Xavier Leclerc

Prevalence and significance of hyperdense middle cerebral artery in acute stroke.

Background and Purpose Early noncontrast computed tomographic scans may visualize a hyperdense middle cerebral artery before the infarct becomes visible. This sign disappears within a few days, corresponds to the clot itself, and might be associated with a poor prognosis. The aim of the study was to determine its prevalence, diagnostic value, relationship to demographic data, ability to separate embolic from nonembolic causes, short-term prognostic value, evolution over time, and relationship to arterial occlusion on angiography. Methods We performed this study using computed tomographic scans performed within 12 hours after onset in 272 consecutive unselected patients with a first acute cerebrovascular event. Results Seventy-three subjects had the hyperdense middle cerebral artery sign, leading to a prevalence of 26.8%in the whole group and 41.2% in patients with a middle cerebral artery infarct. Specificity was 100%, but sensitivity was only 30%. This sign was not dependent on cerebrovascular risk factors, but was more likely to occur in cortical and in large, deep, middle cerebral artery infarcts (p < 0.01). It provided only a 3.5% gain in predicting death, and one fifth of patients with the sign recovered within 2 weeks; this sign was not an independent variable of poor outcome on multiple linear regression. It spontaneously disappeared within a few days and was always related to an occlusion of the middle cerebral artery in patients who underwent early angiography. Conclusions The hyperdense middle cerebral artery sign is useful in the diagnosis of middle cerebral artery occlusion but does not always predict a poor prognosis.

Helical CT for the Diagnosis of Extracranial Internal Carotid Artery Dissection

BACKGROUND AND PURPOSE We attempted to evaluate the sensitivity of helical CT for the diagnosis of extracranial internal carotid artery (ICA) dissection. METHODS Sixteen consecutive patients with 18 angiographically confirmed extracranial ICA dissections were studied with a helical CT protocol with large-volume acquisition and thin axial slice reconstructions. A control group including normal and atherosclerotic ICAs was formed for comparison, and a blind interpretation of CT images was made by two observers. We evaluated the presence of stenosis, eccentric lumen, mural thickening, aneurysm, occlusion, and annular contrast enhancement. When the artery seemed to be occluded, we measured the external diameter of the ICA (1) on the occluded side, at its upper portion and most enlarged level, (2) at its lower portion, beyond the bulb, and (3) on the contralateral side, at is upper portion. RESULTS Interobserver agreement was good except for the presence of annular contrast enhancement. In the stenotic dissection group (n=12), the presence of a narrowed eccentric lumen at the upper portion of the ICA on axial CT images was classified correctly in all cases (sensitivity, 100%; specificity, 100%). An arterial wall thickening was seen in all cases of dissection but also in three cases of the control group. In the occlusive dissection group (n=6), the enlargement of the dissected artery was the best criterion (sensitivity, 100%, specificity, 100%) for occlusive dissection. CONCLUSIONS Helical CT seems to be a reliable method for evaluating extracranial ICA dissection. The analysis of the residual arterial lumen and the measurement of the external diameter of the carotid artery were the best criteria for the diagnosis. Further studies with larger groups are required to determine whether ICA dissections might be diagnosed using helical CT as a first procedure.

Cerebral venous thrombosis 3-year clinical outcome in 55 consecutive patients.

Abstract. An early diagnosis and heparin therapy have contributed to a decreased mortality in cerebral venous thrombosis (CVT). However, predictors of outcome are difficult to identify, because most studies suffered heterogeneity in diagnostic findings and treatments, retrospective design, and recruitment bias. The aim of this study was to evaluate the clinical outcome in 55 consecutive patients with CVT admitted over a 4-year period. The study population consisted of 42 women and 13 men, with a median age of 39 years (range 16–68). The diagnosis was performed with MRI in 53 patients, and angiography in 2. The outcome was assessed with the modified Rankin scale (mRs). After a median follow-up of 36 months (range: 12–60), 45 patients were independent (mRS 0–2), and 10 were dependent or dead (mRS 3–6). Of 48 survivors, 7 had seizures, 6 motor deficits, 5 visual field defects, 29 headache (migraine in 14, tension headache in 13, other in 2). The logistic regression analysis found focal deficits and cancer at time of diagnosis, as independent predictors of dependence or death at year 3, and isolated intra-cranial hypertension as an independent predictor of survival and independence. Mortality rates are low in the absence of cancer and focal deficits, and more than 80 % of survivors are independent after 3 years. However, 3/4 of survivors have residual symptoms. Therefore, despite a low mortality rate, CVT remains a serious disorder.

Computed Tomographic Angiography for the Evaluation of Carotid Artery Stenosis

BACKGROUND AND PURPOSE No previous study has compared the reliability of carotid artery measurement provided by axial images, shaded surface display (SSD), and maximum intensity projection (MIP). METHODS Helical CT and conventional angiography were performed prospectively in 20 patients with atherosclerotic stenosis of the internal carotid artery. Stenosis measurement was performed in a blinded fashion on angiography and CT by two independent examiners. Calcifications were segmented when they were located far enough from the vascular lumen. SSD and MIP were systematically performed for each carotid bifurcation. We measured stenosis using conventional angiography as standard and the different CT reconstructions (axial images, SSD, and MIP) by comparing the stenosis diameter at its narrowest point to the normal internal carotid artery. The degree of stenosis was classified into six groups: no stenosis, mild stenosis (< 30%), moderate stenosis (30% to 70%), severe stenosis (> 70%), near occlusion, and occlusion (100%). No measurement was made in cases of normal artery, near occlusion, and occlusion. RESULTS Correlations between angiography and the three types of reconstruction were very good. Axial sections correctly classified the carotid arteries in 95% of cases. In 10 carotid arteries, stenosis was not assessable by SSD and MIP because of calcifications. In the remaining carotid arteries, MIP correctly classified the degree of stenosis in 96% of cases, whereas SSD misclassified 21% of cases. CONCLUSIONS Our study showed that axial images provide a reliable evaluation of carotid artery stenosis. Calcifications are limiting factors in SSD or MIP. When atherosclerotic plaques are not calcified, MIP reconstructions provide a more reliable measurement of the vascular lumen than SSD.

Endovascular Treatment of Unruptured Intracranial Aneurysms: Comparison of Safety of Remodeling Technique and Standard Treatment with Coils

PURPOSE To analyze the safety of the remodeling technique compared with the safety of the standard treatment with coils for endovascular treatment of unruptured intracranial aneurysms in a large multicenter series of patients as part of the Analysis of Treatment by Endovascular Approach of Nonruptured Aneurysms (ATENA) study. MATERIALS AND METHODS The medical ethics committee approved the ATENA study, and all patients gave informed consent for participation in the study. The ATENA study was performed in 27 institutions. For each patient group, we recorded aneurysm characteristics, rate of adverse events related to the treatment, and patient outcome. RESULTS In this study, 547 patients (383 women, 164 men; mean age, 51.0 years +/- 11.1 [standard deviation]; range, 22-83 years) with 572 aneurysms were included; 325 patients were treated with coils alone and 222 patients were treated with the remodeling technique. The overall rate of adverse events related to the treatment-regardless of whether the adverse events led to clinical consequences-was 10.8% (35 of 325) for treatment with coils alone and 11.7% (26 of 222) for the remodeling technique. Thromboembolic events, intraoperative rupture, and device-related problems were encountered in 20 (6.2%), seven (2.2%), and eight (2.5%) of 325 patients in the standard treatment group and in 12 (5.4%), seven (3.2%), and seven (3.2%) of 222 patients in the remodeling technique group, respectively. The morbidity and mortality rates did not differ significantly between groups: 2.2% (seven of 325) and 0.9% (three of 325) in the standard treatment group and 2.3% (five of 222) and 1.4% (three of 222) in the remodeling technique group, respectively. CONCLUSION The remodeling technique was associated with a similar rate of adverse events and morbidity and mortality combined compared with the standard treatment with coils, and, thus, the remodeling technique is as safe as the standard treatment with coils.

Retractable Self-expandable Stent for Endovascular Treatment of Wide-necked Intracranial Aneurysms: Preliminary Experience

OBJECTIVE: Intracranial stenting combined with endosaccular coiling is a therapeutic alternative for the endovascular treatment (EVT) of wide-necked intracranial aneurysms. The current limitation of available stents is the impossibility to reposition them once they are partially deployed. Recently, the first retractable self-expandable stent has been developed and we sought to evaluate the use of this stent for EVT of wide-necked intracranial aneurysms. METHODS: Between March 2004 and March 2005, 11 patients with an unruptured aneurysm have been selected for this study. In all cases, previous attempts with EVT with the remodeling technique failed or was technically judged difficult. In all patients, EVT combined stent placement (Leo, Balt, Montmorency, France) across the aneurysm neck and subsequent coiling of the sac. Aneurysms were located on the carotid siphon (n = 9), the internal carotid artery bifurcation (n = 1), and the vertebral artery (n = 1). Aneurysms diameter size varied from 3 to 45 mm. Clinical outcome was assessed with the Modified Glasgow Outcome Scale. RESULTS: EVT was successfully performed and led to an excellent outcome in all patients. The stent could be navigated within cerebral arteries without any exchange procedure. Thanks to its retractability, the stent could precisely be positioned in all cases. Angiographic results consisted of 9 complete occlusions and 2 incomplete occlusions in 2 giant aneurysms. No procedure-related complication occurred. CONCLUSION: The Leo stent appears very useful for EVT of wide-necked intracranial aneurysms. The advantage of this stent is the possibility to reposition it which allows a very precise positioning across the aneurysm neck.

Matrix Detachable Coils for the Endovascular Treatment of Intracranial Aneurysms. Analysis of Early Angiographic and Clinical Outcomes

Background and Purpose— Endovascular coil embolization has become an accepted alternative for the treatment of intracranial aneurysms. The purpose of this study was to evaluate the clinical safety and the angiographic stability of aneurysm occlusion with a new class of biologically active platinum coils after a 6-month period. Methods— Twenty-five patients with 25 intracranial aneurysms were treated by selective embolization with a new coated bioactive coil (Matrix; Boston Scientific Neurovascular). Matrix coils were used alone in 6 patients and in combination with Guglielmi detachable coils (GDCs; Boston Scientific Neurovascular) in 19. Angiographic results, procedure-related complications, and adverse neurological events during the follow-up period were recorded. Magnetic resonance angiography was performed at 6 months in all patients. Results— Initial angiographies demonstrated complete occlusion in 17 patients, residual neck in 7, and a persisting aneurysm in 1. The clinical follow-up showed stable results in all patients. The grade of aneurysm occlusion at 6 months improved in 4 patients, remained stable in 15, and deteriorated in 6. Three patients needed retreatment because of a major aneurysm recanalization. Angiographic recurrences in cases of aneurysms treated with a combination of Matrix coils and GDCs occurred within the expected range for bare platinum coils. Two of 3 patients needing retreatment had been treated with Matrix coils alone. Conclusion— Stable results were obtained predominantly when Matrix coils were combined with bare platinum coils. A prospective, randomized study is necessary to assess the potential benefit of Matrix coils for patients treated by endovascular techniques.

Intracranial Arteriovenous Malformation : Time-resolved Contrast-enhanced MR Angiography with Combination of Parallel Imaging, Keyhole Acquisition, and k-Space Sampling Techniques at 1,5 T

PURPOSE To prospectively compare the agreement between digital subtraction angiography (DSA) and time-resolved magnetic resonance (MR) angiography with sensitivity encoding (SENSE) in combination with keyhole acquisition and contrast material-enhanced robust-timing angiography (CENTRA) k-space sampling techniques for the characterization of intracranial arteriovenous malformations (AVMs). MATERIALS AND METHODS The institutional review board approved the study; informed consent was obtained from all patients (or their parents). Twenty-eight patients (15 male, 13 female; mean age, 38.6 years; age range, 16-61 years) with 29 previously diagnosed, untreated intracranial AVMs who were referred for stereotactic gamma knife radiosurgery were evaluated. Preinterventional imaging included intraarterial DSA and time-resolved MR angiography. The time-resolved MR angiography sequence included SENSE with a 1.5-T imager and was optimized by applying keyhole acquisition and CENTRA techniques. Time-resolved MR angiograms were reviewed by two independent raters and compared with DSA images with regard to arterial feeders, nidus size, and venous drainage. kappa Statistics were applied to determine interobserver and intermodality agreement. RESULTS MR angiography enabled time-resolved (1.7 seconds per volume) visualization of cerebral vessels from axis to vertex at high spatial resolution (true voxel size, 1 x 1 x 2 mm). All 25 nidi detected at intraarterial DSA were visualized at time-resolved MR angiography. Intermodality agreement was excellent for arterial feeders (kappa = 0.91; 95% confidence interval [CI]: 0.786, 1.000) and venous drainage (kappa = 0.94; 95% CI: 0.814, 1.000) and was good for nidus size (kappa = 0.76; 95% CI: 0.562, 0.950). CONCLUSION The agreement (good to excellent) between time-resolved MR angiographic and DSA findings suggests that time-resolved MR angiography is a reliable tool for the characterization of intracranial AVMs with respect to arterial feeders, nidus size, and venous drainage.

Contrast-enhanced MR angiography of the craniocervical vessels: a review

Abstract The use of MR angiography (MRA) with injection of contrast medium enables imaging of a large volume with a very short acquisition time, providing angiographic images similar to those obtained with catheter angiography. This makes possible investigation of patients in the acute phase of stroke, with examination of the entire length of the cervical arteries from the aortic arch to the circle of Willis. However, the parameters of the sequence must be carefully chosen to optimise image quality, with a compromise between spatial resolution, acquisition time and image contrast. An overview of the technical aspects is presented, including current developments. Different protocol strategies are discussed, including their advantages and limits. Finally, we review the preliminary results of contrast-enhanced MRA for assessment of atherosclerotic lesions of supra-aortic vessels.

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 (&kgr;=0.96) with only 4 discrepancies between both examiners. Comparison between CE-MRA and DSA showed an excellent agreement between techniques (&kgr;=0.93). Of the 21 with residual necks described on DSA, 20 were seen on CE-MRA. CE-MRA detected all 19 residual aneurysms. Conclusion— 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.