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Biomedical subjects

Jean-Yves Gauvrit

Publications and source records attributed to Jean-Yves Gauvrit.

At least 19 recordsLinked to original sources
PubMed2006

Prognostic value of hyperintense vessel signals on fluid-attenuated inversion recovery sequences in acute cerebral ischemia.

BACKGROUND: Fluid-attenuated inversion recovery (FLAIR) sequences may reveal hyperintense vessel signals (HVS) at the acute stage of cerebral ischemia. The aim of this study was to test the hypothesis that HVS are associated with a worse outcome. METHODS: We included 30 consecutive patients admitted within 12 h after onset of hemispheric cerebral ischemia. The outcome was assessed with the modified Rankin Scale at month 1. RESULTS: Proximal HVS were present in 9 patients and distal HVS in 16. All patients with proximal occlusions on time-of-flight sequences had distal HVS on FLAIR. Patients with poor outcome at month 1 (modified Rankin Scale 3-6) more frequently had had HVS on MRI (12/13 vs. 4/17; p< 0.001). CONCLUSION: Distal HVS found on FLAIR sequences within 12 h of acute cerebral ischemia are associated with a worse 1-month outcome.

Adult↗
PubMed2006

Characterization and comparison of the chromatographic performance of different types of reversed-phase stationary phases.

The chromatographic performance of several base-deactivated stationary phases was evaluated with a specific chromatographic test. Seven basic test compounds, possessing different physico-chemical properties were injected on different supports with two mobile phases: one at pH 7.0 (acetonitrile-phosphate buffer, 40:60, v/v), and the other at pH 3.0 (acetonitrile-phosphate buffer, 15:85, v/v). Chromatographic parameters obtained under these conditions were treated by principal component analysis (PCA) to separate base deactivated supports according to their silanol activity (pH 7.0 mobile phase) and hydrophobic properties (pH 3.0 mobile phase). The information given by the specific test column evaluation was improved with complementary chemometric tools such as hierarchical cluster analysis. The same base deactivated supports were also tested following a general test procedure issued from the literature and obtained fundamental properties (in particular silanol activity and hydrophobicity) were compared with column evaluation obtained with the specific test: results were in good agreement, although the use of the specific test offered a better differentiation between numerous base-deactivated supports.

Chemical Phenomena↗
PubMed2006

Intracranial aneurysms treated with Guglielmi detachable coils: imaging follow-up with contrast-enhanced MR angiography.

BACKGROUND AND PURPOSE: To compare the utility of contrast-enhanced MR Angiography (CE-MRA) with digital subtraction angiography (DSA) after endovascular treatment of intracranial aneurysms with Guglielmi detachable coils. METHODS: From April 1999 to August 2002, 106 patients with 107 aneurysms treated by endovascular coiling using Guglielmi detachable coils underwent simultaneous DSA and CE-MRA at follow-up (mean: 12.9 range: 5 to 27 months). DSA was performed as the standard reference. MR angiographic images were analyzed independently by 2 senior radiologists (J.-Y.G., S.C.) and DSA by a third radiologist (X.L.). Findings were assigned to 1 of 3 categories: complete obliteration (class 1), residual neck (class 2) and residual aneurysm (class 3). RESULTS: DSA at follow-up demonstrated 65 (60.6%) complete obliterations (group 1), 21 (19.7%) residual necks (group 2) and 21 (19.7%) residual aneurysms (group 3). One patient (0.9%) experienced aneurysm rebleed during the follow-up period. Among 101 assessable imaging comparisons, interobserver agreement was determined to be very good for CE-MRA (kappa=0.96) with only 4 discrepancies between both examiners. Comparison between CE-MRA and DSA showed an excellent agreement between techniques (kappa=0.93). Of the 21 with residual necks described on DSA, 20 were seen on CE-MRA. CE-MRA detected all 19 residual aneurysms. CONCLUSIONS: CE-MRA after selective embolization of intracranial aneurysm is useful and comparable to DSA in the assessment of aneurysmal recanalization either as residual neck or aneurysmal sac.

Adolescent↗
PubMed2005

Fluid-attenuated inversion recovery (FLAIR) sequences for the assessment of acute stroke: inter observer and inter technique reproducibility.

BACKGROUND AND PURPOSE: Diffusion-weighted magnetic resonance (MR) imaging (DWI), and three-dimensional (3D) time-of-flight (TOF) MR angiography (MRA), are highly sensitive for the early detection of stroke and arterial occlusion. However, only a few studies have evaluated the sensitivity of conventional MR sequences that are usually included in the imaging protocol. The aim of this study was to evaluate interobserver and intertechnique reproducibility of Fluid-Attenuated Inversion Recovery (FLAIR) sequences for the diagnosis of early brain ischemia and arterial occlusion. METHODS: Over a 30-month period, brain MR examinations were performed in 34 patients within 12 hours after stroke onset. Imaging protocol included FLAIR sequences, DWI and 3D TOF MRA. Ten observers including radiologists and neurologists, performed separately a visual interpretation of FLAIR images for the detection of brain ischemia and arterial occlusion seen as an arterial high signal. DWI and 3D TOF MRA were used as reference and interpreted independently by two senior radiologists. Interobserver agreement was assessed for image quality, detectability and conspicuity of lesions whereas intertechnique agreement was only judged for lesion detectability. RESULTS: On FLAIR sequences, interobserver agreement for the detection of brain ischemia and arterial occlusion was excellent (kappa = 0.81 and 0.87 respectively). The concordance between FLAIR and DWI sequences for the detection of brain ischemia and between FLAIR and 3D TOF MRA for the detection of arterial occlusion were judged as excellent for all observers (kappa = 0.91 and 0.89 respectively). CONCLUSION: Although DWI is the most sensitive technique with which to detect acute stroke, FLAIR imaging may also be useful to demonstrate both acute ischemia and arterial occlusion with an excellent interobserver reproducibility.

Adult↗
PubMed2005

Three-dimensional dynamic magnetic resonance angiography for the evaluation of radiosurgically treated cerebral arteriovenous malformations.

We assessed the value of three-dimensional (3D) dynamic magnetic resonance angiography (MRA) for the follow-up of patients with radiosurgically treated cerebral arteriovenous malformations (AVMs). Fifty-four patients with cerebral AVMs treated by radiosurgery (RS) were monitored using conventional catheter angiography (CCA) and 3D dynamic MRA with sensitivity encoding based on the parallel imaging. Cerebral AVM was qualitatively classified by two radiologists into one of five categories in terms of residual nidus size and persistence of early draining vein (I, >6 cm; II, 3-6 cm; III, <3 cm; IV, isolated early draining vein; V, complete obliteration). 3D MRA findings showed a good agreement with CCA in 40 cases (kappa=0.62). Of 23 nidus detected on CCA, 3D dynamic MRA showed 14 residual nidus. Of 28 occluded nidus on 3D dynamic MRA, 22 nidus were occluded on CCA. The sensitivity and specificity of 3D dynamic MRA for the detection of residual AVM were 81% and 100%. 3D dynamic MRA after RS may therefore be useful in association with MRI and can be repeated as long as opacification of the nidus or early venous drainage persists, one CCA remaining indispensable to affirm the complete occlusion at the end of follow-up.

Adult↗
PubMed2005

A study of interlaboratory influence on column evaluation.

A liquid chromatography method for the characterization of base deactivated columns was investigated in a collaborative study involving six laboratories. This work was carried out on two chromatographic supports (Xterra RP 18 and Symmetry Shield). Different cooling systems, namely water bath and air oven, were tested and it was shown that column thermoregulation did not significantly influence chromatographic data. In order to control the mobile phase composition, the latter was prepared by weight rather than volume. Thanks to the injection of a set of selected neutral compounds, extra-column effects were evaluated in each of the participating laboratories. The results showed that chromatographic supports tested in different laboratories and following the same test protocol could be effectively compared.

Chromatography, High Pressure Liquid↗
PubMed2005

3D rotational angiography: use of propeller rotation for the evaluation of intracranial aneurysms.

We compared two methods of 3D digital subtraction angiography (DSA)--propeller and standard rotation--for the assessment of aneurysmal morphology and its relation to neighboring vessels. Aneurysms were correctly visualized and localized with both techniques. 3D DSA with propeller rotation technique seems to be effective and allows us to reduce the amount of contrast material related to a shortened acquisition time. Technical progress including propeller rotation allows a larger range of rotation and faster rotational speeds.

Adolescent↗
PubMed2005

Intracranial aneurysms treated with Guglielmi detachable coils: usefulness of 6-month imaging follow-up with contrast-enhanced MR angiography.

BACKGROUND AND PURPOSE: This study was undertaken to assess the utility of contrast-enhanced MR angiography at 6 months after endovascular treatment of intracranial aneurysms with Guglielmi detachable coils. METHODS: Contrast-enhanced MR angiography was performed in 47 patients at 6 and 12 months after endovascular treatment of intracranial aneurysms (48 aneurysms). Digital subtraction angiography (DSA) was used as reference and was performed at 12 months after the treatment in all patients. MR angiographs were analyzed independently by two senior radiologists. DSA and MR angiography findings were assigned into one of three categories: complete obliteration, residual neck, or residual aneurysm. RESULTS: All examinations were assessable. Interobserver agreement was judged as very good for contrast-enhanced MR angiography (kappa=0.96), with one discrepancy between examiners. Comparison between MR angiography at 6 months and DSA at 12 months showed an excellent agreement between techniques (kappa=0.93). Two cases of complete occlusion at DSA were misclassified as a residual neck at 6-month MR angiography. All aneurysm recanalizations at DSA already were detected on MR angiography at 6 months. The size of aneurysm recanalization did not increase between both MR angiographs performed at 6 and 12 months. CONCLUSION: Contrast-enhanced MR angiography after selective embolization of intracranial aneurysm seems to predict properly early aneurysm recanalizations.

Adult↗
PubMed2005

Subarachnoid hemorrhage as the initial presentation of dural sinus thrombosis.

Cerebral venous thrombosis (CVT) can be difficult to diagnose because of its wide spectrum of clinical manifestations. Its diagnosis may be further complicated when patients initially present with acute subarachnoid hemorrhage (SAH). We report on four patients with SAH revealing a CVT and discuss the role of imaging for diagnostic and pretherapeutic workup. In three women and one man presenting with severe headaches, images initially suggested SAH with no associated parenchymal bleeding. In all patients, SAH involved the sulci of the convexity and spared the basal cisterns. Digital subtracted angiography showed occlusion of intracranial venous sinuses but did not reveal any other cause of SAH. All patients improved with anticoagulant therapy. Risk factors for CVT and SAH, namely, head trauma and oral contraception, were identified in two patients. These cases highlight the fact SAH may reveal a CVT, which should be considered in the diagnostic workup of SAH, especially when the basal cisterns are not involved.

Adult↗
PubMed2004

Partially reversible quadruple sectoranopia caused by vascular steal due to an arteriovenous malformation.

BACKGROUND: Lateral, homonymous upper and lower field blind sectors sparing a horizontal zone define quadruple sectoranopia. This rare campimetric deficit involves ischemia or infarction of parts of the lateral geniculate body supplied by the distal anterior choroidal artery. METHODS: A 41-year-old patient presented with a complaint of blurred vision. Visual acuity was 20/20 on both sides. Visual field showed a left quadruple sectoranopia. CT scan, MRI, MRA and conventional angiography showed a right cerebral arteriovenous malformation supplied partly by the right anterior choroidal artery. Partial retinal nerve fiber layer atrophy matched to the campimetric deficit proved that some degree of infarction involved the lateral geniculate body. RESULTS: The arteriovenous malformation was treated with stereotactic radiosurgery. Two years after treatment, the nidus had completely disappeared. The campimetric deficit began improving from 19 months onwards after stereotactic radiosurgery. Twenty-eight months after treatment, the superior defect had completely reversed. CONCLUSIONS: Quadruple sectoranopia involves ischemia or infarction of parts of the lateral geniculate body supplied by the distal anterior choroidal artery. Following radio-induced angioma thrombosis, blood was no longer shunted away from the right lateral geniculate body, whose viable areas resumed their activity. Accordingly, a partial campimetric recovery occurred.

Adult↗
PubMed2004

Concordance rate differences of 3 noninvasive imaging techniques to measure carotid stenosis in clinical routine practice: results of the CARMEDAS multicenter study.

BACKGROUND AND PURPOSE: To replace digital subtraction angiography (DSA) in carotid stenosis evaluation, noninvasive imaging techniques have to reach a high concordance rate. Our purpose is to compare the concordance rates of contrast-enhanced MR angiography (CEMRA) and CT angiography (CTA) with Doppler ultrasound (DUS) in clinical routine practice. METHODS: We evaluated prospectively with DUS, CEMRA, and CTA 150 patients suspected of carotid stenosis. The overall concordance rates of the 3 techniques were calculated for symptomatic stenosis > or =50% and > or =70%, for asymptomatic stenosis > or =60%, and for occlusion. For the carotid arteries treated by surgery (n=97), the results of each method and combined techniques were recorded, and misclassification rates were evaluated from surgical reports. RESULTS: The overall concordance rates of DUS-CEMRA, DUS-CTA, and CEMRA-CTA were not statistically different. However, the concordance rate of DUS-CEMRA (92.53%) was significantly higher than that for DUS-CTA (79.10%) in the surgical asymptomatic stenosis group (P=0.0258). CTA considered alone would misclassify the stenosis in a significant number of cases (11 of 64) in the surgical asymptomatic group compared with CEMRA (3 of 67) and DUS (1 of 66) (P=0.0186 versus MRA, P=0.0020 versus DUS). CONCLUSIONS: With the techniques as utilized in our study, the overall concordance rates of combined noninvasive methods are similar for measuring carotid stenosis in clinical routine practice, but in asymptomatic carotid stenosis, the decision making for surgery is significantly altered if DUS and CTA are considered in place of DUS and CEMRA.

Aged↗
PubMed2004

Diffusion/perfusion-weighted magnetic resonance imaging after carotid angioplasty and stenting.

BACKGROUND AND PURPOSE: Carotid angioplasty and stenting, a so far non-validated procedure, may be an alternative to surgery in patients with a high surgical risk. However, it carries also a risk of cerebral embolic events. The purpose of this study was to evaluate tissue signal abnormalities in the brain before and after carotid angioplasty and stenting by means of diffusion- (DWI) and perfusion (PWI) weighted magnetic resonance imaging (MRI). METHODS: We performed cerebral MRI before and after carotid angioplasty in 22 consecutive patients, with 23 treated high-grade carotid stenoses. The lesions were located at the origin of the internal carotid artery (ICA) in 20 patients, and at the origin of the common carotid artery (CCA) in 2. MRI was performed the day before, and repeated within 24 hours after the procedure, and examined by two neuroradiologists. RESULTS: All stent implantations were successful but 4 patients developed an acute neurological deficit within 24 hours after carotid angioplasty. On PWI, Time To Peak (TTP) values ipsilateral to the carotid stenosis were increased before the procedure in 15 patients, and had remained normal in 6 and were not assessable in 1. After the procedure, TTP values were normal in 12 patients, increased in 8 and not assessable in 2. On DWI, new ipsilateral lesions were detected in 2 patients: 1 with an acute neurological deficit and 1 symptom free. CONCLUSION: Perfusion deficits may be present in severe carotid stenosis and be improved within 24 hours by carotid angioplasty and stenting. Asymptomatic infarcts may occur.

Aged↗
PubMed2004

Giant vertebrobasilar aneurysms: endovascular treatment and long-term follow-up.

OBJECTIVE: To report long-term imaging follow-up and clinical outcome of 13 patients with a giant vertebrobasilar aneurysm treated by parent artery occlusion (PAO). METHODS: From 1994 to 2000, 13 consecutive patients with a giant vertebrobasilar aneurysm were treated by PAO. Symptoms were related to mass effect in nine patients and to a subarachnoid hemorrhage in four. Endovascular treatment consisted of aneurysm trapping in nine patients and occlusion of one or both vertebral arteries in four. We assessed the clinical outcome and imaging findings in all patients during a 28-month period. RESULTS: Endovascular treatment resulted in clinical improvements in eight patients, worsening of symptoms in four, and death in one. One woman with a ruptured vertebral aneurysm died from a rebleeding after PAO without trapping. One man developed a brainstem infarction after lower basilar artery occlusion and incurred hemiparesis. In three patients, symptoms of mass effect increased after the procedure. Long-term follow-up revealed good or excellent clinical outcome in all patients and a sharp decrease in size of the thrombosed aneurysm in nine patients. One basilar aneurysm recanalized despite selective coiling and subsequent bilateral vertebral artery occlusion; one vertebral aneurysm and one basilar aneurysm did not decrease in size despite complete occlusion. CONCLUSION: Giant vertebrobasilar aneurysms are rare and challenging lesions for both neurosurgeons and neurointerventionalists. Their treatment by endovascular PAO remains safe and effective. Early clinical worsening may be observed, but long-term follow-up shows good or excellent results in most patients. This treatment can be carried out with minimal morbidity and mortality using clinical and angiographic monitoring.

Adolescent↗
PubMed2004

Endovascular treatment of ruptured intracranial aneurysms in elderly people.

BACKGROUND AND PURPOSE: Endovascular detachable coil is being increasingly used for the treatment of cerebral aneurysms but little information is available about its feasibility and effectiveness in people. We assessed clinical outcomes in elderly patients with ruptured intracranial aneurysms treated with selective embolization. METHODS: Between 1996 and 2002, 68 patients aged 65-80 years (mean age, 71 years) were treated by selective embolization with coils. Among them, 34 had a Hunt and Hess (HH) grade of I or II; 15, an HH grade of III; and 19, an HH grade of IV or V. All patients except four were treated within 72 hours after initial bleeding; those four patients had an HH grade of IV or V and were treated at 3-6 weeks after their clinical recovery. Clinical outcomes were assessed by using the Modified Glasgow Outcome Scale. Mean duration of follow-up was 20 months (range, 6-36 months). RESULTS: Endovascular treatment resulted in 47 complete occlusions (69%), 15 neck remnants (22%), and six incomplete occlusions (9%). Procedural complications occurred in eight patients (12%). Outcomes were good or excellent in 40 patients (59%), including the four treated 3-6 weeks after initial bleeding. A fair or poor outcome was observed in 14 patients (20.5%), including two with an HH grade of I or II. Of 14 patients (20.5%) who died, 13 (93%) had an HH grade of IV or V. No rebleeding occurred during follow-up. CONCLUSION: Endosaccular coiling may be proposed in elderly people with ruptured intracranial aneurysms. However, in patients with HH grade IV or V lesions, morbidity and mortality rates remain high, and embolization should be considered only after their clinical recovery.

Aged↗
PubMed2004

Selective endovascular treatment of intracranial aneurysms with sapphire coils.

BACKGROUND AND PURPOSE: Endovascular treatment with detachable coils is an accepted alternative to surgical clip placement for intracranial aneurysms. The purpose of this study was to evaluate the safety and reliability of the Sapphire coil, a new platinum coil for the treatment of intracranial aneurysms. METHODS: Between August and September 2003, 20 consecutive patients (13 women, seven men; mean age, 49 years; range, 33-77 years) with 20 intracranial aneurysms were referred to our department for endovascular treatment. Fifteen patients presented with subarachnoid hemorrhage, whereas five had asymptomatic, unruptured aneurysms. All patients were treated by selective endosaccular coil placement with the new coils. The remodeling technique was used in five wide-neck aneurysms. Clinical outcomes were assessed with the modified Glasgow Outcome Scale. RESULTS: Aneurysmal occlusion with the new coils alone was successful in 16 patients and resulted in 12 complete occlusions and four neck remnants. Because of the limited Sapphire product line, additional Guglielmi detachable coils (GDCs) were required in four patients, two of whom received one 3D GDC of 3 mm diameter and two of whom received Ultra-Soft GDCs. Technical complication (stretching of a coil) occurred in one patient. Clinical outcomes were excellent in 14 patients and good in two. CONCLUSION: Although the study was limited by its small patient population, the results show that selective endovascular treatment of intracranial aneurysms with Sapphire coils was not associated with an unexpected incidence of adverse events. Excellent anatomic and clinical results that were obtained in most patients suggest that Sapphire coils may have value in the treatment of intracranial aneurysms.

Adult↗
PubMed2004

HyperForm remodeling-balloon for endovascular treatment of wide-neck intracranial aneurysms.

A new, very compliant remodeling balloon microcatheter has been developed for the treatment of difficult wide-neck intracranial aneurysms (eg, arterial bifurcation or small artery aneurysms). We report selective embolization by the use of the remodeling technique with the HyperForm balloon in 16 consecutive patients with a wide-neck intracranial aneurysm located on an arterial bifurcation or a small artery or both.

Adult↗