Breast Unit: Understanding my scans

Your specialist will decide the appropriate scan to guide further assessment after taking a short history and performing a clinical examination.


Mammogram is a breast X-ray and is the standard method of imaging for patients above the age of 40. Your breasts will be placed individually on the x-ray machine. The breast will be pressed down firmly on the surface by a clear plate. At least two pictures of each breast will be taken, one from top to bottom and then a second from side to side to include the part of your breast that extends into your armpit. You will need to stay in this position while the x-ray is taken.

You may find this process uncomfortable, but the compression does not harm your breast tissue and lasts only a few seconds. Please inform us if you had a mammogram within the last 12 months as you may not need a repeat mammogram if you had one in the last year. A mammogram is a useful tool for diagnosing breast disease is it can check the whole of both breasts and allow the radiologist to compare left with right as well as comparing with previous mammograms. It is therefore a key investigation for a number of women.

Ultrasound scan

An Ultrasound scan is another type of scan your specialist might decide that you need. This is typically a targeted scan to check an area of concern in more detail. This will be performed by one of our experienced radiologists. To help gain a clear image of the breast, some gel will firstly be spread over a targeted area in the breast. The radiologist doing the scan will move a handheld scanning probe over the breast to look at the underlying tissue. The area under your arm (axilla) may also be scanned. The advantage of ultrasound is that it can be used in younger patients and in patients above the age of 40 it can be used as another mode of imaging with mammograms.


Magnetic resonance imaging (MRI) is only used in certain circumstances, typically in the diagnosis of specific forms of breast cancer, when planning complex surgery and when breast cancer cannot be adequately visualised with other imaging types. The consultant radiologist will advise as to whether a MRI is required. MRI is a very sensitive test and frequently identifies areas of the breast that require further investigation such as "second-look ultrasound" or further biopsies.

CT scan

Computerised tomography (CT) scans are rarely used in the initial diagnosis of breast cancer. However, sometimes a patient has a CT scan for another reason, which detects an abnormality in the breast incidentally. In these cases, the doctor who organised the first scan may refer the patient to the Breast Unit for clinical examination and mammograms or ultrasound scan as necessary.

A CT scan is sometimes useful after breast cancer has been diagnosed to look for any breast cancer deposits (metastases) elsewhere in the body. This is usually requested on the advice of the oncologists.

Bone scan

A bone scan is occasionally performed to rule out any bony metastasis if there is suspicion of a bony finding on CT scan.