A Post-Processing Technique to Remove Extra-Cerebral Signals from Three-Dimensional Time-of-Flight MR Brain Images

三維飛行時間 (three-dimensional time-of-flight) 磁振血管造影技術廣泛地應用在腦血管疾病的診斷。由於脂肪的T1值比較小，磁矩恢復的比較快，所以在原始影像上的訊號偏高。在最大訊號投影法所產生的影像上，脂肪的訊號會導致血管與背景的對比降低，甚至於遮蓋住血管的結構。籍由脂肪與腦部生理組織之間存在著無訊號的骨髂作分界，我們提出了一個自動化的影像後處理技術，應用自動閥值、侵蝕及擴張、區域增長等技術，將骨髂外面的訊號去除，只保留腦部區域的訊號，如此可在投影後的影像中，顯示較佳的血管結構。此一技術比較適用於大腦上端所取得的影像，因為此處骨髂所形成的邊界比較簡單。

關鍵字

磁振造影；磁振血管攝影；最大訊號投影；影像後處理

並列摘要

Three-dimensional time-of-flight MR angiography is routinely used for detecting cerebral vascular disorders in clinical practice. This technique is inherited with high signals of subcutaneous and bone-marrow fat tissues, and they can contaminate the visual perception of vascular structures on the maximum intensity projected views. Because cortical bones have low signals on three-dimensional time-of-flight MR images, the inner table of a skull bone can serve as a natural anatomical boundary between the brain surface and skull bone. This study presents an automatic post-processing technique based on automatic thresholding, morphological operation, and region growing techniques to extract the brain pixels using this boundary. The subsequent maximum intensity projections of brain pixels achieve a better display of cerebral vascular structures. This technique is mostly useful for imaging slices covering the upper cerebral hemisphere, where bone structure forms a good brain boundary.

並列關鍵字

magnetic resonance imaging ； magnetic resonance angiography ； time-of-flight ； maximum intensity projection ； image processing

國際替代計量

A Post-Processing Technique to Remove Extra-Cerebral Signals from Three-Dimensional Time-of-Flight MR Brain Images

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