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Những phát triển trong siêu âm tim mạch: Phần 1: Xử lý tín hiệu và thiết bị
Tóm tắt
Một trong những đóng góp chính cho sự cải thiện các thiết bị siêu âm Doppler quang phổ và màu là sự phát triển của các kỹ thuật xử lý tín hiệu tiên tiến, điều này trở nên khả thi nhờ vào sức mạnh tính toán ngày càng tăng. Các ước lượng quang phổ dựa trên mô hình hoặc tham số, các biến đổi theo thời gian-tần số, các thuật toán định trạng thái và các kỹ thuật sửa chữa chiều rộng quang phổ đã được nghiên cứu như những cải tiến có thể thực hiện cho các ước lượng dựa trên FFT hiện đang được sử dụng cho việc ước lượng quang phổ thời gian thực của các tín hiệu Doppler. Trong hình ảnh dòng màu, một số cải tiến về độ chính xác của ước lượng vận tốc đã đạt được nhờ vào việc sử dụng các thuật toán mới nhưng với chi phí là sự gia tăng độ phức tạp tính toán so với phương pháp tự tương quan thông thường. Các bộ lọc đa thức đã được chứng minh có một số lợi thế hơn các bộ lọc IIR trong việc triệt tiêu tiếng vang tĩnh. Nhiều phương pháp ước lượng vector vận tốc để khắc phục vấn đề phụ thuộc góc đã được nghiên cứu, bao gồm theo dõi đặc trưng 2D, phương pháp hai và ba chùm tia, và việc sử dụng chiều rộng quang phổ bên cạnh tần số trung bình. Việc thu thập và hiển thị dữ liệu 3D và hình ảnh sức mạnh Doppler cũng đã được nghiên cứu. Việc sử dụng hình ảnh hài, sử dụng hài số hai được tạo ra bởi các phương tiện tương phản bọt đúc, có vẻ hứa hẹn đặc biệt là cho việc hình ảnh dòng chậm. Việc thu thập dữ liệu hình ảnh song song sử dụng quét không theo trình tự hoặc truyền chùm rộng, tiếp theo là việc tiếp nhận đồng thời dọc theo một số chùm tia, đã được nghiên cứu để thúc đẩy hình ảnh 'thời gian thực'.
Từ khóa
#siêu âm tim mạch #xử lý tín hiệu #thiết bị siêu âm #quang phổ Doppler #hình ảnh dòng màu #ước lượng vận tốc #triệt tiêu tiếng vang #dữ liệu 3D #hình ảnh sức mạnh DopplerTài liệu tham khảo
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