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Branching patterns of microvascular networks influence vascular resistance and allow control of peripheral flow distribution. The aim of this paper was to analyze these branching patterns in human cerebral cortex. Digital three-dimensional images of the microvascular network were obtained from thick sections of India ink-injected human brain by confocal laser microscopy covering a large zone of secondary cortex. A novel segmentation method was used to extract the skeletons of 228 vascular trees (152 arterioles and 76 venules) and measure the diameter at every vertex. The branching patterns (area ratios and angles of bifurcations) of nearly 10,000 bifurcations of cortical vascular trees were analyzed, establishing their statistical properties and structural variations as a function of the vessel nature (arterioles versus venules), the parent vessel topological order or the bifurcation type. We also describe their connectivity and discuss the relevance of the assumed optimal design of vascular branching to account for the complex nature of microvascular architecture. The functional implications of some of these structural variations are considered. The branching patterns established from a large database of a human organ contributes to a better understanding of the bifurcation design and provides an essential reference both for diagnosis and for a future large reconstruction of cerebral microvascular network.

The pathologic validation of European Alzheimer's Disease Consortium Alzheimer's Disease Neuroimaging Initiative Center Harmonized Hippocampal Segmentation Protocol (HarP).Temporal lobes of nine Alzheimer's disease (AD) and seven cognitively normal subjects were scanned post-mortem at 7 Tesla. Hippocampal volumes were obtained with HarP. Six-micrometer-thick hippocampal slices were stained for amyloid beta (Aβ), tau, and cresyl violet. Hippocampal subfields were manually traced. Neuronal counts, Aβ, and tau burden for each hippocampal subfield were obtained.We found significant correlations between hippocampal volume and Braak and Braak staging (ρ = -0.75, P = .001), tau (ρ = -0.53, P = .034), Aβ burden (ρ = -0.61, P = .012), and neuronal count (ρ = 0.77, P.001). Exploratory subfield-wise significant associations were found for Aβ in Cornu Ammonis (CA)1 (ρ = -0.58, P = .019) and subiculum (ρ = -0.75, P = .001), tau in CA2 (ρ = -0.59, P = .016), and CA3 (ρ = -0.5, P = .047), and neuronal count in CA1 (ρ = 0.55, P = .028), CA3 (ρ = 0.65, P = .006), and CA4 (ρ = 0.76, P = .001).The observed associations provide pathological confirmation of hippocampal morphometry as a valid biomarker for AD and pathologic validation of HarP.

After a short overview of the history of our knowledge of the pineal gland, its anatomy and its function, this work is primarily devoted to the relationships of the pineal gland to the nerve structures which delineate the pineal region. The complex surrounding blood vessels located in the quadrigeminal cistern are described with a special focus on the numerous venous trunks. Finally, the pineal blood supply is studied in three steps: (1) The arterial supply obtained through several groups of pineal arteries stemming mainly from the medial posterior choroidal arteries; (2) The venous drainage by the lateral pineal veins flowing, in most cases, into the cerebral vein of Galen; (3) The intrapineal vascular architecture with specific features concerning the central part of the gland highly vascularized by large sinusoid capillaries and its peripheral part poorly vascularized by small and fine blood vessels.

The development of neuroimaging has allowed clinicians to improve clinicoanatomic correlations in patients with stroke. Anatomic structures are well delineated on MRI, but there is a lack of standardization in their arterial supply. As in our previous study depicting the arterial supply of the brainstem and cerebellum, we present a system of 12 axial sections of the hemispheres depicting the dominant arterial territories, the most important anatomic structures, and Brodmann's areas. The area of variation of the cortical territory of the anterior, middle, and posterior cerebral arteries is also represented. These sections may be used as a practical tool to determine arterial territories on CT or MRI, and may help establish consistent clinicoanatomic correlations in patients with supratentorial stroke.

BackgroundThis study aimed to have international experts converge on a harmonized definition of whole hippocampus boundaries and segmentation procedures, to define standard operating procedures for magnetic resonance (MR)-based manual hippocampal segmentation.MethodsThe panel received a questionnaire regarding whole hippocampus boundaries and segmentation procedures. Quantitative information was supplied to allow evidence-based answers. A recursive and anonymous Delphi procedure was used to achieve convergence. Significance of agreement among panelists was assessed by exact probability on Fisher's and binomial tests.ResultsAgreement was significant on the inclusion of alveus/fimbria (P = .021), whole hippocampal tail (P = .013), medial border of the body according to visible morphology (P = .0006), and on this combined set of features (P = .001). This definition captures 100% of hippocampal tissue, 100% of Alzheimer’s disease-related atrophy, and demonstrated good reliability on preliminary intrarater (0.98) and inter-rater (0.94) estimates.DiscussionConsensus was achieved among international experts with respect to hippocampal segmentation using MR resulting in a harmonized segmentation protocol. published

Studies on human brain microcirculation have thus far yielded few quantitative data, preventing the closest possible interpretation of functional imaging methods such as fMRI and PET that necessarily rely on robustly delineated morphology of haemodynamic systems. Inadequate data in this area can lead to severe underestimation of the spatial specificity of the BOLD response. We took thick sections of Indian ink injected human brain and, using confocal laser microscopy and a novel three-dimensional computer-assisted method we extracted and analyzed hundreds of thousands of vascular segments within a large area of cortex. From this database the global densities, the statistical distributions of diameters and lengths were analysed, separating the tree-like and the net-like parts of the microcirculation. Furthermore, our analysis included variations in volume density along the cortical depth and along vectors parallel to the cortical surface. These morphometric parameters are all key requirements for a sound model of cerebral microcirculation.

Introduction The advent of neuroimaging has allowed clinicians to improve clinico-anatomic correlations in patients with strokes. Anatomic structures are now well delineated on magnetic resonance imaging, and a knowledge of arterial territories is needed to achieve accurate localization of ischemic lesions. MRI studies have re-evaluated the clinical spectrum of both anterior and posterior circulation strokes. Because the topographic, etiologic, and clinical spectra vary, large prospective studies including well-documented patients are of upmost importance. Classical syndromes have been revisited and new clinical patterns highlighted. However, most of the recent studies are based on various anatomic support and sometimes even lack anatomic reference. In this latter case, MRI is sometimes even considered to be an effective means of identifying etiologies according to the location of the infarction. On the other hand, only scarce reports exist in which the arterial vascular territories are well identified by anatomic studies. This lack of standardization in both arterial territory localization and the planes used to identify them, mar totally the accuracy of such reports. This recent neuroimaging development necessitates a precise and standardized tool for anatomo-radioclinical correlations. However, a perfect knowledge in the general organization of brain arterial circulation is the first step needed for a good understanding in some particularities of brain arterial territories. The present chapter is designed to show precise brain arterial circulation organization and to depict brain arterial territories in a form directly applicable to neuroimaging slices in clinical practice. General organization of brain arterial circulation Brainstem Arterial trunks supplying the brainstem include: vertebral artery, basilar artery, anterior and posterior spinal arteries, posterior inferior cerebellar artery, anterior inferior cerebellar artery, superior cerebellar artery, posterior cerebral artery, and anterior choroidal artery (Fig. 29.1).

The development of neuroimaging has allowed clinicians to improve clinicoanatomic correlations in patients with strokes.Brainstem and cerebellum structures are well delineated on MRI, but there is a lack of standardization in their arterial supply. We present a system of 12 brainstem and cerebellum axial sections, depicting the dominant arterial territories and the most important anatomic structures. These sections may be used as a practical tool to determine arterial territories on MRI, and may help establish consistent clinicoanatomic correlations in patients with brainstem and cerebellar ischemic strokes.NEUROLOGY 1996;47: 1125-1135

La technique d'injection a l'encre de Chine suivie de coupes ou d'eclaircissement a permis de presenter une etude topographique precise des centres du tronc cerebral (Duvernoy, 1978); elle est actuellement appliquee aux vaisseaux des hemispheres cerebraux et du diencephale. Cette technique permet egalement d'evaluer la circulation sanguine d'une region ou d'un noyau et d'en etablir avec precision les territoires vasculaires arteriels et veineux. Le but de ce travail est de montrer que, par une technique d'injection intravasculaire, il est possible d'evaluer avec precision la topographie des centres nerveux encephaliques et d'en etudier l'architecture vasculaire fonctionnelle.