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- Clement, Patricia, et al.
(författare)
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Variability of physiological brain perfusion in healthy subjects : A systematic review of modifiers. Considerations for multi-center ASL studies
- 2018
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - 0271-678X .- 1559-7016. ; 38:9, s. 1418-1437
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Forskningsöversikt (refereegranskat)abstract
- Quantitative measurements of brain perfusion are influenced by perfusion-modifiers. Standardization of measurement conditions and correction for important modifiers is essential to improve accuracy and to facilitate the interpretation of perfusion-derived parameters. An extensive literature search was carried out for factors influencing quantitative measurements of perfusion in the human brain unrelated to medication use. A total of 58 perfusion modifiers were categorized into four groups. Several factors (e.g., caffeine, aging, and blood gases) were found to induce a considerable effect on brain perfusion that was consistent across different studies; for other factors, the modifying effect was found to be debatable, due to contradictory results or lack of evidence. Using the results of this review, we propose a standard operating procedure, based on practices already implemented in several research centers. Also, a theory of ' deep MRI physiotyping' is inferred from the combined knowledge of factors influencing brain perfusion as a strategy to reduce variance by taking both personal information and the presence or absence of perfusion modifiers into account. We hypothesize that this will allow to personalize the concept of normality, as well as to reach more rigorous and earlier diagnoses of brain disorders.
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| 3. |
- Virhammar, Johan, et al.
(författare)
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Idiopathic normal pressure hydrocephalus : cerebral perfusion measured with pCASL before and repeatedly after CSF removal
- 2014
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 0271-678X .- 1559-7016. ; 34:11, s. 1771-1778
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Tidskriftsartikel (refereegranskat)abstract
- Pseudo-continuous arterial, spin labeling (pCASL) measurements were performed in 20 patients with idiopathic normal pressure hydrocephalus (iNPH) to investigate whether cerebral blood flow (CBF) increases during the first 24 hours after a cerebrospinal fluid tap test (CSF TT). Five pCASL magnetic resonance imaging (MRI) scans were performed. Two scans were performed before removal of 40 mL CSF, and the other three at 30 minutes, 4 hours, and 24 hours, respectively after the CSF TT. Thirteen different regions of interest (ROIs) were manually drawn on coregistered MR images. In patients with increased CBF in lateral and frontal white matter after the CSF TT, gait function improved more than it did in patients with decreased CBF in these regions. However, in the whole sample, there was no significant increase in CBF after CSF removal compared with baseline investigations. The repeatability of CBF measurements at baseline was high, with intraclass correlation coefficients of 0.60 to 0.90 for different ROIs, but the median regional variability was in the range of 5% to 17%. Our results indicate that CBF in white matter close to the lateral ventricles plays a role in the reversibility of symptoms after CSF removal in patients with iNPH.
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