Keywords: Blood Vessels, Neurofluids, respiratory effects, CBF, cerebral blood flow, phase contrast, real time phase contrast

Motivation: The hydrodynamic characteristics of arterial venous cerebral blood flow (AVCBF) in different breathing patterns remain insufficiently understood.

Goal(s): Quantifying the effects of free and deep breathing on multiple parameters of CBF using real-time phase contrast MRI.

Approach: We applied RT-PC on 14 healthy volunteers to continuously quantify AVCBF dynamics in the main cerebral vessels during free and deep breathing. A time-domain analysis investigated the influence of breathing change on the AVCBF parameters: mean flow, stroke volume, cardiac period.

Results: Deep-breathing decreased global AVCBF dynamics. Mean flows, stroke volumes and cardiac periods decreased but their percentage change between inspiratory and expiratory periods increased.

Impact: This study quantified the effects of free- and deep-breathing on cerebral blood flow dynamics. It should contribute to a better understanding of cerebral hemodynamics and its relation with breathing, providing a valuable reference for clinical applications and physiological studies.

Keywords: Blood Vessels, CEST & MT, Cerebrovascular disease

Motivation: Assessing alterations of the brain microenvironment in patients with moyamoya disease after revascularization (MMD) would develop optimal postoperative management and improve the prognosis.

Goal(s): This study aimed to explore alterations of amide proton transfer weighted (APTw) signal in patients with MMD after receiving revascularization surgery.

Approach: MMD patients who underwent unilateral revascularization surgery were prospectively collected. Baseline computed tomography perfusion (CTP) and APTw imaging were performed. Patients were followed up with CTP and APTw imaging about 1 year after revascularization.

Results: APTw values in both surgical and contralateral hemispheres at follow-up were found to be significantly higher than those at baseline.

Impact: APTw imaging is a potential assessment tool to quantitatively evaluate alterations of acid-base metabolism in the brain microenvironment of patients with MMD after revascularization, which provides additional information to help neurosurgeons develop optimal postoperative management and follow-up protocols for MMD.

Keywords: Blood Vessels, Velocity & Flow, Cerebrovascular disease, moyamoya angiopathy

Motivation: Current evidence is insufficient to help better understand the interactions between hemodynamics of carotid siphons in moyamoya angiopathy (MMA) and outcomes of revascularization.

Goal(s): To evaluate hemodynamic alterations of carotid siphons after revascularization for MMA using 4D Flow MRI and to explore its association with outcomes.

Approach: MMA patients receiving revascularization were prospectively enrolled. We used VesselExplorer2 software to analyze 4D Flow MRI data and measure hemodynamic parameters of carotid siphons. Relationships between hemodynamic parameters of carotid siphons and surgical outcomes were explored.

Results: Flow_mean and Flow_max of bilateral ICAs in MMA decreased at follow-up, which was associated with outcomes of revascularization surgery.

Impact: We identified new hemodynamic parameters that might be used to predict the prognosis of MMA. 4D Flow MRI is a promising tool for quantitatively detecting hemodynamics in intracranial vessels of MMA patients, providing valuable hemodynamic parameters for evaluating surgical outcomes.

Keywords: Blood Vessels, Modelling

Motivation: MRI is increasingly used to investigate vascular pathology in neurodegenerative disease. The origin of the MRI signal, however, often remains elusive. This study models pulsatile blood flow aiming to characterize vascular pulsation’s impact on MRI signal formation in advanced sequences.

Goal(s): To create a realistic model of pulsatile blood flow in microvasculature.

Approach: Static and pulsatile flow are simulated in a simplified and a more realistic synthetically generated vessel model using 1D approximations of governing equations.

Results: Pulsatile flow simulations in simplified networks with realistic inflow wave forms yield realistic deformation characteristics. Realistic pressure and flow distributions are achieved in extensive microvascular networks.

Impact: By providing realistic voxel-scale vascular simulation models capable of quantifying physiological parameters such as CBV and vessel deformation due to pulsatility, contribution of microvascular pulsations to MRI signal and cerebral waste clearance may be explored in the future.

Keywords: Blood Vessels, Stroke, Acute ischemic stroke,Multimodal Scan,Time Efficiency

Motivation: The matter of time efficiency for both CT and MRI remains a topic of ongoing debate.

Goal(s): To provide an objective comparison of time efficiency between CT multimodal and MRI multimodal scans in patients with acute ischemic stroke in the late time window.

Approach: Efficiency in terms of time was compared between AIS patients who underwent CT scans and those who underwent MRI scans.

Results: The evaluation time for the MRI multimodal scan was found to be shorter than that of CT. MRI scans were recommended for use during the night shift. Furthermore, more experienced technicians had shorter scanning times.

Impact: Implementing this approach can streamline the scanning procedure for radiology departments when dealing with acute stroke patients, aid in the training of technicians, and recommend a preference for MRI scans during nighttime shifts.

Keywords: Blood Vessels, Neurodegeneration, Cerebral Small Vessel Disease

Motivation: The motivation behind this study was to delve deeper into the amygdala subregion changes in Cerebral Small Vessel Disease (CSVD) and how these changes correlate with cognitive impairment.

Goal(s): The primary goal was to determine whether specific amygdala subregions could serve as early indicator for cognitive impairment in CSVD, thereby aiding in early diagnosis and intervention.

Approach: Combined 3T MRI neuroimaging with cognitive assessments and focused statistical evaluation of amygdala subregions

Results: Our study revealed significant volume reductions in specific amygdala subregions among CSVD group, with pronounced atrophy observed in the left cortical nucleus.

Impact: This research introduces a novel indicator that utilizes neuroimaging techniques for the early prediction of CSVD progression and associated cognitive impairment, which could significantly enhance the precision of diagnostics and inform effective management strategies for CSVD.

Keywords: Blood Vessels, Blood vessels

Motivation: The annual stroke risk of symptomatic middle cerebral artery (MCA) stenosis patients is more than four times that of asymptomatic patients, and doctors need to identify these two types for personalized treatment

Goal(s): We aim to investigate whether there is a difference in the number of stems and branches of the Lenticulostriate Artery (LSA) between symptomatic and asymptomatic unilateral MCAstenosis patients at 7T

Approach: Count the number of LSA stems and branches in the patient's cerebral hemisphere using 7T TOF MRA

Results: :We found that the number of LSA branches varies between symptomatic and asymptomatic patients

Impact: LSA may serve as an imaging indicator for early diagnosis and personalized treatment of different types of MCA stenosis patients.

Keywords: Blood Vessels, Brain

Motivation: It is important to understand the mechanisms underlying middle cerebral artery stenosis and detect altered vascular function prior to the alteration in brain parenchyma. 7T MRI, benefited from much increased signal-to-noise ratio

Goal(s): Evaluate vascular function in the affected and healthy middle cerebral arteries of patients with unilateral middle cerebral arterial stenosis. 

Approach: 7T-MRI to assess blood flow velocities and pulsatility indices (PI). 

Results: Flow velocity and PI in the middle cerebral artery were lower on the affected side than on the healthy side. These markers will facilitate mechanistic and interventional studies of middle cerebral artery stenosis.

Impact: Flow velocity and PI were lower on the affected side than on the healthy side in patients with middle cerebral artery stenosis. These findings may improve the understanding of middle cerebral artery stenosis pathogenesis.

Keywords: Blood Vessels, Blood vessels, 7T MRI，MR angiography, middle cerebral artery occlusion

Motivation: Territory supplied by lenticulostriate arteries includes deep subcortical grey matter nucleus which pose vast influence on neurological function. 

Goal(s): To elaborate the modification of lenticulostriate arteries when middle cerebral artery occluded.

Approach: Patients with MCA occlusion were performed 7T time-of-flight MR angiography with voxel size of isotropic 0.3mm.

Results: Origination of LAS were modified to originated from the proximal end of occluded segment in 64.3%. While their morphometrical features were identical with the normal contralateral side LSA.

Impact: The finding may be helpful for the protection of LSA in endovascular procedure, and provide critical knowledge about the angiogenesis of middle cerebral artery. Future large sample size 7T MRI study is warranted.

Keywords: Blood Vessels, Quantitative Susceptibility mapping, cerebral small vessel disease, hippocampus, iron deposition, cognition.

Motivation: The deposition of excess iron in subcortical nuclei may be linked to the burden of cerebral small vessel disease (CSVD) and could contribute to decreased cognitive performance. 

Goal(s): To investigate the relationship between iron deposition in subcortical nuclei and CSVD severity, as well as cognitive impairment.

Approach: Brain iron deposition was assessed by quantitative susceptibility mapping (QSM).

Results: Susceptibility in the posterior part of the right hippocampus (pHIP-R) was negatively correlated with cognitive performance and positively correlated with CSVD severity.

Impact: Iron deposition in pHIP-R could be an early biomarker of CSVD-related cognitive impairment in future research, providing new evidence for investigating the mechanism of cognitive impairment in CSVD.

Keywords: Blood Vessels, CEST & MT

Motivation: Identifying the dynamic changes of the brain microenvironment in patients with moyamoya disease (MMD) would improve disease management and treatment.

Goal(s): To explore the alteration of amide proton transfer weighted (APTw) signal in patients with MMD during the follow-up.

Approach: MMD patients who had not received revascularization were prospectively included. All patients underwent cranial computed tomography perfusion (CTP) and APTw imaging at baseline and at follow-up.

Results: APTw signal in bilateral internal carotid arteries blood supply area significantly increased in MMD patients without surgery during follow-up, and the change of APTw signal was more sensitive than that of CTP.

Impact: APTw imaging could reflect dynamic alterations of the brain microenvironment of patients with MMD over time, and the changes of APTw signal were more sensitive than CTP, which is helpful to improve clinical management.

Keywords: Blood Vessels, Atherosclerosis

Motivation: 4D flow MRI is a promising diagnosis tool for studies on intracranial atherosclerosis.  Since pressure drops across stenoses could be used for diagnosis, a robust non-invasive technique for regional pressure variations is of great value.

Goal(s): To validate stenotic pressure drops estimated using Virtual Work Energy Relative Pressure (vWERP) while taking into account spatial resolution dependency and turbulence.

Approach: Relative pressure was estimated at multiple locations in two different stenoses using vWERP and compared with gold-standad catheter measurements. Additionally, tubulent kinetic energy (TKE) was determined.

Results: vWERP provided robust estimates of relative pressure and demonstrated excellent agreement with catheter measurements despite high TKE.

Impact: This abstract demonstrates a versatile setup to estimate relative pressure in stenoses at pulsatile flow conditions. The influence of spatial resolution and turbulences were investigated. The results may help to implement non-invasive pressure estimations to the clinical routine. 

Keywords: Blood Vessels, Blood vessels

Motivation:  The association between cognitive impairment and  lenticulostriate arteries (LSAs) in patients with CSVD remains uncertain.

Goal(s): This study aims to investigate the relationship between the imaging characteristics of lenticulostriate arteries (LSAs) and cognitive function in patients with sporadic CSVD.

Approach: Forty-seven CSVD patients and 28 healthy people were prospectively recruited. According to the MoCA score and years of education, they were divided into the Non-VCI group and the VCI group .

Results: The decrease in the number of LSA was an independent risk factor for VCI in CSVD patients . The number and total length of LSA were significantly correlated with MMSE and MoCA score.

Impact: LSAs is associated with overall cognitive dysfunction in CSVD patients, and the number of LSAS is an independent risk factor for VCI in CSVD patients.

Keywords: Blood Vessels, Velocity & Flow, small vessel disease, vascular function, cerebral blood flow

Motivation: Given the limitations in resolution and sensitivity, in vivo studies of microvascular function in small vessel disease(SVD) have been notably scarce.  

Goal(s): Advanced cerebral-hemodynamic techniques have made it possible to unveil functional alterations in SVD explored in this study.

Approach: Utilizing a comprehensive microvascular-functional measurement, including 7T-high-resolution phase-contrast and 3T-ASL modeling, we examined the hemodynamics change and its associations with severity of SVD reflected by multidomain cognitive impairments.

Results: Flow velocity in lenticulostriate arteries emerged as the most sensitive indicator, while ASL-derived arterial-transit-time(ATT) and cerebral-blood-flow(CBF), reflecting capillary functions, exhibited reduced sensitivity. Our exploration unveiled insights into microvascular pathology and compensatory mechanisms in SVD.

Impact: Utilizing cutting-edge cerebrovascular MRI techniques, multiple microvascular hemodynamic metrics provide novel insights into small vessel disease(SVD) pathology in-vivo, revealing the functional damage and compensatory mechanisms.
Also, flow velocity in small arteries is proved a promising imaging marker for SVD progression.

Keywords: Blood Vessels, White Matter, Small vessel disease, white matter hyperintensities, diffusion MRI, pulsatility, vascular reactivity, progressive white matter injury, CADASIL

Motivation: Impaired blood flow velocity and pulsatility on 7T MRI are associated with white matter injury in cerebral small vessel disease (cSVD) cross-sectionally, but it is unclear whether it relates to injury progression. 

Goal(s): To assess if small vessel dysfunction is associated with markers of progressive white matter injury in monogenic cSVD.

Approach: Small vessel function was measured on 7T MRI in monogenic cSVD. White matter injury (white matter hyperintensities, peak-skeletonized mean diffusivity) was measured with 3T MRI on baseline and two-year follow-up.

Results: There were no associations between small vessel dysfunction and white matter injury progression in monogenic cSVD.

Impact: Whole-brain white matter injury progression cannot be explained by small vessel function. Local white matter injury progression might be linked with small vessel function and should be assessed in the future with voxelwise studies.

Keywords: Blood Vessels, Neurodegeneration, Myelin Water Imaging

Motivation: Thrombotic Thrombocytopenic Purpura patients suffer from high risk of cognitive related complications post-remission that can decrease quality-of-life and in some cases death.

Goal(s): We investigate a new treatment drug Caplacizumab to determine whether it can reduce neurocognitive burden.

Approach: We use quantitative MRI and CT-perfusion to investigate patients that have received Caplacizumab to patients that have not. MRI and CT data look at a variety of different metrics to investigate brain health.

Results: Preliminary results from CT-perfusion indicate better blood brain barrier recovery in Caplacizumab group, which may decrease cognitive burden. MRI results show significant decrease of myelin in patients without Caplacizumab.

Impact: The results of this study can open the door for a new treatment for Thrombotic Thrombocytopenic Purpura patients that may ensure they do not suffer from cognitive decline or cerebrovascular disease related death.