Carotid Ultrasound: Normal Values?

  My 65 year old mother recently had a bilateral carotid ultrasound in preparation for elective surgery, and the results are as follows:
  "The study demonstrates normal velocities bilaterally with a ratio of 1.2 on the right and 0.9 on the left consistent with 16-49% stenosis of the internal carotid arteries.  CONCLUSION: Bilateral 16-49% stenosis of the internal carotids."
  My questions: Is this within normal limits for someone of her age and, if it is, then what percentile stenosis is considered at risk for stroke?  Also, are there noninvasive ways to appreciably decrease the amount of stenosis?  Thank you very much.
  Sincerely,
  C.K.
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Dear C.K.:
The answer to your question depends on why the test was performed.  If your mother was having symptoms of stroke or mini-stroke, or whether it was just a routine test before surgery, would determine the appropriate treatment.  From your question, I am assuming the test was done not for symptoms, but just as a screening test.  In that case, the amount of blockage seen on the ultrasound would not require any surgical procedure.  An aspirin a day and cholesterol lowering medications may be appropriate, but would depend on her overall medical condition.  You should check with her doctor before starting any therapy.  
The amount of atherosclerosis in the heart arteries and carotid arteries increases with age.  I would not however equate this with

[patsy52]

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