Non-contrast magnetic resonance imaging for monitoring patients with acoustic neuroma.

OBJECTIVE

To assess the feasibility of non-contrast T2-weighted magnetic resonance imaging as compared to T1-weighted post-contrast magnetic resonance imaging for detecting acoustic neuroma growth.

METHODS

Adult patients with acoustic neuroma who underwent at least three magnetic resonance imaging scans of the internal auditory canals with and without contrast in the past nine years were identified. T1- and T2-weighted images were reviewed by three neuroradiologists, and tumour size was measured. Accuracy of the measurements on T2-weighted images was defined as a difference of less than or equal to 2 mm from the measurement on T1-weighted images.

RESULTS

A total of 107 magnetic resonance imaging scans of 26 patients were reviewed. Measurements on T2-weighted magnetic resonance imaging scans were 88 per cent accurate. Measurements on T2-weighted images differed from measurements on T1-weighted images by an average of 1.27 mm, or 10.4 per cent of the total size. The specificity of T2-weighted images was 88.2 per cent and the sensitivity was 77.8 per cent.

CONCLUSION

The T2-weighted sequences are fairly accurate in measuring acoustic neuroma size and identifying growth if one keeps in mind the caveats associated with the tumour characteristics or location.