Changes In Cerebral Blood Flow Research Articles

Intensive antihypertensive treatment does not lower cerebral blood flow or cause orthostatic hypotension in frail older adults

AbstractThis study aimed to examine the effects of intensive antihypertensive treatment (AHT), i.e., systolic blood pressure target ≤ 140 mmHg, on cerebral blood flow, cerebral autoregulation, and orthostatic hypotension, in a representative population of frail older adults. Fourteen frail hypertensive patients (six females; age 80.3 ± 5.2 years; Clinical Frailty Scale 4–7; unattended SBP ≥ 150 mmHg) underwent measurements before and after a median 7-week AHT targeting SBP ≤ 140 mmHg. Transcranial Doppler measurements of middle cerebral artery velocity (MCAv), reflecting changes in cerebral blood flow (CBF), were combined with finger plethysmography recordings of continuous BP. Transfer function analysis assessed cerebral autoregulation (CA). ANCOVA analysed AHT-induced changes in CBF and CA and evaluated non-inferiority of the relative change in CBF (margin: -10%; covariates: pre-AHT values and AHT-induced relative mean BP change). McNemar-tests analysed whether the prevalence of OH and initial OH, assessed by sit/supine-to-stand challenges, increased with AHT. Unattended mean arterial pressure decreased by 15 mmHg following AHT. Ten (71%) participants had good quality TCD assessments. Non-inferiority was confirmed for the relative change in MCAv (95%CI: -2.7, 30.4). CA remained normal following AHT (P > 0.05), and the prevalence of OH and initial OH did not increase (P ≥ 0.655). We found that AHT in frail, older patients does not reduce CBF, impair autoregulation, or increase (initial) OH prevalence. These observations may open doors for more intensive AHT targets upon individualized evaluation and monitoring of hypertensive frail patients.Clinical Trial Registration: This study is registered at ClinicalTrials.gov (NCT05529147; September 1, 2022) and EudraCT (2022-001283-10; June 28, 2022).

Early-treatment cerebral blood flow change as a predictive biomarker of antidepressant treatment response: evidence from the EMBARC clinical trial.

Major depressive disorder (MDD) is one of the most prevalent and disabling illnesses worldwide. Treatment of MDD typically relies on trial-and-error to find an effective approach. Identifying early response-related biomarkers that predict response to antidepressants would help clinicians to decide, as early as possible, whether a particular treatment might be suitable for a given patient. Data were from the two-stage Establishing Moderators and Biosignatures of Antidepressant Response for Clinical Care (EMBARC) trial. A whole-brain, voxel-wise, mixed-effects model was applied to identify early-treatment cerebral blood flow (CBF) changes as biomarkers of treatment response. We examined changes in CBF measured with arterial spin labeling 1-week after initiating double-masked sertraline/placebo. We tested whether these early 1-week scans could be used to predict response observed after 8-weeks of treatment. Response to 8-week placebo treatment was associated with increased cerebral perfusion in temporal cortex and reduced cerebral perfusion in postcentral region captured at 1-week of treatment. Additionally, CBF response in these brain regions was significantly correlated with improvement in Hamilton Depression Rating Scale score in the placebo group. No significant associations were found for selective serotonin reuptake inhibitor treatment. We conclude that early CBF responses to placebo administration in multiple brain regions represent candidate neural biomarkers of longer-term antidepressant effects.

Endothelial dysfunction in neurodegenerative disease: Is endothelial inflammation an overlooked druggable target?

Neurological diseases with a neurodegenerative component have been associated with alterations in the cerebrovasculature. At the anatomical level, these are centred around changes in cerebral blood flow and vessel organisation. At the molecular level, there is extensive expression of cellular adhesion molecules and increased release of pro-inflammatory mediators. Together, these has been found to negatively impact blood-brain barrier integrity. Systemic inflammation has been found to accelerate and exacerbate endothelial dysfunction, neuroinflammation and degeneration. Here, we review the role of cerebrovasculature dysfunction in neurodegenerative disease and discuss the potential contribution of intermittent pro-inflammatory systemic disease in causing endothelial pathology, highlighting a possible mechanism that may allow broad-spectrum therapeutic targeting in the future.

Hippocampal volume mediates the association of arterial stiffness with cognitive impairment in adult population.

To investigate the association of arterial stiffness with brain perfusion, brain tissue volume and cognitive impairment in the general adult population. This prospective study included 1488 adult participants (age range: 22.8-83.9 years) from the Kailuan study. All participants underwent brachial-ankle pulse wave velocity (PWV) measurement, brain MRI, and Montreal Cognitive Assessment (MoCA). The association of PWV with cerebral blood flow (CBF), brain tissue volume and MoCA score was investigated. Mediation analysis was used to determine whether CBF and brain tissue volume changes mediated the associations between PWV and MoCA score. A 1 standard deviation (SD) increase in PWV was associated with lower total brain CBF [β (95% CI) -0.67 (-1.2 to -0.14)], total gray matter CBF [β (95% CI) -0.7 [-1.27 to -0.13)], frontal lobe CBF [β (95% CI) -0.59 (-1.17 to -0.01)], parietal lobe CBF [β (95% CI) -0.8 (-1.43 to -0.18)], and temporal lobe CBF [β (95% CI) -0.68 (-1.24 to -0.12)]. Negative associations were found for PWV and total brain volume [β (95% CI) -4.8 (-7.61 to -1.99)] and hippocampus volume [β (95% CI) -0.08 (-0.13 to -0.04)]. A 1 SD increase PWV was significantly associated with elevated odds of developing cognitive impairment [odds ratio (95% CI) 1.21 (1.01-1.45)]. Mediation analysis showed that hippocampal volume partially mediated the negative association between PWV and MoCA scores (proportion: 14.173%). High arterial stiffness was associated with decreased total and regional CBF, brain tissue volume, and cognitive impairment. Hippocampal volume partially mediated the effects of arterial stiffness on cognitive impairment.

Changes of motor symptoms and regional cerebral blood flow after transcranial direct current stimulation in Parkinson's disease

Changes of motor symptoms and regional cerebral blood flow after transcranial direct current stimulation in Parkinson's disease

Cerebral blood flow regulation in hypobaric hypoxia: role of haemoconcentration.

During acute hypoxic exposure, cerebral blood flow (CBF) increases to compensate for the reduced arterial oxygen content (CaO2). Nevertheless, as exposure extends, both CaO2 and CBF progressively normalize. Haemoconcentration is the primary mechanism underlying the CaO2 restoration and may therefore explain, at least in part, the CBF normalization. Accordingly, we tested the hypothesis that reversing the haemoconcentration associated with extended hypoxic exposure returns CBF towards the values observed in acute hypoxia. Twenty-three healthy lowlanders (12 females) completed two identical 4-day sojourns in a hypobaric chamber, one in normoxia (NX) and one in hypobaric hypoxia (HH, 3500m). CBF was measured by ultrasound after 1, 6, 12, 48 and 96h and compared between sojourns to assess the time course of changes in CBF. In addition, CBF was measured at the end of the HH sojourn after hypervolaemic haemodilution. Compared with NX, CBF was increased in HH after 1h (P=0.001) but similar at all later time points (all P>0.199). Haemoglobin concentration was higher in HH than NX from 12h to 96h (all P<0.001). While haemodilution reduced haemoglobin concentration from 14.8 ± 1.0 to 13.9 ± 1.2g·dl-1 (P<0.001), it did not increase CBF (974 ± 282 to 872 ± 200ml·min-1; P=0.135). We thus conclude that, at least at this moderate altitude, haemoconcentration is not the primary mechanism underlying CBF normalization with acclimatization. These data ostensibly reflect the fact that CBF regulation at high altitude is a complex process that integrates physiological variables beyond CaO2. KEY POINTS: Acute hypoxia causes an increase in cerebral blood flow (CBF). However, as exposure extends, CBF progressively normalizes. We investigated whether hypoxia-induced haemoconcentration contributes to the normalization of CBF during extended hypoxia. Following 4 days of hypobaric hypoxic exposure (corresponding to 3500m altitude), we measured CBF before and after abolishing hypoxia-induced haemoconcentration by hypervolaemic haemodilution. Contrary to our hypothesis, the haemodilution did not increase CBF in hypoxia. Our findings do not support haemoconcentration as a stimulus for the CBF normalization during extended hypoxia.

Validating the reproducibility of a low-cost single-channel fNIRS device across hierarchical cognitive tasks.

This study evaluates a low-cost, single-channel fNIRS device in cognitive neuroscience, aiming to overcome the financial barriers of commercial systems by testing its efficacy in tasks of varying complexity. Twenty-six participants engaged in motor control (finger-tapping), working memory (n-back), and creativity (AUT) tasks while their prefrontal cortex activity was monitored using the device, with behavioral and cerebral blood flow changes recorded. Results showed the device's capability to detect significant blood flow variations across different tasks, thereby supporting its use in cognitive research. The study confirms the potential of single-channel fNIRS as a cost-effective tool for diverse cognitive assessments, from simple motor actions to complex creative thinking.

Longitudinal alterations in brain perfusion and vascular reactivity in the zQ175DN mouse model of Huntington’s disease

BackgroundHuntington’s disease (HD) is marked by a CAG-repeat expansion in the huntingtin gene that causes neuronal dysfunction and loss, affecting mainly the striatum and the cortex. Alterations in the neurovascular coupling system have been shown to lead to dysregulated energy supply to brain regions in several neurological diseases, including HD, which could potentially trigger the process of neurodegeneration. In particular, it has been observed in cross-sectional human HD studies that vascular alterations are associated to impaired cerebral blood flow (CBF). To assess whether whole-brain changes in CBF are present and follow a pattern of progression, we investigated both resting-state brain perfusion and vascular reactivity longitudinally in the zQ175DN mouse model of HD.MethodsUsing pseudo-continuous arterial spin labelling (pCASL) MRI in the zQ175DN model of HD and age-matched wild-type (WT) mice, we assessed whole-brain, resting-state perfusion at 3, 6 and 9 and 13 months of age, and assessed hypercapnia-induced cerebrovascular reactivity (CVR), at 4.5, 6, 9 and 15 months of age.ResultsWe found increased perfusion in cortical regions of zQ175DN HET mice at 3 months of age, and a reduction of this anomaly at 6 and 9 months, ages at which behavioural deficits have been reported. On the other hand, under hypercapnia, CBF was reduced in zQ175DN HET mice as compared to the WT: for multiple brain regions at 6 months of age, for only somatosensory and retrosplenial cortices at 9 months of age, and brain-wide by 15 months. CVR impairments in cortical regions, the thalamus and globus pallidus were observed in zQ175DN HET mice at 9 months, with whole brain reactivity diminished at 15 months of age. Interestingly, blood vessel density was increased in the motor cortex at 3 months, while average vessel length was reduced in the lateral portion of the caudate putamen at 6 months of age.ConclusionOur findings reveal early cortical resting-state hyperperfusion and impaired CVR at ages that present motor anomalies in this HD model, suggesting that further characterization of brain perfusion alterations in animal models is warranted as a potential therapeutic target in HD.

Cerebral blood flow changes in maintenance hemodialysis patients with restless legs syndrome and their clinical significance:a cross-sectional case-control study

ObjectiveRestless legs syndrome (RLS) stands as a prevalent neurological complication within maintenance hemodialysis (MHD) patients. However, the alterations in cerebral blood flow (CBF) among MHD-RLS patients remain uncharted. Through the utilization of the arterial spin labeling (ASL) technique, we evaluated the fluctuations in CBF within distinct brain regions and analyzed the risk factors for the development of RLS in MHD patients in the context of the clinic.MethodsThirty-one MHD patients with concomitant RLS (MHD-RLS group) and thirty-one non-RLS patients matched based on age, gender, as well as cognitive function (MHD-nRLS group) were included. Through image preprocessing and data analysis, the changes in CBF values in distinct brain regions were obtained, and the CBF values of brain regions with substantial differences between the two groups were correlated with the RLS scores. Furthermore, the differences in baseline data were compared, and through the utilization of multifactorial logistic regression, the independent risk factors for the development of RLS were examined.ResultsCompared with the MHD-nRLS group, the MHD-RLS group had increased CBF in the right superior temporal gyrus, reduced CBF in the right hippocampus, left middle frontal gyrus, inferior frontal gyrus of right triangle, middle frontal gyrus of left orbit, left precentral gyrus, and left precuneus. Only left precentral gyrus CBF were negatively correlated with RLS scores after correction for dialysis duration(r = -0.436, P = 0.016). Accordingly, multifactorial regression analysis by stepwise method yielded that the left precentral gyrus CBF values(OR: 0.968, 95%CI: 0.944–0.993, P = 0.012) remained an independent risk factor for RLS in MHD patients. In addition, the results showed that hemodialysis duration (OR: 1.055, 95%CI: 1.014–1.098, P = 0.008) and serum iron levels (OR: 0.685, 95%CI: 0.551–0.852, P = 0.001) were also risk factors for the development of RLS.ConclusionPatients afflicted with MHD-RLS exhibit alterations in CBF across several brain regions. Notably, the left precentral gyrus might serve as a pivotal region influencing the onset of RLS among MHD patients. Furthermore, extended hemodialysis duration and a relative insufficiency in serum iron levels independently contribute as risk factors for RLS development within the MHD patient population.

Temporal Changes in Cerebral Blood Flow during Migraine with Aura of Alternating Left and Right Homonymous Hemianopsia.

A 16-year-old boy presented with sudden left homonymous hemianopsia followed by right ocular and occipital pain. Arterial spin labeling (ASL), a non-contrast magnetic resonance imaging technique used to evaluate perfusion, showed a decrease in cerebral blood flow in the right occipital lobe. Three hours after admission, the patient experienced right homonymous hemianopsia and ocular-to-occipital pain on the contralateral side. ASL revealed a decreased cerebral blood flow in the left occipital lobe. We ultimately diagnosed the patient with first-time migraine with aura, in which cortical spreading depression was visualized as decreased cerebral blood flow using ASL.

Shenqi Yizhi prescription prevents AβO-induced memory impairment in mice by regulating the contractility of brain pericytes

BackgroundCerebral microcirculation disturbance manifested by decrease of cerebral blood flow (CBF) is one of early features of Alzheimer's disease (AD). Shenqi Yizhi prescription (SQYZ) is widely used in the treatment of AD. However, the effect of SQYZ on the early feature of AD is not clarified. PurposeTo explore the effect and mechanism of SQYZ on AD-like behavior from the perspective of early pathological features of AD. MethodsThe fingerprint of SQYZ was established by ultra-high-performance liquid chromatograph. The improvement effect of SQYZ on Aβ1–42 Oligomer (AβO)-induced AD-like behavior of mice was evaluated by behavioral test. The changes of CBF were detected by laser doppler meter and laser speckle imaging. The pathological changes of the hippocampus were observed by HE staining and transmission electron microscope. The expressions of intercellular communication molecules were detected by western blotting or immunofluorescence staining. The content of platelet-derived growth factor-BB (PDGF-BB) was detected by ELISA. Finally, the core components of SQYZ were docked with platelet-derived growth factor receptor beta (PDGFRβ) using AutoDock Vina software. ResultsThe similarity of the components in SQYZ extracted from different batches of medicinal materials was higher than 0.9. SQYZ administration could improve AβO-induced memory impairment and CBF reduction. Compared with the sham group, the number of neurons in the hippocampi of AβO group was significantly reduced, and the microvessels were shrunken and deformed. By contrary, SQYZ administration mitigated those pathological changes. Compared with the sham mice, the expressions of CD31, N-cadherin, PDGFRβ, glial fibrillary acidic protein, phosphorylation of focal adhesion kinase, integrin β1, and integrin α5 in the hippocampi of AβO mice were significantly increased. However, SQYZ administration significantly reduced AβO-induced expression of those proteins. Interestingly, the effect of PDGFRβ inhibitor, sunitinib demonstrated a consistent modulating effect as SQYZ. Finally, the brain-entering components of SQYZ, including ginsenoside Rg5, coptisine, cryptotanshinone, dihydrotanshinone IIA, stigmasterol, and tanshinone IIA had high binding force with PDGFRβ, implicating PDGFRβ as a potential target for SQYZ. ConclusionsOur data indicate that SQYZ improves CBF in AβO-triggered AD-like mice through inhibiting brain pericyte contractility, indicating the treatment potential of SQYZ for AD at the early stage.

A Computational Pipeline to Investigate Longitudinal Blood Flow Changes in the Circle of Willis of Patients with Stable and Growing Aneurysms.

Changes in cerebral blood flow are often associated with the initiation and development of different life-threatening medical conditions including aneurysm rupture and ischemic stroke. Nevertheless, it is not fully clear how haemodynamic changes in time across the Circle of Willis (CoW) are related with intracranial aneurysm (IA) growth. In this work, we introduced a novel reduced-order modelling strategy for the systematic quantification of longitudinal blood flow changes across the whole CoW in patients with stable and unstable/growing aneurysm. Magnetic Resonance Angiography (MRA) images were converted into one-dimensional (1-D) vessel networks through a semi-automated procedure, with a level of geometric reconstruction accuracy controlled by user-dependent parameters. The proposed pipeline was used to systematically analyse longitudinal haemodynamic changes in seven different clinical cases. Our preliminary simulation results indicate that growing aneurysms are not necessarily associated with significant changes in mean flow over time. A concise sensitivity analysis also shed light on which modelling aspects need to be further characterized to have reliable patient-specific predictions. This study poses the basis for investigating how time-dependent changes in the vasculature affect the haemodynamics across the whole CoW in patients with stable and growing aneurysms.

The Water Extract of Rhubarb Prevents Ischemic Stroke by Regulating Gut Bacteria and Metabolic Pathways.

Rhubarb (RR), Chinese name Dahuang, is commonly used in the treatment of ischemic stroke (IS). However, its potential mechanism is not fully elucidated. This study intended to verify the effect of RR on IS and investigate the possible mechanism of RR in preventing IS. IS in male rats was induced by embolic middle cerebral artery occlusion (MCAO) surgery, and drug administration was applied half an hour before surgery. RR dramatically decreased the neurological deficit scores, the cerebral infarct volume, and the cerebral edema rate, and improved the regional cerebral blood flow (rCBF) and histopathological changes in the brain of MCAO rats. The 16S rRNA analysis showed the harmful microbes such as Fournierella and Bilophila were decreased, and the beneficial microbes such as Enterorhabdus, Defluviitaleaceae, Christensenellaceae, and Lachnospira were significantly increased, after RR pretreatment. 1H-nuclear magnetic resonance (1H-NMR) was used to detect serum metabolomics, and RR treatment significantly changed the levels of metabolites such as isoleucine, valine, N6-acetyllysine, methionine, 3-aminoisobutyric acid, N, N-dimethylglycine, propylene glycol, trimethylamine N-oxide, myo-inositol, choline, betaine, lactate, glucose, and lipid, and the enrichment analysis of differential metabolites showed that RR may participate in the regulation of amino acid metabolism and energy metabolism. RR exerts the role of anti-IS via regulating gut bacteria and metabolic pathways.

Effect of Combining Intrauterine Cerebral Blood Flow Changes with Electrical Activity on Prognostic Evaluation of Brain Injury

We sought to investigate the value of combining intrauterine cerebral blood flow changes with brain electrical activity examination in evaluating the prognosis of brain injury. A total of 90 preterm infants were enrolled and divided into two groups: the brain damaged preterm infants group (n=55) and the non-brain damaged preterm infants group (n=35).The diagnostic efficacy of combining intrauterine cerebral blood flow changes with EEG activity examination in predicting the prognosis of preterm infants with brain injury was evaluated usingT-test. Pearson linear correlation was applied to analyze the relationship between fetal intrauterine cerebral blood flow changes combined with electrical activity examination and the prognosis of brain injury. Significant differences were seen in pulse index, S/D ratio, and other indexes between the two groups (P<0.05). The combined approach of intrauterine cerebral blood flow changes with EEG activity examination demonstrated significantly higher values for area under the curve (AUC), sensitivityand negative predictive value compared to using intrauterine cerebral blood flow changes or EEG activity examination alone (P<0.05). A positive correlation was found between fetal intrauterine cerebral blood flow and electrical activity examination (P<0.05). Combining the assessment of intrauterine cerebral blood flow changes with cerebral electrical activity examination proved beneficial in diagnosing the prognosis of brain injury and provided an important reference for early clinical intervention.

Elevation in body temperature may increase susceptibility to cortical spreading depression in a rat model

One characteristic of migraine is recurrent headache attacks, which are known to be induced by changes in climatic variables such as atmospheric pressure, humidity, and outside temperature. However, the relationship between temperature changes and migraine remains unclear. Therefore, we investigated the relationship between body temperature changes and cortical spreading depression (CSD) using KCl-induced rat models of CSD. We initially induced CSD under controlled conditions at a room temperature of 28°C on an operating table maintained at 37°C. Subsequently, we controlled the operating table temperature to induce a second round of CSD under conditions of either a 10 ± 1% increase or decrease in body temperature. We ensured 1hour rest period between the first and second inductions of CSD. The results indicated that the number of CSDs significantly increased after body temperature elevation (8.8 ± 1.2 times before vs. 13.4 ± 1.3 times after, p = 0.0003). The mean percentage change in cerebral blood flow decreased after body temperature increased (before, 33.1 ± 2.4% vs. after, 18.2 ± 1.4%; p = 0.006). There were no significant changes in CSD after body temperature decreased. The susceptibility of the cortex to CSD may increase under conditions of elevated body temperature.

Cerebral Blood Flow Changes and Neuroticism in Late-Life Depression

Cerebral Blood Flow Changes and Neuroticism in Late-Life Depression

Ventilatory Support, Extubation, and Cerebral Perfusion Changes in Pre-Term Neonates: A Near Infrared Spectroscopy Study.

Early extubation is considered to be beneficial for pre-term neonates. On the other hand, premature extubation can cause lung derecruitment, compromised gas exchange, and need for reintubation, which may be associated with severe brain injury caused by sudden cerebral blood flow changes. We used near infrared spectroscopy (NIRS) to investigate changes in cerebral oxygenation (rScO2) and fractional tissue oxygen extraction (+) after extubation in pre-term infants. This is a single-center retrospective study of NIRS data at extubation time of all consecutive pre-term neonates born at our institution over a 1-year period. Comparison between subgroups was performed. Nineteen patients were included; average gestational age (GA) was 29.4 weeks. No significant change was noted in rScO2 and cFTOE after extubation in the whole population. GA and germinal matrix hemorrhage (GMH)-intraventricular hemorrhage (IVH) showed a significant change in rScO2 and cFTOE after extubation. A significant increase in cFTOE was noted in patients with previous GMH-IVH (+0.040; p = 0.05). To conclude, extubation per se was not associated with significant change in cerebral oxygenation and perfusion. Patients with a diagnosed GMH-IVH showed an increase in cFTOE, suggesting perturbation in cerebral perfusion suggesting further understanding during this challenging phenomenon. Larger studies are required to corroborate our findings.

Aerobic fitness as a moderator of acute aerobic exercise effects on executive function.

This study aimed to investigate the moderating role of aerobic fitness on the effect of acute exercise on improving executive function from both behavioral and cerebral aspects. Thirty-four young individuals with motor skills were divided into high- and low-fitness groups based on their maximal oxygen uptake. Both groups completed 30min of moderate-intensity aerobic exercise on a power bike. Executive function tests (Flanker, N-back, More-odd-shifting) were performed before and after exercise and functional near-infrared spectroscopy was used to monitor prefrontal cerebral blood flow changes during the tasks. The results indicated significant differences between the two groups regarding executive function. Participants with lower aerobic fitness performed better than their higher fitness counterparts in inhibitory control and working memory, but not in cognitive flexibility. This finding suggests that the aerobic fitness may moderate the extent of cognitive benefits gained from acute aerobic exercise. Furthermore, the neuroimaging data indicated negative activation in the frontopolar area and dorsolateral prefrontal cortex in response to three complex tasks. These findings underscore the importance of considering individual aerobic fitness when assessing the cognitive benefits of exercise and could have significant implications for tailoring fitness programs to enhance cognitive performance.

DYNAMIC ASSESSMENT OF CEREBRAL PERFUSION BLOOD FLOW IN THE EARLY POST-STROKE PERIOD ACCORDING TO NON-CONTRAST MRI DATA

HighlightsThe non-contrast perfusion MR sequence pCASL (pseudocontinuous arterial spin labeling) is a technique that allows specialist to quantify and trace the changes in cerebral blood flow in the early post-stroke period. At the same time, there is a change in perfusion indices not only in the ischemic stroke area, but also in visually intact areas of the ipsilateral and contralateral hemispheres of the brain, which indicates the involvement of the blood supply area and the brain as a whole in the pathological process. The obtained data on the dynamics in perfusion, verified by the results of cognitive tests, open up the prospect of a comprehensive study of stroke as a complex brain disease with the possibility of predictive assessment of rehabilitation. Aim. To assess the dynamics of microcirculatory changes in the brain in the early post-stroke period by non-contrast perfusion MRI.Methods. The study included 42 patients with acute ischemic stroke. The patients were examined by 3T MRI using the following sequences: DWI-EPI, 3D FLAIR-SPIR, T2-TSE, T1W 3D-TFE, and pseudocontinuous arterial spin labeling (pCASL) on 1–3 days, 7–10 days and 3 months later after the manifestation of acute ischemic stroke. The cerebral blood flow (CBF) was obtained in 4 supratentorial regions of the brain: in the ischemic stroke and contralateral areas, as well as in a visually intact area of the ipsilateral and contralateral hemispheres (mL/100g/min).Results. In the ischemic stroke area, CBF increased from 19.86±5.69 (mean+Std) to 27.57±4.86 by first to the second examination, which was associated with the infusion therapy, local inflammatory response and compensatory reperfusion. By the 3rd examination CBF decreased to 14.48±3.66 (Student t-test, p&lt;0.05), which reflects cystic and atrophic transformation of the affected area. In visually intact white matter of the ipsilateral and contralateral hemispheres, CBF increased from hypoperfused to normoperfused from the first to the third examination. There was a significant decrease (p&lt;0.001) in tissue blood flow (by 54% for the 1st, 38% for the 2nd, 67% for the 3rd examination) in the ischemia area relative to intact parts of the brain.Conclusion. The pCASL allowed us to assess CBF in the post-stroke period in the ischemic area and in visually intact area, nevertheless, it requires additional pre- and postprocessing of data to obtain quantitative values. At the same time, we observed changes in perfusion in the ischemic stroke area, and in the visually intact areas of the ipsilateral and contralateral hemispheres of the brain, indicating the involvement of the cerebral blood flow and brain as a whole in the pathological process.

Correlation of cerebral blood flow velocity with haematocrit in neonates at risk of polycythaemia: a COHORT study

Background: The incidence of polycythemia is 1.5-4% of all live births. To diagnose polycythemia, a venous hematocrit is necessary, and polycythaemia is linked to changes in cerebral blood flow. The primary objective is to compare cerebral blood flow velocity (CBFV) and resistance index (RI) between polycythemia and normocythemia groups. The secondary objective is to correlate the peak systolic velocity (PSV) of anterior and middle cerebral arteries (ACA and MCA) with hematocrit in neonates at risk for polycythemia. Methods: In a prospective observational study, babies with a gestational age of &gt;35 weeks and a risk factor for polycythaemia were enrolled in the study. Free-flowing venous blood was sent for haematocrit measurement between 2 and 6 hours of life. Repeat PCV is sent to babies with a prior value of PCV &gt;65% at 36 hours of life or before discharge. PSV, end diastolic velocity (EDV), RI of ACA and MCA were measured using Mindray portable ultrasound machine with a mini- curved ultrasound transducer (8-13 mhz). Data is entered in excel and analysed. Results: Out of 75 enrolled babies, 19 had polycythaemia. The mean PSV±SD of MCA was 27.84±6.04 cm/s and 27.27±5.74 cm/s in the normocythemia and polycythemia groups, respectively, at 6 hours of life, which is statistically insignificant. The mean PSV±SD of MCA was 31.41±6.92 cm/s and 29.61±6.57 cm/s in normocythemia and polycythaemia groups, respectively, at 36 hours of life, which is statistically insignificant too. Conclusions: Cerebral Doppler values did not correlate with haematocrit between the normocythemia and polycythemia groups in the neonates at risk of polycythemia.