67 © ISAKOS 2020 G. Bain et al. (eds.), Surgical Techniques for Trauma and Sports Related Injuries of the Elbow, https://doi.org/10.1007/978-3-662-58931-1_7 4D-CT and Dynamic MRI Assessment of Elbow Disorders Simon Bruce Murdoch MacLean, Renee Carr, and Gregory Bain 7.1 Introduction Since its introduction in 1973, conventional com- puted tomography (CT) imaging has provided a static display of a joint or organ. Four-dimensional CT scanning combines the added dimension of time. 4D-CT scanning has already reported to be of proven beneft in the respiratory, gastrointesti- nal, cardiac, and neurosurgical specialties. Within orthopedic surgery, 4D-CT scanning has been used for the diagnosis and surgical planning of femoroacetabular impingement, thoracic outlet syndrome due to costoclavicular impingement, scapholunate instability, capitate subluxation, pisotriquetral instability, acromioclavicular dis- location, and snapping scapula [1–7]. 4D-CT scanning of the elbow has not been described in the literature to our knowledge. 4D-CT scanning is created when a 3D-CT vol- ume containing a moving structure is imaged over a defned period of time, creating a dynamic vol- ume data set. This can allow for dynamic assess- ment of joint kinematics, such as in the symptomatic elbow. In our unit, images are acquired using a 320-slice multidetector CT scan- ner (Aquilion One, Toshiba Medical Systems, Inc., Tochigi-ken, Japan). The feld of view (z-axis) includes the entire elbow. Table movement is not necessary as the gantry provides 16 cm of z-axis volume using 0.5 mm detectors. This compares to traditional 64-slice CT scanners, which have only 4 cm coverage. If the scanning table is kept still while scanning, then the objects up to 16 cm in size can be moved and assessed over time. Post- processing allows the desired region of interest to be analyzed in 2D, 3D, or 4D. In our department, we use 4D-CT scanning for patients with complex wrist and elbow pathol- ogy, where we are concerned there may be a dynamic component to their problem. In the elbow, these patients include those with undiag- nosed elbow symptoms: pain, instability, or impingement symptoms. We also use the tech- nology for surgical planning. Elbow movements in the gantry include full fexion-extension and full pro-supination in the fexed and extended position. We compare the asymptomatic normal side to the pathological side. The patient has a “trial run” outside of the scanner until they are 7 S. B. M. MacLean (*) Department of Orthopaedic Surgery, Tauranga Hospital, Bay of Plenty, New Zealand G. Bain School of Medicine, Flinders University, Adelaide, SA, Australia Department of Orthopaedic Surgery, Flinders Medical Centre, Adelaide, SA, Australia R. Carr School of Medicine, Flinders University, Adelaide, SA, Australia Electronic Supplementary Material The online version of this chapter (https://doi.org/10.1007/978-3-662-58931- 1_7) contains supplementary material, which is available to authorized users.