I find in today's world physicians among other designated health professionals are using more diagnostic imagery and laboratory service to diagnose cause of illness. Research and advanced technology contribute to increases for health costs and risk.
Each patient as an individual, have differing health care needs, usually a matter of record documented in their medical history. Updates should note all change in their health on a timely basis. Upon review health risk and cost may be recognized. The diagnostic report is usually returned to the qualified attending physician for conformation of further treatment if warranted. If you, as the patient, are not in agreement, then a second opinion may be the best option of choices.
Diagnostic means using ultra sound which utilizes "high frequency sound waves to view soft tissues such as muscles and organs." Doppler ultra sound allows "blood flow through a blood vessel to be visualized."
Before signing a consent form for a diagnostic procedure be sure your health insurance will cover all costs, which can be very costly. Otherwise you may be billed for costs.
In summary: Diagnostic Service used to diagnose cause of illness needs to be under supervision of a qualified physician or other designated health professionals. A patient is an individual and should be treated as such. If placed at risk, risk needs justifying.