I. Catalaa

Executive dysfunction in adults with moyamoya disease is associated with increased diffusion in frontal white matter

Background and purpose Alteration of the cerebrovascular reserve (CVR) in the frontal lobes has been associated with cognitive dysfunction in adults with moyamoya disease (MMD). Elevation of the apparent diffusion coefficient (ADC) in normal-appearing white matter on conventional MRI may occur as a consequence of chronic haemodynamic failure. In the present study, the authors examined the relation of ADC with CVR and cognitive dysfunction in adults with MMD. Methods The authors measured ADC and CVR in the normal-appearing frontal white matter. CVR was calculated using dynamic susceptibility contrast-enhanced MRI and the acetazolamide challenge. A standardised and validated neuropsychological assessment test battery focusing on executive function was used. Results 14 patients, 9 women and 5 men (mean age 36.6±12.9 years), were included. The authors found executive dysfunction in 7 of 13 tested patients. ADC and CVR were negatively correlated (Spearman coefficient: −0.46; p=0.015). Elevation of ADC predicted executive dysfunction (area under receiver operating characteristic curve (95% CI): 0.85 (0.59 to 1.16); p=0.032). Conclusion Elevation of ADC in the normal-appearing frontal white matter of adults with MMD was associated with reduced CVR and executive dysfunction. This preliminary study suggests that measurement of ADC might be used to detect patients at risk for cerebral ischaemia and cognitive impairment.

Improvement in cognitive function and cerebral perfusion after bur hole surgery in an adult with moyamoya disease. Case report.

Recent studies have suggested that cognitive impairment may be a common complication in adults with moyamoya disease (MMD). However, the mechanisms of cognitive dysfunction have not been clarified. Whether cognitive impairment may occur as a consequence of cerebral hypoperfusion and may improve after revascularization surgery has not been determined. A 39-year-old West Indian woman with subacute dysexecutive cognitive syndrome and no history of stroke was diagnosed with MMD. Magnetic resonance imaging showed an old, small cerebral infarction in the left frontal white matter and no evidence of recent cerebral ischemia. Perfusion MR imaging with acetazolamide challenge demonstrated a reduced cerebrovascular reserve in both frontal lobes. Revascularization with bur hole surgery was performed, which resulted in complete regression of initial cognitive impairment. Improvement in cognitive function correlated with the development of transdural collaterals on angiography and improvement in cerebral perfusion on MR imaging. This case suggests a relationship between cognitive dysfunction and cerebral hypoperfusion in MMD. Cognitive impairment may be potentially reversible after bur hole surgery and cerebral perfusion improvement.

Apport de l’IRM de perfusion et de la spectroscopie dans le diagnostic de toxoplasmose cérébrale atypique

We report an atypical case of cerebral toxoplasmosis (CT) in a 70-year-old woman with a history of breast cancer. Contrast-enhanced computed tomography revealed a single ring-enhancing lesion in the pons with perifocal oedema and mass effect. Toxoplasma encephalitis was suggested by means of diffusion weighted imaging, MR perfusion and MR spectroscopy, leading to the discovery of HIV infection. The patient was put on antitoxoplasma therapy. Subsequent clinical and radiological improvements confirmed the diagnosis.

Bilateral wallerian degeneration of the middle cerebellar peduncles due to unilateral pontine infarction: A morphologic and spectroscopic study

We report the case of a patient with bilateral and symmetrical T2 hyperintensities of the middle cerebellar peduncles. She had a history of left pontine infarction 8 months before. This was attributed to bilateral Wallerian degeneration. MR Spectroscopy showed decreased N-acetyl aspartate/Creatine (NAA/Cr) ratio in the cerebellar peduncles as well as in the whole cerebellum. We hypothesize that this could reflect neuronal degeneration following a stroke.

Imagerie de l’ischémie cérébrale dans les premières heures : scanner

Objectifs pedagogiques La prise en charge des accidents vasculaires cerebraux en phase aigue (3h, 6h, 12h ?) pose deux questions : Quelle imagerie realiser ? Dans quel but ? Resume La prise en charge des patients presentant un accident vasculaire cerebral dans des Stroke Centers evite 56 deces ou handicap sur 1000 patients. Dans une population de 1 million d’habitants dans un pays developpe, 2400 patients presentent un AVC chaque annee, 700 decedent (29 %), 600 sont dependants (25 %). La diminution de la morbi-mortalite dans les Stroke Centers est uniquement liee a une meilleure prise en charge globale des patients independamment de tout traitement curatif de l’AVC. Le developpement de la thrombolyse intra-veineuse dans les 3 heures suivant le debut des symptomes conditionne le type d’imagerie. Les objectifs de l’imagerie de l’AVC en phase aigue sont d’evaluer le degre d’occlusion arterielle, l’importance de l’hypoperfusion, la souffrance cellulaire. L’objectif est de mieux selectionner les patients pour la thrombolyse intra-veineuse mais surtout d’obtenir une meilleure selection des patients et une meilleure evaluation des resultats pour les etudes en cours et futures sur les nouveaux traitements (antiGP Iia IIIb…). L’IRM de diffusion perfusion couplee a l’angioIRM est actuellement consideree comme le gold standard dans les explorations des AVC en phase aigue. Les inconvenients que presente l’IRM sont la longueur de l’examen, la necessite d’une immobilite totale du patient, l’absence de resultat quantitatif de l’imagerie de perfusion. Le developpement des scanners 16 barrettes permet desormais de realiser un scanner de perfusion par injection de 36 CC d’un produit de contraste iode avec une acquisition de 30 a 40 secondes. Un angioscanner est ensuite realise avec une injection de 60 CC de produit de contraste. Le scanner de perfusion permet d’evaluer le volume sanguin cerebral, le debit cerebral et le « time to peak ». La discordance entre le debit sanguin cerebral et le volume sanguin cerebral pourrait correspondre a une evaluation quantitative de la penombre. Les avantages du scanner de perfusion couple a l’angioscanner sont la disponibilite de la machine, la duree tres courte de l’examen et l’aspect quantitatif de l’evaluation du debit du volume sanguin cerebral. Ce type de scanner pourrait etre realise dans chaque unite neurovasculaire et non pas seulement dans les unites neurovasculaires de reference au sein des CHU.

Adrénoleucodystrophie liée à l’X, forme cérébrale de l’adulte: À propos d’un cas

The authors report a case of an X-linked-adrenoleukodystrophy (ALD) in a young adult presenting with hemianopsia. Adult onset cerebral ALD is rare and represents only 3% of cases of ALD. The observation describes clinical data, as well as conventional and spectroscopic MR imaging and related value in prognosis evaluation.Resume Les auteurs rapportent le cas d’une forme cerebrale d’adrenoleucodystrophie (ALD), decouverte chez un adulte jeune a l’occasion d’un bilan realise pour hemianopsie laterale homonyme. La forme cerebrale de l’adulte represente environ 3 % des cas decrits d’ALD. L’observation decrit la presentation clinique, l’imagerie IRM conventionnelle et spectroscopique ainsi que son interet dans la prise en charge du patient.