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Biomedical subjects

B Guillon

Publications and source records attributed to B Guillon.

28 records · Page 2Linked to original sources
PubMed1998

Correlation between interictal regional cerebral blood flow and depth-recorded interictal spiking in temporal lobe epilepsy.

PURPOSE: Single photon emission computed tomography (SPECT) is used as an adjunctive method in preoperative localization of epileptic foci. In temporal lobe epilepsy (TLE), interictal hypoperfusion is observed in 60-70% of cases. Correlation with ictal EEG changes is observed in approximately 50-60% of cases. Relationships with interictal EEG have been studied less. We compared interictal SPECT data obtained in 20 patients with their interictal intracerebral electrical activity recorded by depth electrodes to evaluate a potential relationship. METHODS: We studied 20 sequential patients whose clinical, surface, and depth EEG data indicated seizure originating in the temporal lobe and who had interictal [99mTc]hexamethylpropylene amine oxime (HMPAO)-SPECT stereo-EEG (SEEG). Intracerebral electrodes were placed according to the patient's profile. The interictal extent of epileptiform activity allowed delineation of the irritative zone. Interictal spike frequency was also analyzed semiquantitatively. Visual and numerical SPECT analysis was performed blind to SEEG data. RESULTS: Interictal hypoperfusion was observed in 16 patients, involving the epileptogenic temporal lobe in 14. Except for 1 patient who manifested lateral temporal hypoperfusion corresponding to a mass lesion, two distinctive patterns of hypoperfusion were noted: (a) mesial hypoperfusion (5 patients), and (b) global temporal hypoperfusion (8 patients). In 8 patients, hypoperfusion had also extended into the adjacent cortex. Temporal mesial hypoperfusion was associated with spiking limited to the mesial structures, whereas global temporal hypoperfusion or hypoperfusion extending beyond the temporal lobe was associated with a similar topographic pattern of spikes. CONCLUSIONS: Comparison between SPECT and SEEG data collected in the interictal phase indicated that the extent of the hypoperfused area correlated topographically with that of the underlying irritative zone.

Adolescent↗
PubMed1998

[Current imaging of an "aberrant course" of the internal carotid artery].

Blood flow via an aberrant internal carotid artery within the tympanic cavity is a rare pathogenic embryonic variation causing pulsatile tintinus and a vascularized tympanum. CT-scan provides the diagnosis. MRI and 3D time-of-flight MRA appear ideal for exploring aberrant flow both for diagnostic purposes and to establish the vascular morphology.

Adolescent↗
PubMed1997

[Direct carotid-cavernous fistula. Clinical, radiologic and therapeutic studies. Apropos of 49 cases].

MATERIALS AND METHODS: From 1977 to 1996, 49 direct carotido-cavernous fistulae were studied among the sixty some cases diagnosed over these 20 years. Five were caused by spontaneous rupture of an intracavernous aneurysm and the others were caused by trauma. RESULTS: The clinical presentation in 37 patients was exophthalmia with pulsating conjunctival hyperhemia and vascular murmur. Some cases had a neurological syndrome suggesting cavernous involvement. A bilateral presentation was observed in 2 cases. One patient had no ophthalmologic syndrome but had a vascular murmur. Prior to 1982, all patients were treated and cured by occlusion of the internal carotid after direct access via the neck using a 3 F Fogarty catheter. Since 1982, patients have been treated with the detachable balloon technique. The carotid was preserved in 16 cases. In one case, secondary thrombosis occurred due to major dissection. In one case, the size of the breach was too small for the balloon so a coil was used. In one other case, insertion of the guide wire and catheter was sufficient to occlude the fistula. There was one death during treatment due to fistula rupture and one partially regressive right hemiplegia which could not be explained. This patient also developed left hemiplegia two years later, again with no explaining cause. Cure was achieved in the other patients without sequellae. DISCUSSION: Direct carotido-cavernous fistulae due to rupture of an aneurysm or trauma are uncommon. When flow through the breach is minimal, vascular treatment may not be necessary unless clinical signs appear since this type of fistula heals spontaneously. In other cases, an endovascular balloon procedure is indicated. There are few complications. Embolization with coils or other devices should only be used in selected cases when the breach is too small for the balloon.

Adolescent↗
PubMed1994

Central nervous system involvement in multifocal demyelinating neuropathy with persistent conduction block.

We report the case of a 27-year-old man treated for bilateral optic neuritis 5 and 3 years before who within a few months developed sensorimotor disorders of the arms and legs characterized by asymmetric distribution and distal prominence. In addition to sensorimotor defects, which were particularly marked in the left arm and right leg, clinical examination showed nearly generalized areflexia. Electrophysiological studies revealed a multifocal neuropathy with persistent distal and proximal conduction blocks associated with a considerable slowing of motor nerve conduction, as well as central nervous system involvement indicated by motor-, somatosensory-, and visual-evoked potentials. CSF analysis showed a mildly elevated protein level; anti-GM1 activity was negative. Sural nerve biopsy revealed onion-bulb-like formations, and cerebral MRI showed a small, isolated, and aspecific high signal for white matter. First described by Lewis and Sumner in 1982, multifocal neuropathy with persistent conduction blocks may be associated with central demyelination. Our case is compared with 3 similar ones in the literature, and the favorable effects of steroid therapy are emphasized.

Adult↗
PubMed1985

Tomographic measurement of cerebral blood flow by the 68Ga-labelled-microsphere and continuous-C15O2-inhalation methods.

The measurement of cerebral blood flow (CBF) by continuous C15O2 inhalation has only been validated previously by indirect experimental protocols. In the present study using baboons, these measurements were compared directly with those obtained by injection of 68Ga-labelled serum-albumin microspheres in the left cardiac ventricle. Using a modified labelling technique, no elution of 68 Ga occurred in vivo. Both methods provided similar regional CBF values, which could be described by a significant linear correlation (CBFCO2 = 0.82 CBFmicrospheres + 5.7; P less than 0.001). The validity of the labelled-microsphere-injection method was verified. The feasibility of stable in vivo labelling of 68Ga to serum-albumin microspheres provides a reference method for organ blood-flow measurements using positron-emission tomography.

Animals↗