Quantification of speed-up and accuracy of multi-CPU computational flow dynamics simulations of hemodynamics in a posterior communicating artery aneurysm of complex geometry.

Background: Towards the translation of computational fluid dynamics (CFD) techniques into the clinical workflow, performance increases achieved with parallel multi-central processing unit (CPU) pulsatile CFD simulations in a patient-derived model of a bilobed posterior communicating artery aneurysm were evaluated while simultaneously monitoring changes in the accuracy of the solution.

Methods: Simulations were performed using 2, 4, 6, 8, 10 and 12 processors. In addition, a baseline simulation was obtained with a dual-core dual CPU computer of similar computational power to clinical imaging workstations.

Prediction of neuropsychological outcome after resection of temporal and extratemporal seizure foci.

Resection of seizure foci is an effective treatment for the control of medically intractable epilepsy. However, cognitive morbidity can occur as a result of surgical intervention. This morbidity is dependent on several factors, including location and extent of resection, disease characteristics, patient demographic characteristics, and functional status of the tissue to be resected.

A computational fluid dynamics study pre- and post-stent graft placement in an acute type B aortic dissection.

Purpose: To demonstrate the capability of computational fluid dynamics (CFD) for quantifying hemodynamic forces pretreatment/posttreatment in type B aortic dissection (TB-AD).

Methods: From CFD simulations initialized with dynamic magnetic resonance image data, wall shear stress (WSS) and dynamic pressure (dynP) changes post endovascular treatment were quantified.

Results: After 1 year follow-up, thoracic aortic segment was completely remodeled, and persistent, nonthrombosed false lumen in the abdominal aorta was noted.

Brain activation in complex partial seizures during switching from a the goal-directed task to a resting state: comparison of fMRI maps to the default mode network.

The default mode network (DMN) has been previously identified as a set of brain regions activated during internally directed cognition. The objective of this study was to investigate patterns of brain activation during switching between a goal-directed task and a rest period obtained from clinical functional magnetic resonance imaging (fMRI) paradigms in complex partial seizures (CPS) and age-matched controls. As part of pre-surgical evaluation with fMRI, a visually presented block-design language task was performed by eight subjects (4 CPS, 4 age-matched controls).

Impact of tear location on hemodynamics in a type B aortic dissection investigated with computational fluid dynamics.

Stanford type B aortic dissections (TB-AD), which split the descending aorta in a true and false lumen, have better in-hospital survival than type A dissections affecting the ascending aorta. However, short-term and long-term prognosis for the individual patient remains challenging, with one in four patients not surviving after 3 years.

Cost function evaluation for the registration of clinical DTI images onto the ICBM DTI81 white matter atlas.

Background And Purpose: Various algorithms are available for the analysis of diffusion tensor (DTI) images. Many of these stand alone software packages require time-intensive user interactions not yet suited for routine clinical application Here, we demonstrate the use of the 'Analysis of Functional NeuroImages' (AFNI) software package, a standard for the analysis of functional magnetic resonance images (fMRI), to automatically align clinical DTI images onto the ICBM DTI81 atlas potentially enabling the combined presentation of fMRI and DTI results.

Methods: Fractional anisotropy (FA) maps from seven patients diagnosed with video/EEG defined complex partial seizures were retrospectively analyzed.

Temporal variations of wall shear stress parameters in intracranial aneurysms--importance of patient-specific inflow waveforms for CFD calculations.

Purpose: To assess reliability of wall shear stress (WSS)calculations using computational fluid dynamics (CFD) dependent on inflow in internal carotid artery aneurysms (ICA).

Materials And Methods: Six unruptured ICA aneurysms were studied. 3D computational meshes were created from 3D digital subtraction angiographic images (Axiom Artis dBA, Siemens Medical Solutions).

Computational fluid dynamics as a tool for visualizing hemodynamic flow patterns.

Computational fluid dynamics (CFD) techniques have progressed to a point where they can be routinely applied towards the simulation of blood flow dynamics in the human vasculature. Patient-specific geometries and physiologically accurate flow rates can be obtained from clinical images to provide accurate boundary conditions for these simulations. Advances in computer hardware and CFD software in recent years have reduced the simulation computing time from days to hours.

Depressed mood and memory impairment before and after unilateral posteroventral pallidotomy in Parkinson's disease.

This study evaluated poor mood state as a moderator of changes in verbal recall ability from before to after unilateral posteroventral pallidotomy in 54 individuals with advanced Parkinson's disease. Repeated-measures analysis of covariance (controlling for motor disease severity) indicated that left-posteroventral pallidotomy subjects with depressed mood performed more poorly on measures of verbal list learning and story recall compared to nondepressed subjects or right-posteroventral pallidotomy subjects with depressed mood both before and after surgery. The results suggest that depressed mood should be taken into account when interpreting memory test performance in Parkinson's disease surgical candidates both before and after surgery.