by Breast Imaging: Techniques For Early Detection
Breast imaging refers to the medical imaging techniques used to visualize the breasts for diagnostic and screening purposes. Advanced breast imaging technologies help physicians detect abnormalities in the breasts at very early stages, facilitating timely intervention and management.
Mammography
Mammography is considered the gold standard breast cancer screening tool. A mammogram generates X-ray images of the breasts that can detect tumors that are too small to feel. During a mammogram, the breast is compressed between two plates which spreads out the breast tissue to produce clear images. Both breasts are imaged from top to bottom and from side to side views to find any abnormalities. Digital mammography provides higher quality images compared to conventional mammograms. 3D tomosynthesis is an advanced type of mammography that takes multiple images from different angles to create a 3D view of the breasts. This helps distinguish overlapping tissues and improves cancer detection rates.
Breast Ultrasound
Breast ultrasound uses high frequency sound waves to produce images of the breast tissues and structures. It is useful for further evaluating lesions detected on a mammogram or a lump felt by the patient or doctor. Ultrasound provides a live moving image of the breast unlike static mammograms. It can distinguish between solid masses which may be cancerous from fluid-filled cysts which are usually benign. Ultrasound is also used to guide breast biopsies. 3D breast ultrasound or automated whole breast ultrasound allows radiologists to view the entire breast in real time.
Breast MRI
Magnetic resonance imaging (MRI) of the breasts generates very detailed images using powerful magnets and radiofrequency pulses. Breast MRI has high sensitivity in detecting cancers, especially in women with dense breasts where masses are difficult to visualize on mammograms. It is helpful in screening women at high risk for breast cancer. MRI is also used when mammograms or ultrasound findings need further clarification or staging of breast cancer is required before surgery. However, breast MRI has lower specificity compared to mammography resulting in more false positive findings. It is also more expensive.
Molecular Breast Imaging
Molecular Breast Imaging (MBI) or scintimammography uses gamma cameras and radiotracer injections to visualize molecular activity within breast tissues. The radiotracer, typically technetium-99m sestamibi, accumulates more in malignant cells compared to benign or normal tissues. MBI provides functional information and allows detection of small cancer deposits not seen on other imaging tests. However, availability of this technique is currently limited.
PET/CT imaging
Positron emission tomography combined with computed tomography (PET/CT) utilizes radioactive tracers like fluorodeoxyglucose (FDG) to identify malignant cells based on their increased sugar metabolism. PET/CT plays a role in staging of breast cancers, detecting metastases, and guiding biopsy of suspicious areas on conventional imaging which require tissue confirmation. It can help monitor treatment response as well. However, the use of ionizing radiation and limited availability restrict its routine screening use.
Role of imaging biomarkers
Beyond the anatomical information, recent advances in breast imaging focus on extracting quantitative biomarkers from images using computer-aided diagnosis techniques. Texture analysis of lesions on ultrasound or MRI may help predict the aggressiveness of cancers. Kinetic enhancement curves from contrast-enhanced MRI providing functional information on microvessel permeability and cellularity is being studied to improve detection and characterization of tumors. Radiogenomics combines imaging phenotypes with gene signatures for personalized breast cancer management.
Emerging techniques
Some novel breast imaging modalities under research include diffuse optical tomography using near-infrared light, elastography assessing tissue stiffness, thermography measuring surface temperature variations, and optical coherence tomography providing high resolution cross-sectional views. Fusion of functional information from these techniques with anatomical data promises enhanced tumour characterization and detection of premalignant lesions. Automation and artificial intelligence in analysing large imaging datasets also holds promise for improving breast cancer screening outcomes.
Breast imaging integrates conventional modalities like mammography, ultrasound and emerging ones like MRI and molecular techniques to provide both anatomical and physiological information crucial for optimal breast health screening and management. A judicious combination of tests tailored to individual risk factors helps achieve early and accurate diagnosis. With continuous technological advancements, breast imaging will likely play an increasingly important role in the fight against breast cancer.
*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
