X-rays, ultrasounds, mammograms: What medical images do they reveal?

We hear of terms like X-ray, ultrasound, MRI and mammography all the time, but do we actually know what they mean? And what they're for?

Whether it's for you or a loved one, here is a useful guide to the most common diagnostic tests so that you understand more their meaning and their purpose.


X-rays are electromagnetic waves with the ability to travel through organic matter. As the waves pass through the body, they are absorbed by it, depending on the matter's density. Those that are not absorbed leave the body and are printed on a sheet with photographic qualities, creating a black, white and grey photograph of the body.

- What are x-rays used for? X-rays are taken to get images of the internal structures such as organs, tissues or bones. They are very useful in the diagnosis of bone fractures, inflammations, internal bleeding, infections or even tumours.

- When not to use them: During pregnancy, X-rays are not recommended. They are, in fact, strongly discouraged. The radiation can be harmful to the foetus, the reproductive system and other tissue.

Ultrasound Scans

This test is based on sending high frequency sound waves into the body. These waves send back echoes, which are analysed by a computer and projected onto a monitor. The ultrasound scan is a safe test; it can be performed anywhere on the body without any harmful effect.

- What is an ultrasound test used for? All kinds of organic abnormalities can be investigated through this method. It is very useful in obstetrics to analyse foetal development as well as the diagnosis of tumours, internal bleeding, cysts and inflammations. This scan also spots fluid-filled injuries with amazing clarity.

Magnetic Resonance Imaging (MRI)

An MRI is based on the use of a high-intensity magnetic field that surrounds the body and provides pictures of the analysed organs and tissues.

- What is it used for? The MRI is considered a more sensitive imaging test than an X-ray, since it permits better analysis and definition of the soft tissues from various angles.

- What kind of data does it provide? It is very useful to investigate the central nervous system, as well as tumours, internal bleeding, vascular anomalies, brain strokes, ulcers and many other diseases. The MRI is the best method to diagnose slipped disks in the spinal cord. It has also proved to be very effective in sports injuries involving muscles or joints. However, it can be disconcerting for claustrophobic patients. In this case they should be tested with open air equipment.


Based on the same process as an X-ray, a mammography is aimed specifically at breast analysis. It is taken with X-ray equipment called a mammogram.

- What is it used for? Mammography is very useful for prevention and early diagnosis of breast tumours.

- What kind of data does it provide? It is essential in the diagnosis of cysts, small tumours, fibroids and breast cancer. As the radiological images are taken with different sizes and angles, the small anomalies in the tissue become very clear and obvious.