Hoag is proud to announce that it is the first hospital on the West Coast to routinely offer patients a revolutionary hybrid technology that will forever change the way neurology, cancer and cardiac patients are diagnosed and treated.

Positron emission tomography/magnetic resonance imaging (MR/PET), is an innovative imaging technology that will help in early and accurate diagnosis of various cancers, degenerative neurological disorders such as Alzheimer’s disease, mild traumatic brain injury and heart disease. MR/PET will also help physicians tailor treatment options to ensure patients receive the care that will most likely work best for them.

MR/PET is a hybrid imaging technology that combines in one instrument the superior MR imaging of structure, and imaging of tissue metabolism on a molecular level offered by PET. By creating simultaneous PET and MRI data, the new technology provides more detailed information than either technique can alone, in one step. This eliminates the need for multiple tests.

The structural and molecular information from a MR/PET will help cardiologists and surgeons quickly and efficiently determine who could best benefit from surgery following a heart attack. The applications for neurology include more definitively diagnosing a traumatic brain injury or Alzheimer’s disease through identifying the presence of certain molecular deposits in the brain and how the brain is utilizing energy.

In cancer, MR/PET's ability to see specific molecules in the body will allow us to target disease in a much more patient-specific, individualized manner, leading to better and more efficient cancer treatment. Oncologists will favor this new technology for patients who now have to undergo a battery of tests, including PET and CT scans, both of which use ionized radiation.

What to Expect

Resting Phase

The entire MR/PET procedure typically lasts 2-3 hours. It begins with an injection of a tiny amount of radioactive glucose (sugar) “tracer” solution that enables evaluation of glucose metabolism (function) in the body. There are no known side effects to this injection. Once injected, you will be asked to rest in a quiet room and avoid significant movement or talking, which may alter the localization of the tracer. The resting period lasts approximately 60 min.

Imaging Phase

The MR/PET scanner is very similar in size to an MR scanner. Magnetic Resonance Imaging (MRI) produces images of the body’s internal structures by passing radio waves through a powerful magnetic field. Differing frequencies of radio waves are produced by the different body structures, in return, these are mapped and converted into digital images by a computer. MRI is especially good for imaging soft tissues in the body, including the brain, nerves, muscles and organs.

You will be lying on your back on a movable table that slides into the center of the machine. The technologist may use straps or bolsters to help you stay still and maintain proper positioning during the examination. He or she may place a device called a coil around the part of the body being studied. This device sends and receives the radio waves which are used to generate the image.

The imaging phase will take approximately 60 minutes in the scanner. In some cases, more than one scan is required; you will be notified of the number of scans at the time of injection. Your total time commitment will be approximately 2 hours and reports should be in your doctor's office within 48 hours.

The MR/PET scanner is noisy. You will be given a set of earplugs or headphones to wear during the examination to reduce the noise. It is important that you follow the technologist's instructions. You will be asked to remain still multiple times throughout the examination while each sequence is being performed. If you are claustrophobic (have a fear of being closed-in), you may want to discuss the option of receiving sedation for the study with your physician prior to your appointment. Some studies require the administration of contrast material into the vein. MRI contrast is called gadolinium and is different than the contrast administered for CT scans. A radiology technologist or nurse will place an intravenous line through which he or she will give the contrast.

How to Prepare

When you schedule your appointment, we will inform you about any specific preparations depending upon the specific procedure your doctor has ordered. Please contact the Scheduling Department at 949-764-5573 if you have any questions.

If you have a pacemaker (unless it is a MRI safe pacemaker), or breast tissue expanders, please contact your physician as you are unable to have an MR/PET procedure.

Options exist for patients who suffer from claustrophobia or who are unable to lie still for several minutes at a time. Because no radiation is involved, a family member or friend can remain in the scan room with you to offer comfort and support. Anyone who enters the scan room will need to be screened by our staff.

A second option is taking anxiety-relieving medication such as Valium, which your physician can prescribe for you. If you are planning on taking anti-anxiety medication for this procedure, do not take your medication until you sign your consent when you arrive. If you are already medicated, your consent will not be valid and your procedure may need to be rescheduled. You can take your medication during the 60 minute resting stage before entering the scanner. Also, be aware that you cannot drive for several hours after you take this medication, so you will need to arrange for transportation home. If you have a programmable shunt, you will need to go to your physician’s office immediately after the MRI to have it re-programmed. Please schedule this in advance with your physician’s office.

If you have a Vegus Nerve Stimulator, you can only have a MRI of the brain and it must only be done at Hoag Hospital Newport or Hoag Hospital Irvine.

If your physician has ordered your procedure with radiographic contrast:

  • You should inform your physician if you have any allergies. If you have been told you are allergic to contrast or have ever had a reaction to Iodine or any form of contrast media, your doctor may prescribe medications to reduce the risk of an allergic reaction. A Radiology nurse should contact you. If you have not been contacted by a Radiology nurse at least 24 hours prior to your appointment, please contact the Imaging Scheduler immediately.
  • If you have diabetes, kidney problems, lupus, surgery on your kidneys or multiple myeloma, you must have lab work that includes a BUN and Creatinine performed within 30 days of your exam. If you are over the age of 65 you must have lab work within 90 days of your exam. This provides us with information regarding your current kidney function. Please call your physician if you have not had this blood work.
  • If you have been diagnosed with diabetes and/or you are currently taking any of the following medications: Metformin, Gluicophage, Glucophage XR, Fortamet, Riomet, Metaglip, Glucovance, Actoplus Met, Avandament or Junamet, stop taking your medication for a total of 48 hours after your exam. You must contact your physician for alternative medications and instructions prior to your exam.
  • If you are currently receiving Dialysis; please schedule your dialysis to follow your procedure with Contrast or the following day. It is imperative you have dialysis no later than the following day after you have received contrast for your procedure.

Instructions for the 24 hours prior to your exam time

We encourage you to hydrate with oral fluids at least 24 hours prior to your study.

Do NOT engage in any strenuous exercise for 24 hours prior to your exam

You may receive additional specific instructions when you schedule your appointment depending upon the type of procedure that will be performed. Some types of scans require fasting beforehand.

Please complete, print out and bring with you the following forms to your appointment:

Instructions for the 12 hours prior to your exam time

Stay on a low carbohydrate diet.

Day of the Exam

Do NOT eat anything six (6) hours prior to your appointment time. This includes mints and chewing gum. Please drink several glasses of water (2-6) and take medications. If you need to eat, please limit yourself to a small protein-only meal. If you are diabetic, please consult your doctor for questions regarding medication.

You will need to complete a detailed screening sheet, on which you will be asked whether or not you have any metal or other devices implanted in your body that may interfere with the scan or cause injury to you. If you have any concerns or questions about what expect of the procedure, please ask the technologist before you enter the room. We also are happy to answer your questions by telephone at any time before your appointment.

Because the MR/PET unit uses a very large, strong magnet, you will be asked to remove and store jewelry, keys, wire-frame eyeglasses and any loose metal objects. You may be asked to change into a gown unless you are wearing clothing that is metal-free. Please wear comfortable clothing with no metals, buttons or zippers. Preferably wear a sweat outfit or active wear.

You will receive an injection.

You will be asked to sit quietly in the waiting room for 60-90 minutes after the injection.

If you have hair extensions with metal clips, please remove them prior to the MR/PET procedure.

Side Effects

There are no residual side effects from a PET scan. On rare occasions, MR contrast may cause reaction. You will be able to drive yourself home unless you have taken any sedation medication. Consult your physician before the exam if you may possibly be pregnant or are breast-feeding.

Follow Up Care

There are no restrictions after the test, although you should drink plenty of fluids to flush the radioactive substance from your body.


Locations where Hoag provides MR/PET Imaging services