In vivo vascular modelling of abdominal aorta based on 3D speckle tracking analysis*

2012 ◽  
Vol 184 (02) ◽  
Author(s):  
S Vogt ◽  
K Karatolios ◽  
A Wittek ◽  
T Nwe ◽  
W Gorissen ◽  
...  
Keyword(s):  
Abdominal Aorta ◽  
Speckle Tracking

SECRETION OF PROGESTERONE DURING GESTATION IN THE RAT

1978 ◽  
Vol 79 (2) ◽  
pp. 179-190 ◽  
Author(s):  
MRINAL K. SANYAL
Keyword(s):  
Abdominal Aorta ◽  
Primary Source ◽  
Solvent System ◽  
Peripheral Circulation ◽  
Systemic Circulation ◽  
Maternal Circulation ◽  
Secondary Importance ◽  
System Hexane ◽  
Venous Plasma

The concentrations of progesterone and 5α-pregnane-3,20-dione in ovarian and uterine venous plasma and in the systemic circulation were measured during gestation in the rat. The steroids were quantified by radioimmunoassay after separation on silicic acid microcolumns with the solvent system hexane: ethyl acetate (5: 2, v/v). The concentration of progesterone in the systemic circulation was highest on days 3–4 and 13–17 of pregnancy; throughout gestation, the concentration of 5α-pregnane-3,20-dione was low in relation to that of progesterone and showed no marked changes as gestation proceeded. The level of progesterone in ovarian venous effluent was 10–20 times higher than that in the uterine vein and 20–50 times greater than that in the systemic circulation. The rate of secretion of progesterone by the ovary was highest during days 13–17 of gestation and ovariectomy during this period markedly reduced the levels of progesterone in the peripheral circulation. The concentration of progesterone in the uterine venous effluent was raised compared with the concentration in plasma from the abdominal aorta, especially on days 7 and 9 of pregnancy. These results suggest that, in vivo, the rat placenta synthesizes small amounts of progesterone and secretes it into the maternal circulation. The ovary is the primary source of progesterone during pregnancy and the placental contribution is of secondary importance. Although 4-ene-5α-reductase enzyme(s) is present in the ovary and placenta, significant quantities of the reduced progestin 5α-pregnane-3,20-dione are not secreted into the systemic circulation during gestation in the rat.

scholarly journals In Vivo Quantification of Regional Circumferential Green Strain in the Thoracic and Abdominal Aorta by Two-Dimensional Spiral Cine DENSE MRI

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
John S. Wilson ◽  
Xiaodong Zhong ◽  
Jackson Hair ◽  
W. Robert Taylor ◽  
John N. Oshinski
Keyword(s):  
Abdominal Aorta ◽  
Aortic Wall ◽  
Patient Specific ◽  
Peak Strain ◽  
Ssfp Cine ◽  
Green Strain ◽  
The Mean ◽  
Thoracic And Abdominal ◽  
Cine Dense

Regional tissue mechanics play a fundamental role in the patient-specific function and remodeling of the cardiovascular system. Nevertheless, regional in vivo assessments of aortic kinematics remain lacking due to the challenge of imaging the thin aortic wall. Herein, we present a novel application of displacement encoding with stimulated echoes (DENSE) magnetic resonance imaging (MRI) to quantify the regional displacement and circumferential Green strain of the thoracic and abdominal aorta. Two-dimensional (2D) spiral cine DENSE and steady-state free procession (SSFP) cine images were acquired at 3T at either the infrarenal abdominal aorta (IAA), descending thoracic aorta (DTA), or distal aortic arch (DAA) in a pilot study of six healthy volunteers (22–59 y.o., 4 females). DENSE data were processed with multiple custom noise reduction techniques including time-smoothing, displacement vector smoothing, sectorized spatial smoothing, and reference point averaging to calculate circumferential Green strain across 16 equispaced sectors around the aorta. Each volunteer was scanned twice to evaluate interstudy repeatability. Circumferential Green strain was heterogeneously distributed in all volunteers and locations. The mean spatial heterogeneity index (standard deviation of all sector values divided by the mean strain) was 0.37 in the IAA, 0.28 in the DTA, and 0.59 in the DAA. Mean (homogenized) peak strain by DENSE for each cross section was consistent with the homogenized linearized strain estimated from SSFP cine. The mean difference in peak strain across all sectors following repeat imaging was −0.1±2.3%, with a mean absolute difference of 1.7%. Aortic cine DENSE MRI is a viable noninvasive technique for quantifying heterogeneous regional aortic wall strain and has significant potential to improve patient-specific clinical assessments of numerous aortopathies, as well as to provide the lacking spatiotemporal data required to refine patient-specific computational models of aortic growth and remodeling.

Hemodynamics in the abdominal aorta: a comparison of in vitro and in vivo measurements

1994 ◽  
Vol 76 (4) ◽  
pp. 1520-1527 ◽  
Author(s):  
J. E. Moore ◽  
S. E. Maier ◽  
D. N. Ku ◽  
P. Boesiger
Keyword(s):  
Abdominal Aorta ◽  
Velocity Profiles ◽  
Flow Reversal ◽  
Infrarenal Aorta ◽  
Complex Flow ◽  
Flow Measurements ◽  
In Vivo Measurements ◽  
Made In

In vivo measurements of blood velocity profiles are difficult to obtain and interpret, since the parameters that govern the normally highly complex flow situation may not be fully quantified or understood at the time of measurement. In vitro flow models have been used often to better understand vascular hemodynamics. The assumptions made in the design of these models limit the applicability of the results. In this study, in vitro flow measurements made in a carefully designed model of the abdominal aorta were compared with in vivo measurements obtained with magnetic resonance imaging. In the suprarenal aorta, the velocity profiles were mostly forward and axisymmetric in both the in vitro and in vivo cases. In the infrarenal aorta, there was extensive flow reversal noted near the posterior wall in both cases. In the aortic bifurcation, two peaks of flow reversal were noted near the lateral posterior walls, and M-shaped velocity profiles were observed in late diastole. The in vitro and in vivo measurements exhibited good qualitative agreement. The in vitro model was accurate in modeling the in vivo hemodynamics of the abdominal aorta. The complex phenomena observed in vivo were explained on the basis of knowledge gained from the in vitro study.

Abstract 460: 64 Cu-DOTATATE for in vivo Positron Emission Tomography Imaging of Somatostatin Receptor 2 Expressing Macrophages in a Göttingen Minipig Model of Atherosclerosis

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Sune Folke Pedersen ◽  
Trine Pagh Ludvigsen ◽  
Andreas Vegge ◽  
Camilla Schumacher-Petersen ◽  
Rasmus Sejersten Ripa ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Abdominal Aorta ◽  
Right Atrium ◽  
Plasma Lipids ◽  
Somatostatin Receptor ◽  
Emission Tomography ◽  
Activated Macrophages ◽  
Lean Control ◽  
Positron Emission

Background: Somatostatin receptor subtype 2 (SSTR 2 ) is expressed by activated macrophages which are important effector cells in atherogenesis and a major constituent of atherosclerotic plaques. SSTR 2 can be targeted non-invasively in vivo using the tracer 64 Cu-DOTATATE and positron emission tomography (PET). Methods: Male castrated Göttingen minipigs were treated according to two diet regimes for 43 weeks: chow (lean control; n=1) or high-fat/high-cholesterol diet (HFHC, obese group; n=2). Plasma lipids: total cholesterol (TC) and triglycerides (TG) were measured and SSTR 2 expression was assessed using hybrid positron emission tomography/magnetic resonance (PET/MR) imaging of the abdominal aorta, one hour (range: 60-63 minutes) post injection with 200 MBq (range 202-214 MBq) of 64 Cu-DOTATATE. Consectutive regions of interest (ROIs) were drawn guided by MR to include vessel wall and lumen of the abdominal aorta to calculate standardized uptake values (SUVs). Target-to-background (TBR) ratios were calculated using right atrium SUVs for blood pool correction (SUV vessel /SUV right atrium = TBR) and reported as mean and maximal values (TBR mean ; TBR max ). Results: Three minipigs (age 17 months) were included and PET/MR was completed in all animals. Mean uptake of 64 Cu-DOTATATE was lowest for the abdominal aorta in the lean control: TBR mean = 0.44 and TBR max = 0.73 (range: TBR mean = 0.29 - 0.62; TBR max = 0.49 - 1.10) and highest in the HFHC group: TBR mean = 0.66 and TBR max = 1.28 (range: TBR mean = 0.26 - 1.38; TBR max = 0.39 - 3.19). Plasma lipids: lean control: TC = 1.34 mmol/L; TG = 0.38 mmol/L; HFHC group (mean values): TC = 18.7mmol/L (range: 11.6 - 25.8mmol/L); TG = 0.6 mmol/L (range: 0.37 - 0.83mmol/L). Conclusion: Non-invasive 64 Cu-DOTATATE PET/MR is feasible for assessment of SSTR 2 expression in a Göttingen minipig model of diet-induced atherosclerosis. Additional studies are needed including assessment of histology findings and gene expression to confirm the presence of activated macrophages in order to validate the use of 64 Cu-DOTATATE PET/MR in this model.

scholarly journals Evaluation of Extension of Blood Vessels during Static Stretching Using Ultrasound 2D Speckle Tracking Imaging

2017 ◽  
Vol 9 (8) ◽  
pp. 1
Author(s):  
Hiromi Shinno ◽  
Satoshi Kurose ◽  
Yutaka Yamanaka ◽  
Yaeko Fukushima ◽  
Hiromi Tsutsumi ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Speckle Tracking ◽  
Vascular Endothelial Cells ◽  
Ulnar Artery ◽  
General Purpose ◽  
Speckle Tracking Imaging ◽  
Static Stretching ◽  
Maximum Angle ◽  
2D Speckle Tracking

BACKGROUND: During static stretching, a muscle extends longitudinally, and blood vessels seem to extend simultaneously. However, it is difficult to visualize, and few findings have seen. The recent progress with ultrasonography enables measurements of movement in vivo using 2D speckle tracking imaging, as well as detailed evaluation of extension in tissues at the same site. The aim of this study is to evaluate longitudinal extension of blood vessels during static stretching using this methodology.METHODS: Participants were 10 healthy female volunteers (age of 39.4±11.6). They extended their right wrist with elbow extended. Then the ulnar artery was measured by using 2D speckle tracking imaging with a general-purpose ultrasound instrument. Tissue extension per unit time at the stretching site was calculated from before stretching to maximum of stretching. Simultaneous changes in the caliber of blood vessels during stretching were measured using ultrasound M-mode.RESULTS: The maximum angle of wrist extension was 0 to 83.6±12.5°. The muscle extended by 3.80±1.65% per unit time during stretching, and blood vessels simultaneously extended by 3.20±1.96%. These changes were significant compared to measurements before stretching (p<0.01) and shows the correlation between muscles and blood vessels (r=0.56, p=0.1). The calibers of blood vessels per unit time before and during stretching were 2.24±0.27 and 1.64±0.53 mm with a significant decrease during stretching (p<0.01).CONCLUSIONS: Imaging of static stretching showed extension of both the muscle/skeletal system and blood vessels longitudinally. The finding suggests that endothelial function might be activated by mechanical stress on vascular endothelial cells.

Direct calibration of a totally implantable pulsed Doppler ultrasonic blood flowmeter

1977 ◽  
Vol 232 (5) ◽  
pp. H537-H544
Author(s):  
H. V. Allen ◽  
M. F. Anderson ◽  
J. D. Meindl
Keyword(s):  
Linear Regression ◽  
Abdominal Aorta ◽  
Regression Line ◽  
Volume Flow ◽  
Flow Profile ◽  
Pulsed Doppler ◽  
Velocity Flow ◽  
The Mean ◽  
Best Fit

A totally implantable pulsed Doppler ultrasonic blood flowmeter has recently been developed to provide information on the velocity-flow profile in a vessel as well as its diameter. Volume flow can be indirectly obtained according to the formula: Q = (phi/4)(diam)2-v. In order to determine the accuracy of this estimate, in vivo direct bleedout measurements were performed on the abdominal aorta of six dogs with an overall accuracy in 77 trials of +2.0 +/- 8.7% (mean +/- 1 SD). The best-fit mean linear regression line was found to be: flowmeter output = 1.013-true flow + 5.1 ml/min. The scatter in the flowmeter's accuracy is thought to be due to small variations in the angle of the transducer. The source of the 2% overestimation in the mean accuracy could not be directly attributed to any one condition; the error is sufficiently small that in many cases it can be neglected.

Platelet And Smooth Muscle Cell Responses After Endothelial Desquamation

1981 ◽  
Author(s):  
M B Stemerman
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Abdominal Aorta ◽  
Vessel Wall ◽  
Balloon Catheter ◽  
Muscle Cells ◽  
Mechanical Removal ◽  
Cell Counts ◽  
Old Rats

Although compromise of endothelial integrity occurs through many mechanisms, mechanical removal by balloon catheter is an excellent experimental method to study vascular responsiveness after injury. The interaction of platelets with the vessel wall, as well as proliferation of vascular smooth muscle cells can be assessed in this model. Following platelet attachment to the subendothelium, platelets release materials from their alpha granules. Using an antibody raised against platelet factor 4, a protein stored in alpha granules, we have demonstrated that material released from platelets do enter the vessel wall. A large amount of PF 4 antigen enters the wall shortly after endothelial removal, permeating the wall completely by 30 minutes, but little trace of the antigen can be found four hours after injury. Using infusions of PGI2 to a level of 850 ng/kg/min in rabbits, in vivo platelet adhesion to the exposed subendothelium can be greatly reduced and release of PF4 antigen into the vessel wall markedly diminished. Growth of smooth muscle cells (SMC) after endothelial removal has also been measured by 3H-Thymidine labeling of SMC DNA. As measured by this method as well as direct cell counts, SMC proliferation in the abdominal aorta is significantly greater than the thoracic. Reinjury of only the abdominal aorta by balloon catheter 4 days after the initial total aortic injury causes a proliferative spurt in the thoracic aortic SMC, thus demonstrating that a humoral signal can initiate SMC proliferation. In addition, the response of SMC from 21 month old rats when compared with 3 month old rats is much greater. These studies demonstrate in vivo methods for examining the response of platelets and SMC following endothelial injury. Further, these studies indicate that the response to injury hypothesis of atherosclerosis progression should now be broadened to the concept of a response to signal view of atherogenesis.

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