Influence of framing coil orientation and its shape on the hemodynamics of a basilar aneurysm model.

Aneurysms are bulges of an artery, which require clinical management solutions. Due to the inherent advantages, endovascular coil filling is emerging as the treatment of choice for intracranial aneurysms (IAs). However, after successful treatment of coil embolization, there is a serious risk of recurrence. It is well known that optimal packing density will enhance treatment outcomes. The main objective of endovascular coil embolization is to achieve flow stasis by enabling significant reduction in intra-aneurysmal flow and facilitate thrombus formation. The present study numerically investigates the effect of framing coil orientation on intra-aneurysmal hemodynamics. For the purpose of analysis, actual shape of the embolic coil is used, instead of simplified ideal coil shape. Typically used details of the framing coil are resolved for the analysis. However, region above the framing coil is assumed to be filled with a porous medium. Present simulations have shown that orientation of the framing coil loop (FCL) greatly influences the intra-aneurysmal hemodynamics. The FCLs which were placed parallel to the outlets of basilar tip aneurysm (Coil A) were found to reduce intra-aneurysmal flow velocity that facilitates thrombus formation. Involving the coil for the region is modeled using a porous medium model with a packing density of 20 % . The simulations indicate that the framing coil loop (FCL) has a significant influence on the overall outcome.

Endovascular and percutaneous embolization of a giant post traumatic arteriovenous fistula of inferior epigastric vessels.

BACKGROUND: Arteriovenous fistulas involving the anterior abdominal wall can result from trauma. Such fistulas may remain asymptomatic and undetected for a prolonged duration of time. They tend to recruit multiple arterial feeders with remodelling in the feeding arteries, making them challenging to treat. CASE PRESENTATION: We discuss a rare case of a 60-year-old male who presented with complaints of a progressive painless swelling in right lower abdomen. There was a history of blunt injury to abdomen at the same site during alleged road traffic accident 3 years ago. On CT angiography, an arteriovenous fistula was localised to the anterior abdominal wall arising predominantly from the right inferior epigastric artery with a giant venous sac and terminating as a tortuous single venous channel into the right external iliac vein. Few other small feeders were also seen arising from branches of right superior epigastric artery along Winslow's pathway. The main challenge in endovascular management of this patient was embolization of a high flow shunt with a large venous sac and multiple arterial feeders. The dominant arterial feeder was embolized using vascular plug. The superficial location of the lesion offered an additional percutaneous window besides endovascular approach. The venous sac was percutaneously accessed and embolized using n-butyl cyanoacrylate after balloon occlusion of outflow vein. On follow up ultrasonographic evaluation at 3 months, near complete thrombosis of the venous sac was achieved. CONCLUSIONS: Traumatic arteriovenous fistulas involving the inferior epigastric vessels are rare clinical entities. CT angiogram and digital subtraction angiography help in the optimal diagnosis and treatment planning. The use of mechanical embolization devices to cause flow arrest offers an opportunity to use liquid embolic agents which offer better percolation within the lesion. Interventional radiology offers an ideal management of these complex high flow fistulas with a good technical success and acceptable safety profile.

Evaluating the diagnostic performance of non-contrast magnetic resonance angiography sequences in the pre-procedural comprehensive analysis of direct carotid cavernous fistula.

PURPOSE: Endovascular treatment of direct carotid cavernous fistula (DCCF) requires invasive diagnostic cerebral angiography for diagnosis and planning; however, a less invasive modality like magnetic resonance angiography (MRA) can be useful, especially in high-risk cases. This single-centre study evaluated a newer MR angiography (MRA) sequence, silent MRA and the traditional time of flight (TOF) MRA for pre-procedural treatment planning of DCCF. METHODS: All consecutive DCCF patients who underwent TOF, silent MRA and diagnostic cerebral angiography were included in the study. Angiographic features like rent size, location, draining veins and collateral communicating arteries were analysed and compared between the two MRA sequences, with digital subtraction angiography (DSA) as the gold standard. RESULTS: Fifteen patients were included in the study. TOF MRA exhibited better sensitivity (76.9% vs 69.2%) in identifying the rent location, correctly pinpointing the location in 93.3% compared to 73.3% with silent MRA. Both MRA sequences showed good agreement with DSA for primary sac and rent size. TOF MRA correctly identified 86.2% of 210 total venous structures compared to 96% by silent MRA. Silent MRA demonstrated higher sensitivity (90% vs 76%) and accuracy (87.69 vs 94.36) in visualisation of involved veins compared to TOF MRA. CONCLUSION: Arterial characteristics of DCCF like rent location and rent size were better assessed by TOF MRA. Although both MRA identified venous features, silent MRA correlated better with DSA irrespective of the size and proximity to the site of the fistula. Combining both sequences can evaluate various angioarchitectural features of DCCF useful for therapeutic planning.

CT angiographic patterns predict carotid pseudo-occlusion in acute ischemic stroke.

Background: Identifying carotid pseudo-occlusion (PO) from true occlusion (TO) has implications in determining the candidacy and feasibility of successful endovascular thrombectomy (EVT) in acute ischemic stroke (AIS). Purpose: We reviewed the computed tomography angiographic (CTA) patterns differentiating a PO from a TO and analyzed the rate of successful recanalization after EVT. Materials and Methods: Patients with AIS and proximal internal carotid artery (ICA) occlusion who underwent EVT from 2014 to 2021 were identified. The patterns of carotid occlusion in CTA were classified into beak, dome, and flat patterns and correlated with microcatheter digital subtraction angiography (DSA) as PO and TO. The rates of successful recanalization in PO and TO were analyzed. Results: Of the 24 patients, 16 (66%) had ICA PO and eight (33%) had TO in DSA. A beak pattern of the proximal ICA on CTA was significantly higher among the PO group patients (87.5% vs. 25%, P = 0.005), and a flat pattern was significantly higher among the TO group patients (50% vs. 12%, P = 0.005). A gradual contrast decline of the proximal ICA on CTA images was seen only in PO group patients (85.7% vs. 0%, P = 0.05). There was no significant difference in the rate of successful recanalization between PO and TO group patients (81.25% vs. 62.5%, P = 0.362). Conclusion: Beak pattern and gradual contrast decline at the proximal ICA occlusion site in CTA are suggestive of carotid PO. Identification of PO in CTA can help in planning intervention strategies and prognostication.

Technical Success, Midterm Primary Patency, and Factors Affecting Primary Patency of Subintimal Angioplasty Followed by Vasculomimetic Stenting for Trans-Atlantic Intersociety Consensus II C and D Femoropopliteal Arterial Disease-A Prospective Study.

Background The best option among the endovascular options in long, complex femoropopliteal (FP) lesions, and factors affecting the patency have yet to be well described. There are few studies describing the mid- and long-term patency of endovascular stents in long-segment FP occlusions. Aim This study aimed to determine the technical success and mid-term patency of subintimal angioplasty with vasculomimetic stenting in Trans-Atlantic Inter-Society Consensus II (TASC) C and D FP disease. The patient and imaging factors that affect primary patency were also analyzed. Methods and Materials A single-center prospective study was performed on 52 consecutive patients undergoing endovascular treatment for TASC C and D FP disease from 2017 to 2021. Angioplasty with stenting was performed in all patients and followed up for 36 months. Endpoints were primary patency rates and amputation-free survival of the limb. Kaplan-Meier curves were used to see patency rates and amputation-free survival rates. Results A total of 52 patients underwent stenting with a technical success rate of 100% if the sub-intimal arterial flossing with antegrade-retrograde intervention (SAFARI) technique was used. Primary stent patency at 6, 12, 18, 24, and 36 months was 89.8, 81.4, 76.2, 71.4, and 62.5%, respectively. Amputation-free survival was 98, 95.6, 91.8, and 85.7% at 12, 24, 30, and 36 months, respectively. Cox proportional regression analysis showed smoking and vessel wall calcium score more than 270 degrees as independent predictors of loss of primary patency (hazard ratio 0.35 confidence interval [CI]: 0.003-0.448) and 0.102 (CI: 0.022-0.47), respectively. Conclusion Subintimal angioplasty with vasculomimetic stent has good midterm patency in and amputation-free survival in long-segment FP occlusions. Smoking and severe vessel wall calcification adversely affect patency.

Thrombus Attenuation Gradient Can Predict Successful First-Pass Recanalization Following Stentriever Thrombectomy.

OBJECTIVE: Computed tomography angiography (CTA) derived thrombus enhancement characteristics can predict first-pass recanalization. We studied whether dynamic contrast kinetics within the clot in multiphase CTA can predict first-pass recanalization following stentriever thrombectomy. METHODS: Patients with acute large vessel occlusive stroke evaluated with multiphasic CTA who underwent stentriever thrombectomy were selected. Thrombus perviousness on various phases including arterial, venous, and delayed phases was calculated. Thrombus attenuation gradient (TAG), defined as average attenuation difference between adjacent phases, was also evaluated and correlated with successful first-pass outcome (modified Treatment in Cerebral Ischemia score ≥2b). RESULTS: Of 69 patients, 32 (47%) had successful first-pass recanalization (group 1), and 37 (53%) required >1 attempt (group 2). TAG showed significant differences in arterial-plain and venous-arterial phases. The early increase in TAG was seen in group 1 in the arterial-plain phase, as opposed to group 2 (12.6 vs. 9, P = 0.01), which plateaued in the venous-arterial phase for group 1 and showed a further increase in group 2 (2.1 vs. 5.1, P = 0.02). A cutoff value of 9.2 HU for arterial-plain phase (P = 0.001) and 4.2 HU (P = 0.001) for venous-arterial phase was predictive of first-pass effect. Combining 2 metrics had an odds ratio of 2.8 for first-pass recanalization (P = 0.035). Accuracy evaluated in a validation cohort yielded 74%. Other features including histology were not significant. CONCLUSIONS: TAG evaluated from multiphase CTA can predict first-pass effect in stentriever thrombectomy.

Numerical investigation of unruptured middle cerebral artery bifurcation aneurysms: influence of aspect ratio.

An aneurysm is a disease condition, which is due to the pathological weakening of an arterial wall. These aneurysms are often found in various branch points and bifurcations of an artery in the cerebral circulation. Most aneurysms come to medical attention, either due to brain hemorrhages caused by rupture or found unruptured. To consider surgically invasive treatment modalities, clinicians need scientific methods such as, hemodynamic analysis to assess rupture risk. The arterial wall loses its structural integrity when wall shear stress (WSS) and other hemodynamic parameters exceed a certain threshold. In the present study, numerical simulations are carried out for unruptured middle cerebral artery (MCA) aneurysms. Three distinct representative sizes are chosen from a larger patient pool of 26 MCA aneurysms. Logically, these aneurysms represent three growth stages of any patient with similar anatomical structure. Simulations are performed to compare the three growth phases (with different aspect ratios) of an aneurysm and correlate their hemodynamic parameters. Simulations with patient specific boundary conditions reveal that, aneurysms with a higher aspect ratio (AR) correspond to an attendant decrease in both time-averaged wall shear stress (TAWSS) and spatial wall shear stress gradients (WSSG). Smaller MCAs were observed to have higher positive wall shear stress divergence (WSSD), exemplifying the tensile nature of arterial wall stretching. Present study identifies positive wall shear stress divergence (PWSSD) to be a potential biomarker for evaluating the growth of an aneurysm.

Reverse Flow Thromboembolism From Distal Subclavian Artery Aneurysm Due to Arterial Thoracic Outlet Syndrome and Posterior Circulation Stroke- Role of Dynamic Doppler Imaging.

INTRODUCTION: Arterial thoracic outlet syndrome (aTOS) is the least common among the 3 subtypes of thoracic outlet syndrome and can be the cause of posterior circulation infarction due to thrombus from a secondary thrombosed subclavian-axillary artery aneurysm. CASE REPORT: Here, we report a case of a 51-year-old man who presented to our institute with sudden onset vertigo, dizziness, vomiting, gait imbalance, and visual field defects immediately after strenuous exercise. Computed tomography angiography revealed bilateral cervical ribs with aneurysmal dilatation of the left distal subclavian and proximal axillary arteries. The computed tomography also revealed subacute infarcts in the bilateral cerebellar hemispheres, as well as in the bilateral occipital lobes. Color Doppler evaluation of the subclavian artery after hyperabduction of the ipsilateral arm revealed a continuous reversal of flow in the subclavian artery, which reached the vertebral ostia. The left cervical rib was resected, aneurysm was repaired, and the patient remained asymptomatic on follow-up. CONCLUSION: Posterior circulation stroke caused by the ipsilateral thrombosed subclavian artery aneurysm in an adult patient with aTOS due to a complete cervical rib is rare. A high index of suspicion should be present for thoracic outlet syndrome in patients with stroke and upper-limb arterial claudication symptoms. Dynamic Doppler evaluation in such patients can be used to demonstrate the underlying pathomechanism, and definitive surgical treatment can prevent further ischemic episodes. Posterior circulation stroke caused by partially thrombosed distal subclavian and axillary artery aneurysms due to aTOS is rare.

AutoML accurately predicts endovascular mechanical thrombectomy in acute large vessel ischemic stroke.

Background and objective: Automated machine learning or autoML has been widely deployed in various industries. However, their adoption in healthcare, especially in clinical settings is constrained due to a lack of clear understanding and explainability. The aim of this study is to utilize autoML for the prediction of functional outcomes in patients who underwent mechanical thrombectomy and compare it with traditional ML models with a focus on the explainability of the trained models. Methods: A total of 156 patients of acute ischemic stroke with Large Vessel Occlusion (LVO) who underwent mechanical thrombectomy within 24 h of stroke onset were included in the study. A total of 34 treatment variables including clinical, demographic, imaging, and procedure-related data were extracted. Various conventional machine learning models such as decision tree classifier, logistic regression, random forest, kNN, and SVM as well as various autoML models such as AutoGluon, MLJAR, Auto-Sklearn, TPOT, and H2O were used to predict the modified Rankin score (mRS) at the time of patient discharge and 3 months follow-up. The sensitivity, specificity, accuracy, and AUC for traditional ML and autoML models were compared. Results: The autoML models outperformed the traditional ML models. For the prediction of mRS at discharge, the highest testing accuracy obtained by traditional ML models for the decision tree classifier was 74.11%, whereas for autoML which was obtained through AutoGluon, it showed an accuracy of 88.23%. Similarly, for mRS at 3 months, the highest testing accuracy of traditional ML was that of the SVM classifier at 76.5%, whereas that of autoML was 85.18% obtained through MLJAR. The 24-h ASPECTS score was the most important predictor for mRS at discharge whereas for prediction of mRS at 3 months, the most important factor was mRS at discharge. Conclusion: Automated machine learning models based on multiple treatment variables can predict the functional outcome in patients more accurately than traditional ML models. The ease of clinical coding and deployment can assist clinicians in the critical decision-making process. We have developed a demo application which can be accessed at https://mrs-score-calculator.onrender.com/.

A novel parameter for the prediction of rupture risk of cerebral aneurysms based on morphology.

Neurosurgeons often encounter dilemmas in the clinical management of cerebral aneurysms owing to an uncertainty of their rupture status and rupture risk. This study evaluates the influence of natural frequency of an aneurysm, as a novel morphological parameter to understand and analyze rupture status and risk prediction. In this work, we employ the natural frequency of 20 idealized and 50 patient specific aneurysms. The natural frequency of patient specific aneurysms is then compared against their rupture status. A strong correlation was observed between various morphological indicators and natural frequency for ideal and patient specific geometries. A statistical analysis with both Mann Whitney U test and T-test for rupture status against natural frequency has given a p-value less than 0.01 indicating a strong correlation between them. The correlation of morphological parameters with natural frequency from Pearson correlation coefficient and T-test suggests a holistic reflection of their effects on the natural frequency of an aneurysm. Thus, natural frequency could be a good indicator to discern the rupture potential of an aneurysm. The correlation between rupture status and natural frequency makes it a novel parameter that can differentiate between ruptured and unruptured patient specific aneurysms.

Non-invasive angiographic analysis of dural carotid cavernous fistula using time-of-flight MR angiography and silent MR angiography: a comparative study.

BACKGROUND: A non-invasive, reliable imaging modality that characterizes cavernous sinus dural arteriovenous fistula (CSDAVF) is beneficial for diagnosis and to assess resolution on follow-up. PURPOSE: To assess the utility of 3D time-of-flight (TOF) and silent magnetic resonance angiography (MRA) for evaluation of CSDAVF from an endovascular perspective. MATERIAL AND METHODS: This prospective study included 37 patients with CSDAVF, who were subjected to digital subtraction angiography (DSA) and 3-T MR imaging with 3D TOF and silent MRA. The main arterial feeders, fistula site, and venous drainage pattern were evaluated, and the results were compared with DSA findings. The diagnostic confidence scores were also recorded using a 4-point Likert scale. RESULTS: Silent MRA correlated better for shunt site localization and angiographic classification (86% vs. 75% and 83% vs. 75%, respectively) compared to TOF MRA. The proportion of arterial feeders detected was marginally significant for silent MRA over TOF MRA sequences (92.8% vs. 89.5%; P=0.048), though for veins both were comparable. Sensitivity of silent MRA was higher for identification of cortical venous reflux (CVR) (90.9% vs. 81.8%) and deep venous drainage (82.4% vs. 64.7%), while specificity was >90% for both modalities. The overall diagnostic confidence score fared better for silent MRA for venous assessment (P < 0.001) as well as fistula point identification (P < 0.001), while no significant difference was evident with TOF MRA for arterial feeders (P=0.06). CONCLUSION: Various angiographic components of CSDAVF could be identified and delineated by 3D TOF and silent MRA, though silent MRA was superior for overall diagnostic assessment.

Non-invasive assessment of cerebral hemoglobin parameters in intracranial dural arteriovenous fistula using functional near-infrared spectroscopy-A feasibility study.

Purpose: The purpose of this study was to assess the feasibility of non-invasive assessment of cerebral hemodynamics using functional near-infrared spectroscopy (fNIRS) in patients with intracranial dural arteriovenous fistula (DAVF) and to correlate the hemodynamic changes with definitive endovascular treatment. Methodology: Twenty-seven DAVF patients and 23 healthy controls underwent 20-mins task-based functional near-infrared spectroscopy and neuropsychology evaluation. The mean change in the hemoglobin concentrations obtained from the prefrontal cortex was assessed for oxyhemoglobin, deoxyhemoglobin, and oxygen saturation (HbO, HbR, and SO2, respectively). The fNIRS data were analyzed and correlated with improvement in neuropsychology scores at 1-month follow-up. Results: There was a significant reduction in HbO in the patient group, while it increased in controls (-2.57E-05 vs. 1.09E-04 mM, p < 0.001). The reduced HbO significantly improved after embolization (-2.1E-04 vs. 9.9E-04, p = 0.05, q = 0.05). In patients with aggressive DAVF (Cognard 2B and above), the change was highly significant (p < 0.001; q = 0.001). A moderate correlation was observed between MMSE scores and HbO changes (ρ = 0.4). Conclusion: fNIRS is a useful non-invasive modality for the assessment of DAVF, and could potentially assist in bedside monitoring of treatment response.

A Prospective Study Comparing the Three-Dimensional Rotational Angiography and Two-Dimensional Digital Subtraction Angiography in Evaluation of Brain Arteriovenous Malformations.

Background: Complex angioarchitecture of brain arteriovenous malformations (BAVM) are often difficult to evaluate with standard imaging technique of digital subtraction angiography (DSA). These details are better provided by 3D rotational angiography (3D-RA). Objective: The aim of the study is to compare two-dimensional digital subtraction angiography (2D-DSA) and 3D rotational angiography in the evaluation of BAVM angiographic architecture. Materials and Methods: 2D-DSA and 3D-RA of 167 consecutive patients with BAVM were analyzed for arterial feeders, nidal patterns, and detection of flow-related aneurysms, arteriovenous fistulous components, venous drainage, and draining vein stenosis. Results: 3D-RA detected a significantly higher number of aneurysms and draining venous stenoses (P < 0.001). The detected number of true intranidal aneurysms was significantly higher with 3D-RA (n = 94) vs 2D-DSA (n = 34) (P < 0.001). 2D-DSA has low sensitivity (43.1%) and specificity (73.4%) for detecting intranidal aneurysms. 3D-RA detected a significantly higher number (12.6%) of BAVM patients with feeding artery aneurysms as compared to 2D-DSA (8.4%), P value of 0.004. 3D-RA accurately depicted the distal course of dominant arterial feeders and fistulous sites in BAVMs. Direct arteriovenous communications were evident in 31.1% with 3D-RA, as compared to 2D-DSA (15%) with P value < 0.0001. A significantly higher number of draining vein stenosis was detected with 3D-RA (21.6%) as compared to 2D-DSA (13.2%), P value < 0.001. Conclusion: 3D-RA is better than 2D-DSA for detecting BAVM-associated flow-related aneurysms, distal course of the dominant arterial feeders, direct visualization of the fistulous components, deep venous drainage, and draining venous stenosis; findings imperative for making a prudent therapeutic decision.

Semi-automated mapping of occluded arterial segments in acute large vessel stroke from computed tomography angiography.

OBJECTIVES: Catheterisation of occluded artery is the most crucial step in the mechanical thrombectomy of large vessel occlusions. Being a blind procedure, potential major untoward events could be anticipated at this stage. In this study, we evaluated the feasibility of reconstruction of the occluded vascular segment from CT angiography, exploiting the attenuation difference between the clot and adjacent brain parenchyma. METHODS AND RESULTS: Twenty-five patients with large vessel occlusion who achieved TICI2B/3 recanalization were identified. The semi-automated reconstruction was done using an open-source 3D segmentation software by two observers. The generated arterial anatomy was categorized as congruent, if all the major arterial segments namely, internal carotid artery, M1 middle cerebral artery, bifurcation, and major divisions matched with post thrombectomy angiograms. The discrepancy of one or more than one arterial segment was classified as mild or total mismatch respectively. Congruent arterial mapping was possible in 88% and 92 % patients for observer 1 and observer 2 respectively, while mild mismatch was noted in two patients for both the observers. Mismatch mostly occurred in superior division for both observers(100% vs 66.6%). The interrater agreement was good (0.77) and the accuracy was not influenced by the length of the clot. The median time for reconstruction was 4 minutes for both the observers (p - 0.21). CONCLUSION: Delineation of the anatomy of the occluded major intracranial artery is possible and corresponds with the actual anatomy. It could be used as a guide during thrombectomy procedures.

Mechanical Thrombectomy in Acute Ischemic Stroke: Angiographic Predictors of Outcome.

Background: In patients with acute ischemic stroke with large vessel occlusion, various angiographic features are important in patient selection and predicting outcome. Objective: We evaluated angiographic features like collaterals, clot burden score, angiographic recanalization, number of passes, and intracranial atherosclerotic disease (ICAD) with the functional outcome at 90 days. Materials and Methods: This was a retrospective analysis of prospectively collected data of 163 patients with acute ischemic stroke with large vessel occlusion who underwent mechanical thrombectomy within 24 hours of symptom onset. Angiographic data were reviewed blinded to clinical data. The outcome was defined as modified Rankin scale (mRS) at 90 days (good outcome mRS ≤2). Results: The median age of patients was 60 years and 34.4% were females. The median National Institutes of Health Stroke Scale (NIHSS) and Alberta Stroke Programme Early CT Score (ASPECTS) at admission were 17 and 6, respectively. On bivariate analysis, ASPECTS was >6, clot burden score was ≥7, recanalization of TICI was ≥2b, absence of ICAD, showed a positive correlation with the good outcome at 90 days (P-values of 0.003, 0.0001, and 0.03, respectively). Multiple attempts of device passes were associated with poor recanalization (P = 0.001) and it was seen more in ICAD patients. On multivariate analysis, independent predictors of poor outcome were clot burden score <7 (P = 0.043) and TICI score <2b (P = 0.048). Out of 41 patients (26%) with ICAD, 29 had a poor outcome at 90 days. Conclusion: Lower clot burden and less degree of recanalization were associated with poor outcome in acute ischemic stroke due to Large vessel occlusion (LVO). The presence of ICAD also predicted poor outcome.

Does thrombus imaging characteristics predict the degree of recanalisation after endovascular thrombectomy in acute ischaemic stroke?

BACKGROUND: Identification of computed tomography (CT) thrombus imaging characteristics can predict the degree of recanalization and outcome after endovascular thrombectomy (EVT) in patients with acute ischaemic stroke and large vessel occlusion. AIM: We analyzed the thrombus imaging characteristics and procedural factors and correlated with the degree of recanalization and functional outcome after EVT. METHODS: We evaluated the thrombus imaging characteristics (hyperdense MCA sign, thrombus location, length and thrombus permeability) from thin slice CT and CT angiogram. In addition, groin to recanalization time, number of passes, and EVT technique were documented. The primary outcome was degree of recanalization (mTICI score) and secondary outcome was modified Rankin scale (mRS) at 3 months. RESULTS: The mean age of 102 patients was 60.5±11.8 years. Patients with hyperdense MCA sign (90 % vs 75%, p=0.07) and permeable thrombus (86 % vs 70 %, p=0.09) had good recanalization (mTICI grade 2b,2c or 3). The requirement of <3 passes (90 % vs 62 %, p= 0.001) was associated with good recanalization. Multiple logistic regression analysis showed thrombus permeability (OR 5.9; 95% CI 1.3-26.6, p=0.02), use of stent retreiver alone (without aspiration) (OR 5.4; 95% CI 1.3-22.5, p=0.02) and a puncture to recanalization ≤60 minutes (OR 7.9; 95% CI 1.7-36.8; p=0.008) were associated with good recanalization. The requirement of ≥3 passes was associated with poor functional outcome (OR 3.4;95% CI 1.2-9.8; p=0.02). CONCLUSIONS: Thrombus permeability was a predictor of successful recanalization after EVT. The requirement of three or more passes during EVT was associated with poor recanalization and poor functional outcome.

The Impact of Time to Reperfusion on Recanalization Rates and Outcome After Mechanical Thrombectomy: A Single Center Experience.

Background: Timely and effective recanalization to salvage the penumbra is the main determinant of outcome in acute ischemic strokes. Randomized controlled trials on late window mechanical thrombectomy (MT) have proved its safety and efficacy upto 24 h after stroke onset. We looked at the impact of time to reperfusion on vessel recanalization rates and short-term outcome in patients undergoing MT for large vessel occlusion. Methods: The clinical, imaging, and outcome of all patients undergoing MT upto 24 h from last seen normal was extracted from a prospectively maintained ischemic stroke database from January 2012 till September 2019. Results: There were 145 patients with a mean (SD) age of 58.2 (±14) years. Of them, 28 had wake up/unknown time of onset stroke and 9 presented beyond >360 min. There were 23 vertebrobasilar strokes. Median National Institute of Health Stroke scale score (NIHSS) at admission was 16.4 (Inter quartile range (IQR) 12-21). CT-Alberta Stroke program early CT score (CT-ASPECTS) was excellent (8-10) in 39 (31.6%) and fair (5-7) in 77 (63.6%) patients in anterior circulation strokes. About 25% underwent bridging therapy. Recanalization rates did not differ between those presenting early (<6 h) versus wake up strokes and late presenting patients (81.79% vs 71.9%). Symptomatic Intracerebral hemorrhage (ICH) occurred in 5%. At 3 months, excellent outcome (modified rankin scale <2) was observed in 28.9%. While Admission NIHSS remained strong predictor of poor outcome at 3 months, delay in presentation did not impact MT outcome (37.5% vs 45.79% and P = 0.460). Conclusions: The recanalization rates were similar in patients irrespective of the time to reperfusion from stroke onset. The functional outcome was not inferior in late presenters selected by advanced imaging.

Double-barrel plugging in a recurrent aorto-enteric fistula.

Aorto-enteric fistulas (AEF) are uncommon causes of gastrointestinal bleeding. Both surgical and endovascular options are described for the management of AEF. A hybrid approach is recommended in cases of recurrent AEF. Herein we present a patient with recurrent secondary AEF with severe hypotension, melaena, and hematemesis, who underwent embolization of the residual aortic stump with the parallel placement of two vascular plugs and onyx for control of the situation. Supplementary Information: The online version contains supplementary material available at 10.1007/s12055-022-01342-1.

Prevalence of Aortic Plaques in Cryptogenic Ischemic Stroke: Correlation to Vascular Risk Factors and Future Events.

Background and Purpose: Limited data is available regarding the prevalence of aortic plaques in cryptogenic ischemic strokes and its correlation with risk factors. Aim: To determine the prevalence of aortic plaques in patients with cryptogenic ischemic stroke and its association with vascular risk factors and future vascular events. Methodology: Patients with cryptogenic ischemic stroke/TIA evaluated with CT angiogram (CTA) were recruited. Aortic plaque thickness ≥4 mm, plaque ulceration, protruding components, and complex plaques were considered significant. Results: Of the 1,767 patients, 229 (12.9%) had cryptogenic ischemic stroke/transient ischemic attack (TIA). Of them, 36 (15.7%) patients were detected to have significant aortic plaques. The significant plaque group had a higher mean age (68.3 ± 8.3 vs 54.4 ± 13.2, P = 0.0005) and were more likely to have risk factors like hypertension (P = 0.025), coronary artery disease (CAD)(P = 0.015), and peripheral vascular disease (POVD) (P = 0.029). Plaque morphology showed plaques of ≥4 mm, ulcerated plaques, protruding components, and complex plaques in 14.8%, 5.6%, 3.1%, and 6.5% patients, respectively, which are predominantly located in the aortic arch (44%). At 1 year combined endpoint of stroke, TIA, and vascular death was significantly higher in the significant plaque group (19.4% vs 6.2%, P = 0.016). Advanced age (adjusted OR-1.11, 95% CI-1.07-1.17, P = <0.001) was identified as an independent risk factor for significant aortic plaques on multivariate analysis. Conclusions: Aortic plaques are an under-recognized cause of cryptogenic stroke. The significant risk factors in aortic plaque group highlight the importance of aggressive risk factor control for secondary stroke prevention.

Crossover based technique for data augmentation.

BACKGROUND AND OBJECTIVE: Medical image classification problems are frequently constrained by the availability of datasets. "Data augmentation" has come as a data enhancement and data enrichment solution to the challenge of limited data. Traditionally data augmentation techniques are based on linear and label preserving transformations; however, recent works have demonstrated that even non-linear, non-label preserving techniques can be unexpectedly effective. This paper proposes a non-linear data augmentation technique for the medical domain and explores its results. METHODS: This paper introduces "Crossover technique", a new data augmentation technique for Convolutional Neural Networks in Medical Image Classification problems. Our technique synthesizes a pair of samples by applying two-point crossover on the already available training dataset. By this technique, we create N new samples from N training samples. The proposed crossover based data augmentation technique, although non-label preserving, has performed significantly better in terms of increased accuracy and reduced loss for all the tested datasets over varied architectures. RESULTS: The proposed method was tested on three publicly available medical datasets with various network architectures. For the mini-MIAS database of mammograms, our method improved the accuracy by 1.47%, achieving 80.15% using VGG-16 architecture. Our method works fine for both gray-scale as well as RGB images, as on the PH2 database for Skin Cancer, it improved the accuracy by 3.57%, achieving 85.71% using VGG-19 architecture. In addition, our technique improved accuracy on the brain tumor dataset by 0.40%, achieving 97.97% using VGG-16 architecture. CONCLUSION: The proposed novel crossover technique for training the Convolutional Neural Network (CNN) is painless to implement by applying two-point crossover on two images to form new images. The method would go a long way in tackling the challenges of limited datasets and problems of class imbalances in medical image analysis. Our code is available at https://github.com/rishiraj-cs/Crossover-augmentation.