C. Rodriguez-Régent

Intracranial Aneurysms: Recurrences More than 10 Years after Endovascular Treatment—A Prospective Cohort Study, Systematic Review, and Meta-Analysis

PURPOSE To assess the efficacy of endovascular treatment (EVT) of intracranial aneurysms for recurrence, bleeding, and de novo aneurysm formation at long-term follow-up (> 10 years after treatment) with magnetic resonance (MR) angiography and to identify risk factors for recurrence through a prospective study and a systematic review of the literature. MATERIALS AND METHODS Clinical examinations and 3-T MR angiography were performed prospectively 10 years after EVT of intracranial aneurysms in a single institution. Ethics committee approval and informed consent were obtained. PubMed, EMBASE, and Cochrane databases were searched to identify studies in which authors reported bleeding and/or aneurysm recurrence rates in patients who received follow-up more than 10 years after EVT. Univariate and multivariate subgroup analyses were performed to identify risk factors (midterm MR angiographic results, aneurysm characteristics, retreatment within 5 years). RESULTS In the prospective study, sac recanalization occurred between midterm and long-term MR angiography in 16 of 129 (12.4%) aneurysms. Grade 2 classification on the Raymond scale at midterm MR angiography (relative risk [RR], 4.16; 99% confidence interval [CI]: 2.12, 8.14) and retreatment within 5 years (RR, 4.67; 99% CI: 1.55, 14.03) were risk factors for late recurrence. In the systematic review (15 cohorts, 2773 patients, 2902 aneurysms), bleeding, aneurysm recurrence, and de novo lesion formation rates were, respectively, 0.7% (99% CI: 0.2%, 2.7%; I(2), 0%; one of 694 patients), 11.4% (99% CI: 7.0%, 18.0%; I(2), 21.6%), and 4.1% (99% CI: 1.7, 9.4%; I(2), 54.1%). Raymond grade 2 initial result (RR, 7.08; 99% CI: 1.24, 40.37; I(2), 82.6%) and aneurysm size greater than 10 mm (RR, 4.37; 99% CI: 1.83, 10.44; I(2), 0%) were risk factors for late recurrence. CONCLUSION EVT of intracranial aneurysm is effective for prevention of long-term bleeding, but recurrences occur in a clinically relevant percentage of patients, a finding that may justify follow-up of selected patients for 10 years or more, such as patients with aneurysms larger than 10 mm or classified as Raymond grade 2 at midterm MR angiography.

Non-invasive diagnosis of intracranial aneurysms

Patients need to be examined for intracranial aneurysms if they have had a subarachnoid hemorrhage. The preferred technique in this situation is CT angiography. Screening can be done for familial forms or for elastic tissue disorders, for which the first line investigation is magnetic resonance angiography. These non-invasive methods have now taken over from conventional angiography that was reserved for the pretreatment phase. A good technical knowledge of these imaging methods, their artifacts and misleading images enables reliable detection of intracranial aneurysms and for an accurate report to be returned to clinicians.

MR Selective Flow-Tracking Cartography: A Postprocessing Procedure Applied to Four-dimensional Flow MR Imaging for Complete Characterization of Cranial Dural Arteriovenous Fistulas

PURPOSE To assess the feasibility of a selective flow-tracking cartographic procedure applied to four-dimensional (4D) flow imaging and to demonstrate its usefulness in the characterization of dural arteriovenous fistulas (DAVFs). MATERIALS AND METHODS Institutional review board approval was obtained, and all patients provided written informed consent. Eight patients (nine DAVFs) underwent 3.0-T magnetic resonance (MR) imaging and digital subtraction angiography (DSA). Imaging examinations were performed within 24 hours of each other. 4D flow MR imaging was performed by using a 4D radial phase-contrast vastly undersampled isotropic projection reconstruction pulse sequence with an isotropic spatial resolution of 0.86 mm (5 minutes 35 seconds). Two radiologists independently reviewed images from MR flow-tracking cartography and reported the location of arterial feeder vessels and the venous drainage type and classified DAVFs according to the risk of rupture (Cognard classification). These results were compared with those at DSA. Quadratic weighted κ statistics with their 95% confidence intervals (CIs) were used to test intermodality agreement in the identification of arterial feeder vessels, draining veins, and Cognard classification. RESULTS Interreader agreement for shunt location on MR images was perfect (κ = 1), with good-to-excellent interreader agreement for arterial feeder vessel identification (κ = 0.97; 95% CI = 0.92, 1.0), and matched in all cases with shunt location defined at DSA. There was good-to-excellent agreement between MR cartography and DSA in the definition of the main feeding arteries (κ = 0.92; 95% CI = 0.83, 1.0), presence of retrograde flow in dural sinuses (κ = 1), presence of retrograde cortical venous drainage (κ = 1), presence of venous ectasia (κ = 1), and final Cognard classification of DAVFs (κ = 1, standard error = 0.35). CONCLUSION MR selective flow-tracking cartography enabled the noninvasive characterization of cranial DAVFs.

Role of MRA in the detection of intracranial aneurysm in the acute phase of subarachnoid hemorrhage

BACKGROUND Magnetic resonance angiography (MRA) has been evaluated for the detection of unruptured intracranial aneurysms with favorable results at 3 Tesla (3T) and with similar diagnostic accuracy as both 3D time-of-flight (3D-TOF) and contrast-enhanced (CE-MRA) MRA. However, the diagnostic value and place of MRA in the detection of ruptured aneurysms has been little evaluated. Thus, the goal of this prospective single-center series was to assess the feasibility and diagnostic value of 3T 3D-TOF MRA and CE-MRA for aneurysm detection in acute non-traumatic subarachnoid hemorrhage (SAH). METHODS From March 2006 to December 2007, all consecutive patients admitted to our hospital with acute non-traumatic SAH (≤10 days) were prospectively included in this study evaluating MRA in the diagnostic workup of SAH. Feasibility of MRA and sensitivity/specificity of 3D-TOF and CE-MRA were assessed compared with gold standard DSA. RESULTS In all, 84 consecutive patients (45 women, 39 men; age 23-86 years) were included. The feasibility of MRA was low (43/84, 51.2%). The reasons given for patients not undergoing magnetic resonance imaging (MRI) examination were clinical status (27 patients), potential delay in aneurysm treatment (11 patients) and contraindications to MRI (three patients). In patients explored by MRA, the sensitivity of CE-MRA (95%) was higher compared with 3D-TOF (86%) with similar specificity (80%). Also, 3D-TOF missed five aneurysms while CE-MRA missed two. CONCLUSION The value of MRA in the diagnostic workup of ruptured aneurysms is limited due to its low feasibility during the acute phase of bleeding. Sensitivity for aneurysm detection was good for both MRA techniques, but tended to be better with CE-MRA.

Advanced technologies applied to physiopathological analysis of central nervous system aneurysms and vascular malformations

While depiction and definition of morphological and architectural characteristics of CNS vascular disorders remains the first step of an MR analysis, emerging imaging techniques offer new functional information that might help to characterize rupture risk of CNS vascular disorders. Two main orientations are suggested by recent studies: inflammation of the vessel wall and analysis of physical constraints of blood flow using 4D flow imaging (shear parietal). This paper will focus on radiological application of 4D flow imaging and inflammation imaging, in the characterization of potential prognostic markers of CNS vascular disorders. We will review the basic technical considerations of 4D flow MRA, inflammation imaging and discuss their applications in CNS vascular disorders: aneurysms, arteriovenous malformation, dural arteriovenous fistulas. We will illustrate their potential in the development of individual rupture risk criteria in brain vascular disorders.

Tips and traps in brain MRI: Applications to vascular disorders

The French Society of Radiologys guide to good use of medical imaging examinations recommends MRI as the first-line examination for exploring cerebrovascular events or disorders. This paper will discuss the main traps in the images when stroke is suspected and provide the technical tips or knowledge necessary for an optimal radiological report.

Circumferential Thick Enhancement at Vessel Wall MRI Has High Specificity for Intracranial Aneurysm Instability

Purpose To identify wall enhancement patterns on vessel wall MRI that discriminate between stable and unstable unruptured intracranial aneurysm (UIA). Materials and Methods Patients were included from November 2012 through January 2016. Vessel wall MR images were acquired at 3 T in patients with stable (incidental and nonchanging over 6 months) or unstable (symptomatic or changing over 6 months) UIA. Each aneurysm was evaluated by using a four-grade classification of enhancement: 0, none; 1, focal; 2, thin circumferential; and 3, thick (>1 mm) circumferential. Inter- and intrareader agreement for the presence and the grade of enhancement were assessed by using κ statistics and 95% confidence interval (CI). The sensitivity, specificity, and negative and positive predictive values of each enhancement grade for differentiating stable from unstable aneurysms was compared. Results The study included 263 patients with 333 aneurysms. Inter- and intrareader agreement was excellent for both the presence of enhancement (κ values, 0.82 [95% CI: 0.67, 0.99] and 0.87 [95% CI: 0.7, 1.0], respectively) and enhancement grade (κ = 0.92 [95% CI: 0.87, 0.95]). In unruptured aneurysms (n = 307), grade 3 enhancement exhibited the highest specificity (84.4%; 233 of 276; 95% CI: 80.1%, 88.7%; P = .02) and negative predictive value (94.3%; 233 of 247) for differentiating between stable and unstable lesions. There was a significant association between grade 3 enhancement and aneurysm instability (P < .0001). Conclusion In patients with intracranial aneurysm, a thick (>1 mm) circumferential pattern of wall enhancement demonstrated the highest specificity for differentiating between stable and unstable aneurysms.

Unruptured intracranial aneurysms: An updated review of current concepts for risk factors, detection and management

The management of patients with unruptured intracranial aneurysms (UIAs) is a complex clinical challenge and constitutes an immense field of research. While a preponderant proportion of these aneurysms never rupture, the consequences of such an event are severe and represent an important healthcare problem. To date, however, the natural history of UIAs is not completely understood and there is no accurate means to discriminate the UIAs that will rupture from those that will not. Yet, a good understanding of the recent evidence and future perspectives is needed when advising a patient with IA to tailor any information to the given patients level of risk and psychoaffective status. Thus, this review addresses the current concepts of epidemiology, risk factors, detection and management of UIAs.

Orolingual and abdominal angioedema post thrombolysis and thrombectomy

A 53-year-old man treated with an angiotensin-converting enzyme (ACE) inhibitor presented with left hemiplegia (NIH Stroke Scale 23). Magnetic resonance angiography revealed a right proximal middle cerebral artery occlusion (figure 1). Thirty minutes after thrombolysis, orolingual swelling was observed. Two hours later, just after mechanical thrombectomy was completed, he developed painful abdominal edema, which improved after icatibant administration (figure 2). Bradykinin-mediated angioedema can be a complication of recombinant tissue plasminogen activator, typically orolingual, with increased risk for patients on ACE inhibitors.1 We speculate that the procedure of thrombectomy, acting as a mechanical stress,2 could have been a triggering factor for the unusual presentation of abdominal edema.