A window that closes
In newborns, the bones of the skull have not yet fused, and the large fontanel serves as a natural acoustic window: through it, ultrasound freely passes to the brain. This allows you to safely and without anesthesia evaluate brain structures, the size of the ventricles, identify intraventricular hemorrhages, cysts, signs of hypoxic-ischemic damage and developmental defects. The Doppler mode complements the picture by assessing blood flow in the cerebral arteries. The fontanel closes by 12–18 months, after which research becomes impossible - therefore, neurosonography is performed in the first year of life, usually at 1 month and further as indicated, especially in premature infants and after complicated births.
Why ultrasound is the first line method
Ultrasound does not use ionizing radiation, is fast, inexpensive, and provides images in real time. Therefore, it begins with the diagnosis of most diseases of internal organs, thyroid and mammary glands, blood vessels, joints and soft tissues.
A separate advantage is the ability to evaluate not only structure, but also movement: blood flow in the vessels, heart contractions, peristalsis, and fetal movements. Neither CT nor MRI in standard mode show this.
Ultrasound modes
- B-mode - a conventional two-dimensional gray scale image of the organ structure
- Dopplerography - assessment of the speed and direction of blood flow in the vessels
- duplex scanning - a combination of vessel imaging and blood flow analysis
- 4D - volumetric image in real time
What influences the quality of research
Ultrasound does not pass through air and does not pass well through dense bone tissue. Therefore, gases in the intestines interfere with examination of the pancreas, and the lungs and brain of an adult are inaccessible for examination. This explains the preparation requirements: diet and fasting study significantly improve visualization.
The second important factor is the doctor: ultrasound diagnostics largely depends on the experience of the specialist, since the image is assessed at the time of the examination.