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Biomedical subjects

R L Dallow

Publications and source records attributed to R L Dallow.

29 records · Page 2Linked to original sources

Reliability of orbital diagnostic tests: ultrasonography, computerized tomography, and radiography.

A series of 342 patients with unilateral exophthalmos underwent orbital diagnostic studies including ultrasonography, computerized tomography, radiographic studies, and vascular contrast studies. Each test was found to have diagnostic capabilities that complemented other studies depending upon the specific disease process involved. No one test was entirely adequate without supplementary information from the other tests. Radiographic studies demonstrated bony abnormality in 50% of the tumor cases, but in only 28% of the entire series of exophthalmos cases. Computerized tomography demonstrated diagnostic soft tissue abnormality in 86% of tumors, 43% of inflammatory diseases, and an overall yield of 62% positive results. Ultrasonography proved the most versatile test for evaluation of orbital soft tissues, with 80% positive results for tumors, 87% for inflammatory disorders, and 78% overall accurate orbital diagnosis. Erroneous tumor diagnosis of 7% with computerized tomography and 3% with ultrasonography were corrected by combining these two studies, because they tend to err in opposite directions. Combination of ultrasound and CT scan resulted in a 98% correct diagnosis of all types of orbital diseases.

Bone Diseases↗

Bilateral dural arteriovenous malformations simulating dysthyroid ophthalmopathy.

The clinical recognition of dural arteriovenous malformations (AVM) is a challenge to the ophthalmologist. Unilateral dural AVMs produce monocular signs which may simulate orbit disease. A patient with bilateral dural AVMs presenting with bilateral congestive exophthalmos resembling dysthyroid ophthalmopathy is reported. Spontaneous resolution of the ocular manifestations occurred.

Aged↗

Unilateral endocrine exophthalmos. Diagnostic problems in association with computed tomography.

Swollen orbital extraocular muscles may mimic an orbital apex tumor on computed tomography. In five of our patients, in spite of highly suggestive findings on CT scanning, indicating the presence of an orbital apex lesion, the correct diagnosis proved to be endocrine exophthalmos. The value of complementary CT projections and of orbital ultrasonography to assist in the differential diagnosis is discussed, and the additional contribution of orbital phlebography for the confirmation of lesions in the orbital apex is emphasized.

Adult↗

Evaluation of unilateral exophthalmos with ultrasonography: analysis of 258 consecutive cases.

Ultrasound examination has emerged as a valuable technique for defining soft tissue abnormalities of the eye and orbit. As high frequency sound waves (5 to 20 megahertz) are projected through soft tissues, echoes are produced at tissue interfaces. These echoes are displayed on oscilloscopes as either one-dimensional amplitude spikes (A-mode ultrasonography), or as dots integrated into a two-dimensional image representing a thin section through the entire orbit (B-scan ultrasonography). A-mode indicates tissue substance, while B-scan illustrates tissue morphology. With this technique, orbital tumors are clearly distinguished in terms of their location, size, and configuration, as well as the basic tissue type (cystic, solid, angiomatous or infiltrative). Other orbital processes are defined by ultrasonography also, including inflammatory conditions such as diffuse pseudotumor or cellulitis, congestive conditions such as dysthyroid exophthalmos, and orbital hemorrhage. Intracranial and vascular etiologies of exophthalmos have no specific ultrasound signs. In a series of 258 consecutive patients with unilateral exophthalmos examined with ultrasonography, diagnosis of tumor was made in 26 percent (66 cases). Overall accuracy of orbital tumor diagnosis by ultrasonography was 94 percent in this series. Tumor localization, configuration, and extent indicated by the test aided in selecting surgical approaches. Other patients in the series were diagnosed ultrasonically as a variety of other entities, mostly inflammatory and dysthyroid exophthalmos. Normal ultrasound studies were found in 19 percent. None of these patients had subsequent diagnosis of tumor. Diagnostic ultrasonography is capable of detecting orbital tumors and distinguishing them from inflammatory, congestive, and other causes of exophthalmos with a high degree of reliability. The test is painless, well tolerated, non-invasive, and non-toxic. It now has a prominent role in evaluation of any patient with exophthalmos.

Abscess↗

Congenital orbital teratoma: report of a case with visual preservation.

Congenital orbital teratoma is a rare, but benign cause of unilateral exophthalmos in infants, and therefore a worthwhile differential diagnosis to consider. Despite the grotesque and alarming external appearance of the eye, both it and visual function can be effectively preserved in certain instances with early intervention. A review of the literature accompanies the report of one such case of a successfully salvaged eye following removal of the teratoma. Clinical recommendations are included.

Child, Preschool↗

Comparison of ultrasonography, computerized tomography (EMI scan), and radiographic techniques in evaluation of exophthalmos.

A series of 342 consecutive patients with unilateral exophthalmos of confirmed etiology have been studied with a combination of clinical investigative techniques. High resolution B-scan ultrasonography and computerized tomography proved to be the most valuable tests for detecting orbital tumors and inflammatory conditions. Ultrasonography demonstrated primary orbital tumors but failed to show intracranial and some secondary tumors. Computerized tomography demonstrated primary, secondary, and intracranial tumors but not cystic masses. Inflammatory conditions such as Graves' disease and pseudotumor were characterized by ultrasonography also, while computerized tomography was not reliable for this. Correct diagnosis of orbital abnormalities in this series was 82% with ultrasonography and 72% with computerized tomography. Combined accuracy of these two complementary tests was 97% for tumor diagnosis. Conventional radiography and polytomography revealed secondary bony changes but not primary orbital tumors and inflammation. Orbital venography and arteriography had a low yield with tumors but were essential for demonstrating arteriovenous abnormalities. Orbital diagnosis has been improved significantly with the two newer techniques of ultrasonography and computerized tomography.

Computers↗