46 research outputs found
A review of cardiac tumors
The intention of the review is to highlight the clinical presentation and established surgical technique in the management of this relatively uncommon cardiac pathology. Intracardiac masses may be encountered by a cardiologist or cardiac surgeon, and a comprehensive knowledge of the various diagnostic modalities is therefore essential. More crucial are the likely probabilities, based on an amalgamation of the clinical features, echocardiographic and radiographic findings. If surgical management is undertaken, the intra-operative finding is ultimately correlated with the histopathological diagnosis. In the review, we emphasise the necessity of a multidisciplinary approach to management of these tumors. The cumulative experience of the various members of the team collectively enables increasingly accurate diagnoses to be made preoperatively, with appropriate surgical management carried out timeously
Thinner Regions of Intracranial Aneurysm Wall Correlate with Regions of Higher Wall Shear Stress: A 7T MRI Study
BACKGROUND AND PURPOSE: Both hemodynamics and aneurysm wall thickness are important parameters in aneurysm pathophysiology. Our aim was to develop a method for semi-quantitative wall thickness assessment on in vivo 7T MR images of intracranial aneurysms for studying the relation between apparent aneurysm wall thickness and wall shear stress.
MATERIALS AND METHODS: Wall thickness was analyzed in 11 unruptured aneurysms in 9 patients who underwent 7T MR imaging with a TSE-based vessel wall sequence (0.8-mm isotropic resolution). A custom analysis program determined the in vivo aneurysm wall intensities, which were normalized to the signal of nearby brain tissue and were used as measures of apparent wall thickness. Spatial wall thickness variation was determined as the interquartile range in apparent wall thickness (the middle 50% of the apparent wall thickness range). Wall shear stress was determined by using phase-contrast MR imaging (0.5-mm isotropic resolution). We performed visual and statistical comparisons (Pearson correlation) to study the relation between wall thickness and wall shear stress.
RESULTS: 3D colored apparent wall thickness maps of the aneurysms showed spatial apparent wall thickness variation, which ranged from 0.07 to 0.53, with a mean variation of 0.22 (a variation of 1.0 roughly means a wall thickness variation of 1 voxel [0.8 mm]). In all aneurysms, apparent wall thickness was inversely related to wall shear stress (mean correlation coefficient, −0.35; P < .05).
CONCLUSIONS: A method was developed to measure the wall thickness semi-quantitatively, by using 7T MR imaging. An inverse correlation between wall shear stress and apparent wall thickness was determined. In future studies, this noninvasive method can be used to assess spatial wall thickness variation in relation to pathophysiologic processes such as aneurysm growth and rupture
Effects of Physical Exercise Training on Cerebral Blood Flow Measurements:A Systematic Review of Human Intervention Studies
The aim of this systematic review was to examine the effects of physical exercise training on cerebral blood flow (CBF), which is a physiological marker of cerebrovascular function. Relationships between training-induced effects on CBF with changes in cognitive performance were also discussed. A systematic search was performed up to July 2022. Forty-five intervention studies with experimental, quasi-experimental, or pre-post designs were included. Sixteen studies (median duration: 14 weeks) investigated effects of physical exercise training on CBF markers using magnetic resonance imaging, 20 studies (median duration: 14 weeks) used transcranial Doppler ultrasound, and eight studies (median duration: 8 weeks) used near-infrared spectroscopy. Studies using magnetic resonance imaging observed consistent increases in CBF in the anterior cingulate cortex and hippocampus, but not in whole-brain CBF. Effects on resting CBF-measured with transcranial Doppler ultrasound and near-infrared spectroscopy-were variable, while middle cerebral artery blood flow velocity increased in some studies following exercise or hypercapnic stimuli. Interestingly, concomitant changes in physical fitness and regional CBF were observed, while a relation between training-induced effects on CBF and cognitive performance was evident. In conclusion, exercise training improved cerebrovascular function because regional CBF was changed. Studies are however still needed to establish whether exercise-induced improvements in CBF are sustained over longer periods of time and underlie the observed beneficial effects on cognitive performance.</p
Intracranial aneurysms: risk factors for development and rupture
Intracranial aneurysms occur in approximately 3% of the population. The pathogenesis of aneurysms is largely unknown, and is thought to be a complex process in which both genetic and environmental factors are involved. Aneurysms can rupture and give rise to subarachnoid haemorrhage, a devastating subtype of stroke with high morbidity and mortality. Treatment can prevent rupture, but carries a risk of major complications including death. The annual risk of rupture of an aneurysm lies around 1%, indicating that the majority of aneurysms never ruptures. Therefore, preventive treatment should be restricted to those aneurysms with high risk of rupture. However, only a limited amount of risk factors are available. Therefore, better risk factors to predict aneurysm rupture are urgently needed. In this thesis, a systematic review and meta-analysis led to the identification of irregular shape of the aneurysm as an additional risk factor for use in rupture risk prediction of aneurysms in clinical practice. This review also gives an overview of risk factors with potential for use in clinical practice, for which further research is needed. Furthermore, in a study of 624 patients with subarachnoid haemorrhage no association was found between aneurysm size and the six genetic risk loci identified in the genome wide association study on intracranial aneurysms. RNA sequencing analysis of intracranial aneurysm walls revealed the role of extracellular matrix pathways and immunoglobulins in the development of aneurysms, and immune response pathways and the lysosome pathway in rupture of aneurysms. Finally, this thesis showed that 7.0 Tesla MRI has potential for studying new risk factors for aneurysm rupture. MRI signal intensity variation reflects actual thickness variation in the aneurysm wall when using a 7.0 Tesla MRI vessel wall sequence. A method was developed to quantify and compare thickness variation between different patients, and this method can be used to study aneurysm wall thickness variation as a risk factor for growth or rupture of aneurysms. This method was also used to study the association between wall thickness variation and wall shear stress, and showed that thinner regions correlate with regions of higher wall shear stress. Pulsatility (the change in volume of the aneurysm during the cardiac cycle) is a potential risk factor for rupture, and was studied on 7.0 Tesla MRI. However, it was concluded that volume pulsation quantification is not accurate with the current imaging protocol, due to multiple imaging artefacts
Gadolinium Enhancement of the Aneurysm Wall in Unruptured Intracranial Aneurysms Is Associated with an Increased Risk of Aneurysm Instability: A Follow-Up Study
BACKGROUND AND PURPOSE: Previous studies have suggested that gadolinium enhancement of the wall of unruptured intracranial aneurysms on MR imaging may reflect aneurysm wall instability. However, all previous studies were cross-sectional. In this longitudinal study, we investigated whether aneurysm wall enhancement is associated with an increased risk of aneurysm instability. MATERIALS AND METHODS: We included all patients 18 years of age or older with ≥1 unruptured aneurysm from the University Medical Center Utrecht, the Netherlands, who were included in 2 previous studies with either 3T or 7T aneurysm wall MR imaging and for whom it was decided not to treat the aneurysm but to monitor it with follow-up imaging. We investigated the risk of growth or rupture during follow-up of aneurysms with and without gadolinium enhancement of the aneurysm wall at baseline and calculated the risk difference between the 2 groups with corresponding 95% confidence intervals. RESULTS: We included 57 patients with 65 unruptured intracranial aneurysms. After a median follow-up of 27 months (interquartile range, 20-31 months), growth (n = 2) or rupture (n = 2) was observed in 4 of 19 aneurysms (21%; 95% CI, 6%-54%) with wall enhancement and in zero of 46 aneurysms (0%; 95% CI, 0%-8%) without enhancement (risk difference, 21%; 95% CI, 3%-39%). CONCLUSIONS: Gadolinium enhancement of the aneurysm wall on MR imaging is associated with an increased risk of aneurysm instability. The absence of wall enhancement makes it unlikely that the aneurysm will grow or rupture in the short term. Larger studies are needed to investigate whether aneurysm wall enhancement is an independent predictor of aneurysm instability
Does olanzapine inhibit the psychomimetic effects of Δ 9
Stress-related psychiatric disorders across the life spa
Patients with Moyamoya Vasculopathy Evaluated at a Single-Center in The Netherlands; Clinical Presentation and Outcome
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