scholarly journals Doppler ultrasound cardiac gating of intracranial flow at 7T

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Karin Markenroth Bloch ◽  
Fabian Kording ◽  
Johannes Töger
Keyword(s):  
Blood Flow ◽  
Doppler Ultrasound ◽  
False Positive ◽  
High Field ◽  
Phase Contrast ◽  
4D Flow ◽  
Ultra High Field ◽  
2D Flow ◽  
Cardiac Synchronization ◽  
Quantitative Flow

Abstract Background Ultra-high field magnetic resonance imaging (MR) may be used to improve intracranial blood flow measurements. However, standard cardiac synchronization methods tend to fail at ultra-high field MR. Therefore, this study aims to investigate an alternative synchronization technique using Doppler ultrasound. Methods Healthy subjects (n = 9) were examined with 7T MR. Flow was measured in the M1-branch of the middle cerebral artery (MCA) and in the cerebral aqueduct (CA) using through-plane phase contrast (2D flow). Flow in the circle of Willis was measured with three-dimensional, three-directional phase contrast (4D flow). Scans were gated with Doppler ultrasound (DUS) and electrocardiogram (ECG), and pulse oximetry data (POX) was collected simultaneously. False negative and false positive trigger events were counted for ECG, DUS and POX, and quantitative flow measures were compared. Results There were fewer false positive triggers for DUS compared to ECG (5.3 ± 11 vs. 25 ± 31, p = 0.031), while no other measured parameters differed significantly. Net blood flow in M1 was similar between DUS and ECG for 2D flow (1.5 ± 0.39 vs. 1.6 ± 0.41, bias ± 1.96SD: − 0.021 ± 0.36) and 4D flow (1.8 ± 0.48 vs. 9 ± 0.59, bias ± 1.96SD: − 0.086 ± 0.57 ml). Net CSF flow per heart beat in the CA was also similar for DUS and ECG (3.6 ± 2.1 vs. 3.0 ± 5.8, bias ± 1.96SD: 0.61 ± 13.6 μl). Conclusion Gating with DUS produced fewer false trigger events than using ECG, with similar quantitative flow values. DUS gating is a promising technique for cardiac synchronization at 7T.

16 False-positive rate after anticipation of early pregnancy diagnosis for resynchronization of ovulation in Bos indicus heifers

2019 ◽  
Vol 31 (1) ◽  
pp. 134
Author(s):  
L. M. S. Simões ◽  
E. A. Lima ◽  
A. P. C. Santos ◽  
R. E. Orlandi ◽  
M. P. Bottino ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pregnancy Rate ◽  
Doppler Ultrasound ◽  
False Positive ◽  
Doppler Ultrasonography ◽  
Bos Indicus ◽  
False Positives ◽  
Colour Doppler ◽  
Pregnancy Diagnosis ◽  
Colour Doppler Ultrasonography

The objective was to determine the incidence of false-positive pregnancy diagnosis following the use of colour Doppler ultrasonography 20 and 22 days after fixed-time AI (FTAI) in Bos indicus heifers submitted to resynchronization 14 days after first FTAI. In the study, 512 Nellore heifers at 24.5±0.8 months of age and body condition score of 3.4±0.1 were used beginning 14 days after FTAI. On Day 14, heifers received 50mg of short-acting progesterone (Afisterone®, CEVA, São Paulo, Brazil) and a progesterone device (Prociclar®, CEVA). Eight days later (Day 22), the progesterone device was removed. A duplex B-mode (grayscale) and pulse-wave colour Doppler ultrasound instrument (M5, Mindray, Shenzhen, China) equipped with a multifrequency linear transducer was used for the examination of luteal blood flow on Days 20 and 22. The percentage of luteal area with colour Doppler signals of blood flow at each examination was determined as previously described (Ginther 2007) and was classified as low [corpus luteum (CL) with less than 25% vascularized area], intermediate (CL with 25-75% vascularized area), or high (CL with more than 75% vascularized area). Heifers with intermediate and high luteal blood flow were diagnosed as pregnant by Doppler ultrasonography, and heifers with low luteal blood flow were diagnosed as nonpregnant. Heifers diagnosed as pregnant by Doppler ultrasonography were examined 30 days after FTAI by B-mode ultrasound examination for pregnancy diagnosis and to determine the number of false positives (heifers pregnant by Doppler ultrasonography and nonpregnant by B-mode ultrasonography). Statistical analysis was performed by the GLIMMIX procedure of SAS (SAS Institute Inc., Cary, NC, USA). Pregnancy rate by Doppler ultrasonography [Day 20=60.5% (310/512), Day 22=55.3% (283/512); P=0.10] and false-positive percentage [Day 20=29.7% (92/310), Day 22=23.0% (65/2830); P=0.06] were similar on pregnancy diagnoses by Doppler ultrasonography performed 20 and 22 days after FTAI. Furthermore, in the period from 20 to 22 days after FTAI, luteolysis was verified in 5.8% (30/512) of heifers. In conclusion, anticipation of pregnancy diagnosis in 2 days by evaluation of luteal blood flow with colour Doppler ultrasonography (20 days after FTAI) does not interfere with pregnancy rate by Doppler ultrasound and percentage of false positives in Bos indicus heifers.

scholarly journals 4D Flow Vorticity Visualization Predicts Regions of Quantitative Flow Inconsistency for Optimal Blood Flow Measurement

2020 ◽  
Vol 2 (1) ◽  
pp. e190054 ◽  
Author(s):  
Francisco J. Contijoch ◽  
Michael Horowitz ◽  
Evan Masutani ◽  
Seth Kligerman ◽  
Albert Hsiao
Keyword(s):  
Blood Flow ◽  
Flow Measurement ◽  
Blood Flow Measurement ◽  
4D Flow ◽  
Flow Vorticity ◽  
Quantitative Flow

Assessment of left ventricular diastolic flow in hypertrophic cardiomyopathy by 4D FLOW MRI

2019 ◽  
pp. 42-49
Author(s):  
E. Yu. Glazkova ◽  
O. Yu. Dariy ◽  
S. A. Aleksandrova ◽  
V. N. Makarenko ◽  
M. I. Berseneva ◽  
...  
Keyword(s):  
Blood Flow ◽  
Hypertrophic Cardiomyopathy ◽  
Phase Contrast ◽  
Peak Velocity ◽  
Left Ventricular ◽  
Vortical Flow ◽  
4D Flow ◽  
Phase Contrast Mri ◽  
Flow Phase ◽  
Flow Mri

Objective. To assess phase-contrast MRI in the evaluation of left ventricular hemodynamics changes in various forms of hypertrophic cardiomyopathy.Materials and methods. 11 patients were examined: without pathology of the cardiovascular system (n = 3), with apical (n = 3), diffuse-septal (n = 2) and focal-basal (n = 3) types of hypertrophic cardiomyopathy. All patients underwent MRI of the heart with an additional phase-contrast sequence of the left ventricular area. Postprocessing carried out in the 4D FLOW application (Siemens).Results. Data were obtained on the geometry and dynamics of vortex diastolic flows in the left ventricular of all patients. In patients with hypertrophic cardiomyopathy, an increase in the distance to the center of the vortex and a decrease in the normalized area and peak velocity of the vortex is determined. The diffuse-septal type is characterized by a minimal vortex peak velocity; apical type - by the maximum vortex sphericity index. For patients with a focalbasal type of hypertrophic cardiomyopathy the maximum changes in blood flow are determined in late diastole (absence of vortexes).Conclusion. 4D FLOW Phase-contrast MRI allows identifying and assessing LV vortical flow. Quantitative analysis can be used to characterize the remodeling of LV blood flow of various types of hypertrophic cardiomyopathy.

scholarly journals HELICAL BLOOD FLOW IN PULMONARY ARTERY VISUALIZED WITH PHASE-RESOLVED 3D CINE PHASE CONTRAST MRI (4D-FLOW)

2013 ◽  
Vol 61 (10) ◽  
pp. E950
Author(s):  
Kenichiro Suwa ◽  
Takeji Saito ◽  
Makoto Sano ◽  
Mamoru Nobuhara ◽  
Masao Saotome ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pulmonary Artery ◽  
Phase Contrast ◽  
4D Flow ◽  
Phase Contrast Mri ◽  
Cine Phase Contrast

scholarly journals Single-vessel cerebral blood flow fMRI to map blood velocity by phase-contrast imaging

2020 ◽  
Author(s):  
Xuming Chen ◽  
Yuanyuan Jiang ◽  
Sangcheon Choi ◽  
Rolf Pohmann ◽  
Klaus Scheffler ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
High Resolution ◽  
High Field ◽  
Phase Contrast ◽  
Blood Oxygenation ◽  
Contrast Imaging ◽  
Velocity Mapping ◽  
Single Vessel ◽  
Mapping Scheme

AbstractCurrent approaches to high-field fMRI provide two means to map hemodynamics at the level of single vessels in the brain. One is through changes in deoxyhemoglobin in venules, i.e., blood oxygenation level-dependent (BOLD) fMRI, while the second is through changes in arteriole diameter, i.e., cerebral blood volume (CBV) fMRI. Here we introduce cerebral blood flow (CBF)-fMRI, which uses high-resolution phase-contrast MRI to form velocity measurements of flow and demonstrate CBF-fMRI in single penetrating microvessels across rat parietal cortex. In contrast to the venule-dominated BOLD and arteriole-dominated CBV fMRI signal, the phase-contrast -based CBF signal changes are highly comparable from both arterioles and venules. Thus, we have developed a single-vessel fMRI platform to map the BOLD, CBV, and CBF from penetrating microvessels throughout the cortex. This high-resolution single-vessel fMRI mapping scheme not only enables the vessel-specific hemodynamic mapping in diseased animal models but also presents a translational potential to map vascular dementia in diseased or injured human brains with ultra-high field fMRI.SummaryWe established a high-resolution PC-based single-vessel velocity mapping method using the high field MRI. This PC-based micro-vessel velocity measurement enables the development of the single-vessel CBF-fMRI method. In particular, in contrast to the arteriole-dominated CBV and venule-dominated BOLD responses, the CBF-fMRI shows similar velocity changes in penetrating arterioles and venules in activated brain regions. Thus, we have built a noninvasive single-vessel fMRI mapping scheme for BOLD, CBV, and CBF hemodynamic parameter measurements in animals.

279 ReBreed21, a Rapid Reinsemination Program: Fertility in Bos Indicus Cattle of Different Parities

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 145-146
Author(s):  
João Paulo N Andrade ◽  
Pedro L Monteiro ◽  
Alexandre B Prata ◽  
Adelino Robl ◽  
José Leite ◽  
...  
Keyword(s):  
Blood Flow ◽  
Breeding Season ◽  
Doppler Ultrasound ◽  
Chorionic Gonadotropin ◽  
False Positive ◽  
Bos Indicus ◽  
Reproductive Efficiency ◽  
High Fertility ◽  
Pregnancy Diagnosis ◽  
Equine Chorionic Gonadotropin

Abstract This study evaluated efficiency of a reinsemination program allowing timed AI (TAI) every 21 days (ReBreed21; RB21) vs. a traditional Resynch program in Nellore females (n = 2,085) of different parities. First TAI followed estradiol (E2)/progesterone (P4)-based synchronization, and was considered d0. For RB21 (n= 1,357), cows received P4 insert on D12. On D19, P4 was removed, followed by treatment with equine chorionic gonadotropin (eCG) and 0.6 mg E2 Cypionate (RB21+EC, n = 60) or nothing (RB21, n=687). On D21, Doppler ultrasound was used to determine CL blood flow [< 25%=nonpregnant (NP)] and NP cows received TAI immediately together with 25µg licerelin acetate (GnRH). A second RB21 program using the same groups was done in cows that received TAI on D21 to allow a third potential TAI on D42. Pregnancy diagnosis was performed on D33 after each TAI. Cows designated pregnant on D21 but NP on D33, were termed False-Positive (FP). On D33, all control (n = 728) designated NP and FP cows were resynchronized with P4+E2 protocol for the second TAI at D42. Data were analyzed with SAS and shown in Table 1. For all cows, there were no differences in the three groups (Control, RB21, RB21+EC) for pregnancy/AI (P/AI). In nulliparous heifers, cumulative pregnancies were greater for both RB21 groups compared to Controls at D21 or D42 of the breeding season. Primiparous cows had greater cumulative pregnancies at D21 but not D42. Primiparous cows at second TAI had lower P/AI in RB21 (34.2%) vs. Control (51.7%); however, RB21-EC (55.8%) was similar to Control. No other parities had differences between RB21 and RB21+EC. Multiparous cows had high fertility at first TAI [69.3% (418/603)] and no differences between groups in cumulative pregnancies (P = 0.23). Thus, ReBreed21 program increases the reproductive efficiency in Nulliparous and Primiparous but not Multiparous Bos Indicus cattle. Adding EC to RB21 program only improves P/AI in Primiparous cows.

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