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In recent years there has been a rapid expansion in both the diagnostic modalities and management of vascular diseases of the head, neck, brain and spinal cord. This has resulted in new ideas in vascular physiology, pathophysiology, treatments for arteriovenous malformations, aneurysms, occlusive arterial disease, imaging the cerebral circulation and also the development of neuroprotective substances. Emerging concepts in neurovascular diseases are multidisciplinary in their approach; neuroradiology has become a significant contributor to that multidisciplinary discussion. A tremendous accumulation of clinical data has accompanied this development. However little research in the biological and genetical field, leading to Ph.D. theses, has been achieved by interventional neuroradiologists. Such phenomenon is both acceptable and comprehensible in a highly technical and stressful newly opened surgical field. However crystallization of that experience into research laboratories and specialized teaching must be developed. Joint efforts to learn with sister specialties the field of fundamental research would further enhance our place within the neurosciences. It is insufficient for our practice to rely strictly on tool research or physiopathogical models to justify what is already done, without exploring the unknown.

International audience; PURPOSE: Our aim was to study the fractional anisotropy (FA) variations and the fiber tracking (FT) patterns observed in patients with myelitis. MATERIAL AND METHODS: Fifteen patients with symptomatic myelitis and 11 healthy subjects were prospectively selected. We performed T2-weighted and diffusion tensor imaging on a 1.5T MR scanner. FA and apparent diffusion coefficient maps were computed in both healthy subjects and patients. In each patient, we performed FT to study pathologic aspects on this imaging method. FA data were analyzed by using z-scores. RESULTS: For the healthy subjects, averaged FA values ranged from 0.745 to 0.751. All abnormal areas seen on T2-weighted imaging had a significantly decreased FA value. In 9 patients (60%), FA maps showed decreased FA areas, whereas T2-weighted imaging findings were normal. These areas matched the neurologic deficit in 33%. Eighty percent of patients had multiple decreased FA areas. Five patients (33%) had increased FA values in normal T2-weighted areas. CONCLUSION: We observed specific FA and FT pattern variations in patients with myelitis.

PURPOSE: Our aim was to study the fractional anisotropy (FA) variations and the fiber tracking (FT) patterns observed in patients with myelitis. MATERIAL AND METHODS: Fifteen patients with symptomatic myelitis and 11 healthy subjects were prospectively selected. We performed T2-weighted and diffusion tensor imaging on a 1.5T MR scanner. FA and apparent diffusion coefficient maps were computed in both healthy subjects and patients. In each patient, we performed FT to study pathologic aspects on this imaging method. FA data were analyzed by using z-scores. RESULTS: For the healthy subjects, averaged FA values ranged from 0.745 to 0.751. All abnormal areas seen on T2-weighted imaging had a significantly decreased FA value. In 9 patients (60%), FA maps showed decreased FA areas, whereas T2-weighted imaging findings were normal. These areas matched the neurologic deficit in 33%. Eighty percent of patients had multiple decreased FA areas. Five patients (33%) had increased FA values in normal T2-weighted areas. CONCLUSION: We observed specific FA and FT pattern variations in patients with myelitis.

International audience; PURPOSE: Our aim was to study the fractional anisotropy (FA) variations and the fiber tracking (FT) patterns observed in patients with myelitis. MATERIAL AND METHODS: Fifteen patients with symptomatic myelitis and 11 healthy subjects were prospectively selected. We performed T2-weighted and diffusion tensor imaging on a 1.5T MR scanner. FA and apparent diffusion coefficient maps were computed in both healthy subjects and patients. In each patient, we performed FT to study pathologic aspects on this imaging method. FA data were analyzed by using z-scores. RESULTS: For the healthy subjects, averaged FA values ranged from 0.745 to 0.751. All abnormal areas seen on T2-weighted imaging had a significantly decreased FA value. In 9 patients (60%), FA maps showed decreased FA areas, whereas T2-weighted imaging findings were normal. These areas matched the neurologic deficit in 33%. Eighty percent of patients had multiple decreased FA areas. Five patients (33%) had increased FA values in normal T2-weighted areas. CONCLUSION: We observed specific FA and FT pattern variations in patients with myelitis.

International audience; PURPOSE: Our aim was to study the fractional anisotropy (FA) variations and the fiber tracking (FT) patterns observed in patients with myelitis. MATERIAL AND METHODS: Fifteen patients with symptomatic myelitis and 11 healthy subjects were prospectively selected. We performed T2-weighted and diffusion tensor imaging on a 1.5T MR scanner. FA and apparent diffusion coefficient maps were computed in both healthy subjects and patients. In each patient, we performed FT to study pathologic aspects on this imaging method. FA data were analyzed by using z-scores. RESULTS: For the healthy subjects, averaged FA values ranged from 0.745 to 0.751. All abnormal areas seen on T2-weighted imaging had a significantly decreased FA value. In 9 patients (60%), FA maps showed decreased FA areas, whereas T2-weighted imaging findings were normal. These areas matched the neurologic deficit in 33%. Eighty percent of patients had multiple decreased FA areas. Five patients (33%) had increased FA values in normal T2-weighted areas. CONCLUSION: We observed specific FA and FT pattern variations in patients with myelitis.

International audience; Spinal cord astrocytomas are rare neoplasms that can result in alteration of the spinal cord structural integrity, which can be assessed by using diffusion tensor imaging methods. Our objective was to visualize the deformation of the posterior spinal cord lemniscal and corticospinal tracts in 5 patients with low-grade astrocytomas compared with 10 healthy volunteers by using 3D fiber-tracking reconstructions.

Summary: Primary cartilaginous lesions of the larynx are relatively uncommon. We present a case of bilaterally pseudocystic lesion of the thyroid cartilage that demonstrated progressive calcification. Pathologic analysis showed features suggesting a dystrophic lesion with no evidence of malignancy. We hypothesize that repetitive microtrauma related to muscular overuse probably led to inflammatory changes at tendinous insertions on the laryngeal cartilage and resulted in dystrophic ossification of the laryngeal cartilage.

Urological procedures are hazardous for hemophilic patients. The aim of this work is to report the treatment of 22 hemophilic patients in order to define prognosis factors and treatment options.22 patients have been treated: 8 had severe hemophilia, 5 A (FVIII1%), 3 B (F IX1%), 2 had moderate hemophilia A (FVIII 2 to 6%) and 10 minor hemophilia A (F VIII 7 to 30%). Two had acquired hemophilia with auto-anti-FVIII antibodies (ab). Four patients were HIV+. Eighteen patients were first referred to our hospital, and 3 were transferred from an other institution for persistent hematuria: one with anuria, one after bladder neck incision, and the other following suprapubic prostatectomy.For patients without FVIII ab, a sufficient level of FVIII or IX (60%), could be achieved pre-operatively and maintained post operatively (4 to 20 days, according to the surgical procedure) by injections of FVIII, FIX or by injections of desmopressin. For one haemophilia A patient with anti-F VIII ab, transferred for uncontrollable bleeding after bladder neck incision, selective arterial embolization was successful. But for 2 patients with acquired haemophilia, improvement of the coagulation was insufficient, with human or porcine FVIII, activated prothombic complex concentrates or recombinant activated FVII. In spite of surgical procedures and arterial embolizations the 2 patients died.The urological treatment of haemophilic patients needs to be performed in specialised centers. For patients without FVIII ab, classical urological procedures can be performed. But for patients with FVIII ab when alternative treatments (radiotherapy, LHRH agonists) can be used, the surgical procedures must be delayed; in emergency if hemostasis cannot be achieved arterial embolization could be useful.

Endovascular management of intracranial arterial aneurysms (AA) is well described and performed by many teams. The aim of this work is to review a series of consecutive cases treated in our institution and to compare to the data available in the literature. 225 AA were seen in Bicêtre between 1993 and 1998 in 203 patients. 201 of them (in 180 patients) were treated by our group. The endovascular treatment, its indications, results and complications have been reviewed and studied. The clinical follow-up of the patients has been evaluated. A female dominance was noted (64.5%) with a mean age of patients of 44.3 years. 65.6% of patients were treated in the acute phase after intracranial haemorrhage, 72% of them being Hunt and Hess grade 1 or 2. Most of these AA (73.6%) were located in the anterior circulation. In 86.1% of cases the AA was smaller than 10 mm. 85.6% of the AA needed only one session of endovascular therapy. No mortality occurred in the group of unruptured AA. Overall management mortality was 11% in ruptured AA (3.5% in HH1-2, 30.3% in HH3-5).Technical or transient complications occured in 11.6% of cases, but permanent morbidity was seen in 3.1% of cases. Control angiograms were performed 3 months and one year after therapy. In doubtful cases a control at 6 months was also performed. 100% occlusion rate was noted in 60.8% of cases; 22.8% of AA were occluded between 90-99%, and 13.3% between 80-90%. Only 3.1% of AA had an occlusion rate of less than 80%. One patient with a ruptured basilar tip AA which was partially coiled regrew and rebled three months after. The patient declined the recommended complementary surgery. Clinical follow up of patients with ruptured AA treated by embolisation shows satisfactory results with 8.5% of GOS 1-2, 3.4% of GOS 3-4, and 11% of GOS 5 (mortality). Overpacking of the AA may not be necessary to protect patients from (re)bleeds over time. The related technical risks and increased costs of dense overpacking do not seem justified. Secondary thrombosis of the ruptured AA after coiling is more often seen than coil compaction. Analysis of the AA architecture and recognition of false aneurysms are mandatory in order to obtain good clinico-morphological logical results.

Recently several articles or comments have appeared regarding the opportunities for teaching offered by the web. Most of these approaches focused on the teachers' advantages; some, however, discussed the trainees' situation {Becker G.S. (former Nobel laureate): How the web is revolutionizing learning. Business week/dec. 27.11; 1999). The most constant remarks deal with: -the remote situation of the actors involved “The growth of the Internet may revolutionize this system by allowing 'distance learning\ in which teachers and students interact closely even though they are separated both physically and in time”. -the time saved in having locally made sessions easily organised “The key economic advantage of distance learning over traditional on-site schooling is that it saves students time. The value of the time spent learning is the principal cost of investment in human capital among adults with even moderate earnings”. “Online instruction also allows greater time flexibility for students to interact with course materials, “chat” with other students, take quizzes, and submit written papers”.... “Chat rooms” encourage group discussions among students and teachers and reduce the feeling of isolation fostered by sitting alone in front of a computer”. Attention is paid to continuing education rather than initial teaching in most instances “Distance learning appeals mainly to adults who want to take courses toward a bachelor's or master's degree`, or maintain and upgrade job skills that have grown dated”. The teachers' point of view is sometimes unpredictable and gross “The spread of faster and, ultimately, of broadband access to the Web enables online teachers to move about and gesticulate as if they were in front of live audiences”. “Internet instructors can also customize their question and discussion to fit the needs of individual students”. The commercial aspect is not far from all these educational considerations “WORK FARE. For example, to better assess and manage their considerable investments, financial officers of large companies need to understand the use of modern options markets to reduce risks. And growing numbers of men and women in many nations want to learn to read and write English, the global language of trade and commerce”. It sounds like global thinking, and sheds doubts on future innovation if the model applied is unique: one model, one market, one language, one education. Are there any forms of education that create more dependence than independence? “Distance learning offers an opportunity to outsource teaching to specialized companies without taking employees away from their work”. Between market opportunities and professional actors and bodies, joint ventures will take the pragmatic aspect of university budget problems to contribute to “modern” solutions. “Meanwhile, for-profit companies have begun to provide online instruction in numerous subjects. To gain faster acceptability and recognition, some of these companies have entered into cooperative arrangements with accredited colleges and universities”. The author's analysis revolves almost exclusively around the financial benefits of teaching from a distance. One could even say that teaching disappears in this article, leaving only the discussion on the financial benefits of the web. Teaching is presented as a one-way process : information is broadcast worldwide to several individual sites, where groups of students are left on their own to interact with the teaching material and among themselves after the “course” - not unlike the Tupperware organization? The advantage of worldwide broadcasting of teaching material which would have otherwise only benefited a few is clear. But the teacher is not just an eloquent “gesticulating” tumbler whose supposedly educational mimics could help teach audiences throughout the world. The fact that teaching may be one-on-one (although forbidden by law), at best (legally) in a small classroom situation, in a 300-seat amphitheater, in an auditorium of several thousands, or on a world scale, calls for specific techniques but is based on the same fundamental principles. The goal and the talent of the teacher is to adapt to his audience and to adjust to the inflexions of collective moods so that his first objective may remain to enrich the audience. Enriching the audience is certainly not incompatible with personal financial benefits. But both principles should be placed in that priority. It is a well-known fact that the larger the audience, the more difficult it becomes to adapt the educational discourse. When the audience exceeds an amphitheater of 300, only a few teachers can really adjust their course to a more or less resistant group. Beyond those numbers, or for most lecturers teaching simply becomes information sharing. Pedagogy is not a marketing or communication technique. The idea of having groups of students is interesting, on the condition that they are “chaired” by a professional teacher who will organize and lead the discussions and the interaction with the teaching material. If self-teaching was so easy, people would have been learning on their own for a long time in libraries or with television programs. But it simply doesn't happen. Although we live in a “global system”, it is enclosed within the boundaries defined by legal and ethical standards. The object of teaching is also to help people understand these rules, to conceptualize them and to share the benefits of the methods, so that information may secondarily become true knowledge, and a source of liberty and progress. Information is but material for the teacher, a vehicle for education. The teacher as described by Becker represents a single educational scheme that has neither the means nor the time, and probably not the training to consider the cultural differences of an international audience. Becker claims one can deliver raw material to students in a user-friendly way, which doesn't mean it is educationally efficient. He presupposes that by discussing the material, it will automatically become fertile sediment or a pleasant discourse. However students, whether on their own or in groups, are not all systematically or always intelligent and truth will not necessarily spring from their conversations. The broadcast conferences must be relayed locally by another teacher. Just as the patient must remain at the center of discussions in health and hospitalization systems, so the student and the teaching of knowledge must remain at the center of discussions in educational techniques. The web is an incredible resource for educational projects. It offers educational documents just as a large library does. If for a given topic there are for example five different books, the key is not in the book itself but in the authors. The availability of all five books anywhere on the planet at any time is only a bookstore's stock problem resolved. The decrease in time to obtain such information does not reduce the time needed to learn it, and probably even to interpret it. Understanding remains an intellectual process and not a technological challenge.

A simplified map of the cervicovertebralcarotid channels is presented with a description of the arterial supply to the cervical nerves. The aim of the work is also to open the field for endovascular therapy of malignant lesions distal to carotid ligation with greatest security, and to discuss a new approach to some upper cervical neuropathies.

The goal of preoperative embolization of intracranial meningiomas is to facilitate their surgical removal by reducing tumor vascularity and decreasing blood loss during surgery. This study is based on personal experience with about 100 embolized meningiomas and on the experience of others. Embolization is performed during the same session as diagnostic angiography. The appropriate embolic materials (absorbable or nonabsorbable) are chosen according to the location of the tumor, the size of the feeding arteries, the blood flow, and the presence of any potentially dangerous vessels (dangerous anastomoses between external carotid artery and internal carotid or vertebral arteries, arteries supplying the cranial nerves). Preoperative embolization appeared to be very useful in large tumors with pure or predominant external carotid artery supply (convexity meningiomas), in skull-base meningiomas, and in middle fossa and paracavernous meningiomas. It was also useful in falx and parasagittal meningiomas receiving blood supply from the opposite side and in posterior fossa meningiomas. CT low densities demonstrated after embolization did not always correlate with necrosis on microscopic examination, and large areas of infarction could be found despite normal CT. Embolic material was found on pathologic examination in 10%-30% of cases; fresh or recent ischemic and/or hemorrhagic necrosis consistent with technically successful embolization was demonstrated in 40%-60% of cases. With careful technique complications are rare.

Two arteries arising from the orbit, coursing through the superior orbital fissure to supply the cavernous region and the tentorium, may be identified at angiography. The radiologic and anatomic appearances of these arteries are discussed on the basis of the embryologic development.

BACKGROUND AND PURPOSE: Brain hypervascular diseases are complex and induce hemodynamic disturbances on brain parenchyma, which are difficult to accurately evaluate by using perfusion-weighted (PWI) MR imaging. Our purpose was to test and to assess the best AIF estimation method among 4 patients with brain hypervascular disease and healthy volunteers. METHODS: Thirty-three patients and 10 healthy volunteers underwent brain perfusion studies by using a 1.5T MR imaging scanner with gadolinium-chelate bolus injection. PWI was performed with the indicator dilution method. AIF estimation methods were performed with local, regional, regional scaled, and global estimated arterial input function (AIF), and PWI measurements (cerebral blood volume [CBV] and cerebral blood flow [CBF]) were performed with regions of interest drawn on the thalami and centrum semiovale in all subjects, remote from the brain hypervascular disease nidus. Abnormal PWI results were assessed by using Z Score, and evaluation of the best AIF estimation method was performed by using a no gold standard evaluation method. RESULTS: From 88% to 97% of patients had overall abnormal perfusion areas of hypo- (decreased CBV and CBF) and/or hyperperfusion (increased CBV and CBF) and/or venous congestion (increased CBV, normal or decreased CBF), depending on the AIF estimation method used for PWI computations. No gold standard evaluation of the 4 AIF estimates found the regional and the regional scaled methods to be the most accurate. CONCLUSION: Brain hypervascular disease induces remote brain perfusion abnormalities that can be better detected by using PWI with regional or regional scaled AIF estimation methods.

Patients with multiple intradural aneurysms present unique clinical challenges, particularly when presenting with subarachnoid haemorrhage. This study was undertaken to retrospectively review the management of such patients treated at a single institution. Consecutive patients with multiple intradural aneurysms managed at our institution between 1993 and 1999 were studied. The 122 patients had a total of 305 aneurysms. In most patients presenting with subarachnoid haemorrhage, the aneurysm responsible for the bleed could be identified with a fair degree of certainty, as confirmed by subsequent surgical and autopsy findings. Irregularity of the aneurysm (false sac or polylobulation) was the most useful criterion for making this determination. Failure to recognize all aneurysms on the original angiogram remained an uncommon but clinically important problem. Posterior inferior cerebellar and anterior communicating artery aneurysm locations were disproportionately more likely, and para-ophthalmic less likely, to be responsible for the subarachnoid haemorrhage. There was a trend for patients with uncertainty regarding the site of bleeding to have all aneurysms treated, and for cure to be obtained in a shorter time. Surgical and endovascular complication rates and patient outcomes were not dissimilar from what one would expect for single aneurysm patients. During follow-up, we observed a haemorrhage rate from unruptured aneurysms of 1.1% per patient-year of observation, and a de novo aneurysm formation rate of 0.76% of patients per year. In conclusion, we feel that although patients with multiple intradural aneurysms have more complex management issues than those with single aneurysms, good outcomes can be achieved with appropriate use of endovascular and/or surgical therapy. The goal in the acute setting following subarachnoid haemorrhage is recognition of all aneurysms and urgent treatment of the one responsible for the haemorrhage. When there is uncertainty, more than one aneurysm may need to be treated. Decisions on subsequent treatment of remaining unruptured aneurysms must be individualized.

About 20 cases of prenatal diagnosis of vein of Galen aneurysmal Malformation (VGAM) have been described. We present a case diagnosed prenatally by Doppler ultrasonography. Prenatal MRI and postnatal radiological studies including post-treatment MRI and MRA, were carried out.