Transcranial Magnetic Resonance Research Articles

A novel high-precision fiber tractography for nuclear localization in transcranial magnetic resonance-guided focused ultrasound surgery: a pilot study.

In transcranial MR-guided focused ultrasound (TcMRgFUS), fiber tractography using diffusion tensor imaging (DTI) has been proposed as a direct method to identify the ventral intermediate nucleus (Vim), the ventral caudal nucleus (Vc), and the pyramidal tract (PT). However, the limitations of the DTI algorithm affect the accuracy of visualizing anatomical structures due to its low-quality fiber tractography, whereas the application of the generalized q-sampling imaging (GQI) algorithm enables the visualization of high-quality fiber tracts, offering detailed insights into the spatial distribution of motor cortex fibers. This retrospective study aimed to investigate the usefulness of high-precision fiber tractography using the GQI algorithm as a planning image in TcMRgFUS to achieve favorable clinical outcomes. This study included 20 patients who underwent TcMRgFUS. The Clinical Rating Scale for Tremor (CRST) scores and MR images were evaluated pretreatment and at 24 hours and 3-6 months after treatment. Cases were classified based on the presence and adversity of adverse events (AEs): no AEs, mild AEs without additional treatment, and severe AEs requiring prolonged hospitalization. Fiber tractography of the Vim, Vc, and PT was visualized using the DTI and GQI algorithm. The overlapping volume between Vim fibers and the lesion was measured, and correlation analysis was performed. The relationship between AEs and the overlapping volume of the Vc and PT fibers within the lesions was examined. The cutoff value to achieve a favorable clinical outcome and avoid AEs was determined using receiver operating characteristic curve analysis. All patients showed improvement in tremors 24 hours after treatment, with 3 patients experiencing mild AEs and 1 patient experiencing severe AEs. At the 3- to 6-month follow-up, 5 patients experienced recurrence, and 2 patients had persistent mild AEs. Although fiber visualization in the motor cortex using the DTI algorithm was insufficient, the GQI algorithm enabled the visualization of significantly higher-quality fibers. A strong correlation was observed between the overlapping volume that intersects the lesion and Vim fibers and the degree of tremor improvement (r = 0.72). Higher overlapping volumes of Vc and PT within the lesion were associated with an increased likelihood of AEs (p < 0.05); the cutoff volume of Vim fibers within the lesion for a favorable clinical outcome was 401 mm3, while the volume of Vc and PT within the lesion to avoid AEs was 99 mm3. This pilot study suggests that incorporating the high-precision GQI algorithm for fiber tractography as a planning imaging technique for TcMRgFUS has the potential to enhance targeting precision and achieve favorable clinical outcomes.

Long‐term outcome following magnetic resonance imaging‐guided focused ultrasound unilateral thalamotomy for medication‐refractory essential tremor

AbstractObjectiveTo investigate the long‐term outcome 5 years after transcranial magnetic resonance imaging‐guided focused ultrasound (MRgFUS) unilateral ventral intermediate nucleus (Vim) thalamotomy for essential tremor (ET), following our interim reports.MethodsThis was a prospective and open‐labeled study involving a single center. Ten medication‐refractory ET patients (8 men and 2 women, aged 67.1 ± 17.5 years, all right‐handed) underwent left MRgFUS Vim thalamotomy. They were assessed using the Clinical Rating Scale for Tremor (CRST) and the overall health and quality of life (QOL) scale of the Quality of Life in Essential Tremor Questionnaire (QUEST). Additionally, we assessed safety issues during the study period.ResultsRight‐hand tremor improved immediately after the procedure in all patients. The right‐hand CRST score remained significantly improved by 60.2% and 33.5% from baseline at both 1‐ and 5‐years post‐treatment, respectively (both p &lt; 0.05). On the other hand, the left‐hand CRST score and the overall QOL score of QUEST showed no improvement. Adverse events during and immediately after the procedure were mild and reversible. We observed no delayed adverse events.ConclusionMRgFUS unilateral Vim thalamotomy is adopted as one of the therapeutic options for intractable ET. Further investigation of the methodology for accurate targeting and sonication is important to improve long‐term outcomes involving a larger number of patients. In addition, not only unilateral but also bilateral Vim thalamotomy may be necessary to achieve a better quality of life.

Cerebrovascular disease in patients with antiphospholipid antibody syndrome: a transcranial Doppler and magnetic resonance imaging study.

Transcranial Doppler (TCD) and brain MRI may be useful in evaluating patients with APS, helping to stratify the risk of cerebrovascular ischaemic events in this population. This study aimed to assess the frequency of brain MRI abnormalities in patients with primary antiphospholipid syndrome, secondary antiphospholipid syndrome and SLE and correlate to TCD findings. The study, conducted over four years at two autoimmune disease referral centres, included 22 primary antiphospholipid syndrome patients, 24 secondary antiphospholipid syndrome patients, 27 SLE patients without APS and 21 healthy controls. All participants underwent TCD to assess cerebral haemodynamics, detect microembolic signals and evaluate right-to-left shunts, followed by brain MRI and magnetic resonance angiography. MRI scans were reviewed for acute microembolism, localized cortical infarctions, border infarctions, lacunar infarctions, ischaemic lesions, white matter hyperintensity, micro and macro haemorrhages and arterial stenosis ≥50% of the cervical carotid artery, by two neuroradiologists blinded to the clinical data. Brain MRI findings were similar between the groups, except for lacunar infarction, more frequent in patients with secondary antiphospholipid syndrome (P = 0.022). Patients with intracranial stenosis detected by TCD had a higher frequency of territorial infarction (40% vs 7.5%, P = 0.02), lacunar (40% vs 11.3%, P = 0.075) and border zone infarcts (20% vs 1.9%, P = 0.034). Patients with intracranial stenosis presented a higher frequency of territorial, lacunar and border zone infarcts, suggesting that evaluating the intracranial vasculature should not be neglected in patients with APS and stroke.

Midbrain signaling of identity prediction errors depends on orbitofrontal cortex networks

Outcome-guided behavior requires knowledge about the identity of future rewards. Previous work across species has shown that the dopaminergic midbrain responds to violations in expected reward identity and that the lateral orbitofrontal cortex (OFC) represents reward identity expectations. Here we used network-targeted transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) during a trans-reinforcer reversal learning task to test the hypothesis that outcome expectations in the lateral OFC contribute to the computation of identity prediction errors (iPE) in the midbrain. Network-targeted TMS aiming at lateral OFC reduced the global connectedness of the lateral OFC and impaired reward identity learning in the first block of trials. Critically, TMS disrupted neural representations of expected reward identity in the OFC and modulated iPE responses in the midbrain. These results support the idea that iPE signals in the dopaminergic midbrain are computed based on outcome expectations represented in the lateral OFC.

Effectiveness and brain mechanism of multi-target transcranial alternating current stimulation (tACS) on motor learning in stroke patients: study protocol for a randomized controlled trial

BackgroundTranscranial alternating current stimulation (tACS) has proven to be an effective treatment for improving cognition, a crucial factor in motor learning. However, current studies are predominantly focused on the motor cortex, and the potential brain mechanisms responsible for the therapeutic effects are still unclear. Given the interconnected nature of motor learning within the brain network, we have proposed a novel approach known as multi-target tACS. This study aims to ascertain whether multi-target tACS is more effective than single-target stimulation in stroke patients and to further explore the potential underlying brain mechanisms by using techniques such as transcranial magnetic stimulation (TMS) and magnetic resonance imaging (MRI).MethodsThis study employs a double-blind, sham-controlled, randomized controlled trial design with a 2-week intervention period. Both participants and outcome assessors will remain unaware of treatment allocation throughout the study. Thirty-nine stroke patients will be recruited and randomized into three distinct groups, including the sham tACS group (SS group), the single-target tACS group (ST group), and the multi-target tACS group (MT group), at a 1:1:1 ratio. The primary outcomes are series reaction time tests (SRTTs) combined with electroencephalograms (EEGs). The secondary outcomes include motor evoked potential (MEP), central motor conduction time (CMCT), short interval intracortical inhibition (SICI), intracortical facilitation (ICF), magnetic resonance imaging (MRI), Box and Block Test (BBT), and blood sample RNA sequencing. The tACS interventions for all three groups will be administered over a 2-week period, with outcome assessments conducted at baseline (T0) and 1 day (T1), 7 days (T2), and 14 days (T3) of the intervention phase.DiscussionThe study’s findings will determine the potential of 40-Hz tACS to improve motor learning in stroke patients. Additionally, it will compare the effectiveness of multi-target and single-target approaches, shedding light on their respective improvement effects. Through the utilization of techniques such as TMS and MRI, the study aims to uncover the underlying brain mechanisms responsible for the therapeutic impact. Furthermore, the intervention has the potential to facilitate motor learning efficiency, thereby contributing to the advancement of future stroke rehabilitation treatment.Trial registrationChinese Clinical Trial Registry ChiCTR2300073465. Registered on 11 July 2023.

A Clinical Case of Corticospinal Tract Reorganization of Supplementary Motor Area in a Child After Acute Hypoxic Brain Injury

We present clinical observation of a 3-year-old child during recovery after acute hypoxic brain injury (freshwater drowning). Using diagnostic transcranial magnetic stimulation and magnetic resonance tractography with reconstruction of the corticospinal tract (CST) originated from the primary motor cortex and supplementary motor area (SMA), we determined that hypoxic brain injury induced activation of CST from the SMA. The period of reorganization was associated with the development of epileptiform patterns, that confirms the transient hyperexcitability of cortical neurons. Our findings indicate no recovery of motor function after acute hypoxic brain injury when CST originated only from SMA.

Modeling and evaluation of biomechanics and hemodynamic based on patient-specific small intracranial aneurysm using fluid-structure interaction

Background and ObjectiveRupture of small intracranial aneurysm (IA) often leads to the development of highly fatal clinical syndromes such as subarachnoid hemorrhage. Due to the patient specificity of small IA, there are many difficulties in evaluating the rupture risk of small IA such as multiple influencing factors, high clinical experience requirements and poor reusability. MethodsIn this study, clinical methods such as transcranial doppler (TCD) and magnetic resonance imaging (MRI) are used to obtain patient-specific parameters, and the fluid-structure interaction method (FSI) is used to model and evaluate the biomechanics and hemodynamics of patient-specific small IA. ResultsThe results show that a spiral vortex stably exists in the patient-specific small IA. Due to the small size of the patient-specific small IA, the blood flow velocity still maintains a high value with maximum reaching 3 m/s. The inertial impact of blood flow and vortex convection have certain influence on hemodynamic and biomechanics parameters. They cause three high value areas of WSSM on the patient-specific small IA with maximum of 180 Pa, 130 Pa and 110 Pa, respectively. They also cause two types of WSS concentration points, positive normal stress peak value areas and negative normal stress peak value areas to appear. ConclusionThis paper found that the factors affecting hemodynamic parameters and biomechanical parameters are different. Unlike hemodynamic parameters, biomechanical parameters are also affected by blood pressure in addition to blood flow velocity. This study reveals the relationship between the flow field distribution and changes of patient-specific small IA, biomechanics and hemodynamics.

Poor School Performance As an Indicator of Severity of Sickle Cell Disease

Purpose: Patients with sickle cell anemia can have long term neurocognitive deficits throughout their lifespan. The purpose of this study is to conduct neuropsychiatric evaluations and brain imaging to determine if individuals who have higher risk of falling behind in education can be identified, emphasize the importance of addressing educational needs of these patients, and identify patients who are at risk of developing further complications. Methods: IRB approved retrospective study of patients with Hemoglobin SS disease, who underwent Stanford-Binet Intelligence testing and Woodcock Johnson Achievement. All patients who underwent cognitive testing and also received a transcranial doppler ultrasound or magnetic resonance imaging between were included. All patients were referred to neuropsychiatric testing due to poor school performance. Results: 33 patients were included who underwent neuropsychiatric testing. These students were referred due to poor school performance. Of those, 15 patients had additional imaging studies. All patients were identified with hemoglobin SS disease. All patients were African American. The median age was 9 with an age range of 6 to 16 with a median grade was 4. This sample included 12 females and 3 males. 73% (11 of 15 individuals) were identified with below average full scale intelligence quotient. Of these, 46% (6 of 11) had measurable changes in MRI or transcranial doppler results. 5 of them had measurable changes in transcranial doppler and changes in their MRI, while 1 patient had a normal transcranial doppler, but showed changes in their MRI. On average, the maximum mean velocity was 164 cm/s and was higher than the patients with normal intelligence quotient scores at 148cm/s. The remaining 5 individuals also had below average full scale intelligence quotient without any findings on imaging. All 11 individuals also had below average scores in academic application, academic fluency, and academic skills. On average these patients were 3 years behind on reading, 2 years behind on math, and 2 years behind writing. Only one of these patients had an individualized education plan with extra assistance for education. 7 of the 11 patients with below average full scale intelligence quotients were on hydroxyurea and 2 of the 4 patients with average scores used hydroxyurea. The average hemoglobin level in the group that performed below average was 9.5 and 8.9 in the group that performed average. While, all patients who had average scores on the stanford-binet test did not have any abnormal transcranial dopplers and they all had delays in math, reading, and writing. Conclusion: Below average intelligence and delays in academic performance may be an indicator of patients at risk of developing further complications such as stroke.The full extent to this relationship is unclear. Further research is needed to determine the relationship between intelligence, academic performance and changes in imaging. Earlier detection of these patients can prevent further complications, develop individual treatment plans, and target closer monitoring. A multidisciplinary approach to treating patients with sickle cell disease should include neuropsychiatric evaluations, an assessment of academic achievement, and the opportunity for additional support in school to fully address the needs of this population.

Enhancement of brain hyperthermia via transcranial magnetic resonance imaging-guided focused ultrasound and microbubbles—Heating mechanism investigation using COMSOL

Noninvasive methods for enhancing the brain drug delivery has been pursued for years. Previously we developed a new MR-guided focused ultrasound (FUS)-based technique, which can achieve targeted brain hyperthermia for heat-triggered drug release and simultaneously open the blood–brain barrier safely for drug penetration. However, the underline mechanisms were unclear. This study aimed to explore the mechanisms for the enhanced FUS brain tissue hyperthermia with microbubbles via numerical modeling in COMSOL. The acoustic wave equation was employed to describe the FUS propagation. A bubble dynamics equation was adopted for calculating the stable bubble oscillations under FUS exposures. A modified bioheat transfer equation was utilized to compute the heating, with various heating sources including FUS, microbubble acoustic emission (MAE), and viscous dissipation (VD). The microbubbles were randomly distributed within the focal region. The sonication time was 6s with an initial temperature of 41°C. The average temperature in the focal region were 41.65°C, 42.24°C, 42.98°C, and 43.59°C for FUS alone, FUS + MAE, FUS + VD, and FUS + MAE + VD, respectively. Compared with the FUS alone, both MAE and VD made significant contributions to the heating with additional temperature increases of 47.6% and 67.2%, respectively.

Cerebral microembolic signal burden during pulsed field ablation: preliminary results from robotically-assisted transcranial doppler and magnetic resonance imaging

Abstract Funding Acknowledgements Type of funding sources: None. Background Transcranial Doppler (TCD) has been used to monitor the burden of cerebral microembolic signals (MESs) during atrial fibrillation (AF) ablation. MES burden is considered a surrogate marker for stroke risk and has never been reported during AF ablation with pulsed field ablation (PFA). Purpose To assess the MES burden during AF ablation with point-by-point radiofrequency (RF) versus single-shot PFA. Methods Fifteen consecutive paroxysmal and persistent AF patients underwent catheter ablation via either single-shot (2000V) PFA [n=7, median age: 56yo (range:53-73), 85.7% males] or point-by point (45W) RF [n=8, median age: 58yo (range 56-74), 62.6% males] under uninterrupted oral anticoagulation and a periprocedural ACT≥300s. Peri-procedural TCD was performed via a robotically-assisted ultrasound system, which includes an Artificial Intelligence-powered robotic headset designed to automate signal acquisition and reduce interoperator variability of TCD findings (Figure 1). Ablation-related asymptomatic cerebral embolism (CE) was assessed via diffusion-weighted imaging (DWI) sequences at magnetic resonance imaging (MRI) performed 24-48h post-ablation. Results Among the 7 PFA patients, the median number of applications to achieve PV isolation was 35 (range:33-42). Five (71.4%) patients showed multiple MESs clustered in a shower-like pattern (Figure 2). The overall number of MES-showers was 51 [median: 9 (range:8-15)] and they were temporally correlated with a PFA application. Shower formation was more common after a PFA application to the right superior pulmonary vein [(PV); 19 cases (37.3%)], followed by the right inferior PV [16 cases (31.4%)], the left inferior PV [14 cases (27.5%)], and the left superior PV [2 cases (3.9%)]. A single shower-like pattern was documented among the 8 RF patients, following a stem-pop while ablating at the right inferior PV antrum. There were no procedure-related complications and none of the 15 patients showed any post-ablation neurological symptoms. The mean time from ablation to MRI was 29±4hours; DWI imaging revealed no acute cerebral microembolic lesions. Conclusion PFA generated a relevant number of MESs frequently clustered in short-lasting shower-like patterns. The composition of MESs, their exact mechanism of formation, and the impact on neurological outcomes are unknown and will be addressed in future studies.

Design of coil holder for the improved maneuvering in concurrent TMS-MRI

BackgroundConcurrent transcranial magnetic stimulation (TMS) and magnetic resonance imaging (MRI) is time-consuming because of the limited space in the MRI bore and the sophisticated placement and orientation of the TMS coil to elicit the desired brain activities and behaviors. ObjectiveWe developed a TMS coil holder capable of quick adjustment of the TMS coil position and orientation. The holder can also hold an MRI receiver coil array. MethodsA holder with one controlling knob, two omni-direction rotation joints, and two in-plane rotation joints was developed. ResultsDifferent TMS coil positions and orientations can be arranged and fixed in seconds. The holder can also accommodate two TMS coils to allow for multi-coil TMS-MRI. ConclusionOur development significantly improves the workflow of the concurrent TMS-MRI in new neuroscience studies and clinical applications.

Magnetic Resonance Thermometry Targeting for Magnetic Resonance-Guided Histotripsy Treatments.

The potential of transcranial magnetic resonance (MR)-guided histotripsy for brain applications has been described in prior in vivo studies in the swine brain through an excised human skull. The safety and accuracy of transcranial MR-guided histotripsy (tcMRgHt) rely on pre-treatment targeting guidance. In the work described here, we investigated the feasibility and accuracy of using ultrasound-induced low-temperature heating and MR thermometry for histotripsy pre-treatment targeting in ex vivo bovine brain. A 15-element, 750-kHz MRI-compatible ultrasound transducer with modified drivers that can deliver both low-temperature heating and histotripsy acoustic pulses was used to treat seven bovine brain samples. The samples were first heated to an approximately 1.6°C temperature increase at the focus, and MR thermometry was used to localize the target. Once the targeting was confirmed, a histotripsy lesion was generated at the focus and visualized on post-histotripsy MR images. The accuracy of MR thermometry targeting was evaluated with the mean/standard deviation of the difference between the locus of peak heating identified by MR thermometry and the center of mass of the post-treatment histotripsy lesion, which was 0.59/0.31 mm and 1.31/0.93 mm in the transverse and longitudinal directions, respectively. This study determined that MR thermometry could provide reliable pre-treatment targeting for transcranial MR-guided histotripsy treatment.

Coregistered transcranial optoacoustic and magnetic resonance angiography of the human brain.

Imaging modalities capable of visualizing the human brain have led to major advances in neurology and brain research. Multi-spectral optoacoustic tomography (MSOT) has gained importance for studying cerebral function in rodent models due to its unique capability to map changes in multiple hemodynamic parameters and to directly visualize neural activity within the brain. The technique further provides molecular imaging capabilities that can facilitate early disease diagnosis and treatment monitoring. However, transcranial imaging of the human brain is hampered by acoustic attenuation and other distortions introduced by the skull. Here, we demonstrate non-invasive transcranial MSOT angiography of pial veins through the temporal bone of an adult healthy volunteer. Time-of-flight (TOF) magnetic resonance angiography (MRA) and T1-weighted structural magnetic resonance imaging (MRI) were further acquired to facilitate anatomical registration and interpretation. The superior middle cerebral vein in the temporal cortex was identified in the MSOT images, matching its location observed in the TOF-MRA images. These initial results pave the way toward the application of MSOT in clinical brain imaging.

Effects of cerebellar transcranial direct current stimulation on upper limb motor function after stroke: study protocol for the pilot of a randomized controlled trial

BackgroundTranscranial direct current stimulation (tDCS) is a technique that can noninvasively modulate neural states in a targeted brain region. As cerebellar activity levels are associated with upper limb motor improvement after stroke, the cerebellum is a plausible target of tDCS. However, the effect of tDCS remains unclear. Here, we designed a pilot study to assess: (1) the feasibility of a study that aims to examine the effects of cerebellar tDCS combined with an intensive rehabilitation approach based on the concept of constraint-induced movement therapy (CIMT) and (2) the preliminary outcome of the combined approach on upper limb motor function in patients with stroke in the chronic stage.MethodsThis pilot study has a double-blind randomized controlled design. Twenty-four chronic stroke patients with mild to moderate levels of upper limb motor impairment will be randomly assigned to an active or sham tDCS group. The participants will receive 20 min of active or sham tDCS to the contralesional cerebellum at the commencement of 4 h of daily intensive training, repeatedly for 5 days per week for 2 weeks. The primary outcomes are recruitment, enrollment, protocol adherence, and retention rates and measures to evaluate the feasibility of the study. The secondary outcome is upper limb motor function which will be evaluated using the Action Research Arm Test, Fugl-Meyer Assessment, for the upper extremity and the Motor Activity Log. Additionally, neurophysiological and neuroanatomical assessments of the cerebellum will be performed using transcranial magnetic stimulation and magnetic resonance imaging. These assessments will be conducted before, at the middle, and after the 2-week intervention, and finally, 1 month after the intervention. Any adverse events that occur during the study will be recorded.DiscussionCerebellar tDCS combined with intensive upper limb training may increase the gains of motor improvement when compared to the sham condition. The present study should provide valuable evidence regarding the feasibility of the design and the efficacy of cerebellar tDCS for upper limb motor function in patients with stroke before a future large trial is conducted.Trial registrationThis study has been registered at the Japan Registry of Clinical Trials (jRCTs042200078). Registered 17 December 2020

Complete resolution of chronic cluster headache following central lateral thalamotomy using incisionless MRI-guided focused ultrasound with 6 years of follow-up: illustrative case.

The authors reported the case of a 66-year-old male patient with a 14-year history of right-sided severe episodic and therapy-resistant cluster headache (CH) who underwent bilateral central lateral thalamotomy (CLT) using incisionless transcranial magnetic resonance imaging-guided focused ultrasound (MRgFUS). The patient experienced a single cluster headache attack 5 weeks after the procedure. There were no more pain attacks over the next 6 years of follow-up. This treatment success may indicate a common pathophysiology for CH and neurogenic (neuropathic) pain, which has been treated with CLT for more than 30 years. Further experience is needed to assess the reproducibility of this case.

Delayed cerebral ischemia and therapeutic approaches after subarachnoid hemorrhage

Delayed cerebral ischemia after subarachnoid hemorrhage is one of the most important causes of mortality and poor functional outcome in patients. Initially, the etiology and treatment of delayed cerebral ischemia focused primarily on cerebral vasospasm. However, recent studies have detected that depolarization, microcirculation, and autoregulation disorder, which spreads together with cerebral vasospasm, also play a role in the etiology. The main treatment strategies in the prevention and treatment of delayed cerebral ischemia are the regulation of blood pressure and the use of calcium channel blockers, especially nimodipine. The main step in the early diagnosis and treatment of the disease is to monitor the neurological clinical status. In addition to transcranial Doppler ultrasonography, computed tomography, or magnetic resonance imaging angiography, continuous electroencephalography and invasive brain multimodal examination may be required in the follow-up period of the disease. In addition to blood pressure regulation, optimization of cardiac output, endovascular interventions, angioplasty, and/or intra-arterial vasodilator infusion are other treatment methods. This review aimed to evaluate delayed cerebral ischemia, one of the most important complications of subarachnoid hemorrhage, in the light of current literature.

Small Demyelination of the Cortex May Be a Potential Marker for the Right-to-Left Shunt of the Heart.

Migraine is a common clinical primary headache with unclear aetiology. In recent years, studies have shown that migraine is related to right-to-left shunts (RLS), and some patients with migraine have white matter lesions. However, the relationship among the three is unclear. To explore the characteristics of white matter lesions (WMLs) in migraine patients with right-to-left shunts and to predict the presence of right-to-left shunts through magnetic resonance imaging (MRI) characteristics in patients with migraine, we conducted a retrospective study. We enrolled 214 patients who were diagnosed with migraines in an outpatient clinic from January 2019 to December 2021. All of them had completed contrast transcranial Doppler ultrasound (cTCD) and magnetic resonance imaging (MRI) examination. Through the inclusion and exclusion criteria, 201 patients were finally included. The patients were grouped according to the presence of WMLs and were compared by age, sex, hypertension, diabetes, RLS, and other characteristic data. We observed the MRI fluid attenuation inversion recovery sequence (FLAIR) image and compared the differences in WMLs between the RLS-positive group and the RLS-negative group. There were 71 cases and 130 cases of migraine with and without WMLs, respectively. A statistically significant difference in near-cortical WMLs with RLS in migraine patients was observed (p = 0.007). Logistic regression analysis was adjusted by age, sex, duration of migraine, and severity. Migraine with aura and family history identified the RLS status as the sole determinant for the presence of near-cortical WMLs (OR = 2.69; 95%CI 1.386–5.219; p = 0.003). Near-cortical white matter lesions in migraine patients are related to RLS, especially in the blood supply area of the anterior cerebral artery. This small demyelination of the near-cortical WMLs may be a potential marker for the right-to-left shunt of the heart. Transcranial Doppler ultrasonography may help finding more RLS in migraineurs with near-cortical WMLs.

Effect of Cyclooxygenase Inhibitor on Hypoxia Stimulated Cerebral Blood Flow Using Arterial Spin Labeling Magnetic Resonance

IntroductionThe purpose of this study was twofold: 1) to determine microvascular cerebral blood flow (CBF) during hypoxia and 2) to investigate the effect of Ketorolac, a cyclooxygenase (COX) inhibitor, on hypoxia stimulated CBF. Acute exposure to hypoxic conditions leads to an increase in CBF, which may be regionally specific. Studies investigating the effect of hypoxia on CBF have utilized varying gradations and durations of hypoxia and different measuring techniques (transcranial doppler ultrasound or magnetic resonance imaging (MRI)). COX has been shown to significantly contribute to CBF at rest, however during hypoxia research has shown conflicting data on COX contribution to hypoxic CBF. Utilizing arterial spin labeling (ASL), an MRI technique that provides microvascular global and regional perfusion, during hypoxia stimulated CBF and the role of COX. We hypothesized hypoxia will increase CBF non‐uniformly, and COX inhibition with Ketorolac will reduce hypoxic dilation in some, but not all brain regions.Methods6 healthy young adults subjects (24 ± 3 years, 22.4 ± 0.7 BMI, 4 male) were included in this analysis using an institutional review board (IRB)‐approved protocol. Subjects completed an ASL MRI scans (5.5 min each) under the 3 distinct conditions: normoxia, hypoxia, and hypoxia + ketorolac drug infusion. The first ASL scan occurred while the subject breathed ambient air (baseline). Isocapnic hypoxia was then induced by breathing reduced O2 (9‐13%) to reduce arterial saturation to 80‐85% for steady state hypoxia followed by the first hypoxia ASL scan. While hypoxia was maintained, Ketorolac was infused at a rate of 0.495 mg/kg over 3 minutes (average dose 33.9 ± 2.8 mg), the third ASL scan was then completed (hypoxia+ketorolac). ASL analysis included smoothing grey matter, co‐registering and normalizing raw data, brain masking and region of interest processing. Statistics were determined using a Two‐Way Repeated Measures ANOVA with Tukey’s post‐hoc analysis.ResultsData are mean ± SD. SpO2 (98 ± 1%, 82 ± 2%, 82 ± 1%) and ETCO2 (36 ± 1mmHg, 35 ± 2mmHg, 34 ± 2) at baseline, hypoxia, and hypoxia+ketorolac, respectively. Baseline Global CBF (58 ± 15 ml/100g‐1/min‐1) was not significantly different from hypoxia (61 ± 14 ml/100g‐1/min‐1) (p=0.47). Regionally, CBF between baseline and hypoxia were not different in the right/left temporal, occipital, parietal, or frontal lobes (R/L: p=0.47/p=0.98, p=0.59/p=0.49, p=0.46/p=0.63, and p=0.18/0.19, respectively). Ketorolac did not change global CBF during hypoxia (60 ± 17 ml/100g‐1/min‐1) (p=0.96). Regional CBF during hypoxia and hypoxia+ketorolac was not changed in the right/left temporal, occipital, parietal, or frontal lobes (R/L: p=0.96/0.91, p=0.57/0.88, p=0.86/0.99, and p=0.38/0.35, respectively).DiscussionContrary to our hypothesis CBF did not change globally or regionally with hypoxia stimulation. Furthermore, COX inhibition via Ketorolac did not change CBF during hypoxia in any region. This finding corroborates previous studies in animals and macrovascular flow in humans that COX inhibitor Ketorolac acts differently in the brain compared to Indomethacin, despite similar pharmacology. In conclusion, acute hypoxia exposure with Ketorolac did not alter microvascular CBF.

Cerebrovascular changes in neuro-Behcet's disease and neuropsychiatric lupus by transcranial Doppler ultrasonography and magnetic resonance imaging

IntroductionTranscranial Doppler ultrasonography (TCD) is a technique that allows measurement of blood flow from the basal intracerebral vessels. It is relatively inexpensive, non-invasive, can be performed at the bedside, and allows monitoring in acute emergency settings and for prolonged periods with a high temporal resolution, making it ideal for studying the haemodynamics within the intracranial arteries in neuro-Behcet's disease (NBD) and neuro-psychiatric lupus (NPSLE). Our aim was to assess the cerebral haemodynamic patterns in patients with NBD and NPSLE using TCD, while brain lesions were examined using magnetic resonance imaging (MRI). Material and methodsCase–control prospective study of 30 neuro-Behcet's disease patients, 25 neuro-psychiatric lupus patients and 26 healthy age-matched volunteers. All patients and healthy controls were examined by TCD. Only the groups of patients underwent cranial magnetic resonance imaging (MRI). ResultsTranscranial Doppler (TCD) values for middle cerebral artery (MCA), anterior cerebral artery (ACA), posterior cerebral artery (PCA), vertebral artery (VA) and basilar artery (BA) in NBD, NPSLE and control groups were measured. The results showed that there was a significant decrease in mean blood flow velocities in all the arteries examined in NBD and NPSLE patients. There was also a significant increase in the pulsatile index of PCA, VA and BA between NBD and NPSLE patients. The same results were obtained when comparing NBD versus controls. However, there was no significant difference between the NPSLE patients and the control group. The MRI lesions described were parenchymal lesions in 14 patients (46.7%), and vascular lesions in 4 patients (13.3%). Vascular lesions co-existed with parenchymal lesions (mixed lesion). Parenchymal lesions were in white matter (40%), thalamus (26.7%), brain stem (26.7%) and cerebellum (20%). While, in NPSLE, 23 patients were normal (92%) and only two patients had a vascular lesion (8%). ConclusionThere was a significant decrease in mean blood flow and a significant increase in the pulsatile index among both NBD and NPSLE patients, according to the TCD values.

Study Protocol: Multimodal Longitudinal Assessment of Infant Brain Organization and Recovery in Perinatal Brain Injury.

Perinatal brain injury is a primary cause of cerebral palsy, a condition resulting in lifelong motor impairment. Infancy is an important period of motor system development, including development of the corticospinal tract (CST), the primary pathway for cortical movement control. The interaction between perinatal stroke recovery, CST organization, and resultant motor outcome in infants is not well understood. Here, we present a protocol for multimodal longitudinal assessment of brain development and motor function following perinatal brain injury using transcranial magnetic stimulation and magnetic resonance imaging to noninvasively measure CST functional and structural integrity across multiple time points in infants 3 to 24 months of age. We will further assess the association between cortical excitability, integrity, and motor function. This protocol will identify bioindicators of motor outcome and neuroplasticity and subsequently inform early detection, diagnosis, and intervention strategies for infants with perinatal stroke, brain bleeds, and related diagnoses.