U.S. flag An official website of the United States government

U.S. Food and Drug Administration

3D Printing Strategies to Obtain Optically Clear Cardiovascular Anatomical Geometries for Flow Characterization

Catalog of Regulatory Science Tools to Help Assess New Medical Devices 

This regulatory science tool (RST) is a how-to guide which demonstrates the design and manufacture of transparent cardiovascular anatomical models with optical access for visualization and measurement of fluid flow (ex. blood flow) using additive manufacturing techniques (3D printing).  

Technical Description

This RST’s user manual consists of a series of design, printing, and post-processing steps that, when applied, yield a 3D printed anatomical model with enough optical clarity to allow for imaging, flow visualization, and laser-based velocity field measurement techniques, such as particle image velocimetry (PIV), as well as enhanced visual access for device inspection. The anatomical model can be used to capture blood flow pattern, velocity field, and identify regions of high shear and low flow to study risk of blood damage.

Intended Purpose 

This tool describes design, 3D printing, and polishing steps for anatomical phantoms intended for optical measurement techniques. Product areas studied with this tool include, but are not limited to:

  • Endovascular devices (e.g. vascular stents, coils, flow diverters, etc.)
    • Example ProCodes: MAF, NIM, NIN, NIO, NIP, PNF, OUT
  • Endovascular device deployment modeling tools (e.g. surgical planning software, device sizing software, etc.)
    • Example ProCodes: PZO, QQI
  • Cardiovascular simulation software devices (e.g. image-based diagnostic devices)
    • Example ProCodes: QEK, PJA, LLZ, QHA
  • Hemodialysis
    • Example ProCodes: FIH, FID, NIF, 
  • Circulatory Assist Devices (blood pumps) and Oxygenators
    • Example ProCodes: PCK, OJE, OKR, BYS, DTZ
  • Heart Valves and Repair Devices
    • Example ProCodes: LWQ, LWR, NKM

The intended users of this tool will be in non-clinical, bench testing laboratories seeking to perform flow velocity measurement (particle image velocimetry, laser doppler velocimetry, flow visualization video capture) or medical device placement examination (i.e. stent or flow diverter placement). The user is likely already performing tests in experimental flow loops and may be able to use this tool to increase the quality of or reduce the time and expense of their experiments. 

Testing

The majority of the testing is covered in Aycock et al. (2017) [1]. These techniques were applied to produce physiologically realistic vascular models, including aortic and coronary artery geometries, among others.

Limitations

  • The print materials referenced in this RST were not evaluated for biocompatibility in the studies supporting this tool. In all experiments described, these materials were used with water or blood analog fluids only.
  • The printers and print materials used in this RST produce functionally rigid components. For some applications in which replicating the structural compliance of blood vessels is important, a compliant physical phantom may be desirable. As of the date of publication, no 3D print materials evaluated in this work demonstrated both the optical characteristics described herein and structural compliance comparable to that of a blood vessel wall.
  • The spatial resolution offered by the 3D printers featured in this tool supported imaging of the cardiovascular anatomical models evaluated in this work. However, these printers and the other methods described are likely not suitable for the smallest vessels or other micro-scale applications. For these cases other manufacturing techniques are likely more suitable. 
  • Additional technical limitations are listed in the user manual.

Supporting Documentation

In the attached User Manual is a set of instructions for 3D printing an optically clear anatomical model. These instructions assume the user has produced or otherwise obtained the desired model geometry.  As reference, the geometry for the inferior vena cava bifurcation model is available to download here. 

  1. Aycock, K. I., Hariharan, P. & Craven, B. A. Particle image velocimetry measurements in an anatomical vascular model fabricated using inkjet 3D printing. Exp Fluids 58, 154 (2017). https://doi.org/10.1007/s00348-017-2403-1
  2. U.S. Food and Drug Administration. (2023). Benchmark Validation Dataset for Laminar Flow in an Anatomical Vascular Model of the Inferior Vena Cava (RST24CV16.01). https://cdrh-rst.fda.gov/benchmark-validation-dataset-laminar-flow-anatomical-vascular-model-inferior-vena-cava

Contact

Tool Reference