- 期刊
Strain Compounding: Improvement in Contour Extraction of Ultrasonic Breast Imaging
應變複合對於超音波乳房影像上輪廓圈選之改善
摘要
超音波影像是診斷乳房疾病的重要工具，但是醫師之主觀判斷亦影響了診斷結果。因此，利用電腦輔助診斷系統以客觀的提供影像資訊和進一步診斷腫瘤之良惡已逐漸受到重視。超音波乳房電腦輔助診斷系統核心技術之一為輪廓圈選，藉由輪廓圈選技術可得到腫瘤最重要的資訊如形狀、大小等。然而，超音波影像中不可避免的斑點雜訊，讓人無法清楚辨析組織的細微變化或是腫瘤之大小及邊界，進而影響了醫師判斷的正確度以及限制了輪廓圈選技術之準確性。有鑑於此，此研究便著手本實驗室已開發出的應變複合技術於乳房超音波影像上之應用，期盼複合影像能以其較佳的對比解析度，幫助後續的腫瘤輪廓圈選。應變複合法藉由對觀測物施予不同應力，造成觀測物有著不同之應變情況，再利用在各應變情況下取得之影像進行修正及平均以降低斑點雜訊，進而得到具有較佳對比解析度之影像。先期研究結果顯示，無論是模擬影像與臨床影像，經應變複合後，影像上之斑點雜訊已顯著降低。在本篇論文中，我們將更進一步對複合前後之模擬與臨床乳房影像做輪廓圈選之比較，結果亦證明了應變複合技術對輪廓圈選有所助益，換句話說，利用複合影像圈選出之腫瘤輪廓較接近實際情況，促使電腦自動化輪廓圈選甚至電腦輔助診斷技術之臨床實用性更往前推進一步。
並列摘要
Computer-aided diagnosis for breast diseases has gained wide interest. In ultrasound, the automatic diagnosis typically requires knowledge of the shape of a lesion, thus making contour extraction a critical step. Unfortunately, the speckle noise inherent in an ultrasonic image not only lowers the contrast resolution but also limits the accuracy of contour extraction. Thus, speckle noise reduction is desired prior to contour extraction. Contour extraction with a speckle noise reduction technique called strain compounding is presented in this paper. Strain compounding reduces speckle noise by incoherently combing partially correlated measurements of the same image object. Efficacy of speckle reduction using strain compounding has been demonstrated on both simulated and clinical images under different strain conditions. It was shown that speckle noise can be effectively reduced without significant degradation in spatial resolution. In this paper, we further demonstrate its ability to improve accuracy of contour extraction. Simulations and clinical images are both included and the improvement is also quantified and discussed.