**6. System for description of mammary glands images**

#### **6.1 Terminology**


#### **6.2 Normal signs in the electrical impedance mammogram**

#### **6.2.1 The septa**

The septa (layers) consisting of delicate fibrillary tissue are going deep into the mass of the mammary gland from connective tissue capsule that surrounds it. The septa, radiating from the centre, which form the connective tissue stroma of the mammary gland are characterized by a hyperimpedance structure (Fig. 7).

Fig. 7. EIM. Seven scan planes. Connective tissue septa, radiating from the areola (indicated with arrows).

#### **6.2.2 The parenchyma**

166 Imaging of the Breast – Technical Aspects and Clinical Implication

Type tissue is represented by parenchyma

Type I<sup>а</sup> Amorphous type of mammary gland

predominance. IC=75-90‰.

structure. IC=25-75‰.

IC=10-25‰.

IC < 10‰.

American College of Radiology (ACR).

Mixed type of mammary gland structure with amorphous component

Mixed type of mammary gland

Mixed type of mammary gland structure with acinar/ductal component predominance. High density of acinar/ductal component.

acinar/ductal component.

Acinar/ductal type of mammary gland structure. Extremely high density of

**6. System for description of mammary glands images** 

gray-scale - changes from black to white, respectively.

**6.2 Normal signs in the electrical impedance mammogram** 

characterized by a hyperimpedance structure (Fig. 7).

Table 3. Mammary gland structure from the perspective of electrical impedance mammography execution and breast density types according to the classification of the

Electrical conductivity scale - electrical conductivity index values from 0 to 1.00, or in

 Hyperimpedance structure, lesion - electrical conductivity is lower than electrical conductivity of the surrounding tissue of the breast and corresponds to IC < 0.20. Isoimpedance structure, lesion - electrical conductivity is approximately equal to the electrical conductivity of the surrounding tissue of the breast and corresponds to IC =

 Hypoimpedance structure, lesion - electrical conductivity is higher than the electrical conductivity of the surrounding tissue of the breast and corresponds to IC = 0.6-0.8. Animpedance structure, lesion - electrical conductivity is considerably higher than the electrical conductivity of the surrounding tissue of the breast and corresponds to IC >

The septa (layers) consisting of delicate fibrillary tissue are going deep into the mass of the mammary gland from connective tissue capsule that surrounds it. The septa, radiating from the centre, which form the connective tissue stroma of the mammary gland are

Ib

Type II

Type III

Type IV

**6.1 Terminology** 

0.3-0.5.

0.90.

**6.2.1 The septa** 

*EIM* classification *ACR* classification

Fat with some fibroglandular tissue. 25-50% of tissue is represented by parenchyma

Heterogeneously dense. 50-75% of tissue is represented by parenchyma

Extremely dense. 75-100% of parenchyma tissue.

structure. IC >90‰. Predominantly fat. Under 25% of

One distinguishes the parenchyma, which consists of alveolar-tubular glands, and the connective tissue stroma, which is represented by a small amount of cells, delicate fibres and ground intercellular substance. The parenchyma is characterized by an isoimpedance structure and is located between the septa. (Fig. 8).

Fig. 8. EIM. Seven scan planes. Parenchyma as isoimpedance areas located between the connective tissue septa (indicated with arrows).

#### **6.2.3 The lactiferous sinus zone**

Before reaching the nipple milk ducts gain in breadth and create a lactiferous sinus (sinus lactiferi) which accumulates secreta as well as the milk. There are about 15-25 sini in the retromammilary area. The lactiferous sinus zone is visualized as a vast hypoimpedance area located in the centre of the mammogram (fig. 9).

Fig. 9. EIM. Seven scan planes. A hypoimpedance area in the centre of the mammogram corresponds to the location of the lactiferous sinus zone (indicated with arrows).

#### **6.2.4 The nipple**

The nipple consists of the excretory ducts of the breast lobes, surrounded by fibrous tissue and a large number of sebaceous glands. High electrical impedance of the nipple is determined by the absence of the excretory ducts of perspiratory glands in it. In the electrical impedance tomogram the nipple is visualized in the centre as a circular or linear hyperimpedance area, located closely to the lactiferous sinus zone (fig. 10).

Standards for Electrical Impedance Mammography 169

b. Oval – an ellipsoid or obovoid lesion (Fig. 13). The size is determined by longitudinal and

Fig. 13. EIM. Seven scan planes. The obovoid lesion is visualized at 9 on the clock dial

c. Lobular – a lesion with the undulated contour (Fig. 14). The size is determined by

Fig. 14. EIM. Seven scan planes. In the upper segment at 12 on the clock dial, there can be

d. Irregular - the shape of a lesion cannot be characterized and does not correspond to

Fig. 15. EIM. Seven scan planes. In the upper segment there can be visualized a lesion with a

**6.3.2 Assessment of volumetric lesion contours in accordance with the terms of BI-**

a. Sharp (well defined or distinct) – the contours of a lesion are clearly observable. Abrupt

Fig. 16. EIM. Seven scan planes. The lesion with a sharp distinct contour is visualized at 9 on

lateral axes. Typical example – fibroadenoma, cancer.

longitudinal and lateral axes. Typical example – fibroadenoma.

round, oval or lobular (Fig. 15). Typical example – breast cancer.

observed two round hypoimpedance lesions.

lobed contour (indicated with arrows).

the clock dial (indicated with arrows).

junction of the lesion and surrounding tissues (Fig. 16).

**RADS ACR** 

(indicated with arrows).

Fig. 10. EIM. Seven scan planes. The nipple is visualized in the centre as a rounded hyperimpedance area (indicated with arrows). In the centre of the nipple there are excretory ducts which are characterized by hypoimpedance. Around the nipple there is the hypoimpedance area of the lactiferous sinus zone.

#### **6.2.5 The areola**

In the dermis of areola there are circular smooth muscle fibres, numerous sebaceous glands and a large number of pigment cells. Large sebaceous glands located on the periphery of the areola cause the formation of protrusions (Montgomery's tubercles). High electrical impedance of the areola, as well as that of the nipple, is determined by the absence of the excretory ducts of perspiratory glands in it. In the electrical impedance mammogram the areola is visualized as a circular hyperimpedance formation surrounding the lactiferous sinus zone (fig. 11).

Fig. 11. EIM. Seven scan planes. A hyperimpedance area in the centre of the mammogram corresponds to the location of the areola (indicated with arrows).

#### **6.3 Volumetric lesion**

Volumetric lesion – a dimensional lesion, detected in several scan planes. The analysis of images includes assessment of the shape, contour, internal electrical structure and changes of the surrounding tissues.

#### **6.3.1 Assessment of volumetric lesion shape in accordance with the terms of BI-RADS ACR**

a. Round – a lesion of a spherical, circular or spherical shape (Fig. 12). The size is determined by lesion's diameter. Typical example – a cyst.

Fig. 12. EIM. Seven scan planes. In the upper segment there can be visualized two lesions of rounded shape (indicated with arrows).

Fig. 10. EIM. Seven scan planes. The nipple is visualized in the centre as a rounded

ducts which are characterized by hypoimpedance. Around the nipple there is the

hypoimpedance area of the lactiferous sinus zone.

**6.2.5 The areola** 

sinus zone (fig. 11).

**6.3 Volumetric lesion** 

**RADS ACR** 

of the surrounding tissues.

by lesion's diameter. Typical example – a cyst.

rounded shape (indicated with arrows).

hyperimpedance area (indicated with arrows). In the centre of the nipple there are excretory

In the dermis of areola there are circular smooth muscle fibres, numerous sebaceous glands and a large number of pigment cells. Large sebaceous glands located on the periphery of the areola cause the formation of protrusions (Montgomery's tubercles). High electrical impedance of the areola, as well as that of the nipple, is determined by the absence of the excretory ducts of perspiratory glands in it. In the electrical impedance mammogram the areola is visualized as a circular hyperimpedance formation surrounding the lactiferous

Fig. 11. EIM. Seven scan planes. A hyperimpedance area in the centre of the mammogram

Volumetric lesion – a dimensional lesion, detected in several scan planes. The analysis of images includes assessment of the shape, contour, internal electrical structure and changes

a. Round – a lesion of a spherical, circular or spherical shape (Fig. 12). The size is determined

Fig. 12. EIM. Seven scan planes. In the upper segment there can be visualized two lesions of

**6.3.1 Assessment of volumetric lesion shape in accordance with the terms of BI-**

corresponds to the location of the areola (indicated with arrows).

b. Oval – an ellipsoid or obovoid lesion (Fig. 13). The size is determined by longitudinal and lateral axes. Typical example – fibroadenoma, cancer.

Fig. 13. EIM. Seven scan planes. The obovoid lesion is visualized at 9 on the clock dial (indicated with arrows).

c. Lobular – a lesion with the undulated contour (Fig. 14). The size is determined by longitudinal and lateral axes. Typical example – fibroadenoma.

Fig. 14. EIM. Seven scan planes. In the upper segment at 12 on the clock dial, there can be observed two round hypoimpedance lesions.

d. Irregular - the shape of a lesion cannot be characterized and does not correspond to round, oval or lobular (Fig. 15). Typical example – breast cancer.

Fig. 15. EIM. Seven scan planes. In the upper segment there can be visualized a lesion with a lobed contour (indicated with arrows).

#### **6.3.2 Assessment of volumetric lesion contours in accordance with the terms of BI-RADS ACR**

a. Sharp (well defined or distinct) – the contours of a lesion are clearly observable. Abrupt junction of the lesion and surrounding tissues (Fig. 16).

Fig. 16. EIM. Seven scan planes. The lesion with a sharp distinct contour is visualized at 9 on the clock dial (indicated with arrows).

Standards for Electrical Impedance Mammography 171

Fig. 20. EIM. Seven scan planes. The lesion with isoimpedance structure is visualized at 12

c. Hypoimpedance - electrical conductivity of the lesion is higher than that of the

Fig. 21. EIM. Seven scan planes. In the upper segment there can be visualized three

d. Animpedance - electrical conductivity of the lesion is considerably higher than that of the

Fig. 22. EIM. Seven scan planes. In the upper segment, at 12 on the clock dial there is an irregular-shaped lesion with animpedance structure (highlighted in red and indicated with

a. Skin thickening – a significant one-sided hyperimpedance change of the contour around

Fig. 23. EIM. Seven scan planes. A pronounced hyperimpedance change of the contour

**6.4 Assessment of volumetric lesion influence on the surrounding tissue in** 

the mammary gland (Fig. 23). Typical example – mastitis-like carcinoma.

**accordance with the terms of BI-RADS ACR** 

around the mammary gland (indicated with arrows).

surrounding tissue of the breast (Fig. 21). Typical example – a cyst.

hypoimpedance lesions of rounded shape (indicated with arrows).

surrounding tissue of the breast (Fig. 22). Typical example – breast cancer.

on the clock dial (indicated with arrows).

arrows).

b. Vague, indistinct (poorly observable) – the contours of a lesion are uneasy to define. The transition between the lesion and surrounding tissues is gradual and indistinct (Fig. 17). Typical example of an invasive ductal carcinoma.

Fig. 17. EIM. Seven scan planes. The irregular-shaped lesion with indistinct contours is visualized at 12-3 on the clock dial (indicated with arrows).

c. Infiltrated - the contours of a lesion are clearly distinguishable and are characterized by hyperimpedance (Fig. 18). Typical example – breast cancer.

Fig. 18. EIM. Seven scan planes. The obovoid lesion with hyperimpedance contours is visualized at 3 on the clock dial (indicated with arrows).

#### **6.3.3 Assessment of the internal electrical structure of a volumetric lesion**

Taken separately, the internal electrical structure of the lesion is not the criterion for judging on its possible malignancy. However, it is an important characteristic, especially in combination with other evaluation criteria. The increase of electrical conductivity is correlated with an increase of the probability of malignancy.

a. Hyperimpedance - electrical conductivity of the lesion is lower than electrical conductivity than that of the surrounding tissue of the breast (Fig. 19). Typical example – mastitis in the stage of infiltration.

Fig. 19. EIM. Seven scan planes. The obovoid lesion with hyperimpedance structure is visualized at 8 on the clock dial (indicated with arrows).

b. Isoimpedance - electrical conductivity of the lesion corresponds to that of the surrounding tissue of the breast (Fig. 20). Typical examples – fibroadenoma, cancer.

b. Vague, indistinct (poorly observable) – the contours of a lesion are uneasy to define. The transition between the lesion and surrounding tissues is gradual and indistinct (Fig. 17).

Fig. 17. EIM. Seven scan planes. The irregular-shaped lesion with indistinct contours is

Fig. 18. EIM. Seven scan planes. The obovoid lesion with hyperimpedance contours is

Taken separately, the internal electrical structure of the lesion is not the criterion for judging on its possible malignancy. However, it is an important characteristic, especially in combination with other evaluation criteria. The increase of electrical conductivity is

a. Hyperimpedance - electrical conductivity of the lesion is lower than electrical conductivity than that of the surrounding tissue of the breast (Fig. 19). Typical example –

Fig. 19. EIM. Seven scan planes. The obovoid lesion with hyperimpedance structure is

b. Isoimpedance - electrical conductivity of the lesion corresponds to that of the surrounding

**6.3.3 Assessment of the internal electrical structure of a volumetric lesion** 

c. Infiltrated - the contours of a lesion are clearly distinguishable and are characterized by

Typical example of an invasive ductal carcinoma.

visualized at 12-3 on the clock dial (indicated with arrows).

hyperimpedance (Fig. 18). Typical example – breast cancer.

visualized at 3 on the clock dial (indicated with arrows).

correlated with an increase of the probability of malignancy.

visualized at 8 on the clock dial (indicated with arrows).

tissue of the breast (Fig. 20). Typical examples – fibroadenoma, cancer.

mastitis in the stage of infiltration.

Fig. 20. EIM. Seven scan planes. The lesion with isoimpedance structure is visualized at 12 on the clock dial (indicated with arrows).

c. Hypoimpedance - electrical conductivity of the lesion is higher than that of the surrounding tissue of the breast (Fig. 21). Typical example – a cyst.

Fig. 21. EIM. Seven scan planes. In the upper segment there can be visualized three hypoimpedance lesions of rounded shape (indicated with arrows).

d. Animpedance - electrical conductivity of the lesion is considerably higher than that of the surrounding tissue of the breast (Fig. 22). Typical example – breast cancer.

Fig. 22. EIM. Seven scan planes. In the upper segment, at 12 on the clock dial there is an irregular-shaped lesion with animpedance structure (highlighted in red and indicated with arrows).

#### **6.4 Assessment of volumetric lesion influence on the surrounding tissue in accordance with the terms of BI-RADS ACR**

a. Skin thickening – a significant one-sided hyperimpedance change of the contour around the mammary gland (Fig. 23). Typical example – mastitis-like carcinoma.

Fig. 23. EIM. Seven scan planes. A pronounced hyperimpedance change of the contour around the mammary gland (indicated with arrows).

Standards for Electrical Impedance Mammography 173

Fig. 28. EIM. Seven scan planes. Alteration of the normal mammographic scheme represented by a hyperimpedance lesion at 7 on the clock dial (indicated with arrows).

Fig. 29. EIM. Seven scan planes. Total alteration of the age-related electrical impedance

observed deformation and fragmentation of the lactiferous sinus zone (Fig. 31).

Fig. 30. EIM. Seven scan planes. There is a vast undistorted hypoimpedance area in the centre of the mammogram, which corresponds to the location of the lactiferous sinus zone.

Fig. 31. EIM. Seven scan planes. There is a divided hypoimpedance area in the centre of the

mammogram, which corresponds to the location of the lactiferous sinus zone. It is

The visualization of lactiferous sinus zone depends on the age and physiological period of a patient. In women of elder age during the postmenopause the lactiferous sinus zone is hardly visualized. An extensive round hypo- or animpedance area in the centre of the mammogram is typical for the lactation period (Fig. 30). When pathology, there can be

structure.

highlighted in red.

**6.5 Lactiferous sinus zone assessment** 

b. Skin extrusion or retraction – a local change of mammary gland contour: In case of the retraction – into the mamma, in case of extrusion – entoectad (Fig. 24, 25). Typical example – breast cancer, mastitis.

Fig. 24. EIM. Seven scan planes. In the upper segment, a change of the contour (retraction) of the mammary gland (indicated with arrows)

Fig. 25. EIM. Seven scan planes. At 7 on the clock dial, a change of the contour (extrusion) of the mammary gland (indicated with arrows).

c. Skin or nipple infiltration – a local hyperimpedance change of the contour of a mammary gland or of a nipple (Fig. 26, 27). Typical example – breast cancer, Paget's cancer.

Fig. 26 EIM. Seven scan planes. A unilateral local hyperimpedance change of the mammary gland contour (indicated with arrows).

Fig. 27. EIM. Seven scan planes. A unilateral hyperimpedance change of the nipple contour (indicated with arrows).

d. Alterations of the breast anatomy – focal disruption of the normal mammographic scheme. Alteration of the age-related electrical impedance structure (Fig. 28, 29). Typical example – mastitis, breast cancer.

b. Skin extrusion or retraction – a local change of mammary gland contour: In case of the retraction – into the mamma, in case of extrusion – entoectad (Fig. 24, 25). Typical example –

Fig. 24. EIM. Seven scan planes. In the upper segment, a change of the contour (retraction) of

Fig. 25. EIM. Seven scan planes. At 7 on the clock dial, a change of the contour (extrusion) of

c. Skin or nipple infiltration – a local hyperimpedance change of the contour of a mammary

Fig. 26 EIM. Seven scan planes. A unilateral local hyperimpedance change of the mammary

Fig. 27. EIM. Seven scan planes. A unilateral hyperimpedance change of the nipple contour

d. Alterations of the breast anatomy – focal disruption of the normal mammographic scheme. Alteration of the age-related electrical impedance structure (Fig. 28, 29). Typical

gland or of a nipple (Fig. 26, 27). Typical example – breast cancer, Paget's cancer.

breast cancer, mastitis.

the mammary gland (indicated with arrows)

the mammary gland (indicated with arrows).

gland contour (indicated with arrows).

(indicated with arrows).

example – mastitis, breast cancer.

Fig. 28. EIM. Seven scan planes. Alteration of the normal mammographic scheme represented by a hyperimpedance lesion at 7 on the clock dial (indicated with arrows).

Fig. 29. EIM. Seven scan planes. Total alteration of the age-related electrical impedance structure.

#### **6.5 Lactiferous sinus zone assessment**

The visualization of lactiferous sinus zone depends on the age and physiological period of a patient. In women of elder age during the postmenopause the lactiferous sinus zone is hardly visualized. An extensive round hypo- or animpedance area in the centre of the mammogram is typical for the lactation period (Fig. 30). When pathology, there can be observed deformation and fragmentation of the lactiferous sinus zone (Fig. 31).

Fig. 30. EIM. Seven scan planes. There is a vast undistorted hypoimpedance area in the centre of the mammogram, which corresponds to the location of the lactiferous sinus zone.

Fig. 31. EIM. Seven scan planes. There is a divided hypoimpedance area in the centre of the mammogram, which corresponds to the location of the lactiferous sinus zone. It is highlighted in red.

Standards for Electrical Impedance Mammography 175

Fig. 33. Upper row – EIM. Seven scan planes. Breast cancer. Bottom row - EIM. Seven scan planes. Healthy gland. The second row shows the divergence between the histograms of

In order to sort out the diagnostic criteria the diagnostic chart was created, in which each

Using the numerical score for evaluation of volumetric and non-volumetric lesions within the mammary gland in electrical impedance mammography allowed comparing this

The above description of the system of images and diagnostic criteria for electrical impedance mammography provides diagnostics of various breast diseases, including neoplastic, inflammatory, dishormonal and other disorders. However, we believe the detection of breast cancer at early stages to be the high-priority of the method. The basic features of electrical impedance mammography in early diagnostics of breast cancer are the

If the method of diagnostics under examination permits to acquire a numerical result, the so-called "breaking point" (the value exceeding of which is considered as a sufficient cause for qualitative assessment) should be determined. In this case the estimation of diagnostic

electrical conductivity distribution of the affected and healthy gland.

criterion was measured in points (Table 4).

**8. Early diagnostics of breast cancer** 

following.

information to BI-RADS ACR categories (See Table 5).

**7. Diagnostic criteria for electrical impedance mammography** 

#### **6.6 Age-related and comparative electrical conductivity**

#### **6.6.1 Age-related conductivity**

Age-related conductivity is the alteration of electrical conductivity of the breast with respect to age-related percentile curve of electrical conductivity (Fig. 32). The so-called percentile method as an approach to brief description of distributions is wide-spread in medical and biological research. This method does not require the data on distribution structure, i.e. it is non-parametric. The assessment of the average electrical conductivity in healthy women of different ages allowed creating the percentile curves of age-related electrical conductivity.

Fig. 32. Percentile curves of age-related electrical conductivity.

According to these curves each age group corresponds to a certain range of electrical conductivity. In accordance with the proposed assessment rules, the values which are less than 5th percentile shall be considered as pronouncedly low, from 5 to 25 percentiles - as low, from 25 to 75 percentiles - as medium, from 75 to 95 percentiles - as heightened and above 95 percentile – as pronouncedly heightened (Fig. 32). Formation of groups of people with heightened risk of breast cancer development can be performed using the percentile curves of the age-related electrical conductivity.

#### **6.6.2 Comparative conductivity**

Comparative conductivity is the alteration of electrical conductivity of one breast with respect to the other (Fig. 33). The histograms of the electrical conductivity distribution variance percent is chosen with the help of the Kolmogorov-Smirnov nonparametric test (more than 40%) and is highly informative (j>3.0 according to Kullback). Typical example – breast cancer, mastitis.

Age-related conductivity is the alteration of electrical conductivity of the breast with respect to age-related percentile curve of electrical conductivity (Fig. 32). The so-called percentile method as an approach to brief description of distributions is wide-spread in medical and biological research. This method does not require the data on distribution structure, i.e. it is non-parametric. The assessment of the average electrical conductivity in healthy women of different ages allowed creating the percentile curves of age-related electrical conductivity.

**6.6 Age-related and comparative electrical conductivity** 

Fig. 32. Percentile curves of age-related electrical conductivity.

curves of the age-related electrical conductivity.

**6.6.2 Comparative conductivity** 

breast cancer, mastitis.

According to these curves each age group corresponds to a certain range of electrical conductivity. In accordance with the proposed assessment rules, the values which are less than 5th percentile shall be considered as pronouncedly low, from 5 to 25 percentiles - as low, from 25 to 75 percentiles - as medium, from 75 to 95 percentiles - as heightened and above 95 percentile – as pronouncedly heightened (Fig. 32). Formation of groups of people with heightened risk of breast cancer development can be performed using the percentile

Comparative conductivity is the alteration of electrical conductivity of one breast with respect to the other (Fig. 33). The histograms of the electrical conductivity distribution variance percent is chosen with the help of the Kolmogorov-Smirnov nonparametric test (more than 40%) and is highly informative (j>3.0 according to Kullback). Typical example –

**6.6.1 Age-related conductivity** 


Fig. 33. Upper row – EIM. Seven scan planes. Breast cancer. Bottom row - EIM. Seven scan planes. Healthy gland. The second row shows the divergence between the histograms of electrical conductivity distribution of the affected and healthy gland.

## **7. Diagnostic criteria for electrical impedance mammography**

In order to sort out the diagnostic criteria the diagnostic chart was created, in which each criterion was measured in points (Table 4).

Using the numerical score for evaluation of volumetric and non-volumetric lesions within the mammary gland in electrical impedance mammography allowed comparing this information to BI-RADS ACR categories (See Table 5).

The above description of the system of images and diagnostic criteria for electrical impedance mammography provides diagnostics of various breast diseases, including neoplastic, inflammatory, dishormonal and other disorders. However, we believe the detection of breast cancer at early stages to be the high-priority of the method. The basic features of electrical impedance mammography in early diagnostics of breast cancer are the following.

#### **8. Early diagnostics of breast cancer**

If the method of diagnostics under examination permits to acquire a numerical result, the so-called "breaking point" (the value exceeding of which is considered as a sufficient cause for qualitative assessment) should be determined. In this case the estimation of diagnostic

Standards for Electrical Impedance Mammography 177

Fig. 34. High electrical conductivity area (above 0.95 cu) outside the lactiferous sinus zone,

The example of electrical impedance diagnostic. Figure 35 represents the electrical impedance mammogram of a patient. There can be distinguished a focal lesion, in the form of animpedance area, highlighted with red, with electrical conductivity index over 0.95 conditional units. This is the criterion for early diagnostics of breast cancer. Roentgenogram

Fig. 35. EIM. Amorphous type of mammary gland structure. In the outer segment of the left mammary gland, at 3 o'clock position there is observed an animpedance area, which is

Fig. 36. Roentgenogram (left): fibro-fatty involution. In upper-outer segment there is observed

a lesion up to 1 cm in size with a radiant contour. Ultrasound (right): The structure of parenchyma with adipose lobules and connective tissue layers. An inhomogeneous 8х7 mm lesion of irregular shape is located at 28 mm distance from the nipple and at 12 mm depth.

and US image of the same mammary gland are represented below (Fig. 36).

highlighted with red in the second scan plane, less than 10 mm in size.

which is highlighted with red (indicated with arrows).


Table 4. Diagnostic criteria for differentiating volumetric lesions in electrical impedance mammography.


Table 5. EIM numerical score allows for standardizing the description of volumetric lesions and for the usage of patient monitoring algorithm, developed by the American College of Radiology in electrical impedance mammography.

technique efficiency may be limited to sensitivity and specificity assessment. The diagnostic criterion when screening for early stages of breast cancer is the following: high electrical conductivity areas (above 0.95 cu) outside the lactiferous sinus zone – the so-called animpedance areas, which differ markedly from electrical conductivity of healthy mamma's areas (Fig. 34).

It seems that membrane permeability increase is necessary in both directions to support vital activity of dedifferentiated cells during the intraductal stage of oncologic process. The membrane permeability of cancer cells during intraductal and early extraductal stage increases both for chemical compounds and electric charges. This process results in increase of electrical conductivity.

**Shape** 

**Contour** 

round, oval lobular, irregular

hyperimpedance, indistinct

hyperimpedance (IC <0.2)

animpedance (IC > 0.90)

**Comparative electrical conductivity** 

*Common scale BI-RADS categories* no score BI-RADS 0 poor image

structure alteration/displacement thickening/extrusion/retraction

iso- and hypoimpedance (IC = 0.3-0.8)

divergence between the histograms < 30% divergence between the histograms 30-40 % divergence between the histograms > 40%

EIM ACR

4 BI-RADS 3 probably benign findings 5-7 BI-RADS 4 suspicious abnormality - biopsy

0-1 BI-RADS 1 lesion is not defined

Radiology in electrical impedance mammography.

Table 4. Diagnostic criteria for differentiating volumetric lesions in electrical impedance

8-10 BI-RADS 5 highly suggestive of malignancy – treatment/biopsy

Table 5. EIM numerical score allows for standardizing the description of volumetric lesions and for the usage of patient monitoring algorithm, developed by the American College of

technique efficiency may be limited to sensitivity and specificity assessment. The diagnostic criterion when screening for early stages of breast cancer is the following: high electrical conductivity areas (above 0.95 cu) outside the lactiferous sinus zone – the so-called animpedance areas, which differ markedly from electrical conductivity of healthy mamma's

It seems that membrane permeability increase is necessary in both directions to support vital activity of dedifferentiated cells during the intraductal stage of oncologic process. The membrane permeability of cancer cells during intraductal and early extraductal stage increases both for chemical compounds and electric charges. This process results in increase

2-3 BI-RADS 2 benign tumours – routine mammography

sharp

preserved

**Internal electrical structure** 

**Surrounding tissues** 

mammography.

areas (Fig. 34).

of electrical conductivity.

Diagnostic criteria Electrical impedance mammography

points

1 2

1 2

0 1 2

0 1 2

0 1 2

Fig. 34. High electrical conductivity area (above 0.95 cu) outside the lactiferous sinus zone, which is highlighted with red (indicated with arrows).

The example of electrical impedance diagnostic. Figure 35 represents the electrical impedance mammogram of a patient. There can be distinguished a focal lesion, in the form of animpedance area, highlighted with red, with electrical conductivity index over 0.95 conditional units. This is the criterion for early diagnostics of breast cancer. Roentgenogram and US image of the same mammary gland are represented below (Fig. 36).

Fig. 35. EIM. Amorphous type of mammary gland structure. In the outer segment of the left mammary gland, at 3 o'clock position there is observed an animpedance area, which is highlighted with red in the second scan plane, less than 10 mm in size.

Fig. 36. Roentgenogram (left): fibro-fatty involution. In upper-outer segment there is observed a lesion up to 1 cm in size with a radiant contour. Ultrasound (right): The structure of parenchyma with adipose lobules and connective tissue layers. An inhomogeneous 8х7 mm lesion of irregular shape is located at 28 mm distance from the nipple and at 12 mm depth.

**8** 

*USA* 

**The Role of Molecular Imaging Technologies in** 

Anatomic breast imaging techniques such as mammography and ultrasound are very useful in the detection of breast cancer, but can have limited sensitivity and positive predictive value, particularly in patients with dense breasts (Kolb et al., 2002). These limitations have provided the impetus for adjunctive technologies such as nuclear medicine and PET based diagnostic imaging procedures. The nuclear medicine based technique is referred to as Breast-Specific Gamma Imaging (BSGI) or molecular breast imaging (MBI) while the positron-emission tomography (PET) based technique is referred to as Positron Emission Mammography (PEM). Both have demonstrated good results in clinical studies and are increasingly being adopted into clinical practice. Although these imaging techniques have similarities, they are different in several aspects. This chapter is designed to provide an overview of these imaging technologies and their potential roles in patient management.

Both BSGI/MBI and PEM are physiologic imaging modalities conducted through the injection of a pharmaceutical, called a tracer, which is tagged with a radioactive isotope and the resulting molecule is called a radiotracer. Each radiotracer is designed to bind to a specific target (organ, tissue, physiologic process, cell receptor or protein) while the isotope tag emits radiation that is detected by cameras placed near the patient. The cameras provide an image of the distribution of the radiotracer tracer and thus measure a specific physiologic

There are two types of radioactive isotope tags used in medical imaging: single gamma emission isotopes and positron emission isotopes. Single gamma emission isotopes release a gamma ray from the nucleus. There are a variety of single gamma isotopes used in nuclear medicine. The most common isotopes used in diagnostic imaging are referred to as lowenergy isotopes with gamma-ray energies ranging from 80 – 200 kiloelectron volts (keV). The gamma ray is a photon with sufficient energy to exit the body and be captured by specially designed detectors called gamma cameras. Positron emission isotopes emit a

**1. Introduction** 

**2. Radiotracers** 

**2.1 Isotopes** 

process in the area being imaged.

**Breast Cancer Diagnosis and Management** 

*Jefferson University, Hampton University, University of Virginia, Legacy Good* 

Anne Rosenberg, Douglas Arthur Kieper, Mark B. Williams,

Nathalie Johnson and Leora Lanzkowsky

*Samaritan, Nevada Imaging Center* 

With such a breaking point the sensitivity and specificity of electrical impedance mammography are quite high: sensitivity is 84-93%, specificity – 87-99% (according to the data given by different authors).

Impedance mammography is in the beginning of its development. The authors sincerely hope that their modest paper will help to arouse interest of a wide range of medical researchers.
