Is CT or MRI the optimal imaging investigation for the diagnosis of large vestibular aqueduct syndrome and large endolymphatic sac anomaly?

Abstract

Background and purposeWe explored whether there was a difference between measurements obtained with CT and MRI for the diagnosis of large vestibular aqueduct syndrome or large endolymphatic sac anomaly, and whether this influenced diagnosis on the basis of previously published threshold values (Valvassori and Cincinnati). We also investigated whether isolated dilated extra-osseous endolymphatic sac occurred on MRI. Secondary objectives were to compare inter-observer reproducibility for the measurements, and to investigate any mismatch between the diagnoses using the different criteria.Materials/methodsSubjects diagnosed with large vestibular aqueduct syndrome or large endolymphatic sac anomalies were retrospectively analysed. For subjects with both CT and MRI available (n = 58), two independent observers measured the midpoint and operculum widths. For subjects with MRI (± CT) available (n = 84), extra-osseous sac widths were also measured.ResultsThere was no significant difference between the width measurements obtained with CT versus MRI. CT alone diagnosed large vestibular aqueduct syndrome or large endolymphatic sac anomalies in 2/58 (Valvassori) and 4/58 (Cincinnati), whilst MRI alone diagnosed them in 2/58 (Valvassori). There was 93% CT/MRI diagnostic agreement using both criteria. Only 1/84 demonstrated isolated extra-osseous endolymphatic sac dilatation. The MRI-based LVAS/LESA diagnosis was less dependent on which criteria were used. Midpoint measurements are more reproducible between observers and between CT/MR imaging modalities.ConclusionSupplementing MRI with CT results in additional diagnoses using either criterion, however, there is no net increased diagnostic sensitivity for CT versus MRI when applying the Valvassori criteria. Isolated enlargement of the extra-osseous endolymphatic sac is rare.

Perilymphatic Fistula: A Review of Classification, Etiology, Diagnosis, and Treatment

“…The conductive component of the hearing loss in EVA is likely due to the third window. Both MRI and high-resolution CT are sufficient for evaluating EVA ( 79 ); however, specific criteria for abnormal aqueduct width range from >1 to >2 mm ( 80 , 81 ). ECA is a potentially related condition ( 82 ) with a similar mechanism of hearing loss.…”

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“…Oblique reformation of the images may be required to identify such findings. Diameter more than 2 mm at operculam and more than 1mm at midpoint is considered to be an enlarged vestibular aquaduct as per Cinncinatti criteria, meanwhile, a diameter more than 1.5mm is considered to be enlarged vestibular aquaduct as per Valvassori criteria [3]. As per both criteris its evident that in our case the vestibular duct on left side is enlarged.…”

Pre- and post-operative imaging of cochlear implants: a pictorial review

“…This syndrome shows an enlarged vestibular aqueduct with the otherwise regular cochlea, vestibule, and semicircular canals [ 31 , 32 ]. Cincinnati criteria (midpoint > 0.9 mm or operculum > 1.9 mm) and the Valvassori criterion (midpoint > or = 1.5 mm) for enlarged vestibular aqueduct are used.…”