Not for emergencies. Call 911 or go to the nearest ER for any urgent or life-threatening symptom. DOD is not an emergency service.
Diagnostic Ultrasound Education Guide
Diagnostic ultrasound is a medical imaging technology that uses high-frequency sound waves to create real-time images of internal body structures. It does not use ionizing radiation and is widely used for abdominal, pelvic, vascular, musculoskeletal, and thyroid evaluation.
Educational content only. This page does not constitute medical advice. Clinical appropriateness is determined by a licensed provider. DOD does not perform or interpret ultrasound studies.
Quick Answer
Diagnostic ultrasound uses high-frequency sound waves emitted by a transducer (probe) placed against the skin. The sound waves bounce off internal structures and return to the transducer, which converts them into real-time images. No ionizing radiation is involved. Ultrasound is commonly used for evaluation of abdominal organs, pelvic structures, blood flow (Doppler), musculoskeletal soft tissues, and the thyroid. A provider order is required at most facilities. DOD can review ultrasound order requests for eligible patients in supported states.
How Ultrasound Works
A handheld device called a transducer or probe is placed on the skin surface over the area of interest, typically with ultrasound gel applied to improve sound wave transmission. The transducer emits brief pulses of high-frequency sound waves (typically 2–18 MHz for diagnostic imaging). When the sound waves encounter tissue boundaries with different acoustic properties, they reflect back to the transducer. The time it takes for the echo to return, combined with the strength of the reflected signal, allows a computer to calculate the depth and density of the structure and construct a real-time image.
Ultrasound imaging is operator-dependent — the quality of the images and the information derived depends significantly on the skill and technique of the sonographer performing the exam. According to RadiologyInfo.org, ultrasound is real-time, portable, widely available, and generally lower cost than MRI or CT.
Key limitations include reduced ability to image through bone or gas-filled structures (bowel, lungs), which limits ultrasound's usefulness for certain body regions. Patient body habitus can also affect image quality.
Types of Ultrasound and What They May Evaluate
Abdominal Ultrasound
Liver, gallbladder, spleen, kidneys, pancreas (limited), aorta, and surrounding structures
Pelvic Ultrasound
Uterus, ovaries, bladder; prostate evaluation via transrectal approach
Thyroid Ultrasound
Thyroid gland size, nodule characterization, vascularity
Vascular / Doppler
Blood flow in veins and arteries — venous DVT evaluation, arterial assessment, portal vein
Renal Ultrasound
Kidney size, morphology, obstruction (hydronephrosis), bladder post-void residual
Musculoskeletal
Tendons, muscles, soft tissue masses, joint effusions — rotator cuff, Achilles, plantar fascia
Breast Ultrasound
Characterization of mammographic findings, evaluation of dense breast tissue, cyst vs solid differentiation
Scrotal Ultrasound
Testicular size, vascularity, masses, hydrocele, varicocele
Educational only. Clinical appropriateness is determined by a licensed provider.
Provider Order Requirement
Most outpatient ultrasound facilities require a valid provider order before scheduling. DOD can review ultrasound order requests for eligible patients in supported states when medically appropriate.
Frequently Asked Questions — Ultrasound
Sources and Further Reading
- Ultrasound — Patient Information — RadiologyInfo.org (ACR / RSNA)
- Ultrasound — MedlinePlus (U.S. National Library of Medicine / NIH)
- Ultrasound Safety — U.S. Food and Drug Administration (FDA)
Related Education and Order Pages
Need a Provider Review Before Scheduling Ultrasound?
$40 virtual provider review. Orders issued only when medically appropriate. Facility acceptance varies.
Start Virtual Consult — $40Not for emergencies. Orders not guaranteed.
Educational content only. DOD is not an imaging center, laboratory, radiology facility, or emergency service. DOD does not perform or interpret ultrasound studies.