Chaoqun Zhou, Sharon J Feng, Stephen Leong, Eugénie Breil, François Voruz, Chris Valentini, Daniella R Hammer, Aykut Aksit, Elizabeth S Olson, Jia Guo, Jeffrey W Kysar, Anil K Lalwani
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引用次数: 0
Abstract
Rationale and objectives: The potential of contrast-enhanced MRI for diagnosing endolymphatic hydrops is limited by long wait times following intravenous (IV) or intratympanic (IT) delivery, high contrast dosages, and inconsistent signal intensity enhancements. This study investigates microneedle-mediated intracochlear (IC) gadodiamide injection for consistent and efficient contrast delivery with minimal contrast dosage.
Materials and methods: A 100 µm diameter microneedle with 35 µm lumen was used to inject 1 µL of diluted gadodiamide (17.4 mM) into a guinea pig cochlea via the round window membrane. Serial MRI imaging was performed in a post-mortem animal using a 9.4 T small-animal MRI. Maximum intensity projections of MRI scans were generated to visualize diffusion of contrast within cochlea over time; mean intensities in defined regions of interest (ROIs) were calculated. Contrast diffusion time and intensity enhancements were determined.
Results: Contrast was observed in the basal turn of scala tympani (ST) and scala vestibuli (SV) in the first MRI scan for all subjects which was acquired as early as 35 min after injection. Two-tailed paired t-tests confirmed that contrast reached the first two turns of ST and SV within 60 min, and the second half of third turns and apical turns of ST and SV within 90 min (p < 0.05). Intensity enhancements, defined as the percentage increase of the ROI mean intensity in the injection side compared to the contralateral side, exceeded 100% in the first turn and ranged from 12% to 32% in the third and apical turns of ST and SV at 90 min after injection.
Conclusions: IC gadodiamide enables controllable and efficient contrast delivery with significantly lower contrast dosage, making it a viable alternative for contrast-enhanced cochlear MRI.
期刊介绍：
Academic Radiology publishes original reports of clinical and laboratory investigations in diagnostic imaging, the diagnostic use of radioactive isotopes, computed tomography, positron emission tomography, magnetic resonance imaging, ultrasound, digital subtraction angiography, image-guided interventions and related techniques. It also includes brief technical reports describing original observations, techniques, and instrumental developments; state-of-the-art reports on clinical issues, new technology and other topics of current medical importance; meta-analyses; scientific studies and opinions on radiologic education; and letters to the Editor.
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