Justification des demandes de tomodensitométrie aux urgences

Introduction : La justification des demandes de tomodensitométrie (TDM) faites aux urgences est mal connue. Notre objectif était d’évaluer la justification des demandes de TDM dans un service d’urgences adultes.

Méthodes : La justification des demandes de scanner a été mesurée prospectivement de deux façons complémentaires. L’adéquation aux recommandations a été évaluée pour l’ensemble des demandes de TDM par confrontation à une liste préétablie de syndromes et d’hypothèses diagnostiques. La pertinence des demandes a été évaluée par un comité d’experts sur la base du dossier médical des urgences pour 100 de ces dossiers.

Résultats : Les 273 TDM incluses concernaient le crâne (52%), l’abdomen (17%), le thorax (11%) ou une autre localisation (20%). Elles étaient en adéquation avec les recommandations dans 215 cas (79%). Pour 100 dossiers analysés par le comité d’experts, la pertinence a été adjugée à l’unanimité pour 95 cas ; 67 TDM (71%) ont été jugées pertinentes. La concordance entre l’adéquation aux recommandations et la pertinence évaluée par le comité d’expert était faible (kappa, 0,27, intervalle de confiance à 95%, de 0,06 à 0,47). Le seul facteur associé significativement à la pertinence était l’opinion du clinicien en charge du patient que la TDM ne pouvait pas être reportée (OR=6,7 avec IC95% [1,6-28,1], p=0,01).

Conclusion : La proportion des demandes de TDM qui ne sont pas en adéquation avec les recommandations et la proportion de demandes non pertinentes sont élevées. Elles suggèrent que le nombre de TDM demandées par les services d’urgences pourrait être diminué.

Anti-CEA Pretargeted Immuno-PET Shows Higher Sensitivity Than DOPA PET/CT in Detecting Relapsing Metastatic Medullary Thyroid Carcinoma: Post Hoc Analysis of the iPET-MTC Study

Pretargeting parameters for the use of anti-carcinoembryonic antigen (CEA) bispecific monoclonal antibody TF2 and the ⁶⁸Ga-labeled IMP288 peptide for immuno-PET have been optimized in a first-in-humans study performed on medullary thyroid carcinoma (MTC) patients (the iPET-MTC study). The aim of this post hoc analysis was to determine the sensitivity of immuno-PET in relapsing MTC patients, in comparison with conventional imaging and ¹⁸F-l-dihydroxyphenylalanine (¹⁸F-DOPA) PET/CT. Methods: Twenty-five studies were analyzed in 22 patients. All patients underwent immuno-PET 1 and 2 h after ⁶⁸Ga-IMP288 injection pretargeted by TF2, in addition to neck, thoracic, abdominal, and pelvic CT; bone and liver MRI; and ¹⁸F-DOPA PET/CT. The gold standard was histology or confirmation by one other imaging method or by imaging follow-up. Results: In total, 190 lesions were confirmed by the gold standard: 89 in lymph nodes, 14 in lungs, 46 in liver, 37 in bone, and 4 in other sites (subcutaneous tissue, heart, brain, and pancreas). The number of abnormal foci detected by immuno-PET was 210. Among these, 174 (83%) were confirmed as true-positive by the gold standard. Immuno-PET showed a higher overall sensitivity (92%) than ¹⁸F-DOPA PET/CT (65%). Regarding metastatic sites, immuno-PET had a higher sensitivity than CT, ¹⁸F-DOPA PET/CT, or MRI for lymph nodes (98% vs. 83% for CT and 70% for ¹⁸F-DOPA PET/CT), liver (98% vs. 87% for CT, 65% for ¹⁸F-DOPA PET/CT, and 89% for MRI), and bone (92% vs. 64% for ¹⁸F-DOPA PET/CT and 86% for MRI), whereas sensitivity was lower for lung metastases (29% vs. 100% for CT and 14% for ¹⁸F-DOPA PET/CT). Tumor SUV_max at 60 min ranged from 1.2 to 59.0, with intra- and interpatient variability. Conclusion: This post hoc study demonstrates that anti-carcinoembryonic antigen immuno-PET is an effective procedure for detecting metastatic MTC lesions. Immuno-PET showed a higher overall sensitivity than ¹⁸F-DOPA PET/CT for disclosing metastases, except for the lung, where CT remains the most effective examination.

The vestibulocochlear nerve (VIII)

The vestibulocochlear nerve (8th cranial nerve) is a sensory nerve. It is made up of two nerves, the cochlear, which transmits sound and the vestibular which controls balance. It is an intracranial nerve which runs from the sensory receptors in the internal ear to the brain stem nuclei and finally to the auditory areas: the post-central gyrus and superior temporal auditory cortex. The most common lesions responsible for damage to VIII are vestibular Schwannomas. This report reviews the anatomy and various investigations of the nerve.

The lower cranial nerves: IX, X, XI, XII

The lower cranial nerves innervate the pharynx and larynx by the glossopharyngeal (CN IX) and vagus (CN X) (mixed) nerves, and provide motor innervation of the muscles of the neck by the accessory nerve (CN XI) and the tongue by the hypoglossal nerve (CN XII). The symptomatology provoked by an anomaly is often discrete and rarely in the forefront. As with all cranial nerves, the context and clinical examinations, in case of suspicion of impairment of the lower cranial nerves, are determinant in guiding the imaging. In fact, the impairment may be located in the brain stem, in the peribulbar cisterns, in the foramens or even in the deep spaces of the face. The clinical localization of the probable seat of the lesion helps in choosing the adapted protocol in MRI and eventually completes it with a CT-scan. In the bulb, the intra-axial pathology is dominated by brain ischemia (in particular, with Wallenberg syndrome) and multiple sclerosis. Cisternal pathology is tumoral with two tumors, schwannoma and meningioma. The occurrence is much lower than in the cochleovestibular nerves as well as the leptomeningeal nerves (infectious, inflammatory or tumoral). Finally, foramen pathology is tumoral with, outside of the usual schwannomas and meningiomas, paragangliomas. For radiologists, fairly hesitant to explore these lower cranial pairs, it is necessary to be familiar with (or relearn) the anatomy, master the exploratory technique and be aware of the diagnostic possibilities.

Facial nerve: from anatomy to pathology

The facial nerve (CN VII) emerges from the facial nerve nucleus in the pons. It is accompanied by CN VIII along its cisternal pathway, as well as at the internal auditory meatus. Its petrous pathway includes a labyrinthine segment, a horizontal tympanic segment and a vertical mastoid segment until the stylomastoid foramen. It then continues to the parotid gland. Pontine impairment is usually associated with other neurological symptoms. Lesions of the cerebellopontine angle (most often meningioma and schwannoma) initially result in impairment of CN VIII. The impairment of CN VII takes second place. Peripheral impairment (outside of a traumatic context) is most often due to Bell's palsy.

Vascular malformations of the brain

Pediatric neurovascular malformations are rare. However, proper diagnosis and management are mandatory to achieve a good neurocognitive outcome. Among them several types can be identified with specificities for each. In the newborn and infancy, the most frequent cerebral venous malformation is vein of Galen aneurysmal malformation. It can be discovered antenatally, in neonates (mainly in cases with hemodynamic impact), or in infants presenting with macrocrania and hydrocephalus. Treatment of choice is endovascular, by transarterial selective occlusion of pathological vessels. Interventions are staged with a first session at around 5 months, adjusted to neurological development. Late consequences, especially if left untreated or treated outside the therapeutic window, are delayed neurocognitive development and seizures. Pial arteriovenous malformation can also be diagnosed antenatally. Regional parenchymal destruction could occur in the first months of life, requiring early endovascular treatment. Dural sinus malformations are the third main type of neurovascular malformation, and are also diagnosed antenatally or in the first months of life. Cardiac tolerance is usually good. Adverse consequences are mainly neurocognitive delay due to chronic venous hyperpressure or acute hemorrhage due to thrombosis of the pathological sinuses. Nidal-type brain arteriovenous malformation and cavernous angioma are usually seen later in children, with hemorrhage often being the first presenting symptom.

Infectious and metabolic brain imaging

Central nervous system infectious and metabolic disease is a vast domain. We have chosen to focus particularly on five pathological conditions: brain abscess, herpes encephalitis, Creutzfeldt-Jacob disease, posterior reversible encephalopathy and central pontine myelinolysis. We will pay particular attention to MRI signs and the specific sequences to use in each condition, in addition to the conventional sequences, in order to avoid diagnostic traps. Once the MRI exploration is complete, the diagnosis still cannot be established without knowing the clinical and metabolic context.

Relationship between IDH1 mutation status and magnetic resonance imaging features in WHO grade II and III oligodendroglial tumors

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Background: In gliomas, relationship between radiological characteristics and several biomarkers was the subject of numerous publications. Mutations in the isocitrate dehydrogenase 1 (IDH1) gene have been identified recently to play a key role in these tumors occuring in up to 75% of low-grade diffuse (WHO grade II) and anaplastic (WHO grade III) astrocytic, oligodendroglial and mixed oligodendroglial neoplasms. However, the correlation with magnetic resonance imaging (MRI) features has been little studied. Methods: Patients treated for WHO grade II and III oligodendroglial tumors between 2005 and 2011 were retrospectively identified. Each case has been reviewed by the same neuropathologist. IDH1 and IDH2 mutations were available. Preoperative MRI, including T1 weighted, T2 weighted, T1 contrast enhanced, FLAIR, T2* weighted, diffusion weighted (ADC ratio), perfusion weighted (CBV ratio) and MR spectroscopy, were analyzed by two radiologists blinded from molecular data. Logistic regression analysis and Fisher’s test were used to develop predictive models of genetic profile from imaging. Results: Sixty eight patients, WHO grade II (n= 37) and grade III (n=31) patients were identified. Mean age at diagnosis was 46 years; ratio male/female was 40/28. IDH1 mutations were identified in 42 patients (62 %), IDH2 in 4 patients (6 %). Analysis of tumor location, size, borders, morphological aspect, and signal did not shown any significant difference between IDH1 mutated group and IDH1 non mutated group neither in grade II nor in grade III oligodendroglial tumors. In the same way, MR spectroscopy (Choline/NAA ratio and detection of lipid and lactate) was not relevant to discern the two groups. As well, ADC ratio (1,5 versus 1,4; p=0,35) and CBV ratio (3,4 versus 4,2; p= 0,46) did not reveal any difference between mutated group and non mutated group. Conclusions: In our study, IDH1 mutations were not correlated with MRI features available during routine MRI. Nevertheless, recent studies suggest the ability of MR spectroscopy to detect 2-hydroxyglutarate as an MRI marker of IDH1 mutated tumors, which encourage carrying on research in molecular imaging.

Paediatric moyamoya in mainland France: a comprehensive survey of academic neuropaediatric centres

BACKGROUND

Epidemiological data of paediatric moyamoya disease/syndrome (MMD/MMS) in non-Asian populations are scarce.

METHODS

A questionnaire was sent to every French neuropaediatric academic centre to estimate the prevalence, incidence, familial form rate and location of paediatric MMD/MMS cases. Specific paediatric data were also retrieved from the most recent nationwide Japanese study.

RESULTS

A 100% response rate was obtained. The prevalence of paediatric MMD/MMS was estimated at 0.39/100,000 children (95% CI: 0.28-0.49), and the incidence was estimated at 0.065/100,000 children/year (95% CI: 0.025-0.12), with 7.5% familial cases. The prevalence was homogenous within the different administrative areas.

CONCLUSIONS

This comprehensive survey of MMD/MMS in academic neuropaediatric centres suggests that the prevalence of the disease in children in France is approximately 1/20th of that estimated in Asia.

Pathomechanisms of Symptomatic Developmental Venous Anomalies

Background and Purpose— Although it is generally accepted that developmental venous anomalies (DVAs) are benign vascular malformations, over the past years, we have seen patients with symptomatic DVAs. Therefore, we performed a retrospective study and a literature study to review how, when, and why DVAs can become clinically significant.

Methods— Charts and angiographic films of 17 patients with DVAs whose 18 vascular symptoms could be attributed to a DVA were selected from a neurovascular databank of our hospital. MRI had to be available to rule out any other associated disease. In the literature, 51 cases of well-documented symptomatic DVAs were found. Pathomechanisms were divided into mechanical and flow-related causes.

Results— Mechanical (obstructive or compressive) pathomechanisms accounted for 14 of 69 symptomatic patients resulting in hydrocephalus or nerve compression syndromes. Flow-related pathomechanisms (49 of 69 patients) could be subdivided into complications resulting from an increase of flow into the DVA (owing to an arteriovenous shunt using the DVA as the drainage route; n=19) or a decrease of outflow (n=26) or a remote shunt with increased venous pressure (n=4) leading to symptoms of venous congestion. In 6 cases, no specific pathomechanisms were detected.

Conclusions— Although DVAs should be considered benign, under rare circumstances, they can be symptomatic. DVAs, as extreme variations of normal venous drainage, may represent a more fragile venous drainage system that can be more easily affected by in- and outflow alterations. The integrity of the DVA needs to be preserved irrespective of the treatment that should be tailored to the specific pathomechanism.

Dural arteriovenous shunts: a new classification of craniospinal epidural venous anatomical bases and clinical correlations

BACKGROUND AND PURPOSE

The craniospinal epidural spaces can be categorized into 3 different compartments related to their specific drainage role of the bone and central nervous system, the ventral epidural, dorsal epidural, and lateral epidural groups. We propose this new classification system for dural arteriovenous shunts and compare demographic, angiographic, and clinical characteristics of dural arteriovenous shunts that develop in these 3 different locations.

METHODS

Three hundred consecutive cases (159 females, 141 males; mean age: 47 years; range, 0 to 87 years) were reviewed for patient demographics, clinical presentation, multiplicity, presence of cortical and spinal venous reflux, and outflow restrictions and classified into the 3 mentioned groups.

RESULTS

The ventral epidural group (n=150) showed a female predominance, more benign clinical presentations, lower rate of cortical and spinal venous reflux, and no cortical and spinal venous reflux without restriction of the venous outflow. The dorsal epidural group (n=67) had a lower mean age and a higher rate of multiplicity. The lateral epidural group (n=63) presented later in life with a male predominance, more aggressive clinical presentations, and cortical and spinal venous reflux without evidence of venous outflow restriction. All differences were statistically significant (P<0.001).

CONCLUSIONS

Dural arteriovenous shunts predictably drain either in pial veins or craniofugally depending on the compartment involved by the dural arteriovenous shunt. Associated conditions (outflow restrictions, high-flow shunts) may change that draining pattern. The significant differences between the groups of the new classification support the hypothesis of biological and/or developmental differences in each epidural region and suggest that dural arteriovenous shunts are a heterogeneous group of diseases.

Patterns of the Cranial Venous System from the Comparative Anatomy inVertebrates. Part III. The Ventricular System and Comparative Anatomy of the Venous Outlet of Spinal Cord and Its Homology with the Five Brain Vesicles

SUMMARY

Ontogenetically, the ventricular venous systemmay develop in order to drain the gray matter(cells of the mantle layer of the neural tube) which migrates dorsally. On primitive brain vesicles of submammals especially fish, amphibianand reptile, the ventricular venous system is the major venous collector located on the middorsal surface, in between the meningeal layers comparable to the subarachnoid space in mammals. The ventricular venous system functions as a major drainage system for the brain vesicles in these submammals but its role decreases when the other two venous systems develop. Concerning the route of venous exit from the brain vesicles, we found that it resembles the spinal cord but could not be found all the way along the brain vesicles.

Patterns of the Cranial Venous System from the Comparative Anatomy in Vertebrates. Part II.The Lateral-Ventral Venous System

SUMMARY

Comparing the adult submammalian brain with the human embryonic brain, some patterns of venous drainage are quite similar. The veins lying on the lateral surface of the brain in submammals resemble those of the human embryo. In addition, the new longitudinal venous anastomosis ventral to the brain vesicles occurring late in human embryonic development seems to be similar to the late appearance of the basal vein and the ventral brain stem venous plexus found in adult mammals including man. The evolution of the new structures of the brain vesicles throughout the vertebrate series may have an induction role on the appearance of the cranial venous system. This part of the article series focuses on the evolution of the lateral-ventral venous system of the five brain vesicles. Nevertheless, the limitation of this article is due in part to the paucity of circumstantial papers and different names used for the veins.

White matter abnormalities in mild traumatic brain injury: a diffusion tensor imaging study

BACKGROUND AND PURPOSE

Traumatic axonal injury is a primary brain abnormality in head trauma and is characterized by reduction of fractional anisotropy (FA) on diffusion tensor imaging (DTI). Our hypothesis was that patients with mild traumatic brain injury (TBI) have widespread brain white matter regions of reduced FA involving a variety of fiber bundles and show fiber disruption on fiber tracking in a minority of these regions.

MATERIALS AND METHODS

Ethics committee approval and informed consent were obtained. Twenty-one patients with mild TBI were investigated (men:women, 12:9; mean age +/- SD, 32 +/- 9 years). In a voxel-based comparison with 11 control subjects (men:women, 8:3; mean age, 37 +/- 9 years) using z score analysis, patient regions with abnormally reduced FA were defined in brain white matter. MR imaging, DTI, and fiber tracking characteristics of these regions were described and analyzed using Pearson correlation, linear regression analysis, or the chi(2) test when appropriate.

RESULTS

Patients had on average 9.1 regions with reduced FA, with a mean region volume of 525 mm(3), predominantly found in cerebral lobar white matter, cingulum, and corpus callosum. These regions mainly involved supratentorial projection fiber bundles, callosal fibers, and fronto-temporo-occipital association fiber bundles. Internal capsules and infratentorial white matter were relatively infrequently affected. Of all of the involved fiber bundles, 19.3% showed discontinuity on fiber tracking.

CONCLUSION

Patients with mild TBI have multiple regions with reduced FA in various white matter locations and involving various fiber bundles. A minority of these fiber bundles show discontinuity on fiber tracking.

[Arterial ischemic stroke in the healthy child. Practical approach (neonate and foetus excluded)]

Primary stroke can be due to embolism or an obstructive process of the vascular wall. Embolism may come from a parietal lesion of a large artery in the neck (traumatic dissections), from a cryptic cardiopathy, from a venous thrombosis associated with a right-left shunt. Among pathologies of endocranial arteries, the most frequent is the acute, postviral arteriopathy of the sus-clinoïd carotid, which evolves toward stabilisation or regression. Insidious obstructive arteriopathies of the Willis circle, including development of a transparenchymal suppletive circulation (Moya-Moya disease), cumulate chronic circulatory insufficiency and repetitive strokes. Inflammatory multifocal cerebral arteriopathies mainly involve mean and small arteries. Most of them are secondary to a multisystemic disease, but some are primary. The basic investigation is anatomical and begins with MRI. Emergency conventional cerebral angiography is discussed when heparinotherapy is difficult to decide (evolutive thrombosis), or when an endovascular intervention appears possible (anoeuvrism). Secondarily, conventional angiography is indicated in any chronic situation where a precise anatomical follow-up is necessary. Investigations of the cardiovascular system, of the thrombophilic risk, of a dysimmune process are discussed according to the clinico-anatomical diagnosis.

Extracranial vertebral artery involvement in neurofibromatosis type I. Report of four cases and literature review

SUMMARY

Neurofibromatosis type 1 (NF-1) is one of the most common inherited diseases and as an autosomal dominant genetic disorder results from NF-1 gene mutation with 100% penetration and wide phenotypic variability. The disease can involve a wide variety of tissues derived from all three embryonic layers. NF-1 vasculopathy has been described primarily in peripheral arteries, but arteries supplying the CNS may also be involved. Of those, extracranial vertebral involvement is the commonest and most important. A series of four patients with NF-1 and vascular disease of the vertebral artery is described with a review of the pathophysiology, vascular phenotypes, their management and the pertinent literature.

[Transarterial embolisation of intracranial dural arteriovenous malformations with ethylene vinyl alcohol copolymer (Onyx18)]

OBJECTIVE

To report our recent experience in transarterial embolisation of dural arteriovenous malformations (DAVM) using a new liquid embolic agent, Onyx18.

PATIENTS AND METHODS

6 patients were enrolled in this series. Clinical presentation was separated into 2 groups: aggressive (n=2), non aggressive (n=4). The DAVM was located at the superior sagittal sinus (n=1), at the transverse sinus (n=2), at the condylian canal (n=1), in the lesser sphenoid wing region (n=1), and in the tentorium region (n=1). The DAVM drained directly into a condylian or a cortical vein for three patients and into a venous sinus with cortical venous reflux for the three others. In this latter situation, the sinus was anatomically excluded from the normal brain venous drainage.

RESULTS

A full brain angiogram including both internal carotid arteries, both external carotid arteries and ipsilateral vertebral artery, was performed before and after each treatment. The feeder chosen after a selective catheterisation for Onyx18 injection was always meningeal. Each treatment consisted of a single Onyx injection after one unique feeder catheterisation. Complete anatomical exclusion of the DAVM was achieved and demonstrated by the post treatment angiogram in all cases. There was no clinical complication after the treatment.

CONCLUSION

Onyx18 used is a safe treatment for DAVMs. When its injection is performed in optimal conditions, it fills the total DAVM and its drainage vein or sinus after a single arterial feeder catheterisation.

ARM des vaisseaux cervico-encéphaliques : technique, principales applications cliniques

Magnetic resonance angiography (MRA) is a very valuable tool in the routine evaluation of patients with stroke syndrome. It provides powerful noninvasive imaging of the cervical and intracranial vessels allowing the detection and the diagnosis of vascular anomalies. MRA usefully supplements, during the same examination, the analysis by MRI of the cerebral parenchyma. We will describe the indications of the various techniques (MRA with and without injection of contrast media) and show the value, artifacts and limitations of MRA in atherosclerotic stenosis or occlusive disease and in arterial dissections. This noninvasive vascular assessment will depend on the initial therapeutic orientation. Within the framework of the hemorrhagic stroke, we will discuss the role and the interest of dynamic MR angiography in the tracking and control of intracranial aneurysms and also the contribution of this newer sequences with gadolinium injection in the detection of cerebral vascular malformations.

Ehlers-Danlos syndrome type IV and recurrent carotid-cavernous fistula: review of the literature, endovascular approach, technique and difficulties

We report the follow-up of a previously published case (Forlodou et al. Neuroradiology 38:595-597, 1996) of carotido-cavernous fistulas (CCFs) in a patient presenting with type IV Ehlers-Danlos syndrome (EDS 4) that were successfully treated twice by an endovascular approach. Initial treatment with a detachable balloon was in 1994 for a right CCF, and, 8 years later, a left CCF was treated by selective transarterial occlusion of the cavernous sinus with coils. Unfortunately, the patient suffered from a spontaneous post-operative intracranial haemorrhage in the left hemisphere and died. Review of the literature, technical considerations for bilateral CCF and complication are discussed.

Imagerie des accidents vasculaires cerebraux en urgence

Over the last 25 years, advances in neuroimaging have significantly changed the evaluation and management of acute stroke syndromes. In the seventies, computed tomography (CT) could differentiate between ischemic and hemorrhagic stroke. Magnetic resonance imaging (MRI) is nowadays the imaging modality of choice in the initial assessment of acute stroke. MRI images can better discriminate acute, subacute and chronic infarcts, differentiate venous from arterial infarcts, detect arterial dissection, stenosis or occlusion. Diffusion-weighted images are highly sensitive and specific to acute infarction and the combination with perfusion technique is suitable to define potentially reversible ischemia (area of cerebral "mismatch" which is thought to represent the so-called ischemic penumbra). This penumbra is a potential therapeutic target of valuable interest for the treating physician.