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.

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.

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/.

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.

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.

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.

Alterations in Resting-State Functional MRI Connectivity Related to Cognitive Changes in Intracranial Dural Arteriovenous Fistulas Before and After Embolization Treatment.

BACKGROUND: Cognitive decline is a non-hemorrhagic, major complication of intracranial dural arteriovenous fistula (DAVF), thought to be primarily related to venous hypertension. However, imaging features to predict cognitive decline are scanty in the literature. PURPOSE: To evaluate functional connectivity (FC) changes of resting-state networks (RSNs) in DAVF before and after treatment and its relation to cognitive impairment. STUDY TYPE: Prospective. SUBJECTS: DAVF subjects were screened for inclusion. Pre-embolization (N = 33, mean age 45.9 years, 29 males), 1 month post-embolization (N = 20, mean age 42.7 years, 19 males), and healthy controls (HC, N = 33, mean age 45.09 years, 27 males). FIELD STRENGTH/SEQUENCE: 3.0 T, resting-state functional magnetic resonance imaging (MRI), three-dimensional (3D) T1, T2 fast spin echo (FSE), diffusion weighted imaging (DWI), susceptibility weighted imaging (SWI), fluid-attenuated inversion recovery, and time of flight. ASSESSMENT: Data quality assessment was performed. FC analysis was done using group independent component analysis (ICA) and seed to voxel analysis. Neuropsychology (NP) scores of patients were compared with HC and correlated with FC changes. STATISTICAL TESTS: Voxel-wise parametric T-statistics for F-test was executed in FC analysis (p-FDR corrected <0.05). NP scores between DAVF group and HC group were compared using one-way analysis of variance with post hoc Bonferroni correction (P < 0.05). RESULTS: Both RSNs analysis methods showed reduced FC at the precuneus-posterior cingulate cortex (PC-PCC) of default mode network (DMN), anterior cingulate cortex (ACC) of the salience network (SN), and possible compensatory increased connectivity at the frontoparietal (FPN) and dorsal attention (DAN) networks. DAVF with low NP scores showed reduced FC at DMN and SN and minimal to absent connectivity at FPN and DAN. At post-embolization 1-month follow-up, improvement in FC at PC-PCC of DMN and ACC of SN were noted. DATA CONCLUSION: RS-fMRI in DAVF displayed FC changes that may be related to cognitive decline and its subsequent reversibility after treatment. FC changes at DMN, SN, FPN, and DAN were linked to cognitive decline and the corresponding NP scores. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 2.

Impaired intrinsic functional connectivity among medial temporal lobe and sub-regions related to memory deficits in intracranial dural arteriovenous fistula.

PURPOSE: The functional changes concerning memory deficits in dural arteriovenous fistula (dAVF) brain are inadequately understood. This study aimed to understand the functional connectivity alterations of brain regions widely affirmed for explicit and implicit memory functions in dAVF patients (DP) and look into the frequency effects of the altered functional networks. METHODS: Resting-state functional magnetic resonance imaging (rsfMRI) analysis was done in the memory-associated regions of 30 DP and 30 healthy controls (HC). Frequency decomposition was used to determine potential frequency-dependent functional connectivity changes. They underwent neuropsychological tests and were correlated with changes in memory networks compared with HC. RESULTS: The results showed weaker functional connectivity among the medial temporal lobe and sub-regions in DP suggestive of dysfunction of explicit and implicit memory functions, which corroborated with the positive correlation between memory scores and hippocampal-parahippocampal connectivity of DP, along with a significant group difference of lower memory and cognitive performance in DP assessed by neuropsychological tests. A frequency-dependent study of the altered rsFC revealed lower functional connectivity strength and impaired neural coupling manifested at some sub-band frequencies indicative of disturbed cortical rhythm in DP. CONCLUSION: This pilot study gives insights into significant intrinsic functional connectivity changes in the memory regions of the dAVF brain. The results may have clinical implications in the choice of interventional management of dAVF and can impact clinical decision making for realizable prevention of progressive memory impairment and irreversible brain damage in such patients.

Shunt Site Localization of Direct Carotid-Cavernous Fistula Using 3D Rotational Angiography-Utility of Broken-Rim Sign.

BACKGROUND: Direct carotid-cavernous fistulas (DCCF) develop due to breach in the integrity of the wall of the internal carotid artery, and its localization can sometimes be difficult due to rapid high flow shunts. We hypothesized that 3D rotational angiography could locate the fistula site accurately, where an interrupted rim of the carotid wall would be silhouetted against opacified vascular structures. This finding was described as a broken-rim sign, and in this study, we assessed the utility of this sign in the localization of the shunt point of DCCF. METHODS: Retrospective analysis of 15 cases of DCCF was performed, and the rent was characterized based on the broken-rim sign. Two observers independently evaluated the results and compared them against the intraoperative observations. RESULTS: The broken-rim sign was identified and correlated with the actual fistula site in 86.6% and 100% of patients by observers 1 and 2, respectively. The inter-rater agreement was 0.87 (P < 0.001). Misinterpretation was made in 2 patients by 1 observer, due to poor contrast opacification of the vascular structures secondary to very rapid shunting and mild movement artifacts. CONCLUSIONS: Our study highlights the role of 3D rotational angiogram and analysis of the carotid wall in the localization of the shunt site in DCCF. The broken-rim sign accurately points to the location of the fistula.

Volumetric T2-weighted MRI improves the diagnostic accuracy of spinal vascular malformations: comparative analysis with a conventional MR study.

BACKGROUND: To date, very little study of the importance of a volumetric T2-weighted MR sequence in the evaluation of spinal vascular malformations (SVMs) has been carried out. OBJECTIVE: To determine the utility and accuracy of a volumetric T2 MR sequence compared with conventional T2 in the diagnosis of SVMs. METHODS: Retrospective analysis of all patients who underwent spinal DSA for suspected SVMs was conducted. Conventional T2 and volumetric T2 MR images were analysed for the presence of flow voids and parenchymal changes, and SVMs were characterized. The sensitivity, specificity, and overall diagnostic accuracy of these MRI diagnoses were calculated. RESULTS: Of 89 subjects included in the final analysis, 70 patients had angiographically proved SVMs (38 patients with spinal cord arteriovenous malformations [SCAVM-intramedullary or perimedullary] and 32 cases of spinal dural arteriovenous fistula (SDAVF)) and the remaining 19 subjects were normal. The sensitivity and specificity for identification of SVMs were 98.1% and 90% for volumetric T2 sequences, compared with 82.8% and 89.4% for conventional T2 MRI, respectively. For characterization of spinal vascular lesions, volumetric MRI showed high sensitivity, specificity, and accuracy for SDAVF (100%, 90%, 97%, respectively) compared with conventional T2 MRI (71.8%, 89%, 79%, respectively). The positive likelihood ratio was high and negative likelihood ratio was zero for volumetric MRI evaluation of SDAVF, while these ratios were comparable between the two sequences for SCAVM. CONCLUSION: Volumetric T2 MRI is highly sensitive for the detection of SVMs, especially for SDAVF. Volumetric T2 MRI could be introduced into routine clinical practice in the screening of suspected SVMs.

Results of Endovascular-First Approach for Treatment of Scalp Arteriovenous Malformations and the Effect of Simplified Angiographic Classification in Therapeutic Decision-Making and Outcomes.

BACKGROUND: Scalp arteriovenous malformation (SAVM) is primarily treated by surgery and reports on endovascular treatment are scarce. We report the results of an endovascular-first approach in the treatment of SAVM. We also have proposed a simple dichotomized classification using the angiographically determined morphology findings and discussed its effect on therapeutic decision-making and outcomes. METHODS: A consecutive series of 25 patients with SAVM treated by initial or endovascular-only methods were included in the final analysis. The SAVM was categorized as a plexiform or fistulous type according to the angiographic morphology. The demographic data, treatment variables, and final clinical outcomes were analyzed and correlated with the proposed classification. RESULTS: Of the 25 patients, 21 were treated with n-butyl cyanoacrylate (n-BCA) and 3 with liquid ethylene vinyl alcohol. One patient had been treated initially with polyvinyl alcohol particles and later with n-BCA. Overall, complete or near complete obliteration (>90%) was achieved in 72%. Surgical excision was performed in 76%, most often after n-BCA embolization. Fistulous-type SAVMs required greater n-BCA concentrations (median, 33% vs. 20%; P = 0.024) and achieved greater rates of complete or near-complete obliteration (90% vs. 63%). Two patients with fistulous-type SAVMs treated with liquid ethylene vinyl alcohol showed complete resolution, and further treatment was not necessary. Overall, regardless of the embolic material used, the fistulous type demonstrated a significantly greater rate of complete obliteration (75% vs. 33%; P = 0.041) compared with plexiform type. CONCLUSION: High rates of complete and durable obliteration of SAVM are achievable with endovascular embolization. The proposed simplified classification is easy to implement and can aid in choosing the appropriate embolic agent and predicting the therapeutic outcome.

Extending Endovascular Embolization to Type A Spinal Perimedullary Arteriovenous Fistula Using Liquid Embolic Agent: Technical Nuances, Challenges and Initial Outcome.

BACKGROUND: The definitive treatment of perimedullary arteriovenous fistulas (PMAVFs) is warranted in view of the progressive neurologic decline noted with the conservative mode of management. The treatment options include microsurgical excision, endovascular embolization, or a multimodal approach. Because of the relatively larger size of the feeding arteries in type B and C PMAVFs, an endovascular approach is usually feasible. However, the endovascular treatment for type A lesions is technically challenging in view of near normal sized arterial feeders. Endovascular embolization using n-butyl cyanoacrylate is described; however, successful use of liquid embolic agents such as onyx or squid is not previously documented. CASE DESCRIPTION: The described 3 cases initially presented with insidious onset and gradually progressive paraparesis, paresthesia, and urinary symptoms. The imaging (magnetic resonance and digital subtraction angiography) revealed type A PMAVFs. The microcatheter could be successfully navigated close to the fistulous site, and complete obliteration of the fistula was achieved using ethylene vinyl alcohol copolymer (EVOH)-based liquid embolic agent, squid in all of our cases. The occlusion remained durable, and patients showed steady neurologic improvement in the follow-up period. CONCLUSIONS: Endovascular embolization of type A PMAVF using EVOH-based liquid embolic agent is feasible and could be considered as an effective alternative to surgery.

Recurring Thalamic Symptoms Due to Intracranial Dural Arteriovenous Fistula: Report of Unusual Case and Treatment Outcome.

BACKGROUND: Initial clinical presentation of dural arteriovenous fistula (DAVF) with predominantly thalamic symptoms is rare and has not been reported until now. CASE DESCRIPTION: A young child presenting with complaints of tinnitus and mild right hemiparesis was evaluated with an initial magnetic resonance imaging, which revealed a Borden type 2 DAVF in the right transverse sinus with retrograde venous drainage and cortical venous reflux. Flow-related small aneurysms were also noted in the left basal vein of Rosenthal (BVR). Two days later, his motor power deteriorated and he developed right hemisensory loss and severe thalamic pain. Aphasia was atypical and mimicked the transcortical type. Repeat imaging revealed expanding thrombosed aneurysm of BVR with mass effect and edema on thalamocapsular region. Initial antiedema measures reversed the neurologic deficits; however, they recurred, necessitating an urgent endovascular intervention. Angiogram revealed an extensive high-flow DAVF in the right transverse-sigmoid sinus and torcula with preferential retrograde venous drainage into deep veins and left BVR. He underwent staged embolization of DAVF, resulting in significant obliteration of shunt. Neurologic deficits improved in the postoperative period, and the patient remained clinically asymptomatic at 6 months of follow-up. CONCLUSIONS: DAVF presenting with recurrent predominantly thalamic symptoms is rare. Atypical transcortical aphasia rather than fluent aphasia is an unusual clinical manifestation of thalamic pathology and could result from the involvement of specific thalamic nuclei. Preferential high flow into BVR in the presence of venous anomalies could potentially induce architectural weakness of the venous wall and precipitate aneurysm formation. Embolization of the DAVF can potentially reverse this unusual neurologic condition.

Dwell Time of Stentriever Influences Complete Revascularization and First-Pass TICI 3 Revascularization in Acute Large Vessel Occlusive Stroke.

OBJECTIVE: In acute ischemic stroke with large vessel occlusion, the interaction between the clot retriever and the stent is critical for achieving successful recanalization. The ideal time of stent deployment (dwell time [DT]) to improve revascularization is currently unknown. We systematically analyzed the effect of different DT on final angiographic and clinical outcomes of patients who underwent mechanical thrombectomy. METHODS: The DT was progressively increased from 3 minutes to 5 minutes and then 8 minutes during the study period. The effect of DT on recanalization attempts, successful angiographic outcome (thrombolysis in cerebral ischemia [TICI] 2b or TICI 3), total revascularization time, and immediate and 3-month clinical outcomes were evaluated. The DT of 3 minutes and 5 minutes (DT3-5) was compared against DT of 8 minutes (DT8). RESULTS: Forty patients were included in the analysis. Good angiographic outcome was observed in 94.1% of patients in the DT8 cohort with an average attempt of 1.2 compared with 78.3% with average attempts of 2.0 in other group. Single-pass good recanalization (TICI 2b or 3) and single-pass complete revascularization (TICI3) was significantly higher in the DT group compared with the DT3-5 group (82.4% vs. 43.5% [P = 0.013] and 42.9% vs. 8.7% [P = 0.003], respectively). A favorable trend toward a reduced overall procedural time (34.59 vs. 55.59 minutes) was observed, but was not statistically significant (P = 0.15). CONCLUSIONS: Mild prolongation of DT to 8 minutes improves revascularization outcome with fewer attempts, possibly because of better clot-stent interaction.

Isolated Subcallosal Artery Infarction Secondary to Localized Cerebral Vasospasm of Anterior Communicating Artery Complex Following Subarachnoid Hemorrhage.

BACKGROUND: Subcallosal artery (ScA) infarction is a well-recognized but uncommon complication of surgical treatment of anterior communicating artery aneurysms. CASE DESCRIPTION: An elderly man presented with massive subarachnoid hemorrhage due to left posterior communicating artery aneurysm with thick clots in the anterior interhemispheric fissure. The aneurysm was coiled with balloon protection, and later, on the fifth day of ictus, the patient became acutely confused and developed memory disturbances. Magnetic resonance evaluation revealed typical infarcts in the anterior subcallosal region and fornix, confirming ScA infarction. Retrospective analysis of follow-up angiograms revealed focal isolated spasm of the anterior communicating artery artery and ScA, responding to intra-arterial milrinone infusion that was administered in view of neurologic worsening and clinical suspicion of cerebral vasospasm. CONCLUSION: Our case demonstrates a rare case of isolated ScA infarction induced by a local vasospasm and highlights the importance of its recognition. An early identification and intervention could potentially halt irreparable cerebral injury.