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Biomedical subjects

A L Weber

Publications and source records attributed to A L Weber.

At least 37 records · Page 2Linked to original sources
PubMed1996

Paraorbital lesions.

Explore the source record for details and available documents.

Central Nervous System Neoplasms↗
PubMed1996

Graves' disease of the orbit.

Graves' disease, the most common orbital disorder, affects approximately 0.5 % of the population of the United States. It is the underlying cause in 15% to 28% of cases of unilateral exophthalmos and in 80% of cases with bilateral exophthalmos. Also called "thyroid-associated ophthalmopathy", autoimmune thyroid disease," "endocrine exophthalmos," and "thyroid eye disease", Graves' disease presents with enlargement of the extraocular muscles, increased orbital fat volume, and venous stasis caused by increased orbital pressure. This article discusses the clinical evaluation and radiologic findings of this common orbital disorder.

Diagnosis, Differential↗
PubMed1996

Pseudotumor of the orbit.

Pseudotumor of the third most common ophthalmologic disease after Graves' disease and lymphoproliferative disease. It is usually a continuous illness, although recurrent forms do occur, especially in the pediatric age group. The radiologic evaluation consists of computed tomography and magnetic resonance imaging. The imaging findings, correlated with the clinical findings, allow a diagnosis in most cases and, hence, obviate the need for a biopsy.

Biopsy↗
PubMed1996

Lymphoproliferative disease of the orbit.

Lymphoproliferative disease of the orbit represents a diverse group of lesions affecting various soft tissue structures within the orbital cavity. They are one of the most common disease entities encountered in orbital pathology and frequently present with proptosis or anterior tumefactive swelling in the lids, conjunctiva, and lacrimal glands. For elucidation of the underlying cause, computed tomography and magnetic resonance imaging are the optimal imaging modalities.

Humans↗
PubMed1996

Benign and malignant tumors of the orbital cavity including the lacrimal gland.

CT and MR imaging are the modalities of choice in the assessment of orbital neoplasia. When combined with the clinical history and examination, radiologic imaging can provide valuable information regarding tumor diagnosis. Imaging studies thus enable the clinician to delineate the extent of disease and plan the surgical approach for biopsy or excision. In some cases, serial orbital imaging is used to monitor for tumor growth or recurrence.

Adolescent↗
PubMed1996

Imaging evaluation of the optic nerve and visual pathway including cranial nerves affecting the visual pathway.

The radiologic investigation of the optic pathways has an integral part in the diagnostic evaluation of diverse lesions, such as inflammatory disease, vascular disorders, and benign and malignant tumors that afflict the optic pathways. These radiologic methods consist principally of computed tomography and magnetic resonance imaging, and, in vascular lesions, magnetic resonance angiography and conventional angiography.

Cranial Nerve Neoplasms↗
PubMed1996

Normal anatomy and lesions of the lacrimal sac and duct: evaluated by dacryocystography, computed tomography, and MR imaging.

Diseases of the lacrimal system are optimally evaluated by dacryocystography, CT, MR imaging, and nuclear scintigraphy. Dacryocystography is selected to define the lumen of the lacrimal drainage system in inflammatory disease (dacryocystitis), dacryoceles, dacryoliths, and developmental abnormalities. Dacryocystography provides supplemental information in benign and malignant tumors, principally to differentiate an intrinsic lesion from an extrinsic lesion. CT is indicated for delineation of palpable mass lesions such as cysts, benign and malignant tumors, and diseases, especially in the paranasal sinuses, affecting the lacrimal apparatus secondarily. MR imaging has limited application but is useful to differentiate fluid from solid masses within the sac and to define tumor extension from the sac into the duct and anatomic regions outside the sac and duct. MR imaging with gadolinium enhancement should be used in suspected tumors and to separate a cyst from a solid mass. Radiologic methods fail to identify the histopathology of benign and malignant tumors. Nuclear scintigraphy is helpful in patients with epiphora with no demonstrable anatomic abnormality on dacryocystography.

Diagnosis, Differential↗
PubMed1996

Radiologic evaluation of the trachea.

Tracheal lesions are categorized into stenoses of various etiologies, inflammatory lesions, benign and malignant tumors, vascular anomalies affecting the trachea, and miscellaneous conditions including amyloid, polychondritis, and tracheobronchopathia osteochondroplastica. For evaluation of the extent and characterization of these lesions, different radiologic modalities can be utilized, which include fluoroscopy with barium swallow, conventional films, linear tomography, computerized tomography scan, and magnetic resonance imaging, including magnetic resonance angiography. The radiologic indications and findings are described in this article.

Fluoroscopy↗
PubMed1995

Prebiotic polymerization: oxidative polymerization of 2,3-dimercapto-1-propanol on the surface of iron(III) hydroxide oxide.

The oxidation of 2,3-dimercapto-1-propanol by ferric ions on the surface of iron(III) hydroxide oxide (Fe(OH)O) yielded polydisulfide oligomers. This polymerization occurred readily at low dithiol concentration under mild aqueous conditions. Polydisulfide polymers up to the 15-mer were synthesized from 1 mM dithiol in 5 ml water reacted with iron(III) hydroxide oxide (20 mg, 160 micromoles Fe) for 3 days under anaerobic conditions at 40 degrees C and pH 4. About 91% of the dithiol was converted to short soluble oligomers and 9% to insoluble larger oligomers that were isolated with the Fe(OH)O phase. Reactions carried out at the same ratio of dithiol to Fe(OH)O but at higher dithiol concentrations gave higher yields of the larger insoluble oligomers. The relationship of these results to prebiotic polymer synthesis is discussed.

Dimercaprol↗
PubMed1995

Lateral sinus thrombosis associated with otitis media and mastoiditis in children.

Lateral sinus thrombosis (LST) is an infrequent complication of otitis media and mastoiditis in the antibiotic era. A recent case of LST in a 7-year-old boy, the third such case at our institutions in the past 5 years, prompted a review of the modern day English literature concerning LST in pediatric patients. Our goal was to highlight the clinical findings suggestive of LST in the antibiotic era as well as to analyze retrospectively the diagnostic and therapeutic modalities of greatest benefit based on the outcomes reported in the reviewed studies.

Anti-Bacterial Agents↗
PubMed1995

Cartilaginous tumors and chordomas of the cranial base.

Chordomas and chondrosarcomas are uncommon skull base tumors. They are locally aggressive. Chordomas arise from the clivus with the epicenter in the midline of the skull base. Chondrosarcomas, in contrast, usually arise along the petro-occipital fissure; occasionally, a chondrosarcoma may reveal a midline location and then cannot be differentiated from chordoma. Chordomas rarely calcify, whereas calcification is not an uncommon finding in chondrosarcomas. Following radiation, calcifications also increase in area and diameter in both chondrosarcomas. Both chondrosarcomas and chordomas reveal a low signal intensity on T1-weighted MR images and medium to increased signal intensity on T2-weighted images. They commonly enhance significantly but heterogeneously, because of the presence of necrosis, calcification, and mucinous materials. Occasionally, chondrosarcomas and chordomas reveal a low degree if enhancement. The prognoses of chordomas and chondrosarcomas vary. Long-term survival is usually seen with chondrosarcomas but is still considerably compromised with chordomas.

Chondrosarcoma↗
PubMed1994

Comparison of computed tomography and surgical findings in deep neck infections.

Computed tomography is routinely used in the evaluation of patients suspected to have deep neck infections. This 10-year retrospective study compares preoperative computed tomography scan reports with intraoperative findings in 38 patients who underwent surgical exploration of the parapharyngeal or retropharyngeal space within 48 hours of their radiographic assessment. Overall, intraoperative findings confirmed computed tomography scan interpretation in 76.3% of the patients. The false-positive rate was 13.2%, and the false-negative rate was 10.5%. The sensitivity of computed tomography scan for detection of parapharyngeal space or retropharyngeal space abscess was 87.9%. This study's documentation of false-positive computed tomography scans in the evaluation of deep neck infections emphasizes the importance of correlating radiologic interpretation with clinical examination before surgical intervention.

Adolescent↗
PubMed1994

Imaging of lymphoma manifestations in the extracranial head and neck region.

CT and MRI are the most efficient imaging techniques for diagnosing lymphomas while Gallium-67 scintigraphy is used to assess treatment results. In this review, the imaging aspects of lymphoma are addressed according to anatomical subregions, from the orbit to the trachea, Waldeyer's ring being the most common site, in the head and neck. Lymphomas of this region are not easily distinguished from the more common squamous cell carcinomas; however, multiple extranodal sites, the presence of many non-necrotic lymph nodes and a large nasopharyngeal mass without significant bone destruction should alert one to the possibility of lymphoma.

Gallium Radioisotopes↗