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In Vivo Longitudinal Quantification of Radiopacity of a Nanoparticle-Infused Biodegradable Inferior Vena Cava Filter in a Porcine Model

J Perez1*, J Damasco1, M Jacobsen2, A Melancon3, M Eggers4, S Huang1, R Layman2, M Melancon1, (1) Department of Interventional Radiology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030, (2) Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030, (3) Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030, (4) Adient Medical Inc., 12234 Shadow Creek Parkway, Building 8, Suite 106, Pearland, TX 77584

Presentations

(Thursday, 7/16/2020) 2:00 PM - 3:00 PM [Eastern Time (GMT-4)]

Room: Track 1

Purpose: Absorbable inferior vena cava filters (IVCFs) are promising alternatives to metallic retrievable filters for preventing pulmonary embolism because they circumvent filter retrieval and its associated complications. However, clinical integration has been difficult due to its radiolucency, making filter deployment and follow-up monitoring challenging.

Methods: An IVCF based on poly-p-dioxanone sutures (Adient Medical Technologies) was infused with ultrasmall bismuth nanoparticles (BiNP) and implanted in an adult domestic pig. Imaging was performed post-implantation at different time points using a Siemens SOMATOM Definition Edge scanner (120Sn kVp). Volumes-of-interest incorporating the IVCF were placed using 3D Slicer (Brigham and Women’s Hospital, Boston, MA) and maximum signal was measured. Additionally, different concentrations of bismuth solution were imaged using a body phantom for calibration studies. The actual BiNP concentration of a non-implanted IVCF was measured with inductively coupled plasma mass spectrometry (ICP-MS) to confirm the calibrations.

Results: Infusion of BiNP resulted in significant increase in radiopacity, allowing visualization with fluoroscopy during deployment with decreasing CT intensity over time. Quantification revealed a one-phase decay pattern of CT number as the IVCF degraded, with a signal half-life of 2.97 weeks. However, calculated BiNP concentration did not correspond to concentration measured by ICP-MS. The small diameter of the sutures (0.35 mm) with respect to the resolution of the scanner (0.6 mm) may be causing volume averaging, resulting in underestimation of the BiNP concentration.

Conclusion: We have developed a biodegradable BiNP-IVCF with significantly improved visualization on both fluoroscopy and CT imaging. The degradation trend can be assessed longitudinally in vivo; however, complexities in quantification methods necessitates further investigation. This work could potentially improve widespread clinical integration of radiopaque biodegradable medical devices where technical success, possible complications, and device integrity can be assessed in real-time intraoperatively and post-operatively by noninvasive clinical imaging modalities.

Keywords

Contrast Agent, Quantitative Imaging, CT

Taxonomy

IM- CT: Nanoparticle imaging

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