PubMed · 7138372
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N R Olson. 1982. Frontal sinus ablation.. https://doi.org/10.1001/archotol.1982.00790590071019
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Diffusion weighted MRI offers the possibility to study the course of the cerebral white matter tracts. In the present manuscript, the basics, the technique and the limitations of diffusion tensor imaging and anisotropic diffusion weighted MRI are presented and their applications in various neurological and neurosurgical diseases are discussed with special emphasis on the visual system. A special focus is laid on the combination of fiber tract imaging, anatomical imaging and functional MRI for presurgical planning and intraoperative neuronavigation of lesions near the visual system.
To date functional magnetic resonance imaging (fMRI) has not been extensively used in presurgical evaluation of patients with intractable epilepsy. Patient S.P. presented with left frontal originating seizures, secondary to a large porencephalic cyst that encompassed much of his occipital and temporal cortex and a substantial portion of ipsilateral parietal cortex. Nevertheless, S.P. did not demonstrate any gross impairments of praxis or speech. Scalp electroencephalogram (EEG) telemetry revealed reduced background activity in the left hemisphere, an absence of identifiable normal sleep states, and confirmed the left frontal origin of his seizures with a prolonged postictal state, suggesting that the remaining cortex in S.P.'s left hemisphere did not function normally despite his apparently normal appearance. Dichotic listening results also suggested that S.P. had an atypical language representation suggestive of either bilateral or right hemisphere speech representation. Surgical intervention to remove the remaining left hemisphere cortex was a serious consideration for treatment of S.P.'s seizures. We used fMRI to evaluate whether or not the remaining cortex in S.P.'s left hemisphere supported any cognitive or motor functions. Even though the volume of cerebral cortex was severely reduced and displaced in the left hemisphere, fMRI revealed significant activation in this remaining tissue in response to motor, somatosensory, and word generation tasks. In other words, we were able to demonstrate using fMRI that the remaining tissue in S.P.'s left hemisphere continued to support some motor and cognitive functions. The possible implications of these findings in terms of functional reorganisation are discussed briefly.
The aim of this study was to determine the spectrum of clinical abnormalities in the agyria-pachygyria complex, to identify possible causes, and to correlate the clinical features with the extent of the lesions on magnetic resonance imaging. On the basis of the magnetic resonance imaging findings, 37 patients (22 males, 15 females; mean age 21.1 +/- 31.2 months) with agyria-pachygyria complex were separated into two groups: Group 1 (18 children) manifested generalized or bilateral gyral malformation, and Group 2 (19 children) manifested localized or unilateral gyral malformation. The ratio of generalized seizures in Group 1 was significantly higher, whereas partial seizures were more common in Group 2. Group 1 patients had seizures significantly more frequently than Group 2 patients. Diffuse electroencephalographic abnormalities were significantly more common in Group 1, as were the localized abnormalities in Group 2. Hemipareses were the most frequent neurologic deficit among Group 2 patients. Spastic quadriparesis and microcephaly were more common in Group 1. In conclusion, the extent of agyria-pachygyria complex varies widely and the clinical features are accordingly diverse. Patients with bilateral or generalized gyral anomalies have poor prognosis for outcome of epilepsy and neurologic disability. The recognition of these lesions with higher-resolution techniques of magnetic resonance imaging is important for planning proper treatment and genetic counseling.