S. Godon-Hardy

Three-dimensional dynamic time-resolved contrast-enhanced MRA using parallel imaging and a variable rate k-space sampling strategy in intracranial arteriovenous malformations

To evaluate the effectiveness of three‐dimensional (3D) dynamic time‐resolved contrast‐enhanced MRA (TR‐CE‐MRA) using a combination of a parallel imaging technique (ASSET: array spatial sensitivity encoding technique) and a time‐resolved method (TRICKS: time‐resolved imaging of contrast kinetics) and to compare it with 3D dynamic TR‐CE‐MRA using ASSET alone in the assessment of intracranial arteriovenous malformations (AVMs).

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.

Imagerie des métastases intracrâniennes chez l'adulte.

Intracranial metastases account for up to 35% of intracranial tumors in adult. They can involve any part of the central nervous system: brain, meninges and cranial nerves. Any systemic tumor can metastasize to the brain; the most common primaries include lung, breast and melanoma. Imaging plays a major role in the evaluation and management of patients with metastatic brain tumors. This article discusses optimal CT and MR imaging protocols and describes imaging features and distinguishing characteristics of cerebral and meningeal metastases.

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.

Aspects radio cliniques de l’angiopathie cérébrale aiguë réversible

Purpose. To report clinical and imaging features of diffuse cerebral vasoconstriction and to discuss the role of non-invasive imaging modalities for the diagnosis and the follow-up. Patients and methods. Retrospective study including 13 consecutive patients with a diffuse cerebral vasoconstriction. Evaluation of the sensitivity of Doppler US and magnetic resonance angiography for the diagnosis. Results. The diagnosis is based on the association of a thunderclap headache, declenching factors found in 50% of cases and of stenosis involving middle and small cerebra arteries. In some cases cerebral hemorrhage may be present. Discussion. Diffuse cerebral vasoconstriction is a rare cause of thunder clap headhache, which needs to exclude other causes such as subarchnoid hemorrhage from aneurysm rupture. Non contrast CT of the head, frequently normal, may be falsely reassuring. It is therefore necessary to further assess the cerebral arteries to exclude an aneurysm but also to detect the presence of stenoses that would suggest the diagnosis. Non-invasive imaging modalities (MRA and Doppler US) are favored for detection and follow-up of proximal lesions.

Hemorragie sous-arachnoidienne

Objectifs pedagogiques Connaitre les avantages et les limites du scanner et de l’IRM pour le diagnostic de l’hemorragie sous-arachnoidienne. Connaitre le protocole d’IRM le plus adapte pour le diagnostic aux phases aigues et sub-aigues de l’hemorragie sous-arachnoidienne. Connaitre la valeur de l’angio-scanner et de l’angio-IRM pour le diagnostic etiologique et preciser la conduite a tenir en cas de bilan vasculaire normal. Preciser les parametres radiologiques pronostiques. Messages a retenir Une cephalee en coup de tonnerre est le signe revelateur habituel de l’hemorragie sous-arachnoidienne mais des tableaux trompeurs existent. La sensibilite diagnostique du scanner decroit avec le temps. La sequence FLAIR est superieure au scanner en particulier pour les hemorragies de petite abondance ou vues au-dela de la premiere semaine. La sensibilite diagnostique de la ponction lombaire est proche de 100 % entre la douzieme heure et le quinzieme jour apres le saignement. L’abondance de l’hemorragie, un hematome cerebral associe, une hydrocephalie, sont de mauvais pronostics. Les anevrismes de moins de 3 mm restent difficiles a mettre en evidence, en angio-IRM ou angio-scanner.

MR imaging of the brain and spinal cord in lymphomatoid granulomatosis: A case report and review of the literature

Journal of Neuroradiology - In Press.Proof corrected by the author Available online since samedi 6 avril 2013

NR2 ARM dynamique 3D en exploration intracranienne : technique, indications, images pieges

Objectifs Presenter les bases techniques, applications cliniques, pieges et artefacts de l’ARM dynamique 3D en exploration intracrâ-nienne. Materiels et methodes Les techniques recentes d’ARM dynamique combinent une ARM rapide avec une technique d’imagerie parallele permettant de concilier un temps d’acquisition court, une resolution spatiale importante et une acquisition volumique. Elle est utilisee dans les malformations vasculaires intracrâniennes (MAV, fistule durale, anevrisme) et les tumeurs en complement des cartographies de perfusion. Resultats Avec une resolution temporelle de 1 seconde, l’ARM dynamique permet de separer les differents compartiments constituant les malformations vasculaires intracrâniennes (afferences, nidus et efferences) et les veines de drainage des veines normales. Elle s’affranchit d’images pieges liees a un hematome ou a une prise de contraste post-therapeutique grâce a la soustraction d’un masque. Neanmoins, l’acquisition non isotropique a l’origine d’artefacts de volume partiel et le temps d’acquisition superieur a 500 ms, ne lui permettent pas de se substituer entierement a l’angiographie numerisee. Conclusion L’apport essentiel de la sequence d’ARM 3D presentee est une information dynamique qui est en fait une alternative non invasive a l’angiographie numerisee dans le diagnostic et le suivi post-therapeutique des malformations vasculaires intracrâniennes et des tumeurs.

Angiopathie cerebrale aigue benigne. A propos de 11 cas

Objectifs Presenter les aspects radiocliniques de l’angiopathie cerebrale aigue benigne (ACAB). Preciser la place de l’IRM/ARM dans le diagnostic de cette entite rare. Materiels et methodes Etude retrospective de 11 cas d’ACAB. Ont ete analyses : le terrain (migraine, tabac, HTA), les facteurs declenchants (post-partum, effort, prise de toxique, stress) et les anomalies retrouvees a l’IRM (anomalies des vaisseaux et du parenchyme, hemorragie meningee), le delai de reversibilite des lesions. Ces resultats ont ete correles aux donnees de la litterature. Resultats La symptomatologie inaugurale est dominee par des cephalees explosives repetitives (n = 10/11). Un facteur declenchant est retrouve dans 5 cas. L’examen clinique est normal chez 6 patients (deficit n = 2, raideur meningee n = 3). En imagerie, on note : la presence de stenoses des arteres intracrâniennes de moyen calibre situees sur les axes anterieurs +/-posterieur, un hematome (n = 2), une hemorragie meningee focale (n = 3), des anomalies de la substance blanche sous corticale (n = 2). Le bilan biologique est normal. Le delai de reversibilite des lesions sur le suivi en IRM/ARM est de 1 a 5 semaines. Conclusion L’ACAB est une cause rare de cephalees aigues. L’IRM permet d’en faire le diagnostic et d’eliminer les causes plus frequentes : rupture d’anevrisme, thrombophlebite.

NR37 Guide d’interpretation de l’ARM 3D temps de vol des arteres intracraniennes

Objectifs Proposer un outil pedagogique permettant une initiation et un perfectionnement de l’interpretation de l’ARM temps de vol (3D TOF) des arteres intracrâniennes. Materiels et methodes Des explorations normales et les observations cliniques les plus significatives ont ete recueillies afin d’illustrer un guide d’apprentissage interactif. Resultats Le guide est organise en cinq parties, consacrees : 1) aux problemes techniques et modes de reconstructions ; 2) a l’anatomie normale et aux variantes anatomiques habituellement rencontrees (hypoplasies et agenesies, persistance d’anastomoses embryonnaires, reseau de suppleance) ; 3) a l’expose d’un schema de lecture systematisee ; 4) aux pieges diagnostiques ; 5) et a la semiologie des pathologies les plus frequentes (stenose, occlusion, anevrisme, spasme, dissection, malformation et fistule arterioveineuses). Conclusion L’ARM temps de vol est une technique d’examen quotidienne. Elle fait partie des protocoles d’exploration proposes devant des motifs de consultation extremement frequents tels que les cephalees, les syndromes meninges et les deficits neurologiques. La lecture systematisee de cet examen est indispensable pour le diagnostic des affections neurovasculaires et le bilan des lesions de la base du crâne.