Abstract
Quantification of blood flow using a 4D-DSA would be useful in the diagnosis and treatment of cerebrovascular diseases. A protocol optimizing identification of density variations in the time-density curves of a 4D-DSA has not been defined. Our purpose was to determine the contrast injection protocol most likely to result in the optimal pulsatility signal strength. Two 3D-printed patient-specific models were used and connected to a pulsatile pump and flow system, which delivered 250-260 mL/min to the model. Contrast medium (Isovue, 370 mg I/mL, 75% dilution) was injected through a 6F catheter positioned upstream from the inlet of the model. 4D-DSA acquisitions were performed for the following injection rates: 1.5, 2.0, 2.5, 3.0 and 3.5 mL/s for 8 seconds. To determine pulsatility, we analyzed the time-density curve at the inlets using the oscillation amplitude and a previously described numeric metric, the sideband ratio. Vascular geometry from 4D-DSA reconstructions was compared with ground truth and micro-CT measurements of the model. Dimensionless numbers that characterize hemodynamics, Reynolds and Craya-Curtet, were calculated for each injection rate. The strongest pulsatility signal occurred with the 2.5 mL/s injections. The largest oscillation amplitudes were found with 2.0- and 2.5-mL/s injections. Geometric accuracy was best preserved with injection rates of >1.5 mL/s. An injection rate of 2.5 mL/s provided the strongest pulsatility signal in the 4D-DSA time-density curve. Geometric accuracy was best preserved with injection rates above 1.5 mL/s. These results may be useful in future in vivo studies of blood flow quantification.
Highlights
BACKGROUND AND PURPOSEQuantification of blood flow using a 4D-DSA would be useful in the diagnosis and treatment of cerebrovascular diseases
After the discovery of DSA by Mistretta et al in the 1970s, almost immediately, investigators began to use the density of a contrast bolus, as it passed between 2 points, to determine the velocity of blood flow
Using 2 patient-specific 3D printed vascular models and a closed-loop pulsatile flow system, we demonstrated that the pulsatility signal strength in time-density curves (TDCs) from
Summary
Two 3D-printed patient-specific models were used and connected to a pulsatile pump and flow system, which delivered 250–260 mL/min to the model. Contrast medium (Isovue, 370 mg I/mL, 75% dilution) was injected through a 6F catheter positioned upstream from the inlet of the model. Details of the 3D printing protocol were recently described by Ruedinger et al.10 Both models included the ICA and M1 and A1 segments of the MCA and the anterior cerebral artery. Contrast medium was injected through a catheter (6F, Penumbra 5MAX ACE; Penumbra, Alameda, California), which was inserted through an introducer sheath positioned upstream from the ICA inlet. A bypass loop was used to simulate the systemic circulation so that the average flow delivered to the model inlet (ICA) was between 250 and 260 mL/min. Flow rates were measured using an ultrasonic flow probe (16PXLMS25; Transonic, Ithaca, New York)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
