Name: phase contrast magnetic resonance imaging in the rat common carotid artery
Uploaded: 2018-09-05T15:30:00.000+00:00
Duration: 7 min 2 s
Description: Watch this Scientific Journal Video about Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery at JoVE.com

Bu eser Bakanlığı Bilim ve teknoloji, Tayvan, grant MOST-105-2314-B-039-044-MY2 sayısı altında gelen hibe tarafından desteklenmiştir.

Kurumsal Bakım ve kullanım Komiteleri (IACUC) Çin Tıp Üniversitesi'nin tüm prosedürleri onayladı.
1. hayvan hazırlık ve izleme
<ol><li>Cüzdan, anahtarlar, kredi kartı, vb gibi tüm manyetik olarak duyarlı nesneler MRI tarama için hayvan hazırlık başlıyor önce tarayıcı oda dışında bırakın.</li>
	<li>Başlangıçta bir indüksiyon kutusuna gerektiği gibi 3-5 min için %5 isoflurane (ISO) ve oksijen (2 L/dak) karışımı kullanarak fare (2 aylık erkek Sprague-Dawley (SD) fare, 280-350 g) anestezi.</li>
	<li>Hayvan yaslanmış ve bir kuyruk veya ayak çimdik yanıt sergiler, ISO yönetim durdurma ve hayvan tarama odasına aktar.</li>
	<li>Fare kafa ilk yüzükoyun MRI yatakta yerleştirin ve anestezi korumak için bir burun konisi aygıtı üzerinden % 2-3 ISO teslim.</li>
	<li>Solunum solunum yastık algılayıcıyı hayvanın gövde altında yerleştirerek izlemek.</li>
	<li>Sensör bir solunum sistemi ve solunum hızı arasında 40-50 vuruş / dakika (bpm) için onay bağlayın.</li>
	<li>PC-MRI toplama, cine geçitli bir elektrot doğru forepaw koyun ve sol arka pençe, sırasıyla (Şekil 1a).</li>
	<li>Elektrokardiyografi (EKG) kabloları birlikte twist.</li>
	<li>Bir kafa tutucu kulak bar ve bir ısırık bar ile kafa hareketi kısıtlamak için hayvan güvenliğini sağlamak için kullanın.</li>
	<li>Sistem veya gazlı bez yastıkları ısıtma sıcak bir hava içinde iken mıknatıs vücut ısısını korumak için kullanın.</li>
	<li>R-dalga ECG monitörde (Şekil 1b) açık olduğundan emin olun ve hayvanın tarayıcıya yerleştirin. Görüntü birimi bobin tarafından alınan hayvanın boyun üst yüzey bobin yerleştirmek için gerek yoktur.</li>
</ol>2. Mr'ı edinme
<ol><li>% 2 – 3 ISO tüm görüntüleme işlemi sırasında anestezi korumak için kullanın. Sürekli olarak fizyolojik tepkiler ve tutmak kadar sürekli izlemek.</li>
	<li>Hayvan tarayıcının içinde yerleştirilir ve fizyolojik olarak kararlı olmaya devam ediyor sonra MRI taramaları başlatın. Bu çalışmada 630 mT/m bir degrade gücü ile 7 T küçük bir hayvan MRI sistemi kullanmak, ama diğer alan güçlü küçük hayvan MRG sistemlerinde kullanılabilir.</li>
	<li>MRI tarayıcı konsol monitörden "Localizer" serisi seçin ve izci görüntüler koronal, Aksiyel, oluşturmak için herhangi bir hızlı görüntü alma sırası, Örneğin, hızlı spin eko kullanarak tüm üç yönelimleri boyunca ve sagittal görüntüleri elde . Bunlar amacı izci görüntüleri görüntüleme uçaklar belirlemektir.</li>
	<li>Hayvanın baş ve boyun ortasına mıknatıs merkezinde olduğundan emin olun. Doğru konumuna ulaşılıncaya kadar gerekirse, hayvanın pozisyonunu ayarlayýn. Hayvan yeniden konumlandırdıysanız izci görüntüleri elde etmek için tarama tekrarlamak.</li>
	<li>"Saat uçuş (TOF) Anjiyo" serisi MRI tarayıcı konsol monitörden seçin ve ilk CCA tam anatomik yerini tespit etmek için bir 2D TOF anjiyo elde etmek. Aşağıdaki Tarama parametreleri kullanın: tekrarı zaman (TR) / echo zaman (TE) 22/4,87 ms, fiske vurmak açı = 90 °, görüş alanı (FOV) = 40 × 40 mm2, matris boyutu = 256 × 256, dilim kalınlığı uyarma (NEX) sayısı ile 0.6 mm = = 1. Not: TOF sırasının adı işportacı özgü olabilir. Kullanıcı konsol monitör bu parametreler ekleyebilirsiniz.</li>
	<li>Doygunluk band "açık" ve venöz sinyalleri önlemek için üst yerleştirilir emin olun. Not: Doygunluk grup için genellikle TOF dizisi ile geliyor. Doygunluk grup monitörde görünmüyorsa, hizmet kişi bildirin.</li>
	<li>TOF anjiyo kullanarak CCA bulmak sonra PC-MRI CCA ortasına görüntü boyutunda hedef ve öyle ki dilim kan akımı (Şekil 2a) yönüne dik orient.</li>
	<li>Solunum ve ECG çoğunluğuna net sinyal (Şekil 1b), monitör bilgisayarda gösterilen MRI sisteme bağlı ve "" "tetik modu" Mr tarayıcı konsol monitörden olmak tetikleyici modülü ayarlamak emin olun.</li>
	<li>Bilgisayardan izleme (Şekil 1b) PC-MRI tarama işlemini başlatmadan önce hayvanın fizyolojik yanıt istikrarlı olduğunu onaylayın. Perdeleme seçimleri "Tarih" monitör bilgisayar ve konsol monitör MRI inceden inceye gözden geçirmek içinde olduğundan emin olun. Not: Bu çalışmada kullanılan sistem izleme Fizyoloji işportacı tarafından sağlanır. En hayvan tarayıcılar için sağlanan ve işportacı özgü benzer Fizyoloji izleme sistemleri vardır.</li>
	<li>PC-MRI dizisi dizi MRI tarayıcı konsol monitörden seçin ve aşağıdaki parametreleri kullanarak geçişli PC-MRI taramaları gerçekleştirmek: TR/TE=15.55/4.51 ms (minimum TR ve TE), fiske vurmak açı 30 ° FOV = 40 × 40 mm2, matris boyutu = 192 × 192, dilim = kalınlığı 2 mm, (VENC) kodlama hızı = 120 cm/s =, = NEX ile 8. Tek yönlü VENC uçak aracılığıyla yönde kazanılır. Not: Tarama zamanı yaklaşık 8,5 min, ama gerçek tarama zamanı nedeniyle kardiyak döngüleri varyasyon hayvanlar arasında biraz farklı olabilir.</li>
	<li>CCA, başka bir konuma gibi çatallanma 4' değiştirilecek bölgedir faiz (ROI) 2.6-2,9 resim alma, yineleyin.</li>
	<li>Hayvan tarayıcıdan çıkarın ve tarama tamamlandığında onun kurtarma kafes dönmek.</li>
	<li>Hayvan vücut ısısını korumak için Isıtma lambası ile sıcak. Lamba en az 15 cm aşırı ısınmayı önlemek için hayvan uzakta tutmak.</li>
	<li>Ne zaman hayvan taşımak başlar ve bir yanıt bir kuyruk veya ayak çimdik olarak sergileyen, Isıtma lambası dön.</li>
</ol>3. veri işleme
<ol><li>MRG veri Digital Imaging and Communications Tıp (DICOM) biçimi veya diğer bir işportacı özgü biçimde kaydedin. İki tür ile Cine seriyi oluşturmak: bir büyüklük görüntüyü (anatomi) ve faz görüntü (Şekil 2b). Not: bazı tarayıcılar büyüklüğü görüntü × faz veya karmaşık farkı (farklı degradeler hız kodlama ile iki satın almalar arasında karmaşık çıkarma) olabilir, görüntü üçüncü türü oluşturulur. Üçüncü resim satıcı bağımlıdır.</li>
	<li>Görüntü verileri önceden işlemek. Gizli faz hız harita içine görüntü ve faz-ofset hata 5düzeltin. Not: Faz görüntü sinyal şiddeti gerçek hız değerleri yerine rasgele bir Bay birimi var, ama Bay sinyal şiddeti hız için doğrusal olarak orantılıdır. Faz görüntüden yüksek MRI sinyal genellikle VENC değeri olarak atanır ve minimum sinyal VENC ters değeri atanır. Matlab komut dosyası örneği için tamamlayıcı kod dosyasına 1 bakın veÇalıştır"düğmesine basın.</li>
	<li>ROI dikkatle CCA sınırını izleyerek betimlemek. Arter dilate ve çeşitli kardiyak aşamalarında oluşturmak gibi her zaman dilimi için ROIs betimlemek. Kan akımı arter yatırım getirisi, yani, hız × alan üzerinde entegre ederek hesaplayın. Her arter sonuçlandı kan akışının mL/s biriminde yapıldı. Matlab komut dosyası örneği için tamamlayıcı kod dosyasına 2 bakın veÇalıştır"düğmesine basın.</li>
</ol>

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İfşa etmek bir şey yoktur.

PC-MRI kan akımı non-invaziv ve boyuna değerlendirilmesi için kapsamlı bir yaklaşım olacaktır. Biz PC-Mr sıçan CCA'ı gerçekleştirmek için bir protokol mevcut. Bu yordam herhangi bir hayvan MRI tarayıcı gerçekleştirmek kolay ve iyi tekrarlanabilirlik gösterir.
PC-Mr tekniği insan 10,11 hem de hayvan çalışmaları 4,12artan popülerlik kazanmıştır. Bu ça...

Manyetik rezonans görüntüleme (MRG) iç vücut yapıları ve Fizyoloji ayrıntılı bilgiler sağlar ve giderek preklinik hayvan çalışmaları ve klinik tanı için kullanılıyor çok yönlü bir yaklaşımdır. Hayvan modelleri çok önemli klinik dolaylı 1daha iyi anlamak için önemlidir. Hayvan modelleri oldukça anestezi gereksinimleri ve fizyolojik parametreler ile ilgili olarak insanlardan farklı olarak, MRI yordamlar kadar hayvanlar için duruma getirilmesi önem varsayar.
Faz kontrast MRI (PC-MRI) kan akımı gibi akışı ile ilgili parametreleri ölçmek için akan spin hızı kullanır MRI özel bir türüdür. PC-MRI ile hayvan modellerini kullanarak ana arterlerde akışı desen eşleme, kardiyovasküler patolojileri 2ışık yardımcı olur. Ayrıca, PC-MRI non-invaziv kan akımı patofizyolojik koşulları 3doğal değişiklikler izleyebilirsiniz. Bu gözlemler PC-MRI insan kalp-damar hastalıkları hayvan modellerinde kullanılan değerli bir yaklaşım olduğunu göstermektedir.
Bu raporda, miktar kan akımı sıçan ortak karotid arter (CCA) için bir yöntem açıklanmaktadır. Baş ve boyun oksijenli kan ile iki CCAs vermeniz ve karotid arter hastalığı inme önemli bir nedenidir. Bu nedenle, CCA içinde erken patoloji tespit çok önemli. Bu yordamı yaklaşık olarak 15 dk süresince ve potansiyel olarak hemodinami değişikliği, böyle ateroskleroz veya kontur ile koşulları uygulanabilir.

<table><tbody><tr><td>7T small animal MRI system</td><td>Bruker</td><td></td><td></td></tr><tr><td>Isoflurane&amp;nbsp;</td><td>Baxter</td><td>1001936040</td><td>anesthetic</td></tr><tr><td>ECG lead&amp;nbsp;</td><td>3M</td><td>2269T</td><td></td></tr><tr><td>Matlab</td><td>MathWorks</td><td></td><td>sofeware for image processing</td></tr><tr><td>Monitoring and gating system</td><td>SA instruments, Inc</td><td>Model 1030</td><td></td></tr></tbody></table>

phase contrast magnetic resonance imaging in the rat common carotid artery

Faz kontrast manyetik rezonans görüntüleme (PC-MRI) kan akımı gibi akışı ile ilgili parametreleri ölçmek invaziv olmayan bir yaklaşımdır. Önceki çalışmalar anormal kan akımı sistemik vasküler riski ile ilişkili olabilir göstermiştir. Böylece, PC-MRI ilgili klinik araştırmalar için kardiyovasküler hastalıkların hayvan modellerden alınan verileri tercümesi kolaylaştırabilir. Bu raporda, biz ortak karotid arter (CCA) kan akımını ölçmek için cine-gated PC-MRI kullanarak fareler açıklayınız ve ilgili analiz yöntemleri tartışmak. Bu yordam bir imzalat, canlı hayvan gerçekleştirilebilir ve ötenazi işlemden sonra gerektirmez. Önerilen tarama parametreleri için kan akımı, sonuç mükemmel tekrarlanabilirlik gösteren tekrarlanabilir ölçümler verim. Bu makalede açıklanan PC-MRI yordam farmakolojik test, patofizyolojik değerlendirme ve serebral hemodinami değerlendirme için kullanılabilir.

Doğru dilim geometri PC-MRI deney başarısı sağlamak için çok önemli. Uçak doğru görüntü konumlandırma bir "yuvarlak" arter şekli (Şekil 3a) görüntüler ve arter ile daha az dik olduğunda bükülme, yani, arttıkça elde edilen arter geometri oval, kısmi hacmin daha büyük lider olur etkileri (Şekil 3b). Şiddetli kısmi ses efektleri kan akışı 6,<sup class="xref...

Watch this Scientific Journal Video about Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery at JoVE.com

Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery

Bu yordamı genel amacı fare ortak karotid arter kan akışında noninvaziv faz kontrast manyetik rezonans görüntüleme kullanarak ölçmek etmektir.

Faz kontrast manyetik rezonans görüntüleme sıçan ortak karotis arter

Phase contrast magnetic resonance imaging (PC-MRI) is a noninvasive approach that can quantify flow-related parameters such as blood flow. Previous ...

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Medicine

9.4K Görüntüleme.  Chang Gung Memorial Hospital. Bu yordamı genel amacı fare ortak karotid arter kan akışında noninvaziv faz kontrast manyetik rezonans görüntüleme kullanarak ölçmek etmektir.

Video: Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery

Focal Cerebral Ischemia Model by Endovascular Suture Occlusion of the Middle Cerebral Artery in the Rat

Stroke is the leading cause of disability and the third leading cause of death in adults worldwide1. In human stroke, there exists a highly variable clinical state; in the development of animal models of focal ischemia, however, achieving reproducibility of experimentally induced infarct volume is essential. The rat is a widely used animal model for stroke due to its relatively low animal husbandry costs and to the similarity of its cranial circulation to that of humans2,3. In humans, the middle cerebral artery (MCA) is most commonly affected in stroke syndromes and multiple methods of MCA occlusion (MCAO) have been described to mimic this clinical syndrome in animal models. Because recanalization commonly occurs following an acute stroke in the human, reperfusion after a period of occlusion has been included in many of these models. In this video, we demonstrate the transient endovascular suture MCAO model in the spontaneously hypertensive rat (SHR). A filament with a silicon tip coating is placed intraluminally at the MCA origin for 60 minutes, followed by reperfusion. Note that the optimal occlusion period may vary in other rat strains, such as Wistar or Sprague-Dawley. Several behavioral indicators of stroke in the rat are shown. Focal ischemia is confirmed using T2-weighted magnetic resonance images and by staining brain sections with 2,3,5-triphenyltetrazolium chloride (TTC) 24 hours after MCAO.

Surgical induction of ischemic brain damage in the rat is a widely used model for stroke research. Here we demonstrate the induction of focal cerebral ischemia by occlusion of the middle cerebral artery. Visualization of the resulting infarct by histological staining and magnetic resonance imaging is also shown.

Endovasküler Dikiş Rat Orta Serebral Arter Tıkanıklığı Fokal Serebral İskemi Model

Stroke is the leading cause of disability and the third leading cause of death in adults worldwide1. In human stroke, there exists a highly variable ...

Nörobilim

Optimized System for Cerebral Perfusion Monitoring in the Rat Stroke Model of Intraluminal Middle Cerebral Artery Occlusion

The translational potential of pre-clinical stroke research depends on the accuracy of experimental modeling. Cerebral perfusion monitoring in animal models of acute ischemic stroke allows to confirm successful arterial occlusion and exclude subarachnoid hemorrhage. Cerebral perfusion monitoring can also be used to study intracranial collateral circulation, which is emerging as a powerful determinant of stroke outcome and a possible therapeutic target. Despite a recognized role of Laser Doppler perfusion monitoring as part of the current guidelines for experimental cerebral ischemia, a number of technical difficulties exist that limit its widespread use. One of the major issues is obtaining a secure and prolonged attachment of a deep-penetration Laser Doppler probe to the animal skull. In this video, we show our optimized system for cerebral perfusion monitoring during transient middle cerebral artery occlusion by intraluminal filament in the rat. We developed in-house a simple method to obtain a custom made holder for twin-fibre (deep-penetration) Laser Doppler probes, which allow multi-site monitoring if needed. A continuous and prolonged monitoring of cerebral perfusion could easily be obtained over the intact skull.

Cerebral perfusion monitoring has been demonstrated to improve accuracy in ischemic stroke models. Technical difficulties often limit the use of this essential tool for cerebrovascular research. In this video, an optimized system is shown to obtain a single or multi-site hemodynamic monitoring during intraluminal middle cerebral artery occlusion in rats.

Intraluminar Orta Serebral Arter Tıkanıklığı ve Sıçan Strok Model Serebral Perfüzyon İzleme için Optimize Sistemi

The translational potential of pre-clinical stroke research depends on the accuracy of experimental modeling. Cerebral perfusion monitoring in animal ...

Tıp

Diffusion Imaging in the Rat Cervical Spinal Cord

Magnetic resonance imaging (MRI) is the state of the art approach for assessing the status of the spinal cord noninvasively, and can be used as a diagnostic and prognostic tool in cases of disease or injury. Diffusion weighted imaging (DWI), is sensitive to the thermal motion of water molecules and allows for inferences of tissue microstructure. This report describes a protocol to acquire and analyze DWI of the rat cervical spinal cord on a small-bore animal system. It demonstrates an imaging setup for the live anesthetized animal and recommends a DWI acquisition protocol for high-quality imaging, which includes stabilization of the cord and control of respiratory motion. Measurements with diffusion weighting along different directions and magnitudes (b-values) are used. Finally, several mathematical models of the resulting signal are used to derive maps of the diffusion processes within the spinal cord tissue that provide insight into the normal cord and can be used to monitor injury or disease processes noninvasively.

The goal of this protocol is to obtain high-quality diffusion weighted magnetic resonance imaging (DWI) of the rat spinal cord for noninvasive characterization of tissue microstructure. This protocol describes optimizations of the MRI sequence, radiofrequency coil, and analysis methods to enable DWI images free from artifacts.

Sıçan Servikal Spinal Kord difüzyon Görüntüleme

Magnetic resonance imaging (MRI) is the state of the art approach for assessing the status of the spinal cord noninvasively, and can be used as a ...

Simultaneous PET/MRI Imaging During Mouse Cerebral Hypoxia-ischemia

Dynamic changes in tissue water diffusion and glucose metabolism occur during and after hypoxia in cerebral hypoxia-ischemia reflecting a bioenergetics disturbance in affected cells. Diffusion weighted magnetic resonance imaging (MRI) identifies regions that are damaged, potentially irreversibly, by hypoxia-ischemia. Alterations in glucose utilization in the affected tissue may be detectable by positron emission tomography (PET) imaging of 2-deoxy-2-(18F)fluoro-&#7429;-glucose ([18F]FDG) uptake. Due to the rapid and variable nature of injury in this animal model, acquisition of both modes of data must be performed simultaneously in order to meaningfully correlate PET and MRI data. In addition, inter-animal variability in the hypoxic-ischemic injury due to vascular differences limits the ability to analyze multi-modal data and observe changes to a group-wise approach if data is not acquired simultaneously in individual subjects. The method presented here allows one to acquire both diffusion-weighted MRI and [18F]FDG uptake data in the same animal before, during, and after the hypoxic challenge in order to interrogate immediate physiological changes.

The method presented here uses simultaneous positron emission tomography and magnetic resonance imaging. In the cerebral hypoxia-ischemia model, dynamic changes in diffusion and glucose metabolism occur during and after injury. The evolving and irreproducible damage in this model necessitates simultaneous acquisition if meaningful multi-modal imaging data are to be acquired.

Fare Serebral Hipoksi-iskemi sırasında Eşzamanlı PET / MR Görüntüleme

Dynamic changes in tissue water diffusion and glucose metabolism occur during and after hypoxia in cerebral hypoxia-ischemia reflecting a bioenergetics ...

A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia

MRI provides a sensitive and specific imaging tool to detect acute ischemic stroke by means of a reduced diffusion coefficient of brain water. In a rat model of ischemic stroke, differences in quantitative T1 and T2 MRI relaxation times (qT1 and qT2) between the ischemic lesion (delineated by low diffusion) and the contralateral non-ischemic hemisphere increase with time from stroke onset. The time dependency of MRI relaxation time differences is heuristically described by a linear function and thus provides a simple estimate of stroke onset time. Additionally, the volumes of abnormal qT1 and qT2 within the ischemic lesion increase linearly with time providing a complementary method for stroke timing. A (semi)automated computer routine based on the quantified diffusion coefficient is presented to delineate acute ischemic stroke tissue in rat ischemia. This routine also determines hemispheric differences in qT1 and qT2 relaxation times and the location and volume of abnormal qT1 and qT2 voxels within the lesion. Uncertainties associated with onset time estimates of qT1 and qT2 MRI data vary from &plusmn; 25 min to &plusmn; 47 min for the first 5 hours of stroke. The most accurate onset time estimates can be obtained by quantifying the volume of overlapping abnormal qT1 and qT2 lesion volumes, termed 'Voverlap' (&plusmn; 25 min) or by quantifying hemispheric differences in qT2 relaxation times only (&plusmn; 28 min). Overall, qT2 derived parameters outperform those from qT1. The current MRI protocol is tested in the hyperacute phase of a permanent focal ischemia model, which may not be applicable to transient focal brain ischemia.

A protocol for stroke onset time estimation in a rat model of stroke exploiting quantitative magnetic resonance imaging (qMRI) parameters is described. The procedure exploits diffusion MRI for delineation of the acute stroke lesion and quantitative T1 and T2 (qT1 and qT2) relaxation times for timing of stroke.

Manyetik rezonans görüntüleme protokolü için kontur başlangıçlı süresi tahmini olarak kalıcı serebral iskemi

MRI provides a sensitive and specific imaging tool to detect acute ischemic stroke by means of a reduced diffusion coefficient of brain water. In a rat ...

Quantitative MRI of Endothelial Permeability and (Dys)function in Atherosclerosis

Cardiovascular diseases are the leading causes of death worldwide. A permeable/leaky and dysfunctional endothelium is considered the earliest marker of vascular damage and thought to drive atherosclerosis. A method to identify these changes in vivo would be desirable in the clinic. Magnetic resonance imaging (MRI)-based tools and other technologies have enabled a profound understanding of the role of the endothelium in cardiovascular diseases and risk in vivo. There is, however, a need for reproducible and simple approaches for extracting quantifiable data reflective of endothelial damage from a single imaging study. A non-invasive, easy-to-implement, and quantitative MRI workflow was developed to acquire and analyze images that allow the quantification of two imaging biomarkers of arterial endothelial damage (leakiness/permeability and dysfunction). Here, the protocol describes the application of this method in the brachiocephalic artery of atherosclerotic ApoE-/- mice using a clinical MRI scanner. First, late gadolinium enhancement (LGE) and Modified Look-Locker Inversion Recovery (MOLLI) T1 mapping protocols to quantify endothelial leakage using an albumin-binding probe are described. Second, anatomic, and quantitative blood flow sequences to measure endothelial dysfunction, in response to acetylcholine are described. Importantly, the method outlined here allows the acquisition of high-spatial-resolution 3D images with large volumetric coverage enabling accurate segmentation of vessel wall structures to improve inter- and intra-observer variability and to increase reliability and reproducibility. Additionally, it provides quantitative data without the need for high-temporal resolution for complex kinetic modeling, making it model-independent and even allowing for imaging of highly mobile vessels (coronary arteries). Therefore, the approach simplifies and expedites data analysis. Finally, this method can be implemented on different scanners, can be extended to image different arterial beds, and is clinically applicable for use in humans. This method could be used to diagnose and treat patients with atherosclerosis by adopting a precision-medicine approach.

Quantitative MRI of Endothelial Permeability and Dysfunction in Atherosclerosis

We have developed an accurate, non-invasive, and easy-to-use method to quantify endothelial permeability and dysfunction in the arteries using Magnetic Resonance Imaging (MRI), named qMETRIC. This technique enables assessing vascular damage and cardiovascular risk associated with atherosclerosis in preclinical models and humans.

Cardiovascular diseases are the leading causes of death worldwide. A permeable/leaky and dysfunctional endothelium is considered the earliest marker of ...

Biyomühendislik

Ferric Chloride-induced Canine Carotid Artery Thrombosis: A Large Animal Model of Vascular Injury

Occlusive arterial thrombosis leading to cerebral ischemic stroke and myocardial infarction contributes to ~13 million deaths every year globally. Here, we have translated a vascular injury model from a small animal into a large animal (canine), with slight modifications that can be used for pre-clinical screening of prophylactic and thrombolytic agents. In addition to the surgical methods, the modified protocol describes the step-by-step methods to assess carotid artery canalization by angiography, detailed instructions to process both the brain and carotid artery for histological analysis to verify carotid canalization and cerebral hemorrhage, and specific parameters to complete an assessment of downstream thromboembolic events by utilizing magnetic resonance imaging (MRI). In addition, specific procedural changes from the previously well-established small animal model necessary to translate into a large animal (canine) vascular injury are discussed.

Here, we present the modifications necessary to a well characterized and commonly used small animal ferric chloride-induced (FeCl3) carotid artery injury model for use in a large animal vascular injury model. The resulting model can be utilized for pre-clinical trial assessment of both prophylactic and thrombolytic pharmacological and mechanical interventions.

Ferrik klorid kaynaklı köpek karotid arter trombozu: Bir büyük hayvan modeli vasküler yaralanma

Occlusive arterial thrombosis leading to cerebral ischemic stroke and myocardial infarction contributes to ~13 million deaths every year globally. Here, ...

Middle Cerebral Artery Occlusion Allowing Reperfusion via Common Carotid Artery Repair in Mice

The ischemic stroke is a major cause of adult long-term disability and death worldwide. The current treatments available are limited, with only tissue plasminogen activator (tPA) as an approved drug treatment to target ischemic strokes. Current research in the field of ischemic stroke focuses on better understanding the pathophysiology of stroke, to develop and investigate novel pharmaceutical targets. Reliable experimental stroke models are crucial for the progression of potential treatments. The middle cerebral artery occlusion (MCAO) model is clinically relevant and the most frequently used surgical model of ischemic stroke in rodents. However, the outcomes of this model, such as lesion volume, are associated with high levels of variability, particularly in mice. The alternative MCAO model described here allows the reperfusion of the common carotid artery (CCA) and the increased perfusion of the middle cerebral artery (MCA) territory, using a tissue pad with fibrinogen-based sealant to repair the vessel, and the improved welfare of the mice by avoiding external carotid artery (ECA) ligation. This reduces the reliance on the Circle of Willis, which is known to be highly anatomically variable in mice. Representative data show that using this alternative surgical approach decreases the variability in lesion volumes between the traditional MCAO approach and the alternative approach described here.

Intraluminal filament occlusion of the middle cerebral artery is the most frequently used in vivo model of experimental stroke in rodents. An alternative surgical approach to allow common carotid artery repair is performed here, which allows the reperfusion of the common carotid artery and a full reperfusion to the middle cerebral artery territory.

Orta serebral arter tıkanıklığı ortak karotid arter onarım ile reperfüzyon farelerde izin

The ischemic stroke is a major cause of adult long-term disability and death worldwide. The current treatments available are limited, with only tissue ...

Cardiac Magnetic Resonance Imaging

Source: Frederick W. Damen and <a href="https://www.jove.com/author/Craig+J._Goergen">Craig J. Goergen</a>, Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
In this video, high field, small-bore magnetic resonance imaging (MRI) with physiological monitoring is demonstrated to acquire gated cine loops of the murine cardiovascular system. This procedure provides a basis for assessing left-ventricular function, visualizing vascular networks, and quantifying motion of organs due to respiration. Comparable small animal cardiovascular imaging modalities include high-frequency ultrasound and micro-computed tomography (CT); however, each modality is associated with trade-offs that should be considered. While ultrasound does provide high spatial and temporal resolution, imaging artifacts are common. For example, dense tissue (i.e., the sternum and ribs) can limit imaging penetration depth, and hyperechoic signal at the interface between gas and liquid (i.e., pleura surrounding the lungs) can blur contrast in nearby tissue. Micro-CT in contrast does not suffer from as many in-plane artifacts, but does have lower temporal resolution and limited soft-tissue contrast. Furthermore, micro-CT uses X-ray radiation and often requires the use of contrast agents to visualize vasculature, both of which are known to cause side effects at high doses including radiation damage&#160; and renal injury. Cardiovascular MRI provides a nice compromise between these techniques by negating the need for ionizing radiation and providing the user with the ability to image without contrast agents (although contrast agents are often used for MRI).
This data was acquired with a triggering Fast Low Angle SHot (FLASH) MRI sequence that was gated off of the R-peaks in the cardiac cycle and expiratory plateaus in respiration. These physiological events were monitored through subcutaneous electrodes and a pressure-sensitive pillow that was secured against the abdomen. To ensure the mouse was properly warmed, a rectal temperature probe was inserted and used to control the output of a MRI-safe heating fan. Once the animal was inserted into the bore of the MRI scanner and navigation sequences were run to confirm positioning, the gated FLASH imaging planes were prescribed and data acquired. Overall, high field MRI is a powerful research tool that can provide soft tissue contrast for the study of small animal disease models.

Cardiac MRI: Principle and Imaging

Source: Frederick W. Damen and Craig J. Goergen, Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
In this video, high ...

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 Phase Contrast Magnetic Resonance Imaging to Assess Blood Flow in the Arteries of a Rat

<a href='https://app.jove.com/v/57304/phase-contrast-magnetic-resonance-imaging-rat-common-carotid'>Source: Chiu, S., et al. Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery. J. Vis. Exp. (2018).</a>This video demonstrates phase contrast magnetic resonance imaging (PC-MRI) to measure blood flow in the common carotid artery of a rat. After securing an anesthetized rat on the MRI bed and ensuring stable physiological parameters, the common carotid artery is scanned to capture images at defined intervals. Blood flow is then computed from these images to evaluate changes throughout the cardiac cycle.

Source: Chiu, S., et al. Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery. J. Vis. Exp. (2018).This video demonstrates phase ...