Breast cancer other imaging studies
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Soroush Seifirad, M.D.[2]
Overview
Other diagnostic studies for breast cancer include modified MRI utilities (high-field strength MRI, magnetic resonance spectroscopy, and diffusion weighted imaging, breast-specific gamma imaging, positron emission mammography, scintimammography, thermography and bone scan.
Scintimammography or breast-specific gamma imaging (BSGI)
- Gamma cameras with 2 to 3 mm in-plane resolution in a mammographic configuration are used
- Concept of BSGI is based on the accumulation of technetium-99m sestamibi in intracellular mitochondria of breast cancers cells.
- Compared to normal cells there is an increased number if intracellular mitochondria in breast cancer cells.
- Procedure
- First 25 mCi of technetium-99m sestamibi is being injected intravenously
- Following the injection of the radioisotope, The patient is scanned for 5 to 10 minutes.
- Mild breast compression is applied as of conventional mammography.
- Craniocaudal and mediolateral oblique views for each breast
- This is an adjuvant imaging method and hence images will be interpreted with respect to the patient's mammograms, ultrasounds, and clinical findings.
- If indicated, BSGI compatible biopsy system is available to direct tissue sampling for the patients with small lesions not seen on other imaging modalities.
- Compared to MRI, BSGI showed an equal sensitivity and higher specificity for the detection of breast cancer.
- BSGI is recommended for use in the preoperative assessment of disease extension in breast cancer patients. or:
- To check breast lumps that do not show up clearly on a mammogram because of:
- Scar tissue from previous surgery or radiation therapy
- Dense breast tissue
- Breast implants
- When multiple tumors are seen in the breast
- To scan the lymph nodes in the armpit (axilla) to see if they contain cancer
- Because of a very limited available DATA at the moment, BSGI is not recommended for screening or as a tool to exclude the likelihood of malignancy in suspicious breast masses or abnormal mammography.
Bone Scan
- A bone scan uses bone-seeking radioactive materials (radiopharmaceuticals) and a computer to create a picture of the bones. It is used to see if breast cancer has spread (metastasized) to the bones.
- A bone scan may be done if:
- Alkaline phosphatase in the blood is increased
- There are lymph nodes in the armpit (axillary lymph nodes) that can be felt
- The primary breast tumor is larger than 5 cm
- The woman has aches and pains that may be caused by bone metastases
- A bone scan is not done in women who have stage I breast cancer.
Thermography
- Digital infrared thermal imaging (DITI) is a type of thermography which is used in the screening of breast cancer
- An infrared thermal camera takes pictures of the areas of different temperature in the breasts.
- The camera displays these patterns as a sort of heat map.
- Since the presence of cancerous growth is associated with the excessive formation of blood vessels and inflammation in the breast tissue.
- On the infrared images, these higher temperatures could be detected.
Benefits
- Non-invasive procedure
- Non-contact procedure (does not compress the breast)
- No exposure to radiation, (safe)
- It can detect vascular changes in breast tissue associated with breast cancer many years in advance of other methods of screening.
- It can be used for all women, including those with dense breast tissue and breast implants.
- Hormonal changes do not affect results.
Drawbacks
- High false-positive rate
- High false-negative rate
- Rarely covered by medical insurance
- The high false-positive and false-negative rates associated with thermography often mean that the woman will need a standard mammogram anyway.
Positron emission mammography
- PEM is still under investigation.
- High-resolution fluorodeoxyglucose PEM with compression with 2 mm in-plane resolution has been studied for detection of small malignancies
- The procedure
- This is a modified PET scan method and hence patients are prepared as for PET scan.
- Mild compression as of conventional mammography
- Craniocaudal and mediolateral oblique views for each breast
- This is an adjuvant imaging method and hence images will be interpreted with respect to the patient's mammograms, ultrasounds, and clinical findings.
- if indicated, PEM-compatible biopsy system is available to direct tissue sampling for the patients with small lesions not seen on other imaging modalities.
- Sensitivity 86 to 91 percent
- Specificity91 to 93 percent
- Major drawback is that PEM cannot reliably detect low-grade malignancies.
- Hence, PEM is not recommended for screening or as a tool to exclude the likelihood of malignancy in suspicious breast masses or abnormal mammography.
- Nevertheless PEM is promising for the preoperative assessment of disease extension
