Signal intensity pattern of the normal oculomotor nerve on contrast-enhanced 3D FLAIR at 3.0 T MRI

Abstract

Purpose The aim of this study was to depict the signal intensity pattern of the normal oculomotor nerve demonstrated on contrast-enhanced three-dimensional fluid-attenuated inversion recovery images. Materials and methods Eighty-one patients were included in the study. Contrast-enhanced three-dimensional fluid-attenuated inversion recovery images with magnetisation-prepared rapid acquisition were reconstructed and evaluated in the coronal plane. The signal intensity of the cisternal segment of the oculomotor nerve was graded into a visual scale of 1 to 5 as compared to the white matter, grey matter and the pituitary stalk. The signal intensity ratio of the oculomotor nerve was consequently measured. Results By using the visual scale, more than half of the oculomotor nerves showed higher signal intensity than the grey matter signal on contrast-enhanced three-dimensional fluid-attenuated inversion recovery images (59.3–80.2%). It can demonstrate a signal intensity similar to the pituitary stalk (14.8%) by visualisation. None of them showed signal intensity equal to the normal white matter signal. By signal intensity measurement, the mean signal intensity ratio of oculomotor nerves to white matter equals 1.54±0.20 (95% confidence interval (CI) 1.51–1.57); mean signal intensity ratio to grey matter equals 1.16±0.15 (95% CI 1.14–1.18); mean signal intensity ratio to the pituitary stalk equals 0.68±0.10 (95% CI 0.64–0.70). Conclusions The normal oculomotor nerve visualised on contrast-enhanced three-dimensional fluid-attenuated inversion recovery images has a higher signal intensity than the white matter and may have a signal intensity similar to the grey matter or the pituitary stalk. The high signal intensity of the oculomotor nerve in contrast-enhanced three-dimensional fluid-attenuated inversion recovery should not be misinterpreted as a pathology.

Clinical Value of 3D-FLAIR MRI in Idiopathic Sudden Sensorineural Hearing Loss

“…21 Accumulating studies have confirmed that 3.0T MRI, especially the 3D-FLAIR sequence, has good sensitivity and specificity to the alterations in ISSNHL inner ear signals. 17,22 The application of 3D-FLAIR MRI can assist clinicians to find different pathological changes in the inner ear on time. Therefore, 3D-FLAIR MRI has a potentially important clinical value for the possible pathological mechanism and prognosis assessment of ISSNHL.…”

Neuroradiologie für den Augenarzt. Teil 2: Efferenz

“…Signalverstärkungen im zisternalen Segment sind bei sog. ischämischen, mikrovaskulären Paresen schon mehrfach beschrieben worden 16 , 17 . Bezeichnenderweise fehlt bei manchen Signalverstärkungen – so wie in unserem genannten Fallbeispiel – das klinische Korrelat einer Hirnnervenparese 16 , 17 .…”

“…ischämischen, mikrovaskulären Paresen schon mehrfach beschrieben worden 16 , 17 . Bezeichnenderweise fehlt bei manchen Signalverstärkungen – so wie in unserem genannten Fallbeispiel – das klinische Korrelat einer Hirnnervenparese 16 , 17 . Obwohl klinisch nur eine einseitige Okulomotoriusparese vorliegt, zeigt der linke nicht betroffene N. oculomotorius eine nahezu identische Signalverstärkung.…”

“…Obwohl klinisch nur eine einseitige Okulomotoriusparese vorliegt, zeigt der linke nicht betroffene N. oculomotorius eine nahezu identische Signalverstärkung. Gleiches gilt für eine Signalverstärkung nach Kontrastmittelgabe (Überblick in 17 , 18 ). In einer Studie mit 45 Patienten mit isolierter Okulomotoriusparese und vermuteter mikrovaskulärer ischämischer Genese wurden die Signalveränderungen im Bereich des Sinus cavernosus und nicht in den zisternalen Abschnitten der Nerven beobachtet 18 , was sich mit Beobachtungen in weiteren Studien deckt 19 , 20 .…”