Michael Ronthal

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Rapid MRI of the molecular diffusion of water demonstrated cerebral infarcts in 32 patients. We studied these patients at various times following the onset of ischemic symptoms and found that diffusion-weighted imaging revealed the infarcts sooner than conventional T2-weighted spin-echo imaging did; four hyperacute infarcts were shown only by(More)
Dynamic contrast-enhanced T2-weighted magnetic resonance (MR) imaging and MR angiography (MRA) were used to evaluate cerebral blood volume and the intracranial arterial system in 34 patients within 48 hours after the onset of cerebral ischemia. In 24 of the patients, an abnormality identified on T2-weighted images corresponded to the acute clinical deficit.(More)
The authors assessed regional cerebral blood flow dynamics with magnetic resonance (MR) imaging enhanced with gadolinium diethylenetriaminepentaacetic acid (DTPA). After bolus administration of Gd-DTPA, rapid T2*-weighted gradient-echo images were acquired. Image acquisition time ranged from 2 to 3 seconds. The signal intensity (SI) of brain tissue and(More)
The authors report two cases of visual field defects which are postulated to be due to the distal end of an elongated basilar artery compressing the visual pathways in the posterior suprasellar region. The mechanism of production of these defects is discussed, relating the abnormal position of the distal end of the basilar artery to a normally situated or(More)
Reproductive and sexual dysfunction in men with epilepsy has been attributed to androgen deficiency. Low serum free testosterone (FT) levels occur in both hypogonadotropic and hypergonadotropic hypogonadism. Antiepileptic drugs (AEDs) have been implicated. Proposed mechanisms include induction of increased sex hormone binding globulin (SHBG) resulting in(More)
The requisite visual modalities for the reflex blink to visual threat have not been thoroughly studied. We identified five patients with different focal cerebral lesions documented on computerized tomography scan who had abnormal blink-to-threat reflexes. One had a homonymous hemianopia secondary to posterior cerebral artery occlusion; another had a(More)
We describe the appearance of left hemineglect and striking cataleptic posturing, more prominent in left-sided extremities, in a patient without psychiatric illness. Neuroimaging demonstrated a large posterior right hemisphere infarct involving the parietal, occipital, and temporal lobes, the insula, and caudate. Additional movement abnormalities that(More)