory Control: a universal tool to mask TMS click

10.1101/2021.09.08.459439 ◽

2021 ◽

Cited By ~ 2

Author(s):

S. Russo ◽

S. Sarasso ◽

G.E. Puglisi ◽

D. Dal Palù ◽

A. Pigorini ◽

...

Keyword(s):

Open Source ◽

Real Time ◽

Auditory Evoked Potentials ◽

Individual Subject ◽

Non Invasive ◽

Frequency Domains ◽

Masking Noise ◽

Real Time Visualization ◽

Discharge Noise ◽

The Individual

AbstractBackgroundCoupling transcranial magnetic stimulation with electroencephalography (TMS-EEG) allows recording the EEG response to a direct, non-invasive cortical perturbation. However, obtaining a genuine TMS-evoked EEG potential requires controlling for several confounds, among which a main source is represented by the auditory evoked potentials (AEPs) associated to the TMS discharge noise (TMS click). This contaminating factor can be in principle prevented by playing a masking noise through earphones.New methodHere we release TMS Adaptable Auditory Control (TAAC), a highly flexible, open-source, Matlab®-based interface that generates in real-time customized masking noises. TAAC creates noises starting from the stimulator-specific TMS click and tailors them to fit the individual, subject-specific click perception by mixing and manipulating the standard noises in both time and frequency domains.ResultsWe showed that TAAC allows us to provide standard as well as customized noises able to effectively and safely mask the TMS click.Comparison with existing methodsHere, we showcased two customized noises by comparing them to two standard noises previously used in the TMS literature (i.e., a white noise and a noise generated from the stimulator-specific TMS click only). For each, we quantified the Sound Pressure Level (SPL; measured by a Head and Torso Simulator - HATS) required to mask the TMS click in a population of 20 healthy subjects. Both customized noises were effective at safe (according to OSHA and NIOSH safety guidelines), lower SPLs with respect to standard noises.ConclusionsAt odds with previous methods, TAAC allows creating effective and safe masking noises specifically tailored on each TMS device and subject. The combination of TAAC with tools for the real-time visualization of TEPs can help control the influence of auditory confounds also in non-compliant patients. Finally, TAAC is a highly flexible and open-source tool, so it can be further extended to meet different experimental requirements.

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Dynamic tracking of a magnetic micro-roller using ultrasound phase analysis

Scientific Reports ◽

10.1038/s41598-021-02553-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Stefano Pane ◽

Veronica Iacovacci ◽

Mohammad Hasan Dad Ansari ◽

Arianna Menciassi

Keyword(s):

Real Time ◽

Average Error ◽

Contrast Resolution ◽

Low Contrast ◽

Non Invasive ◽

Dynamic Tracking ◽

Fine Control ◽

Real Time Visualization ◽

Acoustic Phase

AbstractMicrorobots (MRs) have attracted significant interest for their potentialities in diagnosis and non-invasive intervention in hard-to-reach body areas. Fine control of biomedical MRs requires real-time feedback on their position and configuration. Ultrasound (US) imaging stands as a mature and advantageous technology for MRs tracking, but it suffers from disturbances due to low contrast resolution. To overcome these limitations and make US imaging suitable for monitoring and tracking MRs, we propose a US contrast enhancement mechanism for MR visualization in echogenic backgrounds (e.g., tissue). Our technique exploits the specific acoustic phase modulation produced by the MR characteristic motions. By applying this principle, we performed real-time visualization and position tracking of a magnetic MR rolling on a lumen boundary, both in static flow and opposing flow conditions, with an average error of 0.25 body-lengths. Overall, the reported results unveil countless possibilities to exploit the proposed approach as a robust feedback strategy for monitoring and tracking biomedical MRs in-vivo.

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Magnetic resonance imaging for pathobiological assessment and interventional treatment of the coronary arteries

European Heart Journal Supplements ◽

10.1093/eurheartj/suaa009 ◽

2020 ◽

Vol 22 (Supplement_C) ◽

pp. C46-C56

Author(s):

Timo Heidt ◽

Simon Reiss ◽

Thomas Lottner ◽

Ali C Özen ◽

Christoph Bode ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Contrast Agents ◽

Real Time ◽

Vessel Wall ◽

Resonance Imaging ◽

X Ray ◽

Non Invasive ◽

Iodinated Contrast ◽

Iodinated Contrast Agents

Abstract X-ray-based fluoroscopy is the standard tool for diagnostics and intervention in coronary artery disease. In recent years, computed tomography has emerged as a non-invasive alternative to coronary angiography offering detection of coronary calcification and imaging of the vessel lumen by the use of iodinated contrast agents. Even though currently available invasive or non-invasive techniques can show the degree of vessel stenosis, they are unable to provide information about biofunctional plaque properties, e.g. plaque inflammation. Furthermore, the use of radiation and the necessity of iodinated contrast agents remain unfavourable prerequisites. Magnetic resonance imaging (MRI) is a radiation-free alternative to X-ray which offers anatomical and functional imaging contrasts fostering the idea of non-invasive biofunctional assessment of the coronary vessel wall. In combination with molecular contrast agents that target-specific epitopes of the vessel wall, MRI might reveal unique plaque properties rendering it, for example, ‘vulnerable and prone to rupture’. Early detection of these lesions may allow for early or prophylactic treatment even before an adverse coronary event occurs. Besides diagnostic imaging, advances in real-time image acquisition and motion compensation now provide grounds for MRI-guided coronary interventions. In this article, we summarize our research on MRI-based molecular imaging in cardiovascular disease and feature our advances towards real-time MRI-based coronary interventions in a porcine model.

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Ultrasound-guided navigation of a magnetic microrobot using acoustic phase analysis

10.21203/rs.3.rs-366904/v1 ◽

2021 ◽

Author(s):

Stefano Pane ◽

Veronica Iacovacci ◽

Mohammad Hasan Dad Ansari ◽

Arianna Menciassi

Keyword(s):

Real Time ◽

Closed Loop ◽

Average Error ◽

Low Contrast ◽

Loop Control ◽

Non Invasive ◽

Fine Control ◽

Real Time Visualization ◽

Acoustic Phase

Abstract Microrobots (MRs) have attracted significant interest for their potentialities in diagnosis and non-invasive intervention in hard-to-reach body areas. Fine control of biomedical MRs requires real-time feedback on their position and configuration. Ultrasound (US) imaging stands as a mature and advantageous technology for MRs tracking, but it suffers from disturbances due to low contrast resolution. To overcome these limitations and make US imaging suitable for closed-loop MR control, we propose a US contrast enhancement mechanism for MR visualization in heterogeneous and dynamic backgrounds (e.g., tissue). Our technique exploits the specific acoustic phase modulation produced by the MR characteristic motions. By applying this principle, we performed real-time visualization and position tracking of a magnetic MR rolling on a lumen boundary, both in static flow and opposing flow conditions, with an average error of 0.25 body-lengths. Overall, the reported results unveil countless possibilities to exploit the proposed approach as a robust feedback strategy for closed-loop control of medical MRs in-vivo.

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