Bilateral Middle Cerebral Artery Research Articles

Feasibility of transcranial Doppler to evaluate vasculopathy among survivors of childhood brain tumors exposed to cranial radiation therapy.

The ability of transcranial Doppler (TCD) to detect asymptomatic cerebrovascular disease among childhood brain tumor survivors following exposure to cranial radiation therapy has not been established. Survivors of childhood brain tumors, more than 3years since diagnosis and exposed to greater than 30Gy cranial radiation, underwent a history and physical exam, laboratory biomarkers of cerebrovascular disease (cholesterol, high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), high-sensitivity CRP, hemoglobin A1C, apoprotein A, and apoprotein B), and a TCD evaluation of their cerebral arteries. In all 165 cerebral arteries from 13 patients (medulloblastoma=10; germ cell tumor=3; females=5; mean age at diagnosis=8.0years; mean age at time of study=20.9years) were examined. Twenty-eight of 165 (17%) were considered abnormal by pre-specified criteria. Total 114 cerebral arteries from 13 patients were assessed for greater than 50% stenosis velocities. Arteries most likely to be considered abnormal included the distal bilateral vertebral arteries (right 38%, left 30%), basilar artery 30%, bilateral siphon internal carotid arteries (right 30%, left 23%), bilateral middle cerebral arteries (23% bilaterally), and bilateral anterior cerebral arteries (7% bilaterally). Two vessels had mean flow velocities consistent with 50% stenosis (1.8%). No vessels were found to have greater than 80% stenosis. TCD may be a useful and practical tool to examine asymptomatic cerebrovascular disease among childhood brain tumor survivors after exposure to cranial radiation therapy. Posterior circulation vessels appear to have the highest burden of disease in this group of brain tumor survivors, a majority of whom had medulloblastoma.

Macrovascular blood flow and microvascular cerebrovascular reactivity are regionally coupled in adolescence.

Cerebrovascular imaging assessments are particularly challenging in adolescent cohorts, where not all modalities are appropriate, and rapid brain maturation alters hemodynamics at both macro- and microvascular scales. In a preliminary sample of healthy adolescents (n=12, 8-25 years), we investigated relationships between 4D flow MRI-derived blood velocity and blood flow in bilateral anterior, middle, and posterior cerebral arteries and BOLD cerebrovascular reactivity in associated vascular territories. As hypothesized, higher velocities in large arteries are associated with an earlier response to a vasodilatory stimulus (cerebrovascular reactivity delay) in the downstream territory. Higher blood flow through these arteries is associated with a larger BOLD response to a vasodilatory stimulus (cerebrovascular reactivity amplitude) in the associated territory. These trends are consistent in a case study of adult moyamoya disease. In our small adolescent cohort, macrovascular-microvascular relationships for velocity/delay and flow/CVR change with age, though underlying mechanisms are unclear. Our work emphasizes the need to better characterize this key stage of human brain development, when cerebrovascular hemodynamics are changing, and standard imaging methods offer limited insight into these processes. We provide important normative data for future comparisons in pathology, where combining macro- and microvascular assessments may better help us prevent, stratify, and treat cerebrovascular disease.

Oxygen extraction fraction change in M1-M6 brain regions of patients with unilateral or bilateral middle cerebral artery occlusion.

Cerebral blood flow (CBF) and oxygen extraction fraction (OEF) can be measured using arterial spin labeling (ASL) and quantitative susceptibility mapping (QSM) sequences, respectively. ASL and QSM sequences were performed on 13 healthy participants and 46 patients with unilateral or bilateral Middle cerebral artery (MCA) occlusion. M1-M3 and M4-M6 correspond to anterior, lateral, and posterior MCA territories within the insular ribbon and centrum semiovale, respectively. In patients with unilateral MCA occlusion, significant decreases in CBF were observed in the lesions in M1, M3, M5 and M6 regions, as well as in the contralateral M3 and M5 regions. The OEF of the lesion in the M1-M4 and M6 regions, and the contralateral M1-M3 regions were significantly higher. Additionally, the cerebral metabolic rate of oxygen (CMRO2) in the lesions of the M3 and M6 regions, and the contralateral M3 region, were significantly lower compared to the corresponding regions of healthy participants. For patients with bilateral MCA occlusion, the CMRO2 in the left M5 region and the right M3 and M6 regions were significantly lower than that in the corresponding regions of healthy participants. In conclusion, abnormal hemodynamics occur in the contralateral hemisphere of patients with unilateral MCA occlusion.

Newly formed and ruptured infectious intracranial aneurysm in few days following first intracranial aneurysm embolization concurrent with middle cerebral artery occlusion: A regrettable case in a baby child

AbstractInfectious intracranial aneurysm (IIA) and embolic cerebral infarction are well‐known devastating complications of children suffering infective endocarditis. In this report, we describe a successfully embolized IIA concurrent with bilateral middle cerebral artery (MCA) occlusion. Unfortunately, a newly formed IIA located in the contralateral MCA bifurcation ruptured at the seventh day following embolization. A 6‐month‐old female child was admitted to hospital 3 days following acute right limb mobility disorder. An interventional surgery history of congenital heart disease was confirmed. She was immediately started on antibiotic therapy and the computed tomography agiography (CTA) scan showed occlusion of the upper branch of the left MCA. Unfortunately an IIA was located in the distal artery region (DAR) of the ipsilateral anterior cerebral artery. Angiography (digital subtraction angiography) was performed and the DAR IIA was embolized by OnyX‐18 with Magic 1.2 Fr. microcatheter. On the sixth day, magnetic resonance imaging during the hospital stay showed reduced infarction area with no other special sign. Desperately, a major seizure with opisthotonos attacked the baby on the seventh day after embolization. An immediate CTA scan showed massive hematoma in the right basal ganglia and a ruptured bifurcate aneurysm of the right MCA. The parents refused positive treatment and discharged in considering the critical situation. It should be noted that IIA can be fast formed anywhere in cerebral artery and dynamic angio‐image should be performed as supervision.

A preliminary study on the application of electrical impedance tomography based on cerebral perfusion monitoring to intracranial pressure changes.

In intracranial pathologic conditions of intracranial pressure (ICP) disturbance or hemodynamic instability, maintaining appropriate ICP may reduce the risk of ischemic brain injury. The change of ICP is often accompanied by the change of intracranial blood status. As a non-invasive functional imaging technique, the sensitivity of electrical impedance tomography (EIT) to cerebral hemodynamic changes has been preliminarily confirmed. However, no team has conducted a feasibility study on the dynamic detection of ICP by EIT technology from the perspective of non-invasive whole-brain blood perfusion monitoring. In this study, human brain EIT image sequence was obtained by in vivo measurement, from which a variety of indicators that can reflect the tidal changes of the whole brain impedance were extracted, in order to establish a new method for non-invasive monitoring of ICP changes from the level of cerebral blood perfusion monitoring. Valsalva maneuver (VM) was used to temporarily change the cerebral blood perfusion status of volunteers. The electrical impedance information of the brain during this process was continuously monitored by EIT device and real-time imaging was performed, and the hemodynamic indexes of bilateral middle cerebral arteries were monitored by transcranial Doppler (TCD). The changes in monitoring information obtained by the two techniques were compared and observed. The EIT imaging results indicated that the image sequence showed obvious tidal changes with the heart beating. Perfusion indicators of vascular pulsation obtained from EIT images decreased significantly during the stabilization phase of the intervention (PAC: 242.94 ± 100.83, p < 0.01); perfusion index which reflects vascular resistance increased significantly in the stable stage of intervention (PDT: 79.72 ± 18.23, p < 0.001). After the intervention, the parameters gradually returned to the baseline level before compression. The changes of EIT indexes in the whole process are consistent with the changes of middle cerebral artery velocity related indexes shown in TCD results. The EIT image combined with the blood perfusion index proposed in this paper can reflect the decrease of cerebral blood flow under the condition of increased ICP in real time and intuitively. With the advantages of high time resolution and high sensitivity, EIT provides a new idea for non-invasive bedside measurement of ICP.

Assessment of Dynamic Cerebral Autoregulation During Long-Term Exposure to High Altitude in Normal Subjects by Ultrasonography.

To evaluate changes in dynamic cerebral autoregulation (CA) during short-term and long-term exposure to high altitude with ultrasonography, and also study the sex differences in the response of CA to altitude. We assessed the differences in dynamic CA and measured with Doppler ultrasound of the bilateral internal carotid artery (ICA), vertebral artery (VA), and middle cerebral artery (MCA) and the values of basic information within 48 hours and at 2 years after arrival at Tibet in 65 healthy Han young Chinese volunteers, meanwhile, we compared the resistance index (RI) and pulsatility index (PI) of the right MCA at inhale oxygen 8 minutes when a newcomer with 2 years after arrival at Tibet. With 2 years of altitude exposure, the SaO2 of all subjects was above 90%, the mean PEF, DAP, and HR values decreased, HGB increased compared within 48 hours in same-gender groups. Comparisons of cerebral hemodynamics between before 2 years and after 2 years within male and female groups, the mean RI and PI values of bilateral MCA after 2 years were significantly higher than before 2 years, at the same time, the mean RI and PI values of bilateral ICA were significant differences (P < .05) between male groups, with regard to female groups, showed that the mean RI and PI values of bilateral VA were significant differences (P < .05). Comparisons of Right MCA hemodynamics between after oxygen uptake 8 minutes and 2 years, the mean RI and PI values were no significant difference within male and female groups (P > .05). Acute mountain sickness could result from an alteration of dynamic autoregulation of cerebral blood flow, but the impaired autoregulation may be corrected with the extension of time, furthermore, the response of CA to altitude in males and females are different.

REDUCED AEROBIC FITNESS IS ASSOCIATED WITH IMPAIRED CEREBROVASCULAR FUNCTION IN INDIVIDUALS WITH ATRIAL FIBRILLATION

INTRODUCTION &amp; AIMS Lower aerobic fitness (V̇O2peak) is associated with higher risk of cerebrovascular disease. However, the relationship between V̇O2peak and cerebrovascular function and cerebral blood velocity at rest and during exercise has not been investigated in adults with atrial fibrillation (AF). We aimed to compare resting and exercise cerebral blood velocity responses and cerebrovascular function in individuals with AF to healthy controls. METHODS Eight inactive adults either with AF or healthy age-matched controls (AF: n=4, 64±6 years, 50% female; control: n=4, 66±4 years, 75% female) completed a maximal graded exercise test to measure V̇O2peak. Transcranial Doppler was used to measure bilateral middle cerebral artery velocity (MCAv). Vascular function was assessed by measuring MCAv increases and time to peak following a 30s hypercapnia stimulus (9% CO2, 21% O2, and balanced nitrogen), and MCAv during aerobic exercise (3-minute stages at 40%, 60% and 80% V̇O2peak). Blood pressure, heart rate and end-tidal gases were collected alongside MCAv. RESULTS Compared to controls, individuals with AF (both P&amp;lt;0.01) had higher BMI (AF: 31.8±2.0 kg/m2; control: 27.3±0.6 kg/m2), lower V̇O2peak (AF: 19.9±2.5 mL/kg/min; control: 33.7±5.8 mL/kg/min), and similar blood pressure. Resting right and left MCAv was higher in the AF group (R: 66.6±34.0 cm/s; L: 44.2±10.1 cm/s) compared to the control (R: 36.1±6.7 cm/s; L: 34.9±8.7 cm/s); this was not significant (P=0.121 and 0.258). Right MCAv was higher than left MCAv in individuals with AF but this was not significant (P=0.247). Hypercapnia and exercise induced MCAv and time to peak were similar between groups (P&amp;gt;0.05). CONCLUSION Lower V̇O2peak may be associated with increased resting MCAv in individuals with AF. Furthermore, there may be regional disparities in MCAv in individuals with AF. Future studies with larger sample sizes investigating potential mechanisms and volumetric cerebrovascular changes (e.g., vessel diameter, arterial stiffness) in AF are warranted.

Moyamoya Syndrome in a Child with Beta-Thalassemia Trait: A Case Report with Review of Literature

Background: The association of moyamoya angiopathy with hematological conditions such as sickle cell anemia and beta-thalassemia major or intermedia is well-known, but moyamoya syndrome (MMS) associated with thalassemia trait is hardly reported. We report such a rare association. Clinical Description: A 7-year-old boy presented with right-sided monoparesis with right-sided focal seizures, along with right-sided upper motor neuron type facial nerve palsy. He had a history of recurrent transient episodes of limb weakness, which were unevaluated. Examination revealed pallor and mild splenomegaly. Management and Outcome: Routine investigations revealed microcytic hypochromic anemia with normal serum iron levels. High-performance liquid chromatography was suggestive of beta-thalassemia trait. Contrast-enhanced computerized tomography of the head showed infarction in the territory of the left anterior cerebral artery (ACA) and middle cerebral artery (MCA). Magnetic resonance angiography revealed significantly attenuated bilateral internal carotid arteries in the supraclinoid region with attenuated bilateral ACA and bilateral MCA along with collateral formation suggestive of moyamoya angiopathy. The final diagnosis of MMS secondary to beta-thalassemia trait was made. The child improved with aspirin and supportive management. Conclusion: MMS can be rarely associated with the beta-thalassemia trait. Such an underlying, unsuspected heterozygous beta-thalassemia (trait) may be diagnosed only after the identification of moyamoya disease following a stroke.

A Comparative Study of Transcranial Color-Coded Doppler (TCCD) and Transcranial Doppler (TCD) Ultrasonography Techniques in Assessing the Intracranial Cerebral Arteries Haemodynamics.

Cerebrovascular disease (CVD) poses a major public health and socio-economic burden worldwide due to its high morbidity and mortality rates. Accurate assessment of cerebral arteries' haemodynamic plays a crucial role in the diagnosis and treatment management of CVD. The study compared a non-imaging transcranial Doppler ultrasound (TCD) and transcranial color-coded Doppler ultrasound (with (cTCCD) and without (ncTCCD)) angle correction in quantifying middle cerebral arteries (MCAs) haemodynamic parameters. A cross-sectional study involving 50 healthy adults aged ≥ 18 years was conducted. The bilateral MCAs were insonated via three trans-temporal windows (TTWs-anterior, middle, and posterior) using TCD, cTCCD, and ncTCCD techniques. The MCA peak systolic velocity (PSV) and mean flow velocity (MFV) were recorded at proximal and distal imaging depths that could be visualised on TCCD with a detectable spectral waveform. A total of 152 measurements were recorded in 41 (82%) subjects with at least one-sided open TTW across the three techniques. The mean PSVs measured using TCD, ncTCCD, and cTCCD were 83 ± 18 cm/s, 81 ± 19 cm/s, and 93 ± 21 cm/s, respectively. There was no significant difference in PSV between TCD and ncTCCD (bias = 2 cm/s, p = 1.000), whereas cTCCD yielded a significantly higher PSV than TCD and ncTCCD (bias = -10 cm/s, p < 0.001; bias = -12 cm/s, p ≤ 0.001, respectively). The bias in MFV between TCD and ncTCCD techniques was (bias = -0.5 cm/s; p = 1.000), whereas cTCCD demonstrated a higher MFV compared to TCD and ncTCCD (bias = -8 cm/s, p < 0.001; bias = -8 cm/s, p ≤ 0.001, respectively). TCCD is a practically applicable imaging technique in assessing MCA blood flow velocities. cTCCD is more accurate and tends to give higher MCA blood flow velocities than non-imaging TCD and ncTCCD techniques. ncTCCD is comparable to non-imaging TCD and should be considered in clinical cases where using both TCD and TCCD measurements is needed.

Abstract WP194: Quantified Effects of Intra-Arterial Vasodilatory Therapy for Cerebral Vasospasm

Introduction: Cerebral vasospasm is a major cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage (aSAH). Though used routinely in clinical practice, objective metrics to evaluate effectiveness of intra-arterial vasodilatory treatment (IAT) have not been identified. To quantify effects of IAT on flow dynamics in cerebral vasospasm, we retrospectively compared Lindegaard ratios (LR) of aSAH patients pre-and post-IAT. Methods: Subjects included 24 aSAH patients undergoing IAT in the bilateral middle cerebral arteries (MCA) for cerebral vasospasm, diagnosed by standard clinical and radiographic criteria. Subjects were excluded if balloon angioplasty was performed prior to/within 2 days of the index procedure. All subjects received 10 mg IA milrinone, a non-catecholamine phosphodiesterase inhibitor drug, per MCA. Transcranial doppler (TCD) ultrasound was measured pre-IAT (D0) and at D+1 and D+2 post-IAT. LR was calculated as the ratio of mean flow velocities in the middle cerebral artery (MCA) to the ipsilateral extracranial internal carotid artery. Standard threshold for vasospasm is defined as LR&gt;3. Results: Right and left LR were aggregated, total N=48. Average pre-IAT LR was 2.96 (R 2.67/L 3.25±1.29). Post-IA LR were 2.72±1.12 and 3.15±1.55 at D+1 and D+2, respectively. Subjects with pre-IA LR&gt;3 showed an average LR decrease of 21% post-IAT D+1 (p=0.01) and an 8% decrease at D+2 (p=0.16) [Fig.1A]. Subjects with pre-IAT&lt;3 experienced an average LR increase of 28% by D+2 (p=0.02) [Fig 1B]. Conclusion: Subjects with TCD confirmed vasospasm (LR&gt;3) at D0 showed a significant improvement in cerebral blood flow one day after therapy. Subjects who did not meet TCD threshold for vasospasm (LR&lt;3) showed little change one day post-IAT but worsening cerebral blood flow by day two post-IAT. Further study is needed to determine whether LR can be used to predict benefit or objectively assess effectiveness of IAT in aSAH patients with cerebral vasospasm.

Abstract WP121: Cerebral Hemodynamics in the First Week Postpartum in Healthy Women and Women With Preeclampsia

Objective: Standard adult normative data for transcranial Doppler (TCD)-based cerebral hemodynamic measures, such as mean and peak cerebral blood flow velocity (mCBFV, pCBFV), are used to identify pathological conditions such as postpartum angiopathy. However, little is known about cerebral hemodynamics during the early postpartum period, particularly in patients with preeclampsia (PEC). We characterized cerebral hemodynamics using TCD in the first week postpartum in patients with and without PEC. Methods: We prospectively recruited women with PEC and normotensive pregnant women delivering at an urban academic medical center. We measured CBFV in the bilateral middle cerebral arteries with TCD and calculated systolic mCBFV and pCBFV as well as pulsatility index (PI) and PI-derived noninvasive intracranial pressure (nICP). We compared systolic mCBFV and pCBFV between postpartum women with and without PEC, and historical data from non-pregnant young adult female controls. Results: Subjects were 51 women with PEC, 19 normotensive postpartum women, and 28 non-pregnant historical controls. In the PEC group, median mCBFV was 75.0 cm/s (IQR 65.2-99.1) and median pCBFV was 106.9 cm/s (IQR 92.7-130.8). In the normotensive postpartum group, median mCBFV was 77.1 cm/s (IQR 66.0-92.3) and median pCBFV was 107.9 cm/s (IQR 96.6-127.4). In the non-pregnant female control group, median mCBFV was 62.0 cm/s (IQR 48.5-67.9) and median pCBFV was 83.6 cm/s (IQR 69.3-95.2) (p&lt;0.0001 for mean and peak 3-way comparisons; see Figure). PI and nICP were within normal range in both postpartum groups and did not differ significantly between groups. Conclusion: Postpartum women with and without PEC had mCBFV and pCBFV significantly higher than non-pregnant controls, and many fell outside the standard normal range for healthy adults, but PI and nICP were within normal range. Standard ranges of CBFV for healthy adults may not apply in the postpartum period.

Depression of dynamic cerebral autoregulation during neural activation: The role of responders and non-responders

Neurovascular coupling (NVC) interaction with dynamic cerebral autoregulation (dCA) remains unclear. We investigated the effect of task complexity and duration on the interaction with dCA. Sixteen healthy participants (31.6 ± 11.6 years) performed verbal fluency (naming-words (NW)) and serial subtraction (SS) paradigms, of varying complexity, at durations of 05, 30 and 60 s. The autoregulation index (ARI), was estimated from the bilateral middle cerebral artery blood velocity (MCAv) step response, calculated by transfer function analysis (TFA), for each paradigm during unstimulated (2 min) and neuroactivated (1 min) segments. Intraclass correlation (ICC) and coefficient of variation (CV) determined reproducibility for two visits and objective criteria were applied to classify responders (R) and non-responders (NoR) to task-induced MCAv increase. ICC values demonstrated fair reproducibility in all tasks. ARI decreased in right (RH) and left (LH) hemispheres, irrespective of paradigm complexity and duration (p < 0.0001). Bilateral ARI estimates were significantly decreased during NW for the R group only (p < 0.0001) but were reduced in both R (p < 0.0001) and NoR (p = 0.03) groups for SS tasks compared with baseline. The reproducible attenuation of dCA efficiency due to paradigm-induced NVC response, its interaction, and different behaviour in R and NoR, warrant further research in different physiological and clinical conditions.

Modeling the mechanisms of non-neurogenic dynamic cerebral autoregulation.

Dynamic cerebral autoregulation (dCA) refers to a collection of mechanisms that act to maintain steady state cerebral blood flow (CBF) near constant despite changes in arterial blood pressure (ABP), but which is known to become impaired in various cerebrovascular diseases. Currently, the mechanisms of dCA and how they are affected in different physiological conditions are poorly understood. The objective of this study was to disentangle the magnitudes and time scales of the myogenic and metabolic responses of dCA, in order to investigate how each mechanism is affected in impaired dCA. A physiological model of dCA was developed, where both the myogenic and metabolic responses were represented by a gain and time constant. Model parameters were optimized with pressure-flow impulse responses under normocapnia, thigh cuff, and hypercapnia conditions. The impulse responses were derived by applying transfer function analysis (TFA) to experimental recordings of ABP (Finapres), end-tidal CO2 (capnograph), and CBF velocity (transcranial doppler ultrasound in bilateral middle cerebral arteries). The myogenic gain to time constant ratio was significantly smaller (p-values < 0.001 using both univariate and multivariate TFA), and the metabolic time constant was significantly larger (p-values < 0.001 using both univariate and multivariate TFA) in hypercapnia compared to normocapnia. Both the myogenic and metabolic responses were shown to be affected in impaired dCA, and the metabolic response was shown to be slowed down. This study contributes to the understanding of the complexities of dCA and how it is affected in different physiological conditions.

Effect of surgical mask and N95 respirator mask use on cerebrovascular reactivity.

<p>Face masks are crucial parts of personal protective equipment (PPE) to reduce the risk of respiratory infections. The COVID-19 outbreak has increased healthcare workers&rsquo; use of face masks. This study aimed to evaluate changes in cerebrovascular response among healthcare workers using surgical and N95 respirator masks.&nbsp;</p>. <p>90 healthcare workers: 30 wearing surgical masks, 30 wearing N95 respirators, and 30 without masks were included. After two-hour of face mask use, the baseline mean flow velocity (MFV) and the mean breath-holding index (BHI) of the bilateral middle cerebral arteries (MCAs) were evaluated with transcranial Doppler ultrasound. The presence of de-novo headache was recorded. BHI values ​​below 0.69 were evaluated as a sign of impaired cerebrovascular reactivity (CVR).&nbsp;</p>. <p>The rate of de-novo headache was significantly higher in the N95 respirator mask group (p = 0.004). Compared to the control and surgical mask groups, the N95 respirator mask group had significantly lower values of the baseline MFV of the right MCA (p = 0.003 and p = 0.021, respectively) and mean BHI (p = 0.003 and p = 0.012, respectively). Still, only one N95 respirator mask user had a mean BHI value below 0.69.</p>. <p>Surgical masks did not signi&shy;fi&shy;cantly affect cerebral hemodynamics. Although N95 respirator mask use significantly decreased BHI values, the CVR is still within normal limits, and the development of de-novo headache is not directly associated with low CVR.&nbsp;</p>.

Acute bilateral middle cerebral artery occlusion treated with thrombectomy via the anterior communicating artery in a patient with chronic left cervical internal carotid artery occlusion: a case report

Acute bilateral middle cerebral artery occlusion treated with thrombectomy via the anterior communicating artery in a patient with chronic left cervical internal carotid artery occlusion: a case report

Exploring Cerebral Perfusion Transcranial Doppler Parameters in Patients Admitted to Combined Medical Surgical Intensive Care Unit

Introduction: Encephalopathy, a common complication in Intensive Care Unit (ICU) patients, is often linked to poor outcomes. Transcranial Doppler (TCD), a non-invasive tool assesses cerebral perfusion via the Pulsatility Index (PI), Resistivity Index (RI), and Time-Averaged Peak (TAP) or Mean Flow Velocity (MFV). These parameters may offer insights into cerebral perfusion and outcomes in encephalopathic patients. Aim: To describe the PI, RI of the Middle Cerebral Artery (MCA), and MFV or TAP measured by TCD in patients admitted to the ICU, comparing those with and without encephalopathy at the time of admission. Materials And Methods: This cross-sectional observational study was conducted from January 2019 to November 2020, in a combined medical-surgical ICU of a tertiary care hospital, involving 45 enrolled patients. Patients were evaluated within 24 hours of admission and subsequently every 24 hours until ICU discharge, death, or discharge against medical advice. Bilateral Middle cerebral artery TCD studies were conducted using a 1-5 MHz phased array probe or TCD mode through the transtemporal window. The PI, RI, and MFV were measured on both sides, with the higher value used for analysis, and all statistical analyses were performed using Statistics and Data 13 software. Results: In the present study, 88% (n=40) of patients had encephalopathy (GCS&lt;15 and RAAS less than or more than 0). The mean APACHE II score was 19 (14-25), indicating severe illness with a predicted mortality of 30-40%. Patients with encephalopathy had significantly higher APACHE II scores compared to those without (19.5 (16-25) vs 10 (4-19)). Although there was a trend towards a higher Pulsatility Index in encephalopathic patients at admission (1.11±0.378 vs 1.07±0.12, p=0.81), PI, RI, and TAP values did not significantly differ in non-survivors (1.12±0.49 vs 1.11±0.33, p=0.750). Persistent encephalopathy was associated with a trend towards higher PI at admission (1.05±0.24 vs 1.16±0.46; p=0.756), and a moderate correlation was found between decreasing PI and improvement in GCS (rho=-0.489, p=0.001). Conclusions: PI, RI, and TAP at the time of admission were not found to be associated with occurrence and recovery of encephalopathy as well as mortality. The trend of change in PI moderately correlated with improvement in GCS suggesting the importance of trends rather than absolute values.

Lateral medullary infarction in a patient with Moyamoya disease associated with RNF213 variants: a case report

Background: Moyamoya disease (MMD) is a rare cerebrovascular disease radiologically characterized by progressive bilateral occlusion of the distal portion of the internal carotid artery and compensating collaterals. Herein, we report a case of medullary infarction in a patient with MMD.Case Report: We present the case of a 54-year-old male with hypertension, hyperlipidemia, and unstable angina with sudden onset dysarthria and ataxia. Diffusion-weighted and T2-weighted images of magnetic resonance imaging showed a high-signal intensity lesion on the right lateral medulla, suggestive of acute infarction. Transfemoral cerebral angiography also demonstrated bilateral middle cerebral artery (MCA) occlusion. Testing of the ring finger protein 213 (RNF213) gene revealed a homozygous p.R4810K variant that was possibly associated with posterior circulation involvement.Conclusion: When the MCA is occluded in MMD, there is a possibility that medullary infarction may occur due to the mechanism of increased hemodynamic stress on the anastomotic posterior vessels.

Improving the impact of different input arteries on cerebral CT perfusion parameters and ischemic penumbra

This study aims to examine the impact of different input arteries on cerebral perfusion parameters and the volume of core infarction, ischemic area, and penumbra automatically measured by software in post-processing 256-slice CT brain perfusion images. Retrospective analysis was conducted on brain perfusion images of 58 patients who underwent 256-slice multidetector CT examination for cerebral infarction. Various input arteries, including bilateral internal carotid artery (ICA), bilateral middle cerebral artery (MCA), anterior cerebral artery (ACA), and basilar artery (BA), were selected for image processing and measurements. The volumes of core infarction, ischemic area, and penumbra were automatically calculated using software. Additionally, manual measurements were per-formed by experienced doctors. Perfusion parameters including cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and time to peak (TTP) were evaluated. The change of input artery resulted in a significant difference in CBF and MTT in the penumbra and normal brain tissue areas. However, no significant difference was observed in CBV, TTP, and perfusion parameters in the core infarct area. The volumes of core infarction acquired from different input arteries showed no significant difference. Nonetheless, significant differences were found in the volume of the ischemic area and the mismatched area. The selection of different input arteries affects CT cerebral perfusion parameter values and the automatic measurement of the ischemic area and penumbra by software. Thus, when performing post-processing of CT cerebral perfusion images, it is advisable to choose the thicker internal carotid artery on the healthy side as the input artery.

Cerebral blood flow and neurocognition in patients undergoing transcatheter aortic valve replacement for severe aortic stenosis.

Aortic valve stenosis (AS) results in higher systolic pressure to overcome resistance from the stenotic valve, leading to heart failure and decline in cardiac output. There has been no assessment of cerebral blood flow (CBF) association with neurocognition in AS or the effects of valve replacement. The goal was to determine if AS is associated with altered cerebral haemodynamics and impaired neurocognition, and whether transcatheter aortic valve replacement (TAVR) improves haemodynamics and cognition. In 42 patients with planned TAVR, transcranial Doppler (TCD) assessed bilateral middle cerebral artery (MCA) mean flow velocities (MFVs); abnormality was <34.45 cm/s. The neurocognitive battery assessed memory, language, attention, visual-spatial skills, and executive function, yielding a composite Z-score. Impairment was <1.5 SDs below the normative mean. The mean age was 78 years, 59% Male, and the mean valve gradient was 46.87 mm/Hg. Mean follow-up was 36 days post-TAVR (range 27-55). Pre-TAVR, the mean MFV was 42.36 cm/s (SD = 10.17), and the mean cognitive Z-score was -0.22 SDs (range -1.99 to 1.08) below the normative mean. Among the 34 patients who returned after TAVR, the MFV was 41.59 cm/s (SD = 10.42), not different from baseline (P = 0.66, 2.28-3.67). Post-TAVR, average Z-scores were 0.17 SDs above the normative mean, not meeting the pre-specified threshold for a clinically significant 0.5 SD change. Among patients with severe AS, there was little impairment of MFV on TCD and no correlation with cognition. Transcatheter aortic valve replacement did not affect MFV or cognition. Assumptions about diminished CBF and improvement after TAVR were not supported.

P103: Middle Cerebral Artery Stenosis is Associated with Severity of Depression in Elderly Patients: Magnetic Resonance Angiography (MRA) Findings

Objective:Vascular abnormalities have been frequently reported in elderly adults as a potential risk factor of late-life depression. However, it is still unclear whether stenosis of cerebral arteries may increase risk of depression in the elderly.Methods:Study participants were 365 patients 65 years or older with depressive disorder who had undergone brain MRI and angiography (MRA) which were assessed by trained radiologists, and the 15-item Geriatric Depression Scale (GDS-15) and the Mini Mental State Examination (MMSE), and blood glucose and lipid profiles.Results:Of the 365 subjects, 108 had at least one location of cerebral artery stenosis (29.59%). Stenosis was associated with age, marital status, infarction, and atherosclerosis. In multivariable linear regression analysis of different locations of stenosis among the whole sample, only bilateral middle cerebral artery (MCA) stenosis was found to have a significant association with higher GDS-15 score (p= 0.0138), and more than 8 scores in the GDS-15 (p= 0.0045), but no significant associations with ACA (anterior cerebral artery), PCA (posterior cerebral artery) or ICA (internal carotid artery). In multivariable linear logistic analysis of different locations among patients with at least one cerebral artery stenosis, left MCA was found to be significantly related to higher GDS-15 scores but not with right MCA (p = 0.0202).Conclusion:MCA stenosis is significantly associated with severity of depression in elderly adults with cerebral artery stenosis, especially in those with left MCA stenosis.Key pointsPatients with cerebral artery stenosis found with brain magnetic resonance angiography (MRA) were associated with higher depression severity.Stenosis of both left and right middle cerebral artery (MCA) was associated with greater depression severity, with left MCA stenosis having a greater influence on depression severity than right MCA stenosis.Higher depression severity in patients with MCA stenosis suggests that depression in elderly patients is mediated at least in part by vascular pathology of MCA supplied regions and careful investigation and management of cerebral artery stenosis and their risk factors may help reduce the severity of depression in elderly patients who visit psychiatrists.