Citations

Background Characterization of acute ischemic stroke (AIS) clots has typically focused on two-dimensional histological analysis of the thrombus. The three-dimensional (3D) architecture and distribution of components within emboli have not been fully investigated. The aim of this study was to examine the composition and microstructure of AIS clots using histology and serial block-face scanning electron microscopy (SBFSEM). Methods As part of the multi-institutional STRIP registry, 10 consecutive AIS emboli were collected from 10 patients treated by mechanical thrombectomy. Histological and immunohistochemical analysis was performed to determine clot composition. SBFSEM was used to assess the ultrastructural organization of the clots and specific features of individual components. Results Quantification of Martius Scarlett Blue stain identified fibrin (44.4%) and red blood cells (RBCs, 32.6%) as the main components. Immunohistochemistry showed a mean platelet and von Willebrand factor content of 23.9% and 11.8%, respectively. The 3D organization of emboli varied greatly depending on the region analyzed. RBC-rich areas were composed mainly of tightly packed RBCs deformed into polyhedrocytes with scant fibrin fibers interwoven between cells. The regions with mixed composition showed thick fibrin fibers along with platelets, white blood cells and RBC clusters. Fibrin-rich areas contained dense fibrin masses with sparse RBC. In three cases, the fibrin formed a grid-like or a sponge-like pattern, likely due to thrombolytic treatment. Segmentation showed that fibrin fibers were thinner and less densely packed in these cases. Conclusions 3D-SEM provides novel and potentially clinically relevant information on clot components and ultrastructure which may help to inform thrombolytic treatment and medical device design.

AbstractEmbolectomy is one of the emergency procedures performed to remove emboli. Assessing the composition of human blood clots is an important diagnostic factor and could provide guidance for an appropriate treatment strategy for interventional physicians. Immunostaining has been used to identity compositions of clots as a gold‐standard procedure, but it is time‐consuming and cannot be performed in situ. Here, we proposed that the optical attenuation coefficient of optical coherence tomography (OCT) can be a reliable indicator as a new imaging modality to differentiate clot compositions. Fifteen human blood clots with multiple red blood cell (RBC) compositions from 21% to 95% were prepared using healthy human whole blood. A homogeneous gelatin phantom experiment and numerical simulation based on the Lambert–Beer's law were examined to verify the validity of the attenuation coefficient estimation. The results displayed that optical attenuation coefficients were strongly correlated with RBC compositions. We reported that attenuation coefficients could be a promising biomarker to guide the choice of an appropriate interventional device in a clinical setting and assist in characterizing blood clots.

Background Initial studies investigating correlations between stroke etiology and clot composition are conflicting and do not account for clot size as determined by area. Radiological studies have shown that cardioembolic strokes are associated with shorter clot lengths and lower clot burden than non-cardioembolic clots. Objective To report the relationship between stroke etiology, extracted clot area, and histological composition at each procedural pass. Methods As part of the multi-institutional RESTORE Registry, the Martius Scarlett Blue stained histological composition and extracted clot area of 612 per-pass clots retrieved from 441 patients during mechanical thrombectomy procedures were quantified. Correlations with clinical and procedural details were investigated. Results Clot composition varied significantly with procedural passes; clots retrieved in earlier passes had higher red blood cell content (H4=11.644, p=0.020) and larger extracted clot area (H4=10.730, p=0.030). Later passes were associated with significantly higher fibrin (H4=12.935, p=0.012) and platelets/other (H4=15.977, p=0.003) content and smaller extracted clot area. Large artery atherosclerotic (LAA) clots were significantly larger in the extracted clot area and more red blood cell-rich than other etiologies in passes 1–3. Cardioembolic and cryptogenic clots had similar histological composition and extracted clot area across all procedural passes. Conclusion LAA clots are larger and associated with a large red blood cell-rich extracted clot area, suggesting soft thrombus material. Cardioembolic clots are smaller in the extracted clot area, consistent in composition and area across passes, and have higher fibrin and platelets/other content than LAA clots, making them stiffer clots. The per-pass histological composition and extracted clot area of cryptogenic clots are similar to those of cardioembolic clots, suggesting similar formation mechanisms.

Purpose To assess whether an asymmetry exists in the prevalence of carotid artery intraplaque hemorrhage (IPH) between right- and left-sided arteries. Materials and methods The records of all patients with atherosclerotic carotid artery disease that underwent neck magnetic resonance angiography imaging with high-resolution plaque sequences between 2017 and 2020 at our institution were retrospectively reviewed. The prevalence of stenosis and IPH was determined for all patients and compared between the left and right carotid arteries of those with unilateral anterior circulation ischemic strokes. Multiple regression analysis was performed to determine potential independent associations of IPH laterality with ischemic strokes. Results A total of 368 patients were included overall and 241 were male (65.4%). There were a total of 125 asymptomatic patients and 211 patients with unilateral anterior circulation ischemic strokes. Of patients with ischemic strokes, 55.5% had left-sided strokes compared with 44.5% who had right-sided strokes ( p = 0.03). Patients with left-sided strokes had a higher prevalence of ipsilateral IPH than those with right-sided strokes (64.1% versus 36.2%, p < 0.0001), despite similar degrees of stenosis. Both age (odds ratio (OR): 1.0; 95% confidence interval (CI): 1.0–1.1; p = 0.007) and the presence of left-sided IPH (OR: 3.2; 95% CI: 1.5–6.8; p = 0.003) were independently associated with unilateral ischemic strokes. Conclusions Left-sided plaques more frequently have IPH and may be more likely to result in ipsilateral ischemic strokes compared with right-sided plaques. The underlying mechanism of asymmetric distribution of IPH between right and left carotids remains unclear.

Background and Purpose: Few community-based studies investigating young adult strokes exist. The aim of this study was to determine the diagnostic yield of head and neck CTA in evaluation of anterior circulation ischemic stroke in young adults. Materials and Methods: This retrospective review is limited to patients between the ages of 18-50 presenting to the Mayo Clinic Rochester emergency department or referred from smaller institutions in adjacent counties. Patients with posterior circulation infarcts, amaurosis fugax, central retinal artery occlusion or transient ischemic attacks were excluded. The presence of carotid dissection, webs, plaque, or other high-risk lesions were recorded. Results: A total of 136 patients met inclusion criteria. Mean degree of carotid stenosis ipsilateral to infarct was 14.1%, compared to 6.5% on the contralateral side (p = .006). Ipsilateral mean carotid wall thickness measured .79 mm, compared to contralateral thickness of .80 mm (p = .51). Ipsilateral low-density plaque was observed in 22 patients (16.2%), and 21 patients (15.4%) on the contralateral side (p = .87). Ipsilateral calcified plaque was observed in 37 patients (27.2%), and 29 patients (21.3%) on the contralateral side (p = .31). 20 (14.7%) ipsilateral dissections were noted, compared to 4 (2.9%) contralateral dissections (p = .001). 3 (2.2%) ipsilateral carotid webs were identified, compared to 0 contralateral webs (p = .25). Conclusion: Carotid dissection was the most common cause of anterior circulation infarct identified on cervical CTA in this population. Carotid webs and atherosclerosis were not common findings.

Abstract BACKGROUND Spinal epidural arteriovenous fistulas (SEDAVFs) are an increasingly recognized form of spinal vascular malformation and are distinct from spinal dural arteriovenous fistulas (SDAVFs). Differentiating between these 2 entities is important as operative strategies often differ based on angioarchitecture. OBJECTIVE To compare demographic, clinical, anatomic, and imaging findings of SDAVFs and SEDAVFs. METHODS Consecutive patients diagnosed and/or treated for SDAVF or SEDAVF at our institution between January 2000 and November 2018 were included. Data were collected on demographics, clinical presentation, and imaging findings. All cross-sectional and angiographic imaging were reviewed. To compare continuous variables, t -test was used Chi-squared was used for categorical variables. RESULTS A total of 169 patients were included. In total 47 patients had SEDAVFs and 122 patients had SDVAFs. Clinical presentation and magnetic resonance imaging (MRI) imaging findings were similar between the 2 groups. SEDAVF patients were significantly more likely to have an epidural venous pouch on gadolinium bolus MR angiography (MRA) (0.0% vs 92.1%, P < .0001). SEDAVFs were more commonly located in the lumbar and sacral spine than SDAVFs (85.1% vs 34.4%, P < .0001). When in the lumbar spine, SEDAVFs unlike SDAVFs were more likely to involve the most caudal segments (L4 and L5, P = .02). CONCLUSION SEDAVF share clinical and radiological findings similar to SDAVFS, including high T2 cord signal, cord enhancement, and perimedullary flow voids on conventional MRI. However, they have a characteristic appearance on spinal MRA and DSA with a pouch of epidural contrast. SEDAVFs are more commonly located in the lumbosacral spine.

Abstract BACKGROUND A number of studies have demonstrated spinal anomalies associated with Klippel-Trenaunay syndrome (KTS). To date, there are no large consecutive series examining the prevalence and subtype distribution of spinal neurovascular malformations in patients with KTS. OBJECTIVE To report the spectrum and incidence of spinal neurovascular manifestations in the KTS population. METHODS This was a cross-sectional study. Consecutive patients with definite KTS as defined by International Society for the Study of Vascular Anomalies criteria who underwent spinal neuroimaging at our institution were included. All studies were evaluated by a staff neuroradiologist and a senior radiology resident for the presence of developmental venous anomalies, cavernous malformations (CMs), and arteriovenous shunts (AVS). RESULTS A total of 116 patients with definite KTS who underwent spinal neuroimaging were included. A total of 23 neurovascular anomalies were found in 19 patients (16.4%), including 4 patients with multiple anomalies. These included 5 patients with spinal cord CMs (4.3%), 14 patients with a paraspinal or epidural venous malformation (12.1%), and 4 patients with an AVS (3.4%). Of the AVS, 3 were epidural arteriovenous fistulas, 1 of which likely formed de novo in an epidural venous malformation. One was a conus medullaris arteriovenous malformation. CONCLUSION Our study cohort of 116 KTS patients demonstrated a wide spectrum of spinal neurovascular anomalies with a relatively high prevalence. Potential phenotypic descriptions of KTS should include the possibility for spinal neurovascular anomalies.

Dural arteriovenous fistulas of the skull base commonly present with pulsatile tinnitus. In our experience, transvenous embolization of dural arteriovenous fistulas of the skull base represents a safe and effective treatment modality due to its precision in treatment of the site of convergence of all feeding arteries and the low risk of ischemic complications. We present a case of an adult patient who presented to our institution with pulsatile tinnitus several months following a motor vehicle accident. Cerebral angiography demonstrated a dural arteriovenous fistula at the junction of the posterior condylar vein and suboccipital venous plexus supplied by branches of the vertebral artery, occipital artery, and ascending pharyngeal artery. In this operative video we demonstrate this technique and provide an in-depth discussion of our treatment decision-making process and the anatomical considerations involved in treating this lesion. Video 1