CT, Ultrasound, MRI- What’s the Difference?

Here at Preventative Diagnostic Center, we utilize a low-dose CT Scanner. We do not perform ultrasound or MRI exams, however we’re often asked about the difference between the procedures. Below is an overview of the key differences.

Differences between Computed tomography (CT) and Ultrasound (US) in screening exams:

1. CT has a far higher spatial resolution (that is the ability to see structures more clearly)
2. CT is not motion dependent (Ct can be done in a single breath hold)
3. CT is not operator dependent (US is extremely hard to reproduce the same results on different equipment with different users)
4. CT does require radiation while US does not
5. Larger segments of the body can be visualized in seconds.
6. US cannot be used to visualize the coronary arteries in a screening procedure

In summary CT has Higher spatial resolution, is reproducible and can cover larger segments of the body in seconds. It is not patient or operator dependent but does require a small dose of radiation.

Differences between Computed Tomography (CT) and MRI in screening exams

1. CT has higher spatial resolution as MRI is using quick scanning techniques to accomplish full body screening.
2. CT can display and use much thinner image data to produce its images. Due to the lack of detailed scanning typically used in MRI full body screening due to time constraints.
3. Heart scanning is not done in an MRI full body scan.
4. Images are much less clear with MRI due to a number of issues to include. Breathing, peristaltic and vascular motion as well as patient motion and tolerance of the equipment I.e., claustrophobia.
5. Positive findings are almost always sent to CT for conformation with the MRI exam.
6. CT can be accomplished in a matter of seconds while MRI at a minimum must be accomplished over a 15min period.
7. MRI requires no radiation and is done with magnets and pulsing radio frequency

In summary again CT has a much higher spatial resolution and is much more easily tolerated by the patient.  Any positive findings will be sent to CT for conformation and the heart will not typically be included in this exam. Accurate measurements of findings will require a CT due to the lack of resolution.