Program Information
In Vitro Comparison of Flow Resistance WithFractional Flow Reserve (FFR) in Patient-Specific 3D Printed Cardiovascular Phantoms Used for CT- Derived FFR Validation
C Ionita1*, E Angel2 , L Shepard1 , K Sommer1 , R Izzo1 , D Mitsouras3 , S Rudin1 , (1) University at Buffalo, Buffalo, NY, (2) Toshiba America Medical Systems, Inc, Tustin, CA, (3) Brigham and Women's Hospital, Boston, MA,
Presentations
TU-H-CAMPUS-IT-3 (Tuesday, August 1, 2017) 4:30 PM - 5:30 PM Room: Imaging ePoster Theater
Purpose: In the field of cardiology, non-invasive fractional flow reserve derived from coronary CT angiography (CT- derived FFR) is an intense researched topic and a quickly expanding field of study. 3D-printed patient-specific coronary phantoms could be used to validate such software. We are investigating flow resistance in such phantoms and comparing it with the measured Fractional Flow Reserve for a wide range of induced stenoses in the same coronary tree.
Methods: Coronary CT angiograms of two patients with no coronary artery disease or calcifications of the coronaries were acquired using a 320-detector row CT (Aquilion ONE, Toshiba). The volumes were used to generate patient-specific 3D printed phantoms of the patients. Models were 3D-printed (Objet Connex3, Stratasys USA) using an elastic material (Tango+) which roughly mimics the compliance of the arterial wall. The phantoms were connected to a flow loop to simulate blood flow. A flow meter and pressure sensors were mounted on the phantom to estimate flow velocity and pressure values before and after an artificially induced stenosis. Various stenosis grades were simulated by attaching a precise adjustable clamp. Five stenosis grades varying between 25% and 85% were simulated. Flow resistance was measured as pressure difference (dynes/cm^2) divided by flow rate (cm^3/s). FFR was measured as the ratio of the distal over the proximal pressure.
Results: Flow resistance varied asymptotically as a function of the stenosis grade; the resistance increased about forty times when the stenosis grade increased from 25% to 85%. FFR behavior was similar with values of 0.98 for the 25% stenosis and 0.64 for the 85% stenosis. FFR depended linearly on the flow resistance (R^2 value of 0.98).
Conclusion: 3D printed patient-specific cardiac phantoms offer a precise way to investigate physical flow conditions and the validity of clinically reported physiological markers.
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