Susceptibility Weighted Imaging in Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) can be classified as a loss of consciousness and/or confusion and disorientation is shorter than 30 minutes.  While MRI and CAT scans are often normal, the individual has cognitive problems such as headache, memory problems, attention deficits,  mood swings and frustration.  While the condition may be called “mild,” the effects can be devastating. This week’s paper discusses findings in mTBI subjects with a sensitive MRI sequence called susceptibility weighted imaging (SWI) which can detect subtle findings such as venous damage, and cerebral microbleeds when other scanning modalities cannot.

Susceptibility weighted MRI in mild TBI, Huang et al. Neurology, 2015

SWI images depecting microbleeds (white arrows).

In Neurology Today, a review of SWI in mTBI appears by Richard Robinson. He interviewed Dr. Chi-Jen Chen from Taipei University and Mark Fisher from UCI. According to Huang et al, cerebral microbleeds (CMBs) are common in mTBI as seen by SWI. Although many mTBI patients recover well, there is a cohort who suffer from prolonged disability. There has been a lack of imaging biomarkers as prognostic factors for mTBI.  A separate editorial appears by Drs. Haehnel and Herweth about the role of SWI in detecting CMBs in mTBI. SWI is a method developed by Prof. E. Mark Haacke and is exquisitely sensitive to venous blood and blood products such as hemosiderin (which is the major constituent of CMBs).

Dr. Chen enrolled 111 patients and age matched controls who were negative for hemorrhage on CT and conventional MRI. They found 60 CMBs in 26 patients and only 15 CMBs in 12 healthy controls. In mTBI patients, 87% were in the cortex and sub-cortical white matter while only 20% of the CMBs in healthy controls were in the same region. The rest were in the deep gray matter and may have been associated with hypertension.

Dr. Chen suggests that CMBs may serve as a biomarker for mTBI. They found that there was a correlation with neuropsychological testing for memory and the number of CMBs.  

Dr. Fisher suggested that further work be done to see if there is an association of CMBs with loss of consciousness, fMRI results and age.

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MR Innovations is on the cutting edge of detection, location, and quantification of cerebral microbleeds. For more information on SWI and MRI post-processing and analysis, please visit www.mrinnovations.com.

References:

1.    Huang YL, Kuo YS, Tseng YC, Chen DY, Chiu WT, Chen CJ. Susceptibility-weighted MRI in mild traumatic brain injury. Neurology. 2015 Feb 10;84(6):580-5.