Imaging Endolymphatic Hydrops at 3 Tesla Using 3D-FLAIR with Intratympanic Gd-DTPA Administration

Abstract

Purpose: Visualization of endolymphatic hydrops by 3-dimensional ‰uid-attenuated inversion recovery-FLAIR using conventional turbo-spin-echo (3D-FLAIR-CONV) after intratympanic injection of Gd-DTPA has been reported in patients with M áeni àere's disease. Compared to 3D-FLAIR-CONV used in previous studies, the addition of a variable ‰ip-angle technique (3D-FLAIR-VFL) enables very long echo trains and, therefore, shorter scan times. We evaluated whether 3D-FLAIR-VFL could replace 3D-FLAIR-CONV in detecting endolymphatic hydrops after intratympanic Gd-DTPA administration.Methods: Eleven patients were included in this study. Twenty-four hours after Gd-DTPA injection, we performed 3D-FLAIR-CONV and 3D-FLAIR-VFL imaging at 3T. We compared the contrast-to-noise ratio (CNR) between cochlear ‰uid and the cerebellum between the 2 FLAIR sequences. We subjectively scored the size of the endolymphatic space in the cochlea and vestibule for each patient and correlated the scores with the clinical diagnoses.Results: The CNR of 3D-FLAIR-CONV was signiˆcantly higher than that of 3D-FLAIR-VFL. Scores for the size of endolymphatic space in the vestibule were identical between the 2 sequences; however, those in the cochlea disagreed in 3 cases. 3D-FLAIR-CONV correlated better with the clinical diagnoses.Conclusions: Currently, we may not be able to replace 3D-FLAIR-CONV with 3D-FLAIR-VFL, at least not with the scanning parameters used in the present study.

Comparison of Contrast Effect on the Cochlear Perilymph after Intratympanic and Intravenous Gadolinium Injection

“…In addition, the IT-method is a useful preliminary prediction tool of drug distribution to the inner ear, such as the distribution of gentamicin and steroids after intratympanic administration. [11][12][13][14] For the patients with an inner ear disorder who have restrictions in daily life caused by vertigo or hearing loss, further imaging investigation of the inner ear and preliminary prediction of drug distribution to the inner ear are extremely important matters to improve their quality of life. Therefore, the features of the IT-method observed in the present study warrant considering their advantage for the close investigation of inner ear disorders.…”

“…In animal experiments by using intratympanic gadolinium injection, gadolinium was diluted 8-fold with saline, which is the concentration of gadolinium used in the previous and the present human studies, and showed no marked effect on the stria vascularis. 28 The reports describing intratympanic gadolinium injection in human subjects have been published from several institutions, including ours, [11][12][13][14][15][23][24][25][29][30][31] and no marked side effects in the inner ear relating to intratympanic gadolinium injection have been reported on clinical application at present, to the best of our knowledge. In addition, intravenously administered gadolinium has been reported to infiltrate inner ear perilymph, 16,17,22,23 and no marked side effects in the inner ear relating to IV gadolinium injection have been reported in the clinical application at present.…”

“…[7][8][9][10] 3D-FLAIR imaging 24 hours after intratympanic gadolinium injection (IT-method) has been reported to visualize perilymph and endolymph fluid separately and to enable preliminary prediction of drug distribution to the inner ear, such as gentamicin and steroids. [11][12][13][14] The sensitivity of gadoliniumagent detection in perilymph 24 hours after intratympanic gadolinium injection on 3D-FLAIR has been reported to be superior to that on 3D-T1-weighted imaging or on the 3D-constructive interference in steady state sequence, 15 suggesting that 3D-FLAIR would be most suited for signal-intensityalteration assessment 24 hours after intratympanic gadolinium injection. On the other hand, 3D-FLAIR imaging 4 hours after IV gadolinium injection (IV-method) also has been recently reported to visualize perilymph and endolymph fluid separately, in a less invasive manner than the IT-method, and also enables ascertaining the presence of endolymphatic hydrops in bilateral cochleae.…”

Estimation of Gadolinium-induced T1-shortening with Measurement of Simple Signal Intensity Ratio between the Cochlea and Brain Parenchyma on 3D-FLAIR: Correlation with T1 Measurement by TI Scout Sequence

“…The features of this variable ‰ip-angle sequence have been reported elsewhere. 18,22 This sequence allows the use of very long echo-train lengths, in the range of 100-200, without severe blurring, while maintaining contrast similar to that of 3D-FLAIR-CONV, even with a long eŠective echo time.…”

“…We acquired 3D images in all patients: 3D-constructive interference in the steady state (CISS); 3D-FLAIR by conventional turbo spin echo (3D-FLAIR-CONV); 1,16 3D-FLAIR by variable ‰ip angle turbo spin echo (3D-FLAIR-VFL); 18 and 3D-inversion recovery with real reconstruction (3D-real IR) 19 as well as TI scout images. To evaluate signal intensity, we analyzed 3D-FLAIR-VFL and TIscout images because the 0.8-mm slice thickness of the 3D-FLAIR-VFL protocol is less susceptible to partial volume averaging artifact than the 2-mm slice thickness of 3D-FLAIR-CONV.…”