Visualization-Based Mapping of Language Function in the Brain

Cortical language maps, obtained through intraoperative electrical stimulation studies, provide a rich source of information for research on language organization. Previous studies have shown interesting correlations between the distribution of essential language sites and such behavioral indicators as verbal IQ and have provided suggestive evidence for regarding human language cortex as an organization of multiple distributed systems. Noninvasive studies using ECoG, PET, and functional MR lend support to this model; however, there as yet are no studies that integrate these two forms of information. In this paper we describe a method for mapping the stimulation data onto a 3-D MRI-based neuroanatomic model of the individual patient. The mapping is done by comparing an intraoperative photograph of the exposed cortical surface with a computer-based MR visualization of the surface, interactively indicating corresponding stimulation sites, and recording 3-D MR machine coordinates of the indicated sites. Repeatability studies were performed to validate the accuracy of the mapping technique. Six observers—a neurosurgeon, a radiologist, and four computer scientists, independently mapped 218 stimulation sites from 12 patients. The mean distance of a mapping from the mean location of each site was 2.07 mm, with a standard deviation of 1.5 mm, or within 5.07 mm with 95% confidence. Since the surgical sites are accurate within approximately 1 cm, these results show that the visualization-based approach is accurate within the limits of the stimulation maps. When incorporated within the kind of information system envisioned by the Human Brain Project, this anatomically based method will not only provide a key link between noninvasive and invasive approaches to understanding language organization, but will also provide the basis for studying the relationship between language function and anatomical variability

Computerized Analysis of Magnetic Resonance Images to Study Cerebral Anatomy in Developing Neonates

The study of cerebral anatomy in developing neonates is of great importance for the understanding of brain development during the early period of life. This dissertation therefore focuses on three challenges in the modelling of cerebral anatomy in neonates during brain development. The methods that have been developed all use Magnetic Resonance Images (MRI) as source data. To facilitate study of vascular development in the neonatal period, a set of image analysis algorithms are developed to automatically extract and model cerebral vessel trees. The whole process consists of cerebral vessel tracking from automatically placed seed points, vessel tree generation, and vasculature registration and matching. These algorithms have been tested on clinical Time-of- Flight (TOF) MR angiographic datasets. To facilitate study of the neonatal cortex a complete cerebral cortex segmentation and reconstruction pipeline has been developed. Segmentation of the neonatal cortex is not effectively done by existing algorithms designed for the adult brain because the contrast between grey and white matter is reversed. This causes pixels containing tissue mixtures to be incorrectly labelled by conventional methods. The neonatal cortical segmentation method that has been developed is based on a novel expectation-maximization (EM) method with explicit correction for mislabelled partial volume voxels. Based on the resulting cortical segmentation, an implicit surface evolution technique is adopted for the reconstruction of the cortex in neonates. The performance of the method is investigated by performing a detailed landmark study. To facilitate study of cortical development, a cortical surface registration algorithm for aligning the cortical surface is developed. The method first inflates extracted cortical surfaces and then performs a non-rigid surface registration using free-form deformations (FFDs) to remove residual alignment. Validation experiments using data labelled by an expert observer demonstrate that the method can capture local changes and follow the growth of specific sulcus

First Natural Endocranial Cast of a Fossil Snake (Cretaceous of Patagonia, Argentina)

In this study, we describe a natural endocranial cast included in a partially preserved medium‐sized skull of the Upper Cretaceous South American snake Dinilysia patagonica. The endocast is composed of sedimentary filling of the cranial cavity in which the posterior brain, the vessels, the cranial nerves, and the inner ear surrounded by delicate semicircular canals, are represented. It is simple in form, with little differentiation between the three main areas (Forebrain, Midbrain, and Hindbrain), and without flexures. The nervous system is well preserved. The posterior brain surface is smooth, except for two small prominences that make up the cerebellum. A large inner ear is preserved on the right side; it consists of a voluminous central mass, the vestibule, which occupies most of the space defined by the three semicircular canals. In particular, the lateral semicircular canal is very close to the vestibule. This characteristic, in combination with the medium to large body size of Dinilysia, its large skull and dorsally exposed orbits, and vertebrae bearing a rather high neural spine on a depressed neural arch, suggests that this snake would have had a semifossorial lifestyle.Fil: Trivino, Laura Natalia. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Herpetologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Albino, Adriana Maria. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Dozo, Maria Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; ArgentinaFil: Williams, Jorge Daniel. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Herpetologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

COMPARATIVE ANALYZES OF ICG-VA, DIVA, FLOW 800 IMAGING IN CEREBROVASCULAR SURGERY

It is the most important to visualize cerebral vessels along with its surrounding structures during cerebrovascular surgery and it can be easier with real-time angiographic imaging. There are different kinds of indocyanine green dye based videoangiography are commonly used in cerebrovascular surgery. The objective. Comparative analyzing of ICG-AG, DIVA and Flow 800 color mapping in cerebrovascular surgery. Materials and methods. Real time surgery assessment of vascular and surrounding structures in 29 cerebral aneurysms clipping, one STA-MCA bypass and 2 carotid artery endarterectomy had been performed using ICG-VA, DIVA, flow 800 color mapping from August to October 2019. Result. In 23 cases in cerebral aneurysms clipping ICG-VA could not clearly visualize perforators compared to its’ better visualization by DIVA. In 3 cases, occlusion of perforators were assessed by DIVA after clip application which was solved by reapplication of surgical clips. In one STA-MCA bypass surgery, patency and sequences of blood inflow to cortical branches of MCA (M4) from recently anastomosed STA branches were assessed with ICG-VA, DIVA and Flow 800 color mapping. Visualization of the lack of blood flow and fluttering atherosclerotic plaques in carotid endarterectomy was observed by ICG-VA, DIVA, flow 800 mapping. Conclusion. In real time cerebrovascular surgery, ICG-VA, DIVA, and Flow 800 color mapping can be effective tool to better visualization of vascular and surrounding structures. Benefits of flow 800 color mapping outweighs the advantages of both ICG-VA and DIVA. However, DIVA is also better than ICG-VA to visualize

Imaging Informatics and the Human Brain Project: the Role of Structure, Review

(no abstract

Oncological, Vascular, and Spinal Uses of Contrast-Enhanced Ultrasound in Neurosurgery

Contrast-enhanced ultrasound (CEUS) is a real-time, feasible technique. Both intraoperatively and bedside, it satisfies the need for serial assessment and easy performability. Initially employed in neuro-oncology, it has recently overcome this first application. The chapter aims to give a comprehensive view of its use in oncological, vascular, and spinal neurosurgery. CEUS versatility across the aforementioned areas is analyzed, underlining its complementarity to other well-settled imaging techniques. Its major oncological (both cerebral and spinal) and vascular (including aneurysms, AVMs, dAVFs, carotid plaques, and stroke) application and state of the art are discussed. The chapter is focused on reporting CEUS advantages and disadvantages, giving an insight to future perspectives and applications

Spectral and Temporal Interrogation of Cerebral Hemodynamics Via High Speed Laser Speckle Contrast Imaging

Laser Speckle Contrast Imaging (LSCI) is a non-scanning wide field-of-view optical imaging technique specifically developed for cerebral blood flow (CBF) monitoring. In this project, a versatile Laser speckle contrast imaging system has been designed and developed to monitor CBF changes and examine the physical properties of cerebral vasculature during functional brain activation experiments. The hardware of the system consists of a high speed CMOS camera, a coherent light source, a trinocular microscope, and a PC that does camera controlling and data storage. The simplicity of the system’s hardware makes it suitable for biological experiments. In controlled flow experiments using a custom made microfluidic channel, the linearity of the CBF estimates was evaluated under high speed imaging settings. Under the camera exposure time setting in the range of tens of micro-seconds, results show a linear relationship between the CBF estimates and the flow rates within the microchannel. This validation permitted LSCI to be used in high frame rate imaging and the method is only limited by the camera speed. In an in vivo experiment, the amount of oxygen intake via breathing by a rat was reduced to 12% to induce the dilation of the vessels. Results demonstrated a positive correlation between the system’s CBF estimates and the pulse wave velocity derived from aortic blood pressure. To exemplify the instantaneous pulsatility flow study acquired at high sampling rate, a pulsatile cerebral blood flow analysis was conducted on two vessels, an arteriole and a venule. The pulsatile waveform results, captured under sampling rate close to 2000 Hz. The pulse of the arteriole rises 13ms faster than the pulse of the venule, and it takes 6ms longer for the pulse of the arteriole to fall below the lower fall-time boundary. By using the second order derivative (accelerated) CBF estimates, the vascular stiffness was evaluated. Results show the arteriole and the venule have increased-vascular-stiffness indices of 0.95 and 0.74. On the other side, the arteriole and the venule have decreased-vascular-stiffness indices of 0.125 and 0.35. Both vascular stiffness indices suggested that the wall of arteriole is more rigid than the venule. The proposed LSCI system can monitor the mean flow over function activation experiment, and the interrogation of blood flow in terms of physiological oscillations. The proposed vascular stiffness metrics for estimating the stroke preliminary symptom, may eventually lead to insights of stroke and its causes