Fat-Suppressed MRI Outperforms 3D-GRE for Detecting Meningeal Disease in Cats and Dogs

Comparative study of meningeal enhancement in canine and feline otitis media-interna: 3D-gradient-echo vs. fat-suppressed turbo-spin-echo–T1-weighted sequences in MRI

Florian Graf, Matthias Dennler, Katrin Beckmann, Nico Mauri, Mariano Makara, Adriano Wang-Leandro

Background

Otitis media–interna in dogs and cats can lead to serious intracranial complications, making early and accurate detection of meningeal enhancement essential. MRI is the primary diagnostic tool, but the optimal T1-weighted post-contrast sequence for detecting meningeal pathology remains unclear. Previous studies indicate potential benefits of fat-suppression for enhancing detection, yet no direct comparison had been performed between fat-suppressed turbo-spin-echo T1-weighted (FS-TSE-T1W) sequences and 3D-gradient-echo T1-weighted (3D-GRE-T1W) sequences. This study aimed to determine which sequence better detects meningeal enhancement and to assess observer agreement.

Methods

This retrospective study evaluated MRI examinations (2017–2023) of dogs and cats diagnosed with otitis media–interna, requiring availability of both FS-TSE-T1W and 3D-GRE-T1W post-contrast sequences. A control group was selected based on normal neurological exams, normal CSF (when available), and complete bilateral cochlear suppression on T2-FLAIR. Five blinded observers independently reviewed each sequence twice, assessing presence and characteristics of meningeal enhancement. Detection rates were statistically compared via Student’s t-test, while inter- and intra-observer agreement was evaluated using Fleiss’ and weighted kappa statistics.

Results

A total of 141 animals (61 dogs, 80 cats) met inclusion criteria: 120 with otitis media–interna and 21 controls. Observers detected meningeal enhancement significantly more frequently with FS-TSE-T1W than with 3D-GRE-T1W (p < 0.01), a difference driven primarily by feline cases. Detection did not differ significantly between sequences in dogs. Inter-observer agreement was substantial for both FS-TSE-T1W (κ = 0.735) and 3D-GRE-T1W (κ = 0.701), with no meaningful differences between species. Intra-observer agreement was substantial to near-perfect across all observers. Meningeal splitting was identified in up to 13 cases across both sequences. CSF abnormalities were present in 16 of 53 evaluated cases but did not reliably predict MRI enhancement.

Limitations

The study lacked histopathologic confirmation of meningeal pathology, limiting definitive classification of true versus false positives. MRI acquisition parameters varied due to the retrospective design. Potential recall and cognitive bias could not be fully excluded despite anonymization and randomization. Evaluation focused solely on the two sequences of interest, without inclusion of subtraction imaging or other advanced techniques that may influence diagnostic performance.

Conclusions

FS-TSE-T1W sequences demonstrated a significantly higher detection rate of meningeal enhancement than 3D-GRE-T1W, particularly in cats. Despite this increased sensitivity, both sequences achieved similarly high inter- and intra-observer agreement. Incorporating a post-contrast FS-TSE-T1W sequence into standard MRI protocols for evaluating otitis media–interna in dogs and cats appears justified, though caution is warranted to avoid over-interpretation of normal meningeal patterns.

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