MAMMOGRAPHY 之標準化 彰化基督教醫院影像醫學部 林慧玲放射師

Transcription

1 MAMMOGRAPHY 之標準化 彰化基督教醫院影像醫學部 林慧玲放射師

2 Breast anatomy Breast disease Good image quality 目錄 Standard position Special position Mass & Calcification classification

3 Breast anatomy External appearance External landmarks -----Nipple -----Inframammary fold -----Axilla

4 Breast anatomy Internal appearance The parenchyma consists of the following : -----Glandular components -----Lymphatic network -----Blood vessels -----Connective and supportive stroma

5 Breast anatomy Connective and supportive stroma ~ Cooper s ligaments

6 Breast disease Benign 發炎性 ~ 非產後性乳腺炎 產後性乳腺炎 膿腫 腫瘤性 ( 常見者 ) ~ 纖維腺瘤 囊腫 管內乳頭狀瘤 脂肪瘤 腫瘤性 ( 罕見者 ) ~ 腺瘤 血管瘤 葉狀囊肉瘤 ( 可能病變為惡性 ) 平滑肌瘤 纖維瘤等

7 Breast disease Malignant ( 常見者 ) ~ 侵襲性 /or 原位的乳管癌 ( 約 80%) 侵襲性/or 原位的肺 葉癌 ( 約 18%) ( 罕見者 ) ~ 髓狀癌 ( 約 1%) 發炎性癌症 ( 約 1%) 肉瘤 霍奇金氏症 非霍奇金氏淋巴結症 白血病 轉移等

8 Anatomy-Based Imaging issues Is the image quality acceptable Position Exposure Compression

9 Is the image quality acceptable? Position Assess depth of tissue seen:pnl depth on CC should be within 1cm of depth on MLO Fat should be seen posterior to parenchyma in both views: XCCL view may be needed Inferior extent of pectoral muscle at least to level of nipple on MLO view Margin of pectoral muscle convex toward nipple

10 Position IMF elevated: No overlap between bottom of breast and upper abdomen Pectoral muscle seen in about 30 % of CC views For CC view, nipple in midline Nipple in profile both view(less important than including all tissue): Anterior compression MLO view if necessary

11 Standard MLO View & CC View Posterior nipple line A B A-B 1CM

12 Exposure All glandular tissue penetrated adequately Photocell set at densest portion of tissue Lower Kvp better contrast ; keep exposure <200 mas to minimize blur AGD<3mGy

13 Compression Adequate compression prevents motion:goal is at least taut and not painful Less painful in first half of menstrual cycle Less pain if compression gradually applied, patient assists Use small cassettes whenever possible Spreads out tissue Reduces amount of radiation needed

14 Compression Look at calcifications, margins should be sharp Inferior breast at inframammary fold is best place to check for motion,esp.on MLO view Viewing with magnification(either lens or electronic) improves conspicuity of motion blur

15 Imaging Approaches Screening mammography CC and MLO views of each breast Additional views performed as necessary to include all glandular tissue XCCL if glandular tissue in lateral breast extends to edge of CC view Tip shot if anterior tissue not well compressed due to thickness at chest wall Overlapping CC,MLO views if breast too large to image on standard size film/detector

16 Imaging Approaches Diagnostic mammography Examination is tailored to clinical question, performed under direct supervision of radiologist Any number of views are used to answer the question Is there a real abnormality? If finding is real,what is the morphology and level of suspicion for cancer?

17 Image Protocols MLO Cassette/digital receptor placed laterally, parallel to axis of pectoral muscle Technologist manually pulls breast from lateral to medial then applies compression IMF elevated and pulled forward as compression applied

18 The Oblique View (MLO) 55 MLO

19 CC Technologist should elevate cassette/digital receptor to maximum excursion of IMF Minimizes distance compression paddle travels Maximizes depth of tissue included in image As compression applied lateral tissue tugged into field of view Nipple central on CC view XCC Patient rotates medially (XCCM) or laterally (XCCL) to include more tissue at posterior margins in CC projection

20 The Cranial-Caudal View (CC) O CC

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22 XCCM

23 XCCL

24 RCC RXCCL

25 Tip shot : Anterior compression MLO view Breast is thicker at chest wall than at nipple Thickness of posterior tissue limits compression Angled/tilting compression plates help compensate Can also be performed in 90 lateral projection: spreads tissue, additional information

26 Standard MLO TIP SHOT

27 Axillary tail view Variant on MLO projection with emphasis on lateral axillary tissue Edge of cassette/digital detector along lateral chest wall Cental and madial tissue not included

28 ML 90 true lateral, orthogonal to CC, with cassette/ digital detector at lateral breast Does not include as much axillary tail but allows triangulation of lesions seen only on MLO Important for milk of calcium calcifications (Ca ++):shows tea cup,layering configuration LM 90 true lateral, with cassette/ digital detector at medial breast Goal is to better evaluate medial lesions Medial lesions closer to detector less risk of blur

29 The Lateral View - LM 90 LM

30 The Lateral View - ML 90 ML

31 RMLO RLM

32 Rolled CC Upper half of breast tissue rolled laterally(ccrl) Lesions in superior hemisphere move laterally, Inferior lesions move medially Central lesions does not move Upper half of breast tissue rolled medially(ccrm) Lesion in superior hemispheres moves medially Lesion in inferior breast moves laterally

33 Determining the depth of a lesion only seen in one view Determining weather the dense area is real or superimposed structures Roll View

34 Spot compression: Use of small compression paddle to increase local compression over a finding Compression thickness improved resolution Summation shadows can be proven normal Alters the way parenchymal elements overlap May use small cassette/detector in very large breasts

35 Spot Compression view

36 RCC SPOT COMPRESSION

37 Magnification: Geometric magnification of small objects within breast 0.1mm focal spot, breast farther from detector Performed with patient standing Image projects on large area: Reduced noise, scatter better resolution Magnification of Ca + + assess morphology, extent Magnification of mass assess margins, associated Ca+ + if any

38 Magnification

39 LCC LMCC

40 Cleavage view Both breasts placed on cassette/digital detector Evaluates far posteromedial tissue Lumpogram Performed for palpable mass, BB marker on mass Skin over lesion in tangent, spot compression Projects mass over subcutaneous fat rather than over dense tissue Better ability to assess margins,overlying skin US has replaced this technique in many centers

41 Cleavage View

42 Tangential View

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44 Clinical Implications Clinical Importance: In one series cancer detection 84% among patients with proper breast positioning; to 66%with poor positioning Interval cancers more likely after images with poor positioning Odds ratio2.6 Motion blurs Ca++ missed diagnosis, esp. ductal carcinoma in situ(dcis) Poor mobilization of breast deep lesions may not be included in image

45 Clinical Implications Lesions seen on one view only one cause of missed cancer Measure distance from nipple to determine if included in other views For very posterior lesions, may not have been included on both views due to variable positioning

46 Keys to Mammography Quality Maximize compression Optimize Exposure Optimize Positioning Goal:<2% repeat rate

47 Maximize compression Maximum Patient can tolerate Reduces scatter,spreads out tissue better Can use lower KVP(improving contrast),less radiation dose to patient Supplemental anterior MLO or 90 lateral view for better compression in large breasts

48 Optimize Exposure Lower KVP better contrast; need to keep MAS<200 to reduce motion blur If motion is limiting,known Ca++,then acceptable to KVP for shorter exposure

49 Optimize Positioning Elevate IMF prior to MLO exposure Bring in axillary tail tissue on CC view Include fat behind glandular tissue in both views.may need XCCL view to complete exam. Include posterior tissue: Posterior nipple line should measure within 1Cm of same distance on CC vs. MLO view Eliminate skin folds Nipple in profile(less critical than including all tissue):anterior tip view if needed

50 兩側影像比較 -- Focal asymmetry

51 兩側影像比較 -- Focal asymmetry

52 找出 lesion 的位置 Mass Lesion Density Focal asymmetry

53 Mass v.s.. Density 兩個不同方向的 view 都看得到 mass 只在一個方向的 view 看到 density Benign: Equal density or low density (fat containing) Circumscribed margin ( 邊緣整齊 ) Malignancy: High density Ill-defined margin Architectural distortion ( 組織牽扯 )

54 Size Shape Density Mass Number and bi-laterality Contours 輪廓 Well defined Partial lost of contour Partially out of focus and irregular Out of focus Irregular Spiculated

55 RCC RXCCL Fibroadenoma

56 RCC RXCCL

57 BI-RADS Category 6 Invasive Papillary Carcinoma

58 Size Micro calcifications( 鈣化 ) Number/Density Type Shape of the cluster Morphology 形態 Well defined Monomorph., round powdery Irregular linear

59 LCC LMLO

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