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Biomedical subjects

J P Pruvo

Publications and source records attributed to J P Pruvo.

At least 19 recordsLinked to original sources
PubMed2006

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↗
PubMed2006

[MRI localization of paraclinoid carotid aneurysms].

AIM: The distal dural ring plane (DDRP) separates the intracavernous from the supracavernous paraclinoid internal carotid artery. The purpose of this MRI protocol is to evaluate the position of this plane for the characterization of paraclinoid aneurysms. METHOD: The protocol uses a T2 weighted sequence in two orthogonal planes (diaphragmatic and carotid planes) and two correlation lines in each plane. These lines pass through anatomo-radiological reference points correlated with the medio-lateral and antero-posterior margins of the DDRP. We use the intersection angle of these lines as the inferior radiological limit of the DDRP curve. RESULTS: An aneurysm located above this angle is supracavernous; an aneurysm located below this angle is intracavernous; an aneurysm crossing this angle is transitional. CONCLUSION: In difficult cases, this MRI protocol could help better characterize the exact localization of paraclinoid aneurysms on both sides of the cavernous sinus roof.

Carotid Artery Diseases↗
PubMed2006

[Midline tumors of the central nervous system].

The anatomy of the supratentoriel midline structures of the brain is complex: corpus callosum, third ventricle, trigone, choroid plexus, pineal gland, falx cerebri. Different types of tumors can arise from these structures including tumors of the trigone and septum, tumors of the falx, third ventricular tumors and pinal region tumors. These tumors share similar features: minimal clinical symptoms despite their occasional large size, mild non-specific intracranial hypertension syndrome, value of MRI for depiction of tumor location, stereotactic biopsy, relative difficulty of surgical management.

Adult↗
PubMed2006

[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↗
PubMed2005

Clinical outcome in patients with high-grade internal carotid artery stenosis after irradiation.

The authors followed up 41 consecutive patients (21 symptomatic) with internal carotid artery stenosis > or =70% and previous neck irradiation. After 28 months, 15 patients (36.6%) had died, five (12.2%) had had an ischemic stroke, and 15 (36.6%) had a new malignancy. Having a new malignancy was the only independent predictor of death. The major risk for patients with ICA stenosis > or =70% and previous neck irradiation is malignancy, not stroke.

Adult↗
PubMed2005

[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↗
PubMed2005

[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↗
PubMed2005

[MR imaging in mental retardation].

Mental retardation is considered idiopathic or not otherwise specified when no etiological diagnosis can be identified in spite of comprehensive history, physical examination and metabolic or genetic investigations. In such cases, brain MRI is indicated for patients with abnormal head size or shape, craniofacial malformation, somatic anomalies, neurocutaneous findings, seizures, focal neurological findings or behavioral and/or developmental problems. Brain anomalies are now considered a main category for the etiology of mental retardation. MRI evaluation should include axial images of the entire brain, sagittal images through the midline structures, and coronal images of the posterior fossa or entire brain. MRI allows detection of major and or minor cerebral anomalies or malformations, sometimes multiple. In the literature, the most frequently involved structures include: 1/ corpus callosum (hypoplasia, short corpus callosum and verticalized splenium), 2/ septum pellucidum (cavum septum pellucidum or cavum vergae), 3/ ventricles (ventriculomegaly), 4/ cerebral cortex (cortical dysplasia), 5/ cerebellum (hypoplasia), and 6/ extra-axial CSF spaces (enlargement). In our patient population, dysplasia involving the cerebellum and vermis have been identified, a finding that has not yet been described in the literature. MRI allows detection of multiple minor morphological anomalies. Most have classically been considered as normal variants but they may in fact be markers of cerebral dysgenesis and are currently the only anomaly detected in the work-up of patients with mental retardation. Their role in the pathogenesis of mental retardation is under evaluation.

Adolescent↗
PubMed2005

[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↗
PubMed2005

[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↗
PubMed2005

Brain MRI in late-onset multiple sclerosis.

Multiple sclerosis (MS) with clinical onset after 50 years of age is unusual (between 1 and 6%) and is frequently misdiagnosed. Furthermore, brain magnetic resonance imaging (MRI) abnormalities are frequently observed in subjects over 50 years of age. The aim of this study was to describe brain MRI in late-onset MS to evaluate the sensitivity and specificity of radiological MS criteria in patients aged over 50 years. We evaluated the brain MRI of 20 patients with onset of MS after 50 years of age. We compared these MRI with 26 controls matched for age, sex and vascular risk factors. MRI were blindly analysed by two neuroradiologists according to Paty et al.'s [Neurology38 (1988) 180] criteria, Fazekas et al.'s [Neurology38 (1988) 1822] criteria and Barkhof et al.'s [Brain120 (1997) 2059] criteria. The mean age at MRI scanning was 58 years. Sensitivity was 90% for Paty et al.'s criteria, 80% for Fazekas et al.'s criteria and 85% for Barkhof et al.'s criteria. Specificity was 54% for Paty et al.'s criteria, 69% for Fazekas et al.'s criteria and 65% for Barkhof et al.'s criteria. Barkhof et al.'s criteria are less specific in older patients than in young patients. We suggest that spinal cord MRI and cerebrospinal fluid analysis should be systematically performed in suspected late-onset MS in order to increase the specificity of the diagnosis.

Aged↗
PubMed2004

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↗
PubMed2004

[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↗
PubMed2004

[Spinal cord ischemia].

Traditional data and recent advances in the field of spinal cord ischemia are reviewed, with special attention to clinical and radiological features, as well as underlying etiology, outcome, and pathophysiology. Acute spinal cord ischemia includes arterial and venous infarction and global ischemia resulting from cardiac arrest or severe hypotension. MRI has become the technique of choice for the imaging diagnosis of spinal cord infarction. Correlation of clinical and MRI data has allowed diagnosis of clinical syndromes due to small infarcts in the central or peripheral arterial territory of the spinal cord. Diffusion-weighted MR imaging may increase the sensitivity and specificity for diagnosis of acute spinal cord infarction. Diagnosis of venous spinal cord infarction remains difficult. As for global ischemia, neuropathological studies demonstrated a great sensitivity of spinal cord to ischemia, with selective vulnerability of lumbosacral neurons. Chronic spinal cord ischemia results in a syndrome of progressive myelopathy. The cause is usually an arteriovenous malformation. Most often, diagnosis may be suspected on MRI, leading to diagnostic, and eventually therapeutic, spinal angiography.

Arteries↗
PubMed2004

[Cerebral arteriovenous malformations: value of the non invasive vascular imaging techniques].

Imaging evaluation of cerebral arteriovenous malformations (AVM) requires selective visualization of the different compartments of the malformation in order to select the therapeutic management. Conventional angiography remains the reference to analyze intracranial vessel conspicuity but non-invasive methods constitute an excellent alternative. Among these techniques, CT angiography is rarely used because of the need to inject iodinated contrast material and because of irradiation. MR angiography provides useful information and can be performed using several techniques: time of flight with or without contrast material injection, phase contrast, three-dimensional (3D) gradient echo acquisition after contrast material injection and, more recently, MR digital subtraction angiography. The purpose of this review article is to summarize the different non-invasive techniques for vascular imaging and to analyze the usefulness of these techniques for the assessment of brain AVMs.

Angiography, Digital Subtraction↗
PubMed2004

Supratentorial functional disturbances in two children with cerebellar cortical dysplasia.

When evaluating children with mental retardation, subtle cerebral and cerebellar morphologic anomalies are often noted at Magnetic Resonance Imaging (MRI). Some, such as cerebellar cortical dysplasia (CCD), have been considered as subtle markers of cerebral dysgenesis. Their functional significance and their effect on brain function, remain unknown. To study supratentorial functional disturbances related to CCD we performed Positron-Emission-Tomography (PET) studies in two children with isolated CCD, in order to investigate the degree of involvement of supratentorial structures. One had developmental delay, motor disturbances and ataxia, and the other one only had mental retardation. PET studies revealed hypoperfusion and hypometabolism within the vermis, thalamus and the right striatum in one case, and hypometabolism in the basal ganglia and cerebellar deep grey nuclei in the other case. Our results could lead to a hypothesis explaining motor disturbances as well as cognitive impairment, and could suggest a pathological functional significance of CCD. Nevertheless, the relationship between these findings and mental retardation needs further investigation.

Blood Glucose↗