**5. MRI acts as a screening tool in a population of asymptomatic women**

Mammography has well-recognized limitations for early breast cancer detection, especially for Asian women with DBPP. In the United States, MRI is provided as an adjunctive screening tool, mainly for women who may be at increased risk for the development of breast cancer. The Society of Breast Imaging and the Breast Imaging Commission of the ACR issue these recommendations to provide guidance to patients and clinicians on the use of imaging to screen for breast cancer. The recommendations are based on available evidence, or based on consensus opinions of professionals and experts from the executive committee of the Society of Breast Imaging and the members of the Breast Imaging Commission of the ACR. These recommendations are intended to suggest appropriate utilization of breast MRI for screening high-risk groups. They are not intended to replace sound clinical judgment and are not to be construed as representing the standard of care. Mammography should be remembered to be the only imaging modality that has been proven to decrease mortality from breast cancer. Before using breast MRI, the potential benefits, limitations, and harm from this additional screening modality should be reviewed (Lee et al., 2010; Saslow et al., 2007).

Similar to Western countries, a higher proportion of Asian women with breast cancer have at least one relative with breast cancer. This risk can be almost double that of the general population. However, the gene correlated with this is different from that found in Western countries. In addition, gene screening programs and services are poorly developed, even in the wealthiest Asian countries. To define the high-risk group in the population, the national screening mammography program in Taiwan provides services for women aged between 40-45 years with a family history of breast cancer. Considering the low sensitivity of mammography in young women, a more aggressive breast MRI screening at this age or lower is recommended. Adjuvant breast MRI screening should also be considered for women with lymphoma (Hodgkin's disease), women who received radiation treatment between the ages of 10 to 30 years, women with lobular carcinoma *in situ* (LCIS), atypical lobular hyperplasia (ALH), and atypical ductal hyperplasia (ADH), which may range from normal ductal hyperplasia to ductal carcinoma *in situ* (DCIS). Specifically, women with a personal history of breast cancer, including DCIS, should be included. As previously mentioned, DBPP has been shown to be an independent risk factor for breast cancer. Women with the highest breast density were found to have a 4- to 6-fold increased risk compared with women with the least dense breasts. In addition, malignant tumors of the breast are more likely to arise in the areas of greatest mammographic density than in fattier areas of the breast. Although the ACS recommendations for Breast MRI Screening as an adjunct to mammography are more detailed, the most suitable indications for Asian women are provided in the following table (**Table 2**; Lee et al., 2010; Saslow et al., 2007)

#### **6. The value of breast MRI as an adjunct in the diagnosis of breast diseases**

Breast MRI can be used as an adjunct in the diagnosis of breast diseases when inconclusive findings in conventional imaging exist, such as with mammography and sonography (BI-RADS 0). Therefore, MRI can be used as a problem-solving modality (Mann et al., 2008). Generally, breast MRI provides a relatively higher negative predictive value for excluding malignancy (Dorrius et al., 2009; Dorrius et al., 2010).

The Application of Breast MRI on Asian Women (Dense Breast Pattern) 31

at risk for familial breast cancer have shown an increased detection rate using this modality than with mammographic screening (Lee et al., 2010). Table 3 summarizes these values.

**Occluded images:** Certain conditions that may impair conventional breast imaging, such as silicone augmentation or radiographically dense breasts, may warrant breast MRI

**Contralateral breast with breast malignancy:** MRI can detect unsuspected disease in the contralateral breast (coincidence positive rate at 4-5% of breast cancer patients), which often provides false negative findings on mammography or sonography **(Figure 2)**. **To differentiate scars from real malignant mass:** Breast MRI can help distinguish

**Suspect of breast cancer recurrence:** Breast MRI may be indicated in women with a past

**Metastatic adenopathy:** MRI provides a full field of view in a single position and an image acquisition that covers major positions of the bilateral axillary lymph nodes and internal mammary chains, which may be missed by mammographic or physical findings

**Determining true tumor extension:** Breast MRI can locate the primary area of breast cancer and define the extent of the disease for definitive therapy. A negative breast MRI may exclude the breast as a potential primary site of cancer and avoid a mastectomy or

**For metastasis:** Breast MRI helps evaluate the breasts in case of metastases of an

patients with silicone implants and silicon injections, in which sonography and mammography are usually inconclusive in defining tumor mass, silicoma, granuloma,

**7. Ability of MRI to describe multifocality and the extent of the disease** 

malignancy in approximately 3 % to 9 % of cases (Lee et al., 2010) (Figure 4).

and intracapsular or extracapsular implant ruptures **(Figure 13,19)**.

**For chemotherapy:** Breast MRI helps evaluate therapy response in patients treated with

**Silicone and nonsilicone breast augmentation:** Breast MRI is useful in the evaluation of

Table 3. The value of breast MRI as an adjunct in the diagnosis of breast diseases (Mann et

For women with newly diagnosed breast cancer, a single round of screening of the contralateral breast with MRI at the time of diagnosis might detect otherwise occult

MRI has been found to be more accurate in assessing tumor extent and multifocality in patients with dense breasts. MRI can improve the detection of cancer in the contralateral breast when added to a thorough clinical breast examination and mammographic evaluation at the time of the initial diagnosis of breast cancer. The increased rate of cancer

**Backup for inconclusive findings and for more detail to evaluate the lesion characterization:** Breast MRI may be indicated when other imaging examinations (sonography and mammography) and physical examinations are inconclusive for the

postoperative scarring or radiation scarring from recurrent cancer.

help minimize the invasive procedure **(Figure 9,10,11)**.

presence of breast cancer **(Figure 14)**.

history of breast cancer.

unknown primary carcinoma.

neoadjuvant chemotherapy **(Figure 7-8)**.

**(Figure 4,5,12)**.

al., 2008).

depending on clinical findings **(Figures 13,19)**.

**Breast MRI Screening as an adjunct to mammography is advised for women** with a family history that may suggest a genetic predisposition to breast cancer (Lee et al., 2010; Saslow et al., 2007)

**Breast MRI Screening recommendations for** who received radiation therapy to the chest in their 2nd or 3rd decade (Saslow et al., 2007)

**Breast MRI Screening recommendations for** patients with lobular carcinoma *in situ*  (LCIS) , atypical lobular hyperplasia (ALH), or atypical ductal hyperplasia (ADH) (Saslow et al., 2007)

**Breast MRI Screening recommendations for** heterogeneously or extremely dense breast tissue, disabling the mammograph from interpretation (Lee et al., 2010; Saslow et al., 2007)

**Breast MRI Screening recommendations for** personal history of breast cancer, including ductal carcinoma *in situ* (DCIS) (Lee et al., 2010; Saslow et al., 2007)

Table 2. MRI acts as a screening tool in a population of asymptomatic women with preselection is listed.

MRI is the most reliable imaging technique for measuring the tumor size, and it detects additional foci of the tumor in the ipsilateral breast in 10–30 % of patients (Mann et al., 2008). The sensitivity of breast MRI is, in the setting of preoperational evaluation, close to 100 %. MRI may be considered after breast-conserving therapy (BCT) as an evaluation tool for residual disease after positive tumor margins. Thus, breast MRI acts as a diagnostic tool for all patients who undergo BCT. Breast MRI is superior for evaluating suspected recurrence compared to clinical examination, mammography, or sonography (Kuhl et al., 2010). Postradiation changes usually occur up to 3 months after radiation therapy and do not reduce the accuracy of MRI for identifying residual or recurrent tumors. The presence of an implant does not seem to decrease the sensitivity of breast MRI. MRI is the most accurate modality in the evaluation of implant integrity. Its sensitivity for rupture is between 80 % and 90 %, and its specificity is approximately 90 %, whereas the sensitivity of mammography is approximately 25 %. MRI may aid explanation surgery as it documents the presence and extent of silicone leakage better than any other imaging modality. In patients with prosthesis and prior breast cancer, MRI may be used to evaluate suspected recurrent disease or as a postoperative screening modality (Mann et al., 2008). Although most MRI-detected lesions can be found (and biopsied) with a second sonography, many cannot. The specificity of MRI in a previous study was 88 %; a biopsy was recommended on the basis of a positive MRI in 13.9 % of the women, and 24.8 % of the biopsies resulted in a diagnosis of breast cancer (Lehman et al., 2007a). MRI resulted in 8.2 % of women undergoing biopsy compared with 2.3 % for mammography and 2.3 % for sonography (Lehman et al., 2007b). The Positve Predictive Values (PPVs) of biopsies obtained by using MRI (43 %) and mammography (50 %) were higher than those of the United States (25 %). Of the cancers identified by MRI alone, approximately 75 % were targeted under sonographic guidance. However, approximately 25 % were removed for biopsy under MRI guidance because only MRI demonstrated the accurate location (Lehman et al., 2007b). In addition, breast MRI identified high-grade DCIS and high-risk lesions that were missed by mammography (Hartman et al., 2004). The call-back and biopsy rates of MRI are higher than for mammography in high-risk populations, while the increased sensitivity of MRI leads to a higher call-back rate and a higher number of cancers detected (Saslow et al., 2007). Women

**Breast MRI Screening recommendations for** who received radiation therapy to the chest

**Breast MRI Screening recommendations for** heterogeneously or extremely dense breast tissue, disabling the mammograph from interpretation (Lee et al., 2010; Saslow et al.,

**Breast MRI Screening recommendations for** personal history of breast cancer, including

MRI is the most reliable imaging technique for measuring the tumor size, and it detects additional foci of the tumor in the ipsilateral breast in 10–30 % of patients (Mann et al., 2008). The sensitivity of breast MRI is, in the setting of preoperational evaluation, close to 100 %. MRI may be considered after breast-conserving therapy (BCT) as an evaluation tool for residual disease after positive tumor margins. Thus, breast MRI acts as a diagnostic tool for all patients who undergo BCT. Breast MRI is superior for evaluating suspected recurrence compared to clinical examination, mammography, or sonography (Kuhl et al., 2010). Postradiation changes usually occur up to 3 months after radiation therapy and do not reduce the accuracy of MRI for identifying residual or recurrent tumors. The presence of an implant does not seem to decrease the sensitivity of breast MRI. MRI is the most accurate modality in the evaluation of implant integrity. Its sensitivity for rupture is between 80 % and 90 %, and its specificity is approximately 90 %, whereas the sensitivity of mammography is approximately 25 %. MRI may aid explanation surgery as it documents the presence and extent of silicone leakage better than any other imaging modality. In patients with prosthesis and prior breast cancer, MRI may be used to evaluate suspected recurrent disease or as a postoperative screening modality (Mann et al., 2008). Although most MRI-detected lesions can be found (and biopsied) with a second sonography, many cannot. The specificity of MRI in a previous study was 88 %; a biopsy was recommended on the basis of a positive MRI in 13.9 % of the women, and 24.8 % of the biopsies resulted in a diagnosis of breast cancer (Lehman et al., 2007a). MRI resulted in 8.2 % of women undergoing biopsy compared with 2.3 % for mammography and 2.3 % for sonography (Lehman et al., 2007b). The Positve Predictive Values (PPVs) of biopsies obtained by using MRI (43 %) and mammography (50 %) were higher than those of the United States (25 %). Of the cancers identified by MRI alone, approximately 75 % were targeted under sonographic guidance. However, approximately 25 % were removed for biopsy under MRI guidance because only MRI demonstrated the accurate location (Lehman et al., 2007b). In addition, breast MRI identified high-grade DCIS and high-risk lesions that were missed by mammography (Hartman et al., 2004). The call-back and biopsy rates of MRI are higher than for mammography in high-risk populations, while the increased sensitivity of MRI leads to a higher call-back rate and a higher number of cancers detected (Saslow et al., 2007). Women

Table 2. MRI acts as a screening tool in a population of asymptomatic women with

ductal carcinoma *in situ* (DCIS) (Lee et al., 2010; Saslow et al., 2007)

**Breast MRI Screening as an adjunct to mammography is advised for women** with a family history that may suggest a genetic predisposition to breast cancer (Lee et al., 2010;

**Breast MRI Screening recommendations for** patients with lobular carcinoma *in situ*  (LCIS) , atypical lobular hyperplasia (ALH), or atypical ductal hyperplasia (ADH)

Saslow et al., 2007)

(Saslow et al., 2007)

preselection is listed.

2007)

in their 2nd or 3rd decade (Saslow et al., 2007)

at risk for familial breast cancer have shown an increased detection rate using this modality than with mammographic screening (Lee et al., 2010). Table 3 summarizes these values.

**Backup for inconclusive findings and for more detail to evaluate the lesion characterization:** Breast MRI may be indicated when other imaging examinations (sonography and mammography) and physical examinations are inconclusive for the presence of breast cancer **(Figure 14)**.

**Occluded images:** Certain conditions that may impair conventional breast imaging, such as silicone augmentation or radiographically dense breasts, may warrant breast MRI depending on clinical findings **(Figures 13,19)**.

**Contralateral breast with breast malignancy:** MRI can detect unsuspected disease in the contralateral breast (coincidence positive rate at 4-5% of breast cancer patients), which often provides false negative findings on mammography or sonography **(Figure 2)**.

**To differentiate scars from real malignant mass:** Breast MRI can help distinguish postoperative scarring or radiation scarring from recurrent cancer.

**Suspect of breast cancer recurrence:** Breast MRI may be indicated in women with a past history of breast cancer.

**Metastatic adenopathy:** MRI provides a full field of view in a single position and an image acquisition that covers major positions of the bilateral axillary lymph nodes and internal mammary chains, which may be missed by mammographic or physical findings **(Figure 4,5,12)**.

**Determining true tumor extension:** Breast MRI can locate the primary area of breast cancer and define the extent of the disease for definitive therapy. A negative breast MRI may exclude the breast as a potential primary site of cancer and avoid a mastectomy or help minimize the invasive procedure **(Figure 9,10,11)**.

**For metastasis:** Breast MRI helps evaluate the breasts in case of metastases of an unknown primary carcinoma.

**For chemotherapy:** Breast MRI helps evaluate therapy response in patients treated with neoadjuvant chemotherapy **(Figure 7-8)**.

**Silicone and nonsilicone breast augmentation:** Breast MRI is useful in the evaluation of patients with silicone implants and silicon injections, in which sonography and mammography are usually inconclusive in defining tumor mass, silicoma, granuloma, and intracapsular or extracapsular implant ruptures **(Figure 13,19)**.

Table 3. The value of breast MRI as an adjunct in the diagnosis of breast diseases (Mann et al., 2008).
