Full Breast Ultrasonography and the Ultrasound: BI-RADS Assessment

Abstract

The US Breast Imaging Reporting and Data System (BI-RADS) assessment which is useful for standardized reporting and the management of breast diseases is presented, together with its limits issued from the descent from the mammographically BI-RADS and from the lack of anatomical precision of the classical US. In parallel, the necessity of a completed US BI-RADS, where the vasculature and the strain play a major role in the diagnosis, is recommended for the anatomical technique of FBU.

5.1 Importance of the Ultrasound BI-RADS Assessment

The necessity of standardization of the reporting and of the management of the mammogram findings for screening and diagnosis determined the issue of guidelines. The mammographic Breast Imaging Reporting and Data System (BI-RADS^®) assessment improved the characterization of the opacities as masses, distortion of the architecture or calcifications, and the final recommendations were included in the American standards since 1992 (MQSA, Mammography Quality Standards Act). BI-RADS^® for mammography is published and trademarked by the American College of Radiology (ACR); it has been used widely in the USA, nowadays being accepted worldwide and becoming the principal tool for the classification and the management of the screening programs. Actually, the fourth edition is in use since 2003.

There is some confusion created by the French lexicon named the “Classification ACR,” adopted by the French Haute Autorité de Santé and the National Committee for Breast Cancer Screening, which is adapted from BI-RADS but influenced by the French national screening program, with the aim to limit undesirable risks of screening (false positives and overdiagnosis).

The actually in use BI-RADS Atlas from 2003 (updated in 2013) includes new sections for US (ACR BI-RADS–US) and MRI (ACR BI-RADS–MRI). ACR BI-RADS–US (2003) may help standardize the terms used for characterizing and reporting lesions, thereby facilitating patient care, the characterization of lesions, and the development of possible screening applications [1]. It opened the way for the screening US, without solving the problem of standardization of the technique of US acquisition even after the lexicon of 2013 [2], which was developed independently by Teboul and his collaborators under the name of ductal echography.

The classical US was growing importance in providing specificity to mammographically observed lesions for avoiding unnecessary biopsies; moreover, US had to detect occult carcinomas in dense breasts where mammography was inefficient, and to guiding procedures, easier for the patient and for the operator than by the mammographically guidance. All these tasks for US determined its complementary position in the diagnosis of breast cancer, neglecting the differential diagnosis between benign lesions and completely ignoring the possibility of using US as first-intention technique of imaging diagnosis in symptomatic cases or screening. However, the development of a standardized group of descriptors and an assessment and management scheme for US became necessary, and inevitably, it was created similar to those for mammography; this wrong approach was presented despite of the different physical principles of image acquisition (X-ray absorption laws and ultrasound-wave reflection imaging) which logically result in some different descriptors of the breast findings. Moreover, there were neglected differences between volumic radiological projections in complementary planes of the whole breast by one side and the sectional imaging acquisition in US, with different sizes, shapes, resolutions, and precise anatomical locations of the breast’s normal and abnormal structures.

The contradiction between the applicability of the mammographic BI-RADS assessment, which refers to the management of the diagnosis of whole breast, and the US BI-RADS assessment in the classical examination, which refers to the visualized lesion, neglecting the rest of the breast volume, is the main criticism for its use in the classical US, as it is in present.

The lexicon of the breast was designated by an expert group from the USA and international representatives, in 1998, which was oriented to a breast US screening, to a better differentiation of benign from malignant, and to the use of US as a therapeutic agent or the US-guided therapy. Other groups, in particular Japanese researchers, have contributed to the definition of the US lexicon. By the introduction of the US lexicon and of a standardized protocol of US examination (despite being illogical and inefficient in the variant of the classical US) and by using the US BI-RADS assessment, it was intended to reduce the operator-dependent limit of US; multicentric studies presented promising results both for the experts and for the beginning operators.

Where possible, the same descriptors used for mammography have been transferred to US; these two different methods of diagnosis, based on different laws of physics and addressed to different targets (volume and slice of tissue), were gifted with some similar descriptors of diagnosis, and the confusion will be perpetuated until a new US lexicon will be learned and accepted worldwide. Indeed, the aims of the US BI-RADS lexicon were unsatisfactory, and the fault was attributed to US, as less accurate method of diagnosis, not to the wrong interpreting by using the wrong descriptors. In the following, we will present the values and the limits of this lexicon.

The BI-RADS assessment recognizes some categories unique to the technique of radiology or sonography, however, like echogenicity for US and density for mammography. For US, the main categories for masses are (1) shape; (2) margin; (3) orientation; (4) echo pattern (5); posterior acoustic features; (6) breast calcifications; (7) associated features including architectural distortion, duct changes, vascularity, and elasticity (8); and (9) special cases. These descriptors were evaluated for usage agreement by radiologists at the Society of Breast Imaging 2001 meeting, with good agreement as determined by the kappa statistic [3]; that explains the “radiological” point of view about the ultrasonographic method even in 1003 and 2013 BI-RADS edition and the lack of contribution of independent ultrasonographers.

In the followings, the descriptors, their categories, and associated assessment and management recommendations of the US BI-RADS^® fourth edition will be presented and completed with the Japanese guidelines and the FBU interpretations that highlight the value of the duality vasculature (by Doppler evaluation) and strain (by sonoelastography).

Nevertheless, US BI-RADS is useful and could be improved, and its correlation with sonoelastography was recommended by the World Federation for Ultrasound in Medicine and Biology (WFUMB) [4].

5.2 Ultrasound Diagnostic Criteria

Diagnostic Criteria has been removed by some Japanese authors, and the term Guideline of Ultrasonic Diagnosis is recommended. As a rule, no single feature can be predictive of benign or malignant etiology. Analysis of multiple features together is more accurate in arriving at an assessment.

Classically, the most important descriptors in determining the likelihood of malignancy are the margins and the shape and, secondarily, the orientation, the posterior features, and the echo pattern [5–7]. The microcalcifications, essential in mammography, are mentioned as descriptors in US, but even in the classical US, they are not mentioned in the above list.

In FBU, the most important in determining the likelihood of malignancy are the qualitative Doppler characterization and the sonoelastography, individually (Doppler) or combined. The vascular aspect is neglected in the classical approach, despite its value demonstrated on the pathological reports and on the breast MRI that analyzes the curves of enhancement of the paramagnetic intravenous contrast agents for the final assessment. Sonoelastography was officially launched in 2006, at ECR in Vienna, and the different manufacturers with different techniques of acquisitions and different scoring systems determined an initial discordance of opinions between the specialists about its diagnostic value.

The criteria for assessing breast lesions continue to be validated. For mammography, the “probably benign” lesion, with a reliable management recommendation of short-interval follow-up, has a <2 % likelihood of malignancy.

A similar category for US, the prototype of a fibroadenoma, remains to be validated across multiple centers for US, but the results are significant improved when using the DE.

The new concept that unifies the DE, Doppler, and sonoelastography is not yet very well known, but the complete characterization by US of a lesion, in breast or elsewhere, will not be complete without an anatomical US approach, combined with vascular study and the evaluation of tissues elasticity.

5.3 Lexicon for Breast Lesions

In the lexicon of the US BI-RADS assessment, the classification of the breast diseases in mass image-forming lesions and non-mass image-forming lesions was taken over from mammography [8], but in FBU, we will never find cases from the last category.

For reasons of systematic analysis, we will present the two groups of lesions.

5.3.1 Diagnostic Guidelines for Mass Image-Forming Lesions

5.3.1.1 Shape

Definition: This refers to the impression of shape given from the whole image of a tumor. This is assessed for classification by tumor cross sections [9]:

• Classification: round/oval, polygonal, lobulated, and irregular

• Observations: The impression of shape given from the whole tumor only depends on a judge’s subjectivity, but judging must be more objective referring to a criterion, and the Japanese authors proposed constriction and angularity. Even malignancy can sometimes show a round or oval shape, while benignity can sometimes appear irregular. The major inconvenience of this classification in classical breast US is that there is no correlation of the abnormal US finding with the normal breast parenchyma, ducts, and lobules, and so the eventual imaging lesion may not be a true breast lesion, but a constructed one; that means we are not sure we are seeing a true lesion because we cannot localize it, referring to the lobar anatomy, and we must perform a biopsy. As results in the classical US, either we cannot characterize all lesions or we are characterizing mass “outside” the mammary lobe, or we are missing some, and this is why US accuracy is denied.

5.3.1.2 Margin/Border

Margins are characterized by multiple aspects:

• 1. Definition: well-defined (benign) or not clear (malignant)

• 2. Irregularity: smooth (benign) or rough (malignant)

• 3. Halo: none (benign) or existent (malignant, better seen on sonoelastography)

• 4. Gland surface: continuous (benign) or interrupted (malignant)

These aspects are not really specific as they are assumed, except the halo corresponding to the score 5 Ueno.

5.3.1.3 Internal Echoes

Internal echoes, that is, the echoes from the inside of the mass, are analyzed for judging a lesion and for characterizing it as solid or complex liquid, eventually cysts with fluid-fluid level, with more or less benign or malignant appearance. Internal echoes are analyzed for:

• 1. Intensity (echo level): The echo level of the mass is graded, comparing with that of subcutaneous fatty layer as the standard tissue, having five levels:

  • Echo free (cyst)

  • Very low (sclerosing adenosis, highly homogenous, such as medullary carcinoma and malignant lymphoma; scirrhous carcinoma)

  • Low (fibroadenoma, papilloma, scirrhous carcinoma)

  • Equal (fibroadenoma, mucinous carcinoma, and lipoma)

  • High (mucinous carcinoma, panniculitis, and lipoma)

• 2. Homogeneity: Internal echoes are assessed to be homogeneous (benign) or heterogeneous/inhomogeneous (malignant) according mainly to the regularity in echo distribution or texture.

As a particular aspect, there are described high echo spots, usually representing calcification and divided into three types according to the size: fine (malignant), small (malignant), and coarse (benign) [10]. We agree with Teboul and Amy that in US the microcalcifications are not important for characterizing breast tumors, but they are very important in mammography. US and MRI must not repeat the same descriptors as mammography, but the diagnostic may have different criteria; nevertheless, MRI could not differentiate the calcifications in general from other hyposignals, and the microcalcifications with their inframillimetric size are too small for the MRI scans of more than 1 mm in thickness. In fact FBU has much sensitive signs than the eventually visible “microcalcifications,” which are too large when visible in US for malignant-type calcifications. Indeed, when visualized in US, the microcalcifications are more than 0.5 mm in size, and usually they have no acoustic shadowing, so the images are not specific; frequently, the images judged as microcalcifications in US, which is used as the first technique of examination, appearing as hyperechoic spots, are not seen on mammography, but they could represent the tiny posterior hyperechoic enhancements of microcysts, sometimes completed with lateral shadowing. Inversely, if we analyze a mammogram as the first examination that presents true microcalcifications and then we perform a complementary US, we are tented to “recognize” them (see Chap. 7).

5.3.1.4 Posterior Echoes/Effects

Posterior echoes are one of the findings that indirectly reveal the tissue characteristics inside the mass and depend on the attenuation of the lesions. The intensity of the posterior effects is classified into four levels by means of comparing the surrounding echo intensity at the same depth:

• 1. Accentuating: cyst, fibroadenoma, papilloma, phyllodes tumor, invasive ductal carcinoma (solid-tubular type), medullary carcinoma, mucinous carcinoma, malignant lymphoma, and intracystic carcinoma

• 2. No change: fibroadenoma, adenosis, and invasive ductal carcinoma (papillary-tubular type)

• 3. Attenuating: scar, sclerosing adenosis, invasive ductal carcinoma (scirrhous type), and invasive lobular carcinoma

• 4. Deficient: calcification, old fibroadenoma (with calcification), and silicon granuloma

The mass with high cellularity and cystic lesion tends to accentuate, but mass with abundant fibrous tissue or calcifications tends to attenuate or become deficient [11].

We think that the surrounding tissue has great importance for the intensity of the posterior echoes. For instance, if the hyperechoic glandular stroma is thick, the posterior effects are better visible than in cases with fatty involution of the breast; in such cases, the relation of the lesion with the duct or the TDLUs is the key of diagnosis, and the FBU is the best method to demonstrate it. If the posterior changes are not very well visible, we recommend either a moderate increase of the compression with the transducer on the skin or better the complementary use of THI, which will increase the posterior echo effect.

5.3.1.5 Compressibility

It is admitted that the lesions which are easily deformed are benign, while those incompressible are malignant; this subjective characterization was described by Kobayashi [12, 13] and was recently confirmed by sonoelastography. It is unclear why the subjective compressibility was accepted as descriptor of masses, and sonoelastography was denied by many authors, despite its more objective character.

5.3.1.6 Vascularity

Qualitative color Doppler or equivalents (color flow mode) and power Doppler (uniflow or dual energy) are the unanimous recommendation for the vascular lesion characterization in the breast; there are no vascular or just a hypovascular mapping in benign and a hypervascular mapping in malignant lesions. Quantitative indices of velocimetry are less useful in breast US, compared with other localizations of tumors or tissues, such as the endometrium, ovary, uterine arteries, or musculoskeletal tumors. More important is the vascular orientation toward the tumor, with a peripheral, arcuate course with few centripetal vessels (1–2 vascular poles) in the benign lesions and with multipolar, large, and tortuous vessels, with incident angle of the plunging artery, in the malignant masses [14]. Any less than 5 mm lesions with visible vasculature of any type are suspect for malignancy with the actual US technology.

5.3.1.6.1 Labeling of Breast Ultrasonographic Images

In the classical US as in FBU, breast sonographic examination can show the existence of breast lesions three-dimensionally. Therefore, precise labeling for sonographic images becomes very important and is systematized, in favor of another technique of screening than mammography and of surgical referring. We will present the labeling of those systematized by a Japan group of authors, which is largely accepted [15]:

• I. Labeling for the breast lesion location is made following four attributes:

  • 1. Breast laterality: right or left.

  • 2. Breast quadrant: Inner high/superior, inner low/inferior, outer high/superior.

    Outer low/inferior, beneath the nipple

  • 3. Axis is indicated by o’clock designation (the “meridian/longitude”).

  • 4. Distance of the tumor/lesion from the nipple (“the parallel/latitude”).

• II. Quantitative evaluation of the lesion is made by measurement of the following items:

  $$ \mathrm{Tumor}\ \mathrm{Size}=a\times b\times c\ \left(\mathrm{mm};\mathrm{cm}\right) $$

  (5.1)

In the classical ultrasonographic images, measurement is made in the plane which shows the largest diameter of the lesion: (LDP = largest diameter plane, section A) and a plane perpendicular to LDP (section B).

The detailed process of the measurement is as follows:

• (i) Measure the largest diameter in the section A—line a.

• (ii) Measure the largest diameter perpendicular to line a—line c.

• (iii) Measure the largest diameter in B—line b.

This tumor size is labeled as

$$ V=a\times b\times c $$

In FBU, we will scan logically the lesion first in a radial plane, we will measure the anterior-posterior diameter, which is perpendicular to the thoracic plane (sometimes we cannot use a horizontal plane for the skin), and then we will measure the radial diameter, in the same plan; afterward, we will obtain the section in a antiradial plane, which is perpendicular to the previous described, and we will measure the antiradial diameter, which is orthogonal on the two others achieved. This technique is logical and better standardized, so it can be reproducible and is useful as a follow-up measurement. The volume is automatically calculated by almost all modern machines if there are three orthogonal diameters:

$$ \mathrm{Depth}/\mathrm{Width}\ \mathrm{Ratio}\ \left(D/W\right) $$

(5.2)

In classical US, depth-to-width ratio is measured on the LDP (section A) of the breast lesion. Measurement should be made only for the hypoechoic tumor area, excluding the hyperechoic boundaries. This technique is relatively imprecise and is not reproducible: we can appreciate the largest section of the tumor with inherent subjective errors (slipping hand transducer, different compression because of the different position of the breast against the thoracic wall, etc.).

In FBU we propose the depth-to-width ratio measured either in the radial or in the antiradial plane, with precise mentioning of the plane using the body mark for the breast. We will use the largest diameters, without compression as possible, and we will mention the relation with the ductal axis. D/W is rather <1 in benign lesions and usually ≥1 in the malignant tumors, except for the small fibroadenomas developing from hyperplasic lobules, which have initially a vertical orientation, orthogonal to the skin and to the main duct; then becoming more large, they will change the orientation in an oblique position; and finally, when they have developed sufficiently, their long axis will course parallel to the skin.

5.3.2 Diagnostic Guidelines for Non-mass Image-Forming Lesions

There is also a diagnostic guideline for non-mass image-forming lesions by the Japan Association of Breast and Thyroid Sonology (JABTS) and Japan Society of Ultrasonics in Medicine, which is concordant with the American guidelines and refers to “the lesions that are difficult to recognize as ‘mass image-forming lesions’,” which may exist separately or may associate with them [8]. These guidelines offer few characterizations about these so-called non-mass image-forming lesion, but they suggest that in classical US, similar to mammography, there are cancers not visualized per primam; therefore, it is proved that after breast MRI lesion identification and localization, US is useful in the characterization of its risk of malignity, so the initial “not-mass image-forming” lesion becomes visible on US, which means that it is not the US that is unable to visualize some lesions but the classical technique unsatisfactory in detecting them. We agree with Amy that in FBU, we never had a “not-mass image-forming” lesion, because the interpreting is better, so if a small abnormality, equal or larger than a duct or lobule, is present, FBU is able to detect by everyone. The problem remains in DE in the diagnosis of lobar carcinoma and of carcinomatous mastitis, but sonoelastography added supplementary information that could differentiate them from diffuse hyperplasia or infectious mastitis (see Chap. 8).

However, this last guideline is useful because it describes some lesions such as duct thickening, duct ectasia (contains plasma cell mastitis), intraductal papilloma, and others; unfortunately, it still multiplies the mammographic incertitudes, such as architectural distortion, which is the distortion and/or retraction of the normal tissue inside and/or outside of the breast tissue, low echo area whose character is different from surrounding gland or suitable area in the opposite breast, and geographical low echo area. All these descriptions and more others are tentative to eliminate the false-negative results in classical breast US, but they are unsuccessful because of a nonanatomical approach and thus a non-understanding of the breast structure. For instance, it is not explained what the normal tissue and the breast tissue mean; the term surrounding gland is vague, as well as geographical low echo area, because there is no correlation with the mammary lobe or with the ductal-lobular tree, so the location of these non-mass image-forming lesions is imprecise. Moreover, these lesions are still forming some images, but without mass aspect, that means without tridimensional coordinates; these suspect lesions are visualized only as representations in a plane, which is obtained arbitrarily in classical US examination; then how could it be compared with a suitable area in the opposite breast?

By using FBU, the interpretation of the breast will allow an anatomical analysis:

• The description of the type of the normal breast: young, adult, fatty, mixed, and lactating/secretory; glandular stroma and global vasculature must be mentioned.

• The description of the normal ducts and lobules for each case, related to the age, menstrual cycle or substitution hormonal therapy, constitutional factors, nutrition, etc.

• The description of the abnormal findings related to the breast parenchyma or other structures: localization type in o’clock completed with the distance from the nipple (the “coordinates”), number (multifocality), rapports with the surrounding structures (Cooper ligaments, fatty layers, pectoral muscles, skin—the description of the rapports is missing in the classical US guidelines), and all the known descriptors of a lesion (shape, border, internal echoes, posterior echoes, vascularity, elasticity).

In FBU we will use only anatomical or pathological terms, and we will never use confusing terms such as low echo area with indistinct margin, because they are not useful for the clinicians, surgeons, or oncologists and especially because these images are not reproducible for different operators.

5.3.3 Ultrasound BI-RADS Assessment

ACR BI-RADS–US describes seven assessment categories of lesions. One category is for lesions that are incompletely characterized, and for which, further imaging is needed for final assessment. The six other assessment categories have implications on patient care.

Because the dense breast is difficult to diagnose on mammography, there is a classification of the glandular density that is important for the dose of radiation and for the quality of the images, implied in the accuracy of diagnosis. This model was transferred in US diagnosis, but we mention that in US, the anatomy and the pathological findings in the “dense breast” (improper term for the “predominantly glandular breast”) are better viewed than in the fatty breast, because the malignancies and most of the benign lesions are izo- or hypoechoic and thus are difficult to differentiate from the fatty layers.

There may be two methods of US BI-RADS density categorization:

• 1. Qualitative-descriptive:

  • Predominantly fat

  • Fat with some fibroglandular tissue

  • Heterogeneously dense

  • Extremely dense

• 2. Quantitative, fraction of volume occupied by fibroglandular density:

  • 0–25 %

  • 26–50 %

  • 51–75 %

  • 76–100 %

In both categorizations, the evaluation is subjective and operator dependent; the so-called quantitative evaluation is not the result of some measurements, neither an evaluation specific to the US, because the scans may overlap some areas and omit other regions of the breast; in all cases, the scans are different according to the quadrant, asymmetry, and heterogeneity, the inner ones being more fatty and the outer more glandular in texture. In fact, the US breast density categorization is an imitation of the mammographic assessment that is justified by the whole breast standardized projection and by reasons of technical and electrical parameters of acquisitions and of radiological interpreting of mammograms.

5.3.3.1 US BI-RADS Assessment by the ACR (2013)

5.3.3.1.1 Incomplete Characterization

• Category 0—Supplementary imagistic evaluation required

  • Examples: Supplementary mammography when suspect FBU (for microcalcifications); MRI when US is inconclusive for the differentiation of the local recurrence from a scar following conservative breast surgery or radiotherapy; MRI in suspect multifocal/multicentric or diffuse lobar cancer.

5.3.3.1.2 Complete Characterization

• Category 1—Negative

  • ACR: Normal breast US, without any abnormalities such as masses, architectural distortions, skin alterations, microcalcifications, and pathological lymph nodes

  • FBU: Normal breast US, without any abnormalities such as masses, ductal ectasias, ductal or lobular hyperplasias, pathological vasculature or pathological strain, skin alterations, scars, and pathological lymph nodes

• Category 2—Benign aspects

  • ACR, US without any suspect lesions, but benign findings: follow-up after conservative surgery, intramammary lymph nodes (they could be included in the category 1), mammary implants, architectural distortions, oil cysts, lipomas, galactoceles, and hamartomas.

  • In FBU we can add ductal and lobular hyperplasia without suspect vasculature, ductal ectasia, and ductal and lobular precocious atrophy (Fig. 5.1).

    Fig. 5.1

    

    Benign-type breast lump in a 25-year-old patient, with less salient vasculature and SE of score 2 Ueno; the US BI-RADS assessment is category 2

• Category 3—Probable benign findings

  • ACR: A short-interval control is recommended rather than biopsy; there is a malignancy risk less than 2 %. The following are included: solid masses with circumscribed limits, ovoid shaped with the great horizontal axes, suggestive for fibroadenoma, but inhomogeneous or with more than three microlobulations; less complicated cysts or the grouped microcysts (cluster).

  • In FBU we can add intraductal and intracystic papillomas, ductal-lobular hyperplasia in postmenopausal women or after hormonal therapy, ductal ectasia with bloody nipple discharge, and nodular fibro-micro-cystic dysplasia with less vasculature but increased strain.

• Category 4—Suspicious abnormalities

  • ACR: Biopsy is largely recommended; there is a variable risk for cancer, between 4–94 %. The large interval of risk requires a subdivision in low, moderate, and high risk, corresponding to 4a, 4b, and 4c categories. The following are included: the US masses without all criteria of benignity/malignity, the phyllodes tumor, and other suspected findings. In case of one or two criteria of malignancy, the biopsy is classically recommended [16].

  • FBU: The suspect lesions will present suspect/malignant-type vasculature, with borderline or suspect sonoelastography of score 3 or 4 Ueno and FLR around 4.00–6.00. The satellite lymph nodes are still of “benign” aspect.

• Category 5—Highly suggestive of malignancy

  • ACR: The risk of malignity is evaluated over 95 %; the Stavros criteria in the classical US are demonstrated, or there is a vasculature with malignant characters. The biopsy and immediate treatment is recommended.

  • More accurate, the FBU combines the classical features of malignity with Doppler malignant-type new vasculature and sonoelastography, with the score 5 Ueno and FLR over 4.70 (5.00); the satellite lymph nodes could be still of “benign” aspect or suggesting for metastases. The intraductal dissemination with multifocal lesions, the multicentric suspect findings, the lobar cancer, and the malignant mastitis are assessed as US BI-RADS 5 category. FBU is more accurate, and the biopsy could be avoided for the BI-RADS 4 and 5 categories when surgical biopsy is recommended in small lesions, with extemporaneous pathological examination; in large lesions, the immunohistochemical and hormonal tests are suitable for the treatment protocol.

• Category 6—Biopsy is performed; malignancy is demonstrated.

  • An immediate therapeutic action is recommended. The US examination can be requested for a follow-up evaluation of an initial chemotherapy or neoadjuvant radiotherapy or after incomplete excision (Fig. 5.2)

    Fig. 5.2

    

    Malignant-type lump in a 56-year-old patient, with similar features in 2D US, but with salient new formation vasculature in medium-resolution (7 MHz) transducer and with score 5 Ueno, assessed as US BI-RADS 5 category