HIGH FIELD MRI
Magnetic Resonance Imaging (MRI) is a method of obtaining detailed pictures of internal body structures without the use of radiation or radioactive substances of any kind. This is accomplished by placing the patient in a magnetic field while harmless radio waves are turned on and off. This causes the body to emit its own weak radio signals which vary according to tissue characteristics. These signals are then picked up by a sensitive antenna and fed to a computer which produces detailed images of the body for interpretation by trained radiologists.
High Field MRI utilizes a cylindrical tube in which the magnet is enclosed. Patients are placed in the unit lying down, either head first or feet first. Since this configuration produces optimum magnetic field strength, the signal and images produced are of the highest quality. HF MRI exams usually take 20 – 30 minutes.
You can help to produce a high quality image by lying still during the examination while breathing normally. The average scan takes 5 to 15 minutes – the complete examination about 30 to 45 minutes – during which several dozen images will be produced.
Types of scans that should be performed on a high field scanner include:
• Temporomandibular joints (TMJ)
• Brain – Sella
• Liver and pancreas
• Non-Brain MRA (i.e. aorta)
• Recent CVA
• Patients in severe pain or who can’t hold still
Conventional high field Magnetic Resonance Imaging systems usually operate at stronger field strengths than open MRI systems and typically provide clearer, more detailed and easier to read scans. On a high field or closed MRI system, the slices can be thinner, improving the information the physician uses to diagnose the problem.
High field MRI units may also take less time due to the higher magnetic field strength. High field scans can be one and a half to two times faster than an “open” scan. High field Magnetic Resonance Imaging scanners also provide the most advanced imaging techniques, some of which cannot be performed on an open scanner. Many optional accessories are available.
High field MRI systems are indicated for central nervous system and vascular studies – particularly contrast enhanced Magnetic Resonance Angiography (MRA) studies, abdominal work that requires the patient to hold their breath, fat saturation techniques, certain cancer studies and any study that requires the highest resolution.