Imaging of the Achilles tendon in spondyloarthritis: a comparison of ultrasound and conventional, short and ultrashort echo time MRI with and without intravenous contrast. - Hodgson, R; Grainger, A; O'Connor, P; Evans, R; Coates, L; Marzo-Ortega, H; Helliwell, P; McGonagle, D; Emery, P; Robson, M (European radiology, 2011)