Intracranial Distribution of Intravenously Administered Gadolinium-based Contrast Agent over a Period of 24 Hours: Evaluation with 3D-real IR Imaging and MR Fingerprinting.

PURPOSE: To evaluate the feasibility for the detection of slight contrast effects after intravenous administration of single dose gadolinium-based contrast agent (IV-SD-GBCA), the time course of the GBCA distribution up to 24 h was examined in various fluid spaces and brain parenchyma using 3D-real IR imaging and MR fingerprinting (MRF). METHODS: Twenty-four patients with a suspicion of endolymphatic hydrops were scanned at pre-administration and at 10 min, 4 and 24 h post-IV-SD-GBCA. 3D-real IR images and MRF at the level of the internal auditory canal were obtained. The signal intensity on the 3D-real IR image of the cerebrospinal fluid (CSF) in the cerebellopontine angle cistern (CPA), Sylvian fissure (Syl), lateral ventricle (LV), and cochlear perilymph (CPL) was measured. The T1 and T2 values of cerebellar gray (GM) and white matter (WM) were measured using MRF. Each averaged value at the various time points was compared using an analysis of variance. RESULTS: The signal intensity on the 3D-real IR image in each CSF region peaked at 4 h, and was decreased significantly by 24 h (P< 0.05). All patients had a maximum signal intensity at 4 h in the CPA, and Syl. The mean CPL signal intensity peaked at 4 h and decreased significantly by 24 h (P < 0.05). All patients but two had a maximum signal intensity at 4 h. Regarding the T1 value in the cerebellar WM and GM, the T1 value at 10 min post-IV-GBCA was significantly decreased compared to the pre-contrast scan, but no significant difference was observed at the other time points. There was no significant change in T2 in the gray or white matter at any of the time points. CONCLUSION: Time course of GBCA after IV-SD-GBCA could be evaluated by 3D-real IR imaging in CSF spaces and in the brain by MRF.

Communication between cochlear perilymph and cerebrospinal fluid through the cochlear modiolus visualized after intratympanic administration of Gd-DTPA.

PURPOSE: Intratympanic injection of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) has been reported as a procedure to visualize endolymphatic hydrops of Meniere's disease. We frequently noted that cerebrospinal fluid (CSF) in the internal auditory canal (IAC) was also enhanced after this procedure. The purpose of this study was to evaluate how frequently this occurs and to investigate the specific features of patients who lack this communication. MATERIALS AND METHODS: A total of 25 patients with clinically suspected endolymphatic hydrops underwent the procedure. After 24 h, three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) and 3D constructive interference in steady state (3D-CISS) were performed. The presence of contrast enhancement in the CSF space of the fundus of the IAC was evaluated. RESULTS: The contrast ratio between CSF of the IAC fundus and cerebellar white matter on the injected side was 1.49 +/- 0.65, and that of the noninjected side was 0.32 +/- 0.16 (P < 0.01). Enhancement of the CSF space in the IAC fundus was seen in all but two subjects: one had enlarged endolymphatic duct and sac syndrome (EEDS), and the other had cochlear nerve agenesis. In these two patients, the cochlear modiolus seemed to be normal. CONCLUSION: Intratympanic Gd-DTPA administration can reveal permeability of the modiolus and might facilitate evaluation of functional abnormalities of the modiolus not detected by conventional imaging tests.