Noninvasive Vascular Imaging Research Articles

Role of Imaging in Acute Ischemic Stroke

Rapid multimodal imaging is essential in the workup and management of acute ischemic stroke. Early parenchymal findings on noncontrast computed tomography or standard magnetic resonance imaging are used to triage patients for intravenous thrombolysis and to provide insight on prognosis. In the wake of recent endovascular stroke trials, advanced techniques including perfusion imaging and noninvasive vascular imaging are becoming important tools to guide potential endovascular treatment or expand therapy windows. Advanced imaging is also important in pediatric ischemic stroke which requires a slightly different workflow and treatment approach. Here, we will discuss key imaging findings in acute ischemic stroke, as well as the present and future of neuroimaging in light of recent and ongoing clinical trials.

Quantitative biometry of zebrafish retinal vasculature using optical coherence tomographic angiography.

The zebrafish is a robust model for studying human ophthalmic function and disease because of its fecundity, life-cycle, and similarities between its retinal structure and the human retina. Here, we demonstrate longitudinal in vivo imaging of retinal structure using optical coherence tomography (OCT) and noninvasive retinal vascular perfusion imaging using OCT angiography (OCT-A) in zebrafish. In addition, we present methods for retinal vascular segmentation and biometry to quantify vessel branch length, curvature, and angle. We further motivate retinal vascular biometry as a novel method for noninvasive zebrafish identification and demonstrated 99.9% accuracy for uniquely identifying eyes from a set of 200 longitudinal OCT/OCT-A volumes. The described methods enable the quantitative analysis of the vascular changes in zebrafish models of ophthalmic diseases and may broadly benefit large-scale zebrafish studies.

Mechanical thrombectomy: Determining the proportion of eligible acute ischemic stroke patients in the cohort of single academic stroke center

Background and purposeMechanical thrombectomy (MT) is now well-established treatment method for selected patients with acute ischemic stroke (AIS) and efforts are being made to incorporate it into the systems of stroke care. Our objective is to assess the number of AIS individuals eligible for MT in the cohort of single academic stroke center. MethodsWe retrospectively reviewed initial non-invasive vascular imaging data of AIS patients presenting within 5h of symptom onset for the presence of large vessel occlusion (LVO) over 2-year period (2015–2016). Among subjects confirmed with LVO: time-to-presentation, premorbid functional and on-admission neurological state, site of occlusion and initial imaging data were further assessed. Two sets of criteria based on recent trials and recommendations were used to determine MT eligibility. The onset-to-evaluation time limit was set to 5h allowing ≤60min procedure initiation delay. Results895 patients with the final diagnosis of AIS were admitted to our stroke center as the initial treatment facility. 246 (27.5%) presented within 5h of symptom onset and had non-invasive imaging performed. Among those 102 (41.5%) had causative LVO. The number of ≤5h presenting patients eligible for MT was 51 (20.7%) when applying restrictive or 80 (32.5%) with more permissive criteria. ConclusionAmong AIS patients, in whom onset-to-arrival time allowed to initiate the endovascular procedure within 6h of symptom duration, 21% were eligible for MT treatment according to more and 33% to less restrictive criteria. It accounts for about 6% and 9% of all AIS cases, respectively.

In-vivo imaging of the microvasculature of the soft tissue margins of osteonecrotic jaw lesions.

Introduction Given the increasing incidence of medication-related jaw osteonecrosis, and recognition of the mucosal blood supply's importance, we have developed a non-invasive Real Time Optical Vascular Imaging (RTOVI) instrument. Imaging the red blood cells within the sub-mucosal capillary networks demonstrates the microcirculatory anatomy. We report a small trial, demonstrating the technique's viability, examining mucosal microcirculatory changes adjacent to osteonecrotic lesions.Aims Imaging the microvasculature of soft tissue margins of patients' exposed necrotic bone lesions in situ was intended to provide unique observational as well as quantitative data, using an image analysis routine, based on ImageJ software. Our interest was to evaluate whether this could offer valuable information for complex wound margin management.Methods Four osteoradionecrosis and four medication-related osteonecrosis patients (M:F 1:1 mean 68.25 years) were enrolled under the NRES Ethics 11/LON/0354 and KCL Research Ethics Committee (REC) BDM/14/15-14 approvals. Microvascular images from mucosal margins of exposed mandibular osteonecrosis lesions were compared with equivalent images from both uninvolved contralateral mucosa and similar mucosal sites in four healthy subjects.Results We demonstrated narrow hypo-vascularised oedematous lesion margins surrounded by a concentric inflammatory band and normal mucosa beyond. Parameters reporting individual capillary shape, via mean percentage of occupancy per capillary per field of view and capillary loop aspect ratio, differed significantly between groups (ANOVA, p = 0.0002 and p = 0.04 respectively). Values reporting capillary number and area showed expected changes but did not reach statistical significance.Conclusion This pilot study demonstrated the feasibility of mucosal microvascular imaging in assessing the microvascular changes found in the soft tissues at the margins of osteonecrotic lesions, with potential to inform therapeutic interventions and clinical decisions to continue or modify regime strategies at the earliest opportunity. Given the increasing incidence of medication-related jaw osteonecrosis, and the recognition of the importance of mucosal blood supply, we developed a non-invasive instrument demonstrating microcirculation anatomy by imaging transiting red blood cells.

Large arterial occlusive strokes as a medical emergency: need to accurately predict clot location.

Endovascular treatment for acute ischemic stroke with a large intracranial occlusion was recently shown to be effective. Timely knowledge of the presence, site, and extent of arterial occlusions in the ischemic territory has the potential to influence patient selection for endovascular treatment. We aimed to find predictors of large vessel occlusive strokes, on the basis of available demographic, clinical, radiological, and laboratory data in the emergency setting. Patients enrolled in ASTRAL registry with acute ischemic stroke and computed tomography (CT)-angiography within 12 h of stroke onset were selected and categorized according to occlusion site. Easily accessible variables were used in a multivariate analysis. Of 1645 patients enrolled, a significant proportion (46.2%) had a large vessel occlusion in the ischemic territory. The main clinical predictors of any arterial occlusion were in-hospital stroke [odd ratios (OR) 2.1, 95% confidence interval 1.4-3.1], higher initial National Institute of Health Stroke Scale (OR 1.1, 1.1-1.2), presence of visual field defects (OR 1.9, 1.3-2.6), dysarthria (OR 1.4, 1.0-1.9), or hemineglect (OR 2.0, 1.4-2.8) at admission and atrial fibrillation (OR 1.7, 1.2-2.3). Further, the following radiological predictors were identified: time-to-imaging (OR 0.9, 0.9-1.0), early ischemic changes (OR 2.3, 1.7-3.2), and silent lesions on CT (OR 0.7, 0.5-1.0). The area under curve for this analysis was 0.85. Looking at different occlusion sites, National Institute of Health Stroke Scale and early ischemic changes on CT were independent predictors in all subgroups. Neurological deficits, stroke risk factors, and CT findings accurately identify acute ischemic stroke patients at risk of symptomatic vessel occlusion. Predicting the presence of these occlusions may impact emergency stroke care in regions with limited access to noninvasive vascular imaging.

Noninvasive Vascular Modulography Method for Imaging the Local Elasticity of Atherosclerotic Plaques: Simulation and In Vitro Vessel Phantom Study

Mechanical and morphological characterization of atherosclerotic lesions in carotid arteries remains an essential step for the evaluation of rupture prone plaques and the prevention of strokes. In this paper, we propose a noninvasive vascular imaging modulography (NIV-iMod) method, which is capable of reconstructing a heterogeneous Young's modulus distribution of a carotid plaque from the Von Mises strain elastogram. Elastograms were computed with noninvasive ultrasound images using the Lagrangian speckle model estimator and a dynamic segmentation-optimization procedure to highlight mechanical heterogeneities. This methodology, based on continuum mechanics, was validated in silico with finite-element model strain fields and ultrasound simulations, and in vitro with polyvinyl alcohol cryogel phantoms based on magnetic resonance imaging geometries of carotid plaques. In silico, our results show that the NiV-iMod method: 1) successfully detected and quantified necrotic core inclusions with high positive predictive value (PPV) and sensitivity value (SV) of 81±10% and 91±6%; 2) quantified Young's moduli of necrotic cores, fibrous tissues, and calcium inclusions with mean values of 32±23, 515±30, and 3160±218 kPa (ground true values are 10, 600, and 5000 kPa); and 3) overestimated the cap thickness by . In vitro, the PPV and SV for detecting soft inclusions were 60±21% and 88±9%, and Young's modulus mean values of mimicking lipid, fibrosis, and calcium were 34±19, 193±14, and 649±118 kPa (ground true values are 25±3, 182±21, and 757±87 kPa).

Increasing Role of Dual-Energy CT in Noninvasive Vascular Imaging

Increasing Role of Dual-Energy CT in Noninvasive Vascular Imaging

Headache, TIA and subarachnoid haemorrhage: dissecting an unusual cause for stroke-like symptoms

We present a case of supraclinoid internal carotid artery dissection. Eleven months prior, the patient developed isolated periorbital pain and was diagnosed with giant-cell arteritis with iritis. The patient experienced...

Re-evaluating the Appropriateness of Non-invasive Arterial Vascular Imaging and Diagnostic Modalities.

Imaging modalities to detect and diagnose vascular disease have become increasingly popular in recent years, owing in large part to their availability and accessibility. The American College of Cardiology Foundation published a two-part Appropriate Use Criteria (AUC) guidance document for both peripheral vascular imaging and physiologic testing several years ago. In the years since their publication, a number of important studies have challenged previously held beliefs about appropriateness of vascular diagnostic testing. To address the ever-changing landscape, we offer a review of the current appropriate use guidelines for arterial vascular diagnostic procedures and relevant major studies published in the interim. We aim to provide a comprehensive review of appropriate arterial vascular diagnostic imaging testing for the cardiovascular clinician.

Statistical Permutation-based Artery Mapping (SPAM): a novel approach to evaluate imaging signals in the vessel wall

BackgroundCardiovascular diseases are the leading cause of death worldwide. A prominent cause of cardiovascular events is atherosclerosis, a chronic inflammation of the arterial wall that leads to the formation of so called atherosclerotic plaques. There is a strong clinical need to develop new, non-invasive vascular imaging techniques in order to identify high-risk plaques, which might escape detection using conventional methods based on the assessment of the luminal narrowing. In this context, molecular imaging strategies based on fluorescent tracers and fluorescence reflectance imaging (FRI) seem well suited to assess molecular and cellular activity. However, such an analysis demands a precise and standardized analysis method, which is orientated on reproducible anatomical landmarks, ensuring to compare equivalent regions across different subjects.MethodsWe propose a novel method, Statistical Permutation-based Artery Mapping (SPAM). Our approach is especially useful for the understanding of complex and heterogeneous regional processes during the course of atherosclerosis. Our method involves three steps, which are (I) standardisation with an additional intensity normalization, (II) permutation testing, and (III) cluster-enhancement. Although permutation testing and cluster enhancement are already well-established in functional magnetic resonance imaging, to the best of our knowledge these strategies have so far not been applied in cardiovascular molecular imaging.ResultsWe tested our method using FRI images of murine aortic vessels in order to find recurring patterns in atherosclerotic plaques across multiple subjects. We demonstrate that our pixel-wise and cluster-enhanced testing approach is feasible and useful to analyse tracer distributions in FRI data sets of aortic vessels.ConclusionsWe expect our method to be a useful tool within the field of molecular imaging of atherosclerotic plaques since cluster-enhanced permutation testing is a powerful approach for finding significant differences of tracer distributions in inflamed atherosclerotic vessels.

Ultrasound imaging in the diagnosis of large vessel vasculitis.

Nowadays noninvasive vascular imaging has an important role in the diagnostic work-up of the large vessel vasculitides (LVV), most importantly giant cell arteritis (GCA) and Takayasu arteritis. Among the imaging modalities available, ultrasound (US) has several important advantages, including low costs, rapid and repetitive availability without exposure to radiation, and high spatial resolution for assessment of large and medium-sized arteries. Therefore, US can be regarded the first line imaging method in suspected LVV. In patients with suspected GCA, US can replace temporal artery biopsy in certain clinical scenarios, and the application of US early in the diagnostic work-up of suspected GCA in specialized fast track clinics has been suggested to reduce the rate of visual ischaemic complications and associated costs. In other LVV such as Takayasu arteritis and chronic periaortitis, the diagnostic accuracy in comparison to other noninvasive imaging methods has not been formally tested but can be considered to be excellent. However, quality of US is highly dependent on the operator's experience, and assessment of the thoracic aorta which is frequently involved in GCA and TA is limited. The role of US in the follow-up of LVV under treatment is unclear. In view of the promising data supporting its value on the one hand and several uncertainties and controversies on the other hand, the present review article provides a comprehensive overview on current evidence for the application of US in the diagnosis and follow up of LVV. Recent multicentre study results and emerging trends such as the application of compression sonography in the diagnosis of GCA and the use of contrast enhanced ultrasound in disease activity assessment in Takayasu arteritis are discussed.

Abstract P4-01-10: Development of photoacoustic vascular imaging system for breast cancer

Abstract Background: Tumor angiogenesis and hypoxia are associated with breast cancer growth and metastasis. Photoacoustic (PA) tomography is an optical imaging technology that visualizes distribution and oxygenation status of hemoglobin with high spatial resolution. Initially we developed a photoacoustic mammography (PAM) having a flat-shaped scanning detector that could detect breast tumors. Nevertheless, the flat-shaped detector array has the drawback of a limited view. Here we developed a novel PAM system with a hemispherical-shaped detector array (HDA), which enables us to identify microvasculatures non-invasively and allow the collection of nearly spatially isotropic three-dimensional reconstructed image of blood vessels. This non-invasive vascular imaging system may be able to characterize tumor angiogenesis and analyze the status of microcirculation. The aim of this study was to analyze the imaging findings of tumor-related vasculature in breast cancer patients. Patients and method: A PAM system with HDA has been generated in a cooperation project between Canon Inc., Japan, and Kyoto University. Twenty-two primary breast cancer patients, including 5 patients with non-invasive cancer and 17 patients with invasive cancer, diagnosed between December 2014 and December 2015 underwent the PAM imaging analysis. We also applied the breast deformation algorithm from the breast shape in a MRI image to that in a PA image in order to create a fusion image of the two modalities for the analysis. Features of peri- and intra-tumoral vasculature, and their oxygenation status were evaluated. The study protocol was approved by the institutional review board at Kyoto University Hospital (UMIN000012251). All patients provided informed consent to participate in this study. Results: The abnormal peri-tumoral vasculature was detected in 86% of all non-invasive and invasive disease cases. In invasive cancer cases, most tumor-related blood vessels were centripetally directed toward the tumor, and 93% of centripetal blood vessels appeared to be disrupted or rapidly narrowed at the tumor boundary. The centripetal blood vessel structure was frequently observed in invasive cancer compared with non-invasive cancer (61% vs 35%). PA images before and after preoperative chemotherapy were obtained in one case, where intra-tumoral blood vessels became finer after chemotherapy, reflecting normalization of intra-tumoral microcirculation induced by chemotherapy. Conclusions: A PAM system with HDA has provided a high-resolution vascular images of primary breast cancers. The morphological differences of peri-tumoral vasculature were observed between invasive disease and non-invasive disease. These results suggest the potential of PA imaging as a non-invasive tool to analyze tumor vasculature of human breast cancers and maybe be helpful for breast cancer diagnosis. (Acknowledgements) This work was partially supported by the Innovative Techno-Hub for Integrated Medical Bio-imaging Project of the Special Coordination Funds for Promoting Science and Technology from the Ministry of Education, Culture, Sports, Science, and Technology, Japan. Citation Format: Toi M, Asao Y, Takada M, Kataoka M, Endo T, Kawashima M, Yamaga I, Nakayama Y, Tokiwa M, Fakhrejahani E, Torii M, Kawaguchi-Sakita N, Kanao S, Matsumoto Y, Yagi T, Sakurai T, Togashi K, Shiina T. Development of photoacoustic vascular imaging system for breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-01-10.

Relationships between retinal arteriole anatomy and aortic geometry and function and peripheral resistance in hypertensives.

Microvascular remodeling and large artery stiffness are key determinants of cardiovascular hemodynamics and can now be studied with new non-invasive methods. Our objective was to study the relationships between retinal arteriole anatomy and aortic geometry and function and peripheral resistance (total peripheral resistance (TPR)) in hypertensives. In 80 subjects (age 52±13 years; 53% males; including 23 normotensives and 57 hypertensives, among which 29 were uncontrolled hypertensives), we used: (1) the new non-invasive RTX1 adaptive optics (AO) camera (Imagine Eyes, Orsay, France) to measure the wall-to-lumen ratio (WLR) on retinal microvasculature; (2) cardiovascular magnetic resonance (CMR) imaging to assess aortic stiffness, geometry and cardiac output; and (3) the validated SphymoCor Xcel device to measure central blood pressure (BP) and carotido-femoral pulse wave velocity (Cf-PWV). TPR was calculated as the central mean BP/cardiac output ratio. WLR and TPR were significantly higher and aortic distensibility was significantly lower in hypertensives. Aortic dilation and arch elongation were found in uncontrolled hypertensives. In the univariate analysis, WLR was positively correlated with central BP (P<0.001), TPR (P<0.001) and Cf-PWV (P<0.05), and it was negatively correlated with aortic distensibility (P=0.003); however, it was not correlated with age or cardiovascular risk factors. The multivariate analysis indicated that WLR was associated with TPR (P=0.002) independent of age, BMI, gender, antihypertensive treatments, aortic diameter and central SBP. As expected, age was the major correlate of ascending aorta distensibility and Cf-PWV. New non-invasive vascular imaging methods are complementary for the detection of the deleterious effects of aging or high BP on large and small arteries. AO examination could represent a useful tool for the study and follow-up of microvasculature anatomical changes.

Abstract TP226: Vertebral Artery Dissection is More Common Than Carotid Artery Dissection and More Difficult to Detect on Non-invasive Imaging

Background: Cervical artery dissections (CAD) are among the most common causes of stroke in young and middle-aged adults. In contrast to carotid dissections (CD) and anterior circulation ischemia, the clinical manifestations of vertebral dissections (VD) and posterior circulation ischemia are often nonspecific (e.g. dizziness and ataxia), and thus a high index of suspicion is necessary for diagnosis. Therefore, the reported incidence of VD in the medical literature is likely to be an underestimation. Methods: With IRB approval, we conducted a retrospective chart review study using the Neurology Database of Houston Methodist Neurological Institute to identify all patients diagnosed with CAD between August 2011 and March 2015. All patients presented with cerebral ischemia (TIA or stroke). The diagnosis of CAD was made by a stroke neurologist and was based on clinical presentation and appropriate vascular imaging studies. Patients with incidental CAD and those with questionable diagnosis of CAD clinically and radiographically were excluded. Over the studied period (32 months), a total of 677 TIA patients and 3230 stroke patients were admitted to our tertiary-care hospital. Results: Of 52 patients with CAD-related TIA or ischemic stroke, there were 34 patients (65.4%) with VD and 18 patients (34.6%) with CD. The average age of presentation is 47 years (range: 18 to 75 years) for VD patients and 51 years (range: 34 to 78 years) for CD patients. CAD was slightly more common in males, with 18 VD patients (52.9%) and 10 CD patients (55.5%) in our studied population were males. Out of 30 patients with VD who underwent both noninvasive vascular imaging (MRA or CTA) and cerebral angiogram, dissection was detected on noninvasive imaging in 10 patients (33.3%). On the other hand, out of 13 patients with CD who had both types of imaging modalities, dissection was detected on noninvasive testing in 8 patients (61.5%). Conclusions: VD was detected approximately twice as frequently as CD in our study. Both conditions are slightly more common in men with an average age of presentation is about 50 years. In addition, our data suggest that noninvasive testing is more likely to diagnose carotid dissection (in two-third of cases) than vertebral dissection (in one-third of cases).

Risk Factors.

Studies investigating risk factors for intracranial atherosclerosis (ICAS) have been infrequent. However, due to recent availability of non-invasive vascular imaging techniques that can assess intracranial cerebral arteries, there are a growing number of studies on risk factors for ICAS. Conventional vascular risk factors such as hypertension, diabetes, hypercholesterolemia and cigarette smoking are risk factors for ICAS. However, it remains uncertain whether there is a difference in risk factors between ICAS and extracranial atherosclerosis (ECAS). It also remains unclear why ICAS is more common in Asians and Blacks than in Caucasians. Although we reviewed available evidences on these differences, the review was limited because studies were heterogeneous in the definition of risk factors, diagnostic method, and characteristics of study subjects (hospitalized vs. community) or cerebral vessels (symptomatic vs. asymptomatic). Nevertheless, it seems that hypercholesterolemia is more closely associated with ECAS than ICAS. The difference in hypercholesterolemia prevalence is one of the main reasons for racial differences in the location of cerebral atherosclerosis. Intracranial arteries contain higher antioxidant level than extracranial arteries and may be more vulnerable to risk factors that deplete antioxidants (e.g., metabolic syndrome and diabetes mellitus). Intracranial arteries may be more vulnerable to factors associated with hemodynamic stress (e.g., advanced, salt-retaining hypertension and arterial tortuosity) because of a smaller diameter, thinner media and adventitia, and fewer elastic medial fibers than extracranial arteries. Additionally, non-atherosclerotic arterial diseases (e.g., moyamoya disease) that commonly occur in the intracranial arteries of East Asians may contaminate the reports of ICAS cases. Various genes, including RNF 213, might also explain racial differences in atherosclerotic location. Prospective, well-designed risk factor and genetic studies should be performed in a homogeneous group of patients with diverse ethnicities. These efforts are essential in the prevention of atherosclerotic diseases based on adequate knowledge of the risk factors and pathogenesis.

Emergency Imaging of Intracerebral Haemorrhage.

Spontaneous intracerebral haemorrhage (ICH) is a devastating condition with high mortality and morbidity despite advances in neurocritical care. Early deterioration is common in the first few hours after ICH onset, secondary to rapid haematoma expansion and growth. Rapid diagnosis and aggressive early management of these patients are therefore crucial. Imaging plays a key role in establishing the diagnosis and the underlying aetiology of ICH, identifying complications and predicting patients who are at high risk for haematoma expansion. In this chapter, we present an evidence-based imaging framework for the management of spontaneous ICH in the acute setting. Non-enhanced computed tomography is long established as the gold standard for ICH diagnosis but has limitations in demonstrating the underlying aetiology in cases of secondary ICH. There is now growing evidence for the ability of non-invasive angiography to establish the underlying aetiology and to predict further haematoma expansion. The presence of small enhancing foci within the haematoma on computed tomography angiography (CTA), the CTA Spot Sign, has been prospectively validated as a predictor of haematoma expansion. Early identification of patients at risk of haematoma expansion allows for the appropriate escalation of care to a neurosurgical team, admission to a neurocritical care unit, appropriate supportive therapy and targeted novel medical and surgical interventions. Catheter angiography, which remains the gold standard for identifying underlying secondary vascular lesions, should be used in selected cases. However, non-invasive vascular imaging should be considered as an important step in the diagnosis and early management of secondary ICH patients. Previous concerns related to the radiation dose, contrast-induced nephropathy and cost are addressed in this chapter. Recently, animal models have enabled the qualitative assessment of haematoma expansion, and our increased understanding of ICH may inform future trials of targeted medical and surgical therapies.

Pulse volume recording for peripheral vascular disease diagnosis in diabetes patients

Pulse volume recording for peripheral vascular disease diagnosis in diabetes patients Erik Benitez, Bauer E Sumpio Department of Surgery (Vascular), Yale University School of Medicine, New Haven, CT, USA Abstract: Peripheral arterial disease is common in patients with diabetes mellitus. It has become routine to screen for peripheral arterial disease in diabetic patients. As clinicians&#39; knowledge and understanding of the disease processes increase, the diagnosis and surveillance also rises. As an adjunct to clinical examination, pulse volume recordings are useful in assessing perfusion of patients with poorly compressible arteries. The development of this study during the early 70s helped create the concept of noninvasive vascular imaging and testing. The analysis of pressure&ndash;pulse waveforms localized the presence of high-grade lesions and delineated the extent of the disease process. Pulse volume recordings are currently extensively used with other modalities such as arterial duplex and angiography and help to establish an arterial etiology of a patient&#39;s disease process, as well as localizing the lesion, determining the prognosis, and performing surveillance after interventions. Keywords: pulse volume recordings, ankle brachial index, peripheral arterial disease, diabetes mellitus, critical limb ischemia, pulse wave contour, pressure&ndash;pulse waveforms

Real-Time Elastography Visualization and Histopathological Characterization of Rabbit Atherosclerotic Carotid Arteries

To evaluate the feasibility of non-invasive vascular real-time elastography imaging (RTE) in visualizing the composition of rabbit carotid atherosclerotic plaque as determined by histopathology, a rabbit model of accelerated carotid atherosclerosis was used. Thirty rabbits were randomly divided into two groups of 15 rabbits each. The first group was fed a cholesterol-rich diet and received balloon-induced injury the left common carotid artery endothelium, whereas the second group only received a cholesterol-rich diet. The rabbits were all examined in vivo with HITACHI non-invasive vascular real-time elastography (Hi-RTE) at baseline and 12 wk, and results from the elastography were compared with American Heart Association histologic classifications. Hi-RTE and the American Heart Association histologic classifications had good agreement, with weighted Cohen's kappa (95% confidence internal) of 0.785 (0.649–0.920). Strains of segmented plaques that were stained in different colors were statistically different (p < 0.0001). The sensitivity and specificity of elastograms for detecting a lipid core were 95.5% and 61.5%, respectively, and the area under the receiver operating characteristic curve was 0.789, with a 95% confidence interval of 0.679 to 0.876. This study is the first to indicate the feasibility of utilizing Hi-RTE in visualizing normal and atherosclerotic rabbit carotid arteries non-invasively. This affordable and reliable method can be widely applied in research of both animal and human peripheral artery atherosclerosis.

Noninvasive vascular imaging of moyamoya: Diagnosis, followup, and surgical planning

Moyamoya disease and syndrome are typically described by their imaging features on cerebral angiography, however advances in noninvasive imaging has allowed improved anatomic and physiologic characterization of this vascular abnormality. Advanced imaging complements the role of cerebral angiography, and when used appropriately can provide valuable information regarding the diagnosis, treatment planning, and surveillance in patients with moyamoya. Techniques to be aware of include computed tomography, CT-angiography, Magnetic Resonance Imaging, MR Angiography (time-of-flight and dynamic contrast enhancemed angiography), and perfusion imaging (CT perfusion, arterial spin labeling perfusion, and nuclear medicine perfusion). With an appropriate understanding and implementation of noninvasive techniques, this disease process can be better understood allowing for improved patient management.

Proposed methodology and classification of Infarct in New Territory (INT) after endovascular stroke treatment.

While the overall complication rates for endovascular treatment for acute stroke has been extremely low in recent trials, it is important to separate out and accurately document complications. One of these complications that is usually related to the endovascular intervention is Infarct in New Territory (INT). We propose a standardized methodology for documenting INT after the procedure. This new classification takes into account variations in vascular anatomy and location of the occlusion. In addition, given that after the recent trials, vascular imaging (eg, CT angiography (CTA)) is now the standard of care in the work up of acute ischemic stroke, this classification utilizes the information on the pre-procedure non-invasive vascular imaging, the angiography images from end of procedure and the location of lesions on the follow-up scan.