A 50 year old female's carotid ultrasound reported mild plaque. Her cholesterol etc. Are good. Previously, she had high homocysteine level. Is any treatment needed at this time?

Carotid stenosis. We don't worry until "severe" description of the plaques, occluded 95%. At this point the risk increases for plaque to break off and cause a stroke. There is no indication to treat the "mild" condition. Be sure to control any hypertension, keep your cholesterol at goal, and take a 81mg Aspirin everyday after age 50 if you physician recommends it based on your risk factors.
Carotid plaque embol. You may not need worry about unless 80% or more stenosis, when think about doing balloon angioplasty or open endarterectomy. Stroke can develop when blood clot around the plaque emboli to distal arteries, not the plaque itself. Many patient can have ulcerated plaque which can make blood clot easier than no ulceration. In this situation, it needs to be taken care of even moderate stenosis.
Plaque. The presence of plaque alone is a sign that steps against atherosclotic disease are appropriate. Diet, exercise, Aspirin and statin should be considered. If diabetes ornhypertension are present those too need rx. Discuss with your dr.
Not specifically. The ultrasound is normal for age. Elevated homocysteine alone is not a great risk factor for plaque progression. Control Blood pressure, cholesterol, exercise and DON'T SMOKE! Aspirin 81 mgm per day is also a good idea.