Purpose: To determine the velocity of contrast media in a 3D printed aneurysm model using high speed angiographic (HSA) imaging.
Methods: An iodine contrast agent was injected into a 3-D printed aneurysm model containing circulating fluid pumped to emulate the cyclic blood pressure in vessels. A CdTe-based single-photon-counting detector (Actaeon by Xcounter) with resolution of 100 um pixels recorded sequences at 1000 frames per second. The velocity of iodine contrast agent in various parts of the model was calculated from the distance traveled by contrast media blobs between two frames temporally separated by 1 ms intervals. The blobs were visually tracked and coordinates were determined so that the Euclidean distance between the same blob in the image pair could be measured. Within the aneurysm, the angular displacements of blobs were calculated at intervals of 3 ms and 5 ms, and the linear velocity was calculated.
Results: Before the beginning of the recorded sequence, there is pulsatile water flow through the phantom. At the start of the pump cycle, the contrast velocity ranged from 38-41 cm/s and then increased to 48-52 cm/s. When the aneurysm started filling with contrast medium, the flow velocity at the outflow segment remained 46-54 cm/s. As the aneurysm gets denser and less contrast and fluid flowed into the aneurysm, the velocity of the blobs in the outflow segment increased to 63-68 cm/s. The linear velocities of the blobs within the aneurysm itself were lower, 35 to 37 cm/s just prior to the start of the recorded sequence, and increased to 48-53 cm/s until the aneurysm became opaque. Then the velocity decreased to 19-27 cm/s.
Conclusion: The Actaeon detector with its high spatial and temporal resolution enabled measurement of detailed complex velocity distributions and their variation during the pumping cycle in a vascular aneurysm phantom.
Funding Support, Disclosures, and Conflict of Interest: This research was supported in part by Canon Medical Systems
Flow Velocity, Flow Imaging, High-resolution Imaging