Ultrasound uses high-frequency sound waves to produce images of inside organs. Prior to the examination, a special lubricating jelly, which helps transmit sound wave, is applied on the skin surface. When the transducer sends high-frequency sound waves through the body, the waves echo as an internal structure is reached and these echoes are subsequently reflected back to form images. Depending on the area being examined, the differences in echo time and intensity give rise to a unique image.
The ultrasound image is white or grey depending on the intensity of the reflection. Unlike other imaging modalities, ultrasound does not detect tissue density but rather the reflection of sound. Water, such as in cystic lesions, hardly reflects echoes and thus appear black on an ultrasound image. Conversely, highly dense tissues, such as bone or stones, readily reflect echoes and thus appear bright white on an ultrasound.
Moreover, as ultrasound produces real-time images, it can be used to examine blood flow. Coupled with the advantage of being radiation-free, it is widely used in pregnancy women for assessing fetal heart rate or detecting the location of placenta.
However, as Ultrasound does not travel well through air or bone, it might not be effective at imaging bony structures or hollow organs, such as the stomach and intestines. Should there be any concerns, patients may seek advice from doctors for the most effective imaging option.
Below is the information regarding the uses, safety issues, concerns of undergoing an Ultrasound examination and its advantages and limitations in comparison with other types of imaging modalities.
Ultrasound is by far the safest diagnostic examination without any known risks. Rarely do patients experience mild discomfort when the transducer is applied. Should you experience it, please inform our healthcare professionals immediately.
Food and water intake is not allowed for at least 6 hours for some examinations whereas sufficient amount of water is needed for examination of uterus and ovaries to allow a full urinary bladder for visualization.
Patients might be asked to change into a gown before the procedure and are reminded to remove all unnecessary objects such as jewelry (earrings, rings, body piercings), personal valuables, electron devices.
Should there be any issues, radiographers are there to provide as much assistance as possible.
Common tests for diagnosing cancer includes blood test, urine test, imaging test, biopsy and genetic test. Apart from diagnosing cancer, these investigations can also localise the primary site, differentiate the specific cancer cell type, perform cancer staging, identify whether there is metastasis, formulate treatment plan, monitor disease progression and detect recurrence. Below is the information regarding different tests.
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