Spatiotemporal source analysis in scalp EEG vs. intracerebral EEG and SPECT: a case study in a 2-year-old child.

OBJECTIVE: This case study aims to demonstrate that spatiotemporal spike discrimination and source analysis are effective to monitor the development of sources of epileptic activity in time and space. Therefore, they can provide clinically useful information allowing a better understanding of the pathophysiology of individual seizures with time- and space-resolved characteristics of successive epileptic states, including interictal, preictal, postictal, and ictal states. METHODS: High spatial resolution scalp EEGs (HR-EEG) were acquired from a 2-year-old girl with refractory central epilepsy and single-focus seizures as confirmed by intracerebral EEG recordings and ictal single-photon emission computed tomography (SPECT). Evaluation of HR-EEG consists of the following three global steps: (1) creation of the initial head model, (2) automatic spike and seizure detection, and finally (3) source localization. During the source localization phase, epileptic states are determined to allow state-based spike detection and localization of underlying sources for each spike. In a final cluster analysis, localization results are integrated to determine the possible sources of epileptic activity. The results were compared with the cerebral locations identified by intracerebral EEG recordings and SPECT. RESULTS: The results obtained with this approach were concordant with those of MRI, SPECT and distribution of intracerebral potentials. Dipole cluster centres found for spikes in interictal, preictal, ictal and postictal states were situated an average of 6.3mm from the intracerebral contacts with the highest voltage. Both amplitude and shape of spikes change between states. Dispersion of the dipoles was higher in the preictal state than in the postictal state. Two clusters of spikes were identified. The centres of these clusters changed position periodically during the various epileptic states. CONCLUSION: High-resolution surface EEG evaluated by an advanced algorithmic approach can be used to investigate the spatiotemporal characteristics of sources located in the epileptic focus. The results were validated by standard methods, ensuring good spatial resolution by MRI and SPECT and optimal temporal resolution by intracerebral EEG. Surface EEG can be used to identify different spike clusters and sources of the successive epileptic states. The method that was used in this study will provide physicians with a better understanding of the pathophysiological characteristics of epileptic activities. In particular, this method may be useful for more effective positioning of implantable intracerebral electrodes.

[Diagnosis and current concepts of management of advanced abdominal pregnancy]. / Diagnostic et concepts actuels de prise en charge de la grossesse abdominale avancée.

Authors report a case of abdominal pregnancy diagnosed by MRI at 17 SA with prospective follow-up and planned delivery at 37 SA. The diagnosis is clinically suspected when extra-uterine pregnancy risk factors or history of uterine trauma are present. This is confirmed by MRI, which may be considered as the gold standard. A conservative management may be proposed when the diagnosis is made after 20 weeks and under the following conditions: absence of fetal growth malformation, placental implantation remote from the upper abdomen, good maternal condition, close management in a hospital setting of the patient previously informed of the risks and outcomes. Placental location on the uterus seems to be a major positive factor of outcome for these pregnancies. Materno-fetal follow-up is based on physical examination, repeated ultrasonic investigations with Doppler imaging and daily fetal heart rate monitoring. In the absence of complications, a laparotomy should be planned at 34 weeks. The placenta may not be removed when a serious risk of hemorrhage is feared.

MRI texture analysis on texture test objects, normal brain and intracranial tumors.

Texture analysis was performed in three different MRI units on T1 and T2-weighted MR images from 10 healthy volunteers and 63 patients with histologically confirmed intracranial tumors. The goal of this study was a multicenter evaluation of the usefulness of this quantitative approach for the characterization of healthy and pathologic human brain tissues (white matter, gray matter, cerebrospinal fluid, tumors and edema). Each selected brain region of interest was characterized with both its mean gray level values and several texture parameters. Multivariate statistical analyses were then applied in order to discriminate each brain tissue type represented by its own set of texture parameters. Texture analysis was previously performed on test objects to evaluate the method dependence on acquisition parameters and consequently the interest of a multicenter evaluation. Even obtained on different sites with their own acquisition routine protocol, MR brain images contain textural features that can reveal discriminant factors for tissue classification and image segmentation. It can also offer additional information in case of undetermined diagnosis or to develop a more accurate tumor grading.

The dural crossing of the vertebral artery.

The aim of this study was to present the anatomic and macroscopic aspects of the vertebral artery at the level of the dural crossing. Twenty vertebral arteries in 10 cadavers were dissected. The preparations were photographed and all the samples at the level of the dural crossing were submitted to a histologic study. Macroscopic results allow specification of the relationships between the dural crossing of the vertebral artery and the nervous elements (C1 and C2 nerves, mixed nerves), the vascular elements (postero-inferior cerebellar artery), the dural sheath and the first two dentate ligament tips. Microscopic results show the intricate relationship of the different layers of the vertebral artery with the dura at its crossing. Dural fibers reinforce the adventitial fibers not only by continuing them in their contact, much as the pages of a book, but also by being encrusted into the adventitia up to the tunica media, thus creating a very efficient mooring system. This work provides some information for an understanding of the symptoms induced by foramen magnum meningiomas and the onset of clinical signs after the surgical excision of these tumors. It also explains why dissections of the suboccipital segment of the vertebral artery stop at the level of the dural crossing, and never spread towards the intracranial segment.

[Imaging of tumors of the third ventricle]. / Imagerie des tumeurs du troisième ventricule.

MR imaging now appears as the best tool for diagnosis and pre-therapeutic assessment of tumors arising in the third ventricle (V3), as MR images can be obtained in the axial, coronal, and sagittal planes. MRI makes certain the location of the tumor in the V3 and delineates the anatomical landmarks in order to plan the surgical approach. It also allows the evaluation of associated hydrocephalus. Colloid cysts, choroid plexus papillomas, cavernomas, subependymal giant cell astrocytomas and germ-cell tumors may exhibit specific radiological features.

Spontaneous portal venous gas in a patient with Crohn's ileocolitis.

In a 70-year-old man with Crohn's ileocolitis who presented with a sudden fever, ultrasound and computed tomographic (CT) examinations showed hepatic portal venous gas (HPVG). Abdominal plain film was normal. The course was benign with medical management. The authors review previous cases of portal vein gas in intestinal inflammatory diseases.

[Multiple duodenal lipomas. A x-ray computed tomographic diagnosis]. / Lipomes duodénaux multiples. Un diagnostic scanographique.

In a 65-year-old man, upper endoscopy revealed several polypoid lesions into the duodenum, for which histologic examination of the biopsy specimens showed normal mucosa. CT studies demonstrated homogeneous fat density of these nodules, and thus were diagnostic of duodenal lipomas. The diagnosis was ultimately histologically confirmed by deeper peri-endoscopic biopsies. About this case and the some previously reported ones, the authors emphasize the interest of CT examination in this small bowel tumor.

[Carney's syndrome disclosed by hemoperitoneum]. / Syndrome de Carney révélé par un hémopéritoine.

The authors report a case of Carney's triad in a blood-group O woman who successively sustained a) at age 13, a multicentric gastric leiomyoblastoma revealed by an hemoperitoneum; b) 6 years later, a pulmonary chondroma diagnosed by chest standard roentgenogram and CT scan, associated with leiomyoblastoma recurrence and hepatic metastases; c) 10 years later, a juxta-carotid tumor of unknown (paraganglion?) origin. This patient is presently in good clinical condition, in spite of hepatic metastases known for 5 years. Based on this case and the 33 previously reported cases, the main features of this very unusual entity are analyzed.

[Cavernous lymphangioma of the liver. A report of 2 cases and review of the literature]. / Lymphangiome caverneux du foie. Etude de 2 cas et revue de la littérature.

The authors report 2 cases of hepatic lymphangioma observed in a 54-year-old woman, and in a 39-year-old man. These tumors were discovered upon ultrasound examination performed for jaundice due to viral hepatitis, and for abdominal right upper quadrant pain respectively. Computed tomography and angiography showed hypervascularized tumors. Diagnosis was established through surgical biopsy specimens. The clinical course was uneventful, during respectively the 9- and 3-year follow-up periods, respectively. From these and the 40 previously reported cases, the authors describe the different features of this unusual tumor.

"Porcelain liver" appearance due to Glisson's capsule phleboliths.

A case of multiple Glisson's capsule phleboliths is reported in a 29-year-old-woman who had portal vein obstruction with spontaneous shunting resulting in hepatic siderosis and cirrhosis. The phleboliths were visible as multiple linear calcifications on plain film and computed tomography. Diagnosis was established by surgical liver biopsy. The potential mechanisms of this unique entity is discussed.

[Cecal hernia through Winslow's foramen. Radiographic study of a case and review of the literature]. / Hernie caecale par l'hiatus de Winslow. Etude radiographique d'un cas et revue de la littérature.

A case of herniation of the cecum through the foramen of Winslow is reported in a 49-year-old man, admitted for acute abdominal pain. Diagnosis, suspected by abdominal plain films, and established by water-soluble enema, was confirmed by emergency surgical management. Herniation through Winslow's foramen represents the least common variety of internal hernias. Only 136 observations were previously reported, the cecum being involved in 25-30% of cases. Radiological diagnosis was made in only one patient out of ten. Although rare in occurrence, it carries a high mortality risk when diagnosis and treatment are delayed. A better appreciation of the classic radiological features will allow for earlier recognition and treatment. Therefore, the authors emphasize the interest of radiologic findings in this condition.