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Biomedical subjects

L A Hayman

Publications and source records attributed to L A Hayman.

12 recordsLinked to original sources
PubMed1979

Scalp markers for precise craniotomy siting, using computed tomography.

A rapid, simple, and inexpensive computed tomographic technique has been developed for marking the scalp and lateral skull radiograph of patients with small cerebral convexity lesions. The more precise localization provided thereby facilitates planning and performance of surgery.

Craniotomy↗
PubMed1979

Cerebellopontine angle tumor: diagnosis by oblique projection vertebral angiography.

Oblique projection vertebral angiography is the simplest and most accurate angiographic method of detecting small cerebellopontine angle tumors. The vascular blood supply to the tumor and brainstem is displayed as the surgeon will encounter it during lateral suboccipital craniotomy. The procedure is comfortable for the patient, technically easy to perform, and reproducible. Interpretation is relatively unaffected by variations in vascular anatomy or superimposed vessel or bone images. This method can be used to supplement routine views, or be performed alone with stereoscopic filming.

Brain Neoplasms↗
PubMed1979

Rapid high dose (RHD) contrast computed tomography of perisellar vessels.

The diagnostic accuracy of CT scanning in the sellar area can be improved by using a rapid high dose (RHD) contrast technique which visualizes the supraclinoid carotid arteries, cavernous sinus and vascular plexus of the infundibulum. The RHD technique is briefly described and the pertinent anatomy discussed and illustrated.

Adenoma↗
PubMed1979

Rapid-high-dose contrast computed tomography of isodense subdural hematoma and cerebral swelling.

Ten patients were studied in whom precontrast computed tomography (CT) revealed an isodense mass which obliterated cerebral sulci and deformed the ventricle(s). Upon rapid-high-dose (RHD) contrast enhancement, the cerebral hemispheric surface was so well demonstrated, that in 4 patients the possibility of an isodense subdural hematoma was exluded, while in the other 6 it was correctly diagnosed. Preoperative angiography was not necessary.

Adult↗
PubMed1979

Choroid plexus of the fourth ventricle: a useful CT landmark.

The choroid plexus of the fourth ventricle is a sensitive, symmetrical CT landmark which can often be visualized in overlapped scans performed in the orbital plane during rapid infusion of a high dose of iodinated contrast substance. Normal and pertinent abnormal plexus configurations are described and illustrated.

Brain Diseases↗
PubMedDate not supplied

Temperature monitoring during MR imaging: comparison of fluoroptic and standard thermistors.

Temperature readings from standard wire lead thermistor probes and a fluoroptic temperature probe were compared before, during, and after exposure to a spin-echo imaging sequence at 2.35 T. All the probes were placed in saline-filled vials (1-mL capacity) surrounded by dense foam rubber to isolate and preserve local heating effects. There were no consistent differences in the temperatures recorded by the various probes. The authors conclude that wire lead thermistor probes do not exhibit substantial heat deposition when exposed to a standard spin-echo imaging sequence at 2.35 T.

Magnetic Resonance Imaging↗
PubMedDate not supplied

Change in red blood cell relaxation with hydration: application to MR imaging of hemorrhage.

T1 and T2 were measured in unclotted blood samples with 0.24- and 4.7-T spectrometers. The fraction by weight of intracellular water in the red blood cells (RBCs) was varied by either osmotic manipulation or density separation in concentrated (packed RBCs) and dilute (RBCs suspended in buffer or serum) samples. Reducing the cell water content caused a moderate decrease in T1 and a profound decrease in T2 at both 0.24 and 4.7 T. Conversely, increasing the cell water content caused an increase in both T1 and T2. The authors conclude that dehydrated RBCs in an area of hemorrhage would cause a substantial decrease in signal intensity on long TR/TE (T2-weighted) images. Overhydration of RBCs would have the opposite effect.

Adult↗