Browsing by Subject "intracranial aneurysm"

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    Effect of Pulsatility on the Transport of Thrombin in an Idealized Cerebral Aneurysm Geometry
    (2022-01-11) Hume, Struan; Tshimanga, Jean-Marc Ilunga; Geoghegan, Patrick; Malan, Arnaud G; Ho, Wei Hua; Ngoepe, Malebogo N
    Computational models of cerebral aneurysm thrombosis are designed for use in research and clinical applications. A steady flow assumption is applied in many of these models. To explore the accuracy of this assumption a pulsatile-flow thrombin-transport computational fluid dynamics (CFD) model, which uses a symmetrical idealized aneurysm geometry, was developed. First, a steady-flow computational model was developed and validated using data from an in vitro experiment, based on particle image velocimetry (PIV). The experimental data revealed an asymmetric flow pattern in the aneurysm. The validated computational model was subsequently altered to incorporate pulsatility, by applying a data-derived flow function at the inlet boundary. For both the steady and pulsatile computational models, a scalar function simulating thrombin generation was applied at the aneurysm wall. To determine the influence of pulsatility on thrombin transport, the outputs of the steady model were compared to the outputs of the pulsatile model. The comparison revealed that in the pulsatile case, an average of 10.2% less thrombin accumulates within the aneurysm than the steady case for any given time, due to periodic losses of a significant amount of thrombin-concentrated blood from the aneurysm into the parent vessel’s bloodstream. These findings demonstrate that pulsatility may change clotting outcomes in cerebral aneurysms.
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    Open Access
    Endovascular cerebral aneurysm treatment : Long-term outcomes
    (2008) Le Feuvre, David; Taylor, Allan
    Endovascular treatment was confirmed by the International Subarachnoid aneurysm Trial1 as the treatment of choice for intracranial “berry” aneurysms. The durability of coiling and the relevance of stable neck remnants next needed to be addressed. Methods We retrospectively assessed the follow-up angiograms of patients, who presented with subarachnoid haemorrhages or IIIrd nerve palsies and had berry aneurysms treated endovascularly between 2002 and 2003, Patients were phoned to assess their wellbeing and to see whether they were back at work or not. Angiograms were assessed to ascertain percentage of aneurysm coiled at initial procedure and then stability was assessed by percentage change in the residual on later angiograms. Results Over a 1-year period 75 patients were treated endovascularly. 100% occlusion was attainable in 52% at the initial procedure and although the number of patients who attended their 3-month and 1year follow-up angiograms were 40 and 34 respectively there was a trend toward progressive thrombosis to 65% and then 82% respectively. In only 1 of the neck remnants was there growth at the 3-month angiogram. One patient bled having missed his 3-month follow-up angiogram. Although only 40% of the patients were contactable at 4 years there was no re-bleeds amongst them. Conclusion Coiling is durable as shown by our results over a 4 year period and while neck remnants may be observed any growth should be viewed as unstable and treated either endovascularly or surgically if required.