Faculty Bibliography

We report a case of temporary Solitaire FR stent (Covidien, Mansfield, MA, USA) scaffolding to reduce coil herniation during embolization of a large neck anterior communicating artery aneurysm. In contrast to classic stent-assisted coiling, the fully retrievable stent is recaptured prior to detachment of the last coil. The presented technical nuance hence does not require institution of prolonged antiplatelet coverage. But the door is left open for coil-repositioning in case of coil basket instability. Permanent stent redeployment remains a fall-back option if critical hardware conflict occurs. In comparison to classic balloon remodeling, the presented method may offer easier distal access, particularly in tortuous arterial anatomy. Temporary occlusion of the parent artery, side branches, and perforators is also avoided. Given its specific potential advantages, temporary stent scaffolding using the fully retrievable Solitaire FR device may find its niche as a bailout option, primarily in a very specific subset of distally located wide neck aneurysms.

SUMMARY:Does the world need another ICA classification scheme? We believe so. The purpose of proposed angiography-driven classification is to optimize description of the carotid artery from the endovascular perspective. A review of existing, predominantly surgically-driven classifications is performed, and a new scheme, based on the study of NYU aneurysm angiographic and cross-sectional databases is proposed. Seven segments - cervical, petrous, cavernous, paraophthlamic, posterior communicating, choroidal, and terminus - are named. This nomenclature recognizes intrinsic uncertainty in precise angiographic and cross-sectional localization of aneurysms adjacent to the dural rings, regarding all lesions distal to the cavernous segment as potentially intradural. Rather than subdividing various transitional, ophthalmic, and hypophyseal aneurysm subtypes, as necessitated by their varied surgical approaches and risks, the proposed classification emphasizes their common endovascular treatment features, while recognizing that many complex, trans-segmental, and fusiform aneurysms not readily classifiable into presently available, saccular aneurysm-driven schemes, are being increasingly addressed by endovascular means. We believe this classification may find utility in standardizing nomenclature for outcome tracking, treatment trials and physician communication.

PURPOSE: To develop a semiautomatic method based on level set method (LSM) for carotid arterial wall thickness (CAWT) measurement. MATERIALS AND METHODS: Magnetic resonance imaging (MRI) of diseased carotid arteries was acquired from 10 patients. Ground truth (GT) data for arterial wall segmentation was collected from three experienced vascular clinicians. The semiautomatic variational LSM was employed to segment lumen and arterial wall outer boundaries on 102 MR images. Two computer-based measurements, arterial wall thickness (WT) and arterial wall area (AWA), were computed and compared with GT. Linear regression, Bland-Altman, and bias correlation analysis on WT and AWA were applied for evaluating the performance of the semiautomatic method. RESULTS: Arterial wall thickness measured by radial distance measure (RDM) and polyline distance measure (PDM) correlated well between GT and variational LSM (r = 0.83 for RDM and r = 0.64 for PDM, P < 0.05). The absolute arterial wall area bias between LSM and three observers is less than 10%, suggesting LSM can segment arterial wall well compared with manual tracings. The Jaccard Similarity (Js ) analysis showed a good agreement for the segmentation results between proposed method and GT (Js 0.71 +/- 0.08), the mean curve distance for lumen boundary is 0.34 +/- 0.2 mm between the proposed method and GT, and 0.47 +/- 0.2 mm for outer wall boundary. CONCLUSION: The proposed LSM can generate reasonably accurate lumen and outer wall boundaries compared to manual segmentation, and can work similar to a human reader. However, it tends to overestimate CAWT and AWA compared to the manual segmentation for arterial wall with small area.J. Magn. Reson. Imaging 2013;00:000-000. (c) 2013 Wiley Periodicals, Inc.

Atherosclerosis involving the carotid arteries has a high prevalence in the population worldwide. This condition is significant because accidents of the carotid artery plaque are associated with the development of cerebrovascular events. For this reason, carotid atherosclerotic disease needs to be diagnosed and those determinants that are associated to an increased risk of stroke need to be identified. The degree of stenosis typically has been considered the parameter of choice to determine the therapeutical approach, but several recently published investigations have demonstrated that the degree of luminal stenosis is only an indirect indicator of the atherosclerotic process and that direct assessment of the plaque structure and composition may be key to predict the development of future cerebrovascular ischemic events. The concept of "vulnerable plaque" was born, referring to those plaque's parameters that concur to the instability of the plaque making it more prone to the rupture and distal embolization. The purpose of this review is to describe the imaging characteristics of "vulnerable carotid plaques."

BACKGROUND AND OBJECTIVE: Treatment of non-saccular vertebrobasilar aneurysms remains highly challenging despite significant recent advances in endovascular techniques. Establishing the natural history of this heterogeneous disease, as best as currently available data allows, is crucial to help guide counseling and management. METHODS: A review of the literature was conducted to identify publications describing the presentation and natural history of vertebrobasilar dolichoectasia and non-saccular aneurysms. RESULTS: Nine studies of 440 patients met the analysis inclusion criteria. The majority of patients presented with ischemia, mass effect, or incidentally; hemorrhage was uncommon and overlapped with the population of vertebrobasilar dissection. Overall mortality was approximately 40% after 7 years of follow-up, with 43% of these deaths resulting from non-neurologic causes. Neurologic course was dominated by ischemic stroke rather than hemorrhage. Mass effect prognosis was especially poor, with 40% mortality after approximately 4 years. Incidentally discovered lesions which remain morphologically stable have a favorable long term course. CONCLUSIONS: Initial clinical presentation is a strong predictor of subsequent disease course. Although overall prognosis is poor, nearly half of all deaths resulted from non-neurologic causes, underscoring the importance of comprehensive medical management. Aneurysms characterized by expansion, established mass effect, or hemorrhage have a poor natural history, and may be considered for invasive treatment, which is increasingly endovascular in nature. Lesions presenting with ischemia or incidentally are likely best addressed with aggressive neurologic and overall medical management.

OBJECTIVE: To evaluate whether balance deficit in patients with multiple sclerosis (MS), as assessed with eyes opened (EO) and closed (EC), is associated with damage of different structures of the central nervous system (CNS). METHODS: Fifty patients with MS and 20 healthy controls (HCs) underwent static posturography to calculate the body's center of pressure displacement (COP path) with EO and EC. They were scanned using a 3.0T magnet to obtain PD/T2 and 3D-T1-weighted images of the brain and spinal cord. We determined the mid-sagittal cerebellum area (MSCA) and upper cervical cord cross-sectional area (UCCA). We also measured the patients' lesion volumes (T2-LVs) on the whole brain and at different infratentorial levels. RESULTS: MS patients had wider COP paths with both EO and EC (p < 0.001), and lower values in both MSCA (p = 0.01) and UCCA (p = 0.008) than HCs. The COP path with EO was associated with MSCA (Beta = - 0.58; p = 0.004) and T2-LV on middle cerebellar peduncles (Beta = 0.59; p = 0.002). The COP path with EC was associated with UCCA (Beta= - 22.74; p = 0.003) and brainstem T2-LV (Beta = 0.52; p = 0.01). CONCLUSIONS: Balance deficit in MS was related to atrophy of both the cerebellum and spinal cord, but the extent of COP path under the two different conditions (EO or EC) implied different patterns of damage in the CNS.

OBJECTIVE. The purpose of this study was to compare the type of plaque and the degree of stenosis in the carotid artery bifurcation and the carotid siphon to explore potential correlations between these parameters. MATERIALS AND METHODS. A total of 119 patients (87 men, 32 women; mean age, 69 years) were retrospectively studied using MDCT angiography. Component types of the carotid artery bifurcation and the carotid siphon plaque were defined according to attenuation values, and the volumes of each plaque component were calculated. The degree of stenosis was calculated according to the North American Symptomatic Endarterectomy Trial method. Data were compared using the Wilcoxon signed-rank test, Spearman correlation analysis, and receiver operating characteristic (ROC) analysis. RESULTS. The results of the Wilcoxon test showed a statistically significant difference (p = 0.0001) between the degree of stenosis at the carotid artery bifurcation and that at the carotid siphon. We observed a statistically significant difference (p = 0.0001) between the total volumes of the carotid artery bifurcation (mean value, 748 mm(3)) and the carotid siphon (mean value, 54 mm(3)) plaque. Moreover, the respective mean percentages of calcified, mixed, and lipid components of plaque were 17%, 56%, and 27% in the carotid artery bifurcation and 73%, 19%, and 8% in the carotid siphon, showing a statistically significant difference (p = 0.001). ROC analysis did not show association between carotid siphon plaque volume and previous cerebrovascular events (Az = 0.562; p = 0.149), whereas the total volume of the carotid artery bifurcation plaque-and, in particular, the volume of the lipid components-showed a statistically significant association (Az = 0.691, and Az = 0.758; p < 0.001). CONCLUSION. No significant association was found between presence of mixed and fatty components of plaque in the carotid artery bifurcation and presence of similar components in the carotid siphon. The carotid artery bifurcation total plaque volume (and, in particular, carotid artery bifurcation lipid volume) was associated with previous cerebrovascular events, whereas no association with the volume of carotid siphon plaque (and its subcomponents) was found.

OBJECTIVE. The amount of cerebral white matter lesions (WMLs) and the severity of carotid artery disease are correlated in this study. The association between the severity of WMLs and the volume of the different components of carotid artery plaque is also evaluated. MATERIALS AND METHODS. Fifty consecutive patients (39 men, 11 women; mean [SD] age, 71 +/- 9 years) with carotid artery stenosis who underwent carotid endarterectomy were included in this study. On admission, patients underwent head and neck CT angiography (CTA) and brain MRI. The CTA-based plaque volume and the percentages of the three main plaque components (fatty, mixed, and calcified) were calculated according to the attenuation values. Leukoaraiosis lesion volume on FLAIR images was determined using a semiautomated segmentation technique. Pearson correlation was conducted between the leukoaraiosis lesion volume on FLAIR images and the volumes of the different plaque components. RESULTS. Pearson correlation analysis was performed to determine WML volume versus total carotid plaque volume (rho = 0.2531; p = 0.0262), fatty plaque volume (rho = 0.387; p = 0.0005), mixed plaque volume (rho = 0.1709; p = 0.15), and calcified plaque volume (rho = 0.0146; p = 0.899). The WML volume was also compared against fatty plaque percentage (rho = 0.343; p = 0.0018), mixed plaque percentage (rho = 0.181; p = 0.124), and calcified plaque percentage (rho = -0.209; p = 0.068). CONCLUSION. The cerebral WML volume and the total volume of the plaque are correlated. The amount of fat within the plaque is an additional risk factor, whereas the calcified component seems to be protective.

Imaging of a 29-year-old man with seizures showed a frontal lobe mass with curvilinear narrow calcifications, cystic components and multiple flow-voids. An AVM was considered. A DSA confirmed the hypervascular nature of the lesion. It was resected and microscopic examination showed an anaplastic oligodendroglioma remarkable for a diffuse and hypertrophic vasculature with areas of frank vascular proliferation. The marked vascularity seen on the MRI, the gyriform calcifications and the cystic degeneration are all features which can be encountered in an AVM. This case illustrates that highly vascular malignant gliomas can simulate vascular lesions by radiology and may require an angiogram for diagnosis.