Clean mushroom caps then pat dry with a paper towel. Remove the stems, then use a spoon to slightly and carefully scrape out the gills. Place the mushroom cap side down, on a prepared baking sheet greased with cooking oil spray.
In a bowl mix the prepared rotini pasta, cream cheese, parmesan, bread crumbs, imitation crab, parsley and garlic. Fill the caps with about 2-3 tablespoons of the mix.