{
    "abstract": "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.\nA 100\u00a0\u00b5m diameter microneedle with 35\u00a0\u00b5m lumen was used to inject 1\u00a0\u00b5L of diluted gadodiamide (17.4\u00a0mM) into a guinea pig cochlea via the round window membrane. Serial MRI imaging was performed in a post-mortem animal using a 9.4\u00a0T 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.\nContrast 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\u00a0min after injection. Two-tailed paired t-tests confirmed that contrast reached the first two turns of ST and SV within 60\u00a0min, and the second half of third turns and apical turns of ST and SV within 90\u00a0min (p\u00a0<\u00a00.05). 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\u00a0min after injection.\nIC gadodiamide enables controllable and efficient contrast delivery with significantly lower contrast dosage, making it a viable alternative for contrast-enhanced cochlear MRI.",
    "authors": [
        {
            "affiliation": "Department of Mechanical Engineering, Columbia University, New York, NY.",
            "firstname": "Chaoqun",
            "initials": "C",
            "lastname": "Zhou"
        },
        {
            "affiliation": "Columbia University Vagelos College of Physicians and Surgeons, New York, NY; Department of Otolaryngology - Head and Neck Surgery, Columbia University, New York, NY.",
            "firstname": "Sharon J",
            "initials": "SJ",
            "lastname": "Feng"
        },
        {
            "affiliation": "Columbia University Vagelos College of Physicians and Surgeons, New York, NY; Department of Otolaryngology - Head and Neck Surgery, Columbia University, New York, NY; Department of Otolaryngology - Head & Neck Surgery, University of Washington, Seattle, WA.",
            "firstname": "Stephen",
            "initials": "S",
            "lastname": "Leong"
        },
        {
            "affiliation": "Department of Otolaryngology - Head and Neck Surgery, Columbia University, New York, NY.",
            "firstname": "Eug\u00e9nie",
            "initials": "E",
            "lastname": "Breil"
        },
        {
            "affiliation": "Department of Otolaryngology - Head and Neck Surgery, Columbia University, New York, NY.",
            "firstname": "Fran\u00e7ois",
            "initials": "F",
            "lastname": "Voruz"
        },
        {
            "affiliation": "Columbia University Vagelos College of Physicians and Surgeons, New York, NY; Department of Otolaryngology - Head & Neck Surgery, Thomas Jefferson University, Philadelphia, PA.",
            "firstname": "Chris",
            "initials": "C",
            "lastname": "Valentini"
        },
        {
            "affiliation": "Department of Mechanical Engineering, Columbia University, New York, NY.",
            "firstname": "Daniella R",
            "initials": "DR",
            "lastname": "Hammer"
        },
        {
            "affiliation": "Department of Mechanical Engineering, Columbia University, New York, NY.",
            "firstname": "Aykut",
            "initials": "A",
            "lastname": "Aksit"
        },
        {
            "affiliation": "Department of Otolaryngology - Head and Neck Surgery, Columbia University, New York, NY; Department of Biomedical Engineering, Columbia University, New York, NY.",
            "firstname": "Elizabeth S",
            "initials": "ES",
            "lastname": "Olson"
        },
        {
            "affiliation": "Department of Psychiatry & The Zuckerman Institute, Columbia University, New York, NY. Electronic address: jg3400@columbia.edu.",
            "firstname": "Jia",
            "initials": "J",
            "lastname": "Guo"
        },
        {
            "affiliation": "Department of Mechanical Engineering, Columbia University, New York, NY; Department of Otolaryngology - Head and Neck Surgery, Columbia University, New York, NY.",
            "firstname": "Jeffrey W",
            "initials": "JW",
            "lastname": "Kysar"
        },
        {
            "affiliation": "Department of Mechanical Engineering, Columbia University, New York, NY; Columbia University Vagelos College of Physicians and Surgeons, New York, NY; Department of Otolaryngology - Head and Neck Surgery, Columbia University, New York, NY.",
            "firstname": "Anil K",
            "initials": "AK",
            "lastname": "Lalwani"
        }
    ],
    "conclusions": null,
    "copyrights": "Copyright \u00a9 2025. Published by Elsevier Inc.",
    "doi": "10.1016/j.acra.2024.10.022",
    "journal": "Academic radiology",
    "keywords": [
        "Contrast-enhanced magnetic resonance imaging",
        "Endolymphatic hydrops",
        "Intracochlear delivery",
        "Microneedle",
        "Round window membrane"
    ],
    "methods": null,
    "publication_date": "2024-11-06",
    "pubmed_id": "39500641",
    "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\u00a0min after injection. Two-tailed paired t-tests confirmed that contrast reached the first two turns of ST and SV within 60\u00a0min, and the second half of third turns and apical turns of ST and SV within 90\u00a0min (p\u00a0<\u00a00.05). 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\u00a0min after injection.",
    "title": "Contrast Enhancement of Cochlea after Direct Microneedle Intracochlear Injection of Gadodiamide through the Round Window Membrane with Minimal Dosage.",
    "xml": "<Element 'PubmedArticle' at 0x788506694680>"
}