An ultrasound is performed using a handheld device called a transducer, which is connected to a computer and sends high-frequency sound waves into the body. The returning echoes create an image on the screen. Here's a breakdown of the process:
Ultrasound Procedure: A Step-by-Step Guide
-
Preparation: The patient usually lies down on an examination table. The area of the body being examined is exposed, and a clear, water-based gel is applied to the skin. This gel helps the transducer make good contact with the body and eliminates air pockets that can interfere with the sound waves.
-
Transducer Placement: The healthcare professional (sonographer or doctor) holds the transducer against the skin and moves it around the area of interest. Different types of transducers exist, each optimized for specific imaging depths and applications.
-
Sound Wave Emission: The transducer emits high-frequency sound waves into the body. These sound waves are inaudible to the human ear.
-
Echo Reception: As the sound waves travel through the body, they encounter different tissues and structures. Some of the sound waves are reflected back to the transducer as echoes. The density and characteristics of the tissues determine the strength and timing of these echoes.
-
Image Processing: The transducer receives the returning echoes and sends this information to the computer. The computer processes the data, converting the echoes into electrical impulses that are then translated into a visual image displayed on a monitor.
-
Image Interpretation: The healthcare professional interprets the images to identify normal and abnormal structures. They may take still images or record short video clips for further review.
-
Post-Procedure: Once the examination is complete, the gel is wiped off the skin. The patient can usually resume their normal activities immediately, unless specific instructions were given.
Factors Affecting Ultrasound Image Quality
Several factors can influence the quality of the ultrasound images:
- Body Size and Shape: Excess body fat can sometimes reduce the penetration of sound waves and make it harder to obtain clear images.
- Air or Gas: Air or gas in the bowel can block sound waves and obscure underlying structures.
- Patient Movement: Excessive movement can blur the images.
- Scar Tissue: Scar tissue can also interfere with sound wave transmission.
Types of Ultrasound Techniques
While the basic principle remains the same, various ultrasound techniques are available:
- Doppler Ultrasound: Measures the speed and direction of blood flow.
- 3D Ultrasound: Creates three-dimensional images.
- 4D Ultrasound: Shows three-dimensional images in real-time.
- Echocardiogram: Ultrasound of the heart.
- Endoscopic Ultrasound: Combines ultrasound with endoscopy for a more detailed view of internal organs.
