Boil a large pot of salted water and cook the pasta for 8-10 minutes until al dente. Drain and rinse under cold water.

Prepare shrimp by boiling in separate water for 2-3 minutes until pink, or chop pre-cooked shrimp.

Finely dice celery, red bell pepper, red onion, and chop parsley.

In a bowl, combine mayonnaise, sour cream, Dijon mustard, lemon juice, Old Bay seasoning, salt, and pepper. Whisk until smooth.

In a large bowl, combine pasta, shrimp, imitation crab, and vegetables. Add dressing and toss gently.

Cover and chill in the refrigerator for at least 1 hour before serving.