Subarachnoid hemorrhage from spontaneous dissection of the anterior cerebral artery.
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Adult↗
Biomedical subjects
X Leclerc
Publications and source records attributed to X Leclerc.
[Main temporal aspects of the MRI signal of subdural hematomas and practical contribution to dating head injury].
BACKGROUND AND PURPOSE: MRI signal of a subdural hematoma (SDH) is often regarded as similar to that of an intracerebral hematoma but no precise study has analyzed the evolution of the signal of subdural hematomas. Their dating is however significant, in particular in the child, within the context of the diagnosis of child abuse. The objective of this study is to compare with MRI a group of adult patients having a subdural and/or intracerebral, in order to study the evolution of the signals of these two types of hematomas. MATERIAL AND METHODS: This prospective study included patients hospitalized for post-traumatic acute subdural or intracerebral hematoma. The protocol included an emergency brain CT and 4 MRI at fixed times: in emergency (early phase), between the third and the seventh day (early subacute phase), during the third week (late subacute phase), and after four months after the hemorrhage. The protocol included T1-weighted sequences before and after injection of gadolinium, T2-weighted, fluid-attenuated inversion-recovery (FLAIR), gradient echo and diffusion. RESULTS: Eighteen patients were included and all 72 MRI were interpretable. The time course of the cerebral hematomas was similar to that described in the literature, whereas that of subdural hematomas was different in 15 patients. This distinction was significant in the early phase for subdural hematomas, which displayed hypersignal in T2 and FLAIR, whereas cerebral hematomas showed a hyposignal in the same sequences. The variation was also notable in the early subacute period during which subdural hematomas displayed hypersignal in T1, FLAIR and diffusion, and isosignal in T2, whereas cerebral hematomas showed isosignal in T1, and hyposignal in T2, FLAIR and diffusion. CONCLUSION: The time course of MRI signal of subdural hematomas is different from that of cerebral hematomas. This difference is significant in T2 sequence and FLAIR, especially in the early subacute period. These radiographic observations in adults can be useful for the MRI dating of subdural hematomas in shaken-baby syndrome.
Adult↗
The role of spiral CT for the assessment of the intracranial circulation in suspected brain-death.
BACKGROUND AND PURPOSE: The aim of this study was to assess the role of spiral CT for the diagnosis of brain death. METHODS: Over a 12-month period, 15 patients that fulfilled the clinical criteria of brain death were referred from the intensive care unit to evaluate remaining intracranial blood flow by spiral CT. The clinical diagnosis was confirmed by an apnea test in all cases. Two phases of spiral CT were performed at 20 and 60 seconds after the start of contrast media injection. Qualitative analysis included the evaluation of vessel opacification (arteries and veins) by two radiologists in consensus. RESULTS: The cortical segments of the middle cerebral artery (MCA) were assessable in all patients, whereas the internal cerebral veins could not be evaluated in five patients due to artifacts or intracranial hemorrhage. Opacification of the major branches of the circle of Willis was observed in seven cases. Unilateral opacification of cortical branches of the MCA occurred in one. We did not observe bilateral enhancement of cortical MCA branches. The internal cerebral veins did not enhance in brain death. CONCLUSION: The absence of internal cerebral vein opacification and the absence of bilateral enhancement of cortical MCA branches constituted the best criteria of brain death by contrast enhanced spiral CT.
Adolescent↗
[Imaging of acute stroke].
Acute stroke patients represent an important diagnostic and therapeutic challenge. Patients with brain damage in the ischemic, but not yet infarcted, phase have the greatest potential for recovery. Here we review the most commonly employed diagnostic tools that are currently used before stroke therapy. While computed tomography is pertinent to differentiate ischemic from hemorrhagic stroke, this technique cannot be used as an etiological screening too. The ischemic origin of symptoms can be confirmed with magnetic resonance imaging which also contributes to for therapeutic decision making, prognosis assessment and etiological screening.
Acute Disease↗
Endovascular treatment of intracranial aneurysms with matrix detachable coils: immediate posttreatment results from a prospective multicenter registry.
BACKGROUND AND PURPOSE: Endovascular treatment of intracranial aneurysms by using detachable coils has become an accepted alternative to surgery. To reduce the rate of aneurysm recanalization after treatment, biologically active polyglycolic/polylactic acid-covered platinum coils have been proposed. A prospective and multicenter registry was conducted in France to evaluate the safety and short-term and long-term efficacy of Matrix detachable coils. This first analysis is focused on the safety and short-term efficacy. METHODS: Two hundred sixty-one patients having ruptured or unruptured aneurysms treated via endovascular approach were included in this registry. Patients with giant aneurysms or in poor clinical condition (Glasgow Coma Scale < 10) were excluded. Because of various protocol violations, clinical analysis was conducted in 236 patients having 244 aneurysms. Technical and clinical complications were systematically recorded. Angiographic analysis was performed by a core laboratory by using the Raymond Grading Scale on 224 patients having 232 aneurysms. RESULTS: Complete occlusion was achieved in 102 aneurysms (44.0%); neck remnant, in 58 aneurysms (25.0%); and aneurysm remnant, in 72 aneurysms (31.0%). Technical and clinical complications related to the procedure were encountered in 43 patients (18.2%). Postoperative modification of the clinical status was observed in 12 patients (5.1%). Two patients died (0.8%), 6 had a permanent deficit (2.5%), and 4 had a transient deficit (1.7%). Treatment-related mortality was 0.8% and permanent morbidity was 2.5%. CONCLUSION: Endovascular treatment of intracranial aneurysms by using Matrix detachable coils is feasible and demonstrated initial angiographic results and overall morbidity and mortality rates that are within the ranges found in the literature in the use of bare platinum coils.
Adolescent↗
[Angiographic resonance magnetic digital substration angiography (ARM-DSA) sequences in the study of cerebral arterio-venous malformations].
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Angiography, Digital Subtraction↗
[Neuroimaging characteristics of intracerebral haematoma].
The objective of brain imaging is to identify the hematoma according to its different stages and to find a potential underlying cause because of the risk of recurrence and the possibilities of treatment. In emergency, the diagnosis of hematoma is often obtained by CT scan, however today MRI has proved to be more accurate than CT to detect hemorrhage and to identify an underlying etiology. In some cases, according to the patient age, the medical history and the location of the hematoma, it may be necessary to perform a conventional angiography in order to exclude an intracranial vascular malformation. The aim of this review is to detail the different aspects of intracerebral hemorrhages according to the sequences and the temporal evolution, and to describe special findings which can help to identify an underlying etiology.
Cerebral Hemorrhage↗
[Neuroimaging characteristics of cerebral infarcts].
Over the last years, technical advances in neuroimaging have allowed drastic improvements in the assessment of acute ischemic cerebral events. Beyond conventional morphological analysis, diffusion-weighted and perfusion-weighted MRI now enable routine functional assessment of brain tissue; spectroscopy and diffusion tensor imaging still remains in the domain of clinical research. During acute ischemia events, diffusion-weighted MRI can detect the movements of water molecules and cytotoxic edema related to cell injury enabling rapid diagnosis and early assessment of cerebral ischemia. In conjunction with perfusion imaging, which detects hypoperfusion areas, diffusion-weighted MRI provides a means to identify areas of penumbra ischemia. More recent multislice computed tomographic (CT) scans with multimodal analysis are also very competitive for assessment of cerebral ischemia (non-enhanced CT, CT angiography and perfusion CT). The purpose of this paper is to describe the CT and MRI patterns during the different stages of cerebral infarcts.
Acute Disease↗
[Dynamic MRA in the evaluation of intracranial vascular diseases].
Conventional catheter angiography (CCA) remains the gold standard for the evaluation of most intracranial vascular malformations. MRA techniques such as Time of Flight, Phase Contrast or 3D contrast-enhanced MRA, provide anatomic evaluation but without hemodynamic information. Recently developed, dynamic MRA is based on dynamic acquisition of images and image subtraction; these two principal characteristics produce images comparable to those obtained by CCA. The purpose of this review is to explain the principles, advantages and drawbacks of this technique in the evaluation of arteriovenous malformations, arteriovenous fistulas, aneurysms and venous thrombosis.
Adult↗
[Diagnosis and follow-up of cervical arterial dissections--results of the SFNV-SFNR study].
INTRODUCTION: the objective of this study was to determine the role of radiological techniques in the diagnosis, assessment of severity and follow-up of cervical arterial dissections. MATERIAL AND METHODS: from 1995 to 2001 a multicentre retrospective study was conducted in 24 hospital centers. A multiple-choice questionnaire was sent to each center in order to collect clinical information and imaging details regarding the diagnosis and follow-up of cervical arterial dissections. RESULTS: information was gathered on 459 patients, comprising a total of 384 carotid artery dissections and 170 vertebral artery dissections. A mean of 4.85 diagnostic examinations per patient were conducted. Morphological imaging of the brain by CT or by MRI was performed on all except 3 patients. Cervical Doppler ultrasound examination was the most frequently performed test throughout the entire study period (performed in 87% of patients). Conventional arteriography was a routinely employed test in 1995 whereas by 2001 it comprised only 31.2% of requested examinations, having been progressively replaced by MRI and MRA scanning, which comprised 60% of all examinations performed by 2001. A combination of cervical Doppler ultrasonography, axial MRI and MRA of the neck vessels were performed in 39.6% of patients in 2001. Examination of the intracranial vessels was performed by transcranial Doppler ultrasound in 40% of cases and by MRA in 30% of cases. For the follow-up of arterial dissections, an average of 1.4 examinations was performed per patient. The majority of such follow-up examinations comprised Doppler ultrasound and/or MRA of the neck arteries. CONCLUSION: The imaging diagnosis and follow-up of cervical arterial dissections will increasingly rely on non-invasive imaging techniques.
Carotid Artery, Internal, Dissection↗
[Diffusion MR imaging of the central nervous system: clinical applications].
Diffusion-weighted MR imaging is a technique in which image contrast is determined by the motion of water molecules within tissues. This motion is characterized by the apparent diffusion coefficient (ADC). This technique is particularly useful for the early detection of cerebral infarction but many other diseases of the central nervous system are associated with a change in water diffusion and may be assessed by diffusion-weighted MR imaging. This is an easy and fast pulse sequence providing useful data for early diagnosis and prognosis as well as information about underlying pathophysiology. After an overview of the basic concepts of diffusion imaging and the knowledge required for image interpretation, we will assess the potential value of this technique for the diagnosis of the main diseases of the central nervous system.
Brain Diseases↗
[Value of MRI in the etiologic diagnosis of cerebral infarction].
The causes of ischaemic brain damage are numerous. Four main groups are described: atherosclerotic disease of the cervical and intracranial arteries represents 50% of the causes, small vessel disease with lacunar infarcts 25%, cardio-embolic disease 20% and non-atheromatous arterial disease and blood dyscrasias 10%. In 10% of cases, no etiology is identified. MRI has a dominating place in the etiologic assessment of cerebral infarction, by distinguishing the various types of infarction, detecting associated abnormalities like leukoencephalopathy and haemorrhage and by analyzing the lumen and wall of vessels.
Atherosclerosis↗
[The role of carotid and transcranial Doppler sonography in the management of ischemic stroke].
Carotid stenosis is a common cause of ischemic stroke. The management of patients with a carotid lesion is mainly based on the degree of stenosis. Ultrasonography is a reliable and accurate method of quantification of the stenosis. The sonographic quantification is based on both velocity and morphological criteria. B mode, color or power Doppler as well as spectral Doppler are used for this purpose. The actual velocity criteria for a 70% stenosis (NASCET definition) are as follows: maximal systolic velocity above 230 cm.s-1, telediastolic velocity above 100 cm.s-1, carotid ratio above 4. The morphological quantification of the stenosis relies on Doppler imaging and B-mode coupling. With ultrasound, the residual area can be measured using a short axis plane, and the diameter reduction using a longitudinal plane. The different parameters provide complementary information that must be in agreement with one another. There is a growing interest in plaque characterization. Undoubtedly plaque structure and surface appearance also play a role in the individual risk of stroke. Thus, B-mode plaque analysis must be an integral part of the ultrasonographic examination. Transcranial Doppler is a complementary investigation that can be used to evaluate the hemodynamic consequences of the stenosis and to look for intracranial lesions. Optimal sonographic examination currently allows comprehensive evaluation of a carotid lesion.
Aortic Dissection↗
Endovascular treatment of remnants of intracranial aneurysms following incomplete clipping.
We report clinical and angiographic findings in eight patients treated by the endovascular approach for an intracranial aneurysm remnant after incomplete surgical clipping. They were seven women and one man, mean age 38 years (range 14-50 years). In three, the remnant was responsible for a recurrent subarachnoid haemorrhage. All were treated by embolisation of the remnant using Guglielmi detachable coils. In two, a nondetachable balloon was inflated in front of the remnant during coil detachment because of a wide neck. Mean clinical and imaging follow-up was 19 months (range 12-24 months). Immediate angiography showed complete occlusion of the remnant and follow-up clinical examination showed good or excellent recovery in all patients. Imaging follow-up confirmed persistent occlusion of the remnant in all cases.
Adolescent↗
[A critical appraisal of diagnostic imaging techniques in asymptomatic carotid stenosis].
Asymptomatic stenosis of the internal carotid artery requires a non-invasive imaging work-up. The objectives include the quantification of the degree of stenosis, the analysis of the atherosclerotic plaque and the consequences of this stenosis on the brain tissue. Previous studies showed the reliability of MR angiography and spiral CT for the assessment of the arterial lumen. However, the consensus is based on the association of ultrasonography and MRA because of the non-invasive approach of these examinations that allow a complete evaluation of both the extracranial and the intracranial vessels. Recent advances in MRI will probably allow to simultaneously analyze the arterial wall in order to detect the plaques at risk and to optimize the therapeutic approach.
Carotid Stenosis↗
[Neurologic emergencies].
Neurological symptoms are a very frequent cause of consultation in emergency units and require consultation with neurologists and neuroradiologists. The most frequent diagnoses are stroke syndrome, seizure, headache, confusion, meningitis and meningo-encephalitis, and facial palsy. The morbidity and mortality of neurological emergencies are strongly related to prompt medical management of the patients which often requires neuroimaging studies. The most common neurological emergencies will be reviewed.
Coma↗
[Headaches in the emergency context].
Headaches constitute one of the most frequent reason of consultation. Their causes are extremely varied. The first step consists in the analysis of the characteristics of the pain and the associated signs in order to distinguish primary and secondary headaches. Primary headaches, including migraines and tension-type headaches are the most frequent types and do not require imaging evaluation. Secondary headaches are related to an organic cause and require specific investigations. In case of suspected symptomatic or secondary headaches, brain imaging plays an important role in the etiologic work-up. The main purpose of imaging in an emergency setting is to diagnose a life-threatening disease.
Acute Disease↗
[Management of patients after a first seizure].
Neuroimaging evaluation in patients after a first seizure could be easily determined on the basis of seizure history, neurological examination, blood sample analysis and electroencephalography. The main objectives of the initial work-up are to differentiate a true seizure event from seizure-like symptoms, to exclude a single seizure as a manifestation of non organic cause and finally to consider the seizure as a result of cerebral lesion or inaugurate epilepsy. When a new onset seizure is diagnosed, urgent neuroimaging is recommended only in patients with focal neurological deficit, persistent or worsening alteration in the level of consciousness and when clinical and biological data lead to a suspected vascular or infectious etiology. Brain CT scan is usually more available in emergency to identify the cause of seizure. It may have an important role for the therapeutic strategy and may defer MRI investigation. Nevertheless, brain MRI must be performed in emergency when CT scan is not conclusive despite a severe clinical condition or in case of cerebral venous thrombosis. Imaging modalities depend on clinical data, patient age and suspected epilepsy type.
Brain Diseases↗