CT (CAT) SCAN, MRI

These provide detailed images of the inside of the body, and are very beneficial when a person shows signs of a particular disease or condition. If disease is present, these scans can help in determining the extent of the disease and in monitoring the effects of treatment.

However, if a person has no symptoms of illnesses, there is no evidence to suggest that CT scans or MRI will detect a disease earlier than traditional methods, alter the outcome of disease in any beneficial way or prevent premature death. Thus, regular scans are not advised. If you have symptoms of disease, do consult your doctors - they will determine if any specific diagnostic tests are required.

How it's done: CT scans and MRIs are painless, but you need to lie very still on a special bed while an X-ray machine scans a particular part of your body.

ULTRASOUND

Ultrasound is used to obtain an image of an internal body structure for diagnostic purposes or to monitor a developing foetus in the womb.

How it's done: A clear gel is applied to the area being scanned to help the transducer (a device that translates one form of energy to another) to make secure contact with the body. The sonographer (ultrasound technologist) then presses the transducer firmly against the skin and sweeps it back and forth. Ultrasound is usually painless.

COLONOSCOPY
This examines the inner surface of the colon with a colonoscope.

How it's done: You need to empty your bowels in preparation for the test - the doctor will advise a liquid diet one to three days before the procedure and a laxative the night before.

During the scope, there may be mild cramping, bloating or a feeling of having gas - this is usually from the gas pumped in to expand the colon and make it easier to see the lining. Medication can be given to minimise discomfort.

GASTROSCOPY

Upper Gl endoscopy, otherwise known as gastroscopy, is used to evaluate disorders of the oesophagus, stomach and the duodenum. Symptoms such as recurrent or persistent upper abdominal pain lasting several weeks or more, heartburn, acid regurgitation, difficulty or pain in swallowing suggest disorders of the upper digestive tract and are indications for upper Gl endoscopy.

Certain symptoms are considered "red flags" and should prompt early evaluation. Examples include unexplained weight loss, difficulty in swallowing, anaemia and a positive family history of stomach cancer.

How it's done: It involves passing an endoscope, which is a small-calibre flexible tube with a camera lens and light source at its tip, through the mouth into the upper digestive tract. With the camera lens, it is possible to view and record the internal appearance of the upper digestive tract.

BREAST SCREENING

Singapore is the only Asian country with a nation-wide breast cancer screening programme launched in 2002. The BreastScreen Singapore programme recommends that all women 40 years old and above go for regular mammograms. Those 40-49 years should do it annually while those above 50 years, once in every two years.

There have been recent reports of doing an ultrasound of the breast in addition to mammography as this has been shown to increase the rate of detecting cancers.

Due to the improvement in ultrasound technology, many small lesions (that are often harmless) can also be detected. This may then result in an increase in anxiety for women. In addition, doing an ultrasound would add to the cost of screening.

For high-risk young women, recent studies suggest that MRI is useful in detecting early breast cancer.
However, as MRI is costly and thus not widely affordable, so do check with your doctor as to what the most suitable screening method is for you.

How it's done: Mammograms, also mammography, involve some radiation, but the exposure is minimal. The technologist positions the breast between two plates to enable pictures to be taken of each breast.

Contrributed by Dr Tan Su-Ming, Changi General Hospital; Dr Ang Tiing Leong, Changi General Hospital; and Dr Chan Lai Peng, Consultant, Singapore General Hospital

This article was first published in SingHealth's AllWoman! magazine. For more stories on women's health, visit www.singhealth.com.sg