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Home > Press Center > New Brain Lesions Appear on Magnetic Resonance

Contact:
Emily Kalata
Assistant Director, Communications
312.334.2309

Researchers from San Francisco, have recently published a study regarding patients who had brain imaging (diffusion weighted MRI or DWI) before and after carotid artery stenting (CAS), to determine if there were new lesions in patient's brains following the procedure.

Angioplasty and stenting fractures the atherosclerotic plaque as it pushes the plaque out of the way. To prevent plaque fragments from traveling to the brain protective distal filtration devices are used during CAS. However, some fragments do reach the brain and although strokes after these procedures are unusual, imaging using DWI does show small areas of damage. "These lesions do not cause symptoms, but obviously are of concern,” said Joseph H. Rapp, MD, from the vascular surgery service at the San Francisco Department of Veterans Affairs Medical Center. Studies with Doppler ultrasound have shown that fragments of plaque can be released from the area treated by CAS for several days after the procedure. Dr. Rapp and his colleagues asked if these fragments can cause damaged areas and if imaging early after the procedure would underestimate the number of these "silent" lesions after CAS. 

There were 54 CAS procedures done in men from the ages of 59 to 83 years. All had DWI prior to the procedure to make sure the lesions seen were new. After 23 of these procedures, DWI was done one hour after CAS and new lesions were found after only two of these 23 CAS cases (8.7 percent). When DWI was done at 48 hours, there were new lesions in 36 of the 54 procedures (67 percent). The new lesions were almost always on the same side as the CAS procedure. The MRIs included axial and coronal DWI and fluid-attenuated inversion recovery images, and were read by two neuroradiologists who were blinded to the timing of the study.

The results of the study, published in the May 2007 issue of the Journal of Vascular Surgery, noted that there only were two peri-procedural strokes (3.7 percent) and both patients completely recovered. There also was one transient ischemic attack (TIA), but no strokes or TIAs during follow-up. The median number of DWI lesions was four (range, 1 to 17). Most measured 1 to 2 mm in diameter, with the largest lesion measuring 7 mm.

Every filtering device examined in the study contained plaque fragments, but they, along with the degree of stenosis, size of the angioplasty balloons used (or number of inflations) had no correlation with post-procedure DWI findings.

“Although our patients had excellent clinical outcomes and the importance of these "silent" brain lesions seen on DWI is not clear, we would certainly like to avoid them if possible," said Dr. Rapp. "To do this, new approaches may need to be developed to prevent microembolization following the CAS procedure."