scholarly journals Measuring the Effects of Remifentanil on Cerebral Blood Flow and Arterial Arrival Time Using 3D Grase MRI with Pulsed Arterial Spin Labelling

2008 ◽  
Vol 28 (8) ◽  
pp. 1514-1522 ◽  
Author(s):  
Bradley J Macintosh ◽  
Kyle TS Pattinson ◽  
Daniel Gallichan ◽  
Imran Ahmad ◽  
Karla L Miller ◽  
...  

Arterial spin labelling (ASL) has proved to be a promising magnetic resonance imaging (MRI) technique to measure brain perfusion. In this study, volumetric three-dimensional (3D) gradient and spin echo (GRASE) ASL was used to produce cerebral blood flow (CBF) and arterial arrival time (AAT) maps during rest and during an infusion of remifentanil. Gradient and spin echo ASL perfusion-weighted images were collected at multiple inflow times (500 to 2,500 ms in increments of 250 ms) to accurately fit an ASL perfusion model. Fit estimates were assessed using z-statistics, allowing voxels with a poor fit to be excluded from subsequent analyses. Nonparametric permutation testing showed voxels with a significant difference in CBF and AAT between conditions across a group of healthy participants ( N = 10). Administration of remifentanil produced an increase in end-tidal CO2, an increase in CBF from 57 ± 12.0 to 77 ± 18.4 mL/100 g tissue per min and a reduction in AAT from 0.73 ± 0.073 to 0.64 ± 0.076 secs. Within grey matter, remifentanil produced a cerebrovascular response of 5.7 ± 1.60 %CBF per mm Hg. Significant differences between physiologic conditions were observed in both CBF and AAT maps, indicating that 3D GRASE-ASL has the sensitivity to study changes in physiology at a voxel level.

Brain ◽  
2019 ◽  
Vol 142 (4) ◽  
pp. 1108-1120 ◽  
Author(s):  
Henri J M M Mutsaerts ◽  
Saira S Mirza ◽  
Jan Petr ◽  
David L Thomas ◽  
David M Cash ◽  
...  

Abstract Genetic forms of frontotemporal dementia are most commonly due to mutations in three genes, C9orf72, GRN or MAPT, with presymptomatic carriers from families representing those at risk. While cerebral blood flow shows differences between frontotemporal dementia and other forms of dementia, there is limited evidence of its utility in presymptomatic stages of frontotemporal dementia. This study aimed to delineate the cerebral blood flow signature of presymptomatic, genetic frontotemporal dementia using a voxel-based approach. In the multicentre GENetic Frontotemporal dementia Initiative (GENFI) study, we investigated cross-sectional differences in arterial spin labelling MRI-based cerebral blood flow between presymptomatic C9orf72, GRN or MAPT mutation carriers (n = 107) and non-carriers (n = 113), using general linear mixed-effects models and voxel-based analyses. Cerebral blood flow within regions of interest derived from this model was then explored to identify differences between individual gene carrier groups and to estimate a timeframe for the expression of these differences. The voxel-based analysis revealed a significant inverse association between cerebral blood flow and the expected age of symptom onset in carriers, but not non-carriers. Regions included the bilateral insulae/orbitofrontal cortices, anterior cingulate/paracingulate gyri, and inferior parietal cortices, as well as the left middle temporal gyrus. For all bilateral regions, associations were greater on the right side. After correction for partial volume effects in a region of interest analysis, the results were found to be largely driven by the C9orf72 genetic subgroup. These cerebral blood flow differences first appeared approximately 12.5 years before the expected symptom onset determined on an individual basis. Cerebral blood flow was lower in presymptomatic mutation carriers closer to and beyond their expected age of symptom onset in key frontotemporal dementia signature regions. These results suggest that arterial spin labelling MRI may be a promising non-invasive imaging biomarker for the presymptomatic stages of genetic frontotemporal dementia.


2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Adnan Bibic ◽  
Tea Sordia ◽  
Erik Henningsson ◽  
Linda Knutsson ◽  
Freddy Ståhlberg ◽  
...  

Abstract Background Our aim was to introduce damaged red blood cells (RBCs) as a tool for haemodynamic provocation in rats, hypothesised to cause decreased cerebral blood flow (CBF) and prolonged water capillary transfer time (CTT), and to investigate whether expected changes in CBF could be observed and if haemodynamic alterations were reflected by the CTT metric. Methods Damaged RBCs exhibiting a mildly reduced deformability were injected to cause aggregation of RBCs. Arterial spin labelling (ASL) magnetic resonance imaging experiments were performed at 9.4 T. Six datasets (baseline plus five datasets after injection) were acquired for each animal in a study group and a control group (13 and 10 female adult Wistar rats, respectively). For each dataset, ASL images at ten different inversion times were acquired. The CTT model was adapted to the use of a measured arterial input function, implying the use of a realistic labelling profile. Repeated measures ANOVA was used (alpha error = 0.05). Results After injection, significant differences between the study group and control group were observed for relative CBF in white matter (up to 20 percentage points) and putamen (up to 18–20 percentage points) and for relative CTT in putamen (up to 35–40 percentage points). Conclusions Haemodynamic changes caused by injection of damaged RBCs were observed by ASL-based CBF and CTT measurements. Damaged RBCs can be used as a tool for test and validation of perfusion imaging modalities. CTT model fitting was challenging to stabilise at experimental signal-to-noise ratio levels, and the number of free parameters was minimised.


2020 ◽  
pp. 197140092097703
Author(s):  
Deepasree Jaganmohan ◽  
Somnath Pan ◽  
Chandrasekharan Kesavadas ◽  
Bejoy Thomas

Arterial spin labelling is an emerging non-invasive magnetic resonance imaging technique for estimating the cerebral perfusion without the requirement for gadolinium-based intravenous contrast agents. Despite the wide range of applications in epilepsy, dementia, brain tumours, vascular malformations and stroke imaging, obtaining clinically useful arterial spin labelling data is technically challenging and prone to numerous artefacts. The objective of this review is to provide a comprehensive pictorial overview of the various artefacts associated with arterial spin labelling, particularly three-dimensional fast spin echo pseudocontinuous arterial spin labelling with spiral readout. These artefacts could be broadly classified as those occurring during the magnetic labelling, arterial transit or image acquisition. Arterial spin labelling artefacts of clinical diagnostic utility are also elaborated. A thorough knowledge of the basis of these artefacts will avoid diagnostic pitfalls while interpreting arterial spin labelling images. Important tips to reduce or overcome these artefacts are also discussed.


2014 ◽  
Vol 32 (5) ◽  
pp. 497-504 ◽  
Author(s):  
Camille Maumet ◽  
Pierre Maurel ◽  
Jean-Christophe Ferré ◽  
Christian Barillot

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