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Biomedical subjects

E A Stevens

Publications and source records attributed to E A Stevens.

9 recordsLinked to original sources
PubMed1991

Comparison of CT, low-field-strength MR imaging, and high-field-strength MR imaging. Work in progress.

To assess objectively the sensitivity and specificity of low-field-strength (0.064 T) magnetic resonance (MR) imaging, a prospective blind study of 280 examinations was performed to compare low-field-strength MR imaging with computed tomography (CT) and with high-field-strength (1.5-T) MR imaging of the cranium. The sensitivity (defined as the true-positive rate) with high-field MR imaging was superior to that with low-field MR imaging and CT in helping detect overall abnormalities. Sensitivities were generally similar over a broad range of specific cranial central nervous system diseases. Low-field and high-field MR imaging were equivalent in the blind diagnoses of neoplasms and white matter disease, whereas low-field MR and CT were equivalent in the blind diagnoses of contusion, subdural and epidural hematoma, sinus disease, normality, and abnormality. The specificities with low-field MR imaging and CT were substantially better than those with high-field MR imaging.

Brain↗
PubMed1979

Prazosin, pharmacokinetics and concentration effect.

The pharmacokinetics and effects of prazosin have been studied after intravenous and oral dosing (1 mg) to 6 normal male volunteers. The mean terminal (beta) half-life was 2.9 h after intravenous and oral routes. Oral bioavailability was 56.9%. The effects of prazosin on blood pressure were more pronounced after intravenous than oral administration, and the hypotensive effect greater on erect blood pressure. There was a significant correlation (P less than 0.02) between the fall in blood pressure and the plasma drug concentration after intravenous prazosin.

Administration, Oral↗
PubMed1979

Bilateral interhemispheric subdural hematomas.

Interhemispheric subdural hematomas are rare. Bilateral interhemispheric subdural hematomas in a patient with a ventriculoperitoneal shunt for hydrocephalus were diagnosed by computerized tomographic (CT) scan after mild head trauma. The value of CT scanning, the clinical presentation and treatment, and a review of the literature are presented.

Adult↗
PubMed1978

Quantitative aspects of contrast enhancement in cranial computed tomography.

The temporal relationship of blood iodine levels to tumor enhancement in cranial computed tomography was studied in a series of patients. Both the bolus and biphasic techniques were evaluated. Peak tumor intensity may not develop immediately, but may be more pronounced on a 20-minute scan. The low-density centers seen in malignant gliomas show delayed enhancement. These low-density centers represent a second compartment which equilibrates with the intravascular and interstitial contrast material at a much slower rate. Patients with malignant gliomas can be scanned up to one hour following contrast injection without significant loss of information.

Blood-Brain Barrier↗
PubMed1978

Computed tomographic brain scanning in intraparenchymal pyogenic abscesses.

Retrospective analysis of 25 pyogenic brain abcesses diagnosed by computed tomography (CT) revealed relatively specific morphologic characteristics of these infections. The ability to obtain an early accurate diagnosis resulted in a dramatic decrease in patient morbidity and mortality. Repeated examinations by CT permitted close monitoring of the response of the abscess to antibiotic therapy. In some instances the need for surgical intervention was eliminated or the surgical approach was modified as a result of these studies.

Actinomycosis↗