Jean-Christophe Gentric

Does Aneurysmal Wall Enhancement on Vessel Wall MRI Help to Distinguish Stable From Unstable Intracranial Aneurysms

Background and Purpose— Arterial wall enhancement on vessel wall MRI was described in intracranial inflammatory arterial disease. We hypothesized that circumferential aneurysmal wall enhancement (CAWE) could be an indirect marker of aneurysmal wall inflammation and, therefore, would be more frequent in unstable (ruptured, symptomatic, or undergoing morphological modification) than in stable (incidental and nonevolving) intracranial aneurysms. Methods— We prospectively performed vessel wall MRI in patients with stable or unstable intracranial aneurysms. Two readers independently had to determine whether a CAWE was present. Results— We included 87 patients harboring 108 aneurysms. Interreader and intrareader agreement for CAWE was excellent (&kgr;=0.85; 95% confidence interval, 0.75–0.95 and &kgr;=0.90; 95% confidence interval, 0.83–0.98, respectively). A CAWE was significantly more frequently seen in unstable than in stable aneurysms (27/31, 87% versus 22/77, 28.5%, respectively; P<0.0001). Multivariate logistic regression, including CAWE, size, location, multiplicity of aneurysms, and daily aspirin intake, revealed that CAWE was the only independent factor associated with unstable status (odds ratio, 9.20; 95% confidence interval, 2.92–29.0; P=0.0002). Conclusions— CAWE was more frequently observed in unstable intracranial aneurysms and may be used as a surrogate of inflammatory activity in the aneurysmal wall.

Prognostic factors for outcomes after mechanical thrombectomy with solitaire stent

BACKGROUND AND PURPOSE Endovascular mechanical thrombectomy is emerging as a promising therapeutic approach for acute ischemic stroke. This study was aimed at identifying factors influencing outcomes after thrombectomy with a Solitaire stent device. MATERIALS AND METHODS Forty-five consecutive patients treated with thrombectomy using Solitaire FR were retrospectively included. Clinical, imaging and logistic variables were analyzed. A multivariate logistic regression analysis was used to identify variables influencing clinical outcome, based on discharge NIHSS score change and mRS at 3 months. RESULTS Patient mean age and initial NIHSS score was 58 years (range 24-88) and 17 (range 6-32), respectively. An MRI was performed for 80% of patients, showing severe DWI lesion for 28% of patients and associated FLAIR hyperintensity for 58% of patients. Mean time from symptom onset to recanalization was 299min for the 32 ACO and 473min for the 13 PCO. Angiographic efficacy (TICI 2b-3) was achieved for 93% of patients and good clinical outcomes at discharge and at 3 months (mRS≤2) were achieved for 49% and 58% of patients, respectively. Independent prognostic factors for predicting good clinical outcomes at discharge were a short time to recanalization and FLAIR negativity. At 3 months, they were a short time to recanalization and patient age. DWI lesion severity was an associated prognostic factor. CONCLUSION Two main prognostic factors for predicting a good clinical outcome after thrombectomy at 3 months were short time from symptom onset to recanalization and patient age.

Early CT changes in patients admitted for thrombectomy Intrarater and interrater agreement

Objective: To systematically review the literature and assess agreement on the Alberta Stroke Program Early CT Score (ASPECTS) among clinicians involved in the management of thrombectomy candidates. Methods: Studies assessing agreement using ASPECTS published from 2000 to 2015 were reviewed. Fifteen raters reviewed and scored the anonymized CT scans of 30 patients recruited in a local thrombectomy trial during 2 independent sessions, in order to study intrarater and interrater agreement. Agreement was measured using intraclass correlation coefficients (ICCs) and Fleiss kappa statistics for ASPECTS and dichotomized ASPECTS at various cutoff values. Results: The review yielded 30 articles reporting 40 measures of agreement. Populations, methods, analyses, and results were heterogeneous (slight to excellent agreement), precluding a meta-analysis. When analyzed as a categorical variable, intrarater agreement was slight to moderate (κ = 0.042–0.469); it reached a substantial level (κ > 0.6) in 11/15 raters when the score was dichotomized (0–5 vs 6–10). The interrater ICCs varied between 0.672 and 0.811, but agreement was slight to moderate (κ = 0.129–0.315). Even in the best of cases, when ASPECTS was dichotomized as 0–5 vs 6–10, interrater agreement did not reach a substantial level (κ = 0.561), which translates into at least 5 of 15 raters not giving the same dichotomized verdict in 15% of patients. Conclusions: In patients considered for thrombectomy, there may be insufficient agreement between clinicians for ASPECTS to be reliably used as a criterion for treatment decisions.

Flow diversion in the treatment of aneurysms: a randomized care trial and registry

OBJECTIVE The Flow Diversion in the Treatment of Intracranial Aneurysm Trial (FIAT) was designed to guide the clinical use of flow diversion, an innovative method to treat intracranial aneurysms, within a care trial and to study safety and efficacy. METHODS FIAT, conducted in 3 Canadian hospitals, proposed randomized allocation to flow diversion or standard management options (observation, coil embolization, parent vessel occlusion, or clip placement), and a registry of non-randomized patients treated with flow diversion. The primary safety outcome was death or dependency (modified Rankin Scale score > 2) at 3 months, to be determined for all patients who received flow diversion at any time. The primary efficacy outcome was angiographic occlusion at 3-12 months combined with an independent clinical outcome. RESULTS Of 112 participating patients recruited between May 2, 2011, and February 25, 2015, 78 were randomized (39 in each arm), and 34 received flow diversion within the registry. The study was halted due to safety concerns. Twelve (16%) of 75 patients (95% CI 8.9%-26.7%) who were allocated to or received flow diversion at any time were dead (n = 8) or dependent (n = 4) at 3 months or more, crossing a predefined safety boundary. Death or dependency occurred in 5 (13.2%) of 38 patients randomly allocated and treated by flow diversion (95% CI 5.0%-28.9%) and in 5 (12.8%) of 39 patients allocated to standard treatment (95% CI 4.8%-28.2%). Efficacy was below expectations of the trial hypothesis: 16 (42.1%) of 38 patients (95% CI 26.7%-59.1%) randomly allocated to flow diversion failed to reach the primary outcome, as compared with 14 (35.9%) of 39 patients allocated to standard treatment (95% CI 21.7%-52.9%). CONCLUSIONS Flow diversion was not as safe and effective as hypothesized. More randomized trials are needed to determine the role of flow diversion in the management of aneurysms. Clinical trial registration no.: NCT01349582 (clinicaltrials.gov).

One-Year MR Angiographic and Clinical Follow-Up after Intracranial Mechanical Thrombectomy Using a Stent Retriever Device

BACKGROUND AND PURPOSE: Little is known about the consequences of arterial wall damage that may be due to mechanical endovascular thrombectomy. Our aim was to perform 1-year MR angiographic and clinical follow-up of patients treated with mechanical endovascular thrombectomy using the Solitaire device. MATERIALS AND METHODS: Patients with stroke treated between August 2010 and July 2012 were prospectively evaluated with a minimum follow-up of 1 year after mechanical endovascular thrombectomy. Angiographic follow-up was performed on a 3T MR imaging scanner and included intracranial artery TOF MRA and supra-aortic artery gadolinium-enhanced MRA. Images were assessed to detect arterial abnormalities (stenosis, occlusion, dilation) and were compared with the final post-mechanical endovascular thrombectomy run to differentiate delayed and pre-existing abnormalities. Clinical evaluation was performed with the mRS and the 36-Item Short-Form Health Survey questionnaire quality-of-life scale. RESULTS: Thirty-nine patients were angiographically assessed at the mean term of 19 ± 4 months. MRA showed intracranial artery abnormalities in 10 patients, including 5 delayed intracranial artery abnormalities in 4 patients (4 stenoses and 1 dilation), 4 cases of pre-existing intracranial artery stenosis, and 2 occlusions. Pre-existing etiologic cervical artery stenosis or occlusion was observed in 2 patients. All these patients remained asymptomatic during the follow-up period. A significant clinical improvement was observed at 1-year follow-up in comparison with 3-month follow-up (P < .0001), with a good outcome achieved in 62.5% of patients and an acceptable quality of life restored. CONCLUSIONS: One-year follow-up identifies delayed asymptomatic arterial abnormalities in patients treated with the Solitaire device.

Association between posterior fossa arteriovenous malformations and prenidal aneurysm rupture: potential impact on management

OBJECT In patients with posterior fossa arteriovenous malformations (AVMs) who present with hemorrhage, feeding artery aneurysms are often the source of bleeding. The aim of this study was to evaluate the relative proportions of cases of infra- and supratentorial AVMs in which patients presented with prenidal aneurysm rupture. The management and outcome of 9 cases of posterior fossa AVMs associated with prenidal aneurysm rupture are presented. METHODS The authors retrospectively reviewed 233 consecutive AVM cases involving patients treated at their institution between April 2001 and August 2012. Patients with a prenidal aneurysm as the cause of the hemorrhage were identified. The frequencies of prenidal aneurysm-related ruptures were compared in cases of supra- and infratentorial AVMs. Management and clinical outcome (modified Rankin Scale [mRS] score) of patients with posterior fossa AVMs treated for ruptured prenidal aneurysms were recorded. RESULTS Of 233 AVMs, 25 (11%) were in the posterior fossa, and in 22 (88%) of these cases, the patients presented with hemorrhage, including 9 patients (41%) who presented with hemorrhage due to prenidal aneurysm rupture. Of 208 patients with supratentorial AVMs, 107 (51%) presented with hemorrhage, including 5 patients (4.7%) in whom the hemorrhage was associated with a prenidal aneurysm (p < 0.01). All 9 patients with posterior fossa AVMs and prenidal aneurysm rupture were treated with early embolization of the offending aneurysm. There was no early rebleeding or clinical complication related to this approach. At the end of follow-up (mean 46.8 months), 2 patients had an mRS score of 0, 1 had a score of 1, 3 had a score of 2, 2 patients were dead (mRS score of 6), and 1 patient was lost to follow-up. CONCLUSIONS Posterior fossa AVM hemorrhages are frequently associated with prenidal arterial aneurysms. Urgent endovascular treatment of the aneurysm was effective in this case series.

Value of spontaneous hyperdensity of cerebral venous thrombosis on helical CT.

Background Excluding a cerebral venous thrombosis (CVT) through imaging is a frequent request in the emergency setting. This assessment often starts by an unenhanced brain computed tomography (CT). Purpose Re-evaluate the value of spontaneous hyperdensity of CVT on helical unenhanced brain CT. Methods Multicentric retrospective study on CVT probability based on visual assessment of spontaneous hyperdensity of cerebral venous system, performed by four blinded radiologists, individually then collectively, on a population including 14 helical unenhanced brain CTs with CVT and 102 unenhanced brain CTs without CVT (all confirmed by CT or magnetic resonance [MR] venography). Exclusion criteria: no DICOM image, symptoms >15 days, CVT indirect signs on unenhanced CT. A fifth radiologist set 768 regions of interest to measure and to compare the density within the normal venous sinuses and the CVTs. Results After consensus reading, sensitivity of this sign for CVT diagnosis was 100%, specificity 95.1%, and negative predictive value (NPV) 100%, with high individual NPV (99–100%). Area under the receiver-operating characteristic curve was 0.992 after consensus (0.976–0.986 individually). The spontaneous density was significantly different (P <0.05) between normal sinuses and CVTs, with a density >70 HU reported only within the CVTs, except for the horizontal part of the superior sagittal sinus (hSSS). Conclusion The dense triangle sign on helical unenhanced brain CT has an excellent NPV to exclude a sinus thrombosis during the first 2 weeks. However, we believe that visual assessment of spontaneous hyperdensity is not sufficient for the diagnosis of CVT, with possible false-positive of the hSSS on unenhanced CT.

Contribution of embryology in the understanding of cervical venous system anatomy within and around the transverse foramen: a review of the classical literature.

Abstract Anatomic arrangement of venous system within the transverse foramen is a controversial topic among authors. Precise knowledge of this arrangement is necessary in imaging where vertebral artery dissection is suspected, as well as in surgical approaches of cervical spine. This knowledge objective cannot be achieved without a prerequisite knowledge of primitive venous system. We present here an update on the development of the transverse foramen venous system through a literature review. Our review of the classical literature aimed at synthesis of available related embryological knowledge and relating this synthesis to cervical vertebrae anatomy. Our findings with regard to different primitive descriptions were consistent and often complementary across the studies. The description has varied from a single vertebral vein to a single vein divided at certain areas, or even to a confluence of venous plexus. In this manner, the embryonic knowledge for instance on venous system can help us to better understand the segmental development of vertebral veins and their plexus arrangement. Furthermore, the cranial–caudal embryology, in particular of the nervous system, conveys the initial plexiform arrangement of vertebral veins, which ends into a single venous trunk joining the subclavian vein.

Testing Stenting and Flow Diversion Using a Surgical Elastase-Induced Complex Fusiform Aneurysm Model

BACKGROUND AND PURPOSE: Rabbit elastase-induced saccular aneurysms have been commonly used for preclinical testing of endovascular devices, including flow diverters. However, all tested devices have been shown to be capable of aneurysm occlusion with this model. We aimed to create a more challenging model to test and discriminate among neurovascular devices of varying efficacies. MATERIALS AND METHODS: With a surgical approach that included elastase infusion and balloon dilation, we attempted the creation of complex fusiform aneurysms in 16 rabbits, with standard saccular carotid aneurysms created in 15 other animals. Aneurysms were randomly allocated to one of the following treatments: flow diversion (n = 8), high-porosity stent (n = 6), double high-porosity stent (n = 5), and control (n = 6). Angiographic assessment and pathologic analyses were performed at 3 months. RESULTS: Creation of complex fusiform and standard saccular aneurysms was successful in 12/16 and 13/15 attempts, respectively. All saccular (n = 4) or complex fusiform (n = 4) aneurysms treated with flow diverters were successfully occluded. Three of 3 saccular compared with 0/2 complex fusiform aneurysms were occluded by double high-porosity stents. One of 3 saccular and 0/3 complex fusiform aneurysms were occluded by a single high-porosity stent. Both aneurysm types shared the same pathologic findings when untreated: The aneurysm wall lacked an elastic layer and smooth muscle cells, while the lumen was lined with neointima of varying thickness. Neointimal coverage of the devices was complete when aneurysms were occluded, while leaks were always associated with aneurysm remnants. CONCLUSIONS: Challenging fusiform aneurysms can be created in rabbits by using a surgical modification of the elastase method.

Venous organization in the transverse foramen: dissection, histology, and magnetic resonance imaging

OBJECT The anatomical arrangement of the venous system within the transverse foramen is controversial; there is disagreement whether the anatomy consists of a single vertebral vein or a confluence of venous plexus. Precise knowledge of this arrangement is necessary in imaging when vertebral artery dissection is suspected, as well as in surgical approaches for the cervical spine. This study aimed to better explain anatomical organization of the venous system within the transverse foramen according to the Trolard hypothesis of a transverse vertebral sinus. METHODS This was an anatomical and radiological study. For the anatomical study, 10 specimens were analyzed after vascular injection. After dissection, histological cuts were prepared. For the radiological study, a high-resolution MRI study with 2D time-of-flight segment MR venography sequences was performed on 10 healthy volunteers. RESULTS Vertebral veins are arranged in a plexiform manner within the transverse canal. This arrangement begins at the upper part of the transverse canal before the vertebral vein turns into a single vein along with the vertebral artery running from the transverse foramen of the C-6. This venous system runs somewhat ventrolaterally to the vertebral artery. In most cases, this arrangement is symmetrical and facilitates radiological readings. The anastomoses between vertebral veins and ventral longitudinal veins are uniform and arranged segmentally at each vertebra. CONCLUSIONS These findings confirm recent or previous anatomical descriptions and invalidate others. It is hard to come up with a common description of the arrangement of vertebral veins. The authors suggest providing clinicians as well as anatomists with a well-detailed description of components essential to the understanding of this organization.