By: Dr. Chao

3T-MRI really is the best way to do MRI. “T” for “tesla” is a measure of a magnetic field’s strength. How strong is your MRI? 3T is the strongest magnet available for clinical use in MRI scanners and there is only one in the entire State of Delaware. Simply put: the stronger the magnet, the better the images. Also, the stronger the magnet, the faster the scan. This is particularly important for Ophthalmologists and Optometrists. The visual processing pathway is extremely complex and problems can manifest themselves as decreased visual acuity or vision loss—medical emergencies. 3T MRI can diagnose giant cell arteritis non-invasively, which is ONLY possible when using 1024×1024 matrix resolution (1 megapixel) with contrast. Other MRI scanners can only scan with 0.25 megapixel—if that.

3T yields faster, more detailed images more safely and uses smaller doses of contrast—a dye injected to ensure sharper contrast. All this combines to make 3T the best way to image the brain and optic nerves. Orbits require the thinnest sections possible—as does MS—and 3T can scan 1mm thick sections. Our scanner takes 1mm thick images of the entire brain in only 7 minutes—technically impossible for any non-3T scanner. Fat saturation images reduce signal from fat, allowing us to see subtle inflammation around the optic nerve in DEVIC’s disease.

Done properly, an ORBIT study is not only images of the brain; it includes the Brain, Posterior fossa, Cranial nerves and Orbits—before and after contrast with fat saturation. Essentially, a triple study. Most imaging centers eliminate a series or two to shorten scanning time. A true study of the brain, orbits, MRA of the vessels, and cranial nerves before and after contrast would take about 90 minutes—even on high field 1.5T systems. At 3T, it takes less than an hour.

3T is particularly useful for detecting demyelinating plaques. Because 3T lets us scan with thinner slices and higher resolution, we see more plaques. Detecting 1-2mn plaques requires the use of 1mm thick sections. 3T shows up to twice as many plaques as any less powerful scanner. And, be advised that reimbursements for 3T scans are no different than for weaker MRI scans. Patients do not pay more for 3T.

In the early 1990’s, Japanese corporations developed software and permanent magnets at 0.3T and ingeniously marketed them as OPEN MRI scanners. While these units do have openings along the side of the bore of the scanner, the actual space for the patient is narrower than other, high field MRI scanners. Years later, OPEN MRI still enjoys some success in competing with 1.5T and 3T-MRI units due to this clever marketing. Little mention, however, is made of the fact that their magnet strength is no longer competitive (0.3T v. 3T).

While a Fellow at the University of Pennsylvania, I taught that CT (computerized tomography) studies of the brain and spine were sub-optimal. CT lacks the detail of MRI and misses so many things that it is amazing that it is ever ordered for brain and spine. A positive brain CT leads to an MRI for more detail. A negative CT also leads to an MRI just to make sure. So, the CT study is essentially superfluous—a waste of everyone’s time and the patient’s money. A CT of the orbits and brain fails to “see” most causes of blindness. Demyelination, superficial temporal arteritis and even optic nerve lesions and orbital pseudotumor are routinely missed. Because of its low magnet strength, this is also true for OPEN MRI. In Germany, OPEN MRI’s have been banned for this very reason!

Most patients are unaware that MRI scanners have different strengths. They have no idea that the strength of an MRI scanner’s magnet determines the quality of the images used in making a iagnosis. Cancerous tumors might simply not be seen! To most people, an MRI is an MRI. But, not all MRIs are created equal. OPEN MRI machines are definitely inferior. In terms of physics, the “signal to noise” (a measure of the elements used to create an MRI image—a bit like talking about “pixels” in a digital camera) of an OPEN MRI is one-tenth that of a 3T MRI. Think about it. In order to obtain the same quality on an OPEN MRI, you might have to scan 100 times longer. Even a high field 1.5 unit is 2-4 times inferior to 3T. And, 3T-MRI has been shown to catch lesions missed by both 0.3T OPEN MRI and 1.5T MRI scanners! I recently saw a large cerebral aneurysm, missed by OPEN MRI. If it had burst, it might well have been fatal. 1.5T MRI missed a case of multiple brain lesions. 1.5T MRI missed subtle bleeding in the brain.

An accurate diagnosis depends on getting the best test possible. If you need an MRI, have it done on the very best machine available. The first time. Why waste time and money on inferior tests? Be sure from the beginning. 3T-MRI is better than CT and OPEN MRI. Get the best. Use 3T-MRI. (www.3t-mri.net)

Dr. Philip Chao graduated Phi Beta Kappa from Yale University and was Scholar of the House. He continued his studies at the University of Rochester School of Medicine and Dentistry, receiving his medical degree in 1983. After a transitional internship year at the Mary Imogene Bassett Hospital in Cooperstown NY, Dr. Chao did his residency in Radiology at Brooklyn’s SUNY Health Science Center (1984-1987), where he became Chief Resident. He stayed on to complete a fellowship in Neuroradiology (1987-1988). Dr. Chao has been interested in MRI technology since its very beginning—the first MRI scan took place in 1981 while he was pursuing his medical studies. The University of Pennsylvania, where Dr. Chao was both a Body MRI Fellow (1988-1990) and a Neuroradiology Fellow (1989-1990), was at the heart of the development of this technology and Dr. Chao was able to work with pioneers in MRI on the first GE Signa 1.5T (tesla) scanner. His advanced research and specializations complete, Dr. Chao left the University of Pennsylvania for a position as Director of MRI in Wilmington DE—a position he held for 14 years. Dr. Chao eventually left that position to create the best MRI center in Delaware, using the very latest technology: 3T MRI. While 3T (tesla) scanners have been used for scanning research patients since 2002, these advanced, more powerful MRI scanners only became available for clinical use in 2004. Dr. Chao worked hard to bring 3T technology to Delaware and in February 2007, MRI Consultants, LLC began operating the first 3T scanner in the State. 3T is the newest horizon for MRI.

For more information, contact MRIConsultants at 302.295.3367 or 302.295. 0467.