✓ Subacute posttraumatic ascending myelopathy is a rare disorder, unrelated to syrinx formation or mechanical instability, that may gradually emerge within the first 1 to 2 weeks after a spinal cord injury. The authors describe three patients with this syndrome and discuss its possible causes as well as its clinical presentation, imaging characteristics, treatment, and patient prognosis.

Introduction: Chondromas are rare intracranial tumors. The authors present two cases of intracranial intradural chondroma, one originating from the falx cerebri and the other from the dura mater of the convexity. Method and Results: Diagnostic procedures, including magnetic resonance imaging, and surgical findings are described. In both cases, pre-operative diagnosis could have been at least suspected, and the tumor was completely removed, without recurrence after a follow-up of many years. The pathogenesis and pathological findings are discussed, and cases from the literature are reviewed. Conclusion: Benign intradural chondroma has a good prognosis, with no recurrence after surgical excision in most cases. RESUME: Presentation de deux cas de chondrome intracranien et revue de la litterature. Introduction: Les auteurs pr6sentent 2 cas exceptionnels de chondrome intracranien intradural, une tumeur intracranienne particulierement rare. Un cas originait de la faux du cerveau et l'autre de la dure-mere de la convexity. Methode et Resultats: Les donndes d'imagerie, incluant la resonance magn&ique nucl6aire, de raeme que les donnees chirurgicales sont presentees. Dans les deux cas, le diagnositc pre-operatoire pouvait etre fortement suspecte\ et une excision complete de la 16sion a ete pratiqufie, sans signe de r^cidive apres une periode de suivi de nombreuses annfies. La pathog6nese et la pathologie sont discuses, et les auteurs font une revue breve des cas de la literature. Conclusion: Le chondrome intradural b6nin est une tumeur a bon pronostic avec un risque tres faible de recurrence apres excision chirurgicale complete.

We demonstrate the use of integrated multi-modality data (MRI, MRA, DSA, PET and live video) and 3-D stereoscopic imaging in the context of image-guided neurosurgery. We consider here the integration of anatomical data (MRI), vascular data (DSA and MRA) and functional data (PET) derived from the patient undergoing the surgical procedure. In addition live video images are merged with renderings of the data stored in the computer.The integration of multimodality data provides the surgeon with interactive and intuitive access to a comprehensive overview of the brain structures on which surgery is being performed. Ready access to this information enhances the surgeon's ability to avoid critical vessels and structures of functional significance.

A new CT-guided stereotactic system using tridimensional angiography is described. The trajectory is directly determined from a moving probe (''floating line'') which appears on a tridimensional stereoscopic angiography, permitting the choice of an avascular trajectory with a high degree of accuracy. The authors have done 84 probe implantations with an excellent diagnostic and therapeutic rate and no morbidity-mortality.