Medical audit of screening mammography – performing and interpreting 陳勁宇 醫師 Chin-Yu Chen, M.D., M.S. 奇美醫學中心 影像醫學部 Department of Radiology, Chi-Mei Medical Center
What is medical audit? Follow-up and outcome monitoring of a test, i.e., mammography. - 資料監測 Provide quantifiable evidence of the test (mammography) performance Definition and standard: ACR BI-RADS® 4th ed. (2003) section III. ACR: American College of Radiology BI-RADS: Breast Imaging Reporting and Data System
Why doing medical audit? A concrete feedback for radiologists in mammography interpretation – 判讀成效之具體回饋 Government regulation – 乳房攝影品管的要求 MQSA (Mammography Quality Standard Act) in U.S.A. (1992) Mammography quality assurance program by DOH (Department of Health) in Taiwan
How to ? 明確區分乳房攝影之檢查屬性: screening or diagnostic 依照ACR BI-RADS® 之診斷分類 (assessment category) 完成報告 原始資料 (raw data) 之收集 衍生性資料 (derived data) 之計算 - 陳勁宇等, 使用Microsoft® Office 開發乳房攝之BI-RADS® 資料監測系統, 中華放射醫學雜誌, 2005; 30: 341-346
原始資料 (raw data)
衍生性資料 (derived data)
What’s the meaning? FP – false positive PPV – positive predictive value Cancer detection rate Percentage of minimal cancers Recall rate
False Positives (FP) FP1 = initially screening category 0,4,5 - TP 數量最大, 包含原始篩檢結果異常之所有個案 FP2 = biopsied benign + non-biopsied cases = screening final category 4,5 – TP 數量較小, 包含所有篩檢之最終結果為 BR4 or 5者 FP3 = biopsied benign cases 數量最小, 只包含所有已知做 biopsy 的個案
Positive Predictive Value (PPV) PPV1 = TP / (TP + FP1) 數值最小, 分母包含原始篩檢結果異常之所有個案 PPV2 = TP / (TP + FP2) 數值較大, 分母包含所有篩檢之最終結果為 4or5者 PPV3 = TP / (TP + FP3) 數值更大, 分母只包含所有已知做 biopsy 的個案 若所有最終結果為 BR4 or 5 者皆完成 biopsy, 則 PPV2 = PPV3
Data Interpretation Is it good for the Taiwanese population ?
台灣之乳癌發生率 (1979-2003)
美國之乳癌發生率 (1994-2003) 白種人 非洲裔 亞洲裔 西班牙裔
Reference: Chen CY, et al. Adjusting mammography-audit recommendations in lower-incidence Taiwanese population. - JACR 5(9): 978-985, Sep. 2008.
The Reasonable Initial Screening Results?
May I remind you… Data in Information out Garbage in Garbage out
Thank you very much for your attention 陳勁宇 醫師 Chin-Yu Chen, M.D., M.S. 奇美醫學中心 影像醫學部 Department of Radiology, Chi-Mei Medical Center