Frequently Asked Questions (FAQs)

Topics:
  • Open MRI
  • Multi-Slice CT Scan
  • Ultrasound

Open MRI

What is an MRI?
MRI stands for Magnetic Resonance Imaging. It enables your doctor to obtain detailed images of the inside of your body without radiation. Instead, a large magnet and radio waves are used to create the images. An MRA is a special scan that lets your doctor view blood vessels in 3D. The pictures are obtained using the same principles as MRI.

How do I prepare for my exam?
No special preparation is required for MRI; however, it helps to wear comfortable, loose-fitting clothing with no snaps or zippers. You may also be asked to remove jewelry and hairpins.

What will I experience, and how long will my exam take?
Most scans are done with the patient lying flat and are completely painless. The body part to be scanned is placed in the center of the magnet, and nothing moves during the exam. It is very important to lie still during the examination. Most MRIs take from 20-45 minutes, although certain types of scans or multiple studies can take longer.

What if I'm claustrophobic?
South Valley Imaging has one of the first High-Resolution, Open MRI scanners in the Bay Area. This means we can easily scan most claustrophobic and large patients without sacrificing image quality. For patients who are very claustrophobic and need extra help, your doctor may be able to prescribe a sedative to take, but someone will need to drive you home after the test.

What is "contrast" or "dye," and how will it affect me?
MRI "contrast" or "dye" is a clear, water-based fluid that contains an element called gadolinium. MRI dye has been shown to be very safe with extremely rare cases of allergic reaction. It is not used on all exams, however your doctor or the radiologist may recommend it for certain studies. After taking an initial set of pictures, the dye is injected into the bloodstream, followed by an additional set of "comparison" images. The dye contains no iodine or radioactive elements, and is flushed out of your system within a few hours.

When and from whom will I get the results?
Our board-certified radiologists will interpret the exam and generate a report. This will be faxed to your doctor's office within 24 hours, and in most cases the same day. Your referring physician will review the report and follow up with you to discuss the results.

Is there anything that would prevent me from having an MRI?
Although MRI does not use ionizing radiation, patients who are or may be pregnant should check with their doctor before having an MRI performed. Also, patients who have any of the following items may not be able to have an MRI:

• Cardiac pacemaker
• Implanted defibrillator
• Brain aneurysm clips
• History of metal in the eyes
• Implanted devices, such as insulin pumps
• Certain types of ear implants

I have more questions - who should I ask?
South Valley Imaging's staff, board-certified MRI technologists and radiologists are readily available to answer questions and provide additional information.

Multi-Slice CT Scan

How long will my exam take?
This depends on the part of the body being examined and if injectable contrast is being used. In general, exams take from 30 minutes to 1 hour.

How do I prepare for a CT exam?
Review the paperwork your Doctor has given you. If your Doctor has ordered an exam with Contrast, you will be asked to stop eating 4 to 6 hours prior to your exam. You may have small sips of water if you need to take medications prior to your exam. When you make your appointment with us, the front office will advise you of any additional instructions

Why can't I eat or drink 6 hours before my CT?
This is only if your CT requires IV contrast. The contrast may cause nausea when there is food in your stomach. We want to prevent vomiting.

What is injectable contrast?
Sometimes your Doctor will order a CT scan "with contrast". This means a trained CT Technologist will insert a thin, plastic IV catheter into a vein, usually in your arm. The contrast will flow through this catheter into your arteries and veins to highlight them and give the Radiologist a more detailed study. Most patients feel some degree of warmth and get a salty taste in their mouth as the contrast is flowing through their blood vessels. These sensations last for just a few minutes

Are there any special instructions I need to follow after having a CT exam with contrast?
Yes. The contrast takes 24 to 48 hours to completely filter out of your body. We advise patients to drink lots of water to help this process. If you are a Diabetic taking Glucophage or Metformin, you may take your medication before your exam as usual. However, you must stop taking your medication for 48 hours after your CT scan.

What if I have had an allergic reaction to injectable contrast during a prior exam?
In this case, please inform your referring Doctor. You must be pre-medicated to help prevent having another reaction. The pre-medication regimen starts the day before your exam, so it is important to speak to your Doctor in a timely manner. You must also be pre-medicated if you have allergies to shellfish or iodine.

When will my Doctor get the results of my exam?
Your Doctor will get a faxed report within 24 hours of your exam.

If you have any further questions, please do not hesitate to ask the CT technologist performing your exam.

Ultrasound

What is an ultrasound? How does it work?
Ultrasound is a procedure that uses high-frequency sound waves produced by a small hand held device called a transducer to view internal organs and produce images of the body. Ultrasonic waves are inaudible and cause no sensation. The sound waves produced by the transducer cannot penetrate air, so gel is applied to help eliminate air pockets between the transducer and the skin. The technologist who performs the exam presses the transducer firmly against the skin and sweeps it back and forth to image the area of interest.

Some of the sound waves that pass through the body bounce back and are captured by the transducer. These “echoes” are then processed by a computer which generates an image.

Ultrasound technology was originally developed as sonar to track submarines during WWI. It has been used medically since the 1950s.

How long will my test take?
The length of time varies with the type of exam. Exams typically vary from 30 to 90 minutes. At the time you make your appointment, our staff will be able to give you an estimate on the amount of time to allow for the procedure as well as the appropriate preparation necessary for your particular exam.

How do I prepare for my ultrasound exam?
Upon scheduling your appointment, our staff will give you instructions on how to prepare for your specific exam. In certain cases, no preparation is necessary. However, if you are given preparation instructions it is important for you to follow them in order to ensure the best quality scan and the most accurate results. Please also inform our staff if you had any previous examinations of the same body part so our physician can use them for comparison.

When will I get my results?
Your ultrasound images will be analyzed by a radiologist, a physician who specializes in the interpretation of diagnostic imaging studies. The radiologist will produce a report of the findings based on these images. A signed report will be faxed to your referring doctor’s office by the end of the day. You may obtain your results by contacting your doctor who referred you for the exam.

Do you do other ultrasounds other than the pregnancy ones?
What are some of the common uses of ultrasound?
Ultrasound imaging is used extensively for evaluating the abdominal organs (kidneys, liver, gallbladder, pancreas, and spleen), the non-gravid uterus, breast, thyroid, testicles as well as studies of the major blood vessels.

Why do I have to fast for an abdominal ultrasound?
Ultrasound waves do not pass through air. Eating or drinking contracts the gallbladder, making it difficult to visualize, and also produces intestinal gas which prevents or significantly limits the visualization of abdominal structures. While some abdominal gas is always present, fasting before the exam ensures for the best scan possible.

Why do I have to have a full bladder for a pelvic ultrasound?
Two methods are used for performing a pelvis ultrasound, trans-abdominally (the probe is placed on top of the abdomen) and endovaginally (a special probe is placed inside the vagina). A full bladder is usually necessary when the scan is done transabdominally. A full bladder displaces bowel and acts as a window for the ultrasound waves to pass through to visualize the pelvic organs. Ultrasound doesn't go through air (gas in the bowel) but transmits well through liquid (as in the case of the urine in the bladder). In an endovaginal scan, however, a full bladder will not be necessary.

I had a scan early in the pregnancy and then one later on;
which due date is correct?
The results of the scan performed early in pregnancy for 'dating' purposes will be more accurate. In the later part of pregnancy the measurements will be affected by growth variations and will no longer reflect the fetal 'age' correctly.

How safe is it to have multiple OB ultrasound scans?
There is presently no evidence of a cumulative effect of ultrasound in the fetus. For standard diagnostic ultrasound, there are no known harmful effects on humans.

When can I find out the gender of my baby?
How accurate is the diagnosis of fetal gender by ultrasound?
Most of the time one should be able to tell the sex of the baby by about 20 weeks and sometimes even as early as sixteen weeks. On the other hand, visualization of any fetal part depends of a host of factors such as fetal position and amount of amniotic fluid. There have been occasions when gender cannot be determined even at 28 weeks.

Accuracy is usually somewhere between 95 and 100 percent, particularly after about 20 weeks. However, the technologist may not always get a good view of the fetus for a variety of reasons, and therefore the actual sex of your baby might differ from the apparent sex of your baby on the images obtained.