Mountain Medical

Ultrasound, MRI and CT Scan Exam Facts

Ultrasound Questions
MRI Questions
CT Questions

What is Ultrasound and how does it work?

Ultrasound imaging, also called sonography, is a method of "seeing" inside the body through the use of high-frequency sound waves. Ultrasound imaging is based on the same principles involved in the sonar used by bats and ships. As the sound passes through the body, echoes are produced that can be used to identify how far away, how large and how uniform an object is. There is no radiation associated with an ultrasound exam.


When are Ultrasounds performed?

Ultrasound is a useful way of examining many of the body's internal organs, including the heart, liver, gallbladder, spleen, pancreas, kidneys as well as pelvic anatomy including the bladder, uterus, and ovaries. Because ultrasound images are captured in real-time, they can show movement of internal tissues and organs and blood flow.


How should I prepare for the procedure?

You should wear comfortable, loose-fitting clothing for your ultrasound exam. Other preparation depends on the type of examination you will have. For some scans, you may be instructed not to eat or drink for as many as 12 hours before your appointment. For others, you may be asked to drink lots of water prior to your exam and avoid ing, so that your bladder is full when the scan begins. This helps with visualization of the uterus, ovaries and bladder. For specific details about your exam preparation, click Exam Preparation.


What will I expect during my ultrasound?

During an ultrasound exam, you are usually lying on an examination table. Warm gel is applied to the body in the area to be examined, to help the transducer make secure contact with the skin. The technologist presses the transducer firmly against the skin and sweeps it back and forth to image the area of interest. Ultrasound imaging is usually painless, fast, and easy.

For women undergoing a pelvic ultrasound exam, in addition to "trans-abdominal" imaging, where gel is placed on the lower abdomen, a "trans- l" scan may need to be performed. In this instance, a transducer is placed within the in order to provide more detailed images of the uterus and ovaries. When the examination is complete, the patient will be asked to wait while the images are reviewed.


When will I get the results?

The exam will be reviewed by a board certified radiologist shortly after the completion of your exam. The radiologist will dictate a report that will be sent to your referring or primary physician within 24 hours of the procedure.




What is an MRI and how does it work?

MRI stands for Magnetic Resonance Imaging. Unlike other radiology procedures that use x-ray radiation, MRI uses magnetism, radio waves, and a computer to help produce the images of the body. The MRI scanner is able to produce images in any direction with precise detail.

The patient lies on a table and the large magnetic field surrounds the table. The magnetic field causes the hydrogen protons in the body to align themselves with this magnetic field. A radio frequency is then transmitted through the body causing the hydrogen protons to move. When the radio frequency is turned off, the protons stop moving. As this happens, the protons give off a slight signal, which in turn is measured by the computer and transformed into images. Thousands of these signals are measured and processed during a single scan series.


When are MRI scans performed?

MRI scans are used to diagnose diseases in many areas of the body. In the head, MRI is used to look for tumors, strokes, aneurysms, and nervous system diseases such as Multiple Sclerosis. MRI is considered to be the best exam to look at the spine, extremities and joints.


How do I prepare for an MRI scan?

Most MRI exams do not require any fasting before the procedure. Abdomen exams require the patient fast for several hours before the test. When you are scheduled for an MRI, it is important to know whether you have any metal objects implanted in the body. The MRI staff will ask you about things such as aneurysm clips and pacemakers.


Are there any risks involved?

MRI is a painless radiology procedure that has the advantage of not using any x-ray radiation. There are no known side effects of the scan.

However, since the MRI scanner is a large magnet, it is very important to notify the technologist of metal implants and it is necessary to remove all metal objects such as keys, watches and jewelry before entering the scan room. In some cases, the exam cannot be performed due to certain implants. These include:

  • Cardiac pacemaker
  • Implanted defibrillator
  • Brain aneurysm clips
  • Metal in the eyes
  • Implanted devices, such as insulin pumps
  • Certain types of ear implants
  • The technologist will give you a more complete list and can answer any questions you may have before the scan.

The MRI exam may require an injection of a contrast material called gadolinium. This "highlights" certain areas that may be hard to see without contrast. The complication rate for this contrast is very low.


What will I experience during a scan and how long does the scan take?

You will be asked to lie on a table. The table will slowly move to the center of the magnetic field. The scanner is a long tube open at both ends. The part of the body being scanned must be in the middle of this tube.

The procedure usually lasts 15 - 30 minutes and you must lie very still. Every consideration will be taken to make you comfortable during the procedure and you can listen to your favorite radio station or CD. Some patients find that they can be somewhat claustrophobic during this scan. A light sedative can be given to minimize this sensation.


When will I get the results?

The exam will be reviewed by a board certified Mountain Medical radiologist shortly after the completion of your exam. The radiologist will dictate a report that will be sent to your referring or primary physician within 24 hours of the procedure.



What is a CT scan and how does it work?

CT or CAT is short for Computerized (Axial) Tomography. This is an x-ray procedure that combines multiple x-ray images and generates cross-sectional views or picture slices of your internal organs. By examining each slice and/or combining the slices into three dimensional (3D) images, the radiologist can diagnose normal or abnormal structures within the body and help your doctor diagnose or follow any disease process.

The donut-shaped machine has a table that slides the patient in and out of the scanner while taking continuous x-rays. The information gathered is sent to a computer. The computer is able to take all of this information and transform it into many images that come up on the screen.


Why are CT scans performed?

CT scans are performed for various reasons depending on the area of the body being scanned. Most often, CT scans are used to look at:

  • Traumatic Injuries to the head such as blood clots or skull fractures
  • Brain tumors, infections or bleeding into the brain
  • Spinal imaging to look at the bony structures of the vertebrae, as well as the anatomy of the intervertebral disc spaces and the spinal cord
  • Chest or abdominal tumors, cysts, or infections
  • Complicated bone fractures
  • Blood vessel disease or injury

CT has become the screening test of choice for kidney stones, diverticulitis, and appendicitis. CT of the pulmonary arteries has become an important tool to diagnose life-threatening blood clots or emboli to the lungs.

We provide screening tests for coronary heart disease, lung cancer, and colon cancer.


How do I prepare for a CT scan?

At the time your scan is scheduled, our staff will tell you or your doctor's office how you need to prepare for the exam. The procedures are grouped into two categories: without contrast or with contrast. The use of contrast material, or "dye," can help to define anatomy and "highlight" abnormal structures in the body.


What is contrast?

There are two kinds of contrast commonly used for CT scans: oral and IV. The oral contrast is given by mouth. This contrast is used for certain abdominal scans and is given 1½ - 2 hours prior to the procedure. This contrast is used to highlight your stomach and intestinal track. The IV contrast is given by placing an IV in your arm and injecting the contrast into the veins. This contrast contains iodine. Because some people are allergic to iodine, we will ask you some pertinent questions in advance. IV contrast is most often used to look for tumor, infection, or to look at the blood vessels.

Regardless of whether or not a contrast is used, it is usually recommended that you not eat or drink anything, except the oral contrast if given, for several hours before your CT scan. You may take prescribed medication with small sips of water. For specific details about your exam preparation, click Exam Preparation.


Are there any risks involved?

The overall risks of CT are minimal. One risk of a CT scan is radiation, the same risk that is involved with any x-ray test. Mountain Medical physicians and staff make sure that the least amount of radiation is used to provide the best images needed to make an accurate diagnosis.

If an intravenous (IV) contrast is used, a small number of patients may experience a minor reaction. Some of these reactions are due to allergy, some are not. The IV contrast often makes you feel hot for a short period of time and may give you a funny taste in your mouth for a short time. These are normal reactions and are not allergy. Patients who are allergic to the iodine in the contrast usually have only a minor reaction; major allergic reactions are rare.


What will I experience during the scan?

The CT scanner is very fast. The procedure is painless and will take 5-15 minutes. If IV contrast is going to be used, a small needle will be placed in your arm. You will be asked to lie on the comfortable, padded table on your back or stomach. You may be asked to drink additional oral contrast just prior to lying down. The table will move back and forth and you will be asked to hold your breath so that the pictures are motion free.


When will I get the results?

The exam will be reviewed by a board certified radiologist shortly after the completion of your exam. The radiologist will dictate a report that will be sent to your referring or primary physician within 24 hours of the procedure.