Fig. 5 US-guided anterior ap- proach. a Sonogram of a right- hand shoulder showing the needle track (arrows) from lateral to medial with the USa approach. The needle is inserted at the level of the coracoid (C). The tip of the needle is in intra-articular posi- tion with the tip underneath the subscapular tendon (SSC) and bordering the humeral head (H). b Corresponding cadaver section showing the optimal needle track (white line) Time assessment To be able to monitor the time taken for the procedure in four different centres, with different personel, a simple method of scoring how things were done was standardised. Room time (time between the patient entering and leaving the room), radiologist time (time between entering and leaving the room) and procedure time (time between starting and ending the injection procedure) were recorded. Mean times were assessed, and because of the maximum time of Fla and Flp, we also assessed the median times (Table 3). 725 Evaluation of intra-articular administration of contrast material The number of attempts needed to enter the joint space was recorded. An attempt to inject a joint was defined as the need for repositioning of the needle after unsuccessful test injection. The joint space was considered to be entered when the needle contacted the humeral head cartilage, test injection was performed without resistance and the intra-articular position of contrast material was confirmed with fluoros- copy by injection of 1–2 ml iodinated nonionic contrast (Omnipaque 300; Amersham Cygne, Eindhoven, The Fig. 6 US-guided posterior approach. a Sonogram of a right-hand shoulder showing the needle track (arrows) from lateral to medial with the USp approach. The needle is inserted at the midlevel of the humeral head (H). The needle is in intra-articular position with the tip underneath the infraspinatus tendon (ISP) and posterior labrum (L) and bordering the hyaline cartilage (asterisks) of the humeral head. G: glenoid. b Corresponding cadaver section showing the optimal needle track (white line). c Sonogram following injection of 15 ml injected gadoterate meglumine (Artirem®) (asterisk). The correct intra-articular position of the needle (arrows) can be visualised real-time during injection, but is also confirmed by the ‘comma’-like configuration of the posterior labrum (arrowheads), which is lifted by the intra-articularly injected fluid (asterisk). G: glenoid, H: humearal head, ISP: infraspinatus tendon