Role of the vessel morphology on the lenticulostriate arteries hemodynamics during atrial fibrillation: A CFD-based multivariate regression analysis.

BACKGROUND AND OBJECTIVE: Atrial fibrillation (AF) is the most common cardiac arrhythmia, inducing accelerated and irregular beating. Beside well-known disabling symptoms - such as palpitations, reduced exercise tolerance, and chest discomfort - there is growing evidence that an alteration of deep cerebral hemodynamics due to AF increases the risk of vascular dementia and cognitive impairment, even in the absence of clinical strokes. The alteration of deep cerebral circulation in AF represents one of the least investigated among the possible mechanisms. Lenticulostriate arteries (LSAs) are small perforating arteries mainly departing from the middle cerebral artery (MCA) and susceptible to small vessel disease, which is one of the mechanisms of subcortical vascular dementia development. The purpose of this study is to investigate the impact of different LSAs morphologies on the cerebral hemodynamics during AF. METHODS: By combining a computational fluid dynamics (CFD) analysis of LSAs with 7T high-resolution magnetic resonance imaging (MRI), we performed different CFD-based multivariate regression analyses to detect which geometrical and morphological vessel features mostly affect AF hemodynamics in terms of wall shear stress. We exploited 17 cerebral 7T-MRI derived LSA vascular geometries extracted from 10 subjects and internal carotid artery data from validated 0D cardiovascular-cerebral modeling as inflow conditions. RESULTS: Our results revealed that few geometrical variables - namely the size of the MCA and the bifurcation angles between MCA and LSA - are able to satisfactorily predict the AF impact. In particular, the present study indicates that LSA morphologies exhibiting markedly obtuse LSA-MCA inlet angles and small MCA size downstream of the LSA-MCA bifurcation may be more prone to vascular damage induced by AF. CONCLUSIONS: The present MRI-based computational study has been able for the first time to: (i) investigate the net impact of LSAs vascular morphologies on cerebral hemodynamics during AF events; (ii) detect which combination of morphological features worsens the hemodynamic response in the presence of AF. Awaiting necessary clinical confirmation, our analysis suggests that the local hemodynamics of LSAs is affected by their geometrical features and some LSA morphologies undergo greater hemodynamic alterations in the presence of AF.

Correlation Between Cognitive Impairment and Lenticulostriate Arteries: A Clinical and Radiomics Analysis.

Lenticulostriate arteries (LSA) are potentially valuable for studying vascular cognitive impairment. This study aims to investigate correlations between cognitive impairment and LSA through clinical and radiomics features analysis. We retrospectively included 102 patients (mean age 62.5±10.3 years, 60 males), including 58 with mild cognitive impairment (MCI) and 44 with moderate or severe cognitive impairment (MSCI). The MRI images of these patients were subjected to z-score preprocessing, manual regions of interest (ROI) outlining, feature extraction (pyradiomics), feature selection [max-relevance and min-redundancy (mRMR), least absolute shrinkage and selection operator (LASSO), and univariate analysis], model construction (multivariate logistic regression), and evaluation [receiver operating characteristic curve (ROC), decision curve analysis (DCA), and calibration curves (CC)]. In the training dataset (71 patients, 44 MCI) and the test dataset (31 patients, 17 MCI), the area under curve (AUC) of the combined model (training 0.88 [95% CI 0.78, 0.97], test 0.76 [95% CI 0.6, 0.93]) was better than that of the clinical model and the radiomics model. The DCA results demonstrated the highest net yield of the combined model relative to the clinical and radiomics models. In addition, we found that LSA total vessel count (0.79 [95% CI 0.08, 1.59], P = 0.038) and wavelet.HLH_glcm_MCC (-1.2 [95% CI -2.2, -0.4], P = 0.008) were independent predictors of MCI. The model that combines clinical and radiomics features of LSA can predict MCI. Besides, LSA vascular parameters may serve as imaging biomarkers of cognitive impairment.

Evaluating Middle Cerebral Artery Plaque Characteristics and Lenticulostriate Artery Morphology Associated With Subcortical Infarctions at 7T MRI.

BACKGROUND: Lenticulostriate artery (LSA) obstruction is a potential cause of subcortical infarcts. However, MRI LSA evaluation at 3T is challenging. PURPOSE: To investigate middle cerebral artery (MCA) plaque characteristics and LSA morphology associated with subcortical infarctions in LSA territories using 7-T vessel wall MRI (VW-MRI) and time-of-flight MR angiography (TOF-MRA). STUDY TYPE: Prospective. POPULATION: Sixty patients with 80 MCA atherosclerotic plaques (37 culprit and 43 non-culprit). FIELD STRENGTH/SEQUENCE: 7-T with 3D TOF-MRA and T1-weighted 3D sampling perfection with application-optimized contrast using different flip angle evolutions (SPACE) sequences. ASSESSMENT: Plaque distribution (superior, inferior, ventral, or dorsal walls), LSA origin involvement, LSA morphology (numbers of stems, branches, and length), and plaque characteristics (normalized wall index, maximal wall thickness, plaque length, remodeling index, intraplaque hemorrhage, and plaque surface morphology (regular or irregular)) were assessed. STATISTICAL TESTS: Least absolute shrinkage and selection operator regression, generalized estimating equations regression, receiver operating characteristic curve, independent t-test, Mann-Whitney U test, Chi-square test, Fisher's exact test, and intra-class coefficient. A P value <0.05 was considered statistically significant. RESULTS: Plaque irregular surface, superior wall plaque, longer plaque length, LSA origin involvement, fewer LSA stems, and shorter total and average lengths of LSAs were significantly associated with culprit plaques. Multivariable logistic analysis confirmed that LSA origin involvement (OR, 28.51; 95% CI, 6.34-181.02) and plaque irregular surface (OR, 8.32; 95% CI, 1.41-64.73) were independent predictors in differentiating culprit from non-culprit plaques. A combination of LSA origin involvement and plaque irregular surface (area under curve = 0.92; [95% CI, 0.86-0.98]) showed good performance in identifying culprit plaques, with sensitivity and specificity of 86.5% and 86.0%, respectively. DATA CONCLUSION: 7-T VW-MRI and TOF-MRA can demonstrate plaque involvement with LSA origins. MCA plaque characteristics derived from 7-T VW-MRI showed good diagnostic accuracy in determining the occurrence of subcortical infarctions. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 3.

The "island sign" on diffusion-weighted imaging predicts early neurological deterioration in penetrating artery territory infarctions: a retrospective study.

BACKGROUND: Early neurological deterioration (END) sometimes occurs in patients with penetrating artery territory infarction (PATI) and leads to poor prognosis. In this study, we analyzed clinical and neuroimaging characteristics of PATI, and focused on the infarct patterns on diffusion-weighted imaging (DWI). We tried to investigate whether the "island sign" pattern is associated with END. METHODS: We enrolled consecutive patients admitted with acute PATI within 48 h after onset from May 2020 to July 2022. They were divided into with and without the "island sign" pattern on DWI. According to infarct location, all the patients were classified into two groups: the territories of the lenticulostriate arteries (LSA) and paramedian pontine arteries (PPA). The patients in each group were further divided into two groups according to whether they developed END or not. Through analyzing the clinical and neuroimaging characteristics of the patients, we tried to identify the factors that might associated with the "island sign" pattern and the potential predictors of END within the LSA and PPA groups. RESULTS: Out of the 113 patients enrolled in this study, END was found in 17 patients (27.9%) in the LSA group and 20 patients (38.5%) in the PPA group. The "island sign" was found in 26 (23%) patients. In the multivariate analysis, the independent predictors of END in the LSA group were the "island sign" (OR 4.88 95% CI 1.03-23.2 P = 0.045) and high initial National Institute of Health Stroke Scale (NIHSS) (OR 1.79 95% CI 1.08-2.98 P = 0.024) and in the PPA group was the presence of lesions extending to the ventral pontine surface (OR 7.53 95% CI 1.75-32.37 P = 0.007). CONCLUSIONS: The predictive factors for END were different in the LSA and PPA groups. The "island sign" was particularly associated with END in the LSA group.

Impaired damping of cerebral blood flow velocity pulsatility is associated with the number of perivascular spaces as measured with 7T MRI.

Arterial walls stiffen with age, cardiovascular risk factors, and various vascular diseases, which may lead to less damping of the arterial blood flow pulse, subsequent microvascular damage, and enlarged perivascular spaces (PVS). However, the exact interplay between these processes is unclear. This study aimed to investigate the relation between blood flow velocity pulsatility in the small lenticulostriate arteries and their supplying middle cerebral artery and the respective damping factor (DF), with the number of MRI-visible PVS in elderly subjects. Blood flow velocity waveforms were obtained in 45 subjects (median age [range]: 64 [48-81] years, 47% male) using 7T MRI. PVS were scored in the basal ganglia (BG) and centrum semiovale (CSO). Spearman correlation analyses were used to determine associations of the blood flow pulsatility and the DF, with PVS score, adjusted for age and sex. We found a significant association between a lower DF and a higher number of PVS in the BG (rs = -0.352, P = 0.021), but not in the CSO. This finding supports the supposed pathophysiological mechanism in which excessive kinetic energy deposition leads to damage of small perforating arteries and contributes to the enlargement of PVS at the level of the BG, but possible other pathways might also be of influence.

1D versus 3D blood flow velocity and pulsatility measurements of lenticulostriate arteries at 7T MRI.

PURPOSE: 7T MRI enables measurements of blood flow velocity waveforms in small, perforating cerebral arteries. As these vessels can be tortuous, acquisition methods sensitive to flow in only one direction may not be sufficient to accurately determine the dynamic blood flow velocity. In this study, we compared 1D with 3D velocity encoding to measure the blood flow velocity and pulsatility in the lenticulostriate arteries (LSAs). METHODS: Blood flow velocity waveforms were measured in the LSAs of 18 subjects (age range: 20-74 years) using prospectively gated single-slice phase contrast (PC) MRI at 7T. For each subject, blood flow velocity waveforms were acquired in a single slice with one velocity encoding as well as three orthogonal velocity encodings. The peak velocity and pulsatility index (PI) were determined in the largest, perpendicularly planned LSA, one obliquely planned LSA and three smaller LSAs. The peak velocity and PI were compared between 1D and 3D measurements using Bland-Altman analysis, with the 95% limits of agreement (LOA) taken into account. RESULTS: For the largest, perpendicularly planned LSA, the peak velocity was slightly lower (0.2 cm/s, 1.7%) for 1D compared to 3D measurements, with an LOA range from the mean difference of (-0.27;0.27). The PI was slightly higher (0.01, 1.6%) for the 1D measurement, and an LOA range from the mean difference in PI of (-0.045;0.045). The obliquely planned LSA and three smaller LSAs demonstrated larger deviations (range mean percentage difference: 3.9-8.2%). CONCLUSION: 1D velocity encoding using 2D PC MRI provides sufficiently accurate dynamic velocity and pulsatility measurements in slices perpendicularly planned to single, large LSAs compared to 3D velocity encoding, while increasing errors are obtained with obliquely planned slices. A greater error is indicated when measuring multiple (possibly tortuous or obliquely planned) smaller LSAs in one scan using one-directional single-slice PC MRI.

Comparative anatomy of the middle cerebral artery, rhinal and endorhinal sulci, piriform lobe, entorhinal cortex, olfactory tubercule, anterior perforate substance, and hippocampus: A dissection study.

The literature describing the complex anatomy of the middle cerebral artery (MCA), lenticulostriate arteries, and recurrent artery of Heubner, does not discuss the comparative anatomy of the cerebrum, MCA, the recurrent artery of Heubner, and the relationship of the MCA with the rhinal sulci. The entorhinal literature does not detail the comparative anatomic modification of the rhinal and endorhinal sulci, piriform lobe and the hippocampus's compressed positional change in the temporal lobe. This investigation's objectives were to analyze the comparative anatomic modifications of the cerebrum, the MCA, lenticulostriate arteries, recurrent artery of Heubner, olfactory tubercule, anterior perforate substance, rhinal sulcus, endorhinal sulcus, piriform lobe, entorhinal cortex, and hippocampus. Brain dissections of adult iguana, rabbit, sheep, cat, dog, macaque, human and human fetal specimens were analyzed. The MCA branches enter the striate nuclei via the endorhinal sulcus, with few branches present in the rhinal sulcus. Modifications of the cerebrum, with the development of gyri and sulci and opercula covering the insula, changes the linear surface configuration of the MCA into a tridimensional one. Similar changes are present in human fetal specimens. The cerebral neocortical expansion changes the position of the rhinal and endorhinal sulci, their relationship with the MCA, the size of the olfactory tubercule, the position and size of the piriform lobe, and the diagonal course of the lenticulostriates and recurrent artery of Heubner. The hippocampus becomes compressed in the inferomedial region of the human temporal lobe. The lenticulostriate arteries are likely the first developed component of the MCA.

As artérias lenticuloestriadas podem interferir na extensão da ressecção tumoral e sobrevida nos gliomas da ínsula? / Can lenticulostriated arteries interfere with the extent of tumor resection and survival in insula gliomas?

Introdução: Os gliomas são tumores encefálicos e da medula espinhal que se originam nas células gliais e cuja progressão invade o tecido cerebral adjacentee e dentre eles um dos mais desafiadores são localizados no lobo cerebral da ínsula. Estas artérias irrigam estruturas nobres e sua lesão pode produzir danos sensitivos, motores e de linguagem. Objetivo: Descrever o impacto da extensão da ressecção, sobrevida global e dos resultados funcionais após a cirurgia dos gliomas insulares, quando estes tumores estejam ou não envolvidos pelas artérias lenticuloestriadas. Métodos: Revisão integrativa nas plataformas virtuais em português e inglês, buscando AND ou OR dados através dos seguintes descritores "Gliomas da ínsula, Mapeamento cerebral, Artérias lenticuloestriadas". A busca inicial foi baseada no título e/ou resumo. Decididos os trabalhos incluíveis foi realizada a leitura na íntegra dos textos. Ao total foram estudados 55 artigos. Resultados: O lobo da ínsula fica "escondido" pela sobreposição dos lobos frontal, parietal e temporal. Para alcançá-lo pode-se realizar as abordagens transsilviana ou transcortical. Ocorre que ao chegar na ínsula visualiza-se significativa ramificação constituída pelas artérias lenticuloestriadas, cuja manipulação pode determinar déficit neurológico e, ao se aprofundar no córtex insular, depara-se com outras estruturas tão importantes quanto a própria ínsula. O conhecimento anatômico das artérias lenticuloestriadas e suas relações é de fundamental importância para a ressecção de glioma insular, pois o comprometimento delas e da artéria cerebral média podem determinar a isquemia dos núcleos da base e da cápsula interna. Conclusão: O tratamento dos gliomas insulares permanece como grande desafio. Devido à sua localização e possibilidade de desenvolvimento de déficits neurológicos na manipulação cirúrgica é necessário não somente conhecer sua localização topográfica, mas também a íntima relação vascular com as artérias lenticuloestriadas. O envolvimento delas pelo tumor possui implicações na sobrevida e na preservação da função neurológica. O conhecimento detalhado da anatomia da região é fundamental para diminuir complicações que afetem grandemente a qualidade de vida dos pacientes.

Introduction: Gliomas are brain and spinal cord tumors that originate in glial cells and whose progression invades the adjacent brain tissue and among them one of the most challenging are located in the cerebral lobe of the insula. These arteries supply noble structures and their damage can cause sensory, motor and language damage. Objective: To describe the impact of the extent of resection, overall survival and functional results after surgery for insular gliomas, when these tumors are or are not involved by lenticulostriate arteries. Methods: Integrative review on virtual platforms in Portuguese and English, searching for AND or OR data using the following descriptors "Insula gliomas, Brain mapping, Lenticulostriate arteries". The initial search was based on the title and/or abstract. Once the included works were decided, the texts were read in full. In total, 55 articles were studied. Results: The insula lobe is "hidden" by the overlap of the frontal, parietal and temporal lobes. To achieve this, transsylvian or transcortical approaches can be performed. It turns out that when arriving at the insula, a significant branch made up of lenticulostriate arteries is seen, the manipulation of which can cause neurological deficits and, when going deeper into the insular cortex, one comes across other structures as important as the insula itself. Anatomical knowledge of the lenticulostriate arteries and their relationships is of fundamental importance for the resection of insular glioma, as their involvement and that of the middle cerebral artery can determine ischemia of the basal ganglia and internal capsule. Conclusion: The treatment of insular gliomas remains a major challenge. Due to its location and the possibility of developing neurological deficits during surgical manipulation, it is necessary not only to know its topographic location, but also the intimate vascular relationship with the lenticulostriate arteries. Their involvement by the tumor has implications for survival and preservation of neurological function. Detailed knowledge of the region's anatomy is essential to reduce complications that greatly affect patients' quality of life.

Sensitivity of three-dimensional time-of-flight 3.0 ​T magnetic resonance angiography in visualizing the number and course of lenticulostriate arteries in patients with insular gliomas.

Background: Neurosurgical resection of insular gliomas is complicated by the possibility of iatrogenic injury to the lenticulostriate arteries (LSAs) and is associated with devastating neurological complications, hence the need to accurately assess the number of LSAs and their relationship to the tumor preoperatively. Methods: The study included 24 patients with insular gliomas who underwent preoperative 3D-TOF MRA to visualize LSAs. The agreement of preoperative magnetic resonance imaging with intraoperative data in terms of the number of LSAs and their invasion by the tumor was assessed using the Kendall rank correlation coefficient and Cohen's Kappa with linear weighting. Agreement between experts performing image analysis was estimated using Cohen's Kappa with linear weighting. Results: The number of LSAs arising from the M1 segment varied from 0 to 9 (mean 4.3 â€‹± â€‹0.37) as determined by 3D-TOF MRA and 2-6 (mean 4.25 â€‹± â€‹0.25) as determined intraoperatively, κ â€‹= â€‹0.51 (95% CI: 0.25-0.76) and τ â€‹= â€‹0.64 (p â€‹< â€‹0.001). LSAs were encased by the tumor in 11 patients (confirmed intraoperatively in 9 patients). LSAs were displaced medially in 8 patients (confirmed intraoperatively in 8 patients). The tumor partially involved the LSAs and displaced them in 5 patients (confirmed intraoperatively in 7 patients), κ â€‹= â€‹0.87 (95% CI: 0.70-1), τ â€‹= â€‹0.93 (p â€‹< â€‹0.001). 3D-TOF MRA demonstrated high sensitivity (100%, 95% CI: 0.63-1) and high specificity (86.67%, 95% CI: 0.58-0.98) in determining the LSA-tumor interface. Conclusions: 3D-TOF MRA at 3T demonstrated sensitivity in determining the LSA-tumor interface and the number of LSAs in patients with insular gliomas.

Navigated 3D-ultrasound power Doppler and visualization of lenticulostriate arteries during resections of insular gliomas.

•Preservation of LSAs is extremely important during resections of insular gliomas.•Navigated 3D-US power Doppler may enable intraoperative visualization of LSAs.•Quality of ultrasound scanner is important when LSAs should be visualized.•Reliability of LSAs depiction by 3D-US power Doppler is still investigated.

Incidence of ischemic complications and technical nuances of arteries preservation for insular gliomas resection.

Introduction: Insular gliomas have complex anatomy and microvascular supply that make resection difficult. Furthermore, resection of insular glioma is associated with a significant risk of postoperative ischemic complications. Thus, this study aimed to assess the incidence of ischemic complications related to insular glioma resection, determine its risk factors, and describe a single surgeon's experience of artery-preserving tumor resection. Methods: We enrolled 75 consecutive patients with insular gliomas who underwent transcortical tumor resection. Preoperative and postoperative demographic, clinical, radiological [including diffusion-weighted imaging (DWI)], intraoperative neurophysiological data, and functional outcomes were analyzed. Motor evoked potentials (MEPs) and radiological characteristics like the relationship between the proximal segment of the lateral lenticulostriate arteries (LLSAs) and the tumor, the flat inner edge sign (the inner edge of the insular glioma is well-defined) or obscure inner edge sign, the distance between the lesion and posterior limb of the internal capsule and the invasion of the superior limiting sulcus by the tumor were analyzed. Strategies such as "residual triangle," "basal ganglia outline reappearance," and "sculpting" technique were used to preserve the LLSAs and the main branches of M2 for maximal tumor resection according to the Berger-Sinai classification. Results: Postoperative DWI showed acute ischemia in 44 patients (58.7%). Moreover, nine patients (12%) had developed new motor deficits, as determined by the treating neurosurgeons. The flat inner edge sign [odds ratio (OR), 0.144; 95% confidence interval (CI), 0.024-0.876) and MEPs (>50%) (OR, 18.182; 95% CI, 3.311-100.00) were significantly associated with postoperative core ischemia, which affected the posterior limb of the internal capsule or corona radiata. Conclusions: Insular glioma resection was associated with a high incidence of ischemia, as detected by DWI, as well as new motor deficits that were determined by the treating neurosurgeons. Insular glioma patients with obscure inner edge signs and intraoperative MEPs decline >50% had a higher risk of developing core ischemia. With our strategies, maximal safe resection of insular gliomas may be achieved.

Optimization of undersampling parameters for 3D intracranial compressed sensing MR angiography at 7 T.

PURPOSE: 3D time-of-flight MRA can accurately visualize the intracranial vasculature but is limited by long acquisition times. Compressed sensing reconstruction can be used to substantially accelerate acquisitions. The quality of those reconstructions depends on the undersampling patterns used. In this work, we optimize sets of undersampling parameters for various acceleration factors of Cartesian 3D time-of-flight MRA. METHODS: Fully sampled datasets, acquired at 7 Tesla, were retrospectively undersampled using variable-density Poisson disk sampling with various autocalibration region sizes, polynomial orders, and acceleration factors. The accuracy of reconstructions from the different undersampled datasets was assessed using the vessel-masked structural similarity index. Identified optimal undersampling parameters were then evaluated in additional prospectively undersampled datasets. Compressed sensing reconstruction parameters were chosen based on a preliminary reconstruction parameter optimization. RESULTS: For all acceleration factors, using a fully sampled calibration area of 12 × 12 k-space lines and a polynomial order of 2 resulted in the highest image quality. The importance of parameter optimization of the sampling was found to increase for higher acceleration factors. The results were consistent across resolutions and regions of interest with vessels of varying sizes and tortuosity. The number of visible small vessels increased by 7.0% and 14.2% when compared to standard parameters for acceleration factors of 7.2 and 15, respectively. CONCLUSION: The image quality of compressed sensing time-of-flight MRA can be improved by appropriate choice of undersampling parameters. The optimized sets of parameters are independent of the acceleration factor and enable a larger number of vessels to be visualized.

Adult Pilocytic Astrocytoma in the insula: Case report and review of the literature.

INTRODUCTION: and Importance: Adult Pilocytic Astrocytomas (APA) are infrequent low grade tumors. While supratentorial APA is considered rare, insular APA is extremely rare. CASE PRESENTATION: We present a case of pure insular APA along with surgical outcomes. Tractography and functional MRI were obtained pre-operatively. The patient underwent neuro-navigation guided microsurgical resection with sub-cortical white matter mapping, utilizing Intra-operative MRI guidance. The Sylvain fissure was opened to secure the M3 branches, and near total resection was achieved. CLINICAL DISCUSSION: APA in the insula is a very rare presentation and is considered challenging. Its proximity to the middle cerebral and lenticulostriate arteries, motor areas, and language areas makes accessing and resecting the tumor challenging. A multidisciplinary approach by an experienced team is needed to plan the management of young adult patients and reach the best outcomes. CONCLUSION: Implementing microsurgical techniques, modern imaging modalities and intraoperative mapping helps to achieve maximal safe resection without risking functions.

Complication avoidance: resection of the insular glioma complicated by iatrogenic injury to the lenticulostriate artery.

BACKGROUND: Neurosurgical resection of insular gliomas is complicated by the risk of iatrogenic injury to lenticulostriate arteries (LSAs). METHOD: We provide a description, figures, and a video to illustrate the clinical case in which the LSA was damaged during the resection of insular glioma. Cadaveric dissection from our anatomical laboratory and our 3D anatomical model provided relevant surgical anatomy of the insula. CONCLUSION: Proximal dissection of the Sylvian fissure up to the most lateral LSA, the emergence of the beige putamen, and the lenticulostriate veins are anatomic landmarks that allow reducing the risk of damaging the intraparenchymatous segment of the LSAs.

High-Resolution Neurovascular Imaging at 7T: Arterial Spin Labeling Perfusion, 4-Dimensional MR Angiography, and Black Blood MR Imaging.

Ultrahigh field offers increased resolution and contrast for neurovascular imaging. Arterial spin labeling methods benefit from an increased intrinsic signal-to-noise ratio of MR imaging signal and a prolonged tracer half-life at ultrahigh field, allowing the visualization of layer-dependent microvascular perfusion. Arterial spin labeling-based time-resolved 4-dimensional MR angiography at 7T provides a detailed depiction of the vascular architecture and dynamic blood flow pattern with high spatial and temporal resolutions. High-resolution black blood MR imaging at 7T allows detailed characterization of small perforating arteries such as lenticulostriate arteries. All techniques benefit from advances in parallel radiofrequency transmission technologies at ultrahigh field.

High-Degree Middle Cerebral Artery Stenosis : Can Advanced 3D DSA-MRI Fusion Imaging Better Illustrate Plaques and Perforators?

PURPOSE: Endovascular treatment in severe middle cerebral artery (MCA) stenosis is controversial owing to high rates of periprocedural complications, especially occlusion of the lenticulostriate arteries (LSA). The characteristics of LSAs and the spatial relationships between MCA plaques and LSAs using the fusion of three-dimensional (3D) digital subtraction angiography (DSA) and magnetic resonance imaging (3D DSA-MRI fusion) were investigated. METHODS: We retrospectively analyzed data from 32 ischemic stroke or transient ischemic attack patients with severe MCA stenosis, who underwent MRI and DSA within 2 weeks after symptom onset. The patients were divided into culprit and non-culprit MCA stenosis groups. The 3D DSA-MRI fusion was performed on dedicated workstations, which allowed automated overlays of the target vessels. The characteristics of LSAs, plaque distribution and lesion patterns, and their relationships were evaluated. RESULTS: The 3D DSA-MRI fusion image was able to illustrate the spatial relationships between MCA plaques and LSA orifices. Of 42 LSA stems in 32 patients, 10 had MCA plaque over the LSA orifice and were all found in the culprit MCA stenosis group. Over half (51.9%) of the LSA stems in patients with culprit MCA stenosis originated from the stenotic MCA segment. The MCA plaque-LSA orifice spatial relationships were classified into four types, which were significantly different between the two groups (p = 0.016). CONCLUSION: The 3D DSA-MRI fusion technique enables visualization of the LSA orifice and MCA plaque and their spatial relationships. This classification of the type of spatial relationships can provide insights into the pathogenesis of MCA stroke and useful guides for treatment strategies.

Cortical and Internal Watershed Infarcts Might Be Key Signs for Predicting Neurological Deterioration in Patients with Internal Carotid Artery Occlusion with Mild Symptoms.

BACKGROUND: Treatment for acute ischemic stroke due to large vessel occlusion (LVO) with mild symptoms is under discussion. Although most patients have good outcomes, some patients deteriorate and have unfavorable results. Imaging findings that predict the prognosis of LVO with mild symptoms are needed to identify patients who require treatment. In this study, we focused on watershed infarctions (WSIs), because this clinical phenomenon quite sensitively reflects changes in cerebral blood flow. The purpose of this study was to assess positive rates of WSI on MRI findings in patients with internal carotid artery (ICA) occlusion, and compare WSI-positive rates between patients divided according to their clinical course. METHODS: We retrospectively collected data of 1,531 patients who presented with acute ischemic stroke between June 2006 and July 2019. Among them, we chose symptomatic ICA occlusion patients with a past history of atrial fibrillation who were treated conservatively. We divided these patients into two groups, those with maintenance or improvement in their NIHSS score after hospitalization, and those whose NIHSS score worsened. We compared WSI-positive rates between these two groups. RESULTS: Thirty-seven of the 1,531 patients were included in this study. Of them, total NIHSS score was maintained or improved in 8 patients (group A), 3 of whom (37.5%) had internal watershed infarctions (IWIs). In group B, consisting of patients whose NIHSS score worsened by >2 at 7 days from symptom onset, 24 (82.8%) had IWIs. Group A thus had statistically lower IWI positivity rates than group B (p = 0.02). Three patients (37.5%) in group A had cortical watershed infarctions (CWIs), while 27 patients in group B (93.1%) had CWIs. Group A thus had a significantly lower CWI positivity rate than group B (p = 0.002). CONCLUSION: In patients with mildly symptomatic ICA occlusion, CWIs and IWIs might be key signs for predicting neurological deterioration after hospitalization.

Lenticulostriate Arteries and Basal Ganglia Changes in Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy, a High-Field MRI Study.

Background and Purpose: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) mainly affects the cerebral small arteries. We aimed to analyze changes in the lenticulostriate arteries (LSAs) and the basal ganglia in patients with CADASIL using high-field magnetic resonance imaging (7.0-T MRI). Methods: We examined 46 patients with CADASIL and 46 sex- and age-matched healthy individuals using 7.0-T MRI. The number and length of the LSAs, and the proportion of discontinuous LSAs were compared between the two groups. The Mini-Mental State Examination score, the modified Rankin Scale, the Barthel Index, and the MRI lesion load of the basal ganglia were also examined in patients with CADASIL. We analyzed the association between LSA measurements and the basal ganglia lesion load, as well as the association between LSA measurements and clinical phenotypes in this patient group. Results: We observed a decrease in the number of LSA branches (t = -2.591, P = 0.011), and an increase in the proportion of discontinuous LSAs (z = -1.991, P = 0.047) in patients with CADASIL when compared with healthy controls. However, there was no significant difference in the total length of LSAs between CADASIL patients and healthy individuals (t = -0.412, P = 0.682). There was a positive association between the number of LSA branches and the Mini-Mental State Examination scores of CADASIL patients after adjusting for age and educational level (ß = 0.438; 95% CI: 0.093, 0.782; P = 0.014). However, there was no association between LSA measurements and the basal ganglia lesion load among CADASIL patients. Conclusions: 7.0-T MRI provides a promising and non-invasive method for the study of small artery damage in CADASIL. The abnormalities of small arteries may be related to some clinical symptoms of CADASIL patients such as cognitive impairment. The lack of association between LSA measurements and the basal ganglia lesion load among the patients suggests that changes in the basal ganglia due to CADASIL are caused by mechanisms other than anatomic narrowing of the vessel lumen.

Correlation Between the Number of Lenticulostriate Arteries and Imaging of Cerebral Small Vessel Disease.

Background and purpose: Hypoperfusion plays an important role in the pathophysiology of cerebral small vessel disease (SVD). Lenticulostriate arteries (LSAs) are some of the most important cerebral arterial small vessels. This study aimed to investigate whether the number of LSAs was associated with the cerebral perfusion in SVD patients and determine the correlation between the number of LSAs and SVD severity. Methods: Five hundred and ninety-four consecutive patients who underwent digital subtraction angiography were enrolled in this study. The number of LSAs was determined. Computed tomography perfusion (CTP) was used to calculate the cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and time to peak (TTP). Magnetic resonance imaging (MRI) was performed to assess cerebral infarct, cerebral microbleeds (CMBs), white matter hyperintensities (WMHs), enlarged perivascular spaces (EPVSs), and lacunes. An SVD compound score was calculated to express the level of cerebral SVD load. Results: The SVD scores were negatively correlated with the number of the LSAs (P < 0.001, r s = -0.44). The number of LSAs was inversely associated with the presence of any type of SVD (P < 0.001). The adjusted ORs of the SVD severity were 0.31 for LSA group 1 (LSA > 20) vs. group 2 (LSA = 10-20) and 0.47 for LSA group 2 (LSA = 10-20) vs. group 3 (LSA < 10). MTT and TTP were significantly higher and CBF was significantly lower when the number of LSAs was between 5 and 10 on each side of the basal ganglia (P < 0.001, <0.001, and <0.001, respectively). The CBV was slightly lower when the number of LSAs was between 5 and 10, while it was significantly lower when the number was <5 on each side of the basal ganglia (P < 0.05, <0.0001, respectively). Conclusion: LSA count was lower in SVD patients than the non-SVD participants and there was a positive correlation between the cerebral perfusion and the number of LSAs. The LSA number was negatively associated with SVD severity, hypoperfusion might play an important role. This finding may have potentially important clinical implications for monitoring LSA in SVD patients.

The assessment of lenticulostriate arteries originating from middle cerebral artery using ultra high-field magnetic resonance time-of-flight angiography.

Time-of-flight angiography (ToF) was presented for the first time by Suryan and used by Hinshaw et al. This protocol allows to visualize blood flow within the vessels in vivo without the contrast administration, which is possible due to the large magnitude of magnetization, received from the moving spins and small magnitude of magnetization received from the stationary spins. Fourteen participants (male:female = 7:7) were analyzed, who have never been diagnosed with any central nervous system disease as well as any cardiovascular, metabolic disease and have never had any trauma. Although, the gold standard of cerebral vessel analysis is still DSA, ultra high-field 3D ToF-MRA shows clearer picture of all LSAs and the branches of LSAs in comparison to poor in contrast DSA imaging. Ultra high-field time-of-flight MRA is a valuable method in visualizing small perforating arteries, which can be used in the future as a diagnostic tool for clinical practice. The diversity of LSAs morphometry is vast and may alter during aging, thus the clinical anatomy of those vessels should be further investigated in vivo.