F. Clarençon

Reasoning by analogy requires the left frontal pole: lesion-deficit mapping and clinical implications

SEE BURGESS DOI101093/BRAIN/AWW092 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE  : Analogical reasoning is at the core of the generalization and abstraction processes that enable concept formation and creativity. The impact of neurological diseases on analogical reasoning is poorly known, despite its importance in everyday life and in society. Neuroimaging studies of healthy subjects and the few studies that have been performed on patients have highlighted the importance of the prefrontal cortex in analogical reasoning. However, the critical cerebral bases for analogical reasoning deficits remain elusive. In the current study, we examined analogical reasoning abilities in 27 patients with focal damage in the frontal lobes and performed voxel-based lesion-behaviour mapping and tractography analyses to investigate the structures critical for analogical reasoning. The findings revealed that damage to the left rostrolateral prefrontal region (or some of its long-range connections) specifically impaired the ability to reason by analogies. A short version of the analogy task predicted the existence of a left rostrolateral prefrontal lesion with good accuracy. Experimental manipulations of the analogy tasks suggested that this region plays a role in relational matching or integration. The current lesion approach demonstrated that the left rostrolateral prefrontal region is a critical node in the analogy network. Our results also suggested that analogy tasks should be translated to clinical practice to refine the neuropsychological assessment of patients with frontal lobe lesions.

Transvenous embolization of an intraorbital arteriovenous fistula using Onyx

We report a 61-year-old male with an intraorbital arteriovenous fistula. Due to the close proximity of the arterial feeder to the central retinal artery, and the tiny calibre of the draining branches of the superior ophthalmic vein, transvenous embolization of the fistula by Onyx was preferred. The procedure completely obliterated the shunt and the patient had complete relief of symptoms within 6 months.

Imaging findings of intraventricular and ependymal lesions.

Intraventricular and ependymal lesions comprise a wide spectrum of tumoral, cystic, vascular, infectious and inflammatory disorders. With respect to tumoral and cystic diseases, the location, age and CT and MRI patterns are the main factors for diagnosis. The MRI findings of infectious diseases are supported by the clinical history, immune status and laboratory findings. Intracranial associated lesions may be very helpful for the diagnosis of Sturge-Weber, subependymal giant cell astrocytoma and systemic diseases, such as sarcoidosis and histiocytosis. Intraventricular vascular lesions are rare but present typical features on neuroimaging. The aim of this review is to provide a detailed description of these disorders with an emphasis on the key imaging findings and to generate a narrow differential diagnosis. We present a diagnostic approach based on the solid or cystic aspect of the intraventricular focal mass, its origin from the ventricular wall or choroid plexus and its location within the ventricular system. We also propose a differential diagnosis for ependymal dissemination: the ependymal enhancement may be due to ventriculitis from adjacent parenchymal lesions, the ependymal spread of tumors or infectious or inflammatory/systemic diseases.

MRI and FDG PET/CT findings in a case of probable Heidenhain variant Creutzfeldt-Jakob disease.

Creutzfeldt-Jakob disease (CJD) is a neurodegenerative disease caused by the accumulation of a pathogenic isoform of a prion protein in neurons that is responsible for subacute dementia. The Heidenhain variant is an atypical form of CJD in which visual signs are predominant. This is a report of the case of a 65-year-old man with probable CJD of the Heidenhain variant, with topographical concordance between findings on magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose (FDG) photopenic areas on positron emission tomography (PET)/computed tomography (CT) for cortical parietooccipital lesions.

Thrombectomy for acute basilar artery occlusion by using double Merci retriever devices and bilateral temporary vertebral artery flow reversal. Technical note.

Basilar artery occlusion is a dramatic clinical event with a high mortality rate if patients are treated by standard medical therapy, including anticoagulation agents. The use of intravenous tissue plasminogen activator or intraarterial thrombolysis recanalizes 30-53 and 64%, respectively, of patients with basilar stroke. Mechanical endovascular treatments allow tailored procedures with quicker results and higher recanalization rates. The authors describe a successful mechanical removal of an obstruction in an acute occlusion of the basilar artery tip involving both proximal segments of posterior cerebral arteries in a 20-year-old man. They used 2 Merci retriever devices at the same time, and performed bilateral proximal vertebral artery occlusion for temporary flow reversal and aspiration.

Neuroimaging features in posterior reversible encephalopathy syndrome: A pictorial review

Posterior reversible encephalopathy syndrome (PRES) is a radioclinical entity associating nonspecific neurological symptoms (headache, seizures, impairment of alertness, visual disturbances…) occurring in evocative clinical condition (hypertension, eclampsia, immunosuppressor agents, systemic lupus erythematosus…). In the acute stage, the typical imaging finding is a vasogenic edema predominant in the subcortical parietal-occipital white matter. The purpose of this pictorial review is to illustrate the different neuroimaging features of PRES and present key radiological elements to assert diagnosis. In this overview, we examine the following points: the distributions of vasogenic edema, hemorrhage, the varying patterns in diffusion and perfusion, the different types of enhancement encountered and the vascular modifications demonstrated by angiography. The cause of PRES is still unknown. Nevertheless, catheter angiography, MR angiography and MR perfusion features in PRES render further insight into its pathophysiology. Follow-up imaging shows evidence of radiologic improvement in the very large majority of cases in 1 or 2weeks, sometimes in up to 1month. Recurrent PRES attacks are uncommon. Atypical imaging presentation should not reject the diagnosis of PRES in a compatible clinical situation.

Flow Diversion versus Standard Endovascular Techniques for the Treatment of Unruptured Carotid-Ophthalmic Aneurysms.

BACKGROUND AND PURPOSE: Over the past few years, flow diversion has been increasingly adopted for the treatment of intracranial aneurysms, especially in the paraclinoid and paraophthalmic carotid segment. We compared clinical and angiographic outcomes and complication rates in 2 groups of patients with unruptured carotid-ophthalmic aneurysms treated for 7 years by either standard coil-based techniques or flow diversion. MATERIALS AND METHODS: From February 2006 to December 2013, 162 unruptured carotid-ophthalmic aneurysms were treated endovascularly in 138 patients. Sixty-seven aneurysms were treated by coil-based techniques in 61 patients. Flow diverters were deployed in 95 unruptured aneurysms (77 patients), with additional coiling in 27 patients. Complication rates, clinical outcome, and immediate and long-term angiographic results were retrospectively analyzed. RESULTS: No procedure-related deaths occurred. Four procedure-related thromboembolic events (6.6%) leading to permanent morbidity in 1 case (1.6%) occurred in the coiling group. Neurologic complications were observed in 6 patients (7.8%) in the flow-diversion group, resulting in 3.9% permanent morbidity. No statistically significant difference was found between complication (P = .9) and morbidity rates (P = .6). In the coiling group (median follow-up, 31.5 ± 24.5 months), recanalization occurred at 1 year in 23/50 (54%) aneurysms and 27/55 aneurysms (50.9%) at the latest follow-up, leading to retreatment in 6 patients (9%). In the flow-diversion group (mean follow-up, 13.5 ± 10.8 months), 85.3% (35/41) of all aneurysms were occluded after 12 months, and 74.6% (50/67) on latest follow-up. The retreatment rate was 2.1%. Occlusion rates between the 2 groups differed significantly at 12 months (P < .001) and at the latest follow-up (P < .005). CONCLUSIONS: Our retrospective analysis shows better long-term occlusion of carotid-ophthalmic aneurysms after use of flow diverters compared with standard coil-based techniques, without significant differences in permanent morbidity.

Distant and delayed (>7 days) hemorrhage after treatment by flow-diverter stents in intracranial aneurysms: a rare but potentially serious complication.

In a recent meta-analysis, intraparenchymal hemorrhage secondary to treatment by a flow-diverter stent (FDS) was reported in 3% of the cases.[1][1] Most of these hemorrhages were periprocedural complications. More surprising cases of delayed ipsilateral hemorrhage have been reported lately in

Spastic paraparesis as a manifestation of Leber's disease.

Sirs: Leber’s hereditary optic neuropathy (LHON) is a genetic disease due to mutations in mitochondrial DNA (mtDNA) responsible for central, bilateral, painless, and fast progressive visual loss with optic nerve atrophy. Various extra-ocular manifestations, called Leber’s “plus” syndrome, have been described [4]. They include a multiple sclerosis-like syndrome, cerebellar ataxia, Leigh-like encephalopathy, dystonia, and Parinaud’s syndrome [2, 4, 5]. We report a patient harbouring the 11778 mtDNA mutation who presented with progressive spastic paraparesis (PSP) and delayed optic nerve involvement. A 34-year-old man attended our department for recent worsening of painful leg stiffness that had been present for at least 3 years and the occurrence of sexual and urinary disturbances (dysuria). Personal past medical history included 2 generalized epileptic seizures during childhood without any recurrence under phenobarbital. His maternal grandmother, his mother, three uncles and three brothers (Fig. 1) were known for having LHON disease (11778 mutation of mtDNA), revealed by an optic nerve involvement. Neurological examination revealed spasticity and symmetric exaggerated reflexes in the lower limbs, and bilateral Babinski’s sign without motor weakness or sensory abnormalities. Visual acuity was normal. Cervical, dorsal and lumbar contrast-enhanced magnetic resonance imaging (MRI) was normal. Brain MRI showed slight white matter hypertensities in the posterior regions on FLAIR sequences. Blood glucose, electrolytes, urea, ESR and coagulation tests were normal. Antinuclear antibodies, neutrophil antinuclear cytoplasm antibodies, rheumatoid factor, blood cultures, very long chain fatty acids, B12 vitamin, folates, lactates and pyruvates were all in the normal ranges. Serum tests for Mycobacterium tuberculosis, Borrelia burgdorferi, herpes viruses, HTLV-1 and 2, HIV, hepatitis B and C, enterovirus (echovirus and coxsackie), TPHA, VDRL, were all negative. Analysis of cerebrospinal fluid (CSF) showed 1/mm3 white cells, CSF glucose was 3.7 mmol/L and protein was 0.31 g/L with normal immunoelectrophoresis. The optic discs were normal on fundoscopy examination. Visual evoked potentials (VEP) revealed an increase in the P100 latency at 150 ms on the right eye. Mitochondrial DNA test showed a homoplasmic 11778 mtDNA mutation. Muscular 31Phosphorus magnetic resonance spectroscopy (31PMRS) was normal. A treatment by idebenone (90 mg t. i. d.) was started, with no clinical significant improvement six months later We report a PSP patient harbouring the LHON 11778 mtDNA mutation. Although the causal relationship remains uncertain, we did not find any other inflammatory, infectious, vascular, compressive or metabolic explanation. To our knowledge, only one case of 11778 mtDNA mutation Leber’s “plus” syndrome with PSP has been previously reported [1]. In contrast to our case, the previous case had a visual involvement when paraparesis was diagnosed. Moreover, T2weighted MRI showed periventricular hyperintensities. Muscular and cerebral 31PMRS were abnormal and treatment by idebenone led to a clinical improvement that correlated with the 31PMRS modifications. No lumbar puncture was done. In fact, the remittent evolution and MRI abnormalities may suggest that the patient had a MSlike syndrome, the most frequently described Leber’s plus syndrome [5]. Here, we did not find any significant abnormalities at muscular 31PMRS either, a test which is thought to be able to detect cellular metabolic dysfunctions [3]. The LETTER TO THE EDITORS

Caution; Confusion Ahead…

We read with great interest the article entitled “Endovascular Therapy of M2 Occlusion in IMS III: Role of M2 Segment Definition and Location on Clinical and Revascularization Outcomes” by Tomsick et al.[1][1] This study is a post hoc subgroup analysis of the patients randomized in the