Angle Of Insonation Research Articles

Measurement of transcranial Doppler insonation angles from three-dimensional reconstructions of CT angiography scans.

Blood velocities measured by Transcranial Doppler (TCD) are dependent on the angle between the incident ultrasound beam and the direction of blood flow (known as the Doppler angle). However, when TCD examinations are performed without imaging the Doppler angle for each vessel segment is not known. We have measured Doppler angles in the basal cerebral arteries examined with TCD using three-dimensional (3D) vessel models generated from computed tomography angiography (CTA) scans. This approach produces angle statistics that are not accessible during non-imaging TCD studies. We created 3D models of the basal cerebral arteries for 24 vasospasm patients. Standard acoustic windows were mapped to the specific anatomy of each patient. Virtual ultrasound transmit beams were generated that originated from the acoustic window and intersected the centerline of each arterial segment. Doppler angle measurements were calculated and compiled for each vessel segment. Doppler angles were smallest for the middle cerebral artery M1 segment (median 24.6°) and ophthalmic artery (median 25.0°), and largest for the anterior cerebral artery A2 segment (median 76.4°) and posterior cerebral artery P2 segment (median 75.8°). The ophthalmic artery had the highest proportion of Doppler angles that were less than 60° (99%) while the anterior cerebral artery A2 segment had the lowest proportion of Doppler angles that were less than 60° (10%). These angle measurements indicate the expected deviation between measured and true velocities in the cerebral arteries, highlighting specific segments that may be prone to underestimation of velocity.

Impact of Sonographer Experience, Insonation Angle, and Bladder Filling on Uterine Artery Doppler Measurements in the First Trimester of Pregnancy.

To investigate the influence of different measurement conditions and ultrasound training level on uterine artery pulsatility index (UtA-PI) measurements as required for combined first trimester preeclampsia (PE) screening. This was a prospective study of consecutive patients with singleton pregnancies presenting for an ultrasound examination between 11 and 14 weeks' gestation. UtA-PI measurements were conducted by residents in training and repeated by experienced sonographers thereafter. UtA-PI measurements were conducted under different examination conditions. First, the trainee sonographers performed transabdominal sagittal and transverse UtA-PI measurements without bladder filling. These measurements were then repeated by the expert sonographers. Additionally, the expert sonographers also performed transvaginal UtA-PI measurements and transabdominal measurements with bladder filling. Statistical analysis was conducted with the statistical software R and included descriptive statistics as well as 2-sided paired t tests. A total of 100 women were included in the study. Mean age was 31.7 ± 4.92 years and mean gestational week was 12.5 ± 0.53 weeks. A total of 56% were nulliparous and 44% were parous. UtA-PI was significantly lower if performed by a sonographer in training versus an experienced sonographer (P = .031). No significant difference was observed in comparing transverse and sagittal techniques (P = .241). There was also no significant difference in transabominal versus transvaginal measurements (P = .806) and with an empty versus full bladder (P = .444). Experience of sonographer has a significant impact on UtA-PI. Supervised onsite training is necessary to improve reliability and consistency of UtA-PI measurements and make PE screening reliable for implementation in a universal screening setting.

Assessment of volume flow rate in arteriovenous fistulas with a novel ultrasound Doppler device (earlybird): Trend analysis, comparison of methods, and inter- and intra-rater reliability.

An accessible tool is required to analyze volume flow trends in arteriovenous fistulas for hemodialysis. Earlybird, an easy-to-place ultrasound Doppler device, has shown comparable accuracy to duplex ultrasound. In this study, we compared volume flow measurements obtained with duplex ultrasound and the dilution technique to an enhanced earlybird device, featuring a dual Doppler probe system, eliminating the requirement for a known insonation angle. Nine patients with a distal radiocephalic arteriovenous fistula were monitored for 12 months with regular volume flow measurements. Correlation and inter- and intra-class reliability analyses were conducted. An overall moderate correlation was observed between earlybird and duplex ultrasound or dilution technique (intraclass correlation coefficient = 0.606 (95% confidence interval 0.064, 0.721) and 0.581 (0.039, 0.739), respectively). Duplex ultrasound compared to dilution measurements, demonstrated an overall moderate correlation (0.725 (0.219, 0.843)). Correlation between earlybird and duplex ultrasound was stronger for the arteriovenous fistula (0.778 (0.016, 0.901)) than the brachial artery (0.381 (-0.062, 0.461)). For earlybird, inter-rater reliability was excellent for the arteriovenous fistula (0.907 (0.423, 0.930)) and poor for the brachial artery (0.430 (0.241, 0.716)). Duplex ultrasound showed a good inter-rater reliability (arteriovenous fistula: 0.843 (0.610, 0.871), brachial artery: 0.819 (0.477, 0.864)). The overall intra-rater reliability was good for duplex ultrasound (rater A: 0.893 (0.727, 0.911); rater B: 0.853 (0.710, 0.891)), while excellent for earlybird (rater A: 0.905 (0.819, 0.928); rater B: 0.921 (0.632, 0.969)). We observed a weaker correlation in the measurements of volume flow rates in arteriovenous fistulas when obtained using earlybird compared to dilution technique, unlike the comparison between duplex ultrasound and the dilution technique. However, inter-rater reliability for the arteriovenous fistula was excellent with earlybird and good with duplex ultrasound, indicating the potential of earlybird as a tool for frequent measurements, enabling trend surveillance and predicting adverse outcomes.

Which left atrial volume measurement should we use in the neonatal intensive care?

BackgroundIncreased left atrial volume (LAV) is a marker of cardiovascular risk. Echocardiography standards to assess LAV in adults and children are the biplane area-length method (AL) and method of disks (MOD). LAV in neonatology is usually derived as M-mode ratio between the LA and the Aorta (LAAo). The aim of this study is to determine feasibility and reliability of these methods in neonatal clinical practice. MethodsClinically indicated echocardiograms in neonatal intensive care patients were retrospectively analyzed. Feasibility was determined with an image quality score describing insonation angle, foreshortening and wall clarity. Reliability was determined with Bland-Altman and correlation coefficient analysis of intra- and inter-observer measurements. Results104 infants ranging from 23 to 39 weeks gestation were included. The feasibility of LAAo, AL and MOD was comparable (median image score 4 out of 6 points). Linear regression between AL and MOD was excellent (R2 0.99). LAAo best-fit with MOD was reached with curve-linear regression (R2 0.28) whereby a LAAo of 1.60 correlated with 1.24 ml/kg, but with a wide 95 % CI. The correlation coefficient within and between observers for LAAo, biplane AL, biplane MOD and monoplane MOD was 0.93 (0.87–0.96), 0.98 (0.96–0.99), 0.98 (0.96–0.99), 0.99 (0.97–0.99) and 0.58 (0.11–0.81), 0.75 (0.44–0.89), 0.92 (0.88–0.98), 0.96 (0.88–0.98) respectively. ConclusionAll methods were equally feasible and reliable when repeated by the same observer, but LAAo reliability was poor when repeated by a different observer. Biplane MOD was the most reliable and thus recommended in neonatal practice. Monoplane MOD performed well and could be considered as alternative but might be less accurate.

Feasibility of teleoperated robotic echocardiography – A pilot study

PurposeEchocardiography is dependent on highly specialized healthcare professionals. Teleoperated examinations could provide higher availability of specialized care for patients living in rural areas. The objective of this study was to evaluate the feasibility of a teleoperated robotic echocardiography system. MethodsTwenty-three healthy volunteers underwent teleoperated echocardiography, compared to standard bedside echocardiography. Examination time, image quality, ability to assess cardiac structures, measurements of left ventricular fractional shortening and blood flow velocities were compared. Image quality was rated on a scale from 0 to 3. ResultsApproximately 90% of robotically acquired images were rated as medium quality or better and approximately 80% of cardiac structures were evaluated as assessable by at least one evaluator. Mean image quality was lower for robotic (1.6 ± 0.3) compared to standard clinical examinations (2.5 ± 0.4) (p = 0.001). Left ventricular fractional shortening from the robotic examinations was 2.2%, p = 0.160 (absolute value) lower compared to the reference and showed a variation coefficient of 19%. The calculated Doppler insonation angles deviated from the reference by more than 25° for three of four blood flow velocity measurements. The teleoperated examinations had a mean examination time of 26.4 min and were 1.9 times longer compared to the reference (p = 0.001). ConclusionThis feasibility study of teleoperated echocardiography shows promising results for the presented system. Clinically satisfactory imaging, particularly measurements of dimension and velocities, requires further development of the system.

Transcranial Color-Coded Sonography With Angle Correction As a Screening Tool for Raised Intracranial Pressure.

Transcranial Doppler (TCD) has been evaluated as a noninvasive intracranial pressure (ICP) assessment tool. Correction for insonation angle, a potential source of error, with transcranial color-coded sonography (TCCS) has not previously been reported while evaluating ICP with TCD. Our objective was to study the accuracy of TCCS for detection of ICP elevation, with and without the use of angle correction. Prospective study of diagnostic accuracy. Academic neurocritical care unit. Consecutive adults with invasive ICP monitors. Ultrasound assessment with TCCS. End-diastolic velocity (EDV), time-averaged peak velocity (TAPV), and pulsatility index (PI) were measured in the bilateral middle cerebral arteries with and without angle correction. Concomitant mean arterial pressure (MAP) and ICP were recorded. Estimated cerebral perfusion pressure (CPP) was calculated as estimated CPP (CPPe) = MAP × (EDV/TAPV) + 14, and estimated ICP (ICPe) = MAP-CPPe. Sixty patients were enrolled and 55 underwent TCCS. Receiver operating characteristic curve analysis of ICPe for detection of invasive ICP greater than 22 mm Hg revealed area under the curve (AUC) 0.51 (0.37-0.64) without angle correction and 0.73 (0.58-0.84) with angle correction. The optimal threshold without angle correction was ICPe greater than 18 mm Hg with sensitivity 71% (29-96%) and specificity 28% (16-43%). With angle correction, the optimal threshold was ICPe greater than 21 mm Hg with sensitivity 100% (54-100%) and specificity 30% (17-46%). The AUC for PI was 0.61 (0.47-0.74) without angle correction and 0.70 (0.55-0.92) with angle correction. Angle correction improved the accuracy of TCCS for detection of elevated ICP. Sensitivity was high, as appropriate for a screening tool, but specificity remained low.

The impact of angles of insonation on left and right ventricular global longitudinal strain estimation in fetal speckle tracking echocardiography.

Two-dimensional speckle tracking echocardiography has been considered an angle-independent modality. However, current literature is limited and inconclusive on the actual impact of angle of insonation on strain values. Therefore, the primary objective of this study was to assess the impact of angles of insonation on the estimation of fetal left ventricular and right ventricular global longitudinal strain. Secondarily, the impact of different definitions for angles of insonation was investigated in a sensitivity analysis. This is a retrospective analysis of a prospective longitudinal cohort study with 124 healthy subjects. The analyses were based on the four-chamber view ultrasound clips taken between 18+0 and 21+6 weeks of gestation. Angles of insonation were categorized into three groups: up/down, oblique and perpendicular. The mean fetal left and right ventricular and global longitudinal strain values corresponding to these three groups were compared by an ANOVA test corrected for heteroscedasticity. Fetal left and right ventricular global longitudinal strain values were not statistically different between the three angles of insonation (p-value >0.062 and >0.149, respectively). When applying another definition for angles of insonation in the sensitivity analysis, the mean left ventricular global longitudinal strain value was significantly decreased for the oblique compared to the up/down angle of insonation (p-value 0.041). There is no evidence of a difference in fetal left and right ventricular global longitudinal strain between the different angles of insonation in fetal two-dimensional speckle tracking echocardiography.

Real-time Remote Expert-guided Echocardiography by Medical Students

BackgroundEchocardiography is a highly specialised examination performed by experienced healthcare professionals. These experienced healthcare professionals may not be available to patients during all hours in rural healthcare facilities. Remote-guided echocardiography could improve the availability of specialised care for patients living in rural areas. This study examined the feasibility of real-time remote guidance for medical students to perform an echocardiographic assessment of the left side of the heart. Thirteen healthy volunteers were recruited for remote-guided echocardiography, which was performed by 13 medical students. Student examinations/images were compared to reference echocardiography. Measurements of left ventricular fractional shortening and mitral valve blood flow velocity were also compared. Furthermore, guidance through a smartphone videoconference was compared to designated remote guidance software.ResultsTwo-thirds of the images acquired by students were rated as medium or good quality and usable to evaluate two thirds of the cardiac structures. No significant bias was found for left ventricular fractional shortening. The measurements from the students’ exams had a variation coefficient of 14.8% compared to the reference. The calculated deviation of the insonation angle was above 25° for both E and A-wave mitral valve blood flow velocity measurements. Images acquired by guidance through smartphone videoconference were of lower quality than those obtained using the designated remote guidance software.ConclusionReal-time remote-guided echocardiography performed by medical students has limited value for clinical screening but could be useful for educational purposes.Graphical

ISUOG Practice Guidelines (updated): fetal cardiac screening.

ISUOG Practice Guidelines (updated): fetal cardiac screening.

Motorized 3D Ultrasound and Jugular Vein Dimension Measurement on the International Space Station.

BACKGROUND: Internal jugular vein (IJV) congestion occurs during spaceflight. Historically, IJV distension on the International Space Station (ISS) has been quantified using single slice cross-sectional images from conventional 2D ultrasound with remote guidance. Importantly, the IJV is an irregular shape and highly compressible. Consequently, conventional imaging is susceptible to poor reproducibility due to inconsistent positioning, insonation angle, and hold-down pressure, especially when controlled by novice sonographers (i.e., astronauts). Recently, a motorized 3D ultrasound was launched to the ISS that mitigates angulation errors and has a larger design, allowing for more consistent hold-down pressure and positioning. This short communication compares IJV congestion measured with 2D vs. 3D methods during spaceflight.METHODS: IJV was measured prior to and following a 4-h venoconstrictive thigh cuff countermeasure. Data were acquired from three astronauts approximately halfway through their 6-mo missions.RESULTS: The 2D and 3D ultrasound results were not congruent in all astronauts. 3D ultrasound confirmed that the countermeasure reduced IJV volume in three astronauts by approximately 35%, whereas 2D data were more equivocal. These results indicate that 3D ultrasound provides less error-prone quantitative data.DISCUSSION: These data are the first to compare 2D and 3D methods during spaceflight in the same participants by using a known countermeasure that reduces IJV congestion. The current results demonstrate that 3D ultrasound should be the preferred imaging method when trying to measure venous congestion in the IJV, and that 2D ultrasound results should be interpreted with caution.Patterson C, Greaves DK, Robertson A, Hughson R, Arbeille PL. Motorized 3D ultrasound and jugular vein dimension measurement on the International Space Station. Aerosp Med Hum Perform. 2023; 94(6):466-469.

The AIUM Practice Parameter for the Performance of the Musculoskeletal Ultrasound Examination.

The AIUM Practice Parameter for the Performance of the Musculoskeletal Ultrasound Examination.

Insonation angle impact on micro-Doppler evaluation in cerebrovascular surgery: technical note

Introduction: The insonation angle consideration is important in the Doppler-sonographic evaluation of blood flow velocities and volume, however, the concept is rarely applied to the intraoperatively used micro-Doppler.This technical note aims to emphasize the possibility and necessity of insonation angle correction and preservation for the blood flow assessment in cerebrovascular surgery.Methods: Bi-directional surgical Doppler with a 20MHz flexible bayonet 1.2mm diameter probe was used for the intraoperative blood flow assessment, with the variable insonation angle on the straight parts of the arteries, and the results were recorded to demonstrate the importance.Results: The measurements performed confirmed that the blood flow features, including the direction, velocity, and especially the volume, are highly susceptible to the insonation angle variations. Although there were significant alterations, positioning the probe at an angle of ~60 degrees resulted in the variable but less altering measurements.Conclusion: Positioning the probe at ~60 degrees is desirable; however, it appears that it is even more important to maintain the same insonation angle and probe position when assessing the vessels repeatedly for blood flow alterations that might occur in the course of cerebrovascular surgery.

Modeling of Ultrasound Stimulation of Adolescent Pancreas for Insulin Release Therapy.

Our previous published studies have focused on safety and effectiveness of using therapeutic ultrasound (TUS) for treatment of type 2 diabetes mellitus (T2DM) in preclinical models. Here we present a set of simulation studies to explore potential ultrasound application schemes that would be feasible in a clinical setting. Using the multiphysics modeling tool OnScale, we created two-dimensional (2D) models of the human abdomen from CT images captured from one normal weight adolescent patient, and one obese adolescent patient. Based on our previous studies, the frequency of our TUS was 1MHz delivered from a planar unfocused transducer. We tested five different insonation angles, as well as four ultrasound intensities combined with four different duty factors and five durations of application to explore how these variables effect the peak pressure and temperature delivered to the pancreas as well as surrounding tissue in the model. We determined that ultrasound applied directly from the anterior of the patient abdomen at 5W/cm2 delivered consistent acoustic pressures to the pancreas at the levels which we have previously found to be effective at inducing an insulin release from preclinical models. Our modeling work indicates that it may be feasible to non-invasively apply TUS in clinical treatment of T2DM.

Ultrasound insonation angle and scanning imaging modes for imaging dental implant structures: A benchtop study.

High frequency ultrasound has shown as a promising imaging modality to evaluate peri-implant tissues. It is not known if the ultrasound imaging settings might influence ultrasound's ability to differentiate implant structures. The aim of this benchtop study was to evaluate the dependence of ultrasound on imaging angles and modes to measure implant geometry-related parameters. A clinical ultrasound scanner (ZS3, Mindray) with an intraoral probe (L30-8) offering combinations of harmonic and compound imaging modes was employed for imaging 16 abutments and 4 implants. The samples were mounted to a micro-positioning system in a water tank, which allowed a range of -30 to 30-degree imaging angles in 5-degree increment between the probe and samples. The abutment angle, implant thread pitch and depth were measured on ultrasound, compared to the reference readings. The errors were computed as a function of the image angles and modes. All samples were replicated 3 times for 3 image modes and 11 image angles, thus resulting in 2,340 images. The mean errors of ultrasound to estimate 16 abutment angles, compared to the reference values, were between -1.8 to 2.7 degrees. The root mean squared error (RMSE) ranged from 1.5 to 4.6 degrees. Ultrasound significantly overestimated the thread pitch by 26.1 μm to 36.2 μm. The error in thread depth measurements were in a range of -50.5 μm to 39.6 μm, respectively. The RMSE of thread pitch and depth of the tested 4 implants was in a range of 34.7 to 56.9 μm and 51.0 to 101.8 μm, respectively. In most samples, these errors were independent of the image angle and modes. Within the limitations of this study, high-frequency ultrasound was feasible in imaging abutments and implant fixtures independent of scanning angle within ±30° of normal incidence and for compounding and non-compounding-based imaging modes.

Minute Stroke Distance Is a More Reproducible Measurement Than Cardiac Output in the Assessment of Fetal Ventricular Systolic Function

Echocardiographic quantification of fetal cardiac output (CO) aids clinical decision-making in the management of various cardiac and extracardiac diseases. Small variability in measuring semilunar valve dimension significantly reduces the reproducibility of the calculated CO. The authors propose minute stroke distance or velocity-time integral (VTI) as a more reproducible measure reflecting fetal ventricular systolic function. The aim of this study was to test the hypothesis that right and left ventricular minute VTI increase predictably with estimated fetal weight and are more reproducible than CO. Five hundred seventy-one singleton fetuses without cardiovascular pathology between 16 and 36weeks' gestation were reviewed retrospectively. Twenty-two fetuses with pathology resulting in low- or high-CO states were also assessed for comparison. VTI was measured in both ventricular outflow tracts at the level of the semilunar valve, excluding a Doppler insonation angle of >30°. Heart rate, semilunar valve dimension, and VTI determined minute VTI and CO. Inter- and intrarater variability were evaluated in a random 10% subset. Minute VTI and CO measurements were feasible in 67% to 89% of fetuses in this retrospective study. Minute VTI and CO increased with estimated fetal weight nonlinearly (R=0.61-0.94). The mean inter- and intrarater variability for VTI, 6% and 5.7%, were significantly less than for CO, 25% and 23.7% (P<.001 for all). Minute VTI is an easily measured, highly reproducible method of quantifying fetal ventricular systolic function. Variability in calculated CO from valve measurement differences is minimized by solely using VTI. Nomograms of minute VTI provide an efficient and precise assessment of fetal systolic function and may be used to track fetuses in disease states with low or high CO.

2D speckle tracking: a diagnostic and prognostic tool of paramount importance.

We aimed to conduct a review of the literature relevant to cardiac imaging techniques and summarize the use of different non-invasive imaging modalities in the assessment of ventricular size, function, and mechanics. The current review emphasizes the benefits of speckle tracking imaging (STI), highlighting its use in demonstrating myocardial strain. This robust technique is a recent addition to the existing imaging techniques that are used to assess the myocardium. In terms of effectively determining the left ventricle ejection fraction, it is a comparable technique to cardiac magnetic resonance. The use of STI method for image acquisition relies on semiautomatic identification of the border and deformation of the region of interest, and is also independent of the angle of insonation, thus it increases the inter-and intra-observer reproducibility in contrast to the conventional tissue doppler imaging. The databases of PubMed, Scopus, and Embase were thoroughly searched for the following keywords: 2- dimensional/ two-dimensional/ 2-D, speckle/strain tracking, systolic dysfunction, and heart failure. The studies selected described image acquisition techniques and the application of this imaging modality in various clinical settings. The selected journal articles were perused to provide the best possible analysis of STI. Our comparative analysis demonstrated that the STI, when compared with the conventional echocardiography, is a more sensitive image acquiring technique for detecting subclinical myocardial dysfunction. Based on the analysis it can be stated that the STI can provide valuable information on both regional and global myocardial function, and it can also quantify cardiac synchronicity and rotation. Additionally, it serves as a better prognostic indicator. The change in longitudinal strain can serve as an early marker of the left ventricular systolic dysfunction, and therefore, monitoring via STI has both diagnostic and prognostic value in heart failure, ischemic heart disease, valvulopathies, chemotherapy-induced cardiotoxicity, and cardiac resynchronization therapy. Despite the lack of standardization, the method is also effective in assessing the right ventricle and left atrial function and arterial rigidity.

Reliability of Third Ventricle Assessment by Transcranial Ultrasound: A Computational Model of the Effect of Insonation Angle.

Transcranial sonography (TCS) is a bedside examination which is currently used in multiple neurocritical care settings. Third ventricle ultrasound is usually a simple technique, though a large insonation angle could lead to an overestimation of third ventricular diameter. The aim of this study was to use a mathematical model to evaluate the impact of probe inclination on the false positive rate when using TCS to evaluate third ventricle enlargement. Using R software, we simulated a pool of 100,000 fictitious patients with a normal third ventricle size (diameter from 0 to 9 mm) in daily follow-up for ventricle enlargement for 30 consecutive days using TCS. Each day, a different, random insonation angle (α) was generated and a corresponding measured diameter calculated as: measured diameter=real diameter/cos α. If the measured diameter was >9.0 mm, the simulation registered a "misdiagnosis" episode and the simulation loop was interrupted; otherwise, the simulation continued to its thirtieth iteration. Of the 100,000 "patient" simulations, 30,905 (30.9%) had an erroneous TCS diagnosis of ventricular enlargement. Angles of insonation >35 degrees contributed to 79.3% of the total misdiagnoses of ventricular enlargement (false positive rate, 3.71%), whereas misdiagnosis was rare when the insonation angle was ≤15 degrees (1.30% of the total misdiagnoses; false positive rate, 0.06%). Using probe inclinations <15 degrees, erroneous diagnosis of third ventricular enlargement was rare. Our results suggest that TCS has a low rate of false positives when the angle of insonation is minimized.

68 Late Gestational Nutrient Restriction Decreases Blood Flow to the Mammary Gland in Lactating Primiparous Beef Females

Abstract To determine the effects of late gestational nutrient restriction on mammary blood flow during lactation, fall-calving Hereford-SimAngus heifers (single-sired; BW: 451 ± 28 [SD] kg; BCS: 5.4 ± 0.7) bred to a single sire were individually-fed 100% (control; CON; n = 10) or 70% (NR; n = 13) of NASEM net energy and metabolizable protein requirements for maintenance, pregnancy, and growth from d 160 of gestation to calving. Post-calving, all females were individually fed chopped tall fescue hay supplemented to meet lactational nutrient requirements in Calan gates. Transrectal color Doppler ultrasonography of both external pudendal arteries was conducted every 21 d from d 23 to 107 of lactation. Total mammary blood flow was calculated and hemodynamics from both sides averaged. Data were analyzed with fixed effects of nutritional plane, day of lactation, and their interaction, using repeated measures. Calving date and calf sex (if P &amp;lt; 0.25) were fixed effects, and Doppler angle of insonation was included in the model for flow-related variables. We have previously reported that CON cows had greater (P ≤ 0.003) BW, BCS, and backfat from calving to d 147 of lactation, and NR cows had 15% less (P &amp;lt; 0.04) milk yield. External pudendal artery pulsatility index tended to be greater (P = 0.06) and resistance index, peak systolic velocity, and cross-sectional area were greater (P ≤ 0.04) in CON cows. Heart rate was greater (P = 0.008), yet mammary blood flow was 19% less (P = 0.004) in NR cows. Mammary blood flow/cow BW and blood flow/milk yield were not affected (P ≥ 0.13) by nutritional plane. All hemodynamic variables were affected by day (P ≤ 0.04) except resistance index (P = 0.11). In summary, late gestational nutrient restriction decreased mammary blood flow similarly to the reduction observed in milk yield.

Prospective study comparing simultaneous transthoracic and transesophageal echocardiography aortic stenosis assessment

Abstract Funding Acknowledgements Type of funding sources: None. Background Transthoracic echocardiography (TTE) is the gold-standard for aortic stenosis (AS) assessment. Transesophageal echocardiography (TEE) can be used alternatively, but measurement of hemodynamic components can be affected. Purpose We aimed to compare head-to-head TTE vs transesophageal echocardiography (TEE) assessment of AS. Methods We prospectively studied 56 patients with ≥moderate AS who underwent TTE (TTE1) and consecutive conscious sedation with simultaneous TEE and TTE (TTE2). Echocardiographic variables and AS types measured by TEE vs TTE2 and by TEE vs TTE1 were compared using paired tests and chi square tests. Based on conservative vs actionable implication, AS types were dichotomized into Group-A, comprising moderate and Normal-Flow Low-Gradient, and Group-B, comprising High-Gradient, Low Ejection-Fraction Low-Flow Low-Gradient, and Paradoxical Low-Flow Low-Gradient AS. Results TEE vs simultaneous TTE2 comparison demonstrated higher mean gradients (31.7 ± 10.5 vs 27.4 ± 10.5mmHg) and velocities (359 ± 60.6 vs 332 ± 63.1cm/sec) with TEE, but lower left ventricular outflow velocity-time-integral VTI1 (18.6 ± 5.1 vs 20.2 ± 6.1cm), all p &amp;lt; 0.001. This resulted in lower aortic valve area AVA (0.8 ± 0.21 vs 0.87 ± 0.28cm2), p &amp;lt; 0.001, and a net relative-risk of 1.86 of Group A to B upgrade. TEE vs (awake-state) TTE1 comparison revealed a larger decrease in VTI1 due to higher initial awake-state VTI1 (22 ± 5.6cm), resulting in similar Doppler-velocity-index (DVI) and AVA decrease with TEE, despite slight increase in mean gradients of 0.8mmHg (-1.44 to 3.04 CI) and in velocities of 10cm/sec (-1.5 to 23.4 CI). This translated into a net relative-risk of 1.92 of Group A to B upgrade vs TTE1. Conclusions TEE under conscious sedation overestimates AS severity compared with both awake state TTE and simultaneous sedation state TTE, accounted for by different Doppler insonation angle obtained in transapical vs transgastric position. The net result is a smaller DVI and AVA by TEE vs TTE. TEE carries a high sensitivity but a low specificity for severe AS compared with TTE during awake state. Abstract Figure. Spectral Doppler w/TTE vs simultan. TEE Abstract Figure. Cardiac CT planes simulating TTE vs TEE

High frame rate blood speckle tracking echocardiography: left ventricle vortex analyisis in healthy children and in congenital heart disease

Abstract Funding Acknowledgements Type of funding sources: None. Background High-frame rate blood speckle tracking (BST) echocardiography is a new method, for the evaluation of intracardiac flow, independent of the insonation angle. Left ventricle, throughout cardiac cycle, creates a vortical flow still poorly analysed in children with congenital heart disease (CHD). Aim of this study is to evaluate the characteristics of left ventricular (LV) vortices in healthy children and in those with CHD. Methods Characteristics of LV vortices were acquired on standard 4-chamber view and BST images from 230 healthy children (median age 5.96 years, range 2.9-10.1 years) and 72 children with CHD (median age 1.33 years, IQR 0.2-7.12 years). Both groups were compared after propensity matching. Multiple linear regression was used to identify factors that independently influence vortex characteristics. Results Feasibility of vortex imaging was 97% for healthy children and 96.7% for CHD. After propensity matching, there were mild significant differences in vortex distance to apex, distance to interventricular septum, height, width, sphericity index. Indexed by BSA Vortex Area (VAi) was significantly higher on CHD patients than healthy subjects (p &amp;lt; 0.0001). However, multiple regression analysis exposed significant associations of LV morphology with vortex characteristics: a VAi &amp;gt;0.98 can predict an abnormal LV morphology (Sensibility 73%, Specificity 83%). Furthermore, CHD involving LV volume or pressure overload were both associated with vortices localized closer to the IVS. Conclusions LV vortex analysis using high-frame rate BST echocardiography is feasible in healthy children and in those with CHD. Since vortices are associated with LV morphology and are altered in some CHDs, vortices might yield diagnostic and prognostic value. Future studies are necessary to further establish applications of vortex imaging in the clinical setting. Abstract Figure. Vortex in healthy children and in CHD