A comparison of imaging techniques for diagnosing drusen of the optic nerve head.

OBJECTIVE

To determine the best imaging procedure for diagnosing drusen of the optic nerve head.

METHODS

We reviewed retrospectively the clinical records of 142 patients (261 eyes) with suspected drusen of the optic disc. The patients were referred to our hospital over a 7-year period and evaluated by B-scan echography, orbital computed tomographic (CT) scan, and/or preinjection control photography for detection of autofluorescence. The relative diagnostic yield of these imaging techniques was compared.

RESULTS

Thirty-six of the 261 eyes were evaluated using all 3 imaging techniques, with drusen of the optic nerve head diagnosed in 21 eyes. Findings from B-scan echography were positive in all 21 eyes compared with 9 positive findings from the CT scans and 10 positive findings from the preinjection control photographs (P<.01 for B-scan echography vs both CT scan and preinjection control photography). In 82 eyes with suspected buried drusen of the optic nerve head, B-scan echography showed drusen in 39 eyes compared with 15 eyes in which drusen were shown using preinjection control photography (P<.001). In the whole series, no diagnosis of drusen was made by either preinjection control photography or CT scan and was missed on B-scan echography.

CONCLUSIONS

Drusen of the optic nerve head are diagnosed most reliably using B-scan echography compared with both preinjection control photography and CT scans. Preinjection control photography should be performed mainly when confirmation of visible drusen of the optic disc is desired. Neuroimaging using CT is suitable to exclude diagnosis of an intracranial mass lesion and possibly to detect buried drusen of the optic nerve head at the same time.