Comprehensive comparison of MR image quality between intratympanic and intravenous gadolinium injection using 3D real IR sequences

The value of gadolinium-enhanced MRI in predicting the development of sudden hearing loss into Ménière's disease

OBJECTIVE

To compare the clinical features of sudden hearing loss (SHL) in patients with and without endolymphatic hydrops (EH), and to investigate the association between SHL with EH and Ménière's disease (MD).

METHODS

The clinical data of 63 SHL patients with first symptoms were evaluated retrospectively. Patients were separated into two groups based on the results of gadolinium-enhanced magnetic resonance imaging: EH and non-EH groups. Independent sample t-test and U-test were used to compare groups for continuous variables, and the chi-squared test, corrected chi-squared test and Bonferroni correction test were used to compare groups for binary and ordinal variables. The binary logistic regression model was utilised for univariate and multivariate analysis of follow-up patient prognosis.

RESULTS

The EH and non-EH groups contained 32 and 31 patients, respectively. The EH group had a higher prevalence of low-tone descending hearing loss. Fifty-one patients were followed for more than 2 years. In the EH group, 11 and 15 patients were diagnosed with sudden sensorineural hearing loss (SSNHL) and MD, respectively, while in the non-EH group, 24 patients were diagnosed with SSNHL and only one with MD. EH, low-tone descending hearing loss and vertigo were risk factors for the diagnosis of MD in a subgroup univariate regression analysis of patients experiencing SHL. EH was found to be a risk factor for the progression of SHL into MD in a multifactor regression analysis.

CONCLUSIONS

Patients with SHL who have EH are more likely to present with low-tone descending hearing loss. EH is a risk factor for the subsequent development of MD.

[Interpretation of consensus on MRI of endolymphatic hydrops in patients with suspected hydropic ear disease and domestic research progress]

Endolymphatic hydrops（EH） is considered the histological hallmark of Meniere's disease. Visualization of EH has been achieved by special sequences of inner ear magnetic resonance imaging（MRI） with gadolinium-based contrast-agent via intravenous or intratympanic administration. Although it has been applied for more than ten years since 2007, a unified view on this technique has not yet been achieved. In 2022, Yang Jun and Duan Maoli et al led the organization to write the international expert consensus on MRI of EH. This article interprets the main contents and reports related progress.

Comparison between 3D-FLAIR and 3D-real IR MRI sequences with visual classification method in the imaging of endolymphatic hydrops in Meniere's disease

BACKGROUND

Clinically, the evidence of endolymphatic hydrops (EH) in Meniere's disease (MD) primarily relies on audiological examinations, such as glycerol tests and electrocochleography, to suggest the presence of EH indirectly. However, these techniques lack sensitivity and specificity, and they do not sufficiently assess the degree of EH. This study aims to explore the application of three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) and three-dimensional real inversion recovery (3D-real IR) sequence imaging of EH in MD and to assess the image quality and grading of EH.

METHODS

The study included 50 patients with definite MD. The 3D-FLAIR and 3D-real IR sequence images were performed 24 h after bilateral intratympanic injection of gadolinium. The image quality of both sequences was reviewed by two experienced radiologists. The vestibular and cochlear EH grades of both sequences were reviewed by two experienced otologists using a visual grading method. The Cohen's kappa and Pearson tests were used to analyze the data.

RESULTS

The reliability of image quality between the two radiologists was excellent (0.7 < kappa < 0.9). There were significant statistical differences in the image quality between the 3D-real IR and 3D-FLAIR sequences (p = 0.023 and p = 0.035, respectively). The reliability for the grading of vestibular and cochlear EH between the two otologists was excellent (0.7 < kappa < 0.9). The 3D-real IR sequence detected more severe hydrops than did the 3D-FLAIR sequence (p < 05).

CONCLUSION

The image quality of the 3D-real IR sequence is better than that of the 3D-FLAIR sequence, and there are differences in the vestibular and cochlear EH grades of both sequences. The sensitivity of the 3D-real IR sequence in the cochlea is higher. The method of visual grading can be applied to both technologies when combined with 3D-real IR.

Endolymphatic Hydrops Magnetic Resonance Imaging in Menire's Disease Patients on a Vertigo Attack

OBJECTIVE

To investigate the characteristics of endolymphatic hydrops (EH) in Menire's disease (MD) patient on a vertigo attack.

STUDY DESIGN

Prospective study.

SETTING

Tertiary referral center.

PATIENTS

Thirty-six MD patients underwent the enhanced magnetic resonance imaging (MRI) examinations of the inner ear on a vertigo attack were enrolled.

MAIN OUTCOME MEASURES

All patients met the diagnostic criteria for MD and underwent intravenous gadolinium injection 4 hours before the MRI examinations. The MRI examinations were performed in MD patients on a vertigo attack.

RESULTS

Various degrees of vestibular EH appeared in almost all affected ears (2 ears had no EH, 11 ears had mild EH, 26 ears had significant EH). The positive rate of vestibular EH was 37/39 (94.9%). Cochlear EH occurred in 29 ears among 39 affected ears (17 ears had mild EH, 12 ears had significant EH).

CONCLUSION

MRI with intravenous gadolinium injection can provide a better assessment of EH in MD patient on a vertigo attack. Vestibular EH seems to be closely related with the vertigo attacks in MD patients, which needs further study.

Inner ear MRI enhancement based on 3D-real IR sequence in patients with Meniere's disease after intravenous gadolinium injection: comparison of different doses used and exploration of a appropriate dose

OBJECTIVES

Three-dimensional inversion-recovery sequence with real reconstruction (3D-real IR) magnetic resonance imaging (MRI) can detect endolymphatic hydrops of the inner ear. We aimed to explore a appropriate dose for intravenous gadolinium injection.

DESIGN

Observational prospective study.

SETTING

Tertiary referral center.

PARTICIPANTS

We collected 90 unilateral definite Meniere's disease patients.

MAIN OUTCOME MEASURES

All enrolled patients were divided into three groups randomly (patients in group A, B and C received gadolinium injection in 1/1.5/2 times doses, respectively). After 4 hours, inner ear MRI scans were applied.

RESULTS

The signal intensities of B-affected ears and C-affected ears were significantly higher than A-affected ears (p < 0.05), however, no difference was found between B-affected ears and C-affected ears (p=0.267). The same conditions also appeared in the three unaffected-ear groups. Moreover, the signal intensities of affected-ear in group A, B and C were significantly higher than that of the corresponding unaffected-ear groups (p < 0.05). Besides, the subjective visual evaluation scores of group B and C were significantly better than that of group A (p < 0.05).

CONCLUSIONS

Intravenous injection of gadolinium in a single dose may be unbefitting for the inner ear imaging based on 3D-real IR MRI, both the applications of gadolinium in 1.5 times and double doses can have a good perilymphatic enhancement effect of inner ear. In order to minimize the use of dose for avoiding or mitigating the adverse reactions and renal damage, 1.5 times dose may be preferred in clinical practice.

Increased signal intensity with delayed post contrast 3D-FLAIR MRI sequence using constant flip angle and long repetition time for inner ear evaluation

PURPOSE

The purpose of this study was to compare the degree of perilymphatic enhancement between 4 hour post-contrast constant flip angle three-dimensional fluid attenuated inversion recovery (3D-FLAIR) images obtained with short repetition time (TR) and those obtained with long TR.

MATERIALS AND METHODS

This single-center, prospective study included patients who underwent MRI of the inner ear with heavily T2-weighted sequence, 3D-FLAIR sequence with a "short" TR of 10,000 ms (s3D-FLAIR) and with a "long" TR of 16,000 ms (l3D-FLAIR). Signal intensity ratio (SIR) and contrast-to-noise ratio (CNR) obtained with s3D-FLAIR and l3D-FLAIR were quantitatively assessed using region of interest (ROI) method and compared. The morphology of the endolymphatic space on both sequences was also evaluated.

RESULTS

From March 2020 to July 2020, 20 consecutive patients were enrolled (9 women and 11 men; mean age, 52.1 ± 14.5 [SD] years; age range: 29-75 years). On l3D-FLAIR images, mean SIR (21.1 ± 8.8 [SD]; range: 7.6-46.1) was significantly greater than that on s3D-FLAIR images (15.7 ± 6.7 [SD]; range: 5.9-33.4) (P < 0.01). On l3D-FLAIR images, mean CNR (17 ± 8.5 [SD]; range: 2-40) was significantly greater than that on s3D-FLAIR images (12 ± 6.3 [SD]; range: 3.2-29.8) (P < 0.01). Kappa value for inter-rater agreement for endolymphatic hydrops, vestibular atelectasis and perilymphatic fistula were 0.93 (95% CI: 0.74-1), 1 (95% CI: 0.85-1) and 1 (95% CI: 0.85-1) respectively.

CONCLUSION

This study demonstrates that the sensitivity of 3D-FLAIR sequences to low concentration gadolinium in the perilymphatic space is improved by elongation of the TR, with SIR and CNR increased by +34.4% and +41.3% respectively.

Optimal sequences and sequence parameters for GBCA-enhanced MRI of the glymphatic system: a systematic literature review

BACKGROUND

The glymphatic system (GS) is a recently discovered waste clearance system in the brain.

PURPOSE

To evaluate the most promising magnetic resonance imaging (MRI) sequence(s) and the most optimal sequence parameters for glymphatic MRI (gMRI) 4-24 h after administration of gadolinium-based contrast agent (GBCA).

MATERIAL AND METHODS

Multiple literature databases were systematically searched for articles regarding gMRI or MRI of the perilymph in the inner ear until 11 May 2020. All relevant MRI sequence parameters were tabulated for qualitative analysis. Their potential was assessed based on detection of low dose GBCA, primarily measured as signal intensity (SI) ratio.

RESULTS

Thirty articles were included in the analysis. Three-dimensional fluid attenuated inversion recovery (3D-FLAIR), 3D Real Inversion Recovery (3D-Real IR), and multiple 3D T1-weighted gradient echo sequences were used. In perilymph, 3D-FLAIR with a TE of at least 400 ms yielded the highest SIRs. In the qualitative analysis of inner ear studies using 3D-FLAIR, TR was in the range of 4400-10,000 ms, TI 1500-2600 ms, refocusing flip angle (rFA) (range 120°-180°), and echo train length (ETL) 23-173. In the gMRI studies, quantitative analysis was not possible. In the qualitative analysis, 3D-FLAIR was used in the majority (8/12) of the studies, usually with TR 4800-9000 ms, TI 1650-2500 ms, TE 311-561 ms, rFA 90°-120°, and ETL 167-278.

CONCLUSION

Long TE 3D-FLAIR is the most promising sequence for detection of low-dose GBCA in the GS. Clinical and/or phantom studies on other MRI parameters are needed for further optimization of gMRI.

Imaging of endolymphatic hydrops: A comprehensive update in primary and secondary hydropic ear disease

BACKGROUND

Since the first description by Hallpike and Cairns, the excess of endolymphatic fluid, also known as endolymphatic hydrops (EH), has been established as being the main biomarker in patients with Menière's disease. Recently, the concept of primary (PHED) and secondary hydropic ear disease (SHED) has been introduced. PHED corresponded to Menière's disease while SHED was defined as the presence of EH in patients with pre-existing inner ear disease.

OBJECTIVE

In this article, we would like to summarize the methodology of hydrops exploration using MRI and the previously published radiological findings in patients with PHED and SHED.

RESULTS

Before the emergence of delayed inner ear MRI, the presence of EH was assumed based on clinical symptoms. However, because of the recent technical developments, inner ear MRI became an important tool in clinical settings for identifying EH in vivo, in patients with PHED and SHED. The presence of EH on MRI is related with the degree of sensorineural hearing loss whether in patients with PHED or SHED. By contrast, in PHED or SHED patients without sensorineural hearing loss, MRI showed no sign of EH.

CONCLUSIONS

Thanks to the recent technical developments, inner ear MRI became an important tool in clinical settings for identifying EH in vivo, in patients with PHED and SHED.

High-Molecular-Weight Hyaluronic Acid Vehicle Can Deliver Gadolinium Into the Cochlea at a Higher Concentration for a Longer Duration: A 9.4-T Magnetic Resonance Imaging Study

Intratympanic (IT) gadolinium (Gd) injection is one method of delivering Gd into the inner ear to evaluate the amount of endolymphatic hydrops (EH) using magnetic resonance imaging (MRI). As Gd is usually prepared in a fluid form mixed with saline, Gd injected into the middle ear drains easily through the Eustachian tube within several hours. High-molecular-weight (hMW) hyaluronic acid (HA) is an ideal vehicle for IT Gd due to its viscous and adhesive properties. The present study was performed to elucidate whether novel hMW HA is superior to conventional HA in delivering Gd into the inner ear in the short term. The second aim was to verify the long-term Gd delivery efficiency of hMW HA compared to the standard-of-care vehicle (saline). IT Gd injection and 3D T1-weighted MRI were performed in 13 rats. For the short-term study (imaging after 1, 2, and 3 h), the left ear was treated with hMW HA+Gd and the right ear with conventional HA+Gd. For the long-term study (imaging after 1, 2, 3, and 4 h, 1 – 3 days, and 7 – 10 days), the left ear was treated with hMW HA+Gd and the right ear with saline+Gd. Signal intensities (SIs) in the scala tympani (ST) and scala vestibuli (SV) were quantified. Compared to conventional HA, signal enhancement was 2.3 – 2.4 times greater in the apical and middle turns after hMW HA+Gd injection (SV at 1 h). In comparison to the standard-of-care procedure, the SI was not only greater in the short term but the higher SI also lasted for a longer duration. On days 7 – 10 after IT Gd delivery, the SI in the basal turn was 1.9 – 2.1 times greater in hMW HA+Gd-treated ears than in saline IT Gd-treated ears. Overall, hMW HA may be a useful vehicle for more efficient IT Gd delivery. Gd enhancement in the cochlea improved approximately two-fold when hMW HA was used. In addition, this greater enhancement lasted for up to 7 – 10 days. Repeated MRI of EH may be possible for several days with a single IT hMW HA+Gd delivery.

Endolymphatic Hydrops in Patients With Intralabyrinthine Schwannomas

Purpose: The presence of endolymphatic hydrops (EH) in patients with intralabyrinthine schwannomas (ILSs) is poorly understood. This study aims to determine whether there is a correlation between endolymphatic hydrops and clinical presentations of ILS.

Methods: Data from nine patients with ILSs were retrospectively reviewed between 2007 and 2020. Temporal bone MRI with intratympanic or intravenous injection of gadolinium was applied to detect ILSs and EH.

Results: 3D real inversion recovery (IR) sequence MRI of the temporal bone confirmed ipsilateral EH in four patients (4/6). All four patients with EH on MRI presented with vertigo similar to Meniere's disease. Among these patients with EH, one patient with EH in the cochlea showed moderate sensorineural hearing loss, while three patients with EH in both the vestibule and cochlea showed profound hearing loss. MRI demonstrated a transmacular tumor (TMA) in one patient, intravestibular (IV) in four patients, and vestibulocochlear (VC) in four patients. Two IV cases showed moderated hearing loss, while the TMA and VC cases showed profound hearing loss. Transotic resection of the tumor was applied in five patients; translabyrinthine resection was applied in one patient; two patients were under observation; and one patient was given intratympanic injection of gentamicin (ITG). During follow-up, all of the treated patients reported relief of vertigo, and postoperative MRI was performed in two patients, which showed no tumor recurrence. The two patients under observation showed no deterioration of hearing loss or vertigo. One patient was lost to follow-up.

Conclusion: EH concurrent with ILSs has been underestimated previously. With the extensive application of temporal bone MRI paradigms, such as 3D-real IR sequence MRI, more cases of potential EH in patients with ILS will be identified. The severity of hearing loss may be associated with the location of the tumor and the degree of EH.

Comparison of Enhancement of the Vestibular Perilymph between Variable and Constant Flip Angle-Delayed 3D-FLAIR Sequences in Menière Disease

BACKGROUND AND PURPOSE

Endolymphatic hydrops in patients with Menière disease relies on delayed postcontrast 3D-FLAIR sequences. The purpose of this study was to compare the degree of perilymphatic enhancement and the detection rate of endolymphatic hydrops using constant and variable flip angles sequences.

MATERIALS AND METHODS

This was a retrospective study performed in 16 patients with Menière disease who underwent 3T MR imaging 4 hours after gadolinium injection using two 3D-FLAIR sequences with a constant flip angle at 140° for the first and a heavily-T2 variable flip angle for the second. The signal intensity ratio was measured using the ROI method. We graded endolymphatic hydrops and evaluated the cochlear blood-labyrinth barrier impairment.

RESULTS

Both for symptomatic and asymptomatic ears, the median signal intensity ratio was significantly higher with the constant flip angle than with the heavily-T2 variable flip angle (7.16 versus 1.54 and 7.00 versus 1.45, P < .001). Cochlear blood-labyrinth barrier impairment was observed in 4/18 symptomatic ears with the heavily-T2 variable flip angle versus 8/19 with constant flip angle sequences. With heavily-T2 variable flip angle sequences, endolymphatic hydrops was observed in 7-10/19 symptomatic ears versus 12/19 ears with constant flip angle sequences. We found a significant association between the clinical symptomatology and the presence of endolymphatic hydrops with constant flip angle but not with heavily-T2 variable flip angle sequences. Interreader agreement was always perfect with constant flip angle sequences while it was fair-to-moderate with heavily-T2 variable flip angle sequences.

CONCLUSIONS

3D-FLAIR constant flip angle sequences provide a higher signal intensity ratio and are superior to heavily-T2 variable flip angle sequences in reliably evaluating the cochlear blood-labyrinth barrier impairment and the endolymphatic space.