Respiratory-synchronized digital subtraction angiography based on a respiratory phase matching method

Abstract

Catheter-based therapy is typically performed under fluoroscopic image observation. However, the vessel structure cannot be visualized on fluoroscopic images. To overcome this limitation, angiographic images are captured with a contrast agent, and digital subtraction angiography (DSA) images are acquired during the intervention. In thoracoabdominal DSA, patients have to hold their breath to match the respiratory phase during DSA acquisition. However, breath holding is difficult for some patients, including the elderly. If the organs move during DSA acquisition, artifacts can occur on DSA images, and the DSA acquisition must be performed again. In the present study, we describe and characterize a new respiratory phase matching method for respiratory-synchronized DSA acquisition under natural respiration. Preoperative angiographic and intra-operative fluoroscopic images were collected under natural respiration during the operation. For each fluoroscopic image, we used a pattern matching to select an angiographic image in the most similar respiratory phase. We then examined whether the method could be applied to both the free breathing DSA and the respiratory-synchronized roadmap. We found that our proposed respiratory phase matching method produced acceptable DSA images without breath holding, and that the processing could be performed in real time. B Takashi Ohnishi

Phase-Based Nonrigid Deformation for Digital Subtraction Angiography

“…A method designed for accurate optic flow estimation [3] is also included, which presents a highly competitive performance, particularly for occlusion detection. Other recent methods [23], [27] are excluded since they only accept images from special devices such as dual energy X-ray or respiratory phase matching, which is not comparable to our method dealing with common images from generic hardware.…”

“…However, they inherently suffer from low contrast of the resulting DSA due to the insufficient energy gap between vessels and background tissues. A recent method [27] introduced respiratory synchronization to implement fast and accurate compensation for a real-time solution, but it has difficulty dealing with motions stemming from unintended factors, such as heartbeat or bowel movement. Moreover, those methods require special hardware to generate fast kV switching or to match the respiratory phase of the patient and thus are not applicable to the general DSA system.…”