Comparison of contrast effect on the cochlear perilymph after intratympanic and intravenous gadolinium injection

Detection and grading of endolymphatic hydrops in Menière disease using MR imaging

BACKGROUND AND PURPOSE

Endolymphatic hydrops has been recognized as the underlying pathophysiology of Menière disease. We used 3T MR imaging to detect and grade endolymphatic hydrops in patients with Menière disease and to correlate MR imaging findings with the clinical severity.

MATERIALS AND METHODS

MR images of the inner ear acquired by a 3D inversion recovery sequence 4 hours after intravenous contrast administration were retrospectively analyzed by 2 neuroradiologists blinded to the clinical presentation. Endolymphatic hydrops was classified as none, grade I, or grade II. Interobserver agreement was analyzed, and the presence of endolymphatic hydrops was correlated with the clinical diagnosis and the clinical Menière disease score.

RESULTS

Of 53 patients, we identified endolymphatic hydrops in 90% on the clinically affected and in 22% on the clinically silent side. Interobserver agreement on detection and grading of endolymphatic hydrops was 0.97 for cochlear and 0.94 for vestibular hydrops. The average MR imaging grade of endolymphatic hydrops was 1.27 ± 0.66 for 55 clinically affected and 0.65 ± 0.58 for 10 clinically normal ears. The correlation between the presence of endolymphatic hydrops and Menière disease was 0.67. Endolymphatic hydrops was detected in 73% of ears with the clinical diagnosis of possible, 100% of probable, and 95% of definite Menière disease.

CONCLUSIONS

MR imaging supports endolymphatic hydrops as a pathophysiologic hallmark of Menière disease. High interobserver agreement on the detection and grading of endolymphatic hydrops and the correlation of MR imaging findings with the clinical score recommend MR imaging as a reliable in vivo technique in patients with Menière disease. The significance of MR imaging detection of endolymphatic hydrops in an additional 22% of asymptomatic ears requires further study.

MR imaging of Ménière's disease after combined intratympanic and intravenous injection of gadolinium using HYDROPS2

Endolymphatic hydrops (EH) in Ménière's disease is currently evaluated by 3-dimensional (3D)-real inversion recovery (IR) sequence after intratympanic (IT) administration of gadolinium (Gd) or by heavily T2-weighted (hT2W)-3D-fluid-attenuated IR (FLAIR) sequence after intravenous (IV) injection of Gd. Unilateral IT injection is usually performed. We employed a method in which we simultaneously administered contrast into one ear intravenously (IV side) and into the other ear both intravenously and intratympanically (IT + IV side) to evaluate EH in 10 patients with Ménière's disease. We then compared a HYDROPS2 image obtained by subtracting magnetic resonance cisternography from hT2W-3D-FLAIR with an image obtained by 3D-real IR and found that we could evaluate EH in all ears on the HYDROPS2 image but only in the IT + IV side on the 3D-real IR image.

Visualization of white matter tracts using a non-diffusion weighted magnetic resonance imaging method: does intravenous gadolinium injection four hours prior to the examination affect the visualization of white matter tracts?

Objectives

Visualization of white matter (WM)-tracts such as the corticospinal tract (CST), medial lemniscus (ML), and superior cerebellar peduncle (SCP) using delayed enhanced (DE)-heavily T2-weighted three-dimensional fluid-attenuated inversion-recovery (hT2w-3D-FLAIR) imaging has recently been reported. In that report, all patients were clinically suspected of having Ménière’s disease, because DE-hT2w-3D-FLAIR imaging of the inner ear has been reported to separately visualize perilymph and endolymph fluid and can identify the presence of endolymphatic hydrops. Therefore, the previous report could not rule out the possible effect of delayed enhancement. From this perspective, the purpose of this study was to elucidate if the use of gadolinium affects the visualization of WM-tracts on hT2w-3D-FLAIR.

Materials and Methods

The records of nine patients with suspected Ménière’s disease who underwent plain (P) and DE-hT2w-3D-FLAIR by 3-Tesla were retrospectively analyzed. The regions of interest were set on the CST, ML, and SCP, and on contiguous brain parenchyma: The thalamus (Th), pontine parenchyma (PP), and cerebellar parenchyma (CP), respectively. The signal intensity ratio between each WM-tract and the relevant contiguous brain parenchyma was calculated for both P- and DE-hT2w-3D-FLAIR images, and statistically compared using paired t-tests.

Results

The CST/Th signal intensity ratio was 3.75±0.67 on P-hT2w-3D-FLAIR and 3.62±0.50 on DE-hT2w-3D-FLAIR (p = 0.24). The ML/PP signal intensity ratio was 2.19±0.59 on P-hT2w-3D-FLAIR and 2.08±0.53 on DE-hT2w-3D-FLAIR (p = 0.25). The SCP/CP signal intensity ratio was 4.08±0.91 on P-hT2w-3D-FLAIR and 4.04±0.96 on DE-hT2w-3D-FLAIR (p = 0.43). There were no significant differences in the signal intensity ratios between P- and DE-hT2w-3D-FLAIR images.

Conclusions

The use of gadolinium is not necessary for visualization of WM-tracts using hT2w-3D-FLAIR, and P-hT2w-3D-FLAIR without gadolinium may have future clinical applications as an imaging procedure.

Gadolinium distribution in cochlear perilymph: differences between intratympanic and intravenous gadolinium injection

INTRODUCTION

Three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) imaging 24 h after intratympanic gadolinium injection (IT method) or 4 h after intravenous injection (IV method) has been used to visualize endolymphatic hydrops in Ménière's disease. The aims of this study were to evaluate the difference in gadolinium distribution in cochlear perilymph between the two methods by comparing the enhancement of the basal and apical turns and clarify the pharmacokinetics in cochlear perilymph.

METHODS

A total of 24 ears of 22 patients who underwent the IT method (gadolinium-diethylene-triamine pentaacetic acid was diluted eightfold with saline) and 28 ears of 17 patients who underwent the IV method (double dose of gadoteridol (0.5 mmol/ml); 0.2 mmol/kg body weight in total amount) at 3 T was analyzed retrospectively. Regions of interest of the perilymph of the cochlear basal turn (B), of the apical turn (A), and the medulla oblongata (M) were determined on each patient. The signal intensity ratios between B and M (BMR), A and M (AMR), and A and B (ABR) were subsequently evaluated.

RESULTS

The IT-BMR (2.63 ± 1.22) was higher than the IV-BMR (1.46 ± 0.45) (p < 0.001). There was no significant difference between the IT- (1.46 ± 0.76) and IV-AMRs (1.21 ± 0.48) (p = 0.15). The IT-ABR (0.58 ± 0.17) was lower than the IV-ABR (0.84 ± 0.22) (p < 0.001).

CONCLUSION

Gadolinium was predominantly distributed in the basal turn compared with the apical turn in the IT method, whereas it was more uniformly distributed in the IV method. These characteristics might reflect the distribution of therapeutic medications administered either intratympanically or systemically.