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"Why would someone need an MRI and ultrasound?"


My mom has gout, and she has been recommended for an MRI, even though she just got an ultrasound. Is this excessive testing, or is there something the doctors can learn from an MRI that they can't from the ultrasound?


This is an understandable concern. The ultrasound and MRI techniques are chosen in specific situations when different aspects of the body tissue need to be visualized in different detail. An ultrasound is used first whenever it is possible that it will be sufficient to gain enough information about the problem.

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This is because an ultrasound machine uses no radiation when getting its images. In terms of cost, ultrasound is one of the cheaper imaging techniques. Therefore it is the first line technique when obtaining images of soft tissue that is close enough to the skin that the abnormalities can be seen among other things. It is also the reason whey we use it to look at babies that are still in the uterus (no radiation). An MRI also does not use radiation, but because it often takes up to an hour to obtain the needed images, it is much more expensive. Thus it is only utilized when it is the best method for looking at a structure. Often, an ultrasound will show an abnormality, but will not give enough information to tell what it is. In these cases, sometimes utilizing an MRI will give the additional information needed for a diagnosis and treatment plan. I hope that helps.

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