Transient global amnesia associated with cerebral angiography performed with use of iopamidol.
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Adult↗
Biomedical subjects
R Ethier
Publications and source records attributed to R Ethier.
[Sub-callus epidermoid cyst. A case report].
The cranio-encephalic epidermoid cysts are rare tumors. These lesions are extra-axial and can occur at the infratentorial or supratentorial level. The epidermoid cysts are classically in contact with the base of the skull, and less often intraventricular; the other locations are exceptional. Because of their CT aspect (hypodense lesion, rarely isodense, well defined, without contrast enhancement, and without surrounding edema) and MR aspect (in more than 70% of the cases: more or less homogeneous lesion, hypointense in T1 and hyperintense in T2), the authors believe that it is possible to suggest such a diagnosis even with an atypically located case. We report the case of an epidermoid cyst located between the corpus callosum and the falx cerebri.
Aged↗
MR of deep cerebral venous thrombosis.
Two cases of deep cerebral venous thrombosis are presented with specific reference to the CT and MR findings. The MR findings are discussed, with comparison to the findings of superficial cerebral sino-venous occlusion.
Adult↗
Modeling of therapeutic dialysis of cerebrospinal fluid by epidural cooling in spinal cord injuries.
Paraplegias of traumatic origin may be classified as primary or secondary. Secondary traumatic paraplegia (STP) is believed to result from an autodestructive process. Different authors have published results supporting or contradicting the therapeutic effects of durotomy alone or associated with exposed spinal cord and perfusion with a saline solution at normal or cold temperatures. It appears that although decompression and open dialysis might be beneficial, the surgical trauma over the injured region is detrimental. A method of local epidural spinal cord cooling has been developed and successfully used to treat STP. With this method, no surgical injury or damage is imposed on the dura, cerebrospinal fluid (CSF), or spinal cord. Furthermore, several of the beneficial effects attributed to hypothermia in the traumatized area are evident, including reduction of metabolic demands, edema, swelling, vasospasm, and blood pressure. Aware of the benefits that dialysis may have in STP, as well as of the encouraging results obtainable with local epidural spinal cord cooling, we hypothesized that this method of hypothermia may in some way trigger CSF dialysis. Based on this hypothesis, a model was developed approximating the behavior of the CSF in the situation where a cold source is applied to the dura. Using dimensionless analysis techniques, we predict that CSF under the cooled region of the dura undergoes convective motion, even in adverse situations where the spinal cord has swollen. Under steady-state conditions, the moving fluid forms several Bénard cells directly under the cold source. The size of these Bénard cells was estimated. The range of probe temperatures at which convective flow is generated was considered, as well as the relative benefits of hypothermia versus flow. Results of more rigorous analysis are discussed.
Cerebrospinal Fluid↗
Metrizamide compared with iohexol for cervical myelography: a double-blind study.
A double-blind comparative study of iohexol and metrizamide for use in cervical myelography through lumbar puncture was carried out in a group of 30 patients. No difference was found in the quality of radiographic examinations of the cervical or lumbar regions nor in the postmyelographic computed tomographic examinations of the cervical spine. The overall incidence of side effects was significantly higher in the metrizamide group (93.4%) than in the iohexol group (40%) (p = 0.002). The differences in incidence of nausea (53% in the metrizamide group compared with 13% in the iohexol group) and vomiting (46.6% with metrizamide, 6.6% with iohexol) were also significant (p = 0.02). Pyramidal signs and seizures occurred only after metrizamide myelography.
Adult↗
Superselective cerebral arterial infusion of BCNU in high-grade glioma: the radiologist's point of view.
Thirty-two patients suffering from high-grade glioma were candidates for superselective cerebral arterial infusion of 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU) after surgery and radiation therapy. There were 74 catheterizations using an 8-French guiding catheter through which a 2.5-French balloon catheter was placed into the main arterial trunk feeding the tumor. Eleven procedures were abandoned because of arterial spasm with a transient neurological deficit or because of prolonged catheterization time. Sixty-three infusions of BCNU were done, each lasting three hours. Eighty-one percent of patients showed stabilization or improvement on computed tomographic (CT) scans five weeks after treatment. We thus demonstrate the safety of supraophthalmic catheterization, the feasibility of prolonged catheterization, and the relative effectiveness of low doses of BCNU infused over a long period of time in the treatment of cerebral gliomas.
Brain Neoplasms↗
Magnetic resonance imaging in temporal lobe epilepsy: pathological correlations.
A retrospective single-blind study assessing the value of magnetic resonance imaging (MRI) in 48 patients treated surgically for temporal lobe epilepsy was carried out. The imaging findings were correlated with the surgical findings in all cases. Abnormal MRI signals were detected in 34 of 48 (71%) epileptic patients and in 3 of 48 (6.2%) normal or disease control subjects. Twelve patients had structural foreign-tissue lesions, all detected by MRI. Of 14 patients with severe gliosis of the neocortex and/or mesial temporal structures, 11 had abnormal MRI scans. In patients with mild or moderate gliosis of mesial temporal structures, 6 of 12 had abnormal MRI scans. These results indicate that MRI is a sensitive technique for localizing foreign-tissue lesions, mesial temporal sclerosis, and gliosis in patients with intractable temporal lobe seizures.
Adolescent↗
Anatomical interpretation of MR scans of the brain.
A stereotactic method of brain localization is applied to magnetic resonance imaging for the interpretation of brain structures. This proportional grid system developed by Talairach is based on two intracerebral structures, the anterior and posterior commissures. It takes into account individual variations in brain size and shape. In an experimental study on cadavers we demonstrated that his system permitted accurate identification of cortical structures on CT scan. In this paper, we describe its application to MR. It provides, on a routine basis, a simple reliable method of anatomical interpretation. The use of this grid system is made easier by the fact that both commissures are seen on midsagittal MR scans.
Brain↗
Choroid plexus papilloma: magnetic resonance, computed tomography, and angiographic observations.
Choroid plexus papillomas are rare intracranial neoplasms that are generally benign in nature. They are seen in both children and adults and have a male preponderance. Magnetic resonance imaging, a noninvasive diagnostic tool, demonstrated the intraventricular location and the surrounding anatomy with striking clarity, more effectively than angiography and computed tomography scanning.
Adult↗
[Integration of digital angiography, magnetic resonance, x-ray computed tomography and positron emission tomography in stereotaxy].
Consecutively to drastic changes which occurred in cerebral imagery techniques, we have developed a stereotactic apparatus and system based on the integration of several new techniques allowing visualisation of the brain: tomodensitometry (TDM), digital subtraction angiography (DSA), magnetic resonance (MR) and positron emission tomography (PET). TDM, DSA and MR can be performed in stereotactic conditions with the apparatus in situ. They give the computer the anatomic references necessary for all calculations. MR and PET images obtained without stereotactic apparatus can also be integrated into the stereotactic study at the condition that DSA was formerly performed in stereotactic conditions, i.e. with the apparatus in situ. The visualisation of the corpus callosum makes this integration possible. An optimal definition of cerebral tumors or target-structures for intracerebral electrode recording is thus obtained.
Brain Diseases↗
CT findings in late-onset epilepsy.
We reviewed the CT findings of 387 patients with new-onset seizures after the age of 50. Seizures were generalized in 212 patients, focal in 160, and indeterminant in 15. CT scanning revealed cerebral atrophy in 113 cases, ischemic lesions in 75, cerebral neoplasms in 20, and no abnormality in 177 cases. Tumours were found in only three patients with generalized seizures, and all three had focal neurological deficits at the time of CT diagnosis, while 17 neoplasms were discovered in patients with a focal seizure disorder. The majority of patients with late-onset epilepsy have a normal CT scan with cerebral atrophy being the most common abnormality detected. Cerebral vascular disease appears to be the most frequently identified cause of late-onset epilepsy, while cerebral neoplasms are uncommon.
Age Factors↗
Combined use of digital subtraction angiography and MRI for radiosurgery and stereoencephalography.
The authors report their experience with the combined use of digital subtraction angiography (DSA) and magnetic resonance imaging (MRI) for the stereotactic placement of intracerebral electrodes in epilepsy and for the radiosurgical treatment of otherwise inoperable arteriovenous malformations of the brain. Both imaging techniques, when used in conjunction, have been found most useful and complementary. For deep electrode placement, they permit optimal visualization of the cerebral structures to be reached by the electrode array while allowing the avoidance of vessels in the vicinity. For radiosurgery of arteriovenous malformations, DSA provides optimal visualization of the feeders and of the malformation itself, while the MRI reveals the cerebral structures to be spared by the photon beam of the linear accelerator. A discussion of their respective roles is presented, with the specific question as to whether MRI alone could be used for both procedures.
Cerebral Angiography↗
Magnetic resonance imaging of cerebral arteriovenous malformations.
Magnetic resonance imaging (MRI) was performed in 15 patients with small to very large supratentorial arteriovenous malformations (AVMs). Unlike non-contrast infused computed tomographic (CT) scanning, MRI demonstrated the AVM in all cases. The nidus had a characteristic honeycomb appearance, and in all cases feeding arteries and deep or superficial draining veins were demonstrated without intervening bone artifact. The relationship of the AVM to surrounding cortical areas, deep nuclei, important white matter tracts, and the ventricular system was well appreciated. These characteristics make MRI useful for the diagnosis of cerebral AVMs and add to the accuracy of systems that grade operability on the basis of the angiographic demonstration of size, location, depth, arterial supply, and venous drainage. In many cases, based on the MRI appearance of the AVM and its relationship to important brain structures, the lesion can be deemed inoperable or unsuitable for other forms of treatment, making angiography unnecessary. Thus, the superior anatomical and morphological resolution of MRI, the lower false-negative rate, and the independence from x-ray and contrast material make MRI more useful than CT scanning for the diagnosis of AVMs and as an aid in the management of specific cases.
Adult↗
Diagnostic potential of magnetic resonance in cases of foramen magnum meningiomas.
Meningioma is a histologically benign tumor that is second in frequency only to gliomas among primary intracranial tumors. Its extracerebral development and generally clear demarcation from the brain does not make it easier to detect on magnetic resonance (MR) scanning. Only 2 to 3% of meningiomas occur in the foramen magnum, and these tumors are often clinically misdiagnosed. We discuss four cases of foramen magnum meningioma, with emphasis on MR scanning.
Adult↗
Acute epidural hematoma following decompressive surgery of a subdural hematoma.
We report a patient with acute epidural hematoma diagnosed using computed tomography shortly after decompressive surgery of a contralateral subdural hematoma not resulting in clinical evidence of improvement. The patient underwent successful second emergency decompressive surgery. Prompt recognition is essential for a successful outcome, and poor recovery, when not otherwise anticipated, should alert immediately to a possible contralateral hematoma.
Craniocerebral Trauma↗
CT, MRI, and angiography of venous angiomas: a comparative study.
Seventeen venous angiomas in 16 patients were evaluated radiologically at the Montreal Neurological Hospital. Radiologic investigations included contrast-enhanced computed tomograms (CECT) in 15 patients, cerebral angiograms with a long venous phase study in 15, and magnetic resonance (MR) imaging with a spin-echo pulse sequence technique in six. CECT revealed abnormalities including six nodular nonspecific enhancing lesions and nine enhanced draining veins, whereas plain CT revealed intracerebral hemorrhages in four patients and calcification in one. All the angiograms showed the characteristic pattern of venous angiomas consisting of medullary veins converging to a large draining vein during the late venous phase. All six patients examined by MR showed abnormal vascular structures; parenchymal hemorrhages were present in two patients. In five patients with venous angiomas, medullary veins converging to a large draining vein were demonstrated as echo-void curvilinear structures. In two patients, the increased signal from medullary veins in long echo delay sequences was suggestive of a slow venous flow rate. Demonstration of the venous nature of the malformation may, in the future, obviate the need for angiography.
Adult↗
Rhinoplasty: a CT-scan analysis.
In order to assess the postoperative consequences of various rhinoplasty techniques, CT scans were done in 35 patients having a rhinoplasty operation. This series can be subdivided into those having preoperative and postoperative scans at both 2 days and 6 months (15 patients), a postoperative scan only at 48 hours (10), or a long-term postoperative scan at a mean of 12 months (10). Preoperative analysis indicates that a wide variation exists in lateral nasal wall anatomy and angulation. Surgically, the lateral nasal walls undergo limited medial movement, with tilt a significant component. Postoperatively, extensive remodeling can occur, and virtually all osteotomies are healed by osseous union at 6 months. Future application of CT scans in severely deviated noses may be justified.
Adult↗
Embolization with temporary balloon occlusion of the internal carotid or vertebral arteries.
Functional vascular anastomoses at the base of the brain allow for temporary occlusion of the carotid or vertebral arteries. Six embolizations with temporary balloon occlusion of the internal carotid or vertebral artery are reported. Polyvinyl alcohol was the embolic material in all cases and all procedures were performed using digital angiography. The size of the embolic particles and the positioning of the balloon related to the branches of the occluded vessel is discussed.
Adolescent↗