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Biomedical subjects

R A Tang

Publications and source records attributed to R A Tang.

47 records · Page 3Linked to original sources
PubMedDate not supplied

A guide to the isolated dilated pupil.

The poorly reactive and dilated pupil observed in a comatose patient is often thought to represent an acute third nerve palsy owing to brain herniation or aneurysm. In the well patient, however, the isolated dilated pupil is unlikely to be owing to a third nerve palsy. It is more commonly owing to other benign causes such as local iris sphincter abnormalities, pharmacologic dilation, tonic pupil syndrome, or sympathetic irritation. This article presents a diagnostic flowchart to help the primary care physician analyze this problem and prevent costly and unnecessary imaging of these patients.

Cranial Nerve Diseases↗
PubMedDate not supplied

Chiasmal trauma: clinical and imaging considerations.

This report presents a patient who sustained closed head injury with chiasmal trauma. This uncommon injury may not be apparent on routine imaging studies. It is significant, not only from the visual standpoint, but also because of the association with serious conditions, such as panhypopituitarism, traumatic carotid aneurysm, carotid cavernous fistulae, and meningitis associated with leakage of cerebrospinal fluid. This report demonstrates that magnetic resonance imaging (MRI) is the best method for identifying chiasmal abnormalities.

Accidents, Traffic↗
PubMedDate not supplied

A sellar misadventure--imaging considerations.

This report describes a patient with a headache and a bitemporal hemianopsia immediately following endoscopic ethmoid and sphenoid sinus surgery. Computed tomographic imaging revealed tension pneumocephalus caused by surgical interruption of the boundaries between the sinus(es) and the anterior cranial cavity. The delineation of the central chiasmal injury required follow-up magnetic resonance imaging.

Adult↗
PubMedDate not supplied

A practice pathway for the initial diagnostic evaluation of isolated sixth cranial nerve palsies.

PURPOSE: To define a practice pathway for the evaluation of sixth-nerve palsies (SNPs) and to determine its cost-effectiveness and validity in a retrospective chart review. METHODS: A Medline search of the English-language literature from 1966 to 1995 was performed to define the available clinical evidence and develop the practice pathway. The authors retrospectively reviewed 407 charts with the diagnosis of SNP seen at three centers. Information obtained included: etiologic diagnosis if known; development of new neurologic or ophthalmologic findings; and results and costs of neuroimaging studies, if performed. RESULTS: Of the 407 patients, 98 underwent computed tomography scans and 212 underwent magnetic resonance imaging of the head. Eighty cases were non-isolated, 317 were isolated SNP, and ten could not be classified from chart information. Of the 317 cases of isolated SNP, 49 were classified as traumatic; 5, congenital; 158, vasculopathic; 63, nonvasculopathic; and 42, progressive or unresolved. Following the recommendations of the practice pathway, the 158 patients classified as having vasculopathic SNP would not have undergone neuroimaging studies, realizing a savings of $100,000 in this study population of 407 patients. CONCLUSION: The recommendations of the practice pathway are supported by review of the literature and the retrospective review of these cases. However, a prospective study with a matched control group is needed to demonstrate regional and specialty-specific variations in care and to strengthen the clinical certainty of the pathway recommendations.

Abducens Nerve↗
PubMedDate not supplied

Retinal varicosity in Klippel-Trenaunay syndrome.

A retinal varicosity in the Klippel-Trenaunay syndrome is observed and diagnosed in a 24-year-old female. Fluorescein angiography was used to illustrate and specify the nature of the retinal vascular anomaly.

Adult↗
PubMedDate not supplied

See-saw nystagmus after strabismus surgery.

A 7-year-old child underwent craniotomy for a craniopharyngioma. One month later she developed a divergence excess type exotropia and had strabismus surgery 11 months later. The day after strabismus surgery, the parents noted abnormal eye movements that represented see-saw nystagmus. The patient had a small esotropia after surgery, but it was found that stimulated convergence controlled the nystagmus. This case illustrates the dual central and ocular influence on the development of see-saw nystagmus.

Child↗
PubMedDate not supplied

Pseudo oculomotor palsy as the presenting sign of linear scleroderma.

A case of linear scleroderma presenting as a pseudo oculomotor palsy is reviewed. The patient's facial skin abnormalities suggested the underlying etiology. This case illustrates a previously unreported finding in linear scleroderma, mydriasis without atrophy, reminding the clinician to look at the skin in patients with unexplained unilateral pupillary disturbances.

Biopsy↗
PubMedDate not supplied

High-resolution MR imaging of juxtasellar meningiomas with CT and angiographic correlation.

The purpose of this study was to compare the relative merits of MR imaging, CT, and angiography in the preoperative evaluation and postoperative follow-up of patients with juxtasellar meningiomas. High-resolution MR studies in nine patients with juxtasellar meningiomas were evaluated and compared with CT and angiography. The techniques were compared for the evaluation of suprasellar, parasellar, and intrasellar extension, as well as for vascular displacement or encasement, postoperative recurrence or residual calcification, and bone changes. MR provided additional information considered significant by the neurosurgeon when compared with CT, and MR was considered superior to CT in the juxtasellar area. Although MR does not obviate angiography, in many cases angiographic findings were predictable by MR.

Cerebral Angiography↗
PubMedDate not supplied

Telemedicine enters eye care: practical experience.

1. A combination of store-and-forward technology and videoconferencing technology can be used in eye care and other medical specialties. 2. Bandwidth is a rate-limiting factor for obtaining a high-resolution, real-time image. 3. Protocols, clinical and technical, must be used to implement telemedicine in an efficient and high-quality manner.

Humans↗