The primary difference between internal and external ultrasound lies in the method of probe placement: external ultrasound uses a probe placed on the abdominal skin, while internal ultrasound uses a probe inserted into the vagina.
Detailed Comparison of Internal and External Ultrasound
To understand the nuances, here's a detailed breakdown:
External Ultrasound
- Probe Placement: The ultrasound probe is placed on the surface of the abdomen.
- Procedure: A gel is applied to the skin to improve contact and transmission of sound waves. The technician or doctor moves the probe across the abdomen to visualize internal structures.
- Preparation: You'll need to remove or adjust clothing to expose the abdominal area. A full bladder may be required, depending on the type of scan being performed.
- Advantages:
- Non-invasive.
- Can visualize a larger area.
- Disadvantages:
- Image quality can be affected by body fat, gas, and the depth of the structures being examined.
- May require a full bladder, which can be uncomfortable.
Internal Ultrasound (Transvaginal Ultrasound)
- Probe Placement: A specially designed probe is gently inserted into the vagina.
- Procedure: The probe is positioned close to the organs being examined (e.g., uterus, ovaries).
- Preparation: You will need to undress from the waist down and lie on an examination table. A pillow may be placed under your hips for comfort. The probe is covered with a sterile sheath and lubricated for easy insertion.
- Advantages:
- Provides clearer and more detailed images of the pelvic organs.
- No need for a full bladder (in fact, you are usually asked to empty your bladder before the procedure).
- Disadvantages:
- Invasive.
- May cause mild discomfort.
Summary Table
| Feature | External Ultrasound | Internal Ultrasound (Transvaginal) |
|---|---|---|
| Probe Placement | Abdominal surface | Inside the vagina |
| Invasiveness | Non-invasive | Invasive |
| Image Clarity | Can be affected by various factors | Generally clearer and more detailed |
| Bladder Requirement | May require a full bladder | Requires an empty bladder |
| Discomfort | Generally minimal | Mild discomfort may be experienced |
| Area Visualized | Larger area | Focused on pelvic organs |
In conclusion, the choice between internal and external ultrasound depends on the specific clinical indication and the structures needing to be visualized. Internal ultrasounds generally provide better image quality for pelvic organs, while external ultrasounds are non-invasive and can visualize a larger area.
