Moving From CT to MRI Paradigm in Acute Ischemic Stroke: Feasibility, Effects on Stroke Diagnosis and Long-Term Outcomes.

BACKGROUND: The relative value of computed tomography (CT) and magnetic resonance imaging (MRI) in acute ischemic stroke (AIS) is debated. In May 2018, our center transitioned from using CT to MRI as first-line imaging for AIS. This retrospective study aims to assess the effects of this paradigm change on diagnosis and disability outcomes. METHODS: We compared all consecutive patients with confirmed diagnosis of AIS admitted to our center during the MRI-period (May 2018-August 2022) and an identical number of patients from the preceding CT-period (December 2012-April 2018). Univariable and multivariable analyses were performed to evaluate outcomes, including the number and delay of imaging exams, the rate of missed strokes, stroke mimics treated with thrombolysis, undetermined stroke mechanisms, length of hospitalization, and 3-month disability. RESULTS: The median age of the 2972 included patients was 76 years (interquartile range, 65-84), and 46% were female. In the MRI-period, 80% underwent MRI as first acute imaging. The proportion of patients requiring a second acute imaging modality for diagnostic ± revascularization reasons increased from 2.1% to 5% (Punadj <0.05), but it decreased in the subacute phase from 79.0% to 60.1% (Padj <0.05). In thrombolysis candidates, there was a 2-minute increase in door-to-imaging delay (Padj <0.05). The rates of initially missed AIS diagnosis was similar (3.8% versus 4.4%, Padj=0.32) and thrombolysis in stroke mimics decreased by half (8.6% versus 4.3%; Padj <0.05). Rates of unidentified stroke mechanism at hospital discharge were similar (22.8% versus 28.1%; Padj=0.99). The length of hospitalization decreased from 9 (interquartile range, 6-14) to 7 (interquartile range, 4-12) days (Padj=0.62). Disability at 3 months was similar (common adjusted odds ratio for favorable Rankin shift, 0.98 [95% CI, 0.71-1.36]; Padj=0.91), as well as mortality and symptomatic intracranial hemorrhage. CONCLUSIONS: A paradigm shift from CT to MRI as first-line imaging for AIS seems feasible in a comprehensive stroke center, with a minimally increased delay to imaging in thrombolysis candidates. MRI was associated with reduced thrombolysis rates of stroke mimics and subacute neuroimaging needs.

Role of Cerebral Imaging on Diagnosis and Management in Patients With Suspected Infective Endocarditis.

BACKGROUND: Cerebral embolic events (CEEs) are common complications of infective endocarditis (IE), and their presence can modify diagnosis and therapeutic plans. The aim of the present study was to assess the role of cerebral imaging (Cer-Im) on diagnosis and management of patients with suspected IE. METHODS: This study was conducted at the Lausanne University Hospital, Lausanne, Switzerland, from January 2014 to June 2022. CEEs and IE were defined according to modified Duke criteria of the European Society of Cardiology (ESC) guidelines. RESULTS: Among 573 patients with IE suspicion and Cer-Im, 239 (42%) patients had neurological symptoms. At least 1 CEE was found in 254 (44%) episodes. Based on Cer-Im findings, episodes were reclassified from rejected to possible or from possible to definite IE in 3 (1%) and 25 (4%) patients, respectively (0% and 2% in asymptomatic patients, respectively). Among the 330 patients with possible or definite IE, at least 1 CEE was found in 187 (57%) episodes. A new surgical indication (in association with left-side vegetation >10 mm) was established in 74/330 (22%) IE patients and 30/155 (19%) asymptomatic IE patients, respectively. CONCLUSIONS: Cer-Im in asymptomatic patients with IE suspicion showed limited potential for improving the diagnosis of IE. In contrast, performing Cer-Im in asymptomatic patients with IE may be useful for decision making, because Cer-Im findings led to the establishment of new operative indication for valvular surgery in one fifth of patients according to ESC guidelines.

A severe case of neuroleukemiosis caused by B cell chronic lymphocytic leukemia, presenting as mononeuritis multiplex.

AIMS: To report an exceptional case of nerve infiltration by an otherwise benign chronic B cell leukemia, inducing severe mononeuritis multiplex. METHODS: The patient underwent extensive evaluation, including nerve conduction study and myography, brain and plexus MRI, and nerve biopsy. RESULTS: The clinical and electrophysiological diagnosis was a mononeuritis multiplex with severe motor and sensory involvement; only the nerve biopsy allowed definite diagnosis and introduction of chemotherapy, leading to resolution of sensory deficit and progressive motor improvement. DISCUSSION: Neuroleukemiosis caused by chronic lymphoid leukemia is an exceptional diagnosis. The presence of other possible causes like cryoglobulinemia could induce avoidance of nerve biopsy thus undertreating patient, since steroid treatment is not expected to be efficient on lymphocytic proliferation. Our case stretches the importance of nerve biopsy and raises neuromuscular specialist's awareness of this rare entity.

MRI software for diffusion-perfusion mismatch analysis may impact on patients' selection and clinical outcome.

OBJECTIVE: Impact of different MR perfusion software on selection and outcome of patients with acute ischemic stroke (AIS) and large vessel occlusion (LVO) treated by endovascular thrombectomy (EVT) is unclear. We aimed at comparing two commercial MRI software, semi-automated with unadjusted (method A) and adjusted mask (method B), and fully automated (method C) in this setting. METHODS: MRI from 144 consecutive AIS patients with anterior circulation LVO was retrospectively analysed. All diffusion- and perfusion-weighted images (DWI-PWI) were post-processed with the three methods using standard thresholds. Concordance for core and hypoperfusion volumes was assessed with Lin's test. Clinical outcome was compared between groups in patients who underwent successful EVT in the early and late time window. RESULTS: Mean core volume was higher and mean hypoperfusion volume was lower in method C than in methods A and B. In the early time window, methods A and B found fewer patients with a mismatch ratio ≤ 1.2 than method C (1/67 [1.5%] vs. 12/67 [17.9%], p = 0.0013). In the late time window, methods A and B found fewer patients with a mismatch ratio < 1.8 than method C (3/46 [6.5%] and 2/46 [4.3%] vs. 18/46 [39.1%], p ≤ 0.0002). More patients with functional independence at 3 months would not have been treated using method C versus methods A and B in the early (p = 0.0063) and late (p ≤ 0.011) time window. CONCLUSIONS: MRI software for DWI-PWI analysis may influence patients' selection before EVT and clinical outcome. KEY POINTS: • Method C detects fewer patients with favourable mismatch profile. • Method C might underselect more patients with functional independence at 3 months. • Software used before thrombectomy may influence patients' outcome.

Mechanical Thrombectomy in Perioperative Strokes: A Case-Control Study.

BACKGROUND AND PURPOSE: Perioperative strokes (POS) are rare but serious complications for which mechanical thrombectomy could be beneficial. We aimed to compare the technical results and patients outcomes in a population of POS versus non-POS (nPOS) treated by mechanical thrombectomy. METHODS: From 2010 to 2017, 25 patients with POS (ie, acute ischemic stroke occurring during or within 30 days after a procedure) who underwent mechanical thrombectomy (POS group) were enrolled and paired with 50 consecutive patients with nPOS (control group), based on the occlusion's site, National Institute of Health Stroke Scale, and age. RESULTS: Respectively, mean age was 68.3±16.6 versus 67.2±16.6 years (P=0.70), and median National Institute of Health Stroke Scale score at admission was 20 (interquartile range, 15-25) versus 19 (interquartile range, 17-25; P=0.79). Good clinical outcome (modified Rankin Scale score of 0-2 at 3 months) was achieved by 33.3% (POS) versus 56.5% (nPOS) of patients (P=0.055). Successful reperfusion (modified Thrombolysis In Cerebral Infarction score of ≥2b) was obtained in 76% (POS) versus 86% (nPOS) of cases (P=0.22). Mortality at 3 months was 33.3% in the POS group versus 4.2% (nPOS) (P=0.002). The rate of major procedural complications was 4% (POS) versus 6% (nPOS); none were lethal. Average time from symptoms' onset to reperfusion was 4.9 hours (±2.0) in POS versus 5.2 hours (±2.6). CONCLUSIONS: Successful reperfusion seems accessible in POS within a reasonable amount of time and with a good level of safety. However, favorable outcome was achieved with a lower rate than in nPOS, owing to a higher mortality rate.

Early Rebleeding after Brain Arteriovenous Malformation Rupture, Clinical Impact and Predictive Factors: A Monocentric Retrospective Cohort Study.

BACKGROUND: Brain arteriovenous malformations (BAVMs) are a leading cause of intracranial hemorrhage in young adults. This study aimed to identify individual predictive factors of early rebleeding after BAVM rupture and determine its impact on prognosis. METHODS: Early rebleeding was defined as a spontaneous intracranial hemorrhage within 30 days of BAVM rupture in patients with nonobliterated BAVMs. One hundred fifty one patients with 158 BAVM hemorrhagic events admitted to a tertiary care center during 14 years were included. Univariate followed by multivariate logistic regression was performed to assess the impact of early rebleeding on in-hospital mortality and modified Rankin Scale (mRS) score beyond 3 months and to identify independent predictors of early rebleeding. RESULTS: Eight early rebleeding events were observed, 6 of which occurred during the first 7 days. Early rebleeding was independently and significantly associated with poor outcome (mRS ≥3 beyond 3 months, p = 0.004) but not with in-hospital mortality (p = 0.9). Distal flow-related aneurysms (p = 0.009) and altered consciousness with a Glasgow coma scale score of 3 (p = 0.01) were independently associated with early rebleeding. CONCLUSIONS: Early rebleeding is a severe complication that can occur after BAVM-related hemorrhage. Distal flow-related aneurysms and initial altered consciousness are associated with early rebleeding.

Susceptibility-weighted angiography for the detection of high-flow intracranial vascular lesions: preliminary study.

OBJECTIVES: Susceptibility-weighted magnetic resonance imaging (MRI) sequences may demonstrate various signal intensities of draining veins in cases of high-flow vascular malformation (HFVM), including arteriovenous malformation (AVM) and dural arteriovenous fistula (dAVF). Our objective was to evaluate susceptibility-weighted angiography (SWAN) for the detection of HFVM. METHODS: Fifty-eight consecutive patients with a suspected intracranial vascular malformation were explored with SWAN and post-contrast MRI sequences at 3 T. The diagnosis of slow-flow vascular malformation (SFVM), including developmental venous anomaly (DVA) or brain capillary telangiectasia (BCT), was based on MRI. Patients with suspected HFVM underwent digital subtraction angiography (DSA). SWAN images were analysed by three blinded readers according to a three-point scale of the venous signal. RESULTS: Thirty-one patients presented 35 SFVM (26 DVA and 9 BCT) that systematically appeared hypointense on SWAN images. In patients with atypical MRI findings, DSA revealed one patient with an atypical DVA and 26 patients with HFVM (22 AVM and 4 dAVF). SWAN revealed at least one venous hyperintensity in all patients with HFVM. Agreement between readers was excellent. CONCLUSIONS: SWAN appears reliable for characterising blood flow dynamics in brain veins. In clinical practice, SWAN can routinely rule out HFVM in patients with atypical brain veins.

Flow diverters at and beyond the level of the circle of willis for the treatment of intracranial aneurysms.

BACKGROUND AND PURPOSE: Flow Diverters (FD) are a new emerging therapy for intracranial aneurysms. Initial reports focused on the treatment of proximally located aneurysms. We report our experience with FDs in the treatment of aneurysms at and beyond the circle of Willis. METHODS: We treated 30 aneurysms at and beyond the circle of Willis with FDs (silk and pipeline). Aneurysms were treated with FDs alone in 73.3% (22/30) and with FDs and coils in 23.3% (7/30). One procedure was converted in parent vessel occlusion. RESULTS: Thirty aneurysms (21/30, 70.0% saccular; 7/30, 23.3% fusiform; 2/30, 6.7% blister-like; sizes 1.2-19.6, mean 6.8 mm) were treated in 26 patients (17 women, 9 men; mean age, 49 years) during 27 procedures. Access site complication was noted in 3.7% (1/27). Reversible neurological complications were noted in 7.4% (2/27), permanent neurological complication in 3.7% (1/27). There was no mortality. No aneurysms bled or rebled after treatment. Aneurysms treated with FDs alone were significantly smaller than those treated with FDs and coils (5.7 and 10.0 mm, respectively; P=0.0174). Immediate angiographic occlusion was achieved in 18.2% (4/22) with FDs alone, in 0.0% (0/7) with FDs and coils. Twenty-four aneurysms (80.0%) had been followed (mean, 13 months). Fifteen of 19 aneurysms (78.9%) treated with FDs against 4 of 4 of aneurysms (100%) treated with FDs and coils were occluded. There was no angiographic recurrence of initially totally occluded aneurysms. CONCLUSIONS: Aneurysms at and beyond the circle of Willis are amenable to selective treatment with FDs.

Intracranial aneurysm coiling with PGLA-coated coils versus bare platinum coils: long-term anatomic follow-up.

INTRODUCTION: The purpose of this study is to compare the long-term (≥12 months) angiographic follow-up of aneurysms treated with polymer polyglycolic-lactic acid (PGLA)-coated coils versus bare platinum coils. METHODS: Long-term angiographic follow-up results of 90 aneurysms treated exclusively with PGLA-coated coils were retrospectively analyzed and compared to those of 158 aneurysms treated exclusively with bare platinum coils. RESULTS: There were 32 ruptured aneurysms (35.5%) in the PGLA-coated coil group and 62 (39.2%) in the bare platinum coil group. The mean angiographic follow-up was 29 months in the PGLA-coated coil group versus 27 months in the bare platinum coil group (P = 0.2297). The mean time to angiographic recurrence was 14 months in the PGLA-coated coil group versus 18 months in the bare platinum coil group (P = 0.1088). Recurrence rates were 35.6% (32/90) and 31.0% (49/158) in the PGLA-coated coil and bare platinum coil groups, respectively (P = 0.4837). The major recurrence justifying retreatment was 5.6% (5/90) in the PGLA-coated coil group versus 6.7% (10/158) in the bare platinum coil group (P = 1.000). CONCLUSION: PGLA-coated coils provided no better long-term recanalization rates than bare platinum coils.

Evaluation of stent visibility by flat panel detector CT in patients treated for intracranial aneurysms.

INTRODUCTION: This study aimed to evaluate the visibility of stents using high-resolution computed tomography (CT) acquisitions acquired with flat panel detector (XperCT, Allura series, Philips Healthcare, The Netherlands) for endovascular treatment of intracranial aneurysms. METHODS: On a 24-month period, 48 patients endovascularly treated by coiling and stenting (59 stents) for intracranial aneurysms were explored by flat panel detector CT technique. A sequence of 620 2D images was acquired over an angle of 240° using a 1,024 × 1,024 pixel matrix detector within a 48-cm field of view. The images were retrospectively analyzed independently by two neuroradiologists. Evaluation criteria were percentage of visualization of the stents and stent deployment (kinking or unsatisfactory deployment of the stent). RESULTS: Evaluation of the stent was feasible for all the patients. Stent visibility by XperCT was overall estimated at 76% of the stent length. Difficulties to analyze the stents were related to coil artifacts but not to packing density or aneurysm location. Stent length visualization was higher when the acquisition was performed before additional coiling (P < 0.0001). Mild kinking/misdeployment was noticed in 22% of the cases. CONCLUSION: XperCT technique provides multiplanar and 3D reconstructions that allows for a satisfying visualization of intracranial stents. This CT-like acquisition should be performed after the stent deployment and before coiling, in order to obtain better stent visualization.

Intravenous flat-detector CT angiography in acute ischemic stroke management.

INTRODUCTION: In the settings of stroke, a non-invasive high-resolution imaging modality to visualize the arterial intracranial circulation in the interventional lab is a helpful mean to plan the endovascular recanalization procedure. We report our initial experience with intravenously enhanced flat-detector CT (IV FDCT) technology in the detection of obstructed intracranial arteries. METHODS: Fourteen consecutive patients elected for endovascular stroke therapy underwent IV FDCT. The scans were intravenously enhanced and acquired in accordance with the previously calculated bolus arrival time. Images were processed on a commercially available workstation for reconstructions and 3D manipulation. Occlusion level and clot length, the quality of collateral vessels, and the patency of anterior and posterior communicating arteries were assessed. RESULTS: IV FDCT was performed successfully in all the cases and allowed for clot location and length visualization, assessment of communicating arteries patency, and evaluation of vessel collateral grade. Information obtained from this technique was considered useful for patients treated by endovascular approach. Retrospective review of the images by two independent readers was considered accurate and reproducible. CONCLUSIONS: IV FDCT technology provided accurate delineation of obstructed vessel segments in acute ischemic stroke disease. It gave a significant help in the interventional strategy. This new technology available in the operating room might provide a valuable tool in emerging endovascular stroke therapy.

Access to the ophthalmic artery by retrograde approach through the posterior communicating artery for intra-arterial chemotherapy of retinoblastoma.

Intra-arterial infusion of chemotherapy into the ophthalmic artery for treatment of retinoblastoma has been realized after catheterization of the internal carotid and temporary balloon occlusion beyond the orifice of the ophthalmic artery, or more recently after superselective canulation of the ophthalmic artery by a microcatheter. The superselective catheterization of the ophthalmic artery could be cumbersome because of the implantation of the ostium on the carotid siphon or because of the tortuosity of the carotid siphon. We report our experience of using a retrograde approach through the posterior communicating artery that allows a more direct angle of access to the origin of the ophthalmic artery.

Medina® Embolization Device for the Treatment of Intracranial Aneurysms: Safety and Angiographic Effectiveness at 6 Months.

BACKGROUND: The Medina Embolization Device (MED) is a new concept device that combines the design of a detachable coil and the one of an intrasaccular flow disruption device. OBJECTIVE: To evaluate the feasibility, safety, and 6- to 9-mo effectiveness of this new device for the treatment of intracranial wide-necked aneurysms. METHODS: Twelve patients (10 females, mean age = 56 yr) with 13 wide-necked intracranial aneurysms (3 ruptured; 10 unruptured) were treated by means of the MED from January 2015 to October 2015. In 15% of the cases, MEDs were used in a standalone fashion; in 85% of the cases, additional regular coils were used. Adjunctive compliant balloon was used in 4 of 13 cases (31%). Procedure-related complications were systematically recorded; discharge and 6- to 9-mo follow-up modified Rankin Scale was assessed. Angiographic follow-up was performed with a mean delay of 5.5 ± 1.7 mo. Occlusion rate was evaluated in postprocedure and at midterm follow-up using the Roy-Raymond scale. RESULTS: The deployment of the MED was feasible in all cases. No perforation was recorded. One case of thromboembolic complication was observed in a ruptured anterior communicating artery aneurysm, without any clinical consequence at follow-up. Grade A occlusion rate was 61.5% in postprocedure and 83% at 6-mo follow-up. Two cases (17%) of recanalization were documented angiographically. CONCLUSION: The MED is a new generation device combining the design of a detachable coil and an intrasaccular flow disruption device. According to our early experience, this device is safe and provides a satisfactory occlusion rate at angiographic follow-up of 6 mo.

Single-Center Experience Using the 3MAX Reperfusion Catheter for the Treatment of Acute Ischemic Stroke with Distal Arterial Occlusions.

PURPOSE: Most recent guidelines recommend the use of stent retriever devices in endovascular treatment of acute ischemic stroke with large vessel occlusion (LVO). Recently published data reported convincing results with thromboaspiration devices such as the Penumbra System (Penumbra, Alameda, CA, USA) combined with supple reperfusion catheters by using the ADAPT (A Direct Aspiration First-Pass Thrombectomy) technique. The aim of this study was to report our initial experience with the 3MAX (3.8 F) reperfusion catheter for the recanalization of distal intracranial arteries. METHODS: From August 2015 to December 2016, 32 consecutive patients (16 females, 50%; mean age = 67.4 ± 18.7 years, range: 22-91) for 38 distal occlusions underwent mechanical thrombectomy (MT) by thromboaspiration using the 3MAX. Median NIHSS score at admission was 14 (IQR: 9-19). Distal occlusions were distributed as follows: M2 (n: 23), M3 (n: 6), P1 (n: 3), P2 (n: 2), P3 (n: 2), A3 segment (n: 1) and superior cerebellar artery (n: 1). RESULTS: In 1/38 (2.6%) target artery, the 3MAX could not be navigated. Of the 37 (59.5%) remaining arteries, 22 were successfully reperfused (TICI 2b/3) after ADAPT with the 3MAX alone. Additional stent retriever thrombectomy allowed a 76.3% final reperfusion rate. Good functional outcome (mRS ≤2) was obtained in 45.5% of patients at 3 months. Three (9.4%) 3MAX-related complications occurred: 2 emboli to new territory (ENT) and one vascular perforation. CONCLUSIONS: The 3MAX is well-navigable in distal arteries making it useful as a frontline technique. However, the reperfusion rate with the 3MAX catheter alone seems lower than the ones reported with stent retrievers for such distal occlusions.

TransForm occlusion balloon catheter for the treatment of intracranial aneurysms, initial experience.

INTRODUCTION: The technique of balloon remodeling allows the endovascular treatment of wide-neck intracranial aneurysms. For many years the only available devices were the Hyperform and the Hyperglide balloon catheters. Recently, other companies have developed newer devices, single or dual-lumen. We present our initial experience with the TransForm occlusion balloon catheter for the treatment of intracranial aneurysms. METHODS: We retrospectively analysed from our prospectively gathered aneurysm database all aneurysms that were treated with balloon remodelling using TransForm occlusion balloon catheters from January 2013 to February 2014. We assessed patient demographics, morphological features of the aneurysms, procedure feasibility, technical and clinical complications. RESULTS: Thirty-three patients harbouring 36 intracranial saccular aneurysms were treated during 33 procedures. Clinical finding were: 15 incidental discovery, 13 subarachnoid haemorrhage (SAH), five aneurysms with mass effect, one ruptured aneurysm with SAH and mass effect, one recanalisation and one intraparenchymal haematoma. Thirty-five aneurysms were in the anterior and one in the posterior circulation. Mean dome and neck size were, respectively, 5.8 mm and 3.6 mm. Twenty-three aneurysms were treated with TransForm C and 13 with TransForm SC. We had two procedural thromboembolic complications, without permanent clinical events. No early rebleeding occurred. CONCLUSIONS: In our small series, the TransForm occlusion balloon catheter seems to be safe and effective for the treatment of intracranial aneurysms, in ruptured and unruptured cases.

Multimodal angiographic assessment of cerebral arteriovenous malformations: a pilot study.

PURPOSE: We describe our protocol of three-dimensional (3D) Roadmap intracranial navigation and image fusion for analysis of the angioarchitecture and endovascular treatment of brain arteriovenous malformations (AVMs). METHODS: We performed superselective catheterization of brain AVMs feeders under 3D-Roadmap navigation. Angiograms of each catheterized artery on two registered orthogonal views were transferred to the imaging workstations, and dedicated postprocessing imaging software allowed automated multiple overlays of the arterial supply of the AVM superselective acquisitions on the global angiogram in angiographic or 3D views and on coregistered MRI datasets. RESULTS: 11 untreated brain AVMs (4 with hemorrhagic presentation) were explored. The superselective acquisitions were performed under 3D-Roadmap navigation in 74 arteries, for a total of 79 targeted arteries. Imaging analysis was available at table side or postoperatively for discussion of the therapeutic strategy. No complications occurred during superselective catheterization. The accuracy of the coregistration of angiogram and MRI was submillimetric after automated mutual information coregistration, with manual re-registration by the physicians. CONCLUSIONS: Superselective angiograms acquired under 3D-Roadmap navigation can be postprocessed with multiple overlays. The fluoroscopic navigation under 3D-Roadmapping and the coregistration of 3D rotational angiography, selective angiography, and 3D MR datasets appears reliable with millimeter accuracy, and could be implemented in the critical brain AVM embolization setting to allow refined analysis of AVM angioarchitecture.

Angiographic factors influencing the success of endovascular treatment of arteriovenous malformations involving the corpus callosum.

OBJECTIVE: Arteriovenous malformations (AVMs) of the corpus callosum are rare lesions, accounting for 9-11% of brain AVMs. Microsurgical resection of such lesions is difficult because of their deep location, and also because of possible neuropsychological disasters resulting from extended callosal resection. The introduction of endovascular and radiation therapies has fundamentally changed the outcome of these lesions. METHODS: We prospectively collected clinical and angiographic data on cerebral AVMs from 1995. We reviewed data from patients treated for an AVM of the corpus callosum and identified the factors influencing the endovascular approach of such lesions. RESULTS: 38 patients (mean age 31 years) were consecutively treated by endovascular techniques. 78.9% (30 cases) of patients presented with intracranial hemorrhage. 15 AVMs (39.5%) were anterior, 18 (47.4%) were posterior, and five (13.1%) were holocallosal. The Spetzler-Martin grade was I in two cases (5.2%), II in 20 cases (52.6%), III in nine cases (23.7%), IV in six cases (15.8%), and V in one case (2.6%). The nidus was compact in 19 cases (50%), diffuse in 13 (34.2%), and multifocal in six (15.8%). Both anterior and posterior circulation branches fed 14 nidi (36.8%). Venous drainage was superficial in three cases (7.9%), deep in 28 (73.7%), and both in seven cases (18.4%). 104 sessions were performed, with a procedural complication rate of 6.7%. Mean follow-up was 43.6 months, with the last modified Rankin Scale score <3 in 33 cases (86.8%). 22 patients (57.9%) were totally cured. Univariate analysis of factors influencing the success of endovascular treatment showed that Spetzler-Martin grade ≥3 (p=0.046), nidus >30 mm (p=0.02), extension in an eloquent area (p=0.03), and holocallosal type (p0.005) significantly diminished the chances of cure of the AVM. CONCLUSIONS: AVMs of the corpus callosum seems to be difficult to treat with endovascular therapy alone. The goal of embolization should be prevention of (re) bleeding and a decrease in nidus size. Our experience regarding this sub-pathology suggests that a combination of endovascular therapy and radiotherapy may be the best option.

Predictive value of flat-panel CT for haemorrhagic transformations in patients with acute stroke treated with thrombectomy.

INTRODUCTION: Haemorrhagic transformations are pejorative for patients with acute ischaemic stroke (AIS). We estimated flat-panel CT performances to detect brain parenchymal hyperdense lesions immediately after mechanical thrombectomy directly on the angiography table in patients with AIS, and its ability to predict haemorrhagic transformation. We also evaluated an easy-reading protocol for post-procedure flat-panel CT evaluation by clinicians to enable them to determine the potential risk of haemorrhage. METHODS: Two neuroradiologists retrospectively reviewed post-procedural flat-panel CT and 24 h follow-up imaging. We evaluated hyperdense lesions on flat-panel CT to predict the occurrence of haemorrhagic transformation within 24 h detected with conventional imaging. RESULTS: Of 63 patients, 60.3% presented post-procedural parenchymal hyperdensity and 54.0% had haemorrhagic transformation. Significantly more patients with hyperdense lesions on post-thrombectomy flat-panel CT presented haemorrhagic transformation (84.2% vs 8.0%; p<0.0001). No significant haemorrhagic transformations were detected for patients without parenchymal hyperdensity. Sensitivity and specificity of hyperdense lesions on flat-panel CT for the prediction of haemorrhagic transformation were 94.1% (80.3-99.3%) and 79.3% (60.3-92.0%), respectively. The positive and negative predictive values for the occurrence of haemorrhage were 84.2% (68.8-94.0%) and 92.0% (74.0-99.0%), respectively. For significant parenchymal haemorrhage type 2, sensitivity and negative predictive values were 100%. We observed good homogeneity between the different readers. Hyperdensity on post-procedural flat-panel CT was associated with a tendency for higher risk of death and lower risk of good clinical outcome. CONCLUSIONS: Flat-panel CT appears to be a good tool to detect brain parenchymal hyperdensities after mechanical thrombectomy in patients with AIS and to predict haemorrhagic transformation.