General Medicine
The Annual Health Check: What Is Worth Testing
A useful yearly check is six or seven cheap tests, not a fifty-test package. What to ask for at each age, what to skip, and how to read the report.
30 Aug 202610 min read
Ultrasound
Also known as Sonography, Ultrasound scan, USG
An ultrasound scan builds images from high-frequency sound waves reflected back off the body's tissues. It uses no radiation, which is why it is the scan used in pregnancy.
A probe emits sound far above the range of hearing and listens for the echoes. Different tissues reflect differently, and the machine converts the timing and strength of those echoes into a live image. Because it is real-time it shows movement — a beating heart, a moving fetus, blood flowing through a vessel — which no still image can.
What it is good and poor at
Sound travels well through fluid and soft tissue and badly through bone and air. So ultrasound excels at the liver, gallbladder, kidneys, bladder, uterus, ovaries, and superficial lumps, and it is the basis of an . It is largely defeated by the lungs and by bowel gas, and it cannot see through bone into the adult brain — which is where a or takes over.
Ultrasound is also used to guide procedures in real time — placing a needle for a or draining a collection — where seeing the needle enter the target is what makes the procedure both accurate and safe.
Where this comes up
Infectious Diseases
Dengue Fever
Most dengue is survived at home. The danger opens on days three to seven, usually as the fever falls. These are the warning signs that mean hospital now.
28 Aug 202614 min read
Neurology
Stroke: The Warning Signs and Why Every Minute Counts
Face drooping, arm weakness, speech trouble — any one of them, appearing suddenly, is a stroke until proven otherwise. Call 1122 and note the time.
28 Aug 202611 min read
Cardiology
Chest Pain: When to Worry and When to Call for Help
Chest pain lasting more than a few minutes with sweating, breathlessness or pain spreading to the arm or jaw is an emergency. Call Rescue 1122 now.
25 Aug 202611 min read
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Related terms
- X-rayRadiograph, Plain filmAn X-ray uses a small dose of radiation to produce an image, and it is best at showing bone and the chest. It is quick, widely available and usually the first imaging test requested.
- CT scanComputed tomography, CAT scanA CT scan uses X-rays taken from many angles and reassembled by computer into cross-sectional images of the body. It is fast and detailed, which makes it the scan of choice in emergencies, and it delivers a meaningfully higher radiation dose than a plain X-ray.
- MRIMagnetic resonance imagingAn MRI scan uses a strong magnetic field and radio waves to build detailed images of soft tissue. It involves no X-rays and no radiation.
- BiopsyTissue sampling, Histopathology sampleA biopsy is the removal of a small piece of tissue so that it can be examined under a microscope. It is the test that settles what a lump, an ulcer or an abnormal patch actually is, when scans and blood tests can only suggest.
- ThyroidThyroid glandThe thyroid is a butterfly-shaped gland in the neck that sets the body's metabolic pace. Too little hormone slows nearly everything down; too much speeds it up.
- EchocardiogramEcho, Cardiac ultrasoundAn echocardiogram is an ultrasound scan of the heart that shows the chambers and valves moving in real time and measures how strongly the heart pumps. It uses sound waves only, with no radiation and no injection in the standard test.
- RenalKidney, NephricRenal simply means relating to the kidneys. It appears throughout medical language — renal function, renal failure, renal stones — where the everyday word would be kidney.