Washout Rate Research Articles

Strength evaluation of a new underwater concrete type

A comprehensive research study was conducted to evaluate the compressive strength of a new underwater concrete (UWC) type, commonly referred to as self-protected underwater concrete (SPUC). As the compressive strength is generally considered an essential characteristic of the performances of hydraulic and marine structures, especially because it is affected by the washout rate, the compressive strengths of SPUC were determined using the same concrete mixtures as those used for the SPUC washout loss tests. The concept of SPUC is different from that of the conventional UWC because it depends on the alteration of water characteristics in conjunction with the use of an underwater protective agent (UPA), such that the water medium can be readily available to receive fresh self-compacted concrete without mass loss. In addition to the air specimen, a strength test was conducted with freshwater and seawater specimens. The test results showed that the relative compressive strengths reached values equal to 90% and 88.48% for seawater and freshwater, respectively. These findings are compatible with the washout measurement outcomes. In addition, it is notable that the optimum slump flow for the compressive strength of the SPUC should not exceed 650 mm. Furthermore, the 28-day strength can be inferred from the 7-day strengths of freshwater and seawater.

Quantitative evaluation of simultaneous spatial and temporal regularization in dynamic contrast-enhanced MRI of the liver using Gd-EOB-DTPA

The purpose of this study was to quantitatively evaluate the usefulness of simultaneous spatial and temporal regularization using total variation (TV), total generalized variation (TGV), a combination of low-rank decomposition (LRD) and TV (LRD+TV), a combination of LRD and TGV (LRD+TGV), and nuclear norm (NN) when applied to dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in rats with concanavalin A (ConA)-induced acute hepatic injury.The rats were divided into three groups: normal control (NC) (n = 10), ConA10 (n = 8), and ConA20 (n = 7). Rats in the ConA10 and ConA20 groups were intravenously injected with 10 and 20 mg/kg of ConA, respectively; those in the NC group were intravenously injected with the same volume of saline. DCE-MRI studies were performed using gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA; 0.025 mmol Gd/kg) as a contrast agent (CA), 24 h after the ConA or saline injection. After the DCE-MRI study, we generated zero-filled and undersampled k-space data from the original images using a pseudoradial sampling scheme with 4 to 64 spokes. We subsequently reconstructed images from these data using the above regularizers and calculated the signal-to-error ratio (SERimg) and structural similarity index measure (SSIM) using the original and reconstructed images. We also calculated the area under the curve (AUC), rate of CA washout (λw), maximum relative enhancement (REmax), and time to REmax (Tmax) from time-intensity curves using an empirical mathematical model (EMM) and the signal-to-error ratio for curve fitting (SERfit) from the original and fit curves. We also compared the parameters obtained using the pseudoradial and Cartesian sampling schemes in the NC group.When using LRD+TV and LRD+TGV, both SERimg and SSIM were greater than those for the other regularizers at all spoke numbers studied; the SERfit for TGV was the greatest. When using TGV and LRD+TGV, in the majority of cases the AUCs did not significantly differ from those obtained from the original images, whereas those for LRD+TV and NN were significantly less at several spoke numbers. The λw for NN was significantly greater at numerous spoke numbers in the NC group; the REmax values for LRD+TV and NN were significantly less at several spoke numbers in all groups. The Tmax values for TV, TGV, and LRD+TGV were significantly greater at numerous spoke numbers in the NC group. Although there were significant differences in SERimg and SSIM between the pseudoradial and Cartesian sampling schemes, the kinetic parameters obtained by the EMM did not significantly differ between the two sampling schemes, with certain exceptions.In conclusion, our results suggest that simultaneous spatial and temporal regularization using TGV or LRD+TGV is useful for accelerating DCE-MRI without significant reduction in the accuracy of the kinetic parameter estimation, even at extremely low sampling factors.

Modified Algorithm Using Total Count for Calculating Myocardial Washout Rate in Single-Photon Emission Computerized Tomography.

Background: The arithmetic mean of washout rate (WR) (namely, AMWR) of each segment is a commonly used algorithm for calculating WR from a polar map in single-photon emission computerized tomography (SPECT). However, in this algorithm, uneven radiotracer uptake among segments affects WR calculation. To solve this possible issue, we formulated a modified algorithm for calculating WR based on the total count (namely, TCWR). Methods: The WR of iodine-123-β-methyl-p-iodophenylpentadecanoic acid (BMIPP) was calculated using TCWR and AMWR, and WR values using TCWR and AMWR were compared by disease. Participants included those without cardiovascular diseases (normal), those with CD36 deficiency, triglyceride deposit cardiomyovasculopathy (TGCV), TGCV with old myocardial infarction (OMI), and non-TGCV with OMI. Results: WR values using TCWR and AMWR did not differ significantly in the following groups: normal, 27.4±8.5 and 27.3±8.5% (p=0.97); CD36 deficiency, -3.2±6.5 and -4.1±7.4% (p=0.81); TGCV, 2.4±6.3 and 2.2±6.3% (p=0.93); and TGCV with OMI, -0.9±7.6 and -3.7±8.4% (p=0.32). However, AMWR showed a lower WR than TCWR in non-TGCV with OMI (4.8±8.7 and 18.9±6.7%, p=0.0008). Conclusions: TCWR is suitable for calculating WR using SPECT polar maps even in cases with heterogeneous radiotracer uptake, such as OMIs. TCWR may be applied to measuring the WR of radiopharmaceuticals other than BMIPP in investigating the pathophysiology of heart diseases.

123I-BMIPP Scintigraphy Shows That CNT-01 (Tricaprin) Improves Myocardial Lipolysis in Patients with Idiopathic Triglyceride Deposit Cardiomyovasculopathy: First Randomized Controlled, Exploratory Trial for TGCV.

Background: Triglyceride deposit cardiomyovasculopathy (TGCV) is a rare intractable cardiovascular disorder (Orphanet ORPHAcode: 565612) in which defective intracellular lipolysis results in heart failure and coronary artery disease. Myocardial scintigraphy with 123I-β-methyl-p-iodophenylpentadecanoic acid (BMIPP) is useful to evaluate myocardial TG metabolism; its washout rate (WR) reflects myocardial lipolysis. This study reports the effects of CNT-01 (tricaprin), a developing orphan drug to facilitate lipolysis, on BMIPP-WR in patients with TGCV. Methods: An investigator-initiated, multicenter, randomized, double-blind exploratory, trial (Phase IIa) was conducted (UMIN000035403). Seventeen patients with idiopathic TGCV were orally administered 1.5 g/day of CNT-01 or placebo for 8 weeks. Endpoints included delta BMIPP-WR and clinical parameters such as 6-minwalk distance and TGCV severity score. Results: During the protocol, delta BMIPP-WRs were -0.26±3.28 and 7.08±3.28% (95% confidence intervals, -7.36 to 6.84 and -0.01 to 14.18) in the placebo and CNT-01 groups, respectively. The baseline-adjusted difference of delta BMIPP-WR between the two groups was significant (p=0.035) after one patient was excluded from the placebo group because of pseudonormalization of BMIPP-WR related to coronary bypass graft stenosis. Clinical parameters did not show significant changes. Conclusions: This study proved the mechanism of CNT-01 to improve myocardial lipolysis in TGCV, as demonstrated by BMIPP scintigraphy.

Surgical Treatment for Septic Ankle Arthritis: A Comparison of Arthrotomy and Arthroscopy

Category:Ankle; ArthroscopyIntroduction/Purpose:Ankle joint septic arthritis can result in substantial morbidity involving cartilage destruction, bone erosion, osteomyelitis and loss of function. Operative intervention is the preferred method of irrigation and debridement, and options include both open arthrotomy and arthroscopic debridement. Prior studies have established both ankle arthroscopy and arthrotomy as effective management strategies for the treatment of ankle septic arthritis. However, no prior research has compared open arthrotomy verses arthroscopy to treat septic arthritis of the ankle, and it is unclear if one approach is superior to the other. The purpose of this study is to compare the rate of reoperation and 90-day perioperative complications between arthroscopy and open arthrotomy for the treatment of septic ankle arthritis using a national all-payer claims database.Methods:Patients who were diagnosed with septic arthritis in a native ankle and underwent irrigation and debridement through arthroscopy or arthrotomy were identified in the 2010-2019 PearlDiver database using International classification of diseases (ICD) and current procedural (CPT) codes. Demographic characteristics including age, gender and Elixhauser comorbidities were obtained for each cohort. The rate of reoperation, defined as a proxy for failure of initial intervention, was the primary outcome. Secondary outcomes including readmission, surgical site infection (SSI) and other 90-day complications were compared between the two cohorts. Univariate analysis using chi-square tests and student T-tests were performed to analyze any differences in patient demographics, comorbidities and complications. Multivariate analysis through logistic regression was subsequently conducted to account for any confounding variables and covariates.Results:In total, 331 patients undergoing arthroscopy and 886 patients undergoing arthrotomy for septic ankle arthritis were identified. On univariate analysis, the incidence of reoperation was higher in the open arthrotomy cohort (12.30%) compared to the arthroscopy cohort (9.37%), however this result was not statistically significant (p=.153). There was also no statistically significant difference between the two cohorts in superficial SSI incidence (3.95% vs. 2.42%, p=.197), readmission rates (36.79% vs. 34.14%, p=.0.391). However, the incidence of renal failure was higher in the open arthrotomy cohort (17.83%) compared with the arthroscopy cohort (12.39%) (p=.022). On multivariate analysis, the incidence of reoperation was higher for those undergoing ankle arthrotomy (OR 1.421; 95% CI 0.937-2.255; p=.108) relative to arthroscopy, however this result was not statistically significant (Table 1). The incidence of renal failure was higher in the open arthrotomy cohort after multivariate analysis (OR 1.615; 95% CI 1.113-2.393; p=0.014).Conclusion:This study demonstrated similar 90-day rates of reoperation, postoperative complications and readmissions, suggesting that arthrotomy and arthroscopy have similar efficacy in treating septic ankle arthritis. Although renal failure was more prevalent in the cohort undergoing open arthrotomy, differences in the primary endpoint of reoperation/repeat washout rates were non-significant. Based on these findings, deciding between these two operative approaches may be determined by patient specific risk factors and factors not elicited by this study including surgeon comfort with the technique, rather than the treatment modality itself.

Myocardial innervation imaging: MIBG in clinical practice

Abstract 123I-metaiodobenzylguanidine (MIBG) is a radiolabeled norepinephrine analog that can be used to investigate myocardial sympathetic innervation. 123I MIBG scintigraphy has been investigated with interest in many disease settings. In patients with systolic heart failure (HF), 123I MIBG scintigraphy can capture functional impairment and rarefaction of sympathetic terminals (which manifest as reduced early and late heart-to-mediastinum [H/M] ratio on planar scintigraphy), and increased sympathetic outflow (which can be visualized as high washout rate). These findings have been consistently associated with a worse outcome: most notably, a phase 3 trial found that patients with a late H/M 1.60 have a higher incidence of all-cause and cardiovascular mortality and life-threatening arrhythmias over a follow-up of less than 2 years. Despite these promising findings, 123I MIBG scintigraphy has not yet been recommended by major HF guidelines as a tool for additive risk stratification, and has then never entered the stage of widespread adoption into current clinical practice. 123I MIBG scintigraphy has been evaluated also in patients with myocardial infarction, genetic disorders characterized by an increased susceptibility to ventricular arrhythmias, and several other conditions characterized by impaired sympathetic myocardial innervation. In the present chapter we will summarize the state-of-the-art on cardiac 123I MIBG scintigraphy, the current unresolved issues, and the possible directions of future research.

594 Impact of admission hyperglycaemia on heart failure events and mortality in patients with Takotsubo syndrome at long-term follow-up: data from the high-Glucotako investigators

Abstract Aims As known, Takotsubo Syndrome (TTS) can occur during stressful events that result in sympathetic overactivity. No studies have investigated the sympathetic activity and long-term prognosis in patients with TTS and admission hyperglycaemia vs. normoglycaemia. Moreover, whether hyperglycaemia may serve as a metabolic trigger to unbalance the sympathetic system axis as well as through over-inflammation is not fully understood. To investigate admission hyperglycaemia effects on the sympathetic system and long-term prognosis in Takotsubo syndrome (TTS). Methods and results In this multicentre study, we screened 4783 patients undergoing coronary angiography within the first 72 h of hospitalization for suspected acute coronary syndrome between January 2015 and January 2018. All enrolled patients met the InterTAK diagnostic criteria proposed in the European Society of Cardiology position statement for the diagnosis of TTS. Exclusion criteria encompassed patients with previous myocardial infarction, TTS events, or chronic kidney or liver disease. Patients with TTS were divided into those with hyperglycaemia vs. those with normoglycaemia according to a cutoff admission blood glucose value of 140 mg/dl. Sympathetic activity was assayed by blood values of norepinephrine and 123I-labelled metaiodobenzylguanidine (MIBG) cardiac scintigraphy with late heart-to-mediastinum ratio (H/Mlate) and washout rate (WR), performed in 30 patients who did not present any contraindication to the examination, evaluated at baseline and at follow-up. Similarly, systemic inflammatory markers [C-reactive protein (CRP), white blood cell count (leukocytes and neutrophils), tumour necrosis factor-alpha (TNF-a)] and B-type natriuretic peptide (BNP) were assessed. Prespecified endpoints [heart failure (HF) and all-cause deaths] were assessed at long-term follow-up (12 and 24 months). At hospitalization, TTS patients with hyperglycaemia (N = 28) vs. those with normoglycaemia (M = 48) had significantly higher levels of inflammatory markers and B-type natriuretic peptide and lower left ventricular ejection fraction. Admission glucose values were correlated with norepinephrine levels (R2 = 0.39; P = 0.001). In 30 patients with TTS, 123I-MIBG cardiac scintigraphy showed lower late heart-to-mediastinum ratio values in the acute phase (P < 0.001) and at follow-up (P < 0.001) in those with hyperglycaemia. Patients with hyperglycaemia had higher rates of HF (P < 0.001) and death events (P < 0.05) after 24 months. In multivariate Cox regression analysis, hyperglycaemia (P = 0.008), tumour necrosis factor-alpha (P = 0.001), and norepinephrine (P = 0.035) were independent predictors of HF events. Conclusions Patients with TTS and hyperglycaemia exhibit sympathetic overactivity with a hyperglycaemia-mediated proinflammatory pathway, which could determine a worse prognosis during follow-up.

Histogram analysis of dynamic contrast-enhanced magnetic resonance imaging in the differential diagnosis of parotid tumors

ObjectiveDynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) histograms were used to investigate whether their parameters can distinguish between benign and malignant parotid gland tumors and further differentiate tumor subgroups.Materials and methodsA total of 117 patients (32 malignant and 85 benign) who had undergone DCE-MRI for pretreatment evaluation were retrospectively included. Histogram parameters including mean, median, entropy, skewness, kurtosis and 10th, 90th percentiles were calculated from time to peak (TTP) (s), wash in rate (WIR) (l/s), wash out rate (WOR) (l/s), and maximum relative enhancement (MRE) (%) mono-exponential models. The Mann–Whitney U test was used to compare the differences between the benign and malignant groups. The diagnostic value of each significant parameter was determined on Receiver operating characteristic (ROC) analysis. Multivariate stepwise logistic regression analysis was used to identify the independent predictors of the different tumor groups.ResultsFor both the benign and malignant groups and the comparisons among the subgroups, the parameters of TTP and MRE showed better performance among the various parameters. WOR can be used as an indicator to distinguish Warthin’s tumors from other tumors. Warthin’s tumors showed significantly lower values on 10th MRE and significantly higher values on skewness TTP and 10th WOR, and the combination of 10th MRE, skewness TTP and 10th WOR showed optimal diagnostic performance (AUC, 0.971) and provided 93.12% sensitivity and 96.70% specificity. After Warthin’s tumors were removed from among the benign tumors, malignant parotid tumors showed significantly lower values on the 10th TTP (AUC, 0.847; sensitivity 90.62%; specificity 69.09%; P < 0.05) and higher values on skewness MRE (AUC, 0.777; sensitivity 71.87%; specificity 76.36%; P < 0.05).ConclusionDCE-MRI histogram parameters, especially TTP and MRE parameters, show promise as effective indicators for identifying and classifying parotid tumors. Entropy TTP and kurtosis MRE were found to be independent differentiating variables for malignant parotid gland tumors. The 10th WOR can be used as an indicator to distinguish Warthin’s tumors from other tumors.

Influence of characteristics of epicardial adipose tissue and myocardial sympathetic innervation on the development of late recurrence of atrial fibrillation after radiofrequency ablation

Aim. To investigate the relationship between radiological characteristics of epicardial adipose tissue (EAT) and myocardial sympathetic activity, as well as to study their association with late recurrence of atrial fibrillation (AF) after radiofrequency ablation (RFA).Material and methods. This prospective study included 26 people with persistent and long-standing persistent AF scheduled for interventional AF treatment. Before the RFA procedure, all patients underwent cardiac 123I-metaiodobenzylguanidine (123I-MIBG) scintigraphy to assess the myocardial sympathetic innervation and contrast-enhanced cardiac multislice computed tomography to assess pulmonary vein anatomy, left atrial volume, and EAT volume. Clinical follow-up, including 12-lead electrocardiography (ECG) and 24-hour ECG monitoring, was carried out 3, 6 and 12 months after RFA.Results. After the end of follow-up, the patients were divided into two groups: with AF recurrence (group 1, n=8) and without AF recurrence (group 2, n=18). Multivariate logistic analysis found that only the 123I-MIBG washout rate (odds ratio, 1,0943; 95% confidence interval, 1,0138-1,1812) proved to be an independent predictor of late AF recurrence after RFA. ROC analysis revealed that a 123I-MIBG washout rate &gt;21% with a sensitivity of 75% and a specificity of 83,3% (AUC=0,844; p&lt;0,001) predicts late AF recurrence after RFA.Conclusion. Parameters of myocardial sympathetic activity, assessed by 123I-MIBG myocardial scintigraphy, are associated with late AF recurrence after RFA in patients with persistent and long-standing persistent AF. There were no reliable data confirming associations between myocardial sympathetic innervation and radiological EAT indicators, as well as the effect of the latter on the risk of AF recurrence after RFA.

Abstract 9397: Sonothrombolysis Improves Cardiac Segmental Contractility, Myocardial Perfusion and Baroreflex Gain in Patients With ST-segment Elevation Myocardial Infarction (stemi) in Long-Term Follow-Up

Sonothrombolysis (Sono) has improved microvascular obstruction, global contractility and infarct area after STEMI. Objective: To evaluate the long-term effect of Sono and its physiologic mechanisms in a subgroup of 51 STEMI patients (percutaneous coronary intervention-PCI (N=24) and PCI+Sono (N=27)) from previous randomized study. All patient were treated with PCI and those also treated with Sono received frequent image-guided diagnostic high mechanic index impulses applied to the myocardial contrast-enhanced areas (microbubbles) in the apical views (1.8 MHz; 1.1 to 1.3 MI; &lt;5-μ pulse duration). Evaluations were at pre-treatment, 1 month (ultrasound-US with contrast agent) and at averaged 34±17 months after STEMI (US with contrast agent; cardiac and peripheral sympathetic activity by means of 123 I-MIBG cardiac scintigraphy and microneurography; baroreflex gain of heart rate (HR) control by means of transfer function analysis). (For significance: P level ≤ 0.05). US values are on table. Adding, PCI+Sono showed lower left ventricular end-diastolic volume (LVEDV) remodelling (22±36 vs. 44±42%, P&lt;0.05). Cardiac scintigraphy showed similar late Heart/Mediastinum ratio and similar washout rate between groups. Muscle sympathetic nervous activity was also similar in both groups. PCI+Sono showed higher baroreflex gain of HR control (8±3 vs. 6±2 ms/mmHg, P=0.05), indicating an improved baroreflex sensitivity. In addition, perfusion score index correlated positively with wall motion score index (r=0.97, P&lt;0.001) and washout rate (r=0.30, P=0.04). LV ejection fraction correlated negatively with wall motion score index (r=-0.53), perfusion score index (r=-0.48) and LVEDV (r=-0.29) (P&lt;0.05). In conclusion, Sono added to PCI improved contractility and myocardial perfusion in STEMI. Despite high level of sympathetic activity, baroreflex gain of HR was ameliorated in PCI+Sono patients, probably due to better myocardial perfusion and lower LV remodelling.

Factors Influencing Cardiac Sympathetic Nervous Function in Patients With Severe Aortic Stenosis: Assessment by 123I-Metaiodobenzylguanidine Myocardial Scintigraphy

Numerous studies have shown that 123I-metaiodobenzylguanidine (MIBG) scintigraphy, an index of cardiac sympathetic nervous (CSN) activity, is useful for predicting prognosis in patients with heart failure. However, the factors influencing the CSN activity of patients with severe aortic stenosis (AS) remain unclear. We enrolled 91 patients with severe AS who underwent 123I-MIBG scintigraphy, coronary computed tomography (CCT), and transthoracic echocardiography. When CCT angiography (CCTA) showed an obstructive epicardial artery, invasive coronary angiography was performed within 1 week of CCTA. There were 21 male and 70 female patients with a mean age of 84±5 years. Eighty-five (85) patients (93%) had hypertension and 13 patients (14%) had diabetes. Two (2) patients (2%) had previous myocardial infarction and eight (9%) had a previous coronary intervention. All patients had severe AS: aortic valve area was 0.63±0.18 cm2 and the mean pressure gradient was 56±19 mmHg. Regarding 123I-MIBG parameters, early heart-to-mediastinum (H/M) ratio was 3.1±0.5, delayed H/M ratio was 2.8±0.6, and the washout rate (WR) was 35%±13%. Multivariable linear regression analysis showed that coronary artery disease (β=-0.30, p=0.002) was an independent predictor of delayed H/M ratio, and that aortic valve area (β=-0.20, p=0.048) was an independent predictor of WR. Our findings suggest that coronary artery disease is an independent predictor of delayed H/M ratio, and aortic valve area is an independent predictor of WR in patients with severe AS.

Quantitative transport mapping (QTM) for differentiating benign and malignant breast lesion: Comparison with traditional kinetics modeling and semi-quantitative enhancement curve characteristics.

PurposeTo test the feasibility of using quantitative transport mapping (QTM) method, which is based on the inversion of transport equation using spatial deconvolution without any arterial input function, for automatically postprocessing dynamic contrast enhanced MRI (DCE-MRI) to differentiate malignant and benign breast tumors. Materials and methodsBreast DCE-MRI data with biopsy confirmed malignant (n = 13) and benign tumors (n = 13) was used to assess QTM velocity (|u|) and diffusion coefficient (D), volume transfer constant (Ktrans), volume fraction of extravascular extracellular space (Ve) from kinetics method, and traditional enhancement curve characteristics (ECC: amplitude A, wash-in rate α, wash-out rate β). A Mann-Whitney U test and receiver operating characteristic curve (ROC) analysis were performed to assess the diagnostic performance of these parameters for distinguishing between benign and malignant tumors. ResultsBetween malignant and benign tumors, there was a significant difference in |u| and Ktrans, (p = 0.0066, 0.0274, respectively), but not in D, Ve, A, α and β (p = 0.1119, 0.2382, 0.4418,0.2592 and 0.9591, respectively). ROC area-under-the-curve was 0.82, 0.75 (95% confidence level 0.60–0.95, 0.51–0.90) for |u| and Ktrans, respectively. ConclusionQTM postprocesses DCE-MRI automatically through deconvolution in space and time to solve the inverse problem of the transport equation. Comparing with traditional kinetics method and ECC, QTM method showed better diagnostic accuracy in differentiating benign from malignant breast tumors in this study.

Applicability of Narrow Groove Theory in Designing Washout Features for Rotary Blood Pumps.

High and low shear regions in rotary blood pumps require sufficient washout flow to minimize blood residence time, thereby preventing hemolysis or regions of stasis that can lead to pump thrombosis. Spiral groove bearings (SGBs) both enhance pump washout and reduce erythrocyte exposure to high shear. Narrow groove theory (NGT) has been used as an analytical tool to estimate the flow performance of a flat SGB during the design stage. However, NGT cannot accurately predict the performance of a conical SGB. In this study, we formulated an analytical model from the established NGT by adding an inertia correction term to incorporate variations in centrifugal force, which improved washout prediction in a conical SGB. The modified NGT model was then validated by comparison with experimental results. The results show that the modified NFT analytical model can reasonably predict washout rate when the spiral groove geometry favors creep flow conditions. The conical half angle of the SGB had the most significant impact on washout, with a decrease in half angle leading to large increases in wash-out flow. Small half angles also maintained viscous pumping at larger Reynolds numbers. In summary, the modified NGT can be a useful tool for designing conical SGBs for rotary blood pump washout within the creep flow regime.

Convolutional neural network-based automatic heart segmentation and quantitation in 123I-metaiodobenzylguanidine SPECT imaging

BackgroundSince three-dimensional segmentation of cardiac region in 123I-metaiodobenzylguanidine (MIBG) study has not been established, this study aimed to achieve organ segmentation using a convolutional neural network (CNN) with 123I-MIBG single photon emission computed tomography (SPECT) imaging, to calculate heart counts and washout rates (WR) automatically and to compare with conventional quantitation based on planar imaging.MethodsWe assessed 48 patients (aged 68.4 ± 11.7 years) with heart and neurological diseases, including chronic heart failure, dementia with Lewy bodies, and Parkinson's disease. All patients were assessed by early and late 123I-MIBG planar and SPECT imaging. The CNN was initially trained to individually segment the lungs and liver on early and late SPECT images. The segmentation masks were aligned, and then, the CNN was trained to directly segment the heart, and all models were evaluated using fourfold cross-validation. The CNN-based average heart counts and WR were calculated and compared with those determined using planar parameters. The CNN-based SPECT and conventional planar heart counts were corrected by physical time decay, injected dose of 123I-MIBG, and body weight. We also divided WR into normal and abnormal groups from linear regression lines determined by the relationship between planar WR and CNN-based WR and then analyzed agreement between them.ResultsThe CNN segmented the cardiac region in patients with normal and reduced uptake. The CNN-based SPECT heart counts significantly correlated with conventional planar heart counts with and without background correction and a planar heart-to-mediastinum ratio (R2 = 0.862, 0.827, and 0.729, p < 0.0001, respectively). The CNN-based and planar WRs also correlated with and without background correction and WR based on heart-to-mediastinum ratios of R2 = 0.584, 0.568 and 0.507, respectively (p < 0.0001). Contingency table findings of high and low WR (cutoffs: 34% and 30% for planar and SPECT studies, respectively) showed 87.2% agreement between CNN-based and planar methods.ConclusionsThe CNN could create segmentation from SPECT images, and average heart counts and WR were reliably calculated three-dimensionally, which might be a novel approach to quantifying SPECT images of innervation.

Endovascular renal sympathetic denervation to improve heart failure with reduced ejection fraction: the IMPROVE-HF-I study.

IntroductionThe aim of the present study was to assess the safety and efficacy of renal sympathetic denervation (RDN) in patients with heart failure with reduced ejection fraction (HFrEF).MethodsWe randomly assigned 50 patients with a left ventricular ejection fraction (LVEF) ≤ 35% and NYHA class ≥ II, in a 1:1 ratio, to either RDN and optimal medical therapy (OMT) or OMT alone. The primary safety endpoint was the occurrence of a combined endpoint of cardiovascular death, rehospitalisation for heart failure, and acute kidney injury at 6 months. The primary efficacy endpoint was the change in iodine-123 meta-iodobenzylguanidine (123I‑MIBG) heart-to-mediastinum ratio (HMR) at 6 months.ResultsMean age was 60 ± 9 years, 86% was male and mean LVEF was 33 ± 8%. At 6 months, the primary safety endpoint occurred in 8.3% vs 8.0% in the RDN and OMT groups, respectively (p = 0.97). At 6 months, the mean change in late HMR was −0.02 (95% CI: −0.08 to 0.12) in the RDN group, versus −0.02 (95% CI: −0.09 to 0.12) in the OMT group (p = 0.95) whereas the mean change in washout rate was 2.34 (95% CI: −6.35 to 1.67) in the RDN group versus −2.59 (95% CI: −1.61 to 6.79) in the OMT group (p-value 0.09).ConclusionRDN with the Vessix system in patients with HFrEF was safe, but did not result in significant changes in cardiac sympathetic nerve activity at 6 months as measured using 123I‑MIBG.Supplementary InformationThe online version of this article (10.1007/s12471-021-01633-z) contains supplementary material, which is available to authorized users.

Preparation and Characterization of Moldable Demineralized Bone Matrix/Calcium Sulfate Composite Bone Graft Materials.

Demineralized bone matrix (DBM) is a decalcified allo/xenograft retaining collagen and noncollagenous proteins, which has been extensively used because of its osteoconductive and osteoinductive properties. Calcium sulfate (CaSO4, CS) is a synthetic bone substitute used in bone healing with biocompatible, nontoxic, bioabsorbable, osteoconductive, and good mechanical characteristics. This study aims to prepare a DBM/CS composite bone graft material in a moldable putty form without compromising the peculiar properties of DBM and CS. For this purpose, firstly, porcine femur was defatted using chloroform/methanol and extracted by acid for demineralization, then freeze-dried and milled/sieved to obtain DBM powder. Secondly, the α-form and β-form of calcium sulfate hemihydrate (CaSO4·0.5H2O, CSH) were produced by heating gypsum (CaSO4·2H2O). The morphology and particle sizes of α- and β-CSH were obtained by SEM, and their chemical properties were confirmed by EDS, FTIR and XRD. Furthermore, the DBM-based graft was mixed with α- or β-CSH at a ratio of 9:1, and glycerol/4% HPMC was added as a carrier to produce a putty. DBM/CSH putty possesses a low washout rate, good mechanical strength and biocompatibility. In conclusion, we believe that the moldable DBM/CSH composite putty developed in this study could be a promising substitute for the currently available bone grafts, and might have practical application in the orthopedics field as a potential bone void filler.

Development and Evaluation of a Threshold-Based Motion Cueing Algorithm

In this paper, a motion cueing algorithm (MCA) without a frequency divider is proposed, which aims to reproduce the longitudinal reference acceleration as far as possible via tilt coordination. Using a second-order rate limit, the human perception thresholds can directly be taken into account when parameterizing the MCA. The washout is compensated by tilt coordination and means of feedback from the translational acceleration. The proposed MCA is compared with the classical washout algorithm and the compensation MCA based on selected qualitative metrics and their workspace demand. In addition, a subjective study on the evaluation of the MCA was conducted. The results show that even high washout rates are not noticeable by the test subjects. Overall, the MCA was rated as very good.

ACCELERATED TRACER WASHOUT IN REGIONS OF SYMPATHETIC DENERVATION IN HEART FAILURE PATIENTS WITH ISCHEMIC CARDIOMYOPATHY USING FLUBROBENGUANE POSITRON EMISSION TOMOGRAPHY IMAGING

<h3>BACKGROUND</h3> Sympathetic denervation has been shown to predict the risk of sudden cardiac death in ischemic cardiomyopathy (ICM) heart failure patients with implanted cardiac defibrillators. The previous PAREPET trial (JACC 2014;63(2):141) used the PET tracer hydroxyephedrine (HED) which is a false neurotransmitter analog of norepinephrine. This established tracer is labeled with the short-lived isotope C-11, which limits its widespread utility for risk stratification in clinical practice. The purpose of this study was to evaluate the ability of a new F-18-labeled PET tracer LMI-1195 (flubrobenguane) to measure regional denervation (tracer uptake) as well as sympathetic tone (washout rate) in ICM patients with heart failure. <h3>METHODS AND RESULTS</h3> A subset of patients (N=7) in the LMI-1195 vs HED validation trial underwent early (30 min) and late (4 hours) PET-CT imaging following injection of 3 MBq/kg of flubrobenguane. Five subjects were ICM patients and 2 were healthy normal controls. Regional tracer distribution was quantified on the early and late uptake images using the clinical 4DM-PET analysis program (Ann Arbor, MI). Percent washout rate was measured as (early-late) / early uptake (x100%) using a 9-segment model of left ventricle. In normal controls, there was minimal washout over the 4-hour interval between early and late images (4 +/- 4%). Tracer washout was significantly accelerated (P < 0.0001) in both ischemic regions and in remote (perfused) regions in the ICM patients (21 +/- 10% and 17% +/- 9% respectively), suggesting increased sympathetic tone in the whole-LV of these heart failure patients, with regionally higher tone in the ischemic zone. <h3>CONCLUSION</h3> Initial pilot studies evaluating the novel PET tracer [18F]flubrobenguane as a marker of presynaptic neuronal function in humans with and without HF was performed, showing accelerated washout in regions of sympathetic denervation in patients with ischemic cardiomyopathy. If confirmed in larger studies, this would represent a novel and non-invasive method to quantify cardiac sympathetic activity in-vivo. This new imaging method may be helpful in the future to identify cardiac regions associated with elevated arrhythmogenic risk.

Renal function and cardiac adrenergic impairment in patients affected by heart failure

Although in heart failure (HF) there is a strict correlation between heart and kidney, no data are available on the potential relationship in HF between renal dysfunction (RD) and the impaired sympathetic innervation. Aim of the present study was to assess the relationship between RD and cardiac sympathetic innervation in HF patients with reduced ejection fraction. Two hundred and sixty-three patients with mild-to-severe HF underwent iodine-123 meta-iodobenzylguanidine myocardial scintigraphy to assess sympathetic innervation, evaluating early and late heart-to-mediastinum (H/M) ratios and washout rate. In all patients, glomerular filtration rate (eGFR) by Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula was assessed. A direct association was found between EPI-eGFR and late H/M (r = .215; P < .001). Dividing the population into moderate-to-severe eGFR reduction and normal-to-mildly reduced eGFR (cutoff ≤ 60 mL·min−1·1.73 m−2), a statistically significant reduction of late H/M value was found in patients with RD compared to patients with preserved eGFR (P = .030). By multivariable linear regression analysis, eGFR resulted in the prediction of impaired late H/M in patients with RD (P = .005). Patients with RD and HF show more impaired cardiac sympathetic activity than HF patients with preserved renal function, and reduced eGFR is a predictor of reduced late H/M.

Efficiencies of anaerobic hybrid and UASB reactors to alleviate the adverse effect of elevated salinity in wastewater

AbstractBACKGROUNDUntreated high‐strength salinity wastewaters pose a serious threat to the environment. Anaerobic treatment is an effective process with double advantages of waste stabilization and energy production. However, high organic compound and sodium toxicity in high‐salinity wastewaters adversely affect the performance of anaerobic treatment. In this study, anaerobic hybrid (AH) and upflow anaerobic sludge blanket (UASB) reactors were investigated for their efficiencies to alleviate the negative effects of high‐salinity wastewater.RESULTSDouble increases in the NaCl concentration drastically deteriorated the performances of both reactors. The activities of acetoclastic methanogens (ACM) and hydrogenotrophic methanogens (HTM) in both reactors decreased to 22–28% and 36–40% compared to the previous period, respectively. However, the methanogen population (Methanosarcinales and Methanobacteriales) was not affected negatively. The AH reactor exhibited excellent performance during the recovery and restart periods, which only required 7 days to complete the recovery period. Furthermore, during the restart period, the AH reactor showed high chemical oxygen demand (COD) removal efficiency, methane (CH4) production and yield as ≈90%, 2600 mL day−1 and 0.30 m3 CH4 kg−1 CODremoved, respectively. The rate of biomass washout from the AH reactor also was lower compared to the UASB reactor. The concentration of attached biomass in the packed zone of the AH reactor gradually increased indicating the growth of an active microbial biofilm.CONCLUSIONThe excellent performance of the AH reactor was presumably a result of its packed zone configuration which provided the supporting media to entrap smaller microbial aggregates, reduce biomass washout and support the growth of active biofilm. © 2021 Society of Chemical Industry (SCI).