Prognosis and risk factors associated with asymptomatic intracranial hemorrhage after endovascular treatment of large vessel occlusion stroke: a prospective multicenter cohort study

BACKGROUND AND PURPOSE

Asymptomatic intracranial hemorrhage (aICH) is a common occurrence after endovascular treatment (EVT) for acute ischemic stroke (AIS). The aims of this study were to address its impact on 3-month functional outcome and to identify risk factors for aICH after EVT.

METHODS

Patients with AIS attributable to anterior circulation large vessel occlusion who underwent EVT were enrolled in a multicenter prospective registry. Based on imaging performed 22-36 h post-EVT, we included patients with no intracranial hemorrhage (ICH) or aICH. Poor outcome defined as a 3-month modified Rankin Scale (mRS) score 4-6 and overall 3-month mRS score distribution were compared according to presence/absence of aICH, and aICH subtype using logistic regression. We assessed the risk factors of aICH using a multivariate logistic regression model.

RESULTS

Of the 1526 patients included in the study, 653 (42.7%) had aICH. Patients with aICH had a higher rate of poor outcome: odds ratio (OR) 1.88 (95% confidence interval [CI] 1.44-2.44). Shift analysis of mRS score found a fully adjusted OR of 1.79 (95% CI 1.47-2.18). Hemorrhagic infarction (OR 1.63 [95% CI 1.22-2.18]) and parenchymal hematoma (OR 2.99 [95% CI 1.77-5.02]) were associated with higher risk of poor outcome. Male sex, diabetes, coronary artery disease, baseline National Institutes of Health Stroke Scale score and Alberta Stroke Program Early Computed Tomography Score, number of passes and onset to groin puncture time were independently associated with aICH.

CONCLUSIONS

Patients with aICH, irrespective of the radiological pattern, have a worse functional outcome at 3 months compared with those without ICH after EVT for AIS. The number of EVT passes and the time from onset to groin puncture are factors that could be modified to reduce deleterious ICH.

Characterization of 3D bifurcations in micro-scan and MRA-TOF images of cerebral vasculature for prediction of intra-cranial aneurysms

An aneurysm is a vascular disorder where ballooning may form in a weakened section of the wall in the blood vessel. The swelling of the aneurysm may lead to its rupture. Intra-cranial aneurysms are the ones presenting the higher risks. If ruptured, the aneurysm may induce a subarachnoid haemorrhage which could lead to premature death or permanent disability. In this study, we are interested in locating and characterizing the bifurcations of the cerebral vascular tree. We use a 3D skeletonization combined with a graph-based approach to detect the bifurcations. In this work, we thus propose a full geometric characterisation of the bifurcations and related arteries. Aside from any genetic predisposition and environmental risk factors, the geometry of the brain vasculature may influence the chance of aneurysm formation. Among the main achievements, in this paper, we propose accurate, predictive 3D measurements of the bifurcations and we furthermore estimate the risk of occurrence of an aneurysm on a given bifurcation.

Two-layered susceptibility vessel sign is associated with biochemically quantified thrombus red blood cell content

BACKGROUND AND PURPOSE

Better characterization of the thrombus could be useful to determine acute ischaemic stroke (AIS) aetiology and predict response to thrombolysis and endovascular therapy (EVT). To test the hypothesis that susceptibility vessel sign (SVS) on baseline magnetic resonance imaging (MRI) is related to red blood cell (RBC) content of AIS thrombi, the total haemoglobin contents (HbCs) of AIS thrombi retrieved by EVT from patients with or without SVS or two-layered SVS (TLSVS) were compared.

METHODS

Baseline MRI of 84 anterior AIS patients was reviewed by neuro-radiologists blinded to clinical and biochemical data. Thrombi from these patients were retrieved by EVT and analysed for HbC by quantitative enzyme-linked immunosorbent assay and measurement of haem concentration.

RESULTS

Susceptibility vessel sign and TLSVS were respectively observed in 85.7% and 50.0% of cases. The median HbC content was 253 µg/mg thrombus (interquartile range 177-333) and the median haem content was 219 µg/mg thrombus (131-264). Thrombus HbC and haem content were highly correlated with thrombus RBC content determined by flow cytometry (r = 0.94). Thrombi from patients with TLSVS weighed more [31.1 (16.5-68.3) mg vs. 17.7 (11.7-33.3) mg; P = 0.005] and had a higher HbC content [278 (221-331) µg/mg vs. 196 (139-301) µg/mg; P = 0.010] compared to thrombi from patients without TLSVS. There was no difference in thrombus weight or HbC content according to SVS status.

CONCLUSIONS

Our study shows that TLSVS is significantly associated with a higher thrombus weight and RBC content, as determined by quantitative assays.

MRI Quantitative T2* Mapping to Predict Dominant Composition of In Vitro Thrombus

BACKGROUND AND PURPOSE

MR imaging quantitative T2* mapping, which provides information about thrombus composition and specifically the red blood cell content, may be obtained in the setting of acute ischemic stroke before treatment. This could be useful to adapt the endovascular strategy. We aimed to analyze the red blood cell content of in vitro thrombi in relation to the thrombus-T2* relaxation time.

MATERIALS AND METHODS

Thirty-five thrombus analogs of different compositions were scanned with an MR imaging quantitative T2* mapping sequence. Two radiologists, blinded to thrombus composition, measured the thrombus-T2* relaxation time twice at an interval of 2 weeks. Quantitative histologic evaluations of red blood cell content were performed. Inter- and intraobserver reproducibility of the thrombus-T2* relaxation time was assessed by calculating intraclass correlation coefficients. Finally, a Spearman product moment correlation between the thrombus-T2* relaxation time and red blood cell content was performed.

RESULTS

The median thrombus-T2* relaxation time was 78.5 ms (range, 16-268 ms; interquartile range, 60.5 ms). The median red blood cell content was 55% (range, 0%-100%; interquartile range, 75%). Inter- and intraobserver reproducibility of the thrombus-T2* relaxation time was excellent (>0.9). The Spearman rank correlation test found a significant inverse correlation between thrombus-T2* relaxation time and red blood cell content (ρ = -0.834, P < .001).

CONCLUSIONS

MR imaging quantitative T2* mapping can reliably identify the thrombus red blood cell content in vitro. This fast, easy-to-use sequence could be implemented in routine practice to predict stroke etiology and adapt devices or techniques for endovascular treatment of acute ischemic stroke.

MRI quantitative T2* mapping on thrombus to predict recanalization after endovascular treatment for acute anterior ischemic stroke

BACKGROUND

In anterior acute ischemic stroke (AAIS) treated with endovascular treatment (EVT), the susceptibility vessel sign (SVS+ or SVS-) is related to recanalization results (TICI 2b/3) and clinical outcome. However, a binary qualitative assessment of thrombus using SVS does not reflect its complex composition. Our aim was to assess whether a quantitative MRI marker, Thrombus-T2* relaxation time, may be assessable in clinical routine and may to predict early successful recanalization after EVT, defined as a TICI 2b/3 recanalization obtained in 2 attempts or less.

MATERIAL AND METHODS

Thrombus-T2* relaxation time was prospectively obtained from consecutive AAIS patients treated by EVT (concomitant aspiration and stent retriever). Quantitative values were compared between early recanalization and late or unsuccessful recanalization.

RESULTS

Thirty patients with AAIS were included and Thrombus-T2* relaxation time was obtained in all patients. Earlier TICI 2b/3 recanalization were obtained in 22 patients (73%) and was significantly associated with SVS+ (1/8 vs. 16/22, P=0.01) and a shorter Thombus-T2* relaxation time (mean SD, range: 257, 18-50ms vs. 45 9, 35-60ms, P<0.001).

CONCLUSION

A new quantitative MRI biomarker, the Thrombus-T2* relaxation time is assessable in clinical routine. In a preliminary study of 30 patients, a shorter Thombus-T2* relaxation time is related to earlier recanalization after EVT using combination of stent retriever and aspiration.

Hydrogel versus Bare Platinum Coils in Patients with Large or Recurrent Aneurysms Prone to Recurrence after Endovascular Treatment: A Randomized Controlled Trial

BACKGROUND AND PURPOSE

Some patients are at high risk of aneurysm recurrence after endovascular treatment: patients with large aneurysms (Patients Prone to Recurrence After Endovascular Treatment PRET-1) or with aneurysms that have previously recurred after coiling (PRET-2). We aimed to establish whether the use of hydrogel coils improved efficacy outcomes compared with bare platinum coils.

MATERIALS AND METHODS

PRET was an investigator-led, pragmatic, multicenter, parallel, randomized (1:1) trial. Randomized allocation was performed separately for patients in PRET-1 and PRET-2, by using a Web-based platform ensuring concealed allocation. The primary outcome was a composite of a residual/recurrent aneurysm, adjudicated by a blinded core laboratory, or retreatment, intracranial bleeding, or mass effect during the 18-month follow-up. Secondary outcomes included adverse events, mortality, and morbidity (mRS > 2). The hypothesis was that hydrogel would decrease the primary outcome from 50% to 30% at 18 months, necessitating 125 patients per group (500 for PRET-1 and PRET-2).

RESULTS

The trial was stopped once 250 patients in PRET-1 and 197 in PRET-2 had been recruited because of slow accrual. A poor primary outcome occurred in 44.4% (95% CI, 35.5%-53.2%) of those in PRET-1 allocated to platinum compared with 52.5% (95% CI, 43.4%-61.6%) of patients allocated to hydrogel (OR, 1.387; 95% CI, 0.838-2.295; P = .20) and in 49.0% (95% CI, 38.8%-59.1%) in PRET-2 allocated to platinum compared with 42.1% (95% CI, 32.0%-52.2%) allocated to hydrogel (OR, 0.959; 95% CI, 0.428-1.342; P = .34). Adverse events and morbidity were similar. There were 3.6% deaths (1.4% platinum, 5.9% hydrogel; P = .011).

CONCLUSIONS

Coiling of large and recurrent aneurysms is safe but often poorly effective according to angiographic results. Hydrogel coiling was not shown to be better than platinum.

WEB Treatment of Intracranial Aneurysms: Clinical and Anatomic Results in the French Observatory

BACKGROUND AND PURPOSE

Flow disruption with the WEB device is a new technique for the endovascular treatment of wide-neck bifurcation aneurysms. To obtain precise data regarding the safety and efficacy of this treatment with high-quality methodology, the prospective French Observatory study was conducted. Analysis of these data is presented, including 1-year follow-up.

MATERIALS AND METHODS

Patients with bifurcation aneurysms for which WEB treatment was indicated were included in this prospective, multicenter Good Clinical Practice study. Clinical data, including adverse events and clinical status at 1 month and 1 year, were collected and independently analyzed by a medical monitor. An independent core laboratory evaluated the anatomic results at 1 year following the procedure.

RESULTS

Ten French neurointerventional centers included 62 patients (39 women), 33-74 years of age (mean, 56.6 ± 9.80 years) with 63 aneurysms. Aneurysm locations were the middle cerebral artery in 32 aneurysms (50.8%), anterior communicating artery in 16 (25.4%), basilar artery in 9 (14.3%), and internal carotid artery terminus in 6 (9.5%). Morbidity and mortality at 1 month were, respectively, 3.2% (2/62 patients) and 0.0% (0/62). Morbidity and mortality (unrelated to the treatment) at 1 year were, respectively, 0.0% (0/59) and 3.4% (2/59 patients). At 1 year, complete occlusion was observed in 30/58 aneurysms (51.7%); neck remnant, in 16/58 aneurysms (27.6%); and aneurysm remnant, in 12/58 aneurysms (20.7%).

CONCLUSIONS

This prospective French Observatory study showed very good safety of aneurysm treatment with the WEB, with a high rate of adequate aneurysm occlusion at 1 year (79.3%).

WEB Treatment of Intracranial Aneurysms: Clinical and Anatomic Results in the French Observatory

BACKGROUND AND PURPOSE

Flow disruption with the WEB device is a new technique for the endovascular treatment of wide-neck bifurcation aneurysms. To obtain precise data regarding the safety and efficacy of this treatment with high-quality methodology, the prospective French Observatory study was conducted. Analysis of these data is presented, including 1-year follow-up.

MATERIALS AND METHODS

Patients with bifurcation aneurysms for which WEB treatment was indicated were included in this prospective, multicenter Good Clinical Practice study. Clinical data, including adverse events and clinical status at 1 month and 1 year, were collected and independently analyzed by a medical monitor. An independent core laboratory evaluated the anatomic results at 1 year following the procedure.

RESULTS

Ten French neurointerventional centers included 62 patients (39 women), 33-74 years of age (mean, 56.6 ± 9.80 years) with 63 aneurysms. Aneurysm locations were the middle cerebral artery in 32 aneurysms (50.8%), anterior communicating artery in 16 (25.4%), basilar artery in 9 (14.3%), and internal carotid artery terminus in 6 (9.5%). Morbidity and mortality at 1 month were, respectively, 3.2% (2/62 patients) and 0.0% (0/62). Morbidity and mortality (unrelated to the treatment) at 1 year were, respectively, 0.0% (0/59) and 3.4% (2/59 patients). At 1 year, complete occlusion was observed in 30/58 aneurysms (51.7%); neck remnant, in 16/58 aneurysms (27.6%); and aneurysm remnant, in 12/58 aneurysms (20.7%).

CONCLUSIONS

This prospective French Observatory study showed very good safety of aneurysm treatment with the WEB, with a high rate of adequate aneurysm occlusion at 1 year (79.3%).

Susceptibility Vessel Sign on MRI Predicts Favorable Clinical Outcome in Patients with Anterior Circulation Acute Stroke Treated with Mechanical Thrombectomy

BACKGROUND AND PURPOSE

The susceptibility vessel sign on MR imaging has been reported to indicate acute occlusion from erythrocyte-rich thrombus. The purpose of this study was to evaluate the influence of the susceptibility vessel sign seen on MR imaging before treatment on the clinical outcome after mechanical thrombectomy for anterior circulation acute stroke.

MATERIALS AND METHODS

We retrospectively included 73 consecutive patients who were treated for anterior circulation acute stroke by mechanical thrombectomy from December 2009 to September 2013. Each patient underwent MR imaging before mechanical thrombectomy. The presence (susceptibility vessel sign+) or absence of the susceptibility vessel sign (susceptibility vessel sign-) was recorded. Mechanical thrombectomy was performed either alone or in association with IV tPA according to the site and time after occlusion. Good functional outcome was defined by an mRS ≤ 2 at 3 months in susceptibility vessel sign+ and susceptibility vessel sign- groups. Patient clinical characteristics, initial NIHSS score and ASPECTS, site of occlusion, time between onset to groin puncture, TICI after mechanical thrombectomy, NIHSS score at day 1, and spontaneous hyperattenuation on CT at day 1 were also analyzed.

RESULTS

Fifty-three patients with susceptibility vessel sign+ and 20 with susceptibility vessel sign- were included in our study. mRS ≤ 2 at 3 months occurred in 65% patients in the susceptibility vessel sign+ group and 26% in the susceptibility vessel sign- group (P = .004). On multivariate analysis, the susceptibility vessel sign was the only parameter before treatment that could predict mRS ≤ 2 at 3 months (OR, 8.7; 95% CI, 1.1-69.4; P = .04).

CONCLUSIONS

Our study strongly suggests that the susceptibility vessel sign on MR imaging before treatment is predictive of favorable clinical outcome for patients presenting with anterior circulation acute stroke and treated with mechanical thrombectomy.

Endovascular treatment of wide-neck anterior communicating artery aneurysms using WEB-DL and WEB-SL: short-term results in a multicenter study

BACKGROUND AND PURPOSE

Endovascular treatment of wide-neck anterior communicating artery aneurysms can often be challenging. The Woven EndoBridge (WEB) device is a recently developed intrasaccular flow disrupter dedicated to endovascular treatment of intracranial aneurysms. The aim of this study was to investigate the feasibility, safety, and efficacy of the WEB Dual-Layer and WEB Single-Layer devices for the treatment of wide-neck anterior communicating artery aneurysms.

MATERIALS AND METHODS

Patients with anterior communicating artery aneurysms treated with the WEB device between June 2013 and March 2014 in 5 French centers were analyzed. Procedural success, technical complications, clinical outcome at 1 month, and immediate and 3- to 6-month angiographic follow-up results were analyzed.

RESULTS

Ten patients with unruptured anterior communicating artery aneurysms with a mean neck diameter of 5.4 mm were treated with the WEB. Treatment failed in 3 of the 10 aneurysms without further clinical complications. One patient developed a procedural thromboembolic event, and the other 6 had normal neurologic examination findings at 1-month follow-up. Immediate anatomic outcome evaluation showed adequate occlusion (total occlusion or neck remnant) in 6 of 7 patients. Angiographic control was obtained in all patients, including 6 adequate aneurysm occlusions (3 complete occlusions and 3 neck remnants) at short-term follow-up.

CONCLUSIONS

In our small series, treatment of wide-neck anterior communicating artery aneurysms with the WEB device was feasible and safe. However, patient selection based on the aneurysm and initial angiographic findings in the parent artery is important due to the limitations of the WEB device navigation.

WEB Treatment of Intracranial Aneurysms: Feasibility, Complications, and 1-Month Safety Results with the WEB DL and WEB SL/SLS in the French Observatory

BACKGROUND AND PURPOSE

Safety analyses in the French Observatory have shown that treatment of intracranial aneurysms by using flow disruption with the Woven EndoBridge Device (WEB) is safe, with low morbidity and no mortality. The objective of this study was to analyze treatment feasibility, complications, and safety results in patients treated with the Woven EndoBridge Device Dual-Layer (WEB DL) and Woven EndoBridge Device Single-Layer/Single-Layer Sphere (WEB SL/SLS) in the French Observatory.

MATERIALS AND METHODS

Patients with bifurcation aneurysms were included in this prospective, multicenter good clinical practices study. A medical monitor independently analyzed procedural and clinical data. The study started with the WEB DL, and secondarily, the WEB SL/SLS was authorized in the study.

RESULTS

Between November 2012 and January 2014, 10 French centers included 62 patients with 63 aneurysms. Thirty patients with 31 aneurysms were treated with the WEB DL, and 32 patients with 32 aneurysms, with the WEB SL/SLS. The percentage of anterior communicating artery aneurysms treated with WEB SL/SLS was significantly higher (37.5%) compared with WEB DL (12.9%) (P = .04). The WEB SL/SLS was more frequently used in aneurysms of <10 mm than the WEB DL (respectively, 96.9% and 67.7%; P = .002). Morbidity was similar in both groups (WEB DL, 3.3%; WEB SL/SLS, 3.1%), and mortality was 0.0% in both groups.

CONCLUSIONS

This comparative study shows increased use of WEB treatment in ruptured, small, and anterior communicating artery aneurysms when using WEB SL/SLS. There was a trend toward fewer thromboembolic complications with the WEB SL/SLS. With both the WEB DL and WEB SL/SLS, the treatment was safe, with low morbidity and no mortality.

WEB intrasaccular flow disruptor-prospective, multicenter experience in 83 patients with 85 aneurysms

BACKGROUND AND PURPOSE

The safety and efficacy of WEB flow disruption have been analyzed in small, retrospective series. The object of this study was to evaluate the safety and efficacy of WEB flow disruption in a large, multicenter, prospectively collected population.

MATERIALS AND METHODS

Data from all patients treated with the WEB-DL device between June 2011 and October 2013 in 11 French neurointerventional centers were prospectively collected and retrospectively analyzed. Complications occurring during and after treatment were analyzed as well as morbidity and mortality at 1 month. Aneurysm occlusion status at the last follow-up was analyzed.

RESULTS

Eighty-three patients with 85 aneurysms were included in this series. Technical success was achieved in 77 patients with 79 aneurysms (92.9%). Periprocedural complications were observed in 9 patients (10.8%), leading to permanent neurologic deficits in 3 (3.9%). Morbidity and mortality at 1 month were 1.3% and 0.0%, respectively. Angiographic follow-up was performed for 65/79 aneurysms (82.3%) 3-24 months after treatment (mean, 5.3 months). Complete aneurysm occlusion was observed in 37/65 aneurysms (56.9%); neck remnant, in 23/65 (35.4%); and aneurysm remnant, in 5/65 (7.7%).

CONCLUSIONS

In this large prospective series of patients, WEB flow disruption was a safe and efficient technique.

Patients prone to recurrence after endovascular treatment: periprocedural results of the PRET randomized trial on large and recurrent aneurysms

BACKGROUND AND PURPOSE

Some patients with large or recurrent aneurysms may be at increased risk of recurrence postcoiling. The Patients Prone to Recurrence after Endovascular Treatment (PRET) trial was designed to assess whether hydrogel coils were superior to platinum coils in these high-risk patients. This article reports periprocedural safety and operator-assessed angiographic results from the PRET trial.

MATERIALS AND METHODS

PRET was a pragmatic, multicenter, randomized controlled trial. Patients had ≥10-mm aneurysms (PRET-1) or a major recurrence after coiling of an aneurysm of any size (PRET-2). Patients were randomly allocated to hydrogel or control arms (any platinum coil) by using concealed allocation with minimization. Assist devices could be used as clinically required. Aneurysms could be unruptured or recently ruptured. Analyses were on an intent-to-treat basis.

RESULTS

Four hundred forty-seven patients were recruited (250 PRET-1; 197 PRET-2). Aneurysms were recently ruptured in 29% of PRET-1 and 4% of PRET-2 patients. Aneurysms were ≥10 mm in all PRET-1 and in 50% of PRET-2 patients. They were wide-neck (≥4 mm) in 70% and in the posterior circulation in 24% of patients. Stents were used in 28% of patients (35% in PRET-2). Coiling was successful in 98%. Adverse events occurred in 28 patients with hydrogel and 23 with platinum coils. Mortality (n=2, unrelated to treatment) and morbidity (defined as mRS>2 at 1 month) occurred in 25 patients (5.6%; 12 hydrogel, 13 platinum), related to treatment in 10 (4 hydrogel; 6 platinum) (or 2.3% of 444 treated patients). No difference was seen between hydrogel and platinum for any of the indices used to assess safety up to at least 30 days after treatment. At 1 month, 95% of patients were home with a good outcome (mRS≤2 or unchanged). Operator-assessed angiographic outcomes were satisfactory (complete occlusion or residual neck) in 339 of 447 or 76.4% of patients, with no significant difference between groups.

CONCLUSIONS

Endovascular treatment of large and recurrent aneurysms can be performed safely with platinum or hydrogel coils.

Infectious and metabolic brain imaging

Central nervous system infectious and metabolic disease is a vast domain. We have chosen to focus particularly on five pathological conditions: brain abscess, herpes encephalitis, Creutzfeldt-Jacob disease, posterior reversible encephalopathy and central pontine myelinolysis. We will pay particular attention to MRI signs and the specific sequences to use in each condition, in addition to the conventional sequences, in order to avoid diagnostic traps. Once the MRI exploration is complete, the diagnosis still cannot be established without knowing the clinical and metabolic context.

Cerebral ischemia complicating intracranial aneurysm: a warning sign of imminent rupture?

BACKGROUND AND PURPOSE

Patients harboring nongiant cerebral aneurysms may rarely present with an ischemic infarct distal to the aneurysm. The aim of this case series was to report clinical and radiologic characteristics of these patients, their management, and outcome.

MATERIALS AND METHODS

We undertook a single-center retrospective analysis of consecutive patients admitted during an 8-year period with an acute ischemic stroke revealing an unruptured nongiant (<25 mm) sacciform intracranial aneurysm. Clinical, radiologic, therapeutic, and follow-up data were analyzed.

RESULTS

Nine patients were included. The mean size of aneurysms was 9.6 ± 6 mm, and 5 were partially or totally thrombosed. Two patients had a fatal SAH within 3 days after stroke-symptom onset, whereas asymptomatic meningeal bleeding was diagnosed or suspected in 2 others. Most of the patients with unthrombosed aneurysms were successfully treated by endovascular coiling in the acute phase. Thrombosed aneurysms were usually treated with antithrombotics, and most recanalized secondarily, requiring endovascular treatment or surgical obliteration. No recurrence of an ischemic event or SAH was observed during the 31 ± 12 months of follow-up (from 4 to 53 months).

CONCLUSIONS

In this single-center series, the frequency of early SAH in patients with ischemic stroke distal to an unruptured intracranial aneurysm was high. Acute management should be undertaken with care regarding antithrombotic use, and early endovascular coiling should be considered.

Intra-aneurysmal thrombosis as a possible cause of delayed aneurysm rupture after flow-diversion treatment

BACKGROUND AND PURPOSE

FD technology enables reconstructive repair of otherwise difficult-to-treat intracranial aneurysms. These stentlike devices may induce progressive aneurysm thrombosis without additional implants and may initiate complete reverse vessel remodeling. The associated vascular biologic processes are as yet only partially understood.

MATERIALS AND METHODS

From 12 different centers, 13 cases of delayed postprocedural aneurysm rupture were recorded and analyzed. Symptom, aneurysm location and morphology, and the time elapsed from treatment until rupture were analyzed.

RESULTS

There were 10 internal carotid and 3 basilar artery aneurysms. Mean aneurysm diameter was 22 ± 6 mm. Eleven patients were symptomatic before treatment. A single FD was used for all saccular aneurysms, while fusiform lesions were treated by using multiple devices. A supplementary loose coiling of the aneurysm was performed in 1 patient only. Ten patients developed early aneurysm rupture after FD treatment (mean, 16 days; range, 2-48 days); in 3 patients, rupture occurred 3-5 months after treatment. In all cases, most of the aneurysm cavity was thrombosed before rupture. The biologic mechanisms predisposing to rupture under these conditions are reviewed and discussed

CONCLUSIONS

FDs alone may modify hemodynamics in ways that induce extensive aneurysm thrombosis. Under specific conditions, however, instead of reverse remodeling and cicatrization, aggressive thrombus-associated autolysis of the aneurysm wall may result in delayed rupture.

Electronic reference for absolute quantification of brain metabolites by 1H-MRS on clinical whole-body imaging

BACKGROUND AND PURPOSE

The electronic reference to access in vivo concentrations (ERETIC) method is a promising technique for absolute concentration quantification by brain proton magnetic resonance spectroscopy ((1)H-MRS). However, in its usual form, the technique cannot be implemented in most clinical MR scanners. For this reason, we propose a new strategy for transmitting the ERETIC signal before localized spectroscopy acquisition, thereby allowing its use in clinical MR scanners.

METHODS

ERETIC signal acquisition, using a dedicated sequence, was carried out immediately before the MR sequence. This approach was evaluated on phantoms of known metabolite concentrations and in 10 healthy volunteers. The results were then compared with those obtained using the water signal as reference.

RESULTS

Measurements in vitro showed that the standard deviations measured by the ERETIC method were similar to those using the water-signal reference method. Also, values for metabolite concentrations in vivo were in good agreement with those found in the literature for normal white matter in human brains. Concentrations obtained by ERETIC showed good linear correlation compared with the values obtained by the water-signal reference method.

CONCLUSION

Our preliminary study shows that the ERETIC method appears to be a reliable technique that can overcome most of the drawbacks observed with other absolute quantification methods. However, further studies involving larger patient groups are needed to confirm these findings.

[Acute anterograde amnesia by infarction of the mamillothalamic tracts]

We report a case of persistent anterograde amnesia secondary to an anterior thalamic infarct. A 49-year-old right-handed man is referred for acute anterograde amnesia. Diffusion-weighted imaging performed at 24 hours shows an acute punctiform infarct of the left anterior thalamus, while T2-weighted imaging reveals a contralateral and symmetrical ischemic sequelae in the right anterior thalamus. The two lesions are isolated and remarkably centered with the mamillothalamic tract. We suggest the symptoms are caused by the addition of the two lesions interrupting the mamillothalamic tracts. This is the second clinico-pathological observation of a persistent amnestic syndrome secondary to a bilateral lesion of the mamillothalamic tract.

[Presentation of cerebral toxocariasis with mental confusion in an adult: case report and review of the literature]

Toxocariasis is usually responsible for visceral larva migrans syndroms. Nervous system involvement is a rare complication. In this report, we describe one case of meningoencephalitis due to Toxocara canis in a 73-year-old man presenting with mental confusion. The diagnosis of cerebral toxocariasis was confirmed by immunodiagnosis in both serum and cerebro-spinal fluid. Cerebral toxocariasis may be suspected in patients presenting with some neurological patterns including: confusion, meningitis, meningo-encephalitis, meningo-myelitis, when the etiological assessment remains negative and the environmental context is favourable. Finding evidence of specific antibodies in both cerebro spinal fluid and serum is mandatory for the diagnosis. The main clinical features concerning cerebral toxocariasis, diagnostic tools, and therapeutic measures are discussed.

Diagnostic et traitement des fistules vertébrovertébrales

Vertebrovertebral Arteriovenous Fistula (V.V.A.V.F.) is a relatively rare entity. It may be an incidental finding or be detected in patients presenting with pulsatile tinnitus, cervical bruit, or vertebro-basilar insufficiency. It can be spontaneous but it most frequently is post-traumatic in etiology. The authors report 8 patients, 4 women and 4 men aged between 20 to 77 years, with 4 post-traumatic V.V.A.V.F. and 4 spontaneous V.V.A.V.F. that were seen over a 15 year period. Imaging work-up included Doppler US (n=4), MRI 9n=3) and angiography (n=8). Seven of 8 patients were treated successfully using an endovascular technique (5 with balloon occlusion, 1 with coil embolization and 1 using a mechanical maneuver), without complication or recurrence, except in one case. We compare our results with published reports from the literature and review the underlying pathology and management strategies of V.V.A.V.F.

[Transarterial embolisation of intracranial dural arteriovenous malformations with ethylene vinyl alcohol copolymer (Onyx18)]

OBJECTIVE

To report our recent experience in transarterial embolisation of dural arteriovenous malformations (DAVM) using a new liquid embolic agent, Onyx18.

PATIENTS AND METHODS

6 patients were enrolled in this series. Clinical presentation was separated into 2 groups: aggressive (n=2), non aggressive (n=4). The DAVM was located at the superior sagittal sinus (n=1), at the transverse sinus (n=2), at the condylian canal (n=1), in the lesser sphenoid wing region (n=1), and in the tentorium region (n=1). The DAVM drained directly into a condylian or a cortical vein for three patients and into a venous sinus with cortical venous reflux for the three others. In this latter situation, the sinus was anatomically excluded from the normal brain venous drainage.

RESULTS

A full brain angiogram including both internal carotid arteries, both external carotid arteries and ipsilateral vertebral artery, was performed before and after each treatment. The feeder chosen after a selective catheterisation for Onyx18 injection was always meningeal. Each treatment consisted of a single Onyx injection after one unique feeder catheterisation. Complete anatomical exclusion of the DAVM was achieved and demonstrated by the post treatment angiogram in all cases. There was no clinical complication after the treatment.

CONCLUSION

Onyx18 used is a safe treatment for DAVMs. When its injection is performed in optimal conditions, it fills the total DAVM and its drainage vein or sinus after a single arterial feeder catheterisation.

Anévrysmes intracrâniens révélés par une ischémie cérébrale

PURPOSE

To report four cases of patient with an acute ischemic event as a presenting symptom of a berry aneurysm.

PATIENTS AND METHODS

One male and three female (aged range 38 to 65 years) patients were admitted for acute stroke. The neuroradiologic finding disclosed aneurysm thrombosis, inferior to twenty five millimetres in three cases. Lumbar puncture was done in one case and showed subarachnoid haemorrage.

DISCUSSION

We will discuss the hypothesis leading to the mechanism of aneurysm thrombosis. Two theories will be presented: "hemodynamic" and "parietal" modifications. We will propose a management protocol for these patients with atypical presentation of intracranial aneurysms given the potential risk of rupture.

CONCLUSION

The natural history of intracranial aneurysms is still not fully understood. Nevertheless, aneurym thrombosis may occur and lead to ischemic stroke.

[The finding of incidental intracranial lesions with magnetic resonance imaging]

INTRODUCTION

Incidental findings on brain MRI are not rare since the development of MRI as a diagnostic and clinical research tool.

STATE OF THE ART

Prevalence of cerebral incidental finding, based on research volunteers participating in studies, is estimated from 1.7 to 4 percent. The most frequently detected lesions are intracranial tumors (meningioma, arachnoid cysts, neuro-epithelial tumor) and vascular malformations.

PERSPECTIVES

A better knowledge of the spontaneous outcome of incidental findings would allow adequate management of these patients.

CONCLUSION

Clinicians should be aware of the outcome of incidental findings, to reassure patients or trigger a work-up if necessary.

ARM des vaisseaux cervico-encéphaliques : technique, principales applications cliniques

Magnetic resonance angiography (MRA) is a very valuable tool in the routine evaluation of patients with stroke syndrome. It provides powerful noninvasive imaging of the cervical and intracranial vessels allowing the detection and the diagnosis of vascular anomalies. MRA usefully supplements, during the same examination, the analysis by MRI of the cerebral parenchyma. We will describe the indications of the various techniques (MRA with and without injection of contrast media) and show the value, artifacts and limitations of MRA in atherosclerotic stenosis or occlusive disease and in arterial dissections. This noninvasive vascular assessment will depend on the initial therapeutic orientation. Within the framework of the hemorrhagic stroke, we will discuss the role and the interest of dynamic MR angiography in the tracking and control of intracranial aneurysms and also the contribution of this newer sequences with gadolinium injection in the detection of cerebral vascular malformations.

Intérêt du blood-patch pour le traitement de l’hypotension intracrânienne spontanée

OBJECTIVE

Spontaneous intracranial hypotension (SIH) is a rare syndrome. It is due most often to a spinal meningeal leak. Symptoms due to SIH are often difficult to treat and epidural blood-patch (BP) has been proposed. The aim was to evaluate the effects and the problems associated with lumbar blood-patch to treat SIH.

STUDY DESIGN

Case series.

PATIENTS AND METHODS

The diagnosis of SIH was made in six consecutive patients on clinical signs and radiological findings (CT-scan and MRI). A lumbar BP (L1-L2 level) was performed as soon as possible after diagnosis. A maximum of three procedures was allowed in case of failure of the initial BP.

RESULTS

BP was effective and well tolerated for five patients (3 immediately after BP, 2 others patients needed 2 and 3 BP). In one patient, an incomplete response was observed and was related to a large CFS leak diagnosed by CT-myelogram.

CONCLUSION

When the diagnosis of spontaneous intracranial hypotension is confirmed, a repeated blood patch lumbar procedure can be efficient to treat these patients.

[Diffusion, perfusion and activation functional MRI studies of brain arteriovenous malformations]

The management of Brain Arteriovenous Malformations continues to be challenged by a lack of understanding and control of pathophysiological processes implied in the clinical symptoms. New data from functional MRI with diffusion-weighted, perfusion-weighted and neuronal activation highlight abnormal brain areas near or remote to the AVM nidus. Moreover, these techniques are able to show hemodynamic and neuronal adaptative phenomena involved in brain plasticity. They reflect the instantaneous hemodynamic brain conditions that may help to correlate the clinical symptoms with the anatomical and functional substratum and to influence any invasive therapy.