noninvasive mapping
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Author(s):  
Luigi Pannone ◽  
Cinzia Monaco ◽  
Antonio Sorgente ◽  
Pasquale Vergara ◽  
Paul‐Adrian Calburean ◽  
...  

Background The rate of sudden cardiac death (SCD) in Brugada syndrome (BrS) is ≈1%/y. Noninvasive electrocardiographic imaging is a noninvasive mapping system that has a role in assessing BrS depolarization and repolarization abnormalities. This study aimed to analyze electrocardiographic imaging parameters during ajmaline test (AJT). Methods and Results All consecutive epicardial maps of the right ventricle outflow tract (RVOT‐EPI) in BrS with CardioInsight were retrospectively analyzed. (1) RVOT‐EPI activation time (RVOT‐AT); (2) RVOT‐EPI recovery time, and (3) RVOT‐EPI activation‐recovery interval (RVOT‐ARI) were calculated. ∆RVOT‐AT, ∆RVOT‐EPI recovery time, and ∆RVOT‐ARI were defined as the difference in parameters before and after AJT. SCD‐BrS patients were defined as individuals presenting a history of aborted SCD. Thirty‐nine patients with BrS were retrospectively analyzed and 12 patients (30.8%) were SCD‐BrS. After AJT, an increase in both RVOT‐AT [105.9 milliseconds versus 65.8 milliseconds, P <0.001] and RVOT‐EPI recovery time [403.4 milliseconds versus 365.7 milliseconds, P <0.001] was observed. No changes occurred in RVOT‐ARI [297.5 milliseconds versus 299.9 milliseconds, P =0.7]. Before AJT no differences were observed between SCD‐BrS and non SCD‐BrS in RVOT‐AT, RVOT‐EPI recovery time, and RVOT‐ARI ( P =0.9, P =0.91, P =0.86, respectively). Following AJT, SCD‐BrS patients showed higher RVOT‐AT, higher ∆RVOT‐AT, lower RVOT‐ARI, and lower ∆RVOT‐ARI ( P <0.001, P <0.001, P =0.007, P =0.002, respectively). At the univariate logistic regression, predictors of SCD‐BrS were the following: RVOT‐AT after AJT (specificity: 0.74, sensitivity 1.00, area under the curve 0.92); ∆RVOT‐AT (specificity: 0.74, sensitivity 0.92, area under the curve 0.86); RVOT‐ARI after AJT (specificity 0.96, sensitivity 0.58, area under the curve 0.79), and ∆RVOT‐ARI (specificity 0.85, sensitivity 0.67, area under the curve 0.76). Conclusions Noninvasive electrocardiographic imaging can be useful in evaluating the results of AJT in BrS.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Mitul Desai ◽  
Jitendra Sharma ◽  
Adrian L Slusarczyk ◽  
Ashley A Chapin ◽  
Robert Ohlendorf ◽  
...  

Molecular imaging could have great utility for detecting, classifying, and guiding treatment of brain disorders, but existing probes offer limited capability for assessing relevant physiological parameters. Here, we describe a potent approach for noninvasive mapping of cancer-associated enzyme activity using a molecular sensor that acts on the vasculature, providing a diagnostic readout via local changes in hemodynamic image contrast. The sensor is targeted at the fibroblast activation protein (FAP), an extracellular dipeptidase and clinically relevant biomarker of brain tumor biology. Optimal FAP sensor variants were identified by screening a series of prototypes for responsiveness in a cell-based bioassay. The best variant was then applied for quantitative neuroimaging of FAP activity in rats, where it reveals nanomolar-scale FAP expression by xenografted cells. The activated probe also induces robust hemodynamic contrast in nonhuman primate brain. This work thus demonstrates a potentially translatable strategy for ultrasensitive functional imaging of molecular targets in neuromedicine.


2021 ◽  
Author(s):  
MITUL M DESAI ◽  
Jitendra Sharma ◽  
Adrian L Slusarczyk ◽  
Ashley Chapin ◽  
Agata Wisniowska ◽  
...  

Molecular imaging could have great utility for detecting, classifying, and guiding treatment of brain disorders, but existing probes offer limited capability for assessing relevant physiological parameters. Here we describe a potent approach for noninvasive mapping of cancer-associated enzyme activity using a molecular sensor that acts on the vasculature, providing a diagnostic readout via local changes in hemodynamic image contrast. The sensor is targeted at the fibroblast activation protein (FAP), an extracellular dipeptidase and clinically relevant biomarker of brain tumor biology. Optimal FAP sensor variants were identified by screening a series of prototypes for responsiveness in a cell-based bioassay. The best variant was then applied for quantitative neuroimaging of FAP activity in rats, where it reveals nanomolar-scale FAP expression by xenografted tumor cells. The activated probe also induces robust hemodynamic contrast in nonhuman primate brain. This work thus demonstrates a translatable strategy for ultrasensitive functional imaging of molecular targets in neuromedicine.


2021 ◽  
Author(s):  
Eleonora Tamilia ◽  
Margherita A.G. Matarrese ◽  
Georgios Ntolkeras ◽  
P. Ellen Grant ◽  
Joseph R. Madsen ◽  
...  

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Constantin Mork ◽  
Luca Koechlin ◽  
Matthias Streif ◽  
Alexa Hollinger ◽  
Martin Siegemund ◽  
...  

In March 2020, a 64-year-old female with mitral valve insufficiency and persistent atrial fibrillation underwent preoperative noninvasive mapping for developing an ablation strategy. In the computed tomography (CT) scan, typical signs of COVID-19 were described. Since the consecutive polymerase chain reaction (PCR) test was negative, the severely symptomatic patient was planned for urgent surgery. Noninvasive mapping showed that atrial fibrillation was maintained by left atrial structures and pulmonary veins only. On admission day, the preoperative routine COVID-19 PCR test was positive, and after recovery, uneventful mitral valve repair with cryoablation of the left atrium and pulmonary veins was performed. Our case describes the potential benefit of preoperative noninvasive mapping for the development of a surgical ablation strategy, as well as the challenges in managing urgent surgical patients during the COVID-19 pandemic and the corresponding diagnostic relevance of CT.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Namita Ravi ◽  
Kian Waddell ◽  
Wouter-Jan Rappel ◽  
Miguel Rodrigo ◽  
Sanjiv M Narayan

Introduction: It is currently not possible to non-invasively identify patients with atrial fibrillation (AF) who may respond acutely to ablation. We hypothesized that high resolution body surface mapping can identify specific distributions of AF in individuals that predict acute success from ablation. Objective: To correlate 64 lead body surface ECG in AF to acute ablation response and non-invasively identify patients in whom ablation does and does not terminate AF. Method: Fig A shows 64 body surface electrodes in N=17 consecutive AF patients (14 persistent AF, 67 ± 9.06 years). Spectral dominant frequency (DF) from 4096-point FFT, cycle length, AF electrogram amplitude were measured in 200-300 time slices of duration 60s between patches on the body surface representing each atrium (Fig A). Results: Ablation terminated AF in N=7/17 patients (41.2%, Fig. B). Patients with AF termination had more organized AF than those without termination, indicated by lower DF on body surface mapping of the regions corresponding to left (5.00 ± 1.33 vs 5.47 ± 1.30, p < 0.001) and right atrium (5.16 ± 1.50 vs 5.50 ± 1.01, p < 0.003) (Fig C shows composite). DF was stable without statistically significant variations across 20s slices spanning the full minute, supporting interpretability of mechanisms from this analysis (p = NS). Further, AF signal amplitude averaged across left and right atria was lower in patients with AF termination (65.47 ± 36.9 vs 120.13 ± 99.9, p < 0.001) (Fig D). Conclusion: Body surface analysis of AF can non-invasively identify patients in whom ablation may acutely terminate AF. Future studies should determine if this approach can predict who may ultimately achieve long term freedom from AF, and whether body surface signatures are representative enough to be analyzed days prior to the procedure.


eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Jelle Veraart ◽  
Daniel Nunes ◽  
Umesh Rudrapatna ◽  
Els Fieremans ◽  
Derek K Jones ◽  
...  

Axon caliber plays a crucial role in determining conduction velocity and, consequently, in the timing and synchronization of neural activation. Noninvasive measurement of axon radii could have significant impact on the understanding of healthy and diseased neural processes. Until now, accurate axon radius mapping has eluded in vivo neuroimaging, mainly due to a lack of sensitivity of the MRI signal to micron-sized axons. Here, we show how – when confounding factors such as extra-axonal water and axonal orientation dispersion are eliminated – heavily diffusion-weighted MRI signals become sensitive to axon radii. However, diffusion MRI is only capable of estimating a single metric, the effective radius, representing the entire axon radius distribution within a voxel that emphasizes the larger axons. Our findings, both in rodents and humans, enable noninvasive mapping of critical information on axon radii, as well as resolve the long-standing debate on whether axon radii can be quantified.


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