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J M Taveras

Publications and source records attributed to J M Taveras.

At least 91 records · Page 5Linked to original sources
PubMed1966

Thalamic tumors.

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Adolescent↗
PubMedDate not supplied

Exercise-related dissection of craniocervical arteries: CT, MR, and angiographic findings.

OBJECTIVE: Our goal was to demonstrate the spectrum of neuroradiologic (CT, MR, and angiographic) findings in craniocervical arterial dissection (CAD) related to exercise or sporting activities and compare the diagnostic utility of CT, MRI, and MR angiography (MRA). MATERIALS AND METHODS: The neuroradiologic examinations of 11 patients with CAD was performed: CT was performed in 10 patients, cranial MRI in 9, cranial and cervical MRA in 4, and contrast angiography in 10. The CT examinations were assessed for the presence of an infarction or a hyperdense artery (consistent with intraluminal thrombus), MRI examinations for the presence of infarction or abnormal periarterial signal, and contrast angiograms for arterial stenosis or occlusion, luminal irregularity, pseudoaneurysm, intimal flap, or distal branch occlusions. RESULTS: Computed tomography demonstrated infarction in four patients. At contrast angiography, a dissection was found in the artery supplying the region of infarction in all cases. A hyperdense artery was found by CT in two patients, which correlated with dissection of the artery or its parent artery on contrast angiography. Cranial MRI findings were seen in six patients (infarction in five, periarterial signal abnormality in five). Dissection was confirmed in all four patients with abnormal periarterial signal who underwent contrast angiography. Two patients with abnormal intracranial periarterial signal had corresponding abnormalities on MRA. False-negative cranial and cervical MRI and MRA studies were performed in one patient because the imaging volumes used for the cervical and intracranial MR examinations did not overlap. Four patients with normal intracranial arterial signal had dissection in the neck demonstrated by contrast angiography. CONCLUSION: Neuroradiologic findings of CAD can include infarction, a hyperdense artery on CT, abnormal periarterial signal on MRI, and a narrowed arterial signal column on MRA. Computed tomography is an insensitive screening examination. Proper use of MRI and MRA involves examination of both the head and the neck with overlapping imaging volumes of the two regions.

Adolescent↗
PubMedDate not supplied

Positron imaging of cerebral blood flow during continuous inhalation of C15O2.

This investigation tests the hypothesis that the normal cerebral image obtained non-invasively during continuous inhalation of C15O2 is related to cerebral blood flow. Trace amounts of CO2 labeled with the positron-emitting radionuclide 15O were administered to 4 normal subjects at normo- and hypocapnia and to 2 of these subjects at hypercapnia. Hypocapnia typically caused a marked decrease in cerebral 15O activity, and hypercapnia a small increase in activity. The relative difference in the change in count rate in response to hypo- and hypercapnia is what one would expect if the activity represented bloow flow, according to a mathematical model which assumes the 15O label enters the brain as water of perfusion. The findings in this study suggest that the normal cerebral image obtained during continuous inhalation of C15O2 is related to cerebral blood flow, but in a non-linear fashion, and that the technique would be more sensitive to ischemic events than to hyperemic phenomena.

Adult↗