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Biomedical subjects

A G Osborn

Publications and source records attributed to A G Osborn.

At least 73 records · Page 4Linked to original sources
PubMed1978

The angiographic ocular choroidal crescent: distortion with intraorbital and remote intracranial pathology.

The ocular choroidal plexus can be identified on virtually all normal internal or common carotid angiograms. Posterior flattening of the choroid is often seen with retrobulbar tumors. This angiographic appearance can also be observed in some patients with papilledema and increased intracranial pressure. In these patients, ampulliform dilatation of the dura and subarachnoid space just posterior to the globe produces a retrobulbar mass effect that can mimic true retrobulbar tumor. Enlargement of the ocular choroid crescent is an unusual angiographic finding and can be seen with intraocular expansile lesions such as unilateral axial high myopia with posterior staphyloma. An abnormally small, shrunken choroidal blush can be seen with microphthalmia, extreme degrees of hyperopia, and in the phthisical eye.

Carotid Arteries↗
PubMed1978

Low attenuation lesions in the midline posterior fossa: differential diagnosis.

A wide variety of cystic appearing or low attenuation lesions in the midline posterior fossa can so closely resemble one another as to render specific histologic diagnosis from CT scans alone fraught with error. Absorption coefficients often overlap and are too nonspecific to infer consistently accurate histologic diagnosis. It is virtually impossible to separate cystic from noncystic, benign from malignant, and neoplastic from non-neoplastic lesions by absorption coefficients alone.

Brain↗
PubMed1978

The evaluation of ependymal and subependymal lesions by cranial computed tomography.

Lesions of the ventricular ependyma and its derivatives can be visualized by CT scans, and their nature and extent can be determined. Generalized enhancement of the ependyma following the administration of intravenous contrast media can be seen with spendymoma, medulloblastoma, metastatic dysgerminoma, glioblastoma multiforme, and ependymitis. Localized ependymal enhancement can often be identified in the presence of acute ventriculitis, vascular anomalies or malformations, cerebral infarctions with luxury perfusion, and vascular neoplasms.

Adolescent↗
PubMed1978

Direct sagittal computed tomographic scans of the face and paranasal sinuses.

Sagittal CT scans regenerated from the axial scan data have utilized multiple thin overlapping cuts to reduce noise level. Even with this technique, computer rearranged scans provide less than optimal delineation of the intracranial and facial structures. The authors obtained direct sagittal scans of the head using a special accessory table adapted for use in wide aperture whole body scanners. These positional or true sagittal scans have spatial and density resolution nearly equal to that achieved in the standard axial plane. The table configuration is described. Normal sagittal CT anatomy of the face is compared to gross anatomical sections, specimen radiographs, and plain film tomograms.

Evaluation Studies as Topic↗
PubMed1978

The nasal arteries.

Thorough knowledge of the normal gross and radiographic anatomy of the nasal fossa is a prerequisite for correct interpretation of external carotid angiograms in patients with lesions in or adjacent to the nasal cavity. This report describes in detail the normal gross and angiographic vascular anatomy of the nasal fossa. The appearance of the sphenopalatine artery and nasal branches of the ethmoidal arteries in a variety of lesions that affect the nasal cavity, nasopharynx, and adjacent structures is also discussed. Typical changes in acute rhinitis, sinusitis, sphenopalatine neuralgia, vascular malformations, neoplasms, and benign bulky nasal masses are illustrated.

Acute Disease↗
PubMed1978

Diagnosis of ascending transtentorial herniation by cranial computed tomography.

The secondary effects of large infratentorial masses may include ascending transtentorial herniation. Rostral displacement of the superior vermis through the tentorial incisura can be accurately detected by cranial computed tomography. Signs of early or impending upward herniation are compression and slight posterior flattening of the quadrigeminal plate cistern. Progressively more severe herniation produces amputation of the peritcetal cerebrospinal fluid diamond, leading to a triangle or "squared off" appearance of the confluent quadrigeminal and superior cerebellar cisterns. When the disorder is severe, the herniated vermis plugs the incisura, completely effacing these cisterns and flattening the posterior third ventricle. Obstructive hydrocephalus may also occur with moderate or severe herniation.

Aged↗
PubMed1978

The vertex scan: an important component of cranial computed tomography.

Physicians who monitor cranial computed tomography occasionally omit the most superior aspects of the brain and calvarium because of time limitations and overloaded scanning schedules. In addition, standardized CT reporting forms as well training literature distributed by some manufacturers support the concept that a complete CT series consists of three scan pairs. Omission of a vertex scan pair results in failure to visualize 10%-15% of the brain volume. We have reviewed the results of 2,000 consecutive CT studies to determine the number and variety of pathologic entities that would have been missed had a vertex scan not been obtained. The most significant or sole abnormality was present on the vertex scan alone in 3% of the cases. Examples are presented. A true vertex levels should be obtained in every routine CT examination.

Adult↗
PubMed1978

Radiology of the jugular tubercles.

The jugular tubercles are two small protuberances that arise from the inferolateral margins of the clivus and project posterosuperiorly over the hypoglossal canals. The jugular tubercles are clearly seen on routine anteroposterior temporal bone tomograms and may be identified on axial or coronat CT scans. Varying widely in size and configuration, these structures are usually somewhat ovoid but can be elongated, gently squared, or asymmetric. Despite this variation in size and appearance, no normal instances were found in which the superior surface of the jugular tubercles appeared either flattened or concave. The radiology of the normal and pathologic jugular tubercle is described. The material outlined was derived from radiographic studies of both dried skulls and a variety of normal and abnormal clinical cases.

Adult↗
PubMed1978

Intracranial air on computerized tomography.

Intracranial gas may be epidural, subdural, subarachnoid, parenchymal, or intraventricular. Intracranial air can be easily diagnosed and its location correctly assessed by computerized tomography. Potentially serious complications of intracranial air, such as tension pneumocephalus, can be rapidly and accurately identified, facilitating appropriate clinical therapy.

Adolescent↗
PubMed1977

The medial tentorium and incisura: normal and pathological anatomy.

There are large variations in the length and breadth of the tentorial incisura, its relationship to the brainstem, and in the exact course and position of the free tentorial margins. On contrast-enhanced CT scans, the obliquely sectioned posterolateral tentorial leaves of the tentorial notch can usually be delineated easily. Lesions intrinsic to the tentorial hiatus are discussed and the CT features of remote mass effects causing transtentorial herniation described.

Adult↗
PubMed1977

Diagnosis of descending transtentorial herniation by cranial computed tomography.

Descending transtentorial herniartion (DTH) secondary to a supratentorial mass effect can be detected by CT. Early signs of uncal herniation include encroachment on the suprasellar cistern, displacement of the brain stem, enlargement of the ipsilateral crural subarachnoid space, and compression of the contralateral cerebral peduncle. Increasingly severe combined uncal and hippocampal DTH results in progressive obliteration of the suprasellar and interpeduncular cisterns, elongation or compression of the brain stem, and inferior or posterior displacement of the basilar artery.

Adult↗
PubMed1977

Thin-section computed tomography in the evaluation of third ventricular colloid cysts.

The computed tomographic (CT) scan findings in 4 cases of third ventricular colloid cyst are presented, and the importance of thin-section CT in the evaluation of this lesion is discussed. Overlapping 8-mm sections are helpful in differentiating normal vasculature adjacent to the foramen of Monro from a third ventricular colloid cyst.

Cerebral Ventricles↗
PubMed1977

Efficacy of simple sedation of pediatric computed tomography.

A mixture of meperidine, chlorpromazine, and promethazine was used for sedation prior to computed tomography in pediatric patients. Diagnostic-quality scans were obtained in 88% of cases, and there were no important complications. Advantages of routine use of sedation over general anesthesia include random scheduling of adults and children, independence from the other demands placed on the anesthesia service, less need to admit these children to the hospital, and low cost.

Child, Preschool↗
PubMed1977

Fibromuscular dysplasia as a cause of stroke in infancy and childhood.

Two children had abrupt onset of hemiplegia due to childhood fibromuscular dysplasia (FMD). Although FMD is a recognized cause of strokes in adults, the disorder has not, to our knowledge, been reported previously in children. Our report reviews the pathology and diagnosis of FMD and discusses the complexities of its treatment.

Cerebrovascular Disorders↗
PubMed1975

Angiographic signs of corpus callosal tumors: a reappraisal.

Angiographic findings of eleven corpus callosal tumors are analyzed. Three new angiographic signs are demonstration of the lateral ventricular roof veins, spreading of the septal veins, and actual demonstration of corpus callosal thickening. In contrast to traditional concepts, diagnostic abnormalities were angiographically demonstrated in all eleven cases. Biplane angiotomography is of vital importance in the angiographic diagnosis of this frequently subtle tumor.

Adult↗
PubMed1967

Effects of thiopental sedation on learning and memory.

Subjects who were administered thiopental showed a loss of memory for events discussed while they were under sedation. We tested the subjects for recognition memory of pictures and recall of associated pairs of letters and words, and found that the subsequent memory loss was correlated with the concentration of thiopental in the venous blood at the time the material was learned. Retention did not appear to be state-dependent because the subject, while under sedation, could recall material learned prior to sedation, and because recall was not facilitated by reinstatement of the sedation.

Female↗