Intensity of gadolinium enhancement on MRI is useful in differentiation of intracochlear inflammation from tumor.

OBJECTIVE

Magnetic resonance imaging is the gold standard in retrocochlear imaging; however, its role in management of inner ear diseases remains poorly defined. In this study, we investigate the utility of MRI in defining the nature of intracochlear pathology.

STUDY

DESIGN

A retrospective review of 11 patients with inner ear abnormalities on MRI between 2010 and 2013. Patients' diagnosis included cholesteatoma, labyrinthitis, meningitis, and intralabyrinthine schwannoma.

SETTING

Tertiary care hospital.

MAIN OUTCOME MEASURES: T1, T2, and postcontrast signal intensities were measured within the lesion and normalized in reference to the contralateral normal cochlea. The following ratios were calculated: T1 postgadolinium lesion/contralateral cochlea, T2 lesion/contralateral cochlea and T1 lesion/contralateral cochlea. Statistical analysis was conducted using the unpaired Student's t test using IBM SPSS Statistics version 20.0.0.

RESULTS

The relative intensity ratios were useful in defining the nature of inner ear lesion. Normalized T1 postgadolinium lesion intensities were significantly higher in the tumor group (3.98 ± 0.880 versus 1.71 ± 0.370, p < 0.0002). Normalized T1 precontrast signal intensities were higher in tumors (1.33 ± 0.200 versus 0.842 ± 0.426, p < 0.0626), and T2 values were lower in tumors (0.838 ± 0.491 versus 1.10 ± 0.305, p < 0.317); however, these did not reach significance.

CONCLUSION

Intensity of gadolinium enhancement on MRI is useful in differentiation of inflammation from tumors; normalized T1 postgadolinium intensity ratio greater than 3 is strongly suggestive of intralabyrinthine tumor.