Temporal lobe epilepsy with varying severity: MRI study of 222 patients.

MRI was performed in 222 consecutive adult patients with temporal lobe epilepsy of varying severity from January 1991 to May 1993. The diagnosis of hippocampal sclerosis was established visually by three independent observers. The accuracy of visual assessment of hippocampal asymmetry was compared with volumetric measurements. Neuropathological correlations were obtained in 63 patients with refractory seizures. Temporal lobe abnormalities were observed in 180 patients (81%) as follows: hippocampal sclerosis in 122 (55%); developmental abnormalities in 16 (7.2%); tumours in 15 (6.8%); scars in 11 (5%); cavernous angiomas in 10 (4.5%); miscellaneous lesions in 6. MRI was normal or showed unrelated changes in 42 patients (19%). Visual assessment correctly lateralised hippocampal sclerosis in 79 of the 84 patients measured (94%). Temporal lobectomy confirmed the MRI data (side and aetiology) in all 63 operated patients. Patients with normal MRI had an older age of seizure onset and were more often drug-responsive than patients with hippocampal sclerosis. MRI showed temporal lobe abnormalities in 81% of epileptic patients with varying severity with good neuropathological correlation. Patients with normal MRI had a less severe form of the disease.

[Magnetic resonance imaging of temporal lobe epilepsy]. / L'imagerie par résonance magnétique de l'épilepsie du lobe temporal.

MR has gained more and more importance in the evaluation of patients with temporal lobe epilepsy (TLE). Until recently, hippocampal sclerosis (which is the most frequent cause of temporal lobe epilepsy, accounting for 50-70% of the cases) could not be identified reliably. Using optimized magnetic resonance imaging techniques, hippocampal sclerosis can now be evidenced in a large proportion of patients with TLE. Tumors (10-15%), developmental abnormalities (5-7%), vascular malformations (mostly cavernous angiomas, 1-5%), and traumatic scars (5-10%) represent the other structural lesions associated with TLE. Studies of large series of patients with intractable epilepsy or with varying severity have shown that in only 8.5% and 20%, respectively, a specific imaging abnormality was not found. Specific MR sequences increase the diagnostic value of MR (coronal images perpendicular to the axis of the hippocampal formations, three-dimensional T1 weighted images, inversion recovery images, volumetry or more specific processes such as T1 and T2 relaxometry or spectroscopy). MR also helps guide placement of intra-cerebral and subdural electrodes in surgically relevant cases. All these results have given greater importance to MR in the definition of the epileptic syndrome of TLE and should probably be integrated in the criteria of international classifications.

[Spinal cord toxoplasmosis and AIDS]. / Toxoplasmose médullaire et SIDA.

Toxoplasmosis is the most common brain parasitic infection in acquired immunodeficiency syndrome (AIDS). Spinal cord localisations are still rare (2 cases with cerebral involvement, 2 cases without). A case of both spinal cord and cerebral involvement is reported. MR imaging was performed because of sensory level (L1). A focal conus medullaris enlargement was seen, iso intense on T1 weighted images. This lesion was hyperintense on T2 weighted sequence, and was homogeneously enhanced after Gadolinium on T1 weighted images. A medullary oedema was noted. A toxoplasmosis treatment was initiated, without corticotherapy. MR imaging performed one month later (D30), while important clinical improvements were seen, pointed out normal thickness of conus medullaris, without enhancement after Gadolinium. Disease lesions in AIDS with focal spinal cord processes are reviewed, and diagnostic work-up is discussed. Spinal cord single lesion, associated or not with brain involvements should be treated as a toxoplasmic infection, with MR imaging follow up. This work up should avoid medullary biopsy, still required in case of treatment failure. Cerebral involvements, with multiples lesions, can mask medullary localisation.

Developmental abnormalities of the medial temporal lobe in patients with temporal lobe epilepsy.

PURPOSE: To evaluate MR temporal lobe malformations and their frequency in patients with temporal lobe epilepsy. METHODS: Two hundred twenty-two consecutive adult patients with temporal lobe epilepsy of varying severity were investigated with 1.0-T or 1.5-T MR units using three-dimensional T1-weighted acquisition protocol. RESULTS: Sixteen patients (7.2%) presented with malformations of the temporal lobe. Four patterns of malformations were encountered: (a) heterotopia (n = 1), lining the temporal horn of the lateral ventricle; (b) focal neocortical dysgenesis (n = 6), which consisted of cortical thickening, poor gray/white matter demarcation, abnormal gyration (n = 5), or limited schizencephaly (n = 1); (c) hippocampal malformations (n = 5), which presented as abnormal hippocampal formation associated with a cyst (n = 2), isolated malformation of the subiculum (n = 1), or bilateral hippocampal malformation (n = 2) consisting of an abnormal shape and a misplaced fimbria; (d) complex malformations of the temporal lobe, combining categories a, b, and c (n = 4). The age at onset, severity of the disease, and occurrence of generalized tonicoclonic seizures were not significantly different between patients with malformations and the entire population of patients with temporal lobe epilepsy. CONCLUSION: MR analysis of temporal lobe malformations allowed a precise determination of the extent of the malformations and the presence or absence of associated hippocampal disease, all of which are of great help in the preoperative evaluation of patients with intractable epilepsy.

Value of magnetic resonance imaging-based measurements of hippocampal formations in patients with partial epilepsy.

OBJECTIVE: To determine the occurrence of magnetic resonance imaging-detected hippocampal atrophy (HA) in patients with partial epilepsy (temporal and extratemporal, cryptogenic, or symptomatic). Magnetic resonance imaging-detected HA has been demonstrated to be both sensitive and specific for hippocampal sclerosis in cryptogenic temporal lobe epilepsy. DESIGN: Patients' hippocampal formations were measured on a computerized system using T1-weighted, 5-mm contiguous magnetic resonance coronal images made perpendicular to the hippocampus long axis. Hippocampal atrophy was defined on the basis of a normative asymmetry index and correlated with the epileptogenic focus defined by clinical, electroencephalographic, and magnetic resonance imaging (apart from HA) localizing data. PATIENTS AND CONTROL SUBJECTS: Seventy patients with intractable complex partial seizures of temporal, extratemporal, or undefined origin and 21 healthy control subjects. RESULTS: Hippocampal atrophy was present in 70% of patients with cryptogenic temporal lobe epilepsy (TLE) (n = 40), 44% of patients with symptomatic TLE (n = 9), 29% of patients with extratemporal epilepsy (n = 14), and 6% of unclassified patients (n = 16). In the cryptogenic TLE category, HA was marked and usually concordant (93%) with electroencephalographic lateralization. Hippocampal atrophy was often mild in the extratemporal epilepsy category. With the use of a wider confidence interval (+/- 3.1 SD instead of +/- 2.2 SD), HA specificity for TLE increased to 93%, HA specificity for lateralizing cryptogenic TLE reached 96%, and HA sensitivity for cryptogenic TLE stood almost unchanged (68%). We found a link between early convulsions and HA occurrence. CONCLUSIONS: Hippocampal atrophy is a marker for TLE. Dual pathologic findings are detected in 44% of symptomatic TLE cases. Mild HA is rarely associated with extratemporal epilepsy. Magnetic resonance imaging-based hippocampal volumetric analysis is a useful method to localize the origin of partial complex seizures.

The commissuro-mamillary plane in MRI of the brain (preliminary communication).

MRI sections of the brain in the coronal plane through the line joining the anterior commissure and the mamillary bodies display the constituent parts of the basal forebrain. The visualisation of the septal nuclei and the anterior columns of the fornix show the importance of this plane in the study of behaviour disorders and amnesic syndromes.

[Scanner-guided puncture biopsy of a lesion occupying the pterygo-maxillary fossa]. / Ponction biopsie guidée sous scanner d'un processus occupant la fosse ptérygo-maxillaire.

A 26-year old male patient was referred to us for impaired mouth opening. Actually, Mr. B. has been followed up for SADAM for 2 years at different hospital services. In view of the ineffectiveness of the treatments administered (occlusal releasing gutter, antiinflammatory agents) and due to occurrence of severe episodes of earache refractory to conventional analgesics, we request that a CT-scan be obtained to evidence the process invading the pterygopalatine fossa. ENT examination and scanner-guided needle biopsy are performed to enable anatomopathological analysis and diagnosis.

The commissuro-mamillary plane in MRI of the brain (preliminary communication)

MRI sections of the brain in the coronal plane through the line joining the anterior commissure and the mamillary bodies display the constituent parts of the basal forebrain. The visualisation of the septal nuclei and the anterior columns of the fornix show the importance of this plane in the study of behaviour disorders and amnesic syndromes.

[The diagnostic importance of different imaging technics in temporomandibular joint dysfunction]. / Apport diagnostique des différentes techniques d'imagerie dans les dysfonctionnements des articulations temporo-mandibulaires.

Various imaging techniques enable to explore the Temporo-mandibular joints (T.M.J.). The physicians prescribing them, must be perfectly aware of the informations they provide as well as their costs, for a judicious formulation of their indications. Conventional radiography is absolutely necessary and, most of the time, sufficient, since it simply permits to evaluate the bony structures. An orthopantomogram and modified Schüller views of each T.M.J., "open mouth" and "closed mouth" will be performed. Conventional tomograms are no longer indicated. They will be abandoned for Computed Tomograms. This examination permits, at a relatively low cost, to analyse a bony abnormality and explore the muscular soft tissues. It may also be possible to assess the meniscus, its position and displacement when the mouth is opened. In fact, if a meniscal or articular pathology is considered, which could result in surgical or endoscopic procedure, it is absolutely necessary to perform: -either an arthro-tomography, with contrast material, -or a magnetic resonance examination. The latter provides perfect anatomical and pathological informations of the joint and meniscus, in an atraumatic fashion for the patient. Its only contraindication is in the cost of the examination. It will be possible to look for a dislocation, a malformation or a structural alteration of the meniscus which could result in a perforation, a rupture of the posterior frenulum, adhesions or joint extravasation. A necrosis or early osteochondritis of the condyle will be ruled out.

[Inter-apophyseal articular synovial cyst of the lumbar spine. X-ray computed tomographic and magnetic resonance imaging correlation. Apropos of 2 cases]. / Kyste synovial articulaire inter-apophysaire du rachis lombaire confrontation tomodensitométrique et imagerie par résonance magnétique. A propos de 2 cas.

Two patients presenting with L5 radiculagia were investigated by CT scan imaging. The origin of the pain was determined with certitude as arising from intraspinal development of an interapophyseal synovial cyst. Examination of the two cases by MR imaging provided conflicting results: in one patient images obtained by MR were not contributive and the synovial cyst would probably have been missed while in the other patient images were specific and very sensitive for diagnosis of interapophyseal synovial lesions. Treatment was surgical in both cases.