What kinds of MRI are there?
MRIs are used to scan and examine one part of your body at a time. The scan can focus on many parts of the anatomy. There is even a form of MRI that can look at blood vessels and the flow of the blood as it goes through them. This is called Magnetic Resonance Angiography (MRA). These kinds of scans can help to find arterial and vein problems, such as a blocked vessel, torn vessel lining or aneurysm.
The different kinds of MRI scans include, but are not limited to: Abdomen, Adrenal Glands, Ankle (Achilles), Bladder, Brain, Breast, Cervical Spine (C-Spine), Chest, Coccyx (Tailbone), Elbow, Face (Maxillofacial, Parotid Glands), Femur (Thigh, Upper Leg), Fingers, Foot, Forearm (Lower Arm), Hand, Hip, Humerus (Upper Arm), IAC's (Inner Ear), Kidneys (Renal, Knee, Liver, Lower Leg (Calf, Tibia, Fibula), Lumbar Spine (L-Spine), Mandible (Jaw), MRA Abdomen (Abdominal Aorta), MRA Brain, MRA Chest, MRA Kidneys, MRA Knee, MRA Neck, Nasopharynx (Tongue), Neck, Orbits (Ears), Pancreas, Pelvis, Pituitary Gland, Prostate Gland, Sacrum, Shoulder, SI Joints (Pelvic Joints), Thoracic Spine (T-Spine, Dorsal Spine), TMJ (Jaw Joints), Toe, Uterus, Wrist, etc., etc…
An MRI is the choice mode of diagnostic imaging by most doctors. It can help to find most malignancies and neurological diseases of the brain and spine, such as:
- Brain Tumors
- Alzheimer's Disease
- Cervical Cancer
- Multiple Sclerosis (MS)
Other common uses of the MRI scan are to examine:
- Organs of the chest and abdomen—including the heart, liver, kidneys, spleen, bowel, pancreas and adrenal glands.
- Pelvic organs including the reproductive organs in the male (prostate and testicles) and the female (uterus, cervix and ovaries).
- Enlargements or blockages of blood vessels, including the aorta, renal arteries, and arteries in the legs.
- Diseases of the liver, such as cirrhosis, and that of other abdominal organs, including the bile ducts, gallbladder, and pancreatic ducts.
- diseases of the small intestine, colon, and rectum
- Cysts and solid tumors in the kidneys and other parts of the urinary tract.
- Causes of pelvic pain in women, such as: fibroids, endometriosis, and adenomyosis
- Suspected uterine congenital abnormalities in women undergoing evaluation for infertility.
Some MRIs are done using contrast. Contrast, or Contrast Media, is X-Ray dye, or a compound thereof, used to provide a visual distinction between tissues, such as blood vessels and soft tissue, or between normal and abnormal tissues. The compound of the contrast is determined by the specific use. There are different kinds of contrast agents; these are the more common:
- Intravascular Contrast Agents – This kind stays in the blood longer and is used mostly to assess dead tissues around the heart, myocardial problems and tumors.
The most popular Intravascular Contrast Agents are Ultrasmallsuperparamagnetic iron oxide (USPIO), Gd Labeled Albumin, Chromium labeled red blood cells and Gd-DTPA labeled dextran
- Oral Contrast Agents – These are mostly used to enhance the intestines and bowel, the full gastrointestinal tract.
Types of oral contrast agents with positive signal enhancement are Paramagnetic Contrast Agents (e.g., Gd-DTPA solutions) and Short T1-relaxation gastrointestinal agents (e.g., mineral oil).
Categories of negative oral contrast agents are Gastrointestinal diamagnetic Contrast Agents, Gastrointestinal Superparamagnetic Contrast Agents and Perfluorochemicals
- Paramagnetic Contrast Agents – This is the most common when being using an intravenous contrast agent. It is mostly used for imaging of the heart, intervertebral collapse, fibrosis, plaques and detecting tumors. Common side effects of this one are nausea, vomiting, seizure, feeling warm & headaches.
Paramagnetic substances, for example Gd-DTPA solutions, are used as MRI oral contrast agents in gastrointestinal imaging.
- Superparamagnetic Contrast Agent – Used only for gastrointestinal tract imaging, this contrast agent is less soluble.
Different types of MRI Gastrointestinal Superparamagnetic Contrast Agents are Superparamagnetic Iron Oxide, Magnetite Albumin Microsphere and Oral Magnetic Particles