34 research outputs found

    Characterisation of the Colour Doppler Twinkle Artefact

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    This investigation involved the development of a range of Colour Doppler Twinkle Artefact phantoms to characterise and quantify the “Twinkle” artefact which is often present when an irregular structure is encountered in the imaged field of view. The artefact occurs in both colour and power Doppler ultrasound imaging and manifests as a false depiction of colour velocity information in stationary soft tissue and therefore can cause significant misdiagnosis of areas of flow within the patient. It has been hypothesised that it is generated due to a strongly reflecting medium composed of individual reflectors and therefore becomes a clinical concern when parenchymal calcifications are encountered. (Tsao et al., 2006). The aim of this study was to investigate the occurrence and magnitude of this artefact across a range of ultrasound scanners and to monitor the effects on the artefact of varying image acquisition parameters. A range of phantoms were produced that could reproducibly recreate the Twinkle artefact, the presence of which was quantified in a range of scanners (Zonare, Siemens Antares, Philips HDI and IU22). These phantoms included both fine and coarse structures as well as a flow channel in one of the phantoms, through which blood mimicking fluid was pumped. A semi-quantitative grading system was implemented and instrument controls such as pulse repetition frequency (PRF), colour write priority, greyscale gain and depth of focal zone were varied in order to determine their impact on the Twinkle artefact. Instrument control settings were found to significantly affect the intensity of this artefact, predominantly PRF showed a significant increase in the presence of this artefact. Furthermore, the extent of the artefact varied greatly across the range of scanners with Siemens Antaries and Zonare being most sensitive to the artefact. The implication of this study has shown the Twinkle artefact to be dependent on scanner specifications and instrumental parameters. With careful image optimisation, a reduction or elimination of the artefact can be achieved

    Extensibility - Validation of Workplace Learning in Higher Education - Examples and Considerations

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    The importance of effective curriculum design and development in structuring and supporting learners in their knowledge attainment has been outlined in the writings of Tyler (1949) [1] which supports the approach adopted in European Higher Education stemming from the 1999 Bologna Declaration (European Commission, 2009). These structures are assisted in part by national and European qualification frameworks and the Dublin descriptors which are explicit of the variances in knowledge, skill and competence as one progresses in higher education and training. In addition, the inclusion of learning outcomes and programme objectives in the development of comprehensive curricula has been linked to the product model of curriculum development. Informal learning is defined as learning gained through in-house training, non-accredited courses where the outcomes is known in advance but there is no associated academic credit. This paper outlines the approaches adopted by Cork Institute of Technology in considering informal learning from the workplace in curriculum design, development, delivery and assessment of academic programmes. This is considered in terms of recognising how learning happens and the structures which need to exist to build an effective system for the growth and development of incorporating workplace learning and future needs. The paper includes a discussion around the necessary frameworks identified by Cork Institute of Technology which support the development of a more informed curriculum design quality assurance cycle. This cycle seeks to incorporate flexibility into the design to facilitate individual learning pathways and specialisations, whilst maintaining academic rigour, higher learning and workplace needs. The approach adopted by CIT as outlined in this paper provides examples of how the incorporation of flexibility without compromising quality assurance in curriculum design and development can deliver outcomes more aligned to the needs of graduates and the workplace

    Whole body cardiovascular magnetic resonance imaging to stratify symptomatic and asymptomatic atherosclerotic burden in patients with isolated cardiovascular disease

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    BACKGROUND: The aim of this study was to use whole body cardiovascular magnetic resonance imaging (WB CVMR) to assess the heart and arterial network in a single examination, so as to describe the burden of atherosclerosis and subclinical disease in participants with symptomatic single site vascular disease. METHODS: 64 patients with a history of symptomatic single site vascular disease (38 coronary artery disease (CAD), 9 cerebrovascular disease, 17 peripheral arterial disease (PAD)) underwent whole body angiogram and cardiac MR in a 3 T scanner. The arterial tree was subdivided into 31 segments and each scored according to the degree of stenosis. From this a standardised atheroma score (SAS) was calculated. Cine and late gadolinium enhancement images of the left ventricle were obtained. RESULTS: Asymptomatic atherosclerotic disease with greater than 50 % stenosis in arteries other than that responsible for their presenting complain was detected in 37 % of CAD, 33 % of cerebrovascular and 47 % of PAD patients. Unrecognised myocardial infarcts were observed in 29 % of PAD patients. SAS was significantly higher in PAD patients 24 (17.5-30.5) compared to CAD 4 (2–11.25) or cerebrovascular disease patients 6 (2-10) (ANCOVA p < 0.001). Standardised atheroma score positively correlated with age (ÎČ 0.36 p = 0.002), smoking status (ÎČ 0.34 p = 0.002), and LV mass (ÎČ -0.61 p = 0.001) on multiple linear regression. CONCLUSION: WB CVMR is an effective method for the stratification of cardiovascular disease. The high prevalence of asymptomatic arterial disease, and silent myocardial infarctions, particularly in the peripheral arterial disease group, demonstrates the importance of a systematic approach to the assessment of cardiovascular disease

    Whole body cardiovascular MRI for the comparison of atherosclerotic burden and cardiac remodelling in healthy South Asian and European adults

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    Objective: To determine the feasibility of using wholebody cardiovascular MRI (WB-CVMR) to compare South Asians (SAs)-a population known to have a higher risk of cardiovascular disease (CVD) but paradoxically lower prevalence of peripheral arterial disease-and Western Europeans (WEs). Methods: 19 SAs and 38 age-, gender- and body mass index-matched WEs were recruited. All were aged 40 years and over, free from CVD and with a 10-year risk of CV

    Effects of inaccuracies in arterial path length measurement on differences in MRI and tonometry measured pulse wave velocity

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    Abstract Background Carotid-femoral pulse wave velocity (cf-PWV) and aortic PWV measured using MRI (MRI-PWV) show good correlation, but with a significant and consistent bias across studies. The aim of the current study was to evaluate whether the differences between cf.-PWV and MRI-PWV can be accounted for by inaccuracies of currently used distance measurements. Methods One hundred fourteen study participants were recruited into one of 4 groups: Type 2 diabetes melltus (T2DM) with cardiovascular disease (CVD) (n = 23), T2DM without CVD (n = 41), CVD without T2DM (n = 25) and a control group (n = 25). All participants underwent cf.-PWV, cardiac MRI and whole body MR angiography(WB-MRA). 90 study participants also underwent aortic PWV using MRI. cf.-PWVEXT was performed using a SphygmoCor device (Atcor Medical, West Ryde, Australia). The true intra-arterial pathlength was measured using the WB-MRA and then used to recalculate the cf.-PWVEXT to give a cf.-PWVMRA. Results Distance measurements were significantly lower on WB-MRA than on external tape measure (mean diff = −85.4 ± 54.0 mm,p < 0.001). MRI-PWV was significantly lower than cf.-PWVEXT (MRI-PWV = 8.1 ± 2.9 vs. cf.-PWVEXT = 10.9 ± 2.7 ms−1,p < 0.001). When cf.-PWV was recalculated using the inter-arterial distance from WB-MRA, this difference was significantly reduced but not lost (MRI-PWV = 8.1 ± 2.9 ms−1 vs. cf.-PWVMRA 9.1 ± 2.1 ms−1, mean diff = −0.96 ± 2.52 ms−1,p = 0.001). Recalculation of the PWV increased correlation with age and pulse pressure. Conclusion Differences in cf.-PWV and MRI PWV can be predominantly but not entirely explained by inaccuracies introduced by the use of simple surface measurements to represent the convoluted arterial path between the carotid and femoral arteries

    Cohort comparison study of cardiac disease and atherosclerotic burden in type 2 diabetic adults using whole body cardiovascular magnetic resonance imaging

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    BACKGROUND: Whole body cardiovascular MR (WB CVMR) combines whole body angiography and cardiac MR assessment. It is accepted that there is a high disease burden in patients with diabetes, however the quantification of the whole body atheroma burden in both arterial and cardiac disease has not been previously reported. In this study we compare the quantified atheroma burden in those individuals with and without diabetes by clinical cardiovascular disease (CVD) status. METHODS: 158 participants underwent WB CVMR, and were categorised into one of four groups: (1) type 2 diabetes mellitus (T2DM) with CVD; (2) T2DM without CVD; (3) CVD without T2DM; (4) healthy controls. The arterial tree was subdivided into 31 segments and each scored according to the degree of stenosis. From this a standardised atheroma score (SAS) was calculated. Cardiac MR and late gadolinium enhancement images of the left ventricle were obtained for assessment of mass, volume and myocardial scar assessment. RESULTS: 148 participants completed the study protocol—61 % male, with mean age of 64 ± 8.2 years. SAS was highest in those with cardiovascular disease without diabetes [10.1 (0–39.5)], followed by those with T2DM and CVD [4 (0–41.1)], then those with T2DM only [3.23 (0–19.4)] with healthy controls having the lowest atheroma score [2.4 (0–19.4)]. Both groups with a prior history of CVD had a higher SAS and left ventricular mass than those without (p < 0.001 for both). However after accounting for known cardiovascular risk factors, only the SAS in the group with CVD without T2DM remained significantly elevated. 6 % of the T2DM group had evidence of silent myocardial infarct, with this subcohort having a higher SAS than the remainder of the T2DM group [7.7 (4–19) vs. 2.8 (0–17), p = 0.024]. CONCLUSIONS: Global atheroma burden was significantly higher in those with known cardiovascular disease and without diabetes but not in those with diabetes and cardiovascular disease suggesting that cardiovascular events may occur at a lower atheroma burden in diabetes. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12933-015-0284-2) contains supplementary material, which is available to authorized users

    Kliničke praktične smjernice za perioperacijsku i poslijeoperacijsku skrb o arterijsko-venskim fistulama i umetcima za hemodijalizu u odraslih

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    KrvoĆŸilni pristup omogućuje hemodijalizu koja spaĆĄava ĆŸivot. Stoga je nuĆŸna dobra funkcija krvoĆŸilnog pristupa koja omogućuje prikladan krvni protok radi uklanjanja tvari koje se u uremiji zadrĆŸavaju u krvi bolesnika, uz istodobno sniĆŸenje rizika od sustavne infekcije na najmanju moguću mjeru. Godine 2007. Europske smjernice najbolje prakse (engl. European Best Practice Guidelines – EBPG), prethodnice trenutačne Europske najbolje bubreĆŸne prakse (engl. European Renal Best Practice – ERBP), donijele su nacrt skupine preporuka – vodiča pri donoĆĄenju odluka o upućivanju na pregled radi krvoĆŸilnog pristupa, o procjeni i nadzoru izbora pristupa te o postupcima kod komplikacija. (1) Otad su se znatno razvili ne samo dokazi na kojima se temelje ove preporuke nego i procesi nastajanja smjernica. (2) Kao odgovor na to, ERBP je aĆŸurirao prethodno djelo u suradnji s raznim stručnjacima iz tog područja uključujući i predstavnike DruĆĄtva za krvoĆŸilni pristup (engl. Vascular Access Society – VAS), kirurge za krvoĆŸilni pristup, radiologe, medicinske sestre za dijalizu, znanstvenike, bolesnike i one koji se za njih brinu. Nastojanje da se pridrĆŸavaju sve stroĆŸe metodike izrade smjernica nalagalo je određena odricanja u pogledu područja obuhvata ovih smjernica. Posljedično, one ne „pokrivaju” baĆĄ sve iste teme kao njihova prethodna verzija. Neka su područja zajednička, a neka su arhivirana da bi ustupila mjesto novim pitanjima kojima su prednost dali i pruĆŸatelji zdravstvene skrbi i oni za koje se skrbi. Odvojeno su objavljene pojedinosti postupka izbora djelokruga problematike koju su smjernice obuhvatile. (3) Nastajanje ovih smjernica slijedilo je strog proces pregleda i procjene dokaza koji se temeljio na sustavnim pregledima rezultata kliničkih istraĆŸivanja te opservacijskih podataka gdje je to bilo potrebno. Strukturirani pristup slijedio je model sustava GRADE (hrv. stupanj), koji svakoj preporuci pripisuje stupanj s obzirom na sigurnost sveukupnih dokaza te snagu. (4) Gdje je to bilo primjereno skupina za izradu smjernica unijela je nestupnjevan savjet za kliničku praksu, a koji nije proistekao iz pregleda sustavnih dokaza. Kliničke praktične smjernice iz 2019. godine specifično pokrivaju peritransplantacijske i poslijetransplantacijske aspekte arterijsko-venskih (AV) fistula i umetaka (graftova). Drugi dio, koji je bio u nastajanju kada su ove smjernice iĆĄle u tisak, pokrit će aspekte izbora krvoĆŸilnog pristupa, prijeoperacijske procjene krvnih ĆŸila i srediĆĄnje venske katetere. Unatoč nedostatku dokaza velike sigurnosti za većinu područja krvoĆŸilnih pristupa, ERBP se posvetio izradi smjernica velike kakvoće, dajući smjernicu gdje god je moguće, a popis preporuka za istraĆŸivanje ondje gdje se nije moglo uputiti smjernicom. Nadamo se da će ove smjernice i one planirane pomoći stručnoj zajednici pri donoĆĄenju odluka o postupcima, postupnicima i skrbi vezanima s krvoĆŸilnim pristupima, pomoći bolesnicima i onima koji se za njih brinu da steknu uvid u problematiku te olakĆĄati zajedničko donoĆĄenje odluka u tom području
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