BREAST IMAGING MRI ppt DR ABHIJIT R SINGH

BREAST IMAGINGA MRI

1. BREAST IMAGING: MRI DR ABHIJIT R SINGH Resident Radiology SMBT MED COLLEGE .

2. Anatomy and composition Introduction : Focus and foci Masses Morphology T1-T2 characteristics Enhancement pattern of a mass CAD Non-mass enhancement Distribution Internal Enhancement Pattern - Nonmass Associated findings Specific breast tumours Cysts Fibroadenoma Fat containing lesions DCIS Invasive ductal carcinoma Invasive lobular carcinoma Colloid carcinoma Others

3. MAMMOGRAPHY

4. INTRODUCTION Breast MRI is the most sensitive method for detection of breast cancer (BREAST COMPOSITION C, D.) Depending upon on international health regulations : SCREENING of high risk women for developing breast cancer (e.g. BRCA1 and BRCA2 carriers), -obscured breast tissue (SILICON implant) DIAGNOSTIC in -pretherapeutic breast cancer staging (bloody nipple discharge patient), -Mammography and Sonography negative lesion but suspicious on palpation -monitoring of primary systemic therapies and for solving problematic diagnostic situations where direct biopsy is not possible.

5. MRI Breast : Principle to diagnose tumorous lesion Neoangiogenesis by the malignant tumour serves as a basis for BREAST MR imaging. The new blood vessel has increased permeability(leakiness) resulting in early tumour uptake of contrast by tumour on MR imaging. In many but not all cancers this leaky vasculature also results in early washout of contrast ,producing a dynamic enhancement pattern that helps to differentitae benign from malignant lesion

6. BREAST COMPOSITION (OLD 2003 –Based upon % of FG in CAT I - IV) (2013 –ACR GUIDELINE) MAMMO BREAST COMPOSITION (American College of Radiology) COMPOSITION A: Breast are almost fatty ( V sensitive for Mammography -OLD) MRI supportive COMPOSITON B :Scattered areas of fibroglandular density, MRI supportive. COMPOSITON C : Breast are heterogeneously dense which may obscure small masses(less sensitive to mammo as small lesion are hidden) MRI good. COMPOSITION D : Breast are extremely dense ( insensitive for Mammography YOUNG) MRI best.

7. MRI parenchymal enhancement,

8. reconstruction

9. MRI SEQUENCIES USED Dynamic T1-W gradient echo before and after IV gadolinium contrast injection. T2W-FATSAT +/- CONTRAST Diffusion-Weighted Imaging (DWI). Further techniques e.g. proton MR-spectroscopy- seldom applied outside research settings USE OF MRI : 1)IN DEPTH MICROCALCIFICATIONS, 2)SMALL SUSPICIOUS LESION THAT ARE OVERLAPPED IN DENSE BREAST

10. MRI BREAST SPECIFIC TUMOROUS LESION NON MASS ENHANCEMENT FOCUS and FOCI MASSES

11. 1) FOCUS AND FOCI One of the things we run into are 'little bright objects’. As shown by arrow These foci are enhancing areas of less than 5mm in diameter and are too small to characterize. These lesions are typically stable on follow-up and are considered to be a part of the normal background enhancement pattern in the breast.

12. 2 )MASSES MORPHOLOGY Shape : A mass shape can be round, oval, lobulated, or irregular. Lobulated masses have undulating contours. Irregular masses have an uneven shape that cannot be characterized as round, oval, or lobulated. If a mass is irregularly shaped, it has a 32% chance of being malignant. The T2 FATSAT image on the left shows a large, irregular hyperintense mass, which proved to be an ANGIOSARCOMA. The T2 image on the RIGHT is a JUVENILE FIBROADENOMA - it is oval in shape and has homogenous enhancement and smooth margins, i.e. typically benign. The T2 -FATSAT image on the LEFT is another example of a FIBROADENOMA : a lobulated mass with non-enhancing septations

13. Masses MORPHOLOGY Margin Margins can be described as smooth, irregular, or spiculated . Spiculated margins are frequently a feature of malignant breast lesions and radial scars. If a mass has spiculated margins, it has an 80% chance of being malignant. SUBSTRACTION Image below shows a large, round homogenous hyperintense mass with smooth margins, most likely EPIDERMAL INCLUSION CYST

14. MASSES MORPHOLOGY Margin Invasive ductal carcinoma with spiculated margins The image on the far left shows a spiculated mass, i.e. 80% chance of being malignant. . Next to it the corresponding gross pathologic specimen. You can see the spiculations invading the surrounding tissue in both. Just like on mammography, this lesion is has a high likelihood of malignancy and would be labelled BIRADS 5 (INVASIVE DUCTAL CARCINOMA)

15. MORPHOLOGY Margins The DWI image on the RIGHT shows an irregularly shaped mass with irregular margins, which was an INVASIVE DUCTAL CARCINOMA. The SUBSTRACTION image on the LEFT shows a similarly irregularly shaped and irregularly marginated lesion, this time an ADENOID CYSTIC CARCINOMA. RIGHT IRREGULAR MARGIN LEFT IREEGULAR MARGIN and SHAPE

16. T1-T2 Characteristics

17. T1WI

18. High signal INTENSITY on T1 The pre-contrast T1, non fat-suppressed sequence can show the presence of fat in a lesion. Central high signal on a T1-weighted image can be seen in intramammary lymph nodes or fat necrosis. Fat is also seen in hamartomas The T1 W image below shows an example of a fat-containing hamartoma in the breast. Breast lesions containing fat are benign unless they are rapidly growing.

19. High signal on T2-FATSAT In T2 fat-suppressed images we are looking for water. Rule: “Lesions that are bright on T2-FATSAT include cysts, lymph nodes and fat necrosis. These are all benign lesions. ” Exception : there is one malignant lesion that has a high signal intensity on T2 fat-suppressed weighted images. This is the colloid carcinoma . On the image on the left there are multiple rounded areas in both breasts. These are multiple simple cysts.

20. Fibroadenoma (RIGHT) and a Colloid carcinoma (LEFT). Both are bright on T2WI. The T2W image on the RIGHT shows a round lesion with bright signal on T2. This is a FIBROADENOMA. On the LEFT T2W FATSAT is an example of a COLLOID CARCINOMA in a breast with dense, glandular tissue. It is the exception to the rule that all things with bright signal on T2 fat-suppressed images are benign.

21. Moderate and low signal on T2-fatsat. The T2 fat-suppressed sequences are for detecting lesions with high signal, not moderate or low signal. Moderate and low signal intensities can be caused by cancer.

22. Enhancement pattern of a mass Mass enhancement occurs in six main patterns: 1)Homogeneous enhancement is uniform and confluent enhancement throughout the mass. 2)Heterogeneous enhancement is nonuniform enhancement, which varies within the mass. 3)Rim enhancement is enhancement mainly concentrated at the periphery of the mass. This type of enhancement is frequently a feature of high-grade invasive ductal cancer, fat necrosis, and inflammatory cysts. A lesion with rim enhancement that is not a typical cyst has a 40% chance of malignancy. 4)Dark internal septations refers to non-enhancing septations in an enhancing mass. These are typical for fibroadenomas , especially when the lesion has smooth or lobulated margins. 5)Enhancing internal septations are usually a feature of malignancy. 6)Central enhancement is pronounced enhancement of a nidus within an enhancing mass. Central enhancement has been associated with high-grade ductal cancer

23. ENHANCEMENT 1)Homogeneous enhancement The image on the left shows a homogeneously enhancing lesion. This proved to be an INVASIVE DUCTAL CARCINOMA. 2) Heterogenous enhancement On the left, the image shows an irregularly shaped mass with spiculations and a heterogeneous internal enhancement pattern, which proved to be an INVASIVE LOBULAR CARCINOMA

24. 3)Rim enhancement : The image on the left shows rim enhancement of a lesion invading the surrounding tissue in a case of INVASIVE DUCTAL CARCINOMA.

25. NON ENHANCEMENT MASS Distribution Non-mass enhancement is enhancement without three-dimensional characteristics. It is important because it occurs in a significant number of cancers. You need to look at its distribution, its enhancement pattern and its symmetry or asymmetry. The table summarizes the terms used to describe the distribution of non-mass enhancement in the breast. Focal refers to non-mass enhancement in less than 25% of a quadrant of the breast. Ductal involvement is enhancement in a ductal distribution, and is cancer in 60% of cases. Linear enhancement is similar to ductal enhancement, but does not have a ductal orientation. This finding means cancer in 31% of cases. Segmental enhancement refers to multiple ducts and has a 78% chance of being cancer. Regional enhancement is not ductal or segmental but larger than focal and is cancer in 21%. Diffuse non-mass enhancement is typically benign

26. Internal Enhancement Pattern - Nonmass Non-mass enhancement can be termed homogeneous and heterogeneous, just as mass enhancement can. As mentioned earlier, punctate enhancement is usually benign, but it can occur focally. In that case there is a 25% chance of cancer. Clumped enhancement is the most important non-mass enhancing pattern to recognize. It has a 60% chance of cancer (typically DCIS). On the far left heterogeneous enhancement in an invasive ductal carcinoma. The image next to it shows punctate enhancement in a hamartoma with fibrocystic change (arrows)

27. The image on the left shows a mass as well as areas of linear non-mass enhancement. This proved to be linear DCIS with an INVASIVE DUCTAL CARCINOMA Examples of SEGMENTAL AND REGIONAL NON-MASS ENHANCEMENT IN DCIS. The image on the left shows a mass with associated ductal enhancement coming from the mass , which corresponds to anterior and posterior expansion of the tumor in this case of DCIS. The image next to it shows an example of linear non-mass enhancement in a different orientation to that of the ducts in stromal fibrosis.

28. The image on the left shows focal non-mass enhancement. This proved to be a focal DUCTAL Carcinoma In Situ The image on the left shows linear non-mass enhancement. This proved to be STROMAL FIBROSIS.

29. Clumped enhancement Clumped enhancement is the most important non-mass enhancing pattern to recognize. It has a 60% chance of cancer (typically DCIS). On the left two examples of clumped enhancement in DCIS.

30. Temporal Resolution - Kinetic Analysis (Curves) First we look at the initial upslope of the curve during the first one to two minutes. This is either slow, medium or rapid. Then there is the delayed portion - two minutes or more after the injection of contrast. This part of the curve shows either an increase, plateau or washout. The kinetic analysis takes about six minutes of repetitive scanning in total and can lead to three types of curve. Type 1 On the image on the left is a type 1 curve. There is a slow rise and a continued rise with time. A lesion with a type 1 curve has a chance of 6% of being malignant Type 1 curve with slow rise and a continued rise with time

31. Type 3 The type 3 curve shows a rapid initial rise, followed by a drop-off with time (washout) in the delayed phase. A lesion with this type of curve is malignant in 29-77%. This is the red on the CAD (Computer Aided Detection)

32. Type 2 Then there is the type 2 curve, which is in the middle: a slow or rapid initial rise followed by a plateau in the delayed phase, which is allowed a variance of 10% up or down. The chance of a lesion with a type 2 curve being malignant lies somewhere between the 6% of the type 1 curve and the 29-77% of the type 3 curve. Many physicians will biopsy lesions with type 2 curves. For non-mass enhancement, kinetics are not very useful. If there is clumped enhancement in a breast it must be biopsied, even though there are no areas with a type 3 curve.

33. COMPUTER ASSISTED DIAGNOSIS Computer Aided Detection is a purely kinetic evaluation. It does not evaluate the anatomy or pathology of the images. CAD looks at the curves and peak enhancements for the contrast (automated kinetics). It also has some very nice features, including motion registration during subtraction, which can correct for a patient's movement during the exam - something not all MRI scanners can do. It can do multiplanar reconstruction and subtraction very well and very quickly – it also has a good measurement package. The CAD shows a large area of red superimposed on the breast lesion in the image on the left. In CAD, red is bad: it means type 3 washout, and probably cancer

34. The images on the left show a large, abnormally enhancing area in the left breast. The CAD has detected some very small areas with type 3 washout (in red). When you look at CAD images, take note of the worst (red) areas. This was a large invasive ductal carcinoma

35. SPECIFIC BREAST TUMOURS Cysts Fibroadenoma Fat containing lesions DCIS Invasive ductal carcinoma Invasive lobular carcinoma Colloid carcinoma Others

36. CYSTS Cyst have a low signal in T2 W Cysts have a high signal on T2 fat-suppressed images. After the injection of gadolinium, they will show up as filling defects, sometimes with rim enhancement.

37. FIBROADENOMA Fibroadenomas are the most common benign breast lesions after cysts. In order to be certain a lesion is a fibroadenoma, certain criteria must be met: Benign morphologic characteristics Non-enhancing septations A fibroadenoma must have benign spatial characteristics. This means it can not have a spiculated or microlobulated border . On the left an example of a classic fibroadenoma : a round, smoothly marginated lesion with some black or gray areas on the inside, which are the non-enhancing septations. below is another example of a fibroadenoma with clear non-enhancing septations. These septations are also visible on the gross pathology.

38. FAT CONTAINING LESIONS The pre-contrast T1, non fat-suppressed sequence can show the presence of fat in a lesion. High signal on a T1-weighted image can be seen in intramammary lymph nodes, fat necrosis and hamartomas. These areas will be dark on fat suppressed images. On above 2 classic examples of hamartomas. These lesions have fat-containing areas which are suppressed on these images after the administration of intravenous gadolinium.

39. DCIS DUCTAL CARCINOMA IN SITU . Many cases of DCIS show no washout and usually there is slow initial enhancement. The distribution of the enhancement however is important. DCIS typically shows clumped, ductal, linear or segmental non-mass enhancement. On the left a patient with areas of non-mass enhancement in both breasts (DCIS). There is a small enhancing mass medially in the left breast, which was a small invasive carcinoma.

40. The cases on the left are more difficult to diagnose . Both of these patients had large homogeneously enhancing areas in the right breast. In both patients this proved to be DCIS Another case of DCIS, located laterally in both breasts.

41. INVASIVE DUCTAL CARCINOMA Most invasive carcinoma are ductal, some are lobular, and there is a group of rarer types. Regardless of the type of cancer, they typically appear on breast MRI as an irregularly shaped, spiculated mass with rim- or heterogeneous enhancement after the administration of intravenous gadolinium. On the left two cases. The image on the far left is an invasive ductal carcinoma presenting as a large, heterogeneously enhancing mass. Next to it an example of an invasive ductal carcinoma presenting as a smaller mass with rim-enhancement.

42. INVASIVE LOBULAR CARCINOMA Invasive lobular carcinoma is one of the types of cancer that does not always show a lot of enhancement on breast MRI, which can make it difficult to diagnose. In these two cases however, this was not a problem.

43. COLLOID CARCINOMA The image on the left is a T2WI with fat suppression. It is a colloid carcinoma in a breast with dense, glandular tissue. It is the exception to the rule that all things with bright signal on T2 fat-suppressed images are benign.

44. Terminal duct carcinoma

45. SUMMARY OF MRI BREAST SPECIFIC TUMOROUS LESION NON MASS ENHANCEMENT FOCUS and FOCI MASSES

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