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Published on: February 29, 2020
The round window sign: a sensitive sign to detect perilymphatic fistulae on delayed postcontrast 3D-FLAIR sequence
Frédérique Dubrulle1, Victor Chaton2, Michael Risoud3
1Imaging Department, Head and Neck Unit, Huriez Hospital, CHU Lille, 59037, Lille, France. frederique.dubrulle@chru-lille.fr.
Objectives:
The aim of this study is to assess the diagnostic performance of a new MR sign, named the round window sign (RWS), to diagnose perilymphatic fistula (PLF) in a population of patients with chronic cochleo-vestibular symptoms, classified as definite or probable Menière's disease (MD).
Methods:
A total of 164 patients (mean age 52 ± 35 years) with chronic cochleo-vestibular symptoms underwent MRI, between 4 and 5 h after intravenous gadoteric acid injection (Dotarem®, 0.1 mmol/kg). MRI exploration was carried out on a 3-T Achieva® TX scanner. We analyzed the presence of the RWS, defined as a nodular FLAIR high signal in the round window (RW) and the presence of associated saccular hydrops. When this RWS was present, a temporal bone CT scan was performed and the RW was analyzed.
Results:
Of the 164 patients with definite MD (85 patients) or probable MD (79 patients), we found the RWS in 18 (11%), and 17/18 were classified into the group of probable MD. All these 18 patients showed other MR sequences considered as normal, including heavily weighted T2 imaging. Among these 18 patients, the temporal bone CT examination presented a filling of the RW in 13 patients (72%) and no filling of the RW in 5 patients (28%). Seven patients were surgically managed confirming in vivo the PLF diagnosis. The RWS was associated with the presence of a saccular hydrops in 4 cases.
Conclusion:
Delayed postcontrast 3D-FLAIR may reveal perilymphatic fistulae in patients with probable Menière's disease using the round window sign.
Key Points:
• MRI with delayed acquisition can detect perilymphatic fistulae with perfect sensitivity, based on the presence of the round window sign. • This visual sign is only visible on a 3D-FLAIR sequence. • 3D-FLAIR sequence with delayed acquisition is more sensitive than temporal bone CT scan examination in detecting PLF.
Insights
A new MRI sign, the round window sign (RWS), shows promise for diagnosing perilymphatic fistulae (PLF) in Menière
Area of Science:
- Radiology and Imaging
- Otolaryngology
- Neurology
Background:
- Perilymphatic fistula (PLF) is a challenging diagnosis in patients with chronic cochlear and vestibular symptoms.
- Menière's disease (MD) is a common condition presenting with such symptoms, often requiring accurate diagnosis for effective management.
- Current diagnostic methods for PLF can be limited in sensitivity and specificity.
Purpose of the Study:
- To evaluate the diagnostic performance of a novel magnetic resonance imaging (MRI) finding, the round window sign (RWS).
- To assess the utility of RWS in diagnosing PLF in patients with suspected Menière's disease.
- To compare the sensitivity of RWS on delayed postcontrast 3D-FLAIR MRI with temporal bone CT scans for PLF detection.
Main Methods:
- 164 patients with chronic cochlear-vestibular symptoms, classified as definite or probable MD, underwent delayed postcontrast MRI (4-5 hours after gadoteric acid injection) on a 3-T scanner.
- The presence of the RWS, characterized by a nodular FLAIR high signal in the round window (RW) with or without saccular hydrops, was analyzed.
- Temporal bone CT scans were performed for patients with a positive RWS to further evaluate the RW; surgical confirmation was pursued in select cases.
Main Results:
- The RWS was identified in 18 patients (11%), predominantly in those with probable MD (17/18).
- In patients with RWS, temporal bone CT showed RW filling in 13 (72%) and no filling in 5 (28%).
- Seven patients underwent surgery, confirming the PLF diagnosis in vivo; RWS was associated with saccular hydrops in 4 cases.
Conclusions:
- Delayed postcontrast 3D-FLAIR MRI, utilizing the round window sign (RWS), can effectively detect perilymphatic fistulae (PLF) in patients with probable Menière's disease.
- The RWS, visualized on 3D-FLAIR sequences, demonstrates perfect sensitivity for PLF detection.
- This MRI technique shows superior sensitivity compared to temporal bone CT scans for identifying PLF.
