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      • Non-invasive estimation of relative pressure in turbulent flow using virtual work-energy

        Marlevi, David,Ha, Hojin,Dillon-Murphy, Desmond,Fernandes, Joao F.,Fovargue, Daniel,Colarieti-Tosti, Massimiliano,Larsson, Matilda,Lamata, Pablo,Figueroa, C. Alberto,Ebbers, Tino,Nordsletten, David A. Elsevier 2020 Medical image analysis Vol.60 No.-

        <P><B>Abstract</B></P> <P>Vascular pressure differences are established risk markers for a number of cardiovascular diseases. Relative pressures are, however, often driven by turbulence-induced flow fluctuations, where conventional non-invasive methods may yield inaccurate results. Recently, we proposed a novel method for non-turbulent flows, <I>ν</I>WERP, utilizing the concept of virtual work-energy to accurately probe relative pressure through complex branching vasculature. Here, we present an extension of this approach for turbulent flows: <I>ν</I>WERP-t. We present a theoretical method derivation based on flow covariance, quantifying the impact of flow fluctuations on relative pressure. <I>ν</I>WERP-t is tested on a set of <I>in-vitro</I> stenotic flow phantoms with data acquired by 4D flow MRI with six-directional flow encoding, as well as on a patient-specific <I>in-silico</I> model of an acute aortic dissection. Over all tests <I>ν</I>WERP-t shows improved accuracy over alternative energy-based approaches, with excellent recovery of estimated relative pressures. In particular, the use of a guaranteed divergence-free virtual field improves accuracy in cases where turbulent flows skew the apparent divergence of the acquired field. With the original <I>ν</I>WERP allowing for assessment of relative pressure into previously inaccessible vasculatures, the extended <I>ν</I>WERP-t further enlarges the method's clinical scope, underlining its potential as a novel tool for assessing relative pressure <I>in-vivo</I>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> vWERP-t uses virtual work-energy to accurately assess turbulent relative pressure. </LI> <LI> In-vitro, vWERP-t shows 1:1 agreement with invasive measurements of relative pressure. </LI> <LI> In transient flow, vWERP-t shows significant improvement compared to other approaches. </LI> <LI> vWERP-t guarantees divergence free flow even in turbulent fields, improving accuracy. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

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        Impact of Airway Virus in Severe Asthmatic Patients: A Pilot Study

        Walsh Laura J,Sullivan Ashley,Ward Christopher,Fanning Liam J,O’Byrne Paul M,MacSharry John A,Murphy Desmond M 대한천식알레르기학회 2023 Allergy, Asthma & Immunology Research Vol.15 No.3

        The lungs have their own microbiota which seems to be altered in disease processes such as asthma. Viral infection accounts for many asthma exacerbations. Little is known about the lung virome, and the role that viruses play in non-exacerbating asthmatics. We aimed to assess if detection of virus in bronchoscopy samples of asthmatic patients in a non-exacerbating state influences their asthma control and modulates airway cytokine composition. Patients were recruited from a specialist asthma clinic and underwent bronchoscopy with standardised bronchoalveolar lavage (BAL). Viral analysis was performed; cell differential and cytokine levels were measured. Forty-six samples were obtained of which 10.8% demonstrated evidence of airway virus, and 91.3% of patients in the cohort were classed as severe asthmatics. Oral steroid use was significantly higher in severe asthmatic patients with virus detected, and the forced expiratory volume in one second tended to be lower in the virus-detected group. It was also found that BAL interleukin-13 and tumor necrosis factor-α levels were significantly higher in severe asthmatic patients with virus detected. Our results suggest that in severe asthmatics in a non-exacerbating state, the presence of virus resulted in overall poorer asthma control. The pattern of cytokine elevation seen in asthmatic patients with virus detected may provide insight to the pathophysiology involved.

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