Accuracy of crescent sign on ocular ultrasound in diagnosing papilledema

AIM

To study the usefulness of orbital ultrasonography in the diagnosis of papilledema.

METHODS

Fifty patients who were referred to the neurophthalmology clinic and clinically suspected to have papilledema were selected. Thorough, clinical examination with slitlamp biomicroscopy and visual acuity assessment was done. These patients underwent ultrasonography to demonstrate the crescent sign. The patients were further evaluated with the neurologist and magnetic resonance imaging (MRI) thus confirming the diagnosis of papilledema. The results of our ultrasonographic evaluation were correlated with final diagnosis after thorough clinical evaluation, imaging and the neurologist’s opinion.

RESULTS

Out of 50 patients diagnosed having papilledema on MRI, 46 (92%) showed crescent sign on B scan ultrasonography. Headache was most common presenting complaint in 47 (94%) and idiopathic intracranial hypertension was most common underlying cause of papilledema in 30 (60%) cases.

CONCLUSION

“Crescent sign” seen on ultrasonography is a sensitive tool for diagnosis of papilledema. It is cost effective, less cumbersome and effective tool to differentiate between papilledema and pseudo papilledema before subjecting the patients to costly investigations like MRI. A positive crescent sign should always be followed by MRI to find out the cause of papilledema.

Diagnostic Ophthalmic Ultrasound for Radiologists

Ophthalmic ultrasound is an invaluable tool that provides quick and noninvasive evaluation of the eye and the orbit. It not only allows the clinicians to view structures that may not be visible with routine ophthalmic equipment or neuroimaging techniques but also provides unique diagnostic information in various ophthalmic conditions. In this article, the basic principles of ophthalmic ultrasound and examination techniques are discussed. Its clinical application is illustrated through a variety of ocular pathologic abnormalities (eg, narrow angles, ciliary body tumor, detached retina, choroidal melanoma, and papilledema).

Update on advanced imaging options for thyroid-associated orbitopathy

Thyroid-associated orbitopathy (TAO) is a diverse spectrum of signs and symptoms that appears to have immunologic and pathologic causative factors as diverse as its clinical presentations. Lymphocytes, hormones, and cytokines affect orbital fibroblasts and other similar cells, which exert their effects on orbital tissues, including the extraocular muscles, orbital fat, and optic nerve. This complicated inflammatory cascade and the myriad of clinical findings that result contributes to the active phase of TAO. The distinction between the active and inactive phases of TAO is an important one, as the proper treatment will depend on the disease phase and degree thereof. Several clinical grading scales and scores have been established to help qualify and quantify the disease severity. Aiding clinical exam and acumen, proper and reproducible imaging of the orbit and ocular adnexa is incredibly important to the management of TAO. Orbital ultrasound, computed tomography, magnetic resonance imaging, and scintigraphy each have unique abilities, including quantifying orbital changes, assessing disease activity, correlating orbital findings with clinical changes, guiding appropriate treatment, and monitoring therapeutic responses. Further, study ease, accessibility, cost, sensitivity, specificity, reproducibility, and risks are all important considerations in picking the right test with which to diagnose and follow TAO. This analysis will provide a review of orbital imaging for TAO, including the mechanism of each imaging technique as well as their rationales, advantages, disadvantages, and utilities.