Cut smoked sausage into 1/4-inch-thick slices. Cook in a large Dutch oven over medium-high heat 8 to 10 minutes or until slices are browned. Remove sausage, and drain on paper towels, reserving 1 teaspoon drippings in pan.
Sauté onion and celery in hot drippings in Dutch oven over medium-high heat 4 to 5 minutes; stir in garlic, 1/2 teaspoon Cajun seasoning, and rice; sauté 3 minutes. Stir in broth, next 3 ingredients, and remaining 1 1/2 teaspoons Cajun seasoning. Bring to a boil; cover, reduce heat, and simmer 15 to 20 minutes. Remove from heat; stir in sausage and parsley; let stand, covered, 10 more minutes or until rice is tender. Serve with hot sauce, if desired.