Name: dti of the visual pathway - white matter tracts and cerebral lesions
Uploaded: 2014-08-26T15:00:00.000+00:00
Duration: 10 min 5 s
Description: Watch this Scientific Journal Video about DTI of the Visual Pathway - White Matter Tracts and Cerebral Lesions at JoVE.com

We would like to thank the whole Service of Neuroradiology. We would like to thank Lis Prussen for her work in the library.

NOT: Bu protokol Lüksemburg Centre Hospitalier de Lüksemburg yönergeleri takip eder. Nöroşirürji ve Görsel Yollarla için Difüzyon Tensor Görüntüleme hazırlanması 1. Takip <ol style="margin-left: 40px;"><li> En az bir gün 32 degrade yön ve tek b0-görüntü kullanılarak kesinlikle eksenel ameliyattan önce MR-tarama gerçekleştirin. Her an Nöroradyoloji birimi ile yakın temas halinde tutunuz. NOT: ameliyat sonrası görüntüler operasyon öncesi gibi aynı nöroradyolog açık olun. </li><li> 3 Tesla MR kullanarak, bir 3DT1 ağırlıklı ve DTI-dizi taramalar yapar. De ameliyat sonrası 3DT1 ağırlıklı dizisi gerçekleştirin. </li></ol> 2. Planlama İstasyonunu kullanan <ol><li> Tıp (DICOM) dijital görüntüleme ve haberleşme T2 ağırlıklı, 3DT1 ağırlıklı ve DTI-dizi tarama verilerini aktarın. Bu prosedür 7 dakika kadar sürer. NOT: Don `t befo prosedürü durdurmakyeniden tüm dizileri transfer olan. Bu durdurmak ve ameliyat tarihine bağlı olarak daha sonra devam etmek mümkündür. </li><li> Cerrahi navigasyon sistemi programını açın. Dosya ve ardından İthalat DICOM tıklayın. Yukarıda belirtilen tüm dizileri için bu işlemi üç kez tekrarlayın. <ol><li> Görüntülemek için Ekle &#39;yi tıklatın. Ayrı ayrı, her sekansı ekleyin. Don `t Manzaralı devam etmek deneyin. </li></ol></li><li> Araçlar tıklayın. Açık DTI tensör hazırlanması. Ekranın ortasında yeni bir pencere gözlemleyin. </li><li> Dört aşağıdaki adımları tamamlayın. <ol><li> İlk adım olarak Degrade Atama gerçekleştirin. <ol><li> Pencerenin sağ alt 1000 s 800 / mm² b-değeri değiştirin. </li><li> Pencerenin sağ üst Eşik ayarlayın. Basit bir numara yazarken veya imleci hareket ettirerek elle bunu yapmak. 20 kabul edilebilir bir değeri olabilir. Bu kişisel bir deneyimdir ve bu zorunlu değildir. </li></ol></li><li> İkinci adım olarak Degrade Kayıt gerçekleştirin. <ol> &lt;li&gt; düğmesini Tüm Oto tıklayın. Bu işlem 5 dakika kadar sürer. </li><li> Tüm Kayıtlar doğrulayın tıklayın. Kayıtları doğrulayarak olmadan devam etmek mümkün değildir. </li></ol></li><li> Üçüncü adım olarak Coregistration gerçekleştirin. <ol><li> Coregister MR1&#39;in ve elle b0 MR2 görüntüler. Sonunda tüm Kayıtları doğrulayın. NOT: Bu otomatik olarak bu adımı gerçekleştirmek mümkündür. Bununla birlikte, sonuçlar, sonunda her zaman tatmin edici olmayabilir. </li></ol></li><li> Dördüncü ve son aşama olarak tensör hesabı yapmak, <ol><li> Emin FA / Aralık / ADC üzerinde olduğundan emin olun. Eğer AÇIK tıklatın. </li><li> Compute tıklayın. Bu prosedür sadece birkaç saniye sürer. </li></ol></li></ol></li><li> Tüm verileri kaydetmek ve fibertracking devam. Her şeyi kaydetmeden bitmiyor. </li></ol> 3. Fibertracking NOT: Görsel yolunun anatomik bilgisi başarılı bir sonuç için çok önemlidir. <ol style = &quot;margin-left: 40px;&quot;&gt; <li> Lifler gitmek zorunda üç önemli noktaları bulmak için hazırlayın. </li><li> Anatomik bilgiyi kullanarak optik kiazma belirleyin. <ol><li> Bir başlangıç ​​noktası olarak bir ROI kullanın ve lifler üzerinden gidelim. ROI hekim tarafından belirlenir. </li><li> Alternatif segment şüpheli bölge. Alt Kesimlemeyi sol tıklatın ve yeni bir pencere açılacaktır. Parçalara alanları anatomik alanları olarak tanımlanır. <ol><li> Elle bölgeyi boyayın. Bütün optik kiazma dahil aşağı yukarı ilerleyin ve. Prosedürü kaydedin ve geri gitmek. </li></ol></li><li> Ilgi bölgesi ya da parçalara ayrılmış alan ya da her ikisi ya da lifler takip edin. </li><li> Lifler görsel yolunun ikinci önemli nokta, sol genikulate çekirdeğini (LGN&#39;nin), ulaşmak. En geniş sahte yolları riski açısı çok yüksek ise, ile artacak 50 idi. <ol><li> Kiyazmanın gösterildiği gibi Lgn segmente bir olasılık vardırve daha sonra lifler izler. Kiyazmanın ya da tam tersi olarak Lgn ve bitiş çalıştırmak optik chiasm, parça lifleri segmente ettikten sonra. </li></ol></li><li> Segment görsel korteks. Kiazmada durumunda olduğu gibi devam edin. 3DT1-ağırlıklı görüntü 160 dilimler içeriyorsa bu biraz zaman alabilir. </li><li> Lgn için görsel korteks lifleri izlemek. Bir de görsel kortekse Lgn onları izlemek mümkün. </li><li> Görsel korteks, tümör veya ödem tarafından işgal edilirse, bir bölümlere ayrılmış alanının yerine bir ilgi alanı kullanmak ve ardından Lgn bir yönde uzanır lifleri sağlar. NOT: ödem sonra görsel korteksi istila olabilir bazen kesimliyse sonra görsel korteks bilgisayar aralarında ayrım yapamam çünkü tamamen segmented mümkün olmayabilir. Neden gerekli olduğunu That`s bir yatırım getirisi koymak. </li><li> Diğer yarımkürede için her şeyi tekrarlayın. </li><li> İlk sağlıklı hemisfer ile başlayın. NOT: Itmümkün de başka biri ile başlamak için ama bu durum hakkında bir fikir ilk haline ilk sağlıklı yarımkürenin lifleri izlemek daha kolay olabilir. Bu sadece bir tavsiyedir, zorunlu değildir. </li></ol></li><li> Segment serebral lezyon ve ödem. 3.2.2 Yukarıda belirtildiği gibi devam edin. <ol><li> Daha iyi ayırt etmek için her segmente alanda veya lezyon için bir renk atayın. </li></ol></li><li> Beklenmedik olaylar durumunda ya da acil bir durumda her adımdan sonra prosedürü kaydedin. </li><li> Yerel tüm verileri. Doğrudan ameliyathaneye ihracat mümkündür ancak tavsiye olmuyormuş. <ol><li> Basın Dosya ve ardından İhracat 3D nesneler. Sadece Navigasyon Sınav ihracat emin olun. </li><li> Don `t Hibrid Sınavı ihracat. </li></ol></li><li> Kranial girin. Doğru hasta seçin, daha sonra Stealthmerge basın. Referans sınavı olarak 3DT1 ağırlıklı görüntüleri seçin. </li><li> 3D modelini oluşturun ve her şeyi yerleştirin. </li><li> Veri alma in operasyon odası. </li></ol>

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The authors declare that they have no competing financial interests.

DTI vivo 8 beyaz cevher yolları görselleştirmek için nöroşirürjiyene sağlayan bir tekniktir. Görsel yolu, bu yolları biridir. Bu yöntem, bu tekniğin bazı sınırlamalar hala var olduğunu söylemek zorunda beynin beliğ bölgelerini ilgilendiren lezyonları olan hastaların tedavisi ile ilgili yeni olanaklar hekimlere sağlasa. Ilk ve en belirgin zorluk soruşturma altında 4 önemli bir konudur beyin kayması vardır. Tümör veya ameliyat öncesi gibi aynı koşulla...

Difüzyon tensör görüntüleme (DTG), insan beyninde 1 non-invaziv WMT canlandıracak için kullanılır. Ameliyat sırasında 1 beyin alanları anlamlı zarar verme riskini azaltmak için, son on yıl içinde kullanılmıştır. DTI görsel yolu göstermeye Mart 2012 ve Ocak 2014 tarihleri ​​arasında elli hastada uygulandı. DTI beyaz cevher yollarının anatomik konumu hakkında önemli bilgiler vererek ameliyat sırasında beynin beliğ alanlarının korunmasını arttırmak olabilir. Bu kompleks beyin lezyonları 1 rezeksiyonu için stratejik planlamasına dahil edilmiştir. DTI, tohum hacimleri ve sonuçları 12 yorumlama yerleştirme parametreleri için bir standart yoktur çünkü Ancak, görsel yolunun canlandırdığı bir sorun olmaya devam etmektedir. Farklı algoritmalar kadar 19-21 uygulanmıştır. Bazı yaklaşımlar deterministik yöntemleri üzerinde yoğunlaşmıştır 19, 22-25. Diğerleri 26,27,29, olasılık yöntemleri kullanılarak yapılmıştır. Daha yakın zamanlarda, Q-top tensör alanlarını, difüzyon spektrum görüntüleme ve Yüksek Açısal Çözünürlük Difüzyon Görüntüleme (Hardi) kullanılmaktadır teknikler kullanarak başkalarının görme yolları 1,13-15,18 arasında beyaz cevher risaleler tasvir. Bununla birlikte, HARDI için gereken süre 45 dakika önemli ölçüde daha uzun olan, yazılım ticari olarak mevcut değildir ve bilimsel uygulamalar 18 vurgulamaktadır. HARDI için öğretim süresi uzun DTI 18 için daha görünüyor. Sunulan protokol kolay uygulanabilir olması ve postoperatif sonucu morbidite önlemek ve iyileştirmek için nöroşirurji operasyonlarında günlük rutin için kullanılabilir. Bu protokol için ek süre diğer protokol 1,9,12,16 önemli ölçüde daha hızlı daha az 9 dk. Birçok gelişmiş algoritmalar kağıt kısıtlar son zamanlarda geliştirilen bu gerçeği kabulkendisi, bir ticari olarak temin edilebilir ve FDA onaylı yazılım kullanımı ile ilgilidir. Bununla birlikte, göz önüne, yukarıda belirtilen bu tekniğin kısıtlamaları almak için zorunludur.

<table><tbody><tr><td>3-Tesla-MRI</td><td>General Electric</td><td>Signa LX version 9.1</td><td></td></tr><tr><td>Surgical Navigation System Program</td><td>Medtronic</td><td>9734478</td><td></td></tr><tr><td>Surgical Navigation System Program</td><td>Medtronic</td><td>4500810331&amp;nbsp; 20016318</td><td></td></tr></tbody></table>

dti of the visual pathway - white matter tracts and cerebral lesions

<html> DTI non-invaziv difüzyon ölçümleri kullanılarak sağlıklı ve sağlıklı olmayan hastalarda beyaz cevher yolları (WMT) tanımlayan bir tekniktir. Görme yollarının (VP) benzer, WMT klasik MR veya intra-operatif mikroskop ile görülebilir değildir. DIT Bu WMT bitişik lezyonları çıkarırken beyin cerrahları VP yıkımı önlemeye yardımcı olacaktır. Biz bir 3DT1 ağırlıklı dizisi kullanıldı gezinmek için Ocak 2014 Mart 2012 tarihleri ​​arasında ameliyat öncesi ve sonrası elli hasta üzerinde DTI gerçekleştirdik. Ayrıca, T2 ağırlıklı ve DTI-dizileri gerçekleştirildi. 200 x 200 mm, dilim kalınlığı: 2 mm, ve satın alma matriks: 96 x 96 2 x 2 x 2 mm yaklaşık izotropik vokselleri veren kullanılan parametreler, FOV vardı. Eksenel MR 32 degrade yönünü ve bir b0-görüntü kullanılarak gerçekleştirilmiştir. Biz 2 hızlanma faktör ve 800 s / mm²&#39;ye b-değeri ile Eko-Planar-Görüntüleme (EPI) ve VARLIĞI paralel görüntüleme kullanılır. Tarama süresi az 9 dk. ent &quot;&gt; FDA sürekli takibi (AÇEP) ile lif atama olarak bilinen basit bir lif izleme yaklaşım kullanır cerrahi navigasyon sistemi programını onayladı kullanılarak işlendi elde DTI-veri. Bu ilgi bölgeler arasındaki çizgilerin yayılması (dayalıdır Bir hekim tarafından tanımlanır ROI). 50 maksimum açısı, FA lar Traktografinin için kullanılan parametreler vardı 0.10 değer ve 0.20 mm ² / &#39;ADC durdurma değerini başlar. Bu tekniğin bazı sınırlamalar vardır. Sınırlı alma zamanı çerçevesi görüntü kalitesinde ödünleşimleri zorlar. Ihmal edilmemesi gereken başka bir önemli nokta ameliyat sırasında beyin değişikliğidir. Ikincisi intra-operatif MR için de yararlı olabilir. Ayrıca yanlış pozitif veya yanlış negatif yolları riski kesin sonuçları tehlikeye atabilir dikkate alınmalıdır.

<html> Bu protokol yeterince VP büyük parçalar canlandıracak doktora sağlar. Bu anlamlı alanların yanındaki beyin lezyonu olan hastalarda bir hasarı önlemek için zaman küçük bir miktarı ile de kullanılabilir. Ameliyat sonrası kontroller de iyi sonuçlar göstermektedir. Hasta bir glioblastoma çalıştırılabilir sonra VP Şekil 7&#39;de tasvir edilir. 2 glioblastoma nüks sonra VP göstermektedir. Yazarlar önemli bir sorun olmaya devam Meyer döngü t...

Watch this Scientific Journal Video about DTI of the Visual Pathway - White Matter Tracts and Cerebral Lesions at JoVE.com

DTI of the Visual Pathway - White Matter Tracts and Cerebral Lesions

Difüzyon tensör görüntüleme (DTG) görsel yolunun büyük parçalar tasvir etmeye yapıldı. Amaç FDA hastalarda görme yolunun postoperatif hasarı azaltmak için denemek için günlük rutin için standart olarak kullanılan ticari iş istasyonu onaylı kullanmak olmuştur.

Görsel yola¤ DTI - Beyaz Cevher Yollar ve Serebral Lezyonlar

DTI is a technique that identifies white matter tracts (WMT) non-invasively in healthy and non-healthy patients using diffusion measurements. Similar to ...

dti-of-the-visual-pathway-white-matter-tracts-and-cerebral-lesions

Research

JoVE Journal

Medicine

13.9K Görüntüleme.  Centre Hospitalier de Luxembourg.  Difüzyon tensör görüntüleme (DTG) görsel yolunun büyük parçalar tasvir etmeye yapıldı. Amaç FDA hastalarda görme yolunun postoperatif hasarı azaltmak için denemek için günlük rutin için standart olarak kullanılan ticari iş istasyonu onaylı kullanmak olmuştur. 

Video: DTI of the Visual Pathway - White Matter Tracts and Cerebral Lesions

Dissection of Human Vitreous Body Elements for Proteomic Analysis

The vitreous is an optically clear, collagenous extracellular matrix that fills the inside of the eye and overlies the retina. 1,2 Abnormal interactions between vitreous substructures and the retina underlie several vitreoretinal diseases, including retinal tear and detachment, macular pucker, macular hole, age-related macular degeneration, vitreomacular traction, proliferative vitreoretinopathy, proliferative diabetic retinopathy, and inherited vitreoretinopathies. 1,2 The molecular composition of the vitreous substructures is not known. Since the vitreous body is transparent with limited surgical access, it has been difficult to study its substructures at the molecular level. We developed a method to separate and preserve these tissues for proteomic and biochemical analysis. The dissection technique in this experimental video shows how to isolate vitreous base, anterior hyaloid, vitreous core, and vitreous cortex from postmortem human eyes. One-dimensional SDS-PAGE analyses of each vitreous component showed that our dissection technique resulted in four unique protein profiles corresponding to each substructure of the human vitreous body. Identification of differentially compartmentalized proteins will reveal candidate molecules underlying various vitreoretinal diseases.

This video shows an effective technique for differentiating and dissecting the various semi-transparent structures of the human vitreous body in post mortem eyes.

Proteomik Analizi İnsan Vitreus Gövde Elemanları diseksiyonu

The vitreous is an optically clear, collagenous extracellular matrix that fills the inside of the eye and overlies the retina. 1,2 Abnormal interactions ...

Tıp

The Application Of Permanent Middle Cerebral Artery Ligation in the Mouse

Focal cerebral ischemia is among the most common type of stroke seen in patients. Due to the clinical significance there has been a prolonged effort to develop suitable animal models to study the events that unfold during ischemic insult. These techniques include transient or permanent, focal or global ischemia models using many different animal models, with the most common being rodents.
The permanent MCA ligation method which is also referred as pMCAo in the literature is used extensively as a focal ischemia model in rodents 1-6. This method was originally described for rats by Tamura et al. in 1981 7. In this protocol a craniotomy was used to access the MCA and the proximal regions were occluded by electrocoagulation. The infarcts involve mostly cortical and sometimes striatal regions depending on the location of the occlusion. This technique is now well established and used in many laboratories 8-13. Early use of this technique led to the definition and description of &#x201C;infarct core&#x201D; and &#x201C;penumbra&#x201D; 14-16, and it is often used to evaluate potential neuroprotective compounds 10, 12, 13, 17. Although the initial studies were performed in rats, permanent MCA ligation has been used successfully in mice with slight modifications 18-20 .
This model yields reproducible infarcts and increased post-survival rates. Approximately 80% of the ischemic strokes in humans happen in the MCA area 21 and thus this is a very relevant model for stroke studies. Currently, there is a paucity of effective treatments available to stroke patients, and thus there is a need for good models to test potential pharmacological compounds and evaluate physiological outcomes. This method can also be used for studying intracellular hypoxia response mechanisms in vivo. 
Here, we present the MCA ligation surgery in a C57/BL6 mouse. We describe the pre-surgical preparation, MCA ligation surgery and 2,3,5 Triphenyltetrazolium chloride (TTC) staining for quantification of infarct volumes.

Middle cerebral artery (MCA) ligation is a technique to study focal cerebral ischemia in animal models. In this method, the middle cerebral artery is exposed by craniotomy and ligated by cauterization. This method gives highly reproducible infarct volumes and increased post-operative survival rates compared to other methods available.

Fare Daimi Orta Serebral Arter ligasyon Of Uygulama

Focal cerebral ischemia is among the most common type of stroke seen in patients. Due to the clinical significance there has been a prolonged effort to ...

Probing the Brain in Autism Using fMRI and Diffusion Tensor Imaging

Newly emerging theories suggest that the brain does not function as a cohesive unit in autism, and this discordance is reflected in the behavioral symptoms displayed by individuals with autism. While structural neuroimaging findings have provided some insights into brain abnormalities in autism, the consistency of such findings is questionable. Functional neuroimaging, on the other hand, has been more fruitful in this regard because autism is a disorder of dynamic processing and allows examination of communication between cortical networks, which appears to be where the underlying problem occurs in autism. Functional connectivity is defined as the temporal correlation of spatially separate neurological events1. Findings from a number of recent fMRI studies have supported the idea that there is weaker coordination between different parts of the brain that should be working together to accomplish complex social or language problems2,3,4,5,6. One of the mysteries of autism is the coexistence of deficits in several domains along with relatively intact, sometimes enhanced, abilities. Such complex manifestation of autism calls for a global and comprehensive examination of the disorder at the neural level. A compelling recent account of the brain functioning in autism, the cortical underconnectivity theory,2,7 provides an integrating framework for the neurobiological bases of autism. The cortical underconnectivity theory of autism suggests that any language, social, or psychological function that is dependent on the integration of multiple brain regions is susceptible to disruption as the processing demand increases. In autism, the underfunctioning of integrative circuitry in the brain may cause widespread underconnectivity. In other words, people with autism may interpret information in a piecemeal fashion at the expense of the whole. Since cortical underconnectivity among brain regions, especially the frontal cortex and more posterior areas 3,6, has now been relatively well established, we can begin to further understand brain connectivity as a critical component of autism symptomatology.
A logical next step in this direction is to examine the anatomical connections that may mediate the functional connections mentioned above. Diffusion Tensor Imaging (DTI) is a relatively novel neuroimaging technique that helps probe the diffusion of water in the brain to infer the integrity of white matter fibers. In this technique, water diffusion in the brain is examined in several directions using diffusion gradients. While functional connectivity provides information about the synchronization of brain activation across different brain areas during a task or during rest, DTI helps in understanding the underlying axonal organization which may facilitate the cross-talk among brain areas. This paper will describe these techniques as valuable tools in understanding the brain in autism and the challenges involved in this line of research.

Neuroimaging techniques, such as functional MRI and Diffusion Tensor Imaging have become increasingly useful in characterizing the cognitive and neural deficits in autism. An examination of brain connectivity in autism at a network level along with adaptations for scanning children with developmental disabilities is presented.

FMRI ve Difüzyon Tensör Görüntüleme Otizm Beyin problama

Newly emerging theories suggest that the brain does not function as a cohesive unit in autism, and this discordance is reflected in the behavioral ...

Co-analysis of Brain Structure and Function using fMRI and Diffusion-weighted Imaging

The study of complex computational systems is facilitated by network maps, such as circuit diagrams. Such mapping is particularly informative when studying the brain, as the functional role that a brain area fulfills may be largely defined by its connections to other brain areas. In this report, we describe a novel, non-invasive approach for relating brain structure and function using magnetic resonance imaging (MRI). This approach, a combination of structural imaging of long-range fiber connections and functional imaging data, is illustrated in two distinct cognitive domains, visual attention and face perception. Structural imaging is performed with diffusion-weighted imaging (DWI) and fiber tractography, which track the diffusion of water molecules along white-matter fiber tracts in the brain (Figure 1). By visualizing these fiber tracts, we are able to investigate the long-range connective architecture of the brain. The results compare favorably with one of the most widely-used techniques in DWI, diffusion tensor imaging (DTI). DTI is unable to resolve complex configurations of fiber tracts, limiting its utility for constructing detailed, anatomically-informed models of brain function. In contrast, our analyses reproduce known neuroanatomy with precision and accuracy. This advantage is partly due to data acquisition procedures: while many DTI protocols measure diffusion in a small number of directions (e.g., 6 or 12), we employ a diffusion spectrum imaging (DSI)1, 2 protocol which assesses diffusion in 257 directions and at a range of magnetic gradient strengths. Moreover, DSI data allow us to use more sophisticated methods for reconstructing acquired data. In two experiments (visual attention and face perception), tractography reveals that co-active areas of the human brain are anatomically connected, supporting extant hypotheses that they form functional networks. DWI allows us to create a "circuit diagram" and reproduce it on an individual-subject basis, for the purpose of monitoring task-relevant brain activity in networks of interest.

We describe a novel approach for simultaneous analysis of brain function and structure using magnetic resonance imaging (MRI). We assess brain structure with high-resolution diffusion-weighted imaging and white-matter fiber tractography. Unlike standard structural MRI, these techniques allow us to directly relate anatomical connectivity to functional properties of brain networks.

FMRI ve difüzyon ağırlıklı görüntüleme ile Beyin Yapısı ve Fonksiyonu Co-analizi

The study of complex computational systems is facilitated by network maps, such as circuit diagrams. Such mapping is particularly informative when ...

Nörobilim

Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases

Diffusion tensor imaging (DTI) techniques provide information on the microstructural processes of the cerebral white matter (WM) in vivo. The present applications are designed to investigate differences of WM involvement patterns in different brain diseases, especially neurodegenerative disorders, by use of different DTI analyses in comparison with matched controls. 	
DTI data analysis is performed in a variate fashion, i.e. voxelwise comparison of regional diffusion direction-based metrics such as fractional anisotropy (FA), together with fiber tracking (FT) accompanied by tractwise fractional anisotropy statistics (TFAS) at the group level in order to identify differences in FA along WM structures, aiming at the definition of regional patterns of WM alterations at the group level. Transformation into a stereotaxic standard space is a prerequisite for group studies and requires thorough data processing to preserve directional inter-dependencies. The present applications show optimized technical approaches for this preservation of quantitative and directional information during spatial normalization in data analyses at the group level. On this basis, FT techniques can be applied to group averaged data in order to quantify metrics information as defined by FT. Additionally, application of DTI methods, i.e. differences in FA-maps after stereotaxic alignment, in a longitudinal analysis at an individual subject basis reveal information about the progression of neurological disorders. Further quality improvement of DTI based results can be obtained during preprocessing by application of a controlled elimination of gradient directions with high noise levels.	
In summary, DTI is used to define a distinct WM pathoanatomy of different brain diseases by the combination of whole brain-based and tract-based DTI analysis.

Diffusion tensor imaging (DTI) basically serves as an MRI-based tool to identify in vivo the microstructure of the brain and pathological processes due to neurological disorders within the cerebral white matter. DTI-based analyses allow for application to brain diseases both at the group level and in single subject data.

Nörodejeneratif Hastalıkların Analizi Difüzyon Tensör Manyetik Rezonans Görüntüleme

Diffusion tensor imaging (DTI) techniques provide information on the microstructural processes of the cerebral white matter (WM) in vivo. The present ...

Measuring Connectivity in the Primary Visual Pathway in Human Albinism Using Diffusion Tensor Imaging and Tractography

In albinism, the number of ipsilaterally projecting retinal ganglion cells (RGCs) is significantly reduced. The retina and optic chiasm have been proposed as candidate sites for misrouting. Since a correlation between the number of lateral geniculate nucleus (LGN) relay neurons and LGN size has been shown, and based on previously reported reductions in LGN volumes in human albinism, we suggest that fiber projections from LGN to the primary visual cortex (V1) are also reduced. Studying structural differences in the visual system of albinism can improve the understanding of the mechanism of misrouting and subsequent clinical applications. Diffusion data and tractography are useful for mapping the OR (optic radiation). This manuscript describes two algorithms for OR reconstruction in order to compare brain connectivity in albinism and controls.An MRI scanner with a 32-channel head coil was used to acquire structural scans. A T1-weighted 3D-MPRAGE sequence with 1 mm3 isotropic voxel size was used to generate high-resolution images for V1 segmentation. Multiple proton density (PD) weighted images were acquired coronally for right and left LGN localization. Diffusion tensor imaging (DTI) scans were acquired with 64 diffusion directions. Both deterministic and probabilistic tracking methods were run and compared, with LGN as the seed mask and V1 as the target mask. Though DTI provides relatively poor spatial resolution, and accurate delineation of OR may be challenging due to its low fiber density, tractography has been shown to be advantageous both in research and clinically. Tract based spatial statistics (TBSS) revealed areas of significantly reduced white matter integrity within the OR in patients with albinism compared to controls. Pairwise comparisons revealed a significant reduction in LGN to V1 connectivity in albinism compared to controls. Comparing both tracking algorithms revealed common findings, strengthening the reliability of the technique.

This manuscript describes deterministic and probabilistic algorithms for white matter (WM) reconstruction, used to examine differences in optic radiation (OR) connectivity between albinism and controls. Although probabilistic tractography follows the true course of nerve fibers more closely, deterministic tractography was run to compare the reliability and reproducibility of both techniques.

Difüzyon tensör görüntüleme ve traktografi kullanarak İnsan Albinizmi İlköğretim Görsel Yolu&#39;ndaki Bağlantı Ölçme

In albinism, the number of ipsilaterally projecting retinal ganglion cells (RGCs) is significantly reduced. The retina and optic chiasm have been proposed ...

Fiber Connections of the Supplementary Motor Area Revisited: Methodology of Fiber Dissection, DTI, and Three Dimensional Documentation

The purpose of this study is to show the methodology for the examination of the white matter connections of the supplementary motor area (SMA) complex (pre-SMA and SMA proper) using a combination of fiber dissection techniques on cadaveric specimens and magnetic resonance (MR) tractography. The protocol will also describe the procedure for a white matter dissection of a human brain, diffusion tensor tractography imaging, and three-dimensional documentation. The fiber dissections on human brains and the 3D documentation were performed at the University of Minnesota, Microsurgery and Neuroanatomy Laboratory, Department of Neurosurgery. Five postmortem human brain specimens and two whole heads were prepared in accordance with Klingler's method. Brain hemispheres were dissected step by step from lateral to medial and medial to lateral under an operating microscope, and 3D images were captured at every stage. All dissection results were supported by diffusion tensor imaging. Investigations on the connections in line with Meynert's fiber tract classification, including association fibers (short, superior longitudinal fasciculus I and frontal aslant tracts), projection fibers (corticospinal, claustrocortical, cingulum, and frontostriatal tracts), and commissural fibers (callosal fibers) were also conducted.

The purpose of this study is to show each step of the fiber dissection technique on human cadaveric brains, the 3D documentation of these dissections, and the diffusion tensor imaging of the anatomically dissected fiber pathways.

Ek Motor Alanında Fiber Bağlantıları Gözden Geçirildi: Fiber Disseksiyonu Metodolojisi, DTI ve Üç Boyutlu Dokümantasyon

The purpose of this study is to show the methodology for the examination of the white matter connections of the supplementary motor area (SMA) complex ...

Diffusion Tensor Magnetic Resonance Imaging in Chronic Spinal Cord Compression

Chronic spinal cord compression is the most common cause of spinal cord impairment in patients with nontraumatic spinal cord damage. Conventional magnetic resonance imaging (MRI) plays an important role in both confirming the diagnosis and evaluating the degree of compression. However, the anatomical detail provided by conventional MRI is not sufficient to accurately estimate neuronal damage and/or assess the possibility of neuronal recovery in chronic spinal cord compression patients. In contrast, diffusion tensor imaging (DTI) can provide quantitative results according to the detection of water molecule diffusion in tissues. In the present study, we develop a methodological framework to illustrate the application of DTI in chronic spinal cord compression disease. DTI fractional anisotropy (FA), apparent diffusion coefficients (ADCs), and eigenvector values are useful for visualizing microstructural pathological changes in the spinal cord. Decreased FA and increases in ADCs and eigenvector values were observed in chronic spinal cord compression patients compared to healthy controls. DTI could help surgeons understand spinal cord injury severity and provide important information regarding prognosis and neural functional recovery. In conclusion, this protocol provides a sensitive, detailed, and noninvasive tool to evaluate spinal cord compression.

Here, we present a protocol for the application of diffusion tensor imaging parameters to evaluate spinal cord compression.

Kronik omurilik kompresyonu difüzyon tensor manyetik rezonans görüntüleme

Chronic spinal cord compression is the most common cause of spinal cord impairment in patients with nontraumatic spinal cord damage. Conventional magnetic ...

Advanced Diffusion Imaging in The Hippocampus of Rats with Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) is the most common type of acquired brain injury. Since patients with traumatic brain injury show a tremendous variability and heterogeneity (age, gender, type of trauma, other possible pathologies, etc.), animal models play a key role in unraveling factors that are limitations in clinical research. They provide a standardized and controlled setting to investigate the biological mechanisms of injury and repair following TBI. However, not all animal models mimic the diffuse and subtle nature of mTBI effectively. For example, the commonly used controlled cortical impact (CCI) and lateral fluid percussion injury (LFPI) models make use of a craniotomy to expose the brain and induce widespread focal trauma, which are not commonly seen in mTBI. Therefore, these experimental models are not valid to mimic mTBI. Thus, an appropriate model should be used to investigate mTBI. The Marmarou weight drop model for rats induces similar microstructural alterations and cognitive impairments as seen in patients who sustain mild trauma; therefore, this model was selected for this protocol. Conventional computed tomography and magnetic resonance imaging (MRI) scans commonly show no damage following a mild injury, because mTBI induces often only subtle and diffuse injuries. With diffusion weighted MRI, it is possible to investigate microstructural properties of brain tissue, which can provide more insight into the microscopic alterations following mild trauma. Therefore, the goal of this study is to obtain quantitative information of a selected region-of-interest (i.e., hippocampus) to follow up disease progression after obtaining a mild and diffuse brain injury.

The overall goal of this procedure is to obtain quantitative microstructural information of the hippocampus in a rat with mild traumatic brain injury. This is done using an advanced diffusion-weighted magnetic resonance imaging protocol and region-of-interest based analysis of parametric diffusion maps.

Hafif Travmatik Beyin Hasarı Olan Sıçanların Hipokampuslarında İleri Difüzyon Görüntüleme

Mild traumatic brain injury (mTBI) is the most common type of acquired brain injury. Since patients with traumatic brain injury show a tremendous ...

Using Diffusion Tensor Imaging in Traumatic Brain Injury

Source: Laboratories of Jonas T. Kaplan and Sarah I. Gimbel&#8212;University of Southern California
Traditional brain imaging techniques using MRI are very good at visualizing the gross structures of the brain. A structural brain image made with MRI provides high contrast of the borders between gray and white matter, and information about the size and shape of brain structures. However, these images do not detail the underlying structure and integrity of white matter networks in the brain, which consist of axon bundles that interconnect local and distant brain regions.
Diffusion MRI uses pulse sequences that are sensitive to the diffusion of water molecules. By measuring the direction of diffusion, it is possible to make inferences about the structure of white matter networks in the brain. Water molecules within an axon are constrained in their movements by the cell membrane; instead of randomly moving in every direction with equal probability (isotropic movement), they are more likely to move in certain directions, in parallel with the axon (anisotropic movement; Figure 1). Therefore, measures of diffusion anisotropy are thought to reflect properties of the white matter such as fiber density, axon thickness, and degree of myelination. One common measure is fractional anisotropy (FA). FA values range from 0, which represents completely isotropic movement, to 1, reflecting maximum anisotropy.
<img alt="Figure 1" src="/files/ftp_upload/10276/10276fig1.jpg" /> 
Figure 1: Diffusion anisotropy. When the direction of diffusion is unconstrained and random, movement is measured in all directions equally. This is isotropic diffusion (A). When water molecules are contained within the axon of a neuron, diffusion is anisotropic, tending to occur more frequently along the direction of the axon (B). <a href="http://www.jove.com/files/ftp_upload/10276/10276fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
In this experiment we will use diffusion tensor imaging (DTI) to measure white matter integrity in traumatic brain injury (TBI). TBI occurs when an external force injures the brain, such as a blow to the head or a sudden movement like the kind that might occur in a car accident. This type of brain injury from mechanical forces is associated with diffuse axonal injury-damage to white matter throughout the brain. Because it is an injury affecting white matter integrity, standard neuroimaging techniques may not reveal the damage. However, measures of diffusion are especially sensitive to these anatomical changes. Following a study by Kraus et al.1, we compare a group of healthy controls to a group of people with TBI and use diffusion imaging to measure the effect of TBI on cerebral white matter. Furthermore, we will test the relationship between white matter integrity and cognitive function using an attention task.2 This study uses a region of interest (ROI) approach focusing on three white matter tracts: the splenium of the corpus callosum, the anterior corona radiata, and the superior longitudinal fasciculus (Figure 2).
<img alt="Figure 2" src="/files/ftp_upload/10276/10276fig2.jpg" /> 
Figure 2: Regions of interest. The three ROIs, defined from the ICBM DTI-81 atlas, are shown here in horizontal slices through the brain. In green is the splenium of the corpus callosum. The splenium is the most posterior part of the corpus callosum. In blue is the anterior corona radiata. The superior longitudinal fasciculus is shown in red. <a href="http://www.jove.com/files/ftp_upload/10276/10276fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Diffusion Tensor Imaging in Traumatic Brain Injury

Source: Laboratories of Jonas T. Kaplan and Sarah I. Gimbel&#8212;University of Southern California
Traditional brain imaging techniques using MRI are ...