Question

What is the ratio of cost of a “typical” sonogram vs. MRI for the same region (head, chest, etc.)?

What is sonography— what kind of image does it create and how?

What are two reasons to use a sonography instead of a CT scan?

What are two reasons to use a sonography instead of an MRI? Please give two reasons.

Why are very high frequencies used?

What sort of radiation is involved? Is sonography “perfectly safe”? If not, what are the dangers?

Answer 1

The ratio of Sonography/MRI is on an average 1/10.

Sonography, also known as ultrasound technology, the analysis of sound using an instrument which produces a graphical representation of its component frequencies. High-frequency sound waves are transmitted from the probe through the gel into the body. The transducer collects the sounds that bounce back and a computer then uses those sound waves to create an image.

Radiation exposure from CT scan is high but in sonography radiation is none. Ability to change imaging plane without moving the patient.

Because MRI uses a very powerful magnet to obtain images, it can be unsafe for patients who have implanted ferromagnetic objects, such as certain medical devices or shrapnel. Ultrasound offers the benefit of producing images quickly and in real time, so movement can easily be observed on ultrasound. MRI images can provide greater detail, but these images are time consuming to capture are typically static.

Ultrasound can't detect objects that are smaller than its wavelength and therefore higher frequencies of ultrasound produce better resolution.

The advantages of ultrasonography far outweigh any risks associated with this technique. However, several studies have highlighted the harmful effects of ultrasound on pregnant mammals such as mice though this effect has not yet been shown in humans. Also, increased exposure to ultrasound waves leads to heating up of tissues, changes in pressure and other mechanical disturbances.