Measurement of Optic Nerve Sheath Diameter: Differences between Methods? A Pilot Study

Abstract

Background: Quantification of the optic nerve sheath diameter is a promising approach for the detection of elevated intracranial pressure. The comparability of current methods is unclear. The objective of this study was to assess the relationship between optic nerve sheath diameter as measured with computed tomography, magnetic resonance tomography and ultrasound in patients without known optic nerve disease or increased intracranial pressure.

Patients and Methods: 15 patients (60.8 [years] ± 16.73 SD; 7 female) with paranasal sinus pathology in whom computed tomography and magnetic resonance imaging were performed underwent optic nerve sheath diameter measurements by ultrasound, as well as an ophthalmological examination. Ultrasound-, computed tomography- and magnetic resonance imaging-derived maximal optic nerve sheath diameter values 3 mm behind the globe were compared.

Results: Optic nerve sheath diameter measured (n = 30) by ultrasound (mean 6.2 [mm] ± 0.84 SD) was significantly (p < 0.01) higher than optic nerve sheath diameter in computed tomography (5.2 ± 1.11) or magnetic resonance imaging (5.3 ± 1.14). There was no significant (p = 0.24) difference between optic nerve sheath diameter measured in computed tomography and magnetic resonance tomography.

Conclusions: The comparability of optic nerve sheath diameter measurements in patients without known optic nerve disease and assumed normal intracranial pressure appears to be given between computed tomography and magnetic resonance tomography, while comparability between ultrasound and computed tomography or magnetic resonance tomography seems to be less reliable.

Zusammenfassung

Hintergrund: Die Messung des Optikusscheidendurchmessers mit Frage nach intrakranieller Druckerhöhung wird zunehmend propagiert. Die Vergleichbarkeit der verfügbaren Methoden ist unklar. Diese Studie vergleicht die Optikusscheidendurchmesser gemessen mittels Computertomografie, Magnetresonanztomografie und Ultraschall bei Patienten ohne bekannte Pathologie des Nervus opticus oder erhöhtem Hirndruck.

Patienten und Methoden: Bei 15 Patienten (60,8 [J] ± 16,73 SD; 7 Frauen) mit Nasennebenhöhlen-Pathologie und vorliegender Computertomografie und Magnetresonanztomografie wurde eine Ultraschalluntersuchung mit Optikusscheidendurchmesser-Messung und eine umfassende Augenuntersuchung durchgeführt. Die maximalen Optikusscheidendurchmesser aus Computertomografie, Magnetresonanztomografie und Ultraschall, jeweils 3 mm hinter dem Bulbus, wurden verglichen.

Ergebnisse: Die Optikusscheidendurchmesser (n = 30) gemessen mit Ultraschall (Mittelwert 6,2 [mm] ± 0,84 SD) waren signifikant (p < 0,01) größer als die Optikusscheidendurchmesser in Computertomografie (5,2 ± 1,11) oder Magnetresonanztomografie (5,3 ± 1,14). Computertomografie und Magnetresonanztomografie unterschieden sich nicht signifikant (p = 0,24).

Schlussfolgerungen: Bei Patienten ohne bekannte Pathologie des Nervus opticus oder erhöhtem Hirndruck scheint die Vergleichbarkeit von Optikusscheidendurchmesser-Messungen mittels Computertomografie und Magnetresonanztomografie gegeben, während die Vergleichbarkeit von Computertomografie und Ultraschall sowie Magnetresonanztomografie und Ultraschall weniger zuverlässig erscheint.

Schlüsselwörter

Optikusscheidendurchmesser - Computertomografie - Magnetresonanztomografie - Ultraschall

Key words

optic nerve sheath diameter - computed tomography - magnetic resonance imaging - ultrasound

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