A comparison of the Accuracy of Ultrasound and Computed Tomography in common diagnoses causing acute abdominal pain - van Randen, A; Laméris, W; van Es, H W; van Heesewijk, H P; van Ramshorst, B; Ten Hove, W; Bouma, W H; van Leeuwen, M S; van Keulen, E M; Bossuyt, P M; Stoker, J; Boermeester, M AOPTIMA Study Group (Eur Radiol, 2011)