Related Experiment Video
Updated: Oct 10, 2026
In Vivo Tracking of Edema Development and Microvascular Pathology in a Model of Experimental Cerebral Malaria Using Magnetic Resonance Imaging
Published on: June 8, 2017
Enabling unenhanced endolymphatic hydrops MRI: a subtraction method using 3D-FLAIR sequences with different inversion
Menglong Zhao1, Kai Liu1, Huaili Jiang2
1Department of Radiology, Zhongshan Hospital, Fudan University, and Shanghai Institute of Medical Imaging, Shanghai, China.
Objectives:
To evaluate an unenhanced three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) sequence using a long repetition time (TR) and constant flip angle (CFA) in differentiating between the perilymph and endolymph in a volunteer study, and unenhanced endolymphatic hydrops (EH) evaluation using subtraction images of the 3D-FLAIR with two inversion times (TI) in a patient study.
Materials And Methods:
In the volunteer study, unenhanced 3D-FLAIR using different TI were acquired from 10 healthy volunteers. Signal intensities (SIs) of the endolymph and perilymph were measured. In the patient study, the unenhanced 3D-FLAIR using two TI were acquired for subtraction of 202 patients, and compared with the enhanced 3D-FLAIR and three-dimensional inversion-recovery with real reconstruction (3D-real IR) sequences.
Results:
In the volunteer study, the endolymphatic and perilymphatic signals exhibited distinct trends on 3D-FLAIR images as TI increased. There were apparent differences in SIs between them at some TI. In the patient study, unenhanced subtraction images similar to enhanced 3D-real IR were acquired. They had a lower image quality score (p < 0.001) but a higher signal-to-noise ratio (p < 0.001) than enhanced sequences. Contrast-to-noise ratio of them was lower than that of 3D-FLAIR (p < 0.001), but higher than that of 3D-real IR (p < 0.001). Using any two of the three images, excellent agreement could be found in EH grading.
Conclusion:
The endolymph and perilymph could be distinguished by this unenhanced 3D-FLAIR. Subtraction-based unenhanced MR imaging for EH evaluation provided high image quality and showed excellent agreement with the contrast-enhanced sequences.
Key Points:
Question Using previous single 3D-FLAIR sequence with long TR and CFA for unenhanced endolymphatic hydrops (EH) imaging, some patients were overrated due to the insufficient contrast. Findings Unenhanced subtraction images were applied to EH imaging with satisfactory quality. Between using them and two enhanced sequences, excellent agreement was found in EH evaluation. Clinical relevance Subtraction using the long TR and CFA three-dimensional fluid-attenuated inversion recovery sequences with two different inversion time holds significant value for unenhanced EH MRI.
