Which procedure is defined as invasive because it involves inserting instruments into the body?

• A. Ultrasound
• B. Catheterization
• C. X-ray
• D. EKG

Answer: (B)

Invasiveness means involving insertion of instruments into the body. Catheterization fits this because a catheter—a flexible tube—is inserted into a blood vessel or urinary tract to access internal areas for observation or treatment. That insertion requires sterile technique and carries risks like infection or bleeding, which is why it’s considered invasive.

The other options don’t involve inserting instruments into the body. Ultrasound uses sound waves sent from a transducer pressed on the skin. X-ray imaging is done from outside the body, sometimes with contrast, but it doesn’t require inserting a device inside. EKG records electrical activity with surface electrodes on the skin.