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Article ; Online: The renal vasodilatation from β-adrenergic activation in vivo in rats is not driven by K

Sorensen, Charlotte Mehlin / Salomonsson, Max / Lubberding, Anniek Frederike / Holstein-Rathlou, Niels-Henrik

2024

Abstract: The mechanisms behind renal vasodilatation elicited by stimulation of β-adrenergic receptors are not clarified. As several classes of K channels are potentially activated, we tested the hypothesis that KV7 and BKCa channels contribute to the decreased ... ...

Abstract	The mechanisms behind renal vasodilatation elicited by stimulation of β-adrenergic receptors are not clarified. As several classes of K channels are potentially activated, we tested the hypothesis that KV7 and BKCa channels contribute to the decreased renal vascular tone in vivo and in vitro. Changes in renal blood flow (RBF) during β-adrenergic stimulation were measured in anaesthetized rats using an ultrasonic flow probe. The isometric tension of segmental arteries from normo- and hypertensive rats and segmental arteries from wild-type mice and mice lacking functional K
Language	English
Publishing date	2024-03-09
Publishing country	England
Document type	Journal Article
ZDB-ID	1016295-1
ISSN	1469-445X ; 0958-0670
ISSN (online)	1469-445X
ISSN	0958-0670
DOI	10.1113/EP091618
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Article ; Online: Microvascular Imaging with Super-Resolution Ultrasound.

Andersen, Sofie Bech / Sørensen, Charlotte Mehlin / Jensen, Jørgen Arendt / Nielsen, Michael Bachmann

Ultraschall in der Medizin (Stuttgart, Germany : 1980)

2022 Volume 43, Issue 6, Page(s) 543–547

Title translation	Mikrovaskuläre Bildgebung mittels Superresolution-Ultraschall.
MeSH term(s)	Humans ; Ultrasonography/methods ; Microbubbles
Language	German
Publishing date	2022-12-05
Publishing country	Germany
Document type	Editorial
ZDB-ID	801064-x
ISSN	1438-8782 ; 1439-0914 ; 1431-4894 ; 0172-4614
ISSN (online)	1438-8782
ISSN	1439-0914 ; 1431-4894 ; 0172-4614
DOI	10.1055/a-1937-6868
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Zs.A 1572: Show issues

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Article ; Online: Myoendothelial communication in the renal vasculature and the impact of drugs used clinically to treat hypertension.

Sorensen, Charlotte Mehlin / Cupples, William A

Current opinion in pharmacology

2019 Volume 45, Page(s) 49–56

Abstract: The renal vasculature has many peculiarities including highly irregular branching. Renal blood flow must sustain adequate perfusion and maintain a high glomerular filtration. Renal autoregulation helps control renal blood flow. The local autoregulatory ... ...

Abstract	The renal vasculature has many peculiarities including highly irregular branching. Renal blood flow must sustain adequate perfusion and maintain a high glomerular filtration. Renal autoregulation helps control renal blood flow. The local autoregulatory mechanism, tubuloglomerular feedback, elicits a vasoconstriction that can be found not only in neighboring nephrons but over large areas of the kidney indicating that the renal vasculature supports strong conduction of vascular responses. The basis for conduction is intercellular communication through gap junctions. The endothelium is strongly coupled and serves as a vascular conduction highway leading the signal to the vascular smooth muscle cells through myoendothelial coupling. Extensive intercellular coupling is also found in renin secreting cells where gap junctions seem to tie the cells together to improve control of renin secretion. Lack of coupling leads to dysregulation of renin secretion and hypertension. However, the activity of the renin-angiotensin system also controls gap junction expression in the kidney. Treatment reducing angiotensin II activity, as used in hypertension treatment, can affect expression of renal and vascular gap junction.
MeSH term(s)	Animals ; Antihypertensive Agents/pharmacology ; Cell Communication/drug effects ; Connexins/physiology ; Endothelial Cells/drug effects ; Endothelial Cells/physiology ; Endothelium, Vascular/drug effects ; Endothelium, Vascular/physiology ; Gap Junctions/drug effects ; Gap Junctions/physiology ; Humans ; Kidney/drug effects ; Kidney/physiology ; Myocytes, Smooth Muscle/drug effects ; Myocytes, Smooth Muscle/physiology
Chemical Substances	Antihypertensive Agents ; Connexins
Language	English
Publishing date	2019-05-06
Publishing country	England
Document type	Journal Article ; Review
ZDB-ID	2037057-X
ISSN	1471-4973 ; 1471-4892
ISSN (online)	1471-4973
ISSN	1471-4892
DOI	10.1016/j.coph.2019.04.005
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Article ; Online: Universal Synthetic Aperture Sequence for Anatomic, Functional, and Super Resolution Imaging.

Jensen, Jorgen Arendt / Tomov, Borislav Gueorguiev / Haslund, Lars Emil / Panduro, Nathalie Sarup / Sorensen, Charlotte Mehlin

IEEE transactions on ultrasonics, ferroelectrics, and frequency control

2023 Volume 70, Issue 7, Page(s) 708–720

Abstract: Synthetic aperture (SA) can be used for both anatomic and functional imaging, where tissue motion and blood velocity are revealed. Often, sequences optimized for anatomic B-mode imaging are different from functional sequences, as the best distribution ... ...

Abstract	Synthetic aperture (SA) can be used for both anatomic and functional imaging, where tissue motion and blood velocity are revealed. Often, sequences optimized for anatomic B-mode imaging are different from functional sequences, as the best distribution and number of emissions are different. B-mode sequences demand many emissions for a high contrast, whereas flow sequences demand short sequences for high correlations yielding accurate velocity estimates. This article hypothesizes that a single, universal sequence can be developed for linear array SA imaging. This sequence yields high-quality linear and nonlinear B-mode images as well as accurate motion and flow estimates for high and low blood velocities and super-resolution images. Interleaved sequences with positive and negative pulse emissions for the same spherical virtual source were used to enable flow estimation for high velocities and make continuous long acquisitions for low-velocity estimation. An optimized pulse inversion (PI) sequence with 2 ×12 virtual sources was implemented for four different linear array probes connected to either a Verasonics Vantage 256 scanner or the SARUS experimental scanner. The virtual sources were evenly distributed over the whole aperture and permuted in emission order for making flow estimation possible using 4, 8, or 12 virtual sources. The frame rate was 208 Hz for fully independent images for a pulse repetition frequency of 5 kHz, and recursive imaging yielded 5000 images per second. Data were acquired from a phantom mimicking the carotid artery with pulsating flow and the kidney of a Sprague-Dawley rat. Examples include anatomic high contrast B-mode, non-linear B-mode, tissue motion, power Doppler, color flow mapping (CFM), vector velocity imaging, and super-resolution imaging (SRI) derived from the same dataset and demonstrate that all imaging modes can be shown retrospectively and quantitative data derived from it.
MeSH term(s)	Animals ; Rats ; Retrospective Studies ; Rats, Sprague-Dawley ; Carotid Arteries/diagnostic imaging ; Carotid Artery, Common ; Image Enhancement/methods ; Phantoms, Imaging ; Blood Flow Velocity ; Ultrasonography/methods
Language	English
Publishing date	2023-06-29
Publishing country	United States
Document type	Journal Article
ISSN	1525-8955
ISSN (online)	1525-8955
DOI	10.1109/TUFFC.2023.3280803
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Article ; Online: A hybrid approach to full-scale reconstruction of renal arterial network.

Xu, Peidi / Holstein-Rathlou, Niels-Henrik / Søgaard, Stinne Byrholdt / Gundlach, Carsten / Sørensen, Charlotte Mehlin / Erleben, Kenny / Sosnovtseva, Olga / Darkner, Sune

Scientific reports

2023 Volume 13, Issue 1, Page(s) 7569

Abstract: The renal vasculature, acting as a resource distribution network, plays an important role in both the physiology and pathophysiology of the kidney. However, no imaging techniques allow an assessment of the structure and function of the renal vasculature ... ...

Abstract	The renal vasculature, acting as a resource distribution network, plays an important role in both the physiology and pathophysiology of the kidney. However, no imaging techniques allow an assessment of the structure and function of the renal vasculature due to limited spatial and temporal resolution. To develop realistic computer simulations of renal function, and to develop new image-based diagnostic methods based on artificial intelligence, it is necessary to have a realistic full-scale model of the renal vasculature. We propose a hybrid framework to build subject-specific models of the renal vascular network by using semi-automated segmentation of large arteries and estimation of cortex area from a micro-CT scan as a starting point, and by adopting the Global Constructive Optimization algorithm for generating smaller vessels. Our results show a close agreement between the reconstructed vasculature and existing anatomical data obtained from a rat kidney with respect to morphometric and hemodynamic parameters.
MeSH term(s)	Animals ; Rats ; Artificial Intelligence ; Arteries ; Kidney/diagnostic imaging ; Kidney/physiology ; Acceptance and Commitment Therapy ; X-Ray Microtomography
Language	English
Publishing date	2023-05-09
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2615211-3
ISSN	2045-2322 ; 2045-2322
ISSN (online)	2045-2322
ISSN	2045-2322
DOI	10.1038/s41598-023-34739-y
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Book ; Online: Extremely weakly-supervised blood vessel segmentation with physiologically based synthesis and domain adaptation

Xu, Peidi / Sosnovtseva, Olga / Sørensen, Charlotte Mehlin / Erleben, Kenny / Darkner, Sune

2023

Abstract: Accurate analysis and modeling of renal functions require a precise segmentation of the renal blood vessels. Micro-CT scans provide image data at higher resolutions, making more small vessels near the renal cortex visible. Although deep-learning-based ... ...

Abstract	Accurate analysis and modeling of renal functions require a precise segmentation of the renal blood vessels. Micro-CT scans provide image data at higher resolutions, making more small vessels near the renal cortex visible. Although deep-learning-based methods have shown state-of-the-art performance in automatic blood vessel segmentations, they require a large amount of labeled training data. However, voxel-wise labeling in micro-CT scans is extremely time-consuming given the huge volume sizes. To mitigate the problem, we simulate synthetic renal vascular trees physiologically while generating corresponding scans of the simulated trees by training a generative model on unlabeled scans. This enables the generative model to learn the mapping implicitly without the need for explicit functions to emulate the image acquisition process. We further propose an additional segmentation branch over the generative model trained on the generated scans. We demonstrate that the model can directly segment blood vessels on real scans and validate our method on both 3D micro-CT scans of rat kidneys and a proof-of-concept experiment on 2D retinal images. Code and 3D results are available at https://github.com/miccai2023anony/RenalVesselSeg
Keywords	Electrical Engineering and Systems Science - Image and Video Processing ; Computer Science - Computer Vision and Pattern Recognition ; Computer Science - Machine Learning
Subject code	004
Publishing date	2023-05-26
Publishing country	us
Document type	Book ; Online
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Article: Super-Resolution Ultrasound Imaging Can Quantify Alterations in Microbubble Velocities in the Renal Vasculature of Rats.

Andersen, Sofie Bech / Taghavi, Iman / Søgaard, Stinne Byrholdt / Hoyos, Carlos Armando Villagómez / Nielsen, Michael Bachmann / Jensen, Jørgen Arendt / Sørensen, Charlotte Mehlin

Diagnostics (Basel, Switzerland)

2022 Volume 12, Issue 5

Abstract: Super-resolution ultrasound imaging, based on the localization and tracking of single intravascular microbubbles, makes it possible to map vessels below 100 µm. Microbubble velocities can be estimated as a surrogate for blood velocity, but their clinical ...

Abstract	Super-resolution ultrasound imaging, based on the localization and tracking of single intravascular microbubbles, makes it possible to map vessels below 100 µm. Microbubble velocities can be estimated as a surrogate for blood velocity, but their clinical potential is unclear. We investigated if a decrease in microbubble velocity in the arterial and venous beds of the renal cortex, outer medulla, and inner medulla was detectable after intravenous administration of the α1-adrenoceptor antagonist prazosin. The left kidneys of seven rats were scanned with super-resolution ultrasound for 10 min before, during, and after prazosin administration using a bk5000 ultrasound scanner and hockey-stick probe. The super-resolution images were manually segmented, separating cortex, outer medulla, and inner medulla. Microbubble tracks from arteries/arterioles were separated from vein/venule tracks using the arterial blood flow direction. The mean microbubble velocities from each scan were compared. This showed a significant prazosin-induced velocity decrease only in the cortical arteries/arterioles (from 1.59 ± 0.38 to 1.14 ± 0.31 to 1.18 ± 0.33 mm/s,
Language	English
Publishing date	2022-04-28
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2662336-5
ISSN	2075-4418
ISSN	2075-4418
DOI	10.3390/diagnostics12051111
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Article: Super-Resolution Ultrasound Imaging of Renal Vascular Alterations in Zucker Diabetic Fatty Rats during the Development of Diabetic Kidney Disease.

Søgaard, Stinne Byrholdt / Andersen, Sofie Bech / Taghavi, Iman / Schou, Mikkel / Christoffersen, Christina / Jacobsen, Jens Christian Brings / Kjer, Hans Martin / Gundlach, Carsten / McDermott, Amy / Jensen, Jørgen Arendt / Nielsen, Michael Bachmann / Sørensen, Charlotte Mehlin

Diagnostics (Basel, Switzerland)

2023 Volume 13, Issue 20

Abstract: Individuals with diabetes at risk of developing diabetic kidney disease (DKD) are challenging to identify using currently available clinical methods. Prognostic accuracy and initiation of treatment could be improved by a quantification of the renal ... ...

Abstract	Individuals with diabetes at risk of developing diabetic kidney disease (DKD) are challenging to identify using currently available clinical methods. Prognostic accuracy and initiation of treatment could be improved by a quantification of the renal microvascular rarefaction and the increased vascular tortuosity during the development of DKD. Super-resolution ultrasound (SRUS) imaging is an in vivo technique capable of visualizing blood vessels at sizes below 75 µm. This preclinical study aimed to investigate the alterations in renal blood vessels' density and tortuosity in a type 2 diabetes rat model, Zucker diabetic fatty (ZDF) rats, as a prediction of DKD. Lean age-matched Zucker rats were used as controls. A total of 36 rats were studied, subdivided into ages of 12, 22, and 40 weeks. Measured albuminuria indicated the early stage of DKD, and the SRUS was compared with the ex vivo micro-computed tomography (µCT) of the same kidneys. Assessed using the SRUS imaging, a significantly decreased cortical vascular density was detected in the ZDF rats from 22 weeks of age compared to the healthy controls, concomitant with a significantly increased albuminuria. Already by week 12, a trend towards a decreased cortical vascular density was found prior to the increased albuminuria. The quantified vascular density in µCT corresponded with the in vivo SRUS imaging, presenting a consistently lower vascular density in the ZDF rats. Regarding vessel tortuosity, an overall trend towards an increased tortuosity was present in the ZDF rats. SRUS shows promise for becoming an additional tool for monitoring and prognosing DKD. In the future, large-scale animal studies and human trials are needed for confirmation.
Language	English
Publishing date	2023-10-12
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2662336-5
ISSN	2075-4418
ISSN	2075-4418
DOI	10.3390/diagnostics13203197
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Book ; Online: A Hybrid Approach to Full-Scale Reconstruction of Renal Arterial Network

Xu, Peidi / Holstein-Rathlou, Niels-Henrik / Søgaard, Stinne Byrholdt / Gundlach, Carsten / Sørensen, Charlotte Mehlin / Erleben, Kenny / Sosnovtseva, Olga / Darkner, Sune

2023

Abstract	The renal vasculature, acting as a resource distribution network, plays an important role in both the physiology and pathophysiology of the kidney. However, no imaging techniques allow an assessment of the structure and function of the renal vasculature due to limited spatial and temporal resolution. To develop realistic computer simulations of renal function, and to develop new image-based diagnostic methods based on artificial intelligence, it is necessary to have a realistic full-scale model of the renal vasculature. We propose a hybrid framework to build subject-specific models of the renal vascular network by using semi-automated segmentation of large arteries and estimation of cortex area from a micro-CT scan as a starting point, and by adopting the Global Constructive Optimization algorithm for generating smaller vessels. Our results show a statistical correspondence between the reconstructed data and existing anatomical data obtained from a rat kidney with respect to morphometric and hemodynamic parameters. Comment: 19 pages, 5 figures (excluding references and supplementary) submitted to Communications Biology
Keywords	Computer Science - Computational Engineering ; Finance ; and Science ; Computer Science - Computer Vision and Pattern Recognition ; Quantitative Biology - Tissues and Organs
Subject code	006
Publishing date	2023-03-03
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: In Vivo Motion Correction in Super-Resolution Imaging of Rat Kidneys.

Taghavi, Iman / Andersen, Sofie Bech / Hoyos, Carlos Armando Villagomez / Nielsen, Michael Bachmann / Sorensen, Charlotte Mehlin / Jensen, Jorgen Arendt

IEEE transactions on ultrasonics, ferroelectrics, and frequency control

2021 Volume 68, Issue 10, Page(s) 3082–3093

Abstract: Super-resolution (SR) imaging has the potential of visualizing the microvasculature down to the 10- [Formula: see text] level, but motion induced by breathing, heartbeats, and muscle contractions are often significantly above this level. This article, ... ...

Abstract	Super-resolution (SR) imaging has the potential of visualizing the microvasculature down to the 10- [Formula: see text] level, but motion induced by breathing, heartbeats, and muscle contractions are often significantly above this level. This article, therefore, introduces a method for estimating tissue motion and compensating for this. The processing pipeline is described and validated using Field II simulations of an artificial kidney. In vivo measurements were conducted using a modified bk5000 research scanner (BK Medical, Herlev, Denmark) with a BK 9009 linear array probe employing a pulse amplitude modulation scheme. The left kidney of ten Sprague-Dawley rats was scanned during open laparotomy. A 1:10 diluted SonoVue contrast agent (Bracco, Milan, Italy) was injected through a jugular vein catheter at 100 [Formula: see text]/min. Motion was estimated using speckle tracking and decomposed into contributions from the heartbeats, breathing, and residual motion. The estimated peak motions and their precisions were: heart: axial- [Formula: see text] and lateral- [Formula: see text], breathing: axial- [Formula: see text] and lateral- [Formula: see text], and residual: axial-30 [Formula: see text] and lateral-90 [Formula: see text]. The motion corrected microbubble tracks yielded SR images of both bubble density and blood vector velocity. The estimation was, thus, sufficiently precise to correct shifts down to the 10- [Formula: see text] capillary level. Similar results were found in the other kidney measurements with a restoration of resolution for the small vessels demonstrating that motion correction in 2-D can enhance SR imaging quality.
MeSH term(s)	Animals ; Contrast Media ; Diagnostic Imaging ; Kidney/diagnostic imaging ; Motion ; Rats ; Rats, Sprague-Dawley
Chemical Substances	Contrast Media
Language	English
Publishing date	2021-09-27
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	1525-8955
ISSN (online)	1525-8955
DOI	10.1109/TUFFC.2021.3086983
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