Cerebral Blood Flow Parameters Research Articles

A new method of intraoperative assessment of the dynamics of cortical blood flow using imaging photoplethysmography

Background. Intraoperative assessment of changes in cerebral blood flow is an important component of objective quality control of surgical treatment of cerebral artery aneurysms. Various techniques have been tried to solve this task, but they all have their drawbacks, which forces us to look for new ways of blood flow monitoring. We propose to use the technology of imaging photoplethysmography (IPPG) – a technically simple, contactless, safe and cheap optical method for assessing the perfusion of biological tissues.Aim. To demonstrate the possibility of using IPPG to assess the dynamics of cerebral blood flow parameters during aneurysm clipping surgery, as well as to identify early changes in blood supply to the cerebral cortex.Materials and methods. The study was carried out during six surgeries of clipping aneurysms of the anterior part of the Willis’s circle, both in the acute stage of rupture (n = 1) and in a planned manner (n = 5). The IPPG system, which is an LED illuminator in a single unit with a digital video camera, was located on a tripod 25 cm from the intervention zone. During each operation, two one-minute recordings of the illuminated surface of the cerebral cortex were performed: after dissection of the dura mater and before its suturing at the end of the main stage of the intervention. To improve the measurement accuracy, video frames of the studied area were recorded synchronously with the registration of an electrocardiogram. After recording, two IPPG parameters were calculated and compared: the amplitude of the pulsatile component and the pulse wave transit time. Thereafter, the obtained data were compared with the results of computed tomography. Statistical analysis was performed using pairwise comparison tests in the GraphPad Prism software package.Results. Clipping of cerebral vessel aneurysms are accompanied by significant changes in the parameters of cerebral blood flow. Analysis of the data for all patients revealed significant differences in IPPG parameters before and after surgery, namely, statistically significant increase in amplitude of the pulsatile component (n = 3) and decrease in pulse wave transit time (n = 5). The absence of significant changes in both parameters was found only in one patient who had mechanical damage in the cortex in the region of video recording.Conclusion. The IPPG system is capable to quantify changes in blood supply to the cortex during surgical treatment of cerebral artery aneurysms and to identify areas with either increased or decreased blood supply. In-depth studies are required to obtain additional markers of the postoperative state of cerebral blood flow.

A novel noninvasive method for dynamic cerebral autoregulation monitoring based on near-field coupling

Dynamical cerebral autoregulation (dCA) is crucial for optimizing blood pressure (BP) management and enhancing the prognosis of stroke patients. This study aims to obtain detailed cerebral blood flow (CBF) based on near-field coupling (NFC) and establish a novel method for evaluating dCA comprehensively. We developed a synchronized monitoring system of photoplethysmography-based mean arterial pressure (MAP) and NFC-based CBF. Fifteen healthy volunteers underwent dCA measurements before and after a body tilt. The multiple CBF parameters derived from NFC, along with synchronized MAP data, were used to compute the new dCA indices. Through a comparative analysis with TCD and NIRS, we studied the ability of NFC to assess dCA accurately and comprehensively. The results show that the trend in CBF changes measured by NFC before and after body tilt corresponded to the fluctuations observed in MAP. Compared to CBFV from TCD and rSO2 from NIRS, the NFC-derived parameters provide both intracranial hemodynamics and microcirculation. The dCA indices from NFC show high consistency with those from TCD, and the RFx-PVD, RFx-VEI, and RFx-HFC are the ideal indices for assessing dCA. The CAT of RFx-HFC has the largest effect size in distinguishing different dCA levels. These results demonstrate the feasibility and reliability of integrating NFC with synchronized MAP data collection to comprehensively and accurately assess dCA. It is expected to overcome the mutual constraints of existing methods in terms of time resolution, detection range and depth, and provide a new solution for continuous bedside assessment of dCA in patients with stroke.

Model-predicted brain temperature computational imaging by multimodal noninvasive functional neuromonitoring of cerebral oxygen metabolism and hemodynamics: MRI-derived and clinical validation.

Brain temperature, a crucial yet under-researched neurophysiological parameter, is governed by the equilibrium between cerebral oxygen metabolism and hemodynamics. Therapeutic hypothermia has been demonstrated as an effective intervention for acute brain injuries, enhancing survival rates and prognosis. The success of this treatment hinges on the precise regulation of brain temperature. However, the absence of comprehensive brain temperature monitoring methods during therapy, combined with a limited understanding of human brain heat transmission mechanisms, significantly hampers the advancement of hypothermia-based neuroprotective therapies. Leveraging the principles of bioheat transfer and MRI technology, this study conducted quantitative analyses of brain heat transfer during mild hypothermia therapy. Utilizing MRI, we reconstructed brain structures, estimated cerebral blood flow and oxygen consumption parameters, and developed a brain temperature calculation model founded on bioheat transfer theory. Employing computational cerebral hemodynamic simulation analysis, we established an intracranial arterial fluid dynamics model to predict brain temperature variations across different therapeutic hypothermia modalities. We introduce a noninvasive, spatially resolved, and optimized mathematical bio-heat model that synergizes model-predicted and MRI-derived data for brain temperature prediction and imaging. Our findings reveal that the brain temperature images generated by our model reflect distinct spatial variations across individual participants, aligning with experimentally observed temperatures.

The impact of diffusion and perfusion-weighted imaging on glioma grading

Abstract Objectives Determining the grade of a glioma is extremely important for treatment planning and prognosis prediction. The study aimed to evaluate the usefulness of multiparametric perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) in preoperative glioma grading. Methods In this retrospective study, 63 individuals with brain tumors histologically confirmed, of which 23 had low-grade gliomas (LGGs) and 40 had high-grade gliomas (HGGs) were involved. We conducted this paper on apparent diffusion coefficient (ADC) maps using the entire tumor volume method, allowing us to use all ADC values of the tumor. Small-sample regions of interest (ROIs) were drawn to collect parameters of relative cerebral blood flow (rCBF), cerebral blood flow (CBF), and relative cerebral blood volume (rCBV), from both the tumor core and peritumoral edema. The PWI and DWI metrics were compared to identify the most accurate distinguishing HGGs and LGGs, analyze receiver operating characteristics (ROC), and evaluate the diagnostic performance using solitary parameters and combined. Results In diffusion MRI, there were significant differences in minimum ADC and mean ADC between LGGs and HGGs (p<0.05), with the larger area under the curve (AUC) of 0.898 found for mean ADC at a cut-off value of 1.275, with sensitivity of 82.6 % and specificity of 90 %. The maximum ADC value did not differ significantly (p>0.05). All perfusion parameters in both the tumor core and peritumoral edema area were significantly greater values in cases of HGG compared to LGG (p<0.001), with the highest AUC of 0.946 found for solid tumor rCBV value (rCBVt), the cut-off is 3.585, sensitivity of 85 % and specificity of 100 %. Combining mean ADC and rCBVt provided an excellent AUC of 0.975, a sensitivity of 92.5 %, and a specificity of 91.3 % for differentiating between HGGs and LGGs. Conclusions Perfusion and diffusion MRI are valuable in discriminating between high-grade and low-grade gliomas, with the major criterion in the decision-making process being the combined mean ADC and rCBVt parameters.

Prognostic value of resistive index (measured in anterior cerebral artery) in term neonates with hypoxic ischemic encephalopathy

Background: Perinatal asphyxia refers to a condition during the first and second stage of labor and soon after birth in which impaired gas exchange leads to acidosis, hypoxemia, and hypercarbia. The Doppler technique is a non-invasive method that can be used at the bed side without disturbing patients, for risk of subsequent neurodevelopment impairment in HIE. It has been proven that impaired cerebral circulation plays the main role in the pathogenesis of hypoxic ischemic brain injury in neonates. Methods: Doppler sonography conducted in all enrolled subjects. Cerebral blood flow parameters-peak systolic velocity, end diastolic velocity and resistive index were measured in anterior cerebral artery bilaterally on parasagittal planes obtaining the images through the anterior fontanelle with in first 72 hours. Results: In our study we found that death during hospital stay in neonates with normal RI and abnormal RI is 13% and 28.6% respectively (p<0.01). Abnormal neurological outcome of 70.6% at 6 months and 64.7% at 12 months in patients with abnormal RI and 23.3% at 6 months and 18.6% at 12 months in patients with normal RI (p<0.01). Conclusions: There is a significant correlation between neurodevelopmental disabilities and cerebral blood flow parameters in neonates with hypoxic ischemic encephalopathy. Detection of increased or decreased in cerebral blood flow velocities in neonates with in first 72 hours postpartum has a significant prognostic value related to death and long-term neurodevelopmental outcome.

Functional transcranial dopplerography is a diagnostic tool for cognitive impairment syndrome

Functional transcranial dopplerography (FTCD) is a non-invasive ultrasound examination that allows recording the dynamics of cerebral blood flow parameters under conditions of factors stimulated the activity of the structures of the central nervous system. Judgments about the sensitivity and specificity of FTCD are based on the close connection between changes in the activity of the nervous (somatic) system and the response of regional cerebral blood flow (CBF). The technique is a portable and accessible diagnostic method used in assessing the possibility of expanding functional activity during the recovery period after a stroke. An increase in mental activity in response to the presentation of a cognitive task, accompanied by an increase in glucose and oxygen consumption and naturally requiring an increase in cerebral perfusion parameters, can also be assessed by changes in regional blood flow parameters while maintaining the reactive mechanisms of autoregulation. A search of literature sources was carried out in the electronic databases PubMed and Scopus. For the subject search, Medical Subject Headings were used. A total of 36 sources that mentioned the terms «cognitive function» and «functional transcranial Doppler» were selected for preliminary analysis. At the present stage, methodological problems are obvious, requiring the development and implementation of a standard package of targeted functional tests to assess cognitive status. Available equipment and software require technological solutions to ensure objective recording of changes in cerebral blood flow during testing and training.

Associations between ASL‐derived cerebrovascular health and cognitive performance: results from the Insight 46 study

AbstractBackgroundCardiovascular and cerebrovascular pathology may accelerate brain aging and cognitive decline. Structural cerebrovascular imaging biomarkers, such as white matter hyperintensities, reflect mostly irreversible accumulated damage. In contrast, cerebral blood flow (CBF), measured with arterial spin labelling (ASL) perfusion MRI, is a potential early haemodynamic biomarker of cognitive impairment. However, our understanding of physiological CBF variability and its relation with cognition is limited.MethodWe included 245 cognitively unimpaired participants from the Insight 46 birth cohort study, who underwent 3D T1‐weighted and pseudo‐continuous ASL‐MRI (labelling duration = 1800ms; post‐labelling delay = 1800ms) on a 3T Siemens Biograph mMR PET‐MRI scanner. Cognitive assessment included tests for logical memory (Wechsler Memory Scale‐Revised), associative memory (Face‐Name Associative Memory Exam), attention and processing speed (Digit‐symbol substitution and response inhibition test), non‐verbal reasoning (Matrix test), executive functioning (Choice Reaction Time), visuomotor integration (circle‐tracing task), and two composite scores (Mini‐Mental State Examination (MMSE) and the Preclinical Alzheimer Cognitive Composite).ResultSample characteristics are reported in Table 1. Associations were found between GM sCoV and MMSE (Male/Female ß = 0.74/‐0.75, p = 0.028, Figure 1), and GM sCoV and Logical Memory (Male/Female ß = 1.05/‐0.25, p = 0.005, Figure 2), but not between CBF and any cognitive scores (p>0.05).ConclusionIn a cognitively unimpaired population, cognitive performance was associated with GM sCoV but not with other CBF parameters. However, in males, the relationship was opposite to what we expected. Further work should investigate to what extent this indicates macrovascular change occurs before perfusion alterations and could relate to future cognitive decline, and how they differ between sex.

The role of blood pressure variability indicators combined with cerebral blood flow parameters in predicting intraventricular hemorrhage in very low birth weight preterm infants.

Hemodynamic instability is the main factor responsible for the development of intraventricular hemorrhage (IVH) in premature newborns. Herein, we evaluated the predictive ability of blood pressure variability (BPV) and anterior cerebral artery (ACA) blood flow parameters in IVH in premature infants with gestational age (GA) ≤32 weeks and birth weight (BW) ≤ 1,500 g. Preterm infants with GA ≤32 weeks and BW ≤ 1,500 g admitted to the neonatal intensive care unit (NICU) of the hospital affiliated to Yangzhou University from January 2020 to January 2023 were selected as the research subjects. All preterm infants were admitted within 1 h after birth, and systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial blood pressure (MABP) were monitored at 1-h intervals. The difference between maximum and minimum values (max-min), standard deviation (SD), coefficient of variation (CV), and successive variation (SV) were used as BPV indicators. On the 1st, 3rd, and 7th day after birth, transcranial ultrasound examination was performed to screen for the occurrence of IVH. On the 24 ± 1 h after birth, systolic velocity (Vs), diastolic velocity (Vd), and resistance index (RI) of the ACA were measured simultaneously. Preterm infants were divided into the IVH group and non-IVH group based on the results of transcranial ultrasound examination, and the correlation between BPV indicators, ACA blood flow parameters, and development of IVH was analyzed. A total of 92 premature infants were enrolled, including 49 in the IVH group and 43 in the non-IVH group. There was no statistically significant difference in baseline characteristics such as BW, GA, sex, and perinatal medical history between the two groups of preterm infants (P > 0.05). The SBP SD (OR: 1.480, 95%CI: 1.020-2.147) and ACA-RI (OR: 3.027, 95%CI: 2.769-3.591) were independent risk factors for IVH in premature newborns. The sensitivity and specificity of combined detection of SBP SD and ACA-RI in predicting IVH were 61.2% and 79.1%, respectively. High BPV and ACA-RI are related to IVH in premature infants with GA ≤32 w and BW ≤1,500 g. Combined detection of SBP SD and ACA-RI has a certain predictive effect on early identification of IVH.

Three-Dimensional Arterial Spin Labeling for the Evaluation of the Cerebral Hemodynamics in Ischemic and Hemorrhagic Moyamoya Disease

Introduction: Moyamoya disease (MMD) is a vascular disease with significant risk of mortality due to ischemia or hemorrhage in the brain. The goal of the study was to explore three-dimensional arterial spin labeling (3D-ASL) to improve evaluation of cerebral hemodynamics in patients with MMD. Methods: Our study included 54 cases of ischemic MMD and 42 cases of hemorrhagic MMD. Dynamic susceptibility contrast-enhanced perfusion-weighted imaging (DSC-PWI) and 3D-ASL were performed at 3.0 T. Based on these scans, cerebral blood flow (CBF), mean transit time (MTT), and time to peak (TTP) were calculated and compared between patients with different disease subtypes. Receiver operating characteristics analysis was used to assess the diagnostic sensitivity and specificity of different imaging procedures and parameters. Results: Our data suggested that CBF in the lesion area was more severely reduced in patients with hemorrhagic MMD than in those with ischemic MMD. The CBF parameter in 3D-ASL diagnosed hemorrhagic and ischemic MMD with a significant sensitivity and specificity of 80.59% and 57.41%, respectively, with an area under the curve (AUC) of 0.75. We also found that the relative CBF of 3D-ASL was more pronounced decreased and the relative MTT and TTP of DSC-PWI were significantly increased in patients with hemorrhagic MMD than those with ischemic MMD. Specificity and sensitivity and AUC of 3D-ASL were better than the comparison of absolute values from DSC-PWI scans. Conclusion: Our study indicated that 3D-ASL is powerful in differentiating patients with cerebral ischemic or hemorrhagic MMD, providing another diagnostic tool that could potentially improve precision medicine to monitoring MMD patients.

Investigation of tissue perfusion of the brain in patients with large and giant tumors of the bridge-cerebellar angle

The article presents the results of the study of pons and cerebellar tissue perfusion in patients with large and giant cerebellopontine angle tumors. Perfusion computed tomography was performed in 10 patients with vestibular schwannomas and 8 patients with temporal bone meningiomas. The parameters of cerebral blood flow were calculated in 6 regions of interest in the area of the pons and the cerebellar hemispheres. There are manifestations of brain tissue hypoperfusion in the pons and hyperemia in the nearby parts of the cerebellar hemisphere. The revealed changes indicate the possibility of disorders of local cerebral blood flow after surgery.

Features of Changes in the Velocity Indicators of Cerebral Blood Flow in Rats at Different Stages of Aging

Changes in the velocity of cerebral blood flow can make a significant contribution to the formation of age-related cerebrovascular diseases. The age-related changes in the velocity indicators of cerebral blood flow in rats at different stages of aging were studied. Using Doppler ultrasound the state of blood flow in the cortex and subcortical structures of the cerebral hemispheres was analyzed by the value of linear velocities and blood flow indexes in young Sprague-Dawley 4-month-old and aging 18 and 23-month-old rats. It has been established that aging is accompanied by changes in the parameters of cerebral blood flow in the cortex and subcortical structures of the rat brain. Changes develop gradually and differ at different stages of aging. By 18 months, perfusion in the frontal and parietal regions hemispheres of the brain increases due to an increase in peak and mean velocity per cardiac cycle and a decrease in the level of resistance of cerebral vessels. These processes precede the development of subsequent hypoperfusion disorders of blood flow observed at later stages of aging. Hypoperfusion changes in 23-month-old rats are most pronounced in the frontal region of the cerebral hemispheres and are characterized by a decrease in peak velocities and an increase in blood flow indexes.

Regional cerebral blood flow and brain atrophy in mild cognitive impairment and Alzheimer's disease.

A decline in the regional cerebral blood flow (CBF) is proposed to be one of the initial changes in the Alzheimer's disease process. To date, there are limited data on the correlation between CBF decline and gray matter atrophy in mild cognitive impairment (MCI) and AD patients. to investigate the association between CBF with the gray matter structural parameters such as cortical volume, surface area, and thickness in AD, MCI, and healthy controls (HC). Data from three groups of participants including 39 HC, 82 MCI, and 28 AD subjects were obtained from the Alzheimer's disease Neuroimaging Initiative (ADNI). One-way ANOVA and linear regression were used to compare data and find a correlation between structural parameters such as cortical volume, surface area, and thickness and CBF which measured by arterial spin labeling (ASL)-MRI. Our findings revealed a widespread significant correlation between the CBF and structural parameters in temporal, frontal, parietal, occipital, precentral gyrus, pericalcarine cortex, entorhinal cortex, supramarginal gyrus, fusiform, precuneus, and pallidum. CBF decline may be a useful biomarker for MCI and AD and accurately reflect the structural changes related to AD. According to the present results, CBF decline, as measured by ASL-MRI, is correlated with lower measures of structural parameters in AD responsible regions. It means that CBF decline may reflect AD-associated atrophy across disease progression and is also used as an early biomarker for AD and MCI diagnosis.

470 Robotic Transcranial Doppler With Artificial Intelligence for Real-Time Intraoperative Neuromonitoring During Endovascular Carotid Revascularization – A Novel and Autonomous Neuromonitoring Tool

INTRODUCTION: Real-time intraoperative neuromonitoring is crucial to account for cerebral blood flow and embolic protection offered by proximal and distal cerebral protection devices during carotid revascularization procedures. METHODS: All patients diagnosed with high-grade carotid stenosis were prospectively enrolled between October 2021 thru February 2022. The TCD Robot head-brace system was used to secure the patients head, and the robot calibrated to automatically identify ipsilateral MCA or the terminal ICA. Patient demographics and procedural characteristics relevant to the robotic system such as signal strength, time to find signal, intracranial depth of the relevant vessel, cerebral waveform, and emboli count were recorded for the 4 critical phases: i- Access to crossing the lesion, ii- Filter and balloon deployment, iii- Stent placement and implantation, and iv- Removal of delivery system. RESULTS: Eight patients were included in our study (6 males [75%]; mean age 71.5 ± 3.9). Six out of 8 patients were symptomatic with a mean diameter stenosis of 83.5 ± 4.1. Average time taken to find a stable signal was 62 seconds (Range: 10-122). Terminal ICA was the vessel identified in all cases with a mean depth of 64mm (Range: 59-71). Flow arrest was demonstrated in all cases with flow reversal demonstrated in 2. Mean duration for the TCD Robotic surveillance was 23.6 ± 0.9 minutes with an average of 117 distal emboli (Range: 45-143) recorded by the device. Linear regression model identified stent placement and implantation as statistically significant (P = 0.0419) contributor to the final emboli count. CONCLUSIONS: To our knowledge, this is the first case series of real-time comprehensive neuromonitoring using a Robotic Transcranial Doppler system with Artificial Intelligence demonstrating various cerebral blood flow parameters including flow arrest and distal embolic incidence intra-operatively.

Changes in cerebral blood flow parameters among preterm 30–34 week neonates who are initiated on kangaroo mother care - A prospective analytical observational study

BackgroundKangaroo mother care (KMC) is recommended standard of care for preterm neonates. They are vulnerable for cerebral blood flow (CBF) fluctuations linked to intraventricular hemorrhage and periventricular leukomalacia, which have implications on neurodevelopment. This study was designed to document any change in CBF in middle cerebral artery (MCA) of stabilized preterm 30–34 weeks neonates who are initiated on KMC. MethodsWe designed a prospective analytical observational study in a tertiary care neonatal unit. We enrolled 30–34 weeks preterm neonates eligible for KMC after their stabilization (n = 40). CBF was measured in supine position via right MCA Doppler through the temporal window before any KMC, after 2 h of 1st KMC session and following 24 h of 1st session. CBF was quantified in terms of pulsatility index (PI), Resistive Index (RI), peak systolic velocity (PSV), end-diastolic velocity (EDV), mean velocity (MV) and values were compared against the existing normative values. ResultsMean gestation of study population was 31.91 weeks with a mean birth weight of 1432.75 g. Median day of initiation of KMC was 7 days with mean duration of KMC on day 1 was 4.56 h. We could find statistically significant decrease in the values of PI and RI from 90th centile towards 50th centile of normative values with a mean difference of 0.22 (99 % CI 0.02–0.43, p 0.005) for PI and 0.05 (99 % CI 0.02–0.07, p = 0.000) for RI post the first session of KMC. Following 24 h of 1st KMC session, we could find a significant increase in values of PSV, EDV and MV comparing values of pre-initiation with day 2 pre-KMC but values of PI and RI were not significantly different. ConclusionCBF among 30–34 week preterm neonates tend to optimize after initiation of KMC.

Wild blueberry (poly)phenols can improve vascular function and cognitive performance in healthy older individuals: a double-blind randomized controlled trial

BackgroundEvidence suggests that the intake of blueberry (poly)phenols is associated with improvements in vascular function and cognitive performance. Whether these cognitive effects are linked to increases in cerebral and vascular blood flow or changes in the gut microbiota is currently unknown. MethodsA double-blind, parallel randomized controlled trial was conducted in 61 healthy older individuals aged 65–80 y. Participants received either 26 g of freeze-dried wild blueberry (WBB) powder (302 mg anthocyanins) or a matched placebo (0 mg anthocyanins). Endothelial function measured by flow-mediated dilation (FMD), cognitive function, arterial stiffness, blood pressure (BP), cerebral blood flow (CBF), gut microbiome, and blood parameters were measured at baseline and 12 wk following daily consumption. Plasma and urinary (poly)phenol metabolites were analyzed using microelution solid-phase extraction coupled with liquid chromatography–mass spectrometry. ResultsA significant increase in FMD and reduction in 24 h ambulatory systolic BP were found in the WBB group compared with the placebo group (0.86%; 95% CI: 0.56, 1.17, P < 0.001; −3.59 mmHg; 95% CI: −6.95, −0.23, P = 0.037; respectively). Enhanced immediate recall on the auditory verbal learning task, alongside better accuracy on a task-switch task was also found following WBB treatment compared with placebo (P < 0.05). Total 24 h urinary (poly)phenol excretion increased significantly in the WBB group compared with placebo. No changes in the CBF or gut microbiota composition were found. ConclusionsDaily intake of WBB powder, equivalent to 178 g fresh weight, improves vascular and cognitive function and decreases 24 h ambulatory systolic BP in healthy older individuals. This suggests that WBB (poly)phenols may reduce future CVD risk in an older population and may improve episodic memory processes and executive functioning in older adults at risk for cognitive decline.Clinical Trial Registration number in clinicaltrials.gov: NCT04084457.

Association between the results of neuropsychological testing and indicators of regional cerebral blood flow according to SPECT data of cardiac surgical patient

Highlights. The article provides new data on the association between changes in regional cerebral blood flow during SPECT and cognitive impairment in patients who underwent coronary artery bypass grafting and combined carotid endarterectomy and coronary artery bypass grafting with cardiopulmonary bypass. The possibilities of using SPECT as a diagnostic tool in localization of areas with a similar association, in assessing the dynamics in brain perfusion and cognitive functions in the pre- and postoperative period are shown.Aim. To determine the presence of an association between the indicators of regional cerebral blood flow according to single-photon emission computed tomography (SPECT) data and the data of neuropsychological testing in cardiac surgery patients.Methods. We studied the parameters of regional cerebral blood flow (rCBF) and the data of neuropsychological testing in 34 cardiac surgical patients who underwent coronary artery bypass grafting (CABG, n = 13) and combined carotid endarterectomy and CABG (n = 21). The state of the brain was assessed by SPECT using a radiopharmaceutical 99mTc-HMPAO (Ceretek). Assessment of cognitive functions before surgery, 2–3 days before, and in the early postoperative period, on days 5–7, was carried out using a hardware-software complex Status-PF.Results. A statistically significant relationship was found between the indices of rCBF according to neuropsychological testing data in the pre- and postoperative period. We noted a moderate correlation with the Beck Depression Scale indicators in the 1st (p = 0.010943) and 2nd (p = 0.000604) groups before surgery. There was a high correlation with visual-motor response time (VMR) before (p = 0.003878) and after the procedure (p = 0.001251), a moderate correlation with the number of errors (VMR) before the procedure (p = 0.042911) and a high correlation after the procedure (p = 0.003521) in the 1st group; in the 2nd group, there was a moderate correlation before (p = 0.004625) and after the procedure (p = 0 .005689). A moderate correlation with the indicators of attention after the procedure (p = 0.049611) was noted in the 1st group, in the 2nd group, we noted a moderate correlation before (p = 0.021969) and after the procedure (p = 0.008905). In the 2nd group there was a moderate correlation with the number of processed symbols (the Bourdon test) during the 1st minute before the procedure (p = 0.016491), a high correlation after the procedure (p = 0.007920), and a high correlation with the number of processed symbols during the 4th minute before the procedure (p = 0.001473). There was a moderate correlation with a total with number of processed symbols in the 2nd group before (p = 0.029073) and after the procedure (p = 0.024164), and a high correlation with the number of errors made after the procedure in the 1st (p = 0.006367) and 2nd (p = 0.013780) groups. A high correlation with indicators of attention after surgery (p = 0.000153) was noted as wellConclusion. The indicators of regional cerebral blood flow obtained by SPECT in patients undergoing isolated CABG and combined CAE and CABG were associated with the data of neuropsychological testing and reflect changes in the cognitive status of patients.

Superficial temporal artery-middle cerebral artery bypass in combination with encephalo-myo-synangiosis in Chinese adult patients with moyamoya disease.

To evaluate the feasibility and safety of superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis in combination with encephalo-myo-synangiosis (EMS) in Chinese adult patients with moyamoya disease (MMD). A total of 65 patients with MMD who underwent combined STA-MCA bypass + EMS surgical revascularisation were included in this study. Each patient had a follow-up visit 6 months after discharge. Early bypass function was evaluated via computed tomography angiography and digital subtraction angiography, which were performed preoperatively and at 6 months after surgery. The perfusion parameters of cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT) and time to peak (TTP) were obtained and analysed. The clinical status of each patient was evaluated using a modified Rankin scale (mRS) preoperatively and at 1 week and 6 months after surgery. Among the 65 enrolled patients, postoperative complications were observed in 5 (7.69%) patients, with 2 cases of dysphasia, 2 cases of new cerebral infarction and 1 case of seizure. Six months after surgery, 66 out of 68 hemispheres were found to have a functioning extra-intracranial bypass, and the patency rate was 97.06%. In terms of CBF perfusion, both the CBF and CBV increased significantly, while the MTT and TTP decreased after surgery. The mRS scores measured 1 week and 6months after surgery were much lower than those measured preoperatively. A direct STA-MCA bypass procedure in combination with indirect EMS bypass is feasible and safe for Chinese adult patients with MMD.

Intravoxel incoherent motion and diffusion kurtosis imaging at 3T MRI: Application to ischemic stroke

Background and purposeThe DKI-IVIM model that incorporates DKI (diffusional kurtosis imaging) into the IVIM (Intravoxel Incoherent Motion) concept was investigated to assess its utility for both enhanced diffusion characterization and perfusion measurements in ischemic stroke at 3 T. MethodsFifteen stroke patients (71 ± 11 years old) were enrolled and DKI-IVIM analysis was performed using 9 b-values from 0 to 1500 s/mm2 chosen with the Cramer-Rao-Lower-Bound optimization approach. Pseudo-diffusion coefficient D*, perfusion fraction f, blood flow-related parameter fD*, the diffusion coefficient D and an additional parameter, the kurtosis, K were determined in the ischemic lesion and controlateral normal tissue based on a region of interest approach. The apparent diffusion coefficient (ADC) and arterial spin labelling (ASL) cerebral blood flow (CBF) parameters were also assessed and parametric maps were obtained for all parameters. ResultsSignificant differences were observed for all diffusion parameters with a significant decrease for D (p < 0.0001), ADC (p < 0.0001), and a significant increase for K (p < 0.0001) in the ischemic lesions of all patients. f decreased significantly in these regions (p = 0.0002). The fD* increase was not significant (p = 0.56). The same significant differences were found with a motion correction except for fD* (p = 0.47). CBF significantly decreased in the lesions. ADC was significantly positively correlated with D (p < 0.0001) and negatively with K (p = 0.0002); K was also negatively significantly correlated with D (p = 0.01). ConclusionsDKI-IVIM model enables for simultaneous cerebral perfusion and enhanced diffusion characterization in an acceptable clinically acquisition time for the ischemic stroke diagnosis with the additional kurtosis factor estimation, that may better reflect the microstructure heterogeneity.

Cerebral monitoring of very preterm infants with anterior cerebral artery resistive index and early NIRS.

The prediction of adverse conditions in the preterm neonatal brain might be improved by cerebral monitoring using combined measures of cerebral function, including oxygenation and blood flow parameters. To perform the consecutive measurements of the resistive index (RI) from the anterior cerebral artery (ACA) within the first week of life and to evaluate the association of these measurements with cerebral oxygen saturation (Csat) detected by near-infrared spectroscopy (NIRS). This prospective cohort study enrolled very preterm infants, <32 weeks of gestational age, admitted to a tertiary neonatal intensive care unit. Csat levels were continuously monitored using NIRS for 72 h after birth. ACA RI measurements were obtained on the first, third, and seventh days of life by using transcranial Doppler ultrasound. These measurements were also compared between infants with and without unfavorable outcomes, including severe intraventricular hemorrhage (IVH) and early mortality. A total of 96 preterm infants with Csat and ACA RI measurements were analyzed. Age at birth was 28.3 ± 1.9 weeks and birth weight was 1090 ± 305 g. The mean Csat of the infants was 77.1% ± 8.2% during the first 72 h of life. Mean ACA RI values were 0.76 ± 0.10, 0.75 ± 0.08, and 0.77 ± 0.08 on the first, third, and seventh days of life, respectively. RI on the first day of life was significantly higher in infants delivered by cesarian section than in those delivered vaginally (0.77 vs. 0.69; p = 0.017). Infants who died earlier had significantly higher ACA RI values on the first day than infants who survived beyond the first 7 postnatal days (0.83 vs. 0.76; p < 0.001). There was no association between ACA RI and Csat in the early period of life. ACA RI values on the first postnatal day might be significant for predicting early mortality in very preterm infants.

Brain computed tomography perfusion analysis in HIV-seropositive adults with and without neurocognitive impairment in Nigeria: outcomes and challenges of a pilot study.

the significance of cerebrovascular disease in HIV-associated neurocognitive disorder (HAND) in a homogeneous black population has not yet been determined. This incident case-control study used CT perfusion imaging to quantify and compare regional cerebral blood flow parameters in neuro-cognitively impaired and unimpaired HIV+ participants of the Ibadan Cohort on Neuro AIDS (ICON) in Nigeria. this was an incident case-control study consisting of twenty-seven HIV+ adults, classified based on Frascati criteria into neurocognitive impaired (n=18) and unimpaired (n=9) groups, who had brain computed tomographic perfusion (CTP) with a 64-slice Toshiba T scanner. The standard deviation (SD) of regional mean transit time (MTT), cerebral blood flow (CBF), and cerebral blood volume (CBV) values were calculated for bilateral basal ganglia (BG), frontal, parietal, temporal, and occipital regions from CT perfusion maps. The regional mean values and variability (SD) in the CTP measures were compared in the groups using an independent student t-test. differentially higher variability in the bilateral CBF measures in the parietal (right; OR = 1.14, x̄ =5.61, p=0.041, CI=0.27-11.35/left; OR = 1.16, x̄=7.01, p=0.03, CI=5.6-13.47) and time to peak (TTP) measures in the basal ganglia (right; OR = 3.78, x̄=0.88, p=0.032, CI=0.081-1.67/left; OR = 2.44, x̄=1.48, p=0.020, CI=0.26-2.71) and occipital (right; OR = 2.18, x̄=1.32, p=0.018, CI=0.25-2.38/left; OR = 1.93, x̄=1.08, p=0.034, CI=0.086-2.06) regions were observed in the cognitively impaired group compared to the unimpaired group. the study evidence suggests that alterations in cerebral perfusion implicated in HIV-associated neurocognitive disorder may be possibly demonstrated using CTP, a readily available resource in most African countries saddled with the highest burden of HIV.