Preheat the oven to 350°F. Cook the macaroni in boiling, salted water until done. Drain and rinse with hot water. In a 1-1/2 quart casserole dish, whisk the soup with the milk until smooth. Stir in the drained tuna and parsley until well blended. Toss in the cooked noodles and stir until coated. Top the casserole with the buttered crumbs. Bake at 350°F. for 30 minutes. Serves 6.