Forward Volume Research Articles

Prognostic value of depressed cardiac index after STEMI: a phase-contrast magnetic resonance study

Abstract Funding Acknowledgements Type of funding sources: None. Aims An invasively measured Cardiac Index (CI) of ≤2.2 l/min/m² is one of the strongest prognostic indicators after ST-elevation myocardial infarction, however knowledge is mainly based on invasive evaluations performed in the pre-stent era. Velocity-encoded Phase Contrast Cardiac Magnetic Resonance (PC-CMR) allows non-invasive determination of CI. Methods In this prospective study CMR was performed in 406 stable and contemporarily revascularized patients a median of 3 days after STEMI. Forward stroke volume was assessed at the level of the ascending aorta by PC-CMR. Left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) were determined by cine CMR. Major adverse cardiac events (MACE) were defined as the composite of death, myocardial infarction or hospitalization for heart failure. Results Median CI was 2.52 l/min/m², 27% of patients had ≤2.2 l/min/m². Median LVEF was 53%, median GLS was -12.2%. During a median follow-up of 13.6 (12.1;62.9) months, 38 patients (8.7%) experienced a MACE. A depressed CI was significantly associated with MACE after adjustment for GLS and LVEF (HR = 2.55 (95%CI 1.10—5.28); p = 0.01), markers of myocardial injury (HR = 2.18, 95%CI 1.10-4.30, p = 0.02) and clinical parameters (HR = 2.42, 95%CI 1.19-4.90, p = 0.01). Adding CI to a model including LVEF and GLS led to significant discrimination improvement (0.55 [95%CI 0.18 - 0.91]; p = 0.003). Conclusions A CI of 2.2 l/min/m² or less as measured by PC-CMR was present in 27% of clinically stable patients after STEMI, which strongly and independently predicted medium-term MACE. The prognostic value of a depressed CI was superior and incremental to LVEF and GLS. Abstract Figure. Graphical Abstract

Discriminating Reflux from Non-Reflux Diseases of Superficial Veins in Legs by Novel Non-Contrast MR with QFlow Technique.

Objectives: To find an objective diagnostic tool for the superficial veins in legs. Methods: This study included 137 patients who underwent TRANCE-MRI from 2017 to 2020 (IRB: 202001570B0). Among them, 53 with unilateral leg venous diseases underwent a QFlow scan and were classified into the reflux and non-reflux groups according to the status of the great saphenous veins. Results: The QFlow, namely stroke volume (SV), forward flow volume (FFV), mean flux (MF), stroke distance (SD), and mean velocity (MV) measured in the external iliac, femoral, popliteal, and great saphenous vein (GSV). The SV, FFV, SD, MF, SD, and MV in the GSV (morbid/non-morbid limbs) demonstrated a favorable ability to discriminate reflux from non-reflux in the ROC curve. The SD in the GSV and GSV/PV ratio (p = 0.049 and 0.047/cutoff = 86 and 117.1) and the MV in the EIV/FV ratio, GSV, and GSV/PV ratio (p = 0.035, 0.034, and 0.025/cutoff = 100.9, 86.1, and 122.9) exhibited the ability to discriminate between reflux and non-reflux group. The SD, MV, and FFV have better ability to discriminate a reflux from non-reflux group than the SV and MF. Conclusions: QFlow may be used to verify the reflux of superficial veins in the legs. An increasing GSV/PV ratio is a hallmark of reflux of superficial veins in the legs.

Direct mitral regurgitation quantification in hypertrophic cardiomyopathy using 4D flow CMR jet tracking: evaluation in comparison to conventional CMR

BackgroundQuantitative evaluation of mitral regurgitation (MR) in hypertrophic cardiomyopathy (HCM) by cardiovascular magnetic resonance (CMR) relies on an indirect volumetric calculation. The aim of this study was to directly assess and quantify MR jets in patients with HCM using 4D flow CMR jet tracking in comparison to standard-of-care CMR indirect volumetric method.MethodsThis retrospective study included patients with HCM undergoing 4D flow CMR. By the indirect volumetric method from CMR, MR volume was quantified as left ventricular stroke volume minus forward aortic volume. By 4D flow CMR direct jet tracking, multiplanar reformatted planes were positioned in the peak velocity of the MR jet during systole to calculate through-plane regurgitant flow. MR severity was collected for agreement analysis from a clinical echocardiograms performed within 1 month of CMR. Inter-method and inter-observer agreement were assessed by intraclass correlation coefficient (ICC), Bland–Altman analysis, and Cohen’s kappa.ResultsThirty-seven patients with HCM were included. Direct jet tracking demonstrated good inter-method agreement of MR volume compared to the indirect volumetric method (ICC = 0.80, p = 0.004) and fair agreement of MR severity (kappa = 0.27, p = 0.03). Direct jet tracking showed higher agreement with echocardiography (kappa = 0.35, p = 0.04) than indirect volumetric method (kappa = 0.16, p = 0.35). Inter-observer reproducibility of indirect volumetric method components revealed the lowest reproducibility in end-systolic volume (ICC = 0.69, p = 0.15). Indirect volumetric method showed good agreement of MR volume (ICC = 0.80, p = 0.003) and fair agreement of MR severity (kappa = 0.38, p < 0.001). Direct jet tracking demonstrated (1) excellent inter-observer reproducibility of MR volume (ICC = 0.97, p < 0.001) and MR severity (kappa = 0.84, p < 0.001) and (2) excellent intra-observer reproducibility of MR volume (ICC = 0.98, p < 0.001) and MR severity (kappa = 0.88, p < 0.001).ConclusionsQuantifying MR and assessing MR severity by indirect volumetric method in HCM patients has limited inter-observer reproducibility. 4D flow CMR jet tracking is a potential alternative technique to directly quantify and assess MR severity with excellent inter- and intra-observer reproducibility and higher agreement with echocardiography in this population.

4D flow MRI: impact of region of interest size, angulation and spatial resolution on aortic flow assessment

Objectives. In cardiovascular magnetic resonance, the 3D time-resolved phase-contrast technique, also known as 4D flow, is gaining increasing attention due to applications that exploit three-directional velocity encoding throughout the cardiac cycle. Blood flow volume assessment usually requires an expert to draw regions of interest (ROI) around the vessel cross section, whereas the errors involved in this estimation have not been thoroughly investigated. Our objective is to quantify the influence of ROI sizing, angulation and spatial resolution of the reconstructed plane employed in blood flow measurements using 4D flow. Approach. Three circular ROIs were drawn around the ascending, arch and descending aorta of healthy volunteers (n = 27) and patients with a dilated ascending aorta or bicuspid valve (n = 37). We applied systematic changes of ROI diameter (up to ±10%), tilt angle (up to ±25°) and spatial resolution (from 0.25 to 2 mm) of the reconstructed oblique planes, calculating the effects on net, forward and backward blood flow volumes. Main results. Patients had a larger ascending aorta than healthy volunteers with similar ages and male sex proportion (60 ± 15 y.o. vs 58 ± 16 y.o. and 84% vs 70%, respectively). Higher forward and backward flow volumes were observed in the ascending aorta and the aortic arch of the patients with respect to controls (p < 0.001), whereas net volumes were similar: 74.0 ± 20.8 ml versus 75.7 ± 21.8 ml (p = 0.37), respectively. The ascending aorta was the most sensitive to ROI modifications. Changes of ±10% in the ROI diameter and ±25° in tilt angles produced flow volume differences of up to 9 ml (10%) and 18 ml (15%) in controls and patients, respectively. Modifying the reconstructed planes spatial resolution produced flow volume changes below 2 ml. Significance. Since the setting of the ROI size and plane angle could produce errors that represent up to 20% of the forward and/or backward aortic flow volume, a good standardization for vessel segmentation and plane positioning is desirable.

Multicenter Consistency Assessment of Valvular Flow Quantification With Automated Valve Tracking in 4D Flow CMR

ObjectivesThis study determined: 1) the interobserver agreement; 2) valvular flow variation; and 3) which variables independently predicted the variation of valvular flow quantification from 4-dimensional (4D) flow cardiac magnetic resonance (CMR) with automated retrospective valve tracking at multiple sites. BackgroundAutomated retrospective valve tracking in 4D flow CMR allows consistent assessment of valvular flow through all intracardiac valves. However, due to the variance of CMR scanners and protocols, it remains uncertain if the published consistency holds for other clinical centers. MethodsSeven sites each retrospectively or prospectively selected 20 subjects who underwent whole heart 4D flow CMR (64 patients and 76 healthy volunteers; aged 32 years [range 24 to 48 years], 47% men, from 2014 to 2020), which was acquired with locally used CMR scanners (scanners from 3 vendors; 2 1.5-T and 5 3-T scanners) and protocols. Automated retrospective valve tracking was locally performed at each site to quantify the valvular flow and repeated by 1 central site. Interobserver agreement was evaluated with intraclass correlation coefficients (ICCs). Net forward volume (NFV) consistency among the valves was evaluated by calculating the intervalvular variation. Multiple regression analysis was performed to assess the predicting effect of local CMR scanners and protocols on the intervalvular inconsistency. ResultsThe interobserver analysis demonstrated strong-to-excellent agreement for NFV (ICC: 0.85 to 0.96) and moderate-to-excellent agreement for regurgitation fraction (ICC: 0.53 to 0.97) for all sites and valves. In addition, all observers established a low intervalvular variation (≤10.5%) in their analysis. The availability of 2 cine images per valve for valve tracking compared with 1 cine image predicted a decreasing variation in NFV among the 4 valves (beta = −1.3; p = 0.01). ConclusionsIndependently of locally used CMR scanners and protocols, valvular flow quantification can be performed consistently with automated retrospective valve tracking in 4D flow CMR.

Long-term outcome after transcatheter mitral annuloplasty for secondary mitral regurgitation

Abstract Funding Acknowledgements Type of funding sources: None. Background The long-term effects of transcatheter mitral valve annuloplasty (TMVA) for secondary mitral regurgitation is unknown. Purpose We studied the clinical outcome and the effects on left ventricular (LV) function and remodeling and on mitral regurgitation (MR) severity after TMVA using the Carillon annuloplasty device. Methods We analyzed 33 consecutive patients with symptomatic MR who were treated with TMVA at Leipzig University Hospital between 2012 and 2018. Echocardiography was performed before TMVA and at follow-up. MR severity was quantitatively assessed by regurgitant volume (calculated as LV total stroke volume – LV forward stroke volume) and regurgitant fraction (calculated as regurgitant volume / LV total stroke volume). Results Mean age was 80 ± 10 years, 19 patients were women. A Society of Thoracic Surgeons (STS) score of 8.1 ± 7.2% indicated high risk status for mitral valve surgery. In 26 patients, mitral regurgitation resulted from LV remodeling and LV dysfunction, 7 suffered from left atrial dilatation. LV ejection fraction at baseline was 38% (30-49%; median, interquartile range). During a mean follow-up time of 45 ± 20 months, 17 patients died, 2 patients withdraw consent, and 4 patients were lost. Of the remaining patients, 4 were hospitalized for decompensated heart failure, and 2 underwent additional transcatheter edge-to-edge mitral valve repair. At follow-up, NYHA functional class improved from 95% in class III/IV at baseline to 70% in class I/II with no patients in NYHA class IV (p &amp;lt; 0.0001). Mitral regurgitant volume was reduced from 27mL (25-42mL) to 8mL (3-17mL) (p = 0.035) and regurgitant fraction from 43% (32-54%) to 11% (8-24%) (p = 0.020). LV end-diastolic volume index (92mL/m2 (71-107mL/m2) vs. 67mL/m2 (46-101mL/m2), p = 0.084) and end-systolic volumes index (51mL/m2 (44-69mL/m2) vs. 32mL/m2 (20-53mL/m2), p = 0.037) decreased. Thus, total stroke volume remained similar (38mL/m2 (33-43mL/m2) vs. 33mL/m2 (26-44mL/m2), p = 0.695) while LV ejection fraction increased (43% (31-49%) vs. 54% (46-57%), p = 0.032). Forward stroke volume, heart rate and forward cardiac output remained unchanged. Blood pressure was similar at baseline and at follow-up. Conclusion. Among high risk patients undergoing transcatheter mitral valve annuloplasty for symptomatic secondary MR, mortality was about 50% at 4 years. In the surviving patients, reduced MR severity was associated with fewer heart failure symptoms, reverse LV remodeling and improved LV function.

Spin wave propagation in a ferrimagnetic thin film with perpendicular magnetic anisotropy

Iron garnets as an important type of low-damping magnetic insulator can provide an ideal platform for the field of magnonics. In this work, we study the propagation of spin waves in a 60 nm-thick TmIG film with perpendicular magnetic anisotropy using all-electrical spin wave spectroscopy. The magnetostatic forward volume mode spin waves show a fully reciprocal propagation. By sweeping out-of-plane magnetic fields in the low-field regime, spin textures are created and observed; meanwhile, the spin wave mode vanishes, which indicates that propagating spin waves are filtered by the spin textures. By applying a large in-plane field, spin wave propagation in a Damon–Eshbach configuration is studied. Our findings provide a potential method to explore reconfigurable magnonic devices.

Abstract 17002: Assessment of Exercise Function in Children With Hypertrophic Cardiomyopathy

Introduction: Hypertrophic cardiomyopathy (HCM) accounts for nearly half of pediatric cardiomyopathies. While impaired exercise function has been described in adults with HCM, little is known about exercise function in children with HCM. Hypothesis: Children with HCM have impaired exercise function. Methods: A retrospective cohort study was performed. Pts &lt;21 years with a diagnosis of HCM with a cardiopulmonary exercise test (CPET) between November 1, 2002 and May 31, 2019 were included. Pts with syndromic HCM were excluded. CPETs with respiratory exchange ratio &lt;1.09 were excluded. We compared indices of exercise performance to established population normal values using one-sample T-tests. In pts with multiple CPETs, we compared indices of exercise performance from the first to last CPET using paired T-tests. Results: We identified 124 pts with 240 CPETs. The average age at time of CPET was 14.8 ± 3.0 years. Average %predicted peak VO2 (78 ± 20%) was significantly less than the population average (p &lt;0.01), though there was wide variability (range 35-152% predicted). Peak VO2 was &lt;85% predicted in 67%, &lt;50% predicted in 7%, and absolute peak VO2 was &lt;25 cc/kg/min in 30% of tests. However, %predicted peak VO2 was &gt;100% in 13% of tests. The %predicted peak O2 pulse (88 ± 21%; p &lt;0.01; a surrogate for the forward stroke volume at peak exercise) and the %predicted peak heart rate (88.0 ± 12%; p &lt;0.01) were significantly lower than established population normal values. In 63 pts with multiple CPETs, significant declines in %predicted peak VO2 (83 ± 20% v. 75 ± 19%; p &lt;0.01) and O2 pulse (92 ± 22% v. 86 ± 21%; p &lt;0.01) were observed at an average interval of 4.5 years. We found no statistically significant association between %predicted peak VO2 and interventricular septal thickness, resting left ventricular outflow tract gradient or echocardiographic indices of diastolic left ventricular function. Conclusions: Exercise function is at least moderately impaired in a substantial portion of children with HCM and this impairment tends to worsen over time. However, there is a significant subset of patient with remarkably well-preserved exercise function. Echocardiographic measurements did not correlate with exercise function in our cohort.

Abstract 13429: Echocardiographic Predictors of Mitral Transvalvular Gradients After Mitraclip Insertion

Introduction: The MitraClip procedure is a non-surgical alternative for patients with severe mitral regurgitation and high surgical risk. However, the MitraClip may lead to a reduction in the mitral valve orifice area (MVOA) and elevated transmitral mean gradients (TMG). The objectives of this study are to assess the value of baseline MVOA by different imaging methods and explore the value of MVOA indexed for left ventricular (LV) forward stroke volume (SV) to predict postprocedural TMG. Methods: Preprocedural echo images were retrospectively reviewed in 76 consecutive patients. MVOA from 2D transthoracic (MVOA TTE ), 2D transgastric (MVOA TG ) and 3D transesophageal (MVOA 3D ) echocardiography were measured and then indexed by the SV measured by Doppler in the LV outflow tract (MVOA/SV) . Postprocedural TMG was measured at one month and survival rate at one year. Results: Patients with postprocedural TMG &gt;5 mmHg (18/76, 24%) had significantly smaller preprocedural MVOA 3D (3.9±0.9 vs 5.2±1.3 cm 2 , p&lt;0.01) and MVOA TTE (4.9±1.1 vs 5.9±1.5 cm 2 , p=0.02). No significant difference was found for MVOA TG (5.5±1.4 vs 5.9±1.4 cm 2 , p=0.2). Best threshold values for MVOA 3D and MVOA TTE to predict postprocedural TMG &gt;5 mmHg were respectively 3.9 cm 2 (AUC=0.80, IC95%: 0.67-0.94, p&lt;0.01; sensitivity (Se) 62%, specificity (Sp) 87%) and 4,6 cm 2 (AUC=0.69, IC95%: 0.54-0.83, p=0.02; Se 50%, Sp 84%). MVOA/SV from each echocardiographic modality were smaller in patients with postprocedural TMG &gt;5 mmHg (3D: 80 [62-95] vs 113 [99-129] cm 2 /L; TTE: 92 [81-105] vs 130 [100-166] cm 2 /L; TG: 104 [83-123] vs 135 [104-166] cm 2 /L; p&lt;0.01 for all). MVOA/SV 3D was overall the best predictor of postprocedural TMG &gt;5 mmHg, with an optimal threshold of 96 cm 2 /L (AUC=0.86, IC95%: 0.76-0.97, p&lt;0.001; Se 84%, Sp 81%). Patients with MVOA 3D &lt;3.9 cm 2 and MVOA/SV 3D &lt;96 cm 2 /L tend to be at higher risk for mortality at one-year follow-up (69% vs 84%, p=0.14 and 67% vs 87%, p=0.11 respectively). Conclusion: Unlike preprocedural MVOAs assessed by 3D echocardiography, preprocedural MVOAs measured by 2D echocardiographic modalities were poor predictors of high TMG after MitraClip. Preprocedural MVOA 3D &lt;3.9 cm 2 and MVOA/SV 3D &lt;96 cm 2 /L were found to be the best cut-off values to predict postprocedural TMG &gt;5 mmHg.

Electrical spectroscopy of forward volume spin waves in perpendicularly magnetized materials

We study the potential of all-electrical inductive techniques for the spectroscopy of propagating forward volume spin waves. We develop a one-dimensional model to account for the electrical signature of spin-wave reflection and transmission between inductive antennas and validate it with experiments on a perpendicularly magnetized Co/Ni multilayer. We describe the influence of the antenna geometry and antenna-to-antenna separation, as well as that of the material parameters on the lineshape of the inductive signals. For a finite damping, the broadband character of the antenna emission in the wave vector space imposes to take into account the growing decoherence of the magnetization waves upon their spatial propagation. The transmission signal can be viewed as resulting from two contributions: a first one from propagating spin-waves leading to an oscillatory phase of the broadband transmission coefficient, and another one originating from the distant induction of ferromagnetic resonance because of the long-range stray fields of realistic antennas. Depending on the relative importance of these two contributions, the decay of the transmitted signal with the propagation distance may not be exponential and the oscillatory character of the spin-wave phase upon propagation may be hidden. Our model and its experimental validation allow to define geometrical and material specifications to be met to enable the use of forward volume spin waves as efficient information carriers.

How accurate is cardiac magnetic resonance in quantitation of primary mitral regurgitation?

Abstract Background Since evaluation of mitral regurgitation (MR) in patients with mitral prolapse by echo may be challenging, cardiac MRI (CMR) has been used for identification of patients with severe valve disease. Little is known about potential factors influencing accuracy of this approach. Purpose To study the impact of left ventricular (LV) contouring methods and interobserver variability on quantitation of MR severity. Methods A total of 50 asymptomatic patients with echocardiographically moderate or severe MR were included to LV-REGURGE study and evaluated with CMR by two independent reviewers. LV volumes were calculated on SSFP short axis stack including or excluding intracavitary myocardium into/from the LV volume (“including” or “excluding” method, respectively). Aortic flow volumes were obtained using phase contrast method. Mitral regurgitant volume (RegVol) was calculated by subtracting forward aortic volume from LV stroke volume. Severe MR was diagnosed when RegVol &amp;gt;60mL and/or RegVol/LV stroke volume (RF) &amp;gt;40%. Agreement between MR grading into severe and non-severe, obtained by different tracing methods and different reviewers was assessed using kappa coefficient. Results Left ventricular and mitral regurgitant volumes obtained by “including” method were significantly larger as compared with “excluding” method, see table. “Including” method identified severe MR in 68% while “excluding” method in 57% of cases. Overall agreement between the methods was present in 84% of cases, meaning a substantial rate of agreement (κ 0.67). Within respective methods, interobserver agreement was present in 77% of cases, interpreted as a moderate rate of agreement (κ 0.48–0.54) Conclusion “Including” trabeculae and papillary muscles into the LV cavity volume substantially increases rate of recognizing severe MR, due to larger LV volumes, particularly LV ESV, comparing with the “excluding” method. Moreover, inter-observer variability in similar extent as tracing method seems to impact differentiation between severe and non-severe MR. Funding Acknowledgement Type of funding source: None

ECHOCARDIOGRAPHIC PREDICTORS OF MITRAL TRANSVALVULAR GRADIENTS AFTER MITRACLIP INSERTION

The percutaneous MitraClip system is recognized as a valuable alternative to surgery in patients with symptomatic mitral regurgitation (MR) and prohibitive surgical risk. However, the MitraClip procedure may lead to a reduction in the mitral valve orifice area (MVOA) and increased transmitral mean gradients (TMG). Although preprocedural MVOA≤4 cm2 is considered a relative contraindication for the procedure; predictors of post-intervention TMG are not well known and TMG is also influenced by transvalvular flow. The objectives of this study are to assess the value of baseline MVOA by different imaging methods and explore the value of MVOA indexed for left ventricular forward stroke volume (SV) to predict post-intervention TMG.

Evaluation of Mesorectal Microcirculation With Quantitative Dynamic Contrast-Enhanced MRI.

OBJECTIVE. The purpose of this study was to use quantitative dynamic contrast-enhanced MRI (DCE-MRI) to evaluate mesorectal microcirculation in patients with rectal cancer. MATERIALS AND METHODS. A total of 53 patients with semicircular rectal tumors underwent DCE-MRI with a 3-T MRI system before surgery. ROIs were manually delineated in the mesorectum that surrounded the tumor and the mesorectum that surrounded the normal rectal wall. DCE-MRI parameters including forward volume transfer constant (Ktrans), reverse volume transfer constant (kep), and fractional extravascular extracellular space volume (Ve) were estimated using computer software. Histopathologic analysis served as the standard reference. RESULTS. Mesorectum that surrounded the tumor showed significantly higher Ktrans val ues than mesorectum that surrounded normal rectal wall (mean, 0.069 ± 0.035 [SD] vs 0.039 ± 0.020 min-1; p < 0.001). The tumor-surrounding mesorectum also showed higher Ve values than normal mesorectum (p < 0.001). An opposite trend was observed for kep, but this was not significant (p = 0.077). A lower Ktrans of the tumor-surrounding mesorectum was observed in patients with malignant lymph nodes compared with those with benign lymph nodes (mean, 0.054 ± 0.027 vs 0.076 ± 0.036 min-1; p = 0.034). Although kep values for the tumor-surrounding mesorectum were higher in patients with tumors categorized as pathologic Tis (pTis) to pT2 than in those with pT3 tumors, the p value was close to 0.05 (p = 0.047). The tumor-surrounding mesorectum showed no significant differences in the aforementioned parameters between patients with positive MRI-detected extramural vascular invasion (mrEMVI) and those with negative mrEMVI. CONCLUSION. Mesorectum that surrounded rectal tumor had a higher blood flow than that close to the normal rectal wall. The blood flow decreased in the tumor-surrounding mesorectum when there was nodal involvement.

Stasis Leg Ulcers: Venous System Revises by Triggered Angiography Non-Contrast-Enhanced Sequence Magnetic Resonance Imaging.

Objectives: The distribution of venous pathology in stasis leg ulcers is unclear. The main reason for this uncertainty is the lack of objective diagnostic tools. To fill this gap, we assessed the effectiveness of triggered angiography non-contrast-enhanced (TRANCE)-magnetic resonance imaging (MRI) in determining the venous status of patients with stasis leg ulcers. Methods: This prospective observational study included the data of 23 patients with stasis leg ulcers who underwent TRANCE-MRI between April 2017 and May 2020; the data were retrospectively analyzed. TRANCE MRI utilizes differences in vascular signal intensity during the cardiac cycle for subsequent image subtraction, providing not only a venogram but also an arteriogram without the use of contrast agents or radiation. Results: TRANCE MRI revealed that the stasis leg ulcers of nine of the 23 patients could be attributed to valvular insufficiency and venous occlusion (including deep venous thrombosis [DVT], May–Thurner syndrome, and other external compression). Moreover, TRANCE MRI demonstrated no venous pathology in five patients (21.7%). We analyzed TRANCE MRI hemodynamic parameters, namely stroke volume, forward flow volume, backward flow volume, regurgitant fraction, absolute volume, mean flux, stroke distance, and mean velocity, in the external iliac vein, femoral vein, popliteal vein, and great saphenous vein (GSV) in three of the patients with valvular insufficiency and three of those with venous occlusion. We found that the mean velocity and stroke volume in the GSV was higher than that in the popliteal vein in all patients with venous valvular insufficiency. Conclusions: Stasis leg ulcers may have no underlying venous disease and could be confirmed by TRANCE-MRI. TRANCE MRI has good Interrater reliability between Duplex study in greater saphenous venous insufficiency. It also potentially surpasses existing diagnostic modalities in terms of distinguishable hemodynamic figures. Accordingly, TRANCE-MRI is a safe and useful tool for examining stasis leg ulcers and is extensively applied currently.

Prostatitis, the Great Mimicker of Prostate Cancer: Can We Differentiate Them Quantitatively With Multiparametric MRI?

OBJECTIVE. The purpose of this study was to investigate the diagnostic performance of semiquantitative and quantitative pharmacokinetic parameters and quantitative apparent diffusion coefficient (ADC) values obtained from prostate multiparametric MRI (mpMRI) to differentiate prostate cancer (PCa) and prostatitis objectively. MATERIALS AND METHODS. We conducted a retrospective review of patients with biopsy-proven PCa or prostatitis who underwent mpMRI study between January 2015 and February 2018. Mean ADC, forward volume transfer constant (Ktrans), reverse volume transfer constant (kep), plasma volume fraction (Vp), extravascular extracellular space volume fraction (Ve), and time to peak (TTP) values were calculated for both lesions and contralateral normal prostate tissue. Signal intensity-time curves were analyzed. Lesion-to-normal prostate tissue ratios of pharmacokinetic parameters were also calculated. The diagnostic accuracy and cutoff points of all parameters were analyzed to differentiate PCa from prostatitis. RESULTS. A total of 138 patients (94 with PCa and 44 with prostatitis) were included in the study. Statistically, ADC, quantitative pharmacokinetic parameters (Ktrans, kep, Ve, and Vp), their lesion-to-normal prostate tissue ratios, and TTP values successfully differentiated PCa and prostatitis. Surprisingly, we found that Ve values were significantly higher in prostatitis lesions. The combination of these parameters had 92.7% overall diagnostic accuracy. ADC, kep, and TTP made up the most successful combination for differential diagnosis. Analysis of the signal intensity-time curves showed mostly type 2 and type 3 enhancement curve patterns for patients with PCa. Type 3 curves were not seen in any prostatitis cases. CONCLUSION. Quantitative analysis of mpMRI differentiates PCa from prostatitis with high sensitivity and specificity, appears to have significant potential, and may improve diagnostic accuracy. In addition, evaluating these parameters does not cause any extra burden to the patients.

A Backward Zenneck Wave Propagating along a Plane Interface between Media

We consider a surface Zenneck wave that propagates along a plane interface between a vacuum and a medium that is described by an isotropic dielectric permittivity and a surface Zenneck wave that propagates along a plane interface between a vacuum and a medium that is described by isotropic dielectric permittivity and magnetic permeability. In the latter case, we also consider an H wave and the possibility that the real parts of the permittivity and permeability are negative. Forward and backward waves at the boundary of a material with inhomogeneous profiles of the dielectric permittivity and magnetic permeability are considered. The conditions of the existence of forward and backward surface and volume waves, as well as of fast and slow surface waves are investigated.

Reproducibility of geometric and flow-based echocardiographic measurements used for quantification of left ventricular total and forward stroke volume in healthy dogs

BackgroundCardiac structure and function in dogs are commonly assessed using echocardiography. A variety of linear, area, and flow-based measurements can be used to calculate left ventricular (LV) total stroke volume (TSV) and forward stroke volume (FSV), but the reproducibility of many of these measurements has not been fully studied. We hypothesized that survey of echocardiographic variables would identify those with high reproducibility and inform future investigation of different methods to measure LV TSV and FSV. MethodsThe reproducibility of 25 geometric and flow-based echocardiographic measurements was prospectively evaluated in 23 healthy dogs by two experienced observers. Reproducibility (i.e., interobserver agreement) was described using intraclass correlation coefficients. The reproducibility of various methods to calculate LV TSV and FSV was explored. ResultsReproducibility was generally good to excellent. Variables of LV width, length, and area and aortic and sinotubular junction diameter and velocity time integral were among measures with the highest reproducibility. Measurements of mitral annular diameter and mitral inflow velocity time integral possessed lower reproducibility. Calculation of LV TSV using measurements involved in the cube and bullet formulas demonstrated higher reproducibility than the Simpson's method of disks or mitral inflow methods. Calculation of LV FSV using LV outflow tract and aortic diameters from the right parasternal view generally demonstrated higher reproducibility compared with the left-sided view. ConclusionsThe reproducibility of many simple geometric and flow-based echocardiographic measurements is high. Comparison of the reliability of different measurement informs future investigation of echocardiographic methods to determine LV TSV and FSV in dogs.

Assessment of impact of daily huddles and visual displays on medication delivery timeliness in a large academic medical center.

To evaluate the impact of pharmacy team huddles and near real-time performance dashboards on the punctuality of medication delivery departures from the adult inpatient pharmacy of a multihospital medical center. Baseline delivery punctuality was established during a 2-week unannounced preintervention period, followed by the implementation of daily huddles focused on delivery timeliness along with visual displays of delivery performance metrics. The 5- to 15-minute huddles included pharmacy technicians, pharmacists, and managers. Printed visual displays that tracked hour-by-hour timeliness over the prior 24 hours were prominently displayed in the pharmacy. The primary outcome was the overall change in the percentage of punctual medication delivery departures (ie, deliveries leaving the pharmacy at the scheduled time) during the 2 weeks after implementation of huddles and visual displays (the postintervention period). Punctuality was assessed at both the day and shift levels using generalized estimating equations in a piecewise regression model. A multivariable model was constructed using a forward stepwise selection process to assess the potential impacts of workload drivers and staffing levels on medication delivery punctuality. During the pre- and postintervention periods, the punctuality of a total of 1,032 deliveries was recorded. Punctuality of deliveries across all shifts increased by 37% (95% confidence interval [CI], 18%-56% [P < 0.001]), from 50% to 87%, immediately following implementation of the huddle intervention. When punctuality was assessed by individual shift, we observed statistically significant increases for the day (35% [95% CI, 13%-57%], P = 0.002), evening (34% [95% CI, 12%-56%], P = 0.003) and night (57% [95% CI, 35%-79%], P < 0.001) shifts. During the forward stepwise multivariable model-building process, order volume, message volume, and technician staffing levels were not significantly correlated with delivery punctuality at the day or shift level. Daily huddles with visual displays were successful in improving the punctuality of medication delivery departures from the pharmacy, independent of workload drivers and staffing levels.

Is cerebral spinal fluid flow associated with body mass index and head circumference in healthy children? A phase contrast magnetic resonance imaging study

BackgroundThe aim of this study was to investigate the relationship between age, gender, body mass index (BMI), and head circumference (HC) and cerebral spinal fluid (CSF) flow dynamics in the pediatric population. The prospective study included a total of 137 participants, 75 boys and 62 girls, ranging in age from 2 to 204 months. Quantitative evaluation of CSF flow was made by using phase contrast magnetic resonance imaging (PC-MRI) in the axial plane at the level of the aqueductus cerebri. Flow dynamics were recorded as peak and mean velocity (cm/s); cranial, caudal, and net volume (ml); and aqueductus cerebri area (mm2). Correlation between baseline descriptive parameters, including age, gender, BMI, and HC, and the aforementioned CSF flow dynamics were investigated.ResultsThe net volume was significantly lower in girls (p = 0.002). There was no association between age and aqueduct area, mean velocity, and cranial volume. The peak velocity was remarkably higher in children (p = 0.03), whereas cranial and net volume were found to be lower in infants (p = 0.04 and p = 0.03, respectively). Notably, cases with HC below normal values had lower cranial, caudal, and net volume and aqueductus cerebri area (p = 0.01, p = 0.03, p = 0.03, and p = 0.04, respectively). There was no association between BMI and indicators of CSF flow dynamics in PC-MRI.ConclusionBMI and HC may be associated with CSF flow dynamics in children. A smaller HC is accompanied by a lower forward flow volume, reverse flow volume, net volume, and aqueductal diameter. These points should be remembered during the design of further trials on determinants of CSF flow in children.

Mode conversion characteristics of multimode magneto-optical Bragg diffraction cells

We study the dependence of magneto-optical (MO) coupling coefficients on the modal fields for the design of multi-mode MO Bragg cells. The mode conversion and diffraction efficiencies between the same order TM and TE modes can theoretically be up to about 98% by adjusting the excitation frequency of the fundamental-mode magneto-static forward volume wave (MSFVW) in the bismuth-substituted yttrium iron garnet film at the optimized thickness and length. The different order mode conversion is also available by means of the higher-mode MSFVWs. The resulting mode conversion-based switch function is discussed.