Feasibility of Few-View Projection Tomosynthesis for Four-Dimensional Angiography

Interventional radiology (IR) is a well-known di-agnostic technique and therapeutic modality used for a wide variety of vascular diseases related to the brain and heart. Three-dimensional (3D) information about the anatomical structure is essential for IR, but it is difficult to acquire volumetric data using conventional fluoroscopic systems. We have been developing the few-view projection tomosynthesis system, which can acquire volumetric data through image reconstruction using four projection images acquired from limited angles. Using four small, fixed X-ray tubes in this system, the projection images can be acquired within a short scan time, and image reconstruction can be performed. It may be possible for the few-view projection tomosynthesis to acquire a four-dimensional (4D) image with volumetric data showing how the contrast medium flows in blood vessels. In this study, we evaluated the feasibility of few-view projection tomosynthesis for 4D angiography.The digital phantom assuming the contrast medium flows in the cerebral blood vessel at the mean velocity was created from a magnetic resonance angiography image distributed by the MIDAS data server. The projection images of this phantom were acquired using four small, fixed X-ray tubes, and the imaging frame rate was 30 frames per second. To reconstruct the 4D images, the first reconstructed frame requires four new projections. The second and subsequent reconstructed frames only require one new projection, and these frames can be reconstructed using this projection and the other three previously acquired ones.The 4D images were acquired using the few-view projection tomosynthesis system, and the contrast medium flows in cerebral blood vessels was observed in 3D. It was suggested that it is feasible to reconstruct 4D angiography so that a doctor can observe the contrast medium flow while an operation process.