Impact of surrounding tissue on conductance measurement of coronary and peripheral lumen area

Choi, Hyo Won; Jansen, Benjamin; Zhang, Zhen-Du; Kassab, Ghassan S.

doi:10.1098/rsif.2012.0188

Cited by 5 publications

(9 citation statements)

References 38 publications

(83 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Methodsmentioning

confidence: 99%

“…The total thickness of surrounding tissue L T was assumed to be 3.5 cm based on our previous study [6]. The depth of a blood vessel L D was modeled as 12.7–15.7 mm which is commensurate with the deepest limit of blood vessel depths modeled previously [6] that can have the most unfavorable impact on the measurement accuracy. The entire domain including conductance guidewire, vessel, and tissue was assumed to be cylindrically axisymmetric similar to previous conductance catheter studies [3,7,8].…”

Section: Methodsmentioning

confidence: 99%

“…They obtain specimens from a USDA approved slaughterhouse. The procedure for ex-vivo measurements was consistent with our previous study [6]. Briefly, isolated segments of arteries were obtained from a slaughter house and rinsed with saline.…”

Section: Methodsmentioning

confidence: 99%

“…This assumption may be challenged when G p becomes excessively high (e.g., when over 90% of current is lost through the vessel wall and surrounding tissue). As we have recently shown, G p is strongly influenced by the distance (L EE ) between the excitation electrodes [6] so that the accuracy of lumen sizing can be deteriorated by a greater G p due to a larger excitation spacing. As the range of vessel diameter (D) of interest becomes larger, the distance between the excitation electrodes must increase to maintain the cylindricity of electric field such that L EE > 2D [3].…”

Section: Introductionmentioning

confidence: 99%

“…In fact, our previous study [6] has shown that the unfavorable impact of parallel conductance on the accuracy of conductance guidewire measurement can be decreased by the combination of 1) a smaller excitation electrodes spacing (L EE ) for a relatively smaller range of coronary RVDs and 2) superficial anatomical positions with surrounding fatty tissue of coronary arteries. Unfortunately these conditions (smaller range of dimensions and superficial epicardial coronary arteries) may not hold for the peripheral arteries.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Optimization of Peripheral Vascular Sizing with Conductance Guidewire: Theory and Experiment

et al. 2017

Self Cite

View full text Add to dashboard Cite

Although the clinical range of interventions for coronary arteries is about 2 to 5 mm, the range of diameters of peripheral vasculature is significantly larger (about 10 mm for human iliac artery). When the vessel diameter is increased, the spacing between excitation electrodes on a conductance sizing device must also increase to accommodate the greater range of vessel diameters. The increase in the excitation electrodes distance, however, causes higher parallel conductance or current losses outside of artery lumen. We have previously shown that the conductance catheter/guidewire excitation electrode distances affects the measurement accuracy for the peripheral artery lumen sizing. Here, we propose a simple solution that varies the detection electrode distances to compensate for parallel conductance losses. Computational models were constructed to simulate the conductance guidewire with various electrodes spacing combinations over a range of peripheral artery lumen diameters and surrounding tissue electrical conductivities. The results demonstrate that the measurement accuracy may be significantly improved by increased detection spacing. Specifically, an optimally configured detection/excitation spacing (i.e., 5-5-5 or an equidistant electrode interval with a detection-to-excitation spacing ratio of 0.3) was shown to accurately predict the lumen diameter (i.e., -10% < error < 10%) over a broad range of peripheral artery dimensions (4 mm < diameter < 10 mm). The computational results were substantiated with both ex-vivo and in-vivo measurements of peripheral arteries. The present results support the accuracy of the conductance technique for measurement of peripheral reference vessel diameter.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Optimization of Peripheral Vascular Sizing with Conductance Guidewire: Theory and Experiment

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

Size of cortical generators of epileptic interictal events and visibility on scalp EEG

et al. 2014

View full text Add to dashboard Cite

Growing evidence indicates that fast oscillations (>80 Hz) can be recorded interictally in the scalp EEG of patients with epilepsy, and that they may point to the seizure-onset zone. However, mechanisms underpinning the emergence of scalp fast oscillations, and whether they differ from those of interictal epileptic discharges (IEDs), are yet to be understood. The visibility of cortical electric activity on scalp EEG recordings is dependent on two factors: the characteristics of the cortical generator and the background level. We studied this issue using scalp EEG recordings and detailed simulations, with a finite element model including 8 million elements and 8 different tissues. We observed an almost linear relationship between the amplitude of scalp electric potential and the extent of the generator on the cortex. However, this relationship is subject to substantial variability, with variations in factors greater than 3 occurring simply by changing the location on the cortex of generators of fixed extent. In addition, we showed that the background power in scalp EEG recordings decreases at higher frequency bands, being inversely proportional to a power of 2.5 of the frequency. In the specific case of fast oscillations, they can be detected within the lower noise level of the ripple band (80-200 Hz) even though their median amplitude on scalp EEG recordings is more than 10 times smaller than IEDs and consistent with cortical generators of approximately 1 cm(2). In conclusion, the physics governing the propagation of electrical activity from the brain to the scalp are consistent with the hypothesis that scalp fast oscillations and intracranial high-frequency oscillations (HFOs, 80-500 Hz) are expressions of common generators. Given the potential role of HFOs as biomarkers in epilepsy, the possibility to obtain some of the associated information from scalp EEG is of high clinical significance.

show abstract

Extent of cortical generators visible on the scalp: Effect of a subdural grid

et al. 2014

View full text Add to dashboard Cite

1 Both authors contributed equally. Highlights• Subdural grids attenuate the scalp potential of generators located under them.• Attenuation of subdural grids and amplification of skull holes do not cancel each other.• Minimum cortical extents of visible scalp activity could be smaller than previously reported. AbstractThe effect of the non-conducting substrate of a subdural grid on the scalp electric potential distribution is studied through simulations. Using a detailed head model and the Finite Element Method we show that the governing physics equations predict an important attenuation in the scalp potential for generators located under the grid, and an amplification for generators located under holes in the skull filled with conductive media. These effects are spatially localized and do not cancel each other. A 4 x 8 cm grid can produce attenuations of 2 to 3 times, and an 8 x 8 cm grid attenuation of up to 8 times. As a consequence, when there is no subdural grid, generators of 4 to 8 cm 2 produce scalp potentials of the same maximum amplitude as generators of 10 to 20 cm 2 under the center of a subdural grid. This means that the minimum cortical extents necessary to produce visible scalp activity determined from simultaneous scalp and subdural recordings can be overestimations.

show abstract

Impact of surrounding tissue on conductance measurement of coronary and peripheral lumen area

Cited by 5 publications

References 38 publications

Optimization of Peripheral Vascular Sizing with Conductance Guidewire: Theory and Experiment

Optimization of Peripheral Vascular Sizing with Conductance Guidewire: Theory and Experiment

Size of cortical generators of epileptic interictal events and visibility on scalp EEG

Extent of cortical generators visible on the scalp: Effect of a subdural grid

Contact Info

Product

Resources

About