Diameter measurement from images of fluorescent cylinders embedded in tissue

Rolf, Marijn P.; Wee, Rene ter; Leeuwen, Ton G. van; Spaan, Jos A. E.; Streekstra, Geert J.

doi:10.1007/s11517-008-0328-9

Cited by 22 publications

(27 citation statements)

References 13 publications

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“…Recently, the point spread function has become available for the embedding medium in combination with the imaging system (22). Based on that study, the error made for the diameter values reported here was estimated.…”

Section: Discussionmentioning

confidence: 97%

Porcine coronary collateral formation in the absence of a pressure gradient remote of the ischemic border zone

Wijngaard

Schulten

Horssen

et al. 2011

American Journal of Physiology-Heart and Circulatory Physiology

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van den Wijngaard JP, Schulten H, van Horssen P, ter Wee RD, Siebes M, Post MJ, Spaan JA. Porcine coronary collateral formation in the absence of a pressure gradient remote of the ischemic border zone. Am J Physiol Heart Circ Physiol 300: H1930 -H1937, 2011. First published March 11, 2011 doi:10.1152/ajpheart.00403.2010.-In the current paradigm on coronary collateral development, it is assumed that these vessels develop consequentially from increased fluid shear stress (FSS) through preexisting collateral arteries. The increased FSS follows from an increase in pressure gradient between the region at risk and well-perfused surroundings. The objective of this study was to test the hypothesis that, in the heart, collateral connections can form in the absence of an increased FFS and consequentially at any depth and region within the ventricular wall. In Yorkshire pigs, gradual left circumflex coronary artery occlusion was obtained over 6 wk by an ameroid constrictor, whereas the control group underwent a sham operation. Hearts were harvested and subsequently processed in an imaging cryomicrotome, resulting in 40-m voxel resolution threedimensional reconstructions of the intramural vascular vessels. Dedicated software segmented the intramural vessels and all continuous vascular pathways containing a collateral connection. In the ameroid group, 192 collaterals, 22-1,049 m in diameter, were detected with 62% within the subendocardium. Sixty percent of collaterals bridged from the left anterior descending artery to left circumflex coronary artery. A novel result is that 25% (n ϭ 48) of smaller-radius collaterals (P ϭ 0.047) connected with both origin and terminus in the nontarget area where perfusion was assumed uncompromised. In the porcine heart, collateral vessels develop not only in ischemic border zones with increased FSS but also away from such border zones where increased FSS is unlikely. The majority of collaterals were located at the subendocardium, corresponding to the region with highest prevalence for ischemia. imaging cryomicrotome; collaterals; ischemia; remodeling; fluid shear stress STIMULATING CORONARY COLLATERAL formation by neovascularization may serve as a last therapeutic resort for patients that cannot be successfully revascularized by coronary artery bypass surgery or percutaneous coronary intervention. However, further development of this therapeutic modality requires more detailed information on the mechanisms of collateral formation.There are differences of opinion whether in the porcine heart collaterals grow de novo, i.e., through angiogenesis stimulated by ischemia, or from innate nonfunctional collaterals that are already present, i.e., arteriogenesis stimulated by shear stress (23,29). In the hindlimb occlusion model, collaterals growing in the nonischemic area proximal to the experimentally induced flow obstruction clearly indicates the role of increased fluid shear stress (FSS) in outward remodeling (7, 9, 23). In the heart, however, regions of ischemia are intertwined with areas of inc...

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Section: Discussionmentioning

confidence: 97%

Porcine coronary collateral formation in the absence of a pressure gradient remote of the ischemic border zone

Wijngaard

Schulten

Horssen

et al. 2011

American Journal of Physiology-Heart and Circulatory Physiology

Self Cite

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“…Fluorescence images are degraded due to scattering of emission light in the tissue, lens blurring, and light emanating from structures beneath the imaged surface. For the arterial cast images, image restoration entailed deconvolution with a systemspecific point spread function (12). Correction of the image stack was performed in the spatial domain using a 3D iterative deconvolution program written in CUDA (NVidia) (3).…”

Section: Methodsmentioning

confidence: 99%

Influence of segmented vessel size due to limited imaging resolution on coronary hyperemic flow prediction from arterial crown volume

Horssen

Lier

Wijngaard

et al. 2016

American Journal of Physiology-Heart and Circulatory Physiology

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van Horssen P, van Lier MG, van den Wijngaard JP, VanBavel E, Hoefer IE, Spaan JA, Siebes M. Influence of segmented vessel size due to limited imaging resolution on coronary hyperemic flow prediction from arterial crown volume. Am J Physiol Heart Circ Physiol 310: H839 -H846, 2016. First published January 29, 2016 doi:10.1152/ajpheart.00728.2015.-Computational predictions of the functional stenosis severity from coronary imaging data use an allometric scaling law to derive hyperemic blood flow (Q) from coronary arterial volume (V), Q ϭ ␣V ␤ . Reliable estimates of ␣ and ␤ are essential for meaningful flow estimations. We hypothesize that the relation between Q and V depends on imaging resolution. In five canine hearts, fluorescent microspheres were injected into the left anterior descending coronary artery during maximal hyperemia. The coronary arteries of the excised heart were filled with fluorescent cast material, frozen, and processed with an imaging cryomicrotome to yield a three-dimensional representation of the coronary arterial network. The effect of limited image resolution was simulated by assessing scaling law parameters from the virtual arterial network at 11 truncation levels ranging from 50 to 1,000 m segment radius. Mapped microsphere locations were used to derive the corresponding relative Q using a reference truncation level of 200 m. The scaling law factor ␣ did not change with truncation level, despite considerable intersubject variability. In contrast, the scaling law exponent ␤ decreased from 0.79 to 0.55 with increasing truncation radius and was significantly lower for truncation radii above 500 m vs. 50 m (P Ͻ 0.05). Hyperemic Q was underestimated for vessel truncation above the reference level. In conclusion, flow-crown volume relations confirmed overall power law behavior; however, this relation depends on the terminal vessel radius that can be visualized. The scaling law exponent ␤ should therefore be adapted to the resolution of the imaging modality. FRACTIONAL FLOW RESERVE (FFR) has been shown to be a reliable and a widely accepted method to assess whether a coronary artery stenosis is responsible for myocardial ischemia (11). Conceptually, FFR is defined as the hyperemic flow in a vessel with a stenosis relative to the hypothetical hyperemic flow in the undiseased vessel. In practice, FFR is measured invasively as the ratio between pressure distal to a stenosis and aortic pressure, during adenosine-induced hyperemia. This requires passing of a guide wire with a pressure sensor through the stenosis. Despite the reliability of this method, risks of vessel and plaque rupture, procedure time, and costs have inspired the search for new less-invasive alternatives for assessing FFR (18), based on computational methods applied to arterial models obtained from angiography (27) or CT (6). By using experimentally established form-function relationships, coronary flow can be calculated from image-derived morphological data. These relationships are expressed in terms of allometric scaling laws r...

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“…The prevalent way to describe the recording process is via pointspread functions (PSF) [7], which are mathematical models of how optical media blurs an imaged object. In essence, a PSF describes the response of an optically active system to a point light source, so its precise definition is that of a Green's (or impulse response) function.…”

Section: Tissue Opticsmentioning

confidence: 99%

Parallel Simulation for Parameter Estimation of Optical Tissue Properties

Duta¹,

Thiyagalingam²,

Trefethen³

et al. 2010

Euro-Par 2010 - Parallel Processing

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Abstract. Several important laser-based medical treatments rest on the crucial knowledge of the response of tissues to laser penetration. Optical properties are often localised and are measured using optically active fluorescent microspheres injected into the tissue. However, the measurement process combines the tissue properties with the optical characteristics of the measuring device which in turn requires numerically intensive mathematical simulations for extracting the tissue properties from the data.In this paper, we focus on exploiting the algorithmic parallelism in the biocomputational simulation, in order to achieve significant runtime reductions. The entire simulation accounts for over 30,000 spatial points and is too computationally demanding to run in a serial fashion. We discuss our strategies of parallelisation at different levels of granularity and we present our results on two different parallel platforms. We also emphasise the importance of retaining a high level of code abstraction in the application to benefit both agile coding and interdisciplinary collaboration between research groups.

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Diameter measurement from images of fluorescent cylinders embedded in tissue

Cited by 22 publications

References 13 publications

Porcine coronary collateral formation in the absence of a pressure gradient remote of the ischemic border zone

Porcine coronary collateral formation in the absence of a pressure gradient remote of the ischemic border zone

Influence of segmented vessel size due to limited imaging resolution on coronary hyperemic flow prediction from arterial crown volume

Parallel Simulation for Parameter Estimation of Optical Tissue Properties

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