Flow Dynamic Analysis by Contrast-Enhanced Imaging Techniques of Medium Cutoff Membrane Hemodialyzer

Introduction: Medium cutoff (MCO) membranes represent an interesting innovation in the field of hemodialysis. Given the correlation between large (PM >25 kDa) middle molecules (LMM) and clinical outcomes, the possibility to broaden the spectrum of solutes removed in hemodialysis with MCO membranes introduces a new perspective for end-stage kidney disease patients. Due to low diffusion coefficients of LMM, the use of convection is required to maximize extracorporeal clearance. High convective rates are achieved with high-flux membranes in hemodiafiltration, a technique not available in the US. In case of the MCO membrane, remarkable clearances of LMM are achieved combining the permeability of the membrane with a significant amount of internal convection. The mechanism of filtration-backfiltration inside the dialyzer enables effective removal of LMM in a technique called expanded hemodialysis (HDx). Given such theoretical explanation, it is important to demonstrate the blood and ultrafiltration rheology inside the MCO dialyzer. Method: This study for the first time describes flow dynamic parameters and internal cross-filtration, thanks to specific radiology and nuclear imaging techniques. Results: Flow dynamic analysis of the blood and dialysate compartment confirms excellent distribution of velocities and an excellent matching of blood and dialysate. Average blood flow velocity allows for wall shear rates adequate to avoid protein stagnation at the blood membrane interface and increase in blood viscosity. Cross-filtration analysis demonstrates a remarkable filtration/backfiltration flux reaching values >30 mL/min at a blood flow of 300 mL/min and zero net filtration. Conclusion: The MCO dialyzer Theranova 400 appears to have a design optimized to perform expanded hemodialysis (HDx).

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Integration Between Computed Tomography and Nuclear Medicine for Non-invasive Assessment of Coronary Anatomy and Myocardial Perfusion

European Cardiology Review ◽

10.15420/ecr.2012.5.2.15 ◽

2009 ◽

Vol 5 (2) ◽

pp. 15

Author(s):

Wanda Acampa ◽

Mario Petretta ◽

Carmela Nappi ◽

Alberto Cuocolo ◽

◽

...

Keyword(s):

Computed Tomography ◽

Coronary Heart Disease ◽

Blood Flow ◽

Heart Disease ◽

Myocardial Perfusion ◽

Myocardial Blood Flow ◽

Imaging Techniques ◽

Emission Computed Tomography ◽

Coronary Anatomy ◽

Non Invasive

Many non-invasive imaging techniques are available for the evaluation of patients with known or suspected coronary heart disease. Among these, computed-tomography-based techniques allow the quantification of coronary atherosclerotic calcium and non-invasive imaging of coronary arteries, whereas nuclear cardiology is the most widely used non-invasive approach for the assessment of myocardial perfusion. The available single-photon-emission computed tomography flow agents are characterised by a cardiac uptake proportional to myocardial blood flow. In addition, different positron emission tomography tracers may be used for the quantitative measurement of myocardial blood flow and coronary flow reserve. Extensive research is being performed in the development of non-invasive coronary angiography and myocardial perfusion imaging using cardiac magnetic resonance. Finally, new multimodality imaging systems have recently been developed bringing together anatomical and functional information. This article provides a description of the available non-invasive imaging techniques in the assessment of coronary anatomy and myocardial perfusion in patients with known or suspected coronary heart disease.

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Cerebrovascular Blood Flow Dynamic Changes in Fetuses with Congenital Heart Disease

Fetal Diagnosis and Therapy ◽

10.1159/000209203 ◽

2009 ◽

Vol 25 (1) ◽

pp. 167-172 ◽

Cited By ~ 18

Author(s):

Lv Guorong ◽

Li Shaohui ◽

Jin Peng ◽

Lin Huitong ◽

Li Boyi ◽

...

Keyword(s):

Congenital Heart Disease ◽

Blood Flow ◽

Heart Disease ◽

Congenital Heart ◽

Flow Dynamic ◽

Dynamic Changes ◽

Blood Flow Dynamic

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Patient-specific computational haemodynamics associated with surgical creation of an arteriovenous fistula

10.21203/rs.3.rs-627689/v1 ◽

2021 ◽

Author(s):

George Hyde-Linaker ◽

Pauline Hall Barrientos ◽

Sokratis Stoumpos ◽

Asimina Kazakidi

Keyword(s):

Blood Flow ◽

Flow Rate ◽

Disease Patient ◽

Blood Flow Rate ◽

Fold Increase ◽

Transitional Flow ◽

Patient Specific ◽

Venous Anastomosis ◽

End Stage

Abstract Despite arteriovenous fistulae (AVF) being the preferred vascular access for haemodialysis, high primary failure rates (30-70%) and low one-year patency rates (40-70%) hamper their use. The haemodynamics within the vessels of the fistula change significantly following surgical creation of the anastomosis and can be a surrogate of AVF success or failure. Computational fluid dynamics (CFD) can crucially predict AVF outcomes through robust analysis of a fistula’s haemodynamic patterns, which is impractical in-vivo. We present a proof-of-concept CFD framework for characterising the AVF blood flow prior and following surgical creation of a successful left radiocephalic AVF in a 20-year-old end-stage kidney disease patient. The reconstructed vasculature was generated utilising multiple contrast-enhanced magnetic resonance imaging (MRI) datasets. Large eddy simulations were conducted for establishing the extent of arterial and venous remodelling. Following anastomosis creation, a significant 2-3-fold increase in blood flow rate was induced downstream of the left subclavian artery. This was validated through comparison with post-AVF patient-specific phase-contrast data. The increased flow rate yielded an increase in time-averaged wall shear stress (TAWSS), a key marker of adaptive vascular remodelling. We have demonstrated TAWSS and oscillatory shear distributions of the transitional-flow in the venous anastomosis are predictive of AVF remodelling.

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Nuclear Imaging in Infective Endocarditis

Pharmaceuticals ◽

10.3390/ph15010014 ◽

2021 ◽

Vol 15 (1) ◽

pp. 14

Author(s):

Nidaa Mikail ◽

Fabien Hyafil

Keyword(s):

Computed Tomography ◽

Infective Endocarditis ◽

Fdg Pet ◽

Imaging Techniques ◽

Nuclear Imaging ◽

Emission Tomography ◽

Cardiac Devices ◽

Pet Ct ◽

18F Fdg ◽

Fdg Pet Ct

Infective endocarditis (IE) is a life-threatening disease with stable prevalence despite prophylactic, diagnostic, and therapeutic advances. In parallel to the growing number of cardiac devices implanted, the number of patients developing IE on prosthetic valves and cardiac implanted electronic device (CIED) is increasing at a rapid pace. The diagnosis of IE is particularly challenging, and currently relies on the Duke-Li modified classification, which include clinical, microbiological, and imaging criteria. While echocardiography remains the first line imaging technique, especially in native valve endocarditis, the incremental value of two nuclear imaging techniques, 18F-fluorodeoxyglucose positron emission tomography with computed tomography (18F-FDG-PET/CT) and white blood cells single photon emission tomography with computed tomography (WBC-SPECT), has emerged for the management of prosthetic valve and CIED IE. In this review, we will summarize the procedures for image acquisition, discuss the role of 18F-FDG-PET/CT and WBC-SPECT imaging in different clinical situations of IE, and review the respective diagnostic performance of these nuclear imaging techniques and their integration into the diagnostic algorithm for patients with a suspicion of IE.

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Measurement of cerebrovascular reserve by multimodal imaging for cerebral arterial occlusion or stenosis patients: protocol of a prospective, randomized, controlled clinical study

Trials ◽

10.1186/s13063-019-3967-2 ◽

2020 ◽

Vol 21 (1) ◽

Author(s):

Zhi-peng Xiao ◽

ke Jin ◽

Jie-qing Wan ◽

Yong Lin ◽

Yao-hua Pan ◽

...

Keyword(s):

Clinical Trial ◽

Blood Flow ◽

Cerebral Blood Flow ◽

Ischemic Stroke ◽

Multimodal Imaging ◽

Imaging Techniques ◽

Trial Registry ◽

Clinical Trial Registry ◽

Cerebrovascular Reserve ◽

Randomized Controlled

Abstract Background Cerebrovascular reactivity (CVR) is the change in cerebral blood flow in response to a vaso-active stimulus, and may assist the treatment strategy of ischemic stroke. However, previous studies reported that a therapeutic strategy for stroke mainly depends on the degree of vascular stenosis with steady-state vascular parameters (e.g., cerebral blood flow and CVR). Hence, measurement of CVR by multimodal imaging techniques may improve the treatment of ischemic stroke. Methods/design This is a prospective, randomized, controlled clinical trial that aimed to examine the capability of multimodal imaging techniques for the evaluation of CVR to improve treatment of patients with ischemic stroke. A total of 66 eligible patients will be recruited from Renji Hospital, Shanghai Jiaotong University School of Medicine. The patients will be categorized based on CVR into two subgroups as follows: CVR > 10% group and CVR < 10% group. The patients will be randomly assigned to medical management, percutaneous transluminal angioplasty and stenting, and intracranial and extra-cranial bypass groups in a 1:1:1 ratio. The primary endpoint is all adverse events and ipsilateral stroke recurrence at 6, 12, and 24 months after management. The secondary outcomes include the CVR, the National Institute of Health stroke scale and the Modified Rankin Scale at 6, 12, and 24 months. Discussion Measurement of cerebrovascular reserve by multimodal image is recommended by most recent studies to guide the treatment of ischemic stroke, and thus its efficacy and evaluation accuracy need to be established in randomized controlled settings. This prospective, parallel, randomized, controlled registry study, together with other ongoing studies, should present more evidence for optimal individualized accurate treatment of ischemic stroke. Trial registration Chinese Clinical Trial Registry, ID: ChiCTR-IOR-16009635; Registered on 16 October 2016. All items are from the World Health Organization Trial Registration Data Set and registration in the Chinese Clinical Trial Registry: ChiCTR-IOR-16009635.

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Assessment of Right Ventricular Function: Role of Nuclear Imaging Techniques

Cardiology Clinics ◽

10.1016/s0733-8651(18)30253-4 ◽

1992 ◽

Vol 10 (1) ◽

pp. 23-39 ◽

Cited By ~ 15

Author(s):

Diwakar Jain ◽

Barry L. Zaret

Keyword(s):

Right Ventricular ◽

Ventricular Function ◽

Right Ventricular Function ◽

Imaging Techniques ◽

Nuclear Imaging

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From Mouse to Man and Back: Closing the Correlation Gap between Imaging and Histopathology for Lung Diseases

Diagnostics ◽

10.3390/diagnostics10090636 ◽

2020 ◽

Vol 10 (9) ◽

pp. 636 ◽

Cited By ~ 2

Author(s):

Birger Tielemans ◽

Kaat Dekoster ◽

Stijn E. Verleden ◽

Stefan Sawall ◽

Bartosz Leszczyński ◽

...

Keyword(s):

Lung Disease ◽

Disease Progression ◽

Lung Diseases ◽

Imaging Techniques ◽

Treatment Options ◽

Space Technology ◽

Study Results ◽

Life Threatening ◽

End Stage

Lung diseases such as fibrosis, asthma, cystic fibrosis, infection and cancer are life-threatening conditions that slowly deteriorate quality of life and for which our diagnostic power is high, but our knowledge on etiology and/or effective treatment options still contains important gaps. In the context of day-to-day practice, clinical and preclinical studies, clinicians and basic researchers team up and continuously strive to increase insights into lung disease progression, diagnostic and treatment options. To unravel disease processes and to test novel therapeutic approaches, investigators typically rely on end-stage procedures such as serum analysis, cyto-/chemokine profiles and selective tissue histology from animal models. These techniques are useful but provide only a snapshot of disease processes that are essentially dynamic in time and space. Technology allowing evaluation of live animals repeatedly is indispensable to gain a better insight into the dynamics of lung disease progression and treatment effects. Computed tomography (CT) is a clinical diagnostic imaging technique that can have enormous benefits in a research context too. Yet, the implementation of imaging techniques in laboratories lags behind. In this review we want to showcase the integrated approaches and novel developments in imaging, lung functional testing and pathological techniques that are used to assess, diagnose, quantify and treat lung disease and that may be employed in research on patients and animals. Imaging approaches result in often novel anatomical and functional biomarkers, resulting in many advantages, such as better insight in disease progression and a reduction in the numbers of animals necessary. We here showcase integrated assessment of lung disease with imaging and histopathological technologies, applied to the example of lung fibrosis. Better integration of clinical and preclinical imaging technologies with pathology will ultimately result in improved clinical translation of (therapy) study results.

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Nuclear Imaging Techniques for the Assessment of Myocardial Viability

Cardiology Clinics ◽

10.1016/s0733-8651(18)30061-4 ◽

1995 ◽

Vol 13 (1) ◽

pp. 43-57 ◽

Cited By ~ 11

Author(s):

Diwakar Jain ◽

Barry L. Zaret

Keyword(s):

Myocardial Viability ◽

Imaging Techniques ◽

Nuclear Imaging

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4D flow MRI for non-invasive measurement of blood flow in the brain: A systematic review

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x20952014 ◽

2020 ◽

pp. 0271678X2095201

Author(s):

Alasdair G Morgan ◽

Michael J Thrippleton ◽

Joanna M Wardlaw ◽

Ian Marshall

Keyword(s):

Blood Flow ◽

Imaging Techniques ◽

Acquisition Time ◽

4D Flow ◽

Non Invasive ◽

Major Vessel ◽

Dynamic Velocity ◽

Blood Flow Dynamics ◽

Cerebrovascular Imaging

The brain’s vasculature is essential for brain health and its dysfunction contributes to the onset and development of many dementias and neurological disorders. While numerous in vivo imaging techniques exist to investigate cerebral haemodynamics in humans, phase-contrast magnetic resonance imaging (MRI) has emerged as a reliable, non-invasive method of quantifying blood flow within intracranial vessels. In recent years, an advanced form of this method, known as 4D flow, has been developed and utilised in patient studies, where its ability to capture complex blood flow dynamics within any major vessel across the acquired volume has proved effective in collecting large amounts of information in a single scan. While extremely promising as a method of examining the vascular system’s role in brain-related diseases, the collection of 4D data can be time-consuming, meaning data quality has to be traded off against the acquisition time. Here, we review the available literature to examine 4D flow’s capabilities in assessing physiological and pathological features of the cerebrovascular system. Emerging techniques such as dynamic velocity-encoding and advanced undersampling methods, combined with increasingly high-field MRI scanners, are likely to bring 4D flow to the forefront of cerebrovascular imaging studies in the years to come.

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