Association of brain arterial diameters with demographic and anatomical factors in a multi-national pooled analysis of cohort studies.

BACKGROUND AND PURPOSE: Brain arterial diameters are markers of cerebrovascular disease. Demographic and anatomical factors may influence arterial diameters. We hypothesize that age, sex, height, total cranial volume (TCV), and persistent fetal posterior cerebral artery (fPCA) correlate with brain arterial diameters across populations. METHODS: Participants had a time-of-flight MRA from nine international cohorts. Arterial diameters of the cavernous internal carotid arteries (ICA), middle cerebral arteries (MCA), and basilar artery (BA) were measured using LAVA software. Regression models assessed the association between exposures and brain arterial diameters. RESULTS: We included 6,518 participants (mean age: 70 ± 9 years; 41% men). Unilateral fPCA was present in 13.2% and bilateral in 3.2%. Larger ICA, MCA, and BA diameters correlated with older age (Weighted average [WA] per 10 years: 0.18 mm, 0.11 mm, and 0.12 mm), male sex (WA: 0.24 mm, 0.13 mm, and 0.21 mm), and TCV (WA: for one TCV standard deviation: 0.24 mm, 0.29 mm, and 0.18 mm). Unilateral and bilateral fPCAs showed a positive correlation with ICA diameters (WA: 0.39 mm and 0.73 mm) and negative correlation with BA diameters (WA: -0.88 mm and -1.73 mm). Regression models including age, sex, TCV, and fPCA explained on average 15%, 13%, and 25% of the ICA, MCA, and BA diameter interindividual variation, respectively. Using height instead of TCV as a surrogate of head size decreased the R-squared by 3% on average. CONCLUSION: Brain arterial diameters correlated with age, sex, TCV, and fPCA. These factors should be considered when defining abnormal diameter cutoffs across populations.

Variable Anatomy of the Middle Cerebral Artery from Its Origin to the Edge of the Sylvian Fissure: A Direct Fresh Brain Study.

The middle cerebral artery (MCA) is a major artery supplying blood to the brain and a common site of surgically treatable intracranial aneurysms. The MCA has anatomic variations that may have clinical significance. In order to investigate and document the extent of such variations, the MCA in 100 fresh brain hemispheres from 50 deceased patients, obtained from the Police Surgeon Office, Yangon General Hospital, Myanmar, was dissected and examined. Double MCA was observed in 2% of specimens. The termination patterns were bifurcation (72%), trifurcation (16%), and primary trunk (12%); early bifurcation was also observed (3%). The mean length of the main trunk (MT) was 20.6 ± 6.2 mm. The number of perforators ranged from 4 to 15 (mean = 9); most arose from the MT (96%), and the others originated at the bifurcation point (3%) and in postbifurcation divisions (1%). All of the perforators (100%) had a single branching pattern. The number of cortical branches ranged from 6 to 13 and included the orbitofrontal (98%), prefrontal (99%), precentral (95%), central (98%), temporopolar (87%), anterior temporal (89%), middle temporal (24%), posterior temporal (62%), temporo-occipital (69%), anterior parietal (88%), angular (83%), and posterior parietal (57%) arteries. Early cortical branches emerged from the MT in 52% of specimens. These data can help anatomists, radiologists, and neurosurgeons in preoperative assessment, surgical planning, and selection of surgical approach.

The contribution of the middle cerebral artery and callosal artery to the vascularisation of the Facies convexa of the brain in horses with reference to the equine-specific cartographic pattern of the neopallium.

BACKGROUND: The extremely complex surface architecture of the equine brain does not allow a uniform transfer of anatomical data from other mammalian species, e.g., dog or cat. Rather, a special approach is required to elucidate the equine-specific patterns of cerebral vascular ramifications. Therefore, a novel cartographic system was applied. Prior attention was paid to the A. cerebri media (MCA) and to the A. corporis callosi (CA), as they spread over the widest part of the neopallium's Facies convexa (i.e. the lateral and dorsal surface), thus being of particular interest in terms of surgical treatment of trauma of the skull and brain. MATERIALS AND METHODS: The brains of 17 adult warmblood horses were studied. The neopallium's Facies convexa was subdivided into 15 sectors clearly delineated by the primary sulci and by related auxiliary lines. The courses and destinations of main branches (= branches of 1st or 2nd order, with a minimum calibre of 0.75 mm) of MCA and CA were topographically analysed by means of superimposed graphical sketches. RESULTS: The MCA had six main branches (numbered in rostrocaudal direction); the CA had seven main branches. The main branches of the MCA spread over the widest part of the Facies convexa, but never reached the rostral pole and the caudal pole of the neopallium. Clearly, the main branches of CA proceeded from the hemisphere's medial side across the Margo dorsalis cerebri, thus supplying rostrodorsal and dorsal sectors of the Facies convexa. CONCLUSIONS: The topographical analysis of the vascular ramification patterns (regions of residence) in combination with the cartographic system of sectors of the neopallium respected the equine-specific surface architecture. It highlighted the distinct vascular supply areas and the particular multiple-supply situations especially in sectors presumably related to the equine area motorica.

Impact of early division of the middle cerebral artery on outcome following mechanical thrombectomy.

BACKGROUND: Mechanical thrombectomy has become the standard care for acute ischemic stroke caused by large vessel occlusion. However, complete reperfusion cannot be achieved in all cases, and several factors influencing the results of mechanical thrombectomy have been investigated. Among others, a tortuous anatomy is associated with lower rates of complete reperfusion. We aimed to investigate whether an early division of the middle cerebral artery has an impact on reperfusion results in mechanical thrombectomy. METHODS: Retrospective review of consecutive patients with M1 occlusion treated endovascularly between January 2016 and December 2019 at three tertiary care centers. The study group was dichotomized based on the length of the M1 segment. Early division of the middle cerebral artery was defined as a maximum length of 10 mm of the M1 segment. Primary endpoints were first-pass mTICI scores of 3, ≥2c, and ≥2b. Secondary endpoints contained final reperfusion, number of device-passes, time interval from groin puncture to reperfusion, rate of postinterventional symptomatic intracranial hemorrhage, and frequency of emboli of new territory. RESULTS: Among 284 included patients, 70 presented with an early division of the M1 segment (25%). Reperfusion results did not differ significantly between early and late division of M1. A higher rate of symptomatic intracranial hemorrhage was found in the group with an early M1 division treated with aspiration only (14.3% vs. 0%; p = 0.013). Patients with late M1 division had a significantly higher rate of large artery sclerosis (19.2% vs. 8.6%, p = 0.039). CONCLUSION: The anatomic variant of an early division of the middle cerebral artery was not a predictor for incomplete reperfusion.

Morphological and Hemodynamic Risk Factors for Middle Cerebral Artery Aneurysm: a Case-Control Study of 190 Patients.

This study analyzed morphometric and hemodynamic parameters of aneurysmal and non-aneurysmal middle cerebral artery (MCA) bifurcations and their relationship with optimal values derived from the principle of minimum work (PMW). The study included 96 patients with MCA aneurysm and 94 controls. Aneurysm patients presented with significantly higher values of the radius and cross-sectional area of the MCA trunk, angle between the post-bifurcation branches (α angle) and volume flow rate (VFR) and had significantly lower values of junction exponent and pulsatility index than the controls. The Φ1 and Φ2 angles (angles between the MCA trunk axis and the larger and smaller branch, respectively) and α angle in all groups were significantly larger than the optimal PMW-derived angles. The most important independent predictors of MCA aneurysm were junction exponent (odds ratio, OR = 0.42), α angle (OR = 1.07) and VFR (OR = 2.36). Development of cerebral aneurysms might be an independent effect of abnormalities in hemodynamic and morphometric factors. The risk of aneurysm increased proportionally to the deviation of morphometric parameters of the bifurcation from their optimal PMW-derived values. The role of bifurcation angle in aneurysm development needs to be explained in future research as the values of this parameter in both aneurysm patients and non-aneurysmal controls in were scattered considerably around the PMW-derived optimum.

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.

Vascular Morphology has No Direct Relationship with Atherosclerotic Plaque Burden in Patients with Symptomatic Middle Cerebral Artery Stenosis.

BACKGROUND: The vascular morphology and the characteristics of atherosclerotic plaques in the middle cerebral artery (MCA) have not been fully studied with high-resolution magnetic resonance imaging (HR-MRI). OBJECTIVE: HR-MRI was applied to investigate vascular morphology and atherosclerotic plaque in patients with symptomatic MCA stenosis. MATERIALS AND METHODS: A total of 343 patients with symptomatic MCA stenosis were enrolled in this study. All the patients were examined by HR-MRI to analyze the morphology of MCA and the M1 segment (MCA-M1), the characteristics and the location of the plaques. RESULTS: The proportion of L-shaped MCA-M1 decreased, while the proportion of S-shaped MCAM1 increased with age. The anterior plaques were the most common in all the patients. The superior plaques were relatively common in patients with L-shaped and U-shaped MCA-M1, while the inferior plaques were relatively common in patients with inverted U-shaped and S-shaped MCAM1. Among all the plaques, the majority were isointense or heterogeneous. The MCA-M1 morphology had no direct relationship with the common risk factors of atherosclerosis and the clinical outcomes of the patients after 12 months of follow up. CONCLUSION: The morphology of MCA-M1 is not directly related to the plaque burden or the degree of stenosis in patients with symptomatic MCA stenosis. The morphology of MCA-M1 is not associated with the risk factors of atherosclerosis, or the clinical outcomes of the patients.

Propofol/Remifentanil Anesthesia Might Not Alter the Middle Cerebral Artery Diameter by Digital Subtraction Angiography.

INTRODUCTION: Transcranial Doppler (TCD) of the middle cerebral artery (MCA) enables the measurement of the mean blood velocity (MCAVm) and the estimation of the cerebral blood flow (CBF), provided that no significant changes occur in the MCA diameter (MCADiam). Previous studies described a decrease in the MCAVm associated with the induction of total intravenous anesthesia (TIVA) by propofol and remifentanil. This decrease in blood velocity might be interpreted as a decrease in the CBF only where the MCADiam is not modified across TCD examinations. METHODS: In this observational study, we measured the MCADiam of 24 subjects (almost exclusively females) on digital subtraction angiography under awake and TIVA conditions. RESULTS: Across the two phases, we observed a decrease in the mean arterial blood pressure (from 84 ± 9 to 71 ± 6 mmHg; p < 0.001) and heart rate (76 ± 10 vs. 65 ± 8 beats/min; p < 0.001), and a concomitant decrease in the MCAVm (61 vs. 42 cm/s; p < 0.001). In contrast, the MCADiam did not vary in association with TIVA (2.3 ± 0.2 vs. 2.3 ± 0.2 mm; p = 0.52). CONCLUSIONS: Those results suggested that in this population, no significant changes in the MCADiam are associated with TIVA.

The Artery of Aphasia, A Uniquely Sensitive Posterior Temporal Middle Cerebral Artery Branch that Supplies Language Areas in the Brain: Anatomy and Report of Four Cases.

BACKGROUND: Arterial disruption during brain surgery can cause devastating injuries to wide expanses of white and gray matter beyond the tumor resection cavity. Such damage may occur as a result of disrupting blood flow through en passage arteries. Identification of these arteries is critical to prevent unforeseen neurologic sequelae during brain tumor resection. In this study, we discuss one such artery, termed the artery of aphasia (AoA), which when disrupted can lead to receptive and expressive language deficits. METHODS: We performed a retrospective review of all patients undergoing an awake craniotomy for resection of a glioma by the senior author from 2012 to 2018. Patients were included if they experienced language deficits secondary to postoperative infarction in the left posterior temporal lobe in the distribution of the AoA. The gross anatomy of the AoA was then compared with activation likelihood estimations of the auditory and semantic language networks using coordinate-based meta-analytic techniques. RESULTS: We identified 4 patients with left-sided posterior temporal artery infarctions in the distribution of the AoA on diffusion-weighted magnetic resonance imaging. All 4 patients developed substantial expressive and receptive language deficits after surgery. Functional language improvement occurred in only 2/4 patients. Activation likelihood estimations localized parts of the auditory and semantic language networks in the distribution of the AoA. CONCLUSIONS: The AoA is prone to blood flow disruption despite benign manipulation. Patients seem to have limited capacity for speech recovery after intraoperative ischemia in the distribution of this artery, which supplies parts of the auditory and semantic language networks.

Defining the lateral limits of the endoscopic endonasal transtuberculum transplanum approach: anatomical study with pertinent quantitative analysis.

OBJECTIVE: The extended endoscopic endonasal transtuberculum transplanum approach is currently used for the surgical treatment of selected midline anterior skull base lesions. Nevertheless, the possibility of accessing the lateral aspects of the planum sphenoidale could represent a limitation for such an approach. To the authors' knowledge, a clear definition of the eventual anatomical boundaries has not been delineated. Hence, the present study aimed to detail and quantify the maximum amount of bone removal over the planum sphenoidale required via the endonasal pathway to achieve the most lateral extension of such a corridor and to evaluate the relative surgical freedom. METHODS: Six human cadaveric heads were dissected at the Laboratory of Surgical NeuroAnatomy of the University of Barcelona. The laboratory rehearsals were run as follows: 1) preliminary predissection CT scans, 2) the endoscopic endonasal transtuberculum transplanum approach (lateral limit: medial optocarotid recess) followed by postdissection CT scans, 3) maximum lateral extension of the transtuberculum transplanum approach followed by postdissection CT scans, and 4) bone removal and surgical freedom analysis (a nonpaired Student t-test). A conventional subfrontal bilateral approach was used to evaluate, from above, the bone removal from the planum sphenoidale and the lateral limit of the endonasal route. RESULTS: The endoscopic endonasal transtuberculum transplanum approach was extended at its maximum lateral aspect in the lateral portion of the anterior skull base, removing the bone above the optic prominence, that is, the medial portion of the lesser sphenoid wing, including the anterior clinoid process. As expected, a greater bone removal volume was obtained compared with the approach when bone removal is limited to the medial optocarotid recess (average 533.45 vs 296.07 mm2; p < 0.01). The anteroposterior diameter was an average of 8.1 vs 15.78 mm, and the laterolateral diameter was an average of 18.77 vs 44.54 mm (p < 0.01). The neurovascular contents of this area were exposed up to the insular segment of the middle cerebral artery. The surgical freedom analysis revealed a possible increased lateral maneuverability of instruments inserted in the contralateral nostril compared with a midline target (average 384.11 vs 235.31 mm2; p < 0.05). CONCLUSIONS: Bone removal from the medial aspect of the lesser sphenoid wing, including the anterior clinoid process, may increase the exposure and surgical freedom of the extended endoscopic endonasal transtuberculum transplanum approach over the lateral segment of the anterior skull base. Although this study represents a preliminary anatomical investigation, it could be useful to refine the indications and limitations of the endoscopic endonasal corridor for the surgical management of skull base lesions involving the lateral portion of the planum sphenoidale.

Supraorbital vs Endo-Orbital Routes to the Lateral Skull Base: A Quantitative and Qualitative Anatomic Study.

BACKGROUND: Various extensions of the supraorbital approach reach the lateral and parasellar middle cranial fossa regions by removing the orbital rim and greater/lesser sphenoid wings. Recent proposals of a purely endoscopic ventral transorbital pathway to these regions heighten the need to compare these surgical windows. OBJECTIVE: To detail the lateral and parasellar middle cranial fossa regions and quantify exposures by 2 surgical windows (transcranial and transorbital) through anatomic study. METHODS: In 5 cadaveric specimens (10 sides), dissections consisted of 3 stages: stage 1 began with the supraorbital approach via the eyebrow; stage 2, endo-orbital approach via the superior eyelid, continued with removal of lesser and greater sphenoid wings; and stage 3, extended supraorbital, re-evaluated the gains of stage 2 from the perspective of stage 1. Operative working areas were quantified in Sylvian, anterolateral temporal, and parasellar regions; bone removal volumes were measured at each stage (nonpaired Student t-test). RESULTS: Visualization into the anterolateral temporal and Sylvian areas, though varied in perspective, were comparable with either eyelid or transcranial routes. Compared with transcranial views through a supraorbital window, the eyelid approach significantly increased exposure in the parasellar region with wider angle of attack (P < .01) and achieved comparable bone removal volumes. CONCLUSION: Stage 2's unique anatomic view of the lateral and parasellar middle cranial fossa regions paves the way for possible surgical application to select pathologies typically treated via transcranial approaches. Disadvantages may be the surgeon's unfamiliarity with the anatomy of this purely endoscopic, ventral route and difficulties of dural and orbital repair.

Quantitative Analysis of Geometry and Lateral Symmetry of Proximal Middle Cerebral Artery.

BACKGROUND: The purpose of our work is to quantitatively assess clinically relevant geometric properties of proximal middle cerebral arteries (pMCA), to investigate the degree of their lateral symmetry, and to evaluate whether the pMCA can be modeled by using state-of-the-art deformable image registration of the ipsi- and contralateral hemispheres. METHODS: Individual pMCA segments were identified, quantified, and statistically evaluated on a set of 55 publicly available magnetic resonance angiography time-of-flight images. Rigid and deformable image registrations were used for geometric alignment of the ipsi- and contralateral hemispheres. Lateral symmetry of relevant geometric properties was evaluated before and after the image registration. RESULTS: No significant lateral differences regarding tortuosity and diameters of contralateral M1 segments of pMCA were identified. Regarding the length of M1 segment, 44% of all subjects could be considered laterally symmetrical. Dominant M2 segment was identified in 30% of men and 9% of women in both brain hemispheres. Deformable image registration performed significantly better (P < .01) than rigid registration with regard to distances between the ipsi- and the contralateral centerlines of M1 segments (1.5 ± 1.1 mm versus 2.8 ± 1.2 mm respectively) and between the M1 and the anterior cerebral artery (ACA) branching points (1.6 ± 1.4 mm after deformable registration). CONCLUSIONS: Although natural lateral variation of the length of M1 may not allow for sufficient modeling of the complete pMCA, deformable image registration of the contralateral brain hemisphere to the ipsilateral hemisphere is feasible for localization of ACA-M1 branching point and for modeling 71 ± 23% of M1 segment.

Assessment of the Temporopolar Artery as a Donor Artery for Intracranial-Intracranial Bypass to the Middle Cerebral Artery: Anatomic Feasibility Study.

BACKGROUND: Intracranial-intracranial bypass is a valuable cerebral revascularization option. Despite several advantages, one of the main shortcomings of the intracranial-intracranial bypass is the possibility of ischemic complications of the donor artery. However, when sacrificed, the temporopolar artery (TPA) is not associated with major neurologic deficits. We sought to define the role of TPA as a donor for revascularization of the middle cerebral artery (MCA). METHODS: Pterional craniotomy was performed on 14 specimens. The TPA was released from arachnoid trabecula, and the small twigs to the temporal lobe were cut. The feasibility of side-to-side and end-to-side bypass to the farthest arterial targets on insular, opercular, and cortical MCA branches was assessed. The distance of the bypass point was measured in reference to limen insulae. RESULTS: A total of 15 TPAs were assessed (1 specimen had 2 TPAs). The average cisternal length of the TPA was 37.3 mm. For side-to-side bypass, the TPA was a poor candidate as an intracranial donor, except for the cortical orbitofrontal artery, which was reached in 87% of cases. However, the end-to-side bypass was successfully completed for most arteries (87%-100%) on the anterior frontal operculum and more than 50% of the cortical or opercular middle and posterior temporal arteries. There was no correlation between the TPA's cisternal length and maximum bypass reach. CONCLUSIONS: When of favorable diameter, the TPA is a competent donor for intracranial-intracranial bypass to MCA branches at the anterior insula, and anterior frontal and middle temporal opercula (arteries anterior to the precentral gyrus coronal plane).

Maxillary Artery to Middle Cerebral Artery Bypass: A Novel Technique for Exposure of the Maxillary Artery.

OBJECTIVE: To define the maxillary artery (MaxA) anatomy and present a novel technique for exposing and preparing this vessel as a bypass donor. METHODS: Cadaveric and radiologic studies were used to define the MaxA anatomy and show a novel method for harvesting and preparing it for extracranial to intracranial bypass. RESULTS: The MaxA runs parallel to the frontal branch of the superficial temporal artery and is located on average 24.8 ± 3.8 mm inferior to the midpoint of the zygomatic arch. The pterygoid segment of the MaxA is most appropriate for bypass with a maximal diameter of 2.5 ± 0.4 mm. The pterygoid segment can be divided into a main trunk and terminal part based on anatomic features and use in the bypass procedure. The main trunk of the pterygoid segment can be reached extracranially, either by following the deep temporal arteries downward toward their origin from the MaxA or by following the sphenoid groove downward to the terminal part of the pterygoid segment, which can be followed proximally to expose the entire MaxA. In comparison, the prebifurcation diameter of the superficial temporal artery is 1.9 ± 0.5 mm. The average lengths of the mandibular and pterygoid MaxA segments are 6.3 ± 2.4 and 6.7 ± 3.3 mm, respectively. CONCLUSIONS: The MaxA can be exposed without zygomatic osteotomies or resection of the middle fossa floor. Anatomic landmarks for exposing the MaxA include the anterior and posterior deep temporal arteries and the pterygomaxillary fissure.

Middle cerebral artery diameter changes during rhythmic handgrip exercise in humans.

Transcranial Doppler (TCD) sonography is a frequently employed technique for quantifying cerebral blood flow by assuming a constant arterial diameter. Given that exercise increases arterial pressure by sympathetic activation, we hypothesized that exercise might induce a change in the diameter of large cerebral arteries. Middle cerebral artery (MCA) cross-sectional area was assessed in response to handgrip exercise by direct magnetic resonance imaging (MRI) observations. Twenty healthy subjects (11 female) performed three 5 min bouts of rhythmic handgrip exercise at 60% maximum voluntary contraction, alternated with 5 min of rest. High-resolution 7 T MRI scans were acquired perpendicular to the MCA. Two blinded observers manually determined the MCA cross-sectional area. Sufficient image quality was obtained in 101 MCA-scans of 19 subjects (age-range 20-59 years). Mixed effects modelling showed that the MCA cross-sectional area decreased by 2.1 ± 0.8% (p = 0.01) during handgrip, while the heart rate increased by 11 ± 2% (p < 0.001) at constant end-tidal CO2 (p = 0.10). In conclusion, the present study showed a 2% decrease in MCA cross-sectional area during rhythmic handgrip exercise. This further strengthens the current concept of sympathetic control of large cerebral arteries, showing in vivo vasoconstriction during exercise-induced sympathetic activation. Moreover, care must be taken when interpreting TCD exercise studies as diameter constancy cannot be assumed.

Anatomy of the Middle Cerebral Artery: Cortical Branches, Branching Pattern and Anomalies.

The middle cerebral artery (MCA) covers a large part of the cerebral hemispheres and is therefore exposed during surgical intervention in this area. Aspects of cerebral branches tend to vary, different branching patterns can be described, and several anomalies can be observed. Knowledge of these variations and anomalies is important and can be helpful to neurosurgeons and clinicians. The aim of this manuscript was to review the available literature on the cortical branches, branching pattern and anomalies of the MCA, to identify the gaps in the literature, and to fill these gaps by including the results of a pilot study. Twenty hemispheres were perfused with colored silicone and the MCA was dissected. For the cortical branches, the diameter, length, presence, duplication and origins were noted. Most commonly duplicated was the anterior parietal artery in 30.0%, and most commonly absent was the common temporal artery in 65.0%. A detailed description on the origins is given. Criteria were described for the bifurcation subtypes and medial bifurcation (50.0%) was most commonly observed. No anomalies were observed. Aspects previously neglected of the MCA cortical branches were reported in the pilot study. The branching subtypes were identified and criteria are given. Illustrations of the different branching subtypes and anomalies are provided. Certain aspects of the MCA anatomy have been neglected, and future studies should give adequate descriptions of the MCA cortical branches, MCA branching pattern, and any anomalies observed.

Cortical branches of the middle cerebral artery in silver fox (Vulpes vulpes)

The study of the vascularization of the cerebrum in silver fox was performed on 80 cerebral hemispheres. It was found that the middle cerebral artery is the strongest vessel supplying blood to the cerebrum. The artery gets divided into ten permanent branches. Two olfactory arteries supply the region of the cerebrum located on the border between the old and the new cortex. The other eight supply the region of the new cortex. The frontal, parietal and temporal branches descended independently from the main trunk of the middle cerebral artery or formed a common trunk. Common trunks for respective groups of branches have been described as the anterior, superior and posterior middle cerebral artery. The alterior olfactory artery in 5% of cases and posterior olfactory artery in 2.5% of cases were independent branches of the middle cerebral artery extending from the rostral cerebral artery.(AU)

The Microsurgical Anatomy of the Orbitofrontal Arteries.

OBJECTIVE: The orbitofrontal (or frontobasal) arteries (OFAs) are the medial (MOFA) and lateral (LOFA) orbitofrontal artery, branches of the anterior and middle cerebral artery, respectively. They supply the orbitofrontal cortex. The purpose of this microscopic cadaveric study was the detailed and precise anatomic identification of the OFAs along their course. METHODS: Twenty formalin-fixed, colored latex-injected cadaveric heads were studied with the aid of an operating microscope and microsurgical instrumentation. The anatomy of the OFAs was examined after removing the cerebrum from the cranial vault. Anatomic features of the MOFA and LOFA were investigated and assessed in relation to demographic and anthropometric variables. RESULTS: The MOFA supplies approximately 15 branches and LOFA almost 16 branches. The MOFA provides 1 branch to the olfactory bulb and 4 branches to the olfactory tract, and there are approximately 2 MOFA-LOFA anastomoses per hemisphere (novel finding). The MOFA origin is located approximately 7.9 mm anterior to the anterior communicating artery and 4.7 cm posterior to the anterior limit of the gyrus rectus. The LOFA origin is located approximately 11.1 mm from the middle cerebral artery bifurcation. Younger, shorter, and lighter individuals have more MOFA-LOFA anastomoses. Finally, the number of MOFA branches for the olfactory bulb is positively correlated with the number of MOFA branches for the olfactory tract, as well as with the number of MOFA-LOFA anastomoses. CONCLUSIONS: The present study provides a detailed description of the OFAs' microsurgical anatomy and can help neurosurgeons to easily identify, manipulate, and preserve these vessels during surgery.

Angiographic Morphometry of Internal Carotid Artery Circulation in Turkish Children.

AIM: Knowledge of cerebrovascular morphology is integral in planning neuroendovascular interventions, especially for procedures involving placement of stents, flow diverters or stentrievers. There is insufficient data on angiographic normative values of cerebral circulation in the pediatric age group since angiograms are uncommonly performed in children except for arteriovenous malformations in which arterial dimensions are larger than normal. We aimed to measure the diameters of internal carotid circulation (ICC) arteries on digital subtraction angiograms of pediatric patients and determine the growth trends. MATERIAL AND METHODS: This is a retrospective cross-sectional study measurements of ICC arteries of 64 pediatric patients (4-122 months) with retinoblastoma undergoing intra-arterial chemotherapy. RESULTS: Petrous, cavernous, supraclinoid and choroidal segments of internal carotid artery (ICA) and anterior cerebral artery (ACA) diameters had significant correlation with age. Most of the growth was noted in the first 36-48 months of life. Middle cerebral artery (MCA) diameter did not show significant correlation with age. 87% of the adult diameter of the MCA was attained in the first 6 months of life. ICC arteries reached 81% to 99% of adult sizes in the first 48 months of life. On the contrary, the main iliac artery was only 59% of the adult diameter at this age group. CONCLUSION: Use of current intracranial stents in children appears tolerable due to the growth pattern of ICC arteries. Based on this data, the current armamentarium of intracranial stents or stent-like devices is sufficient to cover the need in the pediatric population.

Unfused or twig-like middle cerebral artery.

INTRODUCTION: The knowledge of anatomic variations of the cerebral arterial circulation may be important to decide on the safest surgical or endovascular treatment method. Variations in the middle cerebral artery (MCA) territory seems to be less frequent than the other intracranial arteries. During the embryonic stage the primitive MCA is hypothesized to be made up of arterial twigs and these twigs will generate the definitive MCA at the end of the development stage. As in our cases, an early interruption in this period will prevent the evolution of MCA normally and a plexiform arterial network will create the M1 segment of MCA which is the so-called extremely rare unfused or twig-like (Uf/Tw) MCA variation. Our aim is to define and evaluate the angiographical features of Uf/Tw MCA. METHODS: The diagnosis of Uf/Tw MCA was evaluated in a total of 4855 diagnostic cerebral catheter angiograms, retrospectively. The coexisting intracranial pathologies were also interpreted with former radiological examinations. A review of the literature is provided. RESULTS: A total of six cases of Uf/Tw MCA was identified on angiograms accompanying ipsilateral internal carotid artery (ICA) occlusion and contralateral ICA supraclinoid segment aneurysm in one case, and cingulate gyrus AVM in the other. In two different cases, CT or MRI examinations revealed coexisting subarachnoid hemorrhage and misdiagnosis of forniceal AVM in one case, and temporal arachnoid cyst and parenchymal hematoma in the other. CONCLUSION: Lack of data and knowledge about the Uf/Tw MCA variation may cause misdiagnosis and unnecessary treatment attempts.