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Biomedical subjects

T Ehsan

Publications and source records attributed to T Ehsan.

8 recordsLinked to original sources
PubMed1999

Orthostatic-mediated hypoperfusion in limb-shaking transient ischemic attack.

In patients with severe carotid stenosis or total occlusion, episodic contralateral motor dysfunction is more likely related to cerebral hypoperfusion than epileptogenic activity. A man with orthostatic-mediated right-sided limb shaking was found to have total left internal carotid artery occlusion. There was prominent reduction of cerebrovascular reserve seen on single photon emission computed tomography (SPECT) performed with and without acetazolomide. During assumption of an upright position transcranial Doppler (TCD) revealed a marked attenuation of the left middle cerebral artery flow pattern not associated with changes during electroencephalographic monitoring, even after administration of acetazolomide. In this man, limb shaking episodes were attributed to hypoperfusion of the contralateral cerebral hemisphere, and not to epileptogenic activity.

Carotid Stenosis↗
PubMed1998

Bilateral temporal hypometabolism in epilepsy.

PURPOSE: Positron emission tomography (PET) has proven useful in epilepsy surgery for its ability to identify unilateral temporal hypometabolism (UTH), which is predictive of good surgical outcome. The significance of bilateral temporal hypometabolism (BTH) is not known. METHODS: We identified all patients who had marked bilateral reduction in temporal lobe metabolism relative to the cerebellar hemispheres and compared their clinical features and treatment outcomes with those of control patients with UTH. RESULTS: BTH was evident in 10% of PET scans for epilepsy at our institution. We compared these patients with age-matched controls with UTH. The BTH patients had a higher percentage of generalized seizures; were more likely to have bilateral, diffuse or extratemporal seizure onsets; and had bilateral or diffuse magnetic resonance imaging (MRI) findings. UTH patients were more likely to have unilateral mesial temporal atrophy on MRI. Even when electrical seizure onsets were well localized, surgical outcomes were markedly worse in these patients than in controls. Medical treatment was also less successful. Social and cognitive functioning was worse in the BTH group. The only death occurred in the group with BTH. CONCLUSIONS: Patients with BTH have features distinct from those with UTH and have a worse prognosis for seizure remission after surgery.

Adolescent↗
PubMed1996

Titanium aneurysm clips: Part II--Seizure and electroencephalographic studies in implanted rabbits.

Because titanium is widely used in neurosurgical procedures, we compared spontaneous and induced epileptiform activity in 12 rabbits with titanium clips implanted in the subarachnoid space with 12 rabbits with cobalt alloy clips and 6 rabbits that were not operated on that served as controls. Beginning 1 week after surgery, 30-minute electroencephalographic recordings were made at monthly intervals for 6 months. Recordings were scored by an electroencephalographer unaware of which treatment group was being recorded. In 48 recordings made during 6 months, no epileptiform activity was observed in any animal. Seizure threshold was evaluated by continuous intravenous injection of the convulsant drug, pentylenetetrazole (2 mg/kg/min), with continuous electroencephalographic recording. Time to spiking for the nonsurgical control group was 327 mean seconds +/- 181 standard deviation (SD), 216 mean seconds +/- 135 SD for the titanium group, and 389 mean seconds +/- 290 SD for the cobalt group. There were no significant differences among the groups (P = 0.17). Latency to behavioral tonicoclonic seizure was 1031 seconds +/- 537 SD for the group not operated on, 875 seconds +/- 334 SD for the titanium group, and 1267 seconds +/- 764 SD for the cobalt group. This study suggests that titanium clips are well tolerated within the brain and will not induce seizures.

Animals↗
PubMed1996

Epidural hematoma producing Brown-Séquard syndrome: a case due to ruptured hemangioma with magnetic resonance imaging findings.

A man developed spontaneous spinal epidural hematoma secondary to ruptured hemangioma with a clinical picture resembling acute partial Brown-Séquard syndrome. Diagnosis by magnetic resonance imaging (MRI) allowed prompt surgical decompression and complete reversal of the neurological deficits. The diagnosis, etiology, and MRI findings of spinal epidural hematomas are discussed.

Adult↗
PubMed1995

Magnetic resonance evidence of perineural metastasis.

Contiguous spread along perineural and endoneural spaces, that is, perineural tumor extension, in cutaneous squamous cell carcinoma is fairly common. Infrequently, these tumors spread and involve intracranial structures. One consequence of this complication is meningeal carcinomatosis which is underrecognized. Herein described is a patient with recurrent cutaneous squamous cell carcinoma with perineural invasion along the maxillary nerve that was subsequently shown by magnetic resonance imaging to the trigeminal root. The patient initially presented with a cavernous sinus syndrome but despite aggressive treatment, extensive meningeal carcinomatosis and cauda equina dysfunction developed. Awareness of perineural invasion and proper evaluation are crucial. Perineural spread intracranially worsens the prognosis and limits treatment options to palliation.

Aged↗
PubMed1995

Serial magnetic resonance imaging in isolated angiitis of the central nervous system.

Isolated angiitis of the central nervous system (IACNS) is a rare form of vasculitis restricted to the CNS. We report serial MRI findings in a biopsy-proven case of IACNS. MRI showed extensive white matter and subcortical disease. Before specific treatment, neuroimaging showed the development of new lesions corresponding with an overall progressive clinical course of the illness; the post-treatment MRI showed improvement.

Brain↗
PubMed1994

Hyperdense basilar artery. An early computed tomography sign of thrombosis.

Noncontrast computed tomographic scans (CT scans) may show a hyperdense basilar artery before a brainstem infarct is visualized. This early sign should assist clinicians in confirming the diagnosis of basilar artery thrombosis. In a review of admission records of 750 patients with acute cerebrovascular disease from July 1991 to June 1993, at Saint Louis University Hospital, 20 patients were identified with clinical signs of nonlacunar, vertebrobasilar distribution infarction. Eight of these had pontomesencephalic ischemia. Their neuroimaging studies and medical records were evaluated. Four patients with acute clinical signs of pontomesencephalic infarction were found to have a hyperdense basilar artery on CT scans. The scans of 2 patients were excluded because of dolichoectasia; in the other 2 patients, the basilar artery appeared normal on the CT scan. The hyperdense basilar artery was detected within the early hours of neurological symptoms and often was the only detectable abnormality on the scan. In 3 patients extensive brainstem infarcts subsequently developed and they died. Basilar artery thrombosis was confirmed by pathological study in all these patients. In the fourth patient basilar artery occlusion and a large pontine infarct were evident by magnetic resonance imaging and angiography. A hyperdense basilar artery is a common feature on CT scans of patients presenting with an early clinical diagnosis of thrombosis. Untreated, the hyperintense basilar artery often portends a poor prognosis. Its ready recognition should guide further interventional studies and treatment.

Adult↗