Parkside Magnetic Resonance Center

Diffusion Imaging in Brain Attack... Now at Parkside MR Center

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76 year old woman with acute onset left sided weakness. (Left) CT scan shows no abnormality. (Right) Diffusion MR image demonstrates right thalamic infarct.

6 day old infant with seizures. (Left) T-2 weighted MR image shows subtle changes in the left parietal region. (Right) Diffusion image demonstrates obvious acute stroke.

83 year old man with a history of a recent fall. (Left) Routine FLAIR image shows extensive white matter signal abnormality of indeterminate age. (Right) Diffusion image reveals areas of acute stroke in the distribution of the left anterior cerebral artery.

79 year old with sudden onset of slurred speech. (Left) Diffusion image performed at time of symptom onset demonstrates acute infarct. (Right) Follow up exam performed 15 days later shows the lesion is much less apparent due to partial resolution of the diffusion abnormality.

Imaging Breakthrough

"Diffusion imaging of the brain is a new technique which analyzes the diffusion characteristics of water molecules within tissues to produce images. These images have the unique ability to distinguish acute lesions from old lesions. Alterations in the diffusion characteristics of water occur very soon after the onset of brain injury and diffusion imaging can detect these changes as early as 15 minutes following ictus. In addition to early detection, the ability to specifically identify the acute lesion can influence the course of treatment. If the acute lesion is demonstrated in a territory compatible with an embolic etiology, then the diagnostic work-up will proceed to identify the source of emboli. However, diffusion images may demonstrate the acute lesion to lie in a territory in which the most likely etiology is small vessel disease, not emboli. In these cases a prolonged and costly work-up for an embolic source can be avoided."

Joseph H. Introcaso, M.D., D.M.D.
Acting Chairman, Department of Radiology
Lutheran General Hospital

Discussion

Diffusion weighted MR images detect subtle differences in free water movement between normal and acutely infarcted brain tissue. These differences are conspicuous on diffusion weighted images in as little as 15 minutes and fade gradually over the following two weeks [1].

With advances in thrombolytic therapy and neuroprotective agents in the treatment of stroke, the optimal MR protocol is expanding to include routine use of diffusion weighted imaging [2]. At Parkside MR Center, diffusion MR imaging is providing our referring physicians a whole new dimension in the early detection of brain attack.

If you would like more information about Diffusion Imaging, please contact Parkside MR Center at (847) 696-7900.

References

1. Burdette, J., Ricci, P., Pettitti, N., Elster A. Cerebral infarction: Time course of signal intensity changes on diffusion weighted MR images. AJR 1998;171: 791-795.

2. Beauchamp, N., Byran, R. Acute cerebral ischemic infarction: A pathophysiological review and radiologic perspective. AJR 1998;171: 73-84

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