Kamel Boubagra

Reduced CMRO2 and cerebrovascular reserve in patients with severe intracranial arterial stenosis: A combined multiparametric qBOLD oxygenation and BOLD fMRI study

Multiparametric quantitative blood oxygenation level dependent (mqBOLD) magnetic resonance Imaging (MRI) approach allows mapping tissular oxygen saturation (StO2) and cerebral metabolic rate of oxygen (CMRO2). To identify hemodynamic alteration related to severe intracranial arterial stenosis (SIAS), functional MRI of cerebrovascular reserve (CVR BOLD fMRI) to hypercapnia has been proposed. Diffusion imaging suggests chronic low grade ischemia in patients with impaired CVR. The aim of the present study was to evaluate how oxygen parameters (StO2 and CMRO2), assessed with mqBOLD approach, correlate with CVR in patients (n = 12) with SIAS and without arterial occlusion. The perfusion (dynamic susceptibility contrast), oxygenation, and CVR were compared. The MRI protocol conducted at 3T lasted approximately 1 h. Regions of interest measures on maps were delineated on segmented gray matter (GM) of middle cerebral artery territories. We have shown that decreased CVR is spatially associated with decreased CMRO2 in GM of patients with SIAS. Further, the degree of ipsilateral CVR reduction was well‐correlated with the amplitude of the CMRO2 deficit. The altered CMRO2 suggests the presence of a moderate ischemia explained by both a decrease in perfusion and in CVR. CVR and mqBOLD method may be helpful in the selection of patients with SIAS to advocate for medical therapy or percutaneous transluminal angioplasty‐stenting. Hum Brain Mapp 36:695–706, 2015.

The relationship between post-traumatic ossicular injuries and conductive hearing loss: A 3D-CT study

PURPOSE After a trauma, the conductive ossicular chain may be disrupted by ossicular luxation or fracture. Recent developments in 3D-CT allow a better understanding of ossicular injuries. In this retrospective study, we compared patients with post-traumatic conductive hearing loss (CHL) with those referred without CHL to evaluate the relationship between ossicular injuries and CHL. We also assessed the added value of 3D reconstructions on 2D-CT scan to detect ossicular lesions in patients surgically managed. METHODS The CT scans were performed using a 40-section spiral CT scanner in 49 patients with post-traumatic CHL (n=29) and without CHL (n=20). Three radiologists performed independent blind evaluations of 2D-CT and 3D reconstructions to detect ossicular chain injury. We used the t-test to explore differences regarding the number of subjects with ossicular injury in the two groups. We also estimated the diagnostic accuracy and the inter-rater agreement of the 3D-CT reconstructions associated to 2D-CT scan. RESULTS We identified ossicular abnormality in 14 patients out of 29 and in one patient out of 20 in the CHL and non-CHL groups respectively. There was a significant difference regarding the number of subjects with ossicular lesions between the two groups (P≤0.01). The diagnostic sensitivity of 3D-CT reconstructions associated with 2D-CT ranged from 66% to 100% and the inter-reader agreement ranged from 0.85 to 1, depending of the type of lesion. CONCLUSION The relationship between ossicular lesion and the presence of CHL tightly correlated. 3D-CT reconstructions of the temporal bone are useful to assess patients in a post-traumatic context.

Greater occipital nerve MR tractography: Feasibility and anatomical considerations

BACKGROUND AND PURPOSE To assess the feasibility of greater occipital nerve (GON) tractography using a fully automated tractography technique on the whole-neck volume, in comparison with anatomical knowledge. METHODS Healthy subjects were consecutively included in this study if they had no history or symptoms of headache or brain disorder. A 3T MRI scanner with a 32 channel head coil was used. The following parameters for Diffusion Weighed (DWI) were used: b value of 1000 s/mm2, 32 directions, acquired voxel size: 2 mm isotropic. High-Order tractography with the Constrained Spherical Deconvolution (CSD) model was generated. Track-Weighted Imaging (TWI) maps were generated with MRTrix. Two radiologists performed blind evaluations of the GON pathways on TWI maps. RESULTS A total of 20 healthy subjects were included (12 males and eight females, mean age 53.8 years old). In comparison with anatomical atlas, GON complete visualization (from C1-C2 origin to muscular emergence) was possible in 18 out of 20 healthy subjects. In two cases, GON was not visible in the cervical spine foramen. CONCLUSION Tractography through TWI is a feasible technique to accurately depict GON. This technique may appear as a promising technique for therapeutic management of patients with occipital neuralgia.

Facet joint syndrome: from diagnosis to interventional management

Low back pain (LBP) is the most common pain syndrome, and is an enormous burden and cost generator for society. Lumbar facet joints (FJ) constitute a common source of pain, accounting for 15–45% of LBP. Facet joint degenerative osteoarthritis is the most frequent form of facet joint pain. History and physical examination may suggest but not confirm facet joint syndrome. Although imaging (radiographs, MRI, CT, SPECT) for back pain syndrome is very commonly performed, there are no effective correlations between clinical symptoms and degenerative spinal changes. Diagnostic positive facet joint block can indicate facet joints as the source of chronic spinal pain. These patients may benefit from specific interventions to eliminate facet joint pain such as neurolysis, by radiofrequency or cryoablation. The purpose of this review is to describe the anatomy, epidemiology, clinical presentation, and radiologic findings of facet joint syndrome. Specific interventional facet joint management will also be described in detail.Teaching points• Lumbar facet joints constitute a common source of pain accounting of 15–45%.• Facet arthrosis is the most frequent form of facet pathology.• There are no effective correlations between clinical symptoms, physical examination and degenerative spinal changes.• Diagnostic positive facet joint block can indicate facet joints as the source of pain.• After selection processing, patients may benefit from facet joint neurolysis, notably by radiofrequency or cryoablation.

Low-flow vascular malformation Contribution of sequential postcontrast MRI acquisitions

A 50-year-old man was referred for subacute intracranial hypertension. MRI revealed a well-circumscribed lesion in the posterior fossa that was hypointense on T1-weighted imaging and hyperintense on T2-weighted imaging (figure 1, A and E). Cerebral blood volume map and sequential postcontrast T1-weighted images showed progressive increase in the homogeneity of the contrast enhancement, indicating that the lesion had low but substantial flow (figure 1, B–D). Digital subtraction angiography showed a vascular lesion with a central to peripheral pattern of vascularity and absence of early venous return (figure 1, F–H). The lesion was resected. Pathologic examination revealed a capillary-venous malformation (figure 2).1,2 This case highlights that MRI can identify low flow in vascular malformations.

2323 Imagerie cerebrale de perfusion

Objectifs pedagogiques Connaitre les principales techniques d’acquisition en imagerie cerebrale de perfusion. Savoir analyser une cartographie de perfusion cerebrale. Connaitre les principales applications cliniques de l’imagerie cerebrale de perfusion.

NR24 Traumatisme de l’orbite : apports de la TDM helicoidale

Objectifs Illustrer les lesions oculo-orbitaires traumatiques en TDM helicoidale afin de connaitre leur semiologie, leur prise en charge therapeutique et leur degre d’urgence. Materiels et methodes Apres un rappel de l’anatomie oculo-orbitaire, 20 observations sont presentees afin d’illustrer les lesions traumatiques de l’orbite et leur impact sur la prise en charge therapeutique. Resultats Dans un contexte de traumatisme crânio-facial, la TDM helicoidale des orbites est l’examen de choix pour effectuer le bilan lesionnel. Toute suspicion de corps etranger intra-oculaire, toute atteinte de la fonction visuelle et toute suspicion d’incarceration musculaire necessite une TDM helicoidale en urgence pour une prise en charge therapeutique la plus rapide possible. Nous presentons des atteintes du globe oculaire (contusion, plaie sclerale, corps etranger), des parois osseuses et les lesions associees du nerf optique, des muscles oculo-moteurs et de la graisse peri-orbitaire. Pour chaque lesion, nous discutons l’impact des resultats de l’imagerie sur la prise en charge therapeutique. Conclusion Un traumatisme de l’orbite doit etre explore en TDM helicoidale avec des reconstructions axiales, coronales et para-sagittales obliques dans le plan du nerf optique afin de preciser les lesions susceptibles de menacer l’acuite visuelle et la mobilite oculaire qui peuvent imposer un traitement en urgence.

Superficial Siderosis of the Central Nervous System: Typical Features

The cardinal feature of superficial siderosis is progressive hearing impairment (95%). The sensori-neural loss is retrocochlear, can be asymetric, concerning preferably the high tones. A cerebellar syndrom with ataxia is almost as common. Interestingly the vestibulocerebellum is spared and so despite the central nature of the syndrome nystagmus is rare. Pyramidal signs develop in 76% and other features that may occur include dementia (24%) and memory loss, a neurogenic bladder (24%), sensory signs (13%). Anosmia is also reported (17%). Some cases are associated with symptoms suggesting arachnoiditis including neckache, backache, bilateral sciatica. Association with anterior horn cells dysfunction has been reported . Men Introduction