scholarly journals Impact of the inversion time on regional brain perfusion estimation with clinical arterial spin labeling protocols

2021 ◽  
Author(s):  
Francesco Sanvito ◽  
Fulvia Palesi ◽  
Elisa Rognone ◽  
Leonardo Barzaghi ◽  
Ludovica Pasca ◽  
...  
Keyword(s):  
Arterial Spin Labeling ◽  
Insular Cortex ◽  
Brain Perfusion ◽  
Occipital Cortex ◽  
Spin Labeling ◽  
Patient Specific ◽  
Visual Evaluation ◽  
Inversion Time ◽  
Arterial Transit Time ◽  
The Impact

Abstract Objective Evaluating the impact of the Inversion Time (TI) on regional perfusion estimation in a pediatric cohort using Arterial Spin Labeling (ASL). Materials and methods Pulsed ASL (PASL) was acquired at 3 T both at TI 1500 ms and 2020 ms from twelve MRI-negative patients (age range 9–17 years). A volume of interest (VOIs) and a voxel-wise approach were employed to evaluate subject-specific TI-dependent Cerebral Blood Flow (CBF) differences, and grey matter CBF Z-score differences. A visual evaluation was also performed. Results CBF was higher for TI 1500 ms in the proximal territories of the arteries (PTAs) (e.g. insular cortex and basal ganglia — P < 0.01 and P < 0.05 from the VOI analysis, respectively), and for TI 2020 ms in the distal territories of the arteries (DTAs), including the watershed areas (e.g. posterior parietal and occipital cortex — P < 0.001 and P < 0.01 from the VOI analysis, respectively). Similar differences were also evident when analyzing patient-specific CBF Z-scores and at a visual inspection. Conclusions TI influences ASL perfusion estimates with a region-dependent effect. The presence of intraluminal arterial signal in PTAs and the longer arterial transit time in the DTAs (including watershed areas) may account for the TI-dependent differences. Watershed areas exhibiting a lower perfusion signal at short TIs (~ 1500 ms) should not be misinterpreted as focal hypoperfused areas.

scholarly journals Reliability and Reproducibility of Hadamard Encoded Pseudo-Continuous Arterial Spin Labeling in Healthy Elderly

2021 ◽  
Vol 15 ◽  
Author(s):  
Katja Neumann ◽  
Martin Schidlowski ◽  
Matthias Günther ◽  
Tony Stöcker ◽  
Emrah Düzel
Keyword(s):  
Arterial Spin Labeling ◽  
Signal To Noise Ratio ◽  
Brain Perfusion ◽  
Spin Labeling ◽  
Healthy Elderly ◽  
Perfusion Studies ◽  
Coefficients Of Variation ◽  
Arterial Transit Time ◽  
Magnetic Resonance Imaging Mri ◽  
Continuous Arterial Spin Labeling

The perfusion parameters cerebral blood flow (CBF) and arterial transit time (ATT) measured with arterial spin labeling (ASL) magnetic resonance imaging (MRI) provide valuable essentials to assess the integrity of cerebral tissue. Brain perfusion changes, due to aging, an intervention, or neurodegenerative diseases for example, could be investigated in longitudinal ASL studies with reliable ASL sequences. Generally, pseudo-continuous ASL (pCASL) is preferred because of its larger signal-to-noise ratio (SNR) compared to pulsed ASL (PASL) techniques. Available pCASL versions differ regarding their feature details. To date only little is known about the reliability and reproducibility of CBF and ATT measures obtained with the innovative Hadamard encoded pCASL variant, especially if applied on participants in old age. Therefore, we investigated an in-house developed Hadamard encoded pCASL sequence on a group of healthy elderly at two different 3 Tesla Siemens MRI systems (Skyra and mMR Biograph) and evaluated CBF and ATT reliability and reproducibility for several regions-of-interests (ROI). Calculated within-subject coefficients of variation (wsCV) demonstrated an excellent reliability of perfusion measures, whereas ATT appeared to be even more reliable than CBF [e.g., wsCV(CBF) = 2.9% vs. wsCV(ATT) = 2.3% for a gray matter (GM) ROI on Skyra system]. Additionally, a substantial agreement of perfusion values acquired on both MRI systems with an inter-session interval of 78 ± 17.6 days was shown by high corresponding intra-class correlation (ICC) coefficients [e.g., ICC(CBF) = 0.704 and ICC(ATT) = 0.754 for a GM ROI]. The usability of this novel Hadamard encoded pCASL sequence might improve future follow-up perfusion studies of the aging and/or diseased brain.

Challenges for Non-Invasive Brain Perfusion Quantification Using Arterial Spin Labeling

2011 ◽  
Vol 24 (1) ◽  
pp. 77-83 ◽  
Author(s):  
I. Sousa ◽  
N. Santos ◽  
J. Sanches ◽  
P. Vilela ◽  
P. Figueiredo
Keyword(s):  
Arterial Spin Labeling ◽  
Brain Perfusion ◽  
Spin Labeling ◽  
Non Invasive ◽  
Perfusion Quantification

scholarly journals Patient-Specific Detection of Cerebral Blood Flow Alterations as Assessed by Arterial Spin Labeling in Drug-Resistant Epileptic Patients

PLoS ONE ◽  
2015 ◽  
Vol 10 (5) ◽  
pp. e0123975 ◽  
Author(s):  
Ilaria Boscolo Galazzo ◽  
Silvia Francesca Storti ◽  
Alessandra Del Felice ◽  
Francesca Benedetta Pizzini ◽  
Chiara Arcaro ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Arterial Spin Labeling ◽  
Spin Labeling ◽  
Patient Specific ◽  
Drug Resistant ◽  
Specific Detection ◽  
Epileptic Patients

scholarly journals Mapping Brain Function Using a 30-Day Interval between Baseline and Activation: A Novel Arterial Spin Labeling fMRI Approach

2010 ◽  
Vol 30 (10) ◽  
pp. 1721-1733 ◽  
Author(s):  
Ajna Borogovac ◽  
Christian Habeck ◽  
Scott A Small ◽  
Iris Asllani
Keyword(s):  
Brain Function ◽  
Arterial Spin Labeling ◽  
Signal To Noise Ratio ◽  
Spin Labeling ◽  
Flow Density ◽  
Functional Changes ◽  
Young Subjects ◽  
Arterial Transit Time ◽  
Acute Changes

By comparing hemodynamic signals acquired immediately before and during activation, functional magnetic resonance imaging (fMRI) is well suited for mapping acute changes in brain function. However, it remains unclear whether fMRI can map functional changes over longer periods. Here, we address this issue by empirically testing the feasibility of arterial spin labeling (ASL) fMRI to detect changes in cerebral blood flow (CBF) with baseline and task separated by 1 month. To increase the sensitivity of the method, we applied an algorithm that yielded flow density (CBFd) images that were independent of tissue content. To increase the accuracy, we developed a technique that generated arterial transit time at each voxel, independently. Results showed that activation changes in CBFd during the same session were statistically the same as across 30 days. The activation CBFd on day-30 was 34% (motor) and 25% (visual) higher than the respective baselines of 83 and 107 mL/100 g/min obtained on day-1. Furthermore, the signal-to-noise ratio of the CBFd measurement was 2.1 and 2.9 times higher than that of the conventional CBF for within-subject and across-subjects comparisons, respectively ( n=9 healthy young subjects). Taken together, these results indicate that CBFd measure could be better suited than net CBF to map long-term changes in brain function.

scholarly journals A Combined Computational Fluid Dynamics and Arterial Spin Labeling MRI Modeling Strategy to Quantify Patient-Specific Cerebral Hemodynamics in Cerebrovascular Occlusive Disease

2021 ◽  
Vol 9 ◽  
Author(s):  
Jonas Schollenberger ◽  
Nicholas H. Osborne ◽  
Luis Hernandez-Garcia ◽  
C. Alberto Figueroa
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Blood Supply ◽  
Arterial Spin Labeling ◽  
Spin Labeling ◽  
Cerebral Hemodynamics ◽  
Occlusive Disease ◽  
Patient Specific ◽  
Cfd Model ◽  
Cerebrovascular Occlusive Disease

Cerebral hemodynamics in the presence of cerebrovascular occlusive disease (CVOD) are influenced by the anatomy of the intracranial arteries, the degree of stenosis, the patency of collateral pathways, and the condition of the cerebral microvasculature. Accurate characterization of cerebral hemodynamics is a challenging problem. In this work, we present a strategy to quantify cerebral hemodynamics using computational fluid dynamics (CFD) in combination with arterial spin labeling MRI (ASL). First, we calibrated patient-specific CFD outflow boundary conditions using ASL-derived flow splits in the Circle of Willis. Following, we validated the calibrated CFD model by evaluating the fractional blood supply from the main neck arteries to the vascular territories using Lagrangian particle tracking and comparing the results against vessel-selective ASL (VS-ASL). Finally, the feasibility and capability of our proposed method were demonstrated in two patients with CVOD and a healthy control subject. We showed that the calibrated CFD model accurately reproduced the fractional blood supply to the vascular territories, as obtained from VS-ASL. The two patients revealed significant differences in pressure drop over the stenosis, collateral flow, and resistance of the distal vasculature, despite similar degrees of clinical stenosis severity. Our results demonstrated the advantages of a patient-specific CFD analysis for assessing the hemodynamic impact of stenosis.

scholarly journals Effects of Acquisition Parameter Modifications and Field Strength on the Reproducibility of Brain Perfusion Measurements Using Arterial Spin-Labeling

2020 ◽  
Vol 42 (1) ◽  
pp. 109-115
Author(s):  
K.P.A. Baas ◽  
J. Petr ◽  
J.P.A. Kuijer ◽  
A.J. Nederveen ◽  
H.J.M.M. Mutsaerts ◽  
...  
Keyword(s):  
Field Strength ◽  
Arterial Spin Labeling ◽  
Brain Perfusion ◽  
Spin Labeling ◽  
Perfusion Measurements

Arterial spin labeling magnetic resonance imaging at short post-labeling delay reflects cerebral perfusion pressure verified by oxygen-15-positron emission tomography in cerebrovascular steno-occlusive disease

2020 ◽  
pp. 028418512091711
Author(s):  
Hiroshi Itagaki ◽  
Yasuaki Kokubo ◽  
Kanako Kawanami ◽  
Shinji Sato ◽  
Yuki Yamada ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Arterial Spin Labeling ◽  
Cerebral Perfusion ◽  
Perfusion Pressure ◽  
Spin Labeling ◽  
Occlusive Disease ◽  
Resonance Imaging ◽  
Arterial Transit Time ◽  
The Right

Background Arterial transit time correction by data acquisition with multiple post-labeling delays (PLDs) or relatively long PLDs is expected to obtain more accurate imaging in cases of the cerebrovascular steno-occlusive disease. However, there have so far been no reports describing the significance of arterial spin labeling (ASL) images at short PLDs regarding the evaluation of cerebral circulation in ischemic cerebrovascular disease. Purpose To clarify the role of short-PLD ASL in cerebrovascular steno-occlusive disease. Material and Methods Fifty-three patients with cerebrovascular steno-occlusive disease were included in this study. All patients underwent ASL magnetic resonance imaging and 15O-PET within two days of each modality. To compare the ASL findings with each parameter of PET, the right-to-left (R/L) ratio, defined as the right middle cerebral artery (MCA) value/left MCA value, was calculated. Results There is a significant correlation between the ASL images at a short PLD and the ratio of cerebral blood flow and cerebral blood volume by 15O-PET, which may accurately reflect the cerebral perfusion pressure. A receiver operating characteristic curve analysis indicated that ASL images at PLD 1000 and 1500 ms were more accurate than at PLD 2000–3000 ms for the detection of a ≥10% change in the PET cerebral blood flow. Conclusion ASL images at shorter PLDs may be useful at least as a screening modality to detect the changes in the cerebral circulation in cerebrovascular steno-occlusive disease. We must evaluate ASL images at multiple PLDs while considering the arterial transit time of each case at present.

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