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A Warning About White Matter Damage

I recently gave a lecture at the North American Brain Injury Society (NABIS) speaking about what many perceive as a widespread problem in our health care system involving TBI. The problem is that most radiologists in the United States have decided they do not want to be involved in TBI cases. Why do I say this and what does it mean? Let me explain:

1. The most common method of brain injury in the world arising from trauma is called Diffuse Axonal Injury (DAI). This occurs when the brain is subjected to rapid acceleration or deceleration though a high speed motor vehicle accident, for example. We now know that DAI can and does occur in the full spectrum of TBI – from mild to severe. However, the fact that DAI occurs in mild to moderate TBI is a fairly recent finding and many radiologists were not trained to know this.

2. Radiologists, like other physicians, are supposed to attempt to identify the illness or cause of illness through a process known as “differential diagnosis.” This is done by ruling out different possible causes of, say, an abnormality shown in the brain on MRI, until a proven cause can be found.

3. The problem arises when identifying an abnormality on brain MRI known as “white matter hyperintensities” (WMH). These small white areas on an MRI are what damage due to DAI looks like, but there are numerous other non-traumatic causes for WMH. These include: the aging process (starting at 45 to 50); smoking; high blood pressure; Lymes disease; Lupus; vasculitis; migraines, headaches, some mental disorders; and MS.

4. The problem is that currently a radiologist will identify WMH on an MRI following a patient’s trauma but will describe the findings as “non-specific.” That means that there are many causes for the abnormality – not that there is no abnormality. Sometimes following this statement the radiologist will give a short list of possible causes, most commonly “demyelinating disease” (MS), migraine, or ischemic disease (vascular degeneration). But what they will generally not say is that another possibility is trauma.

5. It is therefore imperative that someone who has suffered a TBI and has ongoing symptoms for more than six months to be able to conclude that the brain MRI is not showing an undiagnosed TBI. How do you do this? Certainly if a person is under the age of 45, and has no history of the above conditions, then trauma should be suspected. A comprehensive blood test can be ordered which can help rule in or rule out certain autoimmune diseases, Lyme disease, Lupus, and other possible causes.

6. It is also important for your treating physician to talk to you about where these WMH’s are in your MRI. Location is vitally important in determining the cause of WMH. If they are described as being located in the “deep white matter” then they are less likely to be caused by trauma than by one of the above conditions. However, if they are located at the gray-white junction, than trauma should be suspected. Brain injury occurs in this region due to the differential indensity between the gray matter (which is like the thick skin of a grapefruit) and the white matter, which are the long fibers that connect different areas of the brain together (the inside of the grapefruit). Because of this differential, when the brain is twisted or shaken the white matter often shows damage close to this area. In fact, a recent study in China of over 700 healthy 60 to 64-year olds showed zero WMH within four millimeters of the gray white junction. We can therefore infer that following a trauma, abnormalities found in this region are due to trauma. Even if 10% of the WMH are in this area, it would be consistent with trauma. Be aware that your treating radiologist and/or lawyer will not be aware of this information.

What can be done? A film can be reread by another radiologist. A better scan of the brain can be obtained. By this I mean an MRI that has a 3.0 teslor magnet instead of a 1.5. an MRI that includes Susceptibility Weighted Imaging (SWI), as well as Diffuse Tensor Imaging (DTI). SWI can identify tiny microhemorrhages in the brain which, not coincidently, look like WMH. Survivors of severe brain trauma can have hundreds of these microhemorrhages show up on SWI, whereas zero or only a few show up on standard MRI. DTI looks at white matter injury and a description of DTI can be found on the DTI page of this website.
The single most important thing in brain injury litigation is objectification of injury. Once there is a picture of damage to the brain, the tables are turned on the insurance company. They can no longer call the victim crazy, a liar, a drug addict so easily. A picture is indeed worth a thousand words.