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Background and Purpose: Mechanical thrombectomy (MT) in ischemic stroke patients with poor prestroke conditions remains controversial. We aimed to analyze the frequency of previously disabled patients treated with MT in clinical practice, the safety and clinical response to MT of patients with preexisting disability, and the disabled patient characteristics associated with a better response to MT. Methods: We studied all consecutive patients with anterior circulation occlusion treated with MT from January 2017 to December 2019 included in the Codi Ictus Catalunya registry—a government-mandated, prospective, hospital-based data set. Prestroke disability was defined as modified Rankin Scale score 2 or 3. Functional outcome at 90 days was centrally assessed by a blinded evaluator of the Catalan Stroke Program. Favorable outcome (to return at least to prestroke modified Rankin Scale at 90 days) and safety and secondary outcomes were compared with patients without previous disability. Logistic regression analysis was used to assess the association between prestroke disability and outcomes and to identify a disabled patient profile with favorable outcome after MT. Results: Of 2487 patients included in the study, 409 (17.1%) had prestroke disability (313 modified Rankin Scale score 2 and 96 modified Rankin Scale score 3). After adjustment for covariates, prestroke disability was not associated with a lower chance of achieving favorable outcome at 90 days (24% versus 30%; odds ratio, 0.79 [0.57–1.08]), whereas it was independently associated with a higher risk of symptomatic intracranial hemorrhage (5% versus 3%; odds ratio, 2.04 [1.11–3.72]) and long-term mortality (31% versus 18%; odds ratio, 1.74 [1.27–2.39]) compared with patients without disability. Prestroke disabled patients without diabetes, Alberta Stroke Program Early CT Score >8 and National Institutes of Health Stroke Scale score Conclusions: Despite a higher mortality and risk of symptomatic intracranial hemorrhage, prestroke-disabled patients return as often as independent patients to their prestroke level of function, especially those nondiabetic patients with favorable early ischemic signs profile. These data support a potential benefit of MT in patients with previous mild or moderate disability after large anterior vessel occlusion stroke.

Objective Stereoelectroencephalography (SEEG) consists of the implantation of microelectrodes for the electrophysiological characterization of epileptogenic networks. To reduce a possible risk of intracranial bleeding by vessel rupture during the electrode implantation, the stereotactic trajectories must follow avascular corridors. The use of digital subtraction angiography (DSA) for vascular visualization during planning is controversial due to the additional risk related to this procedure. Here we evaluate the utility of this technique for planning when the neurosurgeon has it available together with gadolinium-enhanced T1-weighted magnetic resonance sequence (T1-Gd) and computed tomography angiography (CTA). Methods Twenty-two implantation plans for SEEG were initially done using T1-Gd imaging (251 trajectories). DSA was only used later during the revision process. In 6 patients CTA was available at this point as well. We quantified the position of the closest vessel to the trajectory in each of the imaging modalities. Results Two thirds of the trajectories that appeared vessel free in the T1-Gd or CTA presented vessels in their proximity, as shown by DSA. Those modifications only required small shifts of both the entry and target point, so the diagnostic aims were preserved. Conclusions T1-Gd and CTA, despite being the most commonly used techniques for SEEG planning, frequently fail to reveal vessels that are dangerously close to the trajectories. Higher-resolution vascular imaging techniques, such as DSA, can provide the neurosurgeon with crucial information about vascular anatomy, resulting in safer plans.

Spontaneous subarachnoid hemorrhage (SAH) long-term risk is not well known. Our aims are: describing long-term vascular event (VE) incidence rates in SAH survivors; describing VE: ischemic and/or hemorrhagic; identifying independent association of factors related to VE; and analyzing the usefulness of factors to increase predictive ability.A prospective cohort study of consecutive patients admitted to Hospital del Mar with a diagnosis of SAH (n = 566) between January 2007 and January 2020 was carried out. They were followed up until January 2021. The study endpoint was a new VE in the follow-up. We calculated both incidence rates and cumulative rates at 5 years. Cox regression survival models including vascular risk factors with and without specific data of SAH disease were developed. We analyzed ROC curves of all multivariate models.The analyzed cohort included 423 non-fatal SAH cases. Total patient-years were 2468.16 years. The average follow-up was 70.03 ± 43.14; range: 1-180 months. There were 49 VE detected in 47 patients, as 2 of them had more than 1 VE. Incidence rate was 0.020 events_per_patient/year, cumulative incidence at 5 years was 11.11%. The more frequent VE that we found were cerebrovascular (28/49), mainly ischemic (21/28). Disability after SAH and the presence of multiple aneurysms were independently associated with a VE risk and improved the predictive capacity of multivariate models (AUC 0.679 vs 0.764; p = 0.0062).We reported a low vascular risk after SAH. We have shown the usefulness of SAH factors to identify patients with a higher risk of VE.

IMPORTANCE: It is estimated that only 27% of patients with acute ischemic stroke and large vessel occlusion who undergo successful reperfusion after mechanical thrombectomy are disability free at 90 days. An incomplete microcirculatory reperfusion might contribute to these suboptimal clinical benefits. OBJECTIVE: To investigate whether treatment with adjunct intra-arterial alteplase after thrombectomy improves outcomes following reperfusion. DESIGN, SETTING, AND PARTICIPANTS: Phase 2b randomized, double-blind, placebo-controlled trial performed from December 2018 through May 2021 in 7 stroke centers in Catalonia, Spain. The study included 121 patients with large vessel occlusion acute ischemic stroke treated with thrombectomy within 24 hours after stroke onset and with an expanded Treatment in Cerebral Ischemia angiographic score of 2b50 to 3. INTERVENTIONS: Participants were randomized to receive intra-arterial alteplase (0.225 mg/kg; maximum dose, 22.5 mg) infused over 15 to 30 minutes (n = 61) or placebo (n = 52). MAIN OUTCOMES AND MEASURES: The primary outcome was the difference in proportion of patients achieving a score of 0 or 1 on the 90-day modified Rankin Scale (range, 0 [no symptoms] to 6 [death]) in all patients treated as randomized. Safety outcomes included rate of symptomatic intracranial hemorrhage and death. RESULTS: The study was terminated early for inability to maintain placebo availability and enrollment rate because of the COVID-19 pandemic. Of 1825 patients with acute ischemic stroke treated with thrombectomy at the 7 study sites, 748 (41%) patients fulfilled the angiographic criteria, 121 (7%) patients were randomized (mean age, 70.6 [SD, 13.7] years; 57 women [47%]), and 113 (6%) were treated as randomized. The proportion of participants with a modified Rankin Scale score of 0 or 1 at 90 days was 59.0% (36/61) with alteplase and 40.4% (21/52) with placebo (adjusted risk difference, 18.4%; 95% CI, 0.3%-36.4%; P = .047). The proportion of patients with symptomatic intracranial hemorrhage within 24 hours was 0% with alteplase and 3.8% with placebo (risk difference, −3.8%; 95% CI, −13.2% to 2.5%). Ninety-day mortality was 8% with alteplase and 15% with placebo (risk difference, −7.2%; 95% CI, −19.2% to 4.8%). CONCLUSIONS AND RELEVANCE: Among patients with large vessel occlusion acute ischemic stroke and successful reperfusion following thrombectomy, the use of adjunct intra-arterial alteplase compared with placebo resulted in a greater likelihood of excellent neurological outcome at 90 days. However, because of study limitations, these findings should be interpreted as preliminary and require replication. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03876119; EudraCT Number: 2018-002195-40

Rationale The potential value of rescue intraarterial thrombolysis in patients with large vessel occlusion stroke treated with mechanical thrombectomy has not been assessed in randomized trials. Aim The CHemical OptImization of Cerebral Embolectomy trial aims to establish whether rescue intraarterial thrombolysis is more effective than placebo in improving suboptimal reperfusion scores in patients with large vessel occlusion stroke treated with mechanical thrombectomy. Sample size estimates A sample size of 200 patients allocated 1:1 to intraarterial thrombolysis or intraarterial placebo will have >95% statistical power for achieving the primary outcome (5% in the control versus 60% in the treatment group) for a two-sided (5% alpha, and 5% lost to follow-up). Methods and design We conducted a multicenter, randomized, placebo-controlled, double blind, phase 2b trial. Eligible patients are 18 or older with symptomatic large vessel occlusion treated with mechanical thrombectomy resulting in a modified treatment in cerebral ischemia score 2b at end of the procedure. Patients will receive 20–30 min intraarterial infusion of recombinant tissue plasminogen activator or placebo (0.5 mg/ml, maximum dose limit 22.5 mg). Study outcome(s) The primary outcome is the proportion of patients with an improved modified treatment in cerebral ischemia score 10 min after the end of the study treatment. Secondary outcomes include the shift analysis of the modified Rankin Scale, the infarct expansion ratio, the proportion of excellent outcome (modified Rankin Scale 0–1), the proportion of infarct expansion, and the infarction volume. Mortality and symptomatic intracerebral bleeding will be assessed. Discussion The study will provide evidence whether rescue intraarterial thrombolysis improves brain reperfusion in patients with large vessel occlusion stroke and incomplete reperfusion (modified treatment in cerebral ischemia 2b) at the end of mechanical thrombectomy.

Background and purpose A well-known classification of dural arteriovenous fistulas (DAVFs) according to the patterns of venous drainage was described in 1977 by Djindjian, Merland et al. and later revised by Cognard, Merland et al. in 1995. They described 5 types of DAVFs assuming that the type of venous drainage is directly correlated with neurologic symptoms and in particular with hemorrhagic risk. We present a series of cases that combines type IV (DAVF with cortical venous drainage associated with venous ectasia) and type V (DAVF with spinal venous drainage), which we named type IV + V. Materials and methods A retrospective study between 2012 and 2020 in 2 Hospitals was performed on patients that met inclusion criteria for a diagnosis of this type of DAVF. Demographics, location, clinical presentation and outcomes of endovascular embolization were studied. Results Five (2,3%) patients out of 220 had a type IV + V DAVF. All cases had an aggressive presentation, either subarachnoid hemorrhage, myelopathy or both. All patients were treated with endovascular transarterial embolization achieving complete angiographic occlusion in one session and total remission of symptoms at 3 months. Conclusions This rare type of DAVF, combines two aggressive venous drainage patterns. For that reason, patients with type IV+V DAVF probably have a more aggressive natural history and worst outcome due to risk of intracranial and/or spinal hemorrhage and myelopathy, thus requiring urgent diagnostic and treatment. Larger studies are needed to better understand this type of DAVF.

Background and Purpose— Our aim was to describe variables associated with initial misdiagnosis of subarachnoid hemorrhage (SAH). We also analyzed the relationship of misdiagnosis with poor outcome and complications in good Hunt and Hess (HH) cases. Methods— In a prospective cohort of 401 patients with SAH, misdiagnosis was defined as failure to correctly identify, at first physician contact, a subsequently documented SAH; this meant no urgent radiological study and lumbar puncture was performed. Poor outcome was defined as modified Rankin Scale score 3 to 6 at 3-month follow-up. We recorded age, sex, hypertension, diabetes mellitus, current smoking, previous antithrombotic treatment, initial HH and radiological severity, presence of aneurysm, first therapeutic procedure, hydrocephalus, delayed cerebral ischemia (DCI), rebleeding, and procedure-related complications. Results— Misdiagnosis was confirmed in 104/401 (25.9%) patients, who also had a longer time-to-admission to hospital. Misdiagnosis was associated with less clinical and radiological severity, compared with a correct diagnosis; the 2 groups did not differ in age or cardiovascular risk factor profile. Poor outcome was registered in 167/401 patients (41.6%). Age, misdiagnosis, and greater clinical and radiological initial severity were independent predictors of poor outcome. In the 236 patients (58.8% of cohort) with HH 1–2, misdiagnosis was associated with poor outcome in univariate and multivariate analysis, respectively (odds ratio=3.89; 95% CI, 1.89–8.01). Delayed cerebral ischemia (odds ratio=2.47; 95% CI, 1.2–5.09) and procedure-related complications (odds ratio=2.27; 95% CI, 1.07–4.82) were independently associated with misdiagnosis. Conclusions— Misdiagnosis is an unresolved problem in SAH, and it is a missed opportunity for good outcome in patients with HH 1–2. The poor outcome is partially explained by a higher risk of delayed cerebral ischemia and procedure-related complications in misdiagnosed patients. There is a need to improve the diagnostic strategy in patients reporting only a headache (HH 1–2) after SAH.

ObjectiveTo describe short-term and 5-year rates of mortality and poor outcome in patients with spontaneous aneurysmal subarachnoid hemorrhage (aSAH) who received repair treatment.MethodsIn this prospective observational study, mortality and poor outcome (modified Rankin Scale score 3–6) were analyzed in 311 patients with aSAH at 3 months, 1 year, and 5 years follow-up. Sensitivity analysis was performed according to treatment modality. In-hospital and 5-year complications were analyzed.ResultsOf 476 consecutive patients with spontaneous subarachnoid hemorrhage, 347 patients (72.9%) had aSAH. Of these, 311 (89.6%) were treated (242 endovascular, 69 neurosurgical), with a mean follow-up of 43.4 months (range, 1 to 145). Three-month, 1-year, and 5-year mortality was 18.4%, 22.9%, and 29.0%, and poor outcome was observed in 42.3%, 36.0%, and 36.0%, respectively. Adjusted poor outcome was lower in endovascular than in neurosurgical treatment at 3 months (odds ratio [OR] 0.36 [95% confidence interval [CI] 0.18-0.74]), with an absolute difference of 15.8% (number needed to treat = 6.3), and at 1 year (OR = 0.40 [95% CI 0.20-0.81]), with an absolute difference of 15.9% (number needed to treat = 6.3). Complications did not differ between the 2 procedures. However, mechanical ventilation was less frequent with the endovascular technique (OR 0.67 [95% CI 0.54–0.84]).ConclusionsPatients with aSAH treated according to current guidelines had a short-term mortality of 18.4% and 5-year mortality of 29%. The majority (64.0%) of patients remained alive without disabilities at 5-year follow-up. Patients prioritized to endovascular treatment had better outcomes than those referred to neurosurgery because endovascular coiling was not feasible.

PurposeTo describe the efficacy and complications of treating cerebral aneurysms with the Flow Re-direction Endoluminal Device (FRED) and to identify predictors for aneurysm occlusion.MethodsA prospective observational registry including all consecutive aneurysms treated with FRED between December 2015 and July 2018 was designed in one therapeutic neuroangiography department. The primary endpoint for treatment efficacy was complete or near-complete occlusion (O’Kelly–Marotta (OKM) C–D), assessed by three-dimensional digital subtraction angiography. Major (all symptomatics) and minor complications were described and those with modified Rankin Scale scores 3–6 were considered clinically relevant. Univariate and multivariate analyses were performed to identify predictors of efficacy.ResultsA total of 185 aneurysms were analyzed in 150 patients (mean age 54.3±11.5 years). Mean follow-up was 18.99±11.32 months (range 0–43). Efficacy was evaluated in 156 (84.32%) cases: 132 (84.6%) had OKM C–D occlusion, 31/47 (66%) within the first year and 101/109 (92.7%) later on. Major complications were observed in 12 (6.5%) cases: three strokes (one transient ischemic accident, two minor strokes), six intra-stent thrombosis, and three with bleeding, but only one (0.5%) was clinically relevant. Minor complications (all asymptomatic) were observed in 10 (5.4%) cases: three shortening/repositioning of stent; two arterial dissection, two arterial occlusion, and three intra-stent stenosis. Independent predictors of occlusion were immediate OKM grade B–C–D (OR 4.01, 95% CI 1.51 to 10.62), single aneurysm (OR 3.29, 95% CI 1.05 to 10.32), and small size aneurysm (OR 4.74, 95% CI 1.57 to 14.30).ConclusionThe FRED stent fully complied with efficacy and safety requirements for treatment of intracranial aneurysms. Three predictors of aneurysm occlusion were identified.

Background and Purpose— According to the International Study of Unruptured Intracranial Aneurysms (ISUIA), anterior circulation (AC) aneurysms of Methods— Information about 932 patients newly diagnosed with intracranial aneurysms between November 1, 2006, and March 31, 2012, including aneurysm status at diagnosis, its location, size, and risk factors, was collected during the multicenter @neurIST project. For each location or location and size subgroup, the odds ratio (OR) of aneurysms being ruptured at diagnosis was calculated. Results— The OR for aneurysms to be discovered ruptured was significantly higher for AcoA (OR, 3.5 [95% confidence interval, 2.6–4.5]) and posterior circulation (OR, 2.6 [95% confidence interval, 2.1–3.3]) than for AC excluding AcoA (OR, 0.5 [95% confidence interval, 0.4–0.6]). Although a threshold of 7 mm has been suggested by ISUIA as a threshold for aggressive treatment, AcoA aneurysms Conclusions— We found that AC aneurysms are not a homogenous group. Aneurysms between 4 and 7 mm located in AcoA or distal anterior cerebral artery present similar rupture odds to posterior circulation aneurysms. Intervention should be recommended for this high-risk lesion group.

Background and Purpose— We sought to assess outcomes after endovascular treatment/therapy of acute ischemic stroke, overall and by subgroups, and looked for predictors of outcome. Methods— We used data from a mandatory, population-based registry that includes external monitoring of completeness, which assesses reperfusion therapies for consecutive patients with acute ischemic stroke since 2011. We described outcomes overall and by subgroups (age ≤ or >80 years; onset-to-groin puncture ≤ or >6 hours; anterior or posterior strokes; previous IV recombinant tissue-type plasminogen activator or isolated endovascular treatment/therapy; revascularization or no revascularization), and determined independent predictors of good outcome (modified Rankin Scale score ≤2) and mortality at 3 months by multivariate modeling. Results— We analyzed 536 patients, of whom 285 received previous IV recombinant tissue-type plasminogen activator. Overall, revascularization (modified Thrombolysis In Cerebral Infarction scores, 2b and 3) occurred in 73.9%, 5.6% developed symptomatic intracerebral hemorrhages, 43.3% achieved good functional outcome, and 22.2% were dead at 90 days. Adjusted comparisons by subgroups systematically favored revascularization (lower proportion of symptomatic intracerebral hemorrhages and death rates and higher proportion of good outcome). Multivariate analyses confirmed the independent protective effect of revascularization. Additionally, age >80 years, stroke severity, hypertension (deleterious), atrial fibrillation, and onset-to-groin puncture ≤6 hours (protective) also predicted good outcome, whereas lack of previous disability and anterior circulation strokes (protective) as well as and hypertension (deleterious) independently predicted mortality. Conclusions— This study reinforces the role of revascularization and time to treatment to achieve enhanced functional outcomes and identifies other clinical features that independently predict good/fatal outcome after endovascular treatment/therapy.

Les actes interventionnels endovasculaires au niveau intracerebral ont permis un traitement plus complet de certaines lesions, qui ont ete prises en charge conjointement avec les neurochirurgiens, les neuroradiologues interventionnistes et les radiotherapeutes. Par ailleurs, la neuroradiologie interventionnelle presente l'avantage de traiter les patients sans manipulation du cerveau, surtout dans les zones fonctionnelles a haut risque, et sans ouverture de la boite crânienne, permettant ainsi une duree d'hospitalisation souvent moindre que pour la chirurgie conventionnelle.

Morphological descriptors are practical and essential biomarkers for diagnosis and treatment selection for intracranial aneurysm management according to the current guidelines in use. Nevertheless, relatively little work has been dedicated to improve the three-dimensional quantification of aneurysmal morphology, to automate the analysis, and hence to reduce the inherent intra and interobserver variability of manual analysis. In this paper we propose a methodology for the automated isolation and morphological quantification of saccular intracranial aneurysms based on a 3D representation of the vascular anatomy.This methodology is based on the analysis of the vasculature skeleton's topology and the subsequent application of concepts from deformable cylinders. These are expanded inside the parent vessel to identify different regions and discriminate the aneurysm sac from the parent vessel wall. The method renders as output the surface representation of the isolated aneurysm sac, which can then be quantified automatically. The proposed method provides the means for identifying the aneurysm neck in a deterministic way. The results obtained by the method were assessed in two ways: they were compared to manual measurements obtained by three independent clinicians as normally done during diagnosis and to automated measurements from manually isolated aneurysms by three independent operators, nonclinicians, experts in vascular image analysis. All the measurements were obtained using in-house tools. The results were qualitatively and quantitatively compared for a set of the saccular intracranial aneurysms (n = 26).Measurements performed on a synthetic phantom showed that the automated measurements obtained from manually isolated aneurysms where the most accurate. The differences between the measurements obtained by the clinicians and the manually isolated sacs were statistically significant (neck width: p0.001, sac height: p = 0.002). When comparing clinicians' measurements to automatically isolated sacs, only the differences for the neck width were significant (neck width: p0.001, sac height: p = 0.95). However, the correlation and agreement between the measurements obtained from manually and automatically isolated aneurysms for the neck width: p = 0.43 and sac height: p = 0.95 where found.The proposed method allows the automated isolation of intracranial aneurysms, eliminating the interobserver variability. In average, the computational cost of the automated method (2 min 36 s) was similar to the time required by a manual operator (measurement by clinicians: 2 min 51 s, manual isolation: 2 min 21 s) but eliminating human interaction. The automated measurements are irrespective of the viewing angle, eliminating any bias or difference between the observer criteria. Finally, the qualitative assessment of the results showed acceptable agreement between manually and automatically isolated aneurysms.

Neurotoxicity from contrast media used in angiography is a rare complication from these procedures. The infrequency with which it is encountered makes it a diagnostic challenge. We present the case of a 51-year-old male who, 30 min after successful angiography for treatment of a right carotid-ophthalmic fusiform aneurysm with a stent, developed psychomotor agitation, disorientation, and progressive left faciobrachial hemiparesis (4/5). An emergency nonenhanced CT showed marked cortical enhancement and edema in the right cerebral hemisphere. Cortical enhancement is thought to be secondary to contrast extravasation due to disruption of the blood-brain barrier. Angiography was performed immediately, without any pathologic findings. After this procedure there was an increase in the left faciobrachial hemiparesis (3/5), right gaze deviation, Gerstmann syndrome, and left anosognosia and left homonymous hemianopsia. Endovenous dexamethasone and mannitol were initiated. Twenty-four hours later an MRI showed no signs of acute infarct, just gyriform signal increase in the right cerebral hemisphere on FLAIR and a decrease in the edema observed before. The patient had progressive improvement of his neurological deficit. A control MRI done 5 days later was normal. The patient recovered completely and was discharged. This rare entity should be kept in mind but diagnosed only when all other causes have been ruled out, because more important and frequent causes, such as acute infarct, must be excluded promptly.

Endovascular treatment of intracranial aneurysms is a minimally-invasive technique recognized as a valid alternative to surgical clipping. However, endovascular treatment can be associated to aneurysm recurrence, either due to coil compaction or aneurysm growth. The quantification of coil compaction or aneurysm growth is usually performed by manual measurements or visual inspection of images from consecutive follow-ups. Manual measurements permit to detect large global deformation but might have insufficient accuracy for detecting subtle or more local changes between images. Image inspection permits to detect a residual neck in the aneurysm but do not differentiate aneurysm growth from coil compaction. In this paper, we propose to quantify independently coil compaction and aneurysm growth using non-rigid image registration. Local changes of volume between images at successive time points are identified using the Jacobian of the non-rigid transformation. Two different non-rigid registration strategies are applied in order to explore the sensitivity of Jacobian-based volume changes against the registration method, FFD registration based on mutual information and Demons. This volume-variation measure has been applied to four patients of which a series of 3D Rotational Angiography (3DRA) images obtained at different controls separated from two months to two years were available. The evolution of coil and aneurysm volumes along the period has been obtained separately, which allows distinguishing between coil compaction and aneurysm growth. On the four cases studied in this paper, aneurysm recurrence was always associated to aneurysm growth, as opposed to strict coil compaction.

Although the incidence of ruptured cerebral aneurysms is relatively small, when rupture occurs, morbidity and mortality are exceptionally high. The understanding of the pathological and physiological forces driving aneurysmal pathogenesis and progression is crucial. In this paper we analyze the occurrence of mirror cerebral aneurysms in 8 patients and speculate on the effect of haemodynamics on the localization and course of the disease. By mirror cerebral aneurysms we indicate two aneurysms in the same patient and at the same location in the cerebral vasculature but symmetrically with respect to a sagittal plane. In particular we focus on cases of mirror cerebral aneurysms where only one of the two aneurysms presented subarachnoid hemorrhage (SAH). Anatomical information is extracted from 3D rotational angiography (3DRA) images and haemodynamic information is obtained through blood flow simulation in patientspecific anatomical models. The distribution of Wall Shear Stress (WSS) and the flow patterns through the vessels and inside the aneurysms are reported. By combining clinical observations on asymmetry of the cerebral vasculature and aneurysmal shape and size with computed information on blood flow patterns we explore the causes behind a specific localization and a different outcome of disease progression.

International audience; PURPOSE: To determine whether the blood flow abnormalities frequently associated with arteriovenous malformations (AVMs) can alter functional magnetic resonance (MR) imaging evaluation of language lateralization and whether reorganization of language function occurs in patients with brain AVMs. MATERIALS AND METHODS: Eleven patients with left-hemisphere brain AVMs and 10 age-matched control subjects were examined with 1.5-T blood oxygen level-dependent (BOLD) functional MR imaging. Verbal fluency, sentence repetition, and story listening tasks were performed. The functional MR imaging laterality index in the frontal and temporal lobes was defined as the (L - R)/(L + R) ratio, where L and R are the numbers of activated pixels in the left and right hemispheres, respectively. Statistical analyses were performed with Wilcoxon signed rank, Fisher exact, and Kruskal-Wallis tests. RESULTS: Control subjects had left-sided language dominance, although symmetric pixel counts were observed in the frontal lobes in two subjects and in the temporal lobes in one subject. Six patients had left-sided language dominance similar to that observed in control subjects. Five of these patients had AVMs outside frontal or temporal language areas, without flow abnormalities. Five patients had abnormally right-sided asymmetric indexes (below mean control subject value - 2 SDs), which suggested language reorganization (P