The Differences Between Diagnostic Ultrasounds and CT Scans

Updated on December 9, 2022
The Differences Between Diagnostic Ultrasounds and CT Scans

Healthcare providers order diagnostic ultrasounds and CT scans to generate images of the body’s internal structures. Healthcare professionals use these images to diagnose and monitor diseases and conditions. Discover the differences between diagnostic ultrasounds and CT scans.

Use of Sound Waves vs. Radiation

One of the key things to know about ultrasound is that it doesn’t use radiation. In sonography, an ultrasound technician uses a probe that generates high-frequency sound waves.

When the sound waves reach boundaries in the body, like the boundary between tissue and bone, the waves echo back to the probe. The ultrasound machine records these echoed sound waves and generates an image.

While ultrasound uses sound waves, a computerized tomography (CT) scan uses small amounts of radiation to generate images. During the imaging procedure, the patient lies in the opening in the middle of the CT machine. The donut-shaped x-ray rotates around the patient, taking images from different angles around the patient’s body.

A computer creates cross-sectional images, or slices, based on the CT scans. Doctors can view the images individually or stack them together to create 3D images.

Imaging of Soft Tissues and Bony Structures

Another difference between diagnostic ultrasounds and CT scans is that doctors usually do not order ultrasound procedures to view bony structures. Instead, they use ultrasounds to view soft tissue, and advanced ultrasounds can create highly detailed images.

In contrast, CT scans create detailed images of bony structures. A CT scan can image bones, organs, and blood vessels during one procedure.

Time and Cost of Procedure

Ultrasounds generally take between 30 minutes and an hour to complete. The procedure costs between $100 and $1,000.

CT scans take between 10 and 30 minutes to complete. If the patient takes an oral contrast to help distinguish tissue from its surroundings, the CT scan procedure can take over an hour. A CT scan costs between $1,200 and $3,200.

Diagnostic ultrasounds and CT scans are non-invasive or minimally invasive. These imaging techniques quickly deliver accurate results that help physicians determine treatments to improve patient health and save lives.

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