Authors: Kinga Karlinger, Erika Márton
2. PET, SPECT, PET/CT:
The basics of breast PET/CT diagnostics are based on the change in the metabolic activity of tumor tissue, represented by increased glucose metabolism of malignant cells. FDG (18F-deoxi-glucose) is used as radiopharmacon.
Indications:
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Limitations:
3. Marking of small, non-palpable lesions before surgery.
4. Marking of sentinel lymph nodes.
12.2.2.5. Interventions in breast imaging
• Pneumocystography: In certain cases (e.g.: dense cysts or cysts with septations) after cystic drainage the cystic cavity is inflated with air in order to rule out intracystic tumors.
• Galacto- or Ductogrpahy: (Picture 4,5) is an examination that requires contrast material. It is indicated in breast bleeding or discharge, performed after
mammography, ultrasound examination and cytological aspiration have all been carried out. The ducts are injected with contrast material which then either can reveal intraductal lesions causing sharp, margined filling defects, distortions or complete obstructions in the duct.
Picture 4. Picture 5.
• Targeted biopsies:
1. Cytologic aspirations: fine needle aspiration biopsy (FNAB)(Picture 6., 7., 8., 9.) 2. Histologic biopsy: core (tissue column) biopsy (CTB):
o Automatic gun biopsy sampling, guiding: US or X-ray o Stereotaxic Vacuum Core biopsy: Mammotome (sVCB)
The majority of pathologic lesions are detectable with ultrasound, therefore US is a major guiding tool. In other cases (e.g.: in case of apparent microcalcifications only) X-ray guided stereotaxic (3D) or the so called compression hole plate (2D) guidance are available. In case of lesions only detectable with MRI of course MRI guided biopsy is the only method of choice.
147 Picture 6. Picture 7.
Picture 8 Picture 9.
• Localization methods:
1. Preoperative localization: (Picture 10.) Indication:
o Small, non-palpable tumor localization might be necessary in order to ensure optimal tissue excision.
The localization can be made with:
- usually with a steel wire (hook wire or guide wire) localization. Guidance: US or X-ray.
- sometimes with an isotope (technetium-99m labeled nanocolloid). Detection with a scintigraphy probe during surgery (ROLL technique).
o Sentinel lymph node biopsy: the goal is to remove and analyze the most likely site for lymph node metastasis and to avoid unnecessary ABD (axillary block dissection) and to avoid its complications.
Markers can be:
- dye (methylen blue)
- isotope labeled nanocolloid, detected by gamma probe
- the combination of the above mentioned two methods (most precise)
o Tumor and the sentinel lymph node can be marked together: with the administration of a small and large molecule isotope labeled colloid
Localization confirmation can be performed with: specimen mammography (=mammogram taken of the removed breast part) (Picture11.)
Picture 10. Picture 11.
12.3. The anatomy of the breast
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The breast is made up of glandular tissue, fat, connective tissue and blood vessels. The composition ratio of these elements change over the age.
The glandular tissue is made up of 15-20 lobes, each of them opening with a proper duct at the nipple.
The smallest unit is terminal ductal lobular unit (TDLU = extra- and intralobular ductal parts – acini) (Picture 12.)
Many types of normal breast variants exist on mammography. The 5 most common types have been described by Tabár by his classification system: I. Young, Fibro-glandular, II.
Completely involuted, III. Transient type between I. and II., IV. Adenotic V. Fibrotic.
Picture 12.
12.4. Radiologic appearance of pathologic lesions of the breast
Pathologic lesions in the breast appear as various shapes and densities of soft tissues or calcificications or as the combinations of these two on mammography (Picture 16.). At many times only a few scattered, ill-defined, pleiomorphic microcalcifications indicate the presence of a pathologic lesion.
The soft-tissue lesions can appear as well-defined, rounded or oval shaped (Pictures 13.,14.) or as ill-defined, star-shaped masses (Picture 15.). Rounded or oval lesions are in most cases benign and their malignant proliferation is rare, they do not require surgical removal. These lesions are usually cysts and fibroadenomas, at other times harmartomas, lipomas and at very few times malignant tumors.
Ultrasonography can help in their differentiation; can depict anechoic cystic lesions (Picture17.) or solid masses (Picture 18.). These lesions usually each have a smooth, sharp edge and echo-enhancement can appear behind them. Rarely, cysts contain tumors.
(Picture19.).
Ill-defined margins, with uneven contours and blurred edges are usually characteristic of malignant lesions. During ultrasound examination echo-attenuation occurs frequently behind these inhomogeneous hypo-echogenic masses (Picture 20).
Star-shaped lesions are very typical of malignant tumors.
o ―White star‖: describes the tumor body with dense spiculations of various lengths appearing around the core = carcinoma
o ―Black star‖: there is no tumor body, the central part is transparent. The spiculations are arched, long and thin. These usually do not indicate the entity of the lesion; they can either be benign or malignant. Examples are lobular carcinoma, post-radiation scar tissue, fatty necrosis or postoperative scar tissue (patient history is indicative!).
149 Picture 13. Picture 14. Picture 15. Picture 16.
Picture 17. Picture 18 Picture 19 Picture 20.
Calcifications appearing in the breast:
Calcifications usually occur in the secretions or in the necrotic parts of the lesions, but they can also be found within the arterial walls or old hematomas as well as scar tissues. (Picture 22.)
Calcifications are encountered in the breast quite often. Most of them accompany benign process (Picture 21.) and only a smaller percentage actually indicates malignancy. These malignant signs are basically always micro-calcifications. They are ill-shaped, with various pleomorphism (Pictures 23.,24.) and they are usually show a clustered arrangement. Their number is irrelevant to the grade of malignancy. Differential diagnosis is usually hard, if not impossible with mammography only, but targeted and magnified images can help in their analysis. The solution for differential diagnostics is biopsy.
Picture 21. Picture 22. Picture 23. Picture 24 12.5. The operated breast
Operated breast most commonly is a result of a therapeutic solution of a malignant lesion (e.g.: mastectomy, breast conserving operations, or after reconstructive surgery). At other times cosmetic reasons (plastic surgery) lead to the state of operated breast. Operated breasts are always to be examined, controlled by the radiologist and the imaging modality is always to be adjusted to the current situation with determined protocols.
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12.6. Male breast examinations
Breast cancer ratio is relatively rare in males compared to females, about 1:100. The
morphologic appearance is similar to that of the female breast and the imaging process is the same as well. Physical examination due to the smaller size of breast is usually more indicative in males.
A quite common breast alteration at childhood or adolescence is gynecomastia (Pictures 25.,26.), when the retro-mammillary region shows increase in the glandular tissue. Imaging methods: in adolescence breast ultrasound alone is enough to be performed. Mammography together with ultrasonography is performed above 30 years of age. In certain cases breast biopsy can be indicated. Surgery is only necessary in cases of malignancy and for cosmetic reasons.
Picture 25. Picture 26.
12.7. Summary
The recent developments in breast imaging methods, the appearance of new technologies and the wide-spread availability of breast cancer screening have lead to the emergence of
―increasedly invasive breast diagnostics‖. Nowadays, it is essential to organize and centralize these different diagnostic methods. Breast imaging has become a team-work, which requires tight co-operation of all its participants (radiologists, cyto-histopathologists, surgeons, oncologists and radiotherapists.) All of these factors together provide the chance to significantly decrease the mortality of breast cancer. In order to provide a more organized workflow of the subspecialties and a more comparable reporting system, each method of the complex clinical breast imaging diagnostics currently use the same coding terminology, developed by the American College of Radiology (ACR). This is the so called BI-RADS code and is an organized and internationally recognized system that appears in all radiological reports and is in very close relation to the pathology reports.
BI-RADS coding *
0 Incomplete examination (additional imaging is needed) 1 Negative
2 Benign
3 Probably benign: short term, (6 moths) follow up or biopsy is needed (chance for malignancy 2%)
4 Suspicious for malignancy: biopsy is necessary (chance for malignancy 2-94%) 5 Highly suggestive of malignancy (95%>): requires adequate therapy
"*" Breast Imaging-Reporting and Data System
151 12.8. References:
László Tabár: Teaching Course of Mammography
Diagnosis and in-depth differential diagnosis of breast diseases
G. Forrai: The radiologic and therapeutic novelties of breast cancer in 2008-2009. – Onco Update 2010 Magyar Radiológia 2010;84(1): 8-21
Z. Péntek, K.Ormándi: Mammography breast screening, the clinical diagnostic results of patients positive on screening. A quality assurance and quality management protocol.
http://www.socrad.hu Translated by Balázs Futácsi
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