Mammography is a breast radiography which is using low doses of X-rays. It is the main method used in the diagnosis of breast lesions and the only imaging technique widely used for breast cancer screening. The examination has a sensitivity of approximately 90%, in other words 10% of breast neoplasms are occult, mammographic undetectable. Mammographic detectability of breast cancer depends on tumor size, type of growth, histopathological subtype and breast parenchyma adjacent to the lesion. The overall sensitivity of mammography is excellent in fat tissue and low in the dense, glandular tissue of the breast. This explains the results of studies which reveal that 9% of palpable cancers are also undetectable by this imaging technique.
Because mammography is the projection of all the images from all the breast parts, cancer will be more difficult to detect in a breast with dense tissue( opaque ), especially if there is no indirect signs to attract attention to a malignancy ( architectural distortion or microcalcifications). Due to these variations in a normal mammographic appearance, over time various classifications of the breast types have been tried. Today`s accepted classification is published by The American College of Radiology, “Breast Imaging Reporting” and “The Data System ( ACR, BI-RADS )”, which describes four types of normal breast, numbered 1-4:
- Predominantly fat ( < 25 % glandular tissue ) ACR = 1
- Glandular dispersed (25 % – 50 % glandular tissue ) ACR = 2
- Heterogeneously dense (51% – 75 % glandular tissue ) = ACR 3
- Very dense ( > 75 % glandular tissue ) ACR = 4
The significance of this classification is to alert the clinician to the fact that in a dense breast, the ability of mammography to detect a small cancer is reduced. Given the high number of breast cancer, early diagnosis is a very important matter. The discovery of breast neoplasms in the early stages is essential for therapeutic success.
Over the age of 40 years as a screening method for detecting breast cancer an annual mammography exam is recommended as a first intention examination to detect palpable masses in women over the age of 35 years. Under the age of 35 years, beside the first intention examination a mammography is needed in these particular situations.
- Symptomatic patients with negative ultrasound examination ( palpable lesions , suspicious nipple discharge , retractions or skin and / or nipple thickening, nipple eczema )
- Patients under 35 with a family history of breast cancer at a young age or other risk factors linked to the existence of genetic mutations,
- Ultrasonographic finding of a suspicious lesions
- Ultrasound discovery of changes suggestive of malignancy characters
- Ultrasound detection of suspicious microcalcifications or the possibility of their existence,
- Inconclusive ultrasound examination in case of fat tissue breast ( over the age of 30 years ).
Mammography is currently considered the most demanding radiological examination. The device itself and the examination should have certain necessary qualities for a correct and complete diagnosis.
Breast compression is necessary for several reasons. Compression reduces motion artifacts, decreases breast thickness with significant reduction of the dose of irradiation, a uniform optical density is obtain and by reducing breast -film distance the geometric “flow “ is reduced. To avoid discomfort due to premenstrual swelling and compression swelling the examination is performed preferably in the first period of the menstrual cycle.
- Standard incidents
As standard two exposures are made for each breast , medio- lateral oblique incidence (MLO ) , the most important, allowing an almost complete breast gland analysis and cranio- caudal (CC ) which allows a better appreciation of internal quadrants
- Additional incidents
Additional incidents (strict profile, tangential, Cleopatra, external exaggerated, internal exaggerated, axillary) is recommended for a better appreciation of the morphology of detected lesions, their precise location and for artifactual elimination.
Tracked mammographic parameters:
- Structure or breast density
- Volume symmetry and size
- Presence of :
- Nodular opacity
- A focal or diffuse density
- An architectural distortion
- A micro- or macro-calcifications
- Mixed picture
- Perilesional and distance changes
To assess the stability or changes detected, performed mammography examinations are compared to previous examinations (stability is a criterion of benign lesions).