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作者 : Michael E. Zalis*, James Perumpillichira, Peter F. Hahn 出處 :

Digital Subtraction Bowel Cleansing for CT Colonography Using Morphological and Linear Filtration Methods. 作者 : Michael E. Zalis*, James Perumpillichira, Peter F. Hahn 出處 : IEEE TRANSACTIONS ON MEDICAL IMAGING VOL. 23, NO. 11, NOVEMBER 2004 pp.1335-1343 學生 : 林上智 指導老師 : 張顧耀. Outline.

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作者 : Michael E. Zalis*, James Perumpillichira, Peter F. Hahn 出處 :

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  1. Digital Subtraction Bowel Cleansing for CT Colonography Using Morphological and Linear Filtration Methods 作者: Michael E. Zalis*, James Perumpillichira, Peter F. Hahn 出處: IEEE TRANSACTIONS ON MEDICAL IMAGINGVOL. 23, NO. 11, NOVEMBER 2004 pp.1335-1343 學生:林上智 指導老師:張顧耀

  2. Outline • Introduction • Methods • Experiment • Conclusions

  3. Introduction(1/3) • First description in 1994 • Computed Tomography Colonography • What is CTC? • Noninvasive • Consist of Low X ray does CT • Preparation • Cleansing colon • Air insufflation

  4. Introduction(3/3) • Traditional • Patients undergo a rigorous purgation cleansing of the colon • Feeling • Discomfort and inconvenience • Digital Subtraction Bowel Cleansing(DSBC) • Not require to • take any bowel cathartic • change eating habits

  5. Hounsfield Unit(1/2) • Definition • X Ray attenuation unit used in CT Scan interpretation • Characterizes the relative density of a substance • Each pixel is assigned a value between -1k to 1k

  6. Hounsfield Unit(2/2) • Substance densities in Hounsfield Units • Air: -1000 • Fat: -50 • Water: 0 • Soft tissue such as muscle: +40 • Calculus: +100 to +400 • Bone: +1000

  7. Outline • Introduction • Methods • Experiment • Conclusions

  8. Threshold • 來源:灰階圖片 • 作法:影像依其灰階予以分群處理，灰階分劃將影像分成兩種灰階值,設定 • >= ,保留點, 設成 1 • < ,移除點, 設成 0 • 目的: • 處理的主體和不需要存在的背景分離 (雜訊 ) • 圖形邊緣處會有明顯不連續的現象

  9. Artifact

  10. Morphology • Dilation • Erosion

  11. Artifact

  12. Outline • Introduction • Methods • Experiment • Conclusions

  13. Phantom • Colon phantom • specifically designed to resemble the human colon in terms of • CT density • colon contour

  14. Exam • The approach is • Use DSBC ,dilation, detection algorithm • CT • Range • From • Soft tissue of the colon wall • To • Colon lumen

  15. Exam 1

  16. Exam 1

  17. Exam 2

  18. Exam 2

  19. Exam 3

  20. Exam 3

  21. Outline • Introduction • Method • Experiment • Conclusions

  22. Conclusion • DSBC offers the possibility of improving patient comfort for colon. • Compared to traditionally cleansed datasets in human subjects ,readers rated electronically cleansed exams favorably.

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