Carpal tunnel syndrome(CTS), a type of median nerve neuropathies, is the most common peripheral nerve entrapment syndrome. Most cases are idiopathic but CTS can be associated with rheumatologic disorders. There isn't any gold standard technique in diagnosis of CTS. Electrodiagnostic studies (EDS) are usually performed to confirm diagnose, to differentiate other diseases or to detect severity. But EDS have some disadvantages such as EDS are time consuming, uncomfortable, may require interventional procedures, can not directly assess the anatomy of the median nerve and its surrounding structures. For these reasons, the use of ultrasonography (US) in the diagnosis of carpal tunnel syndrome has been investigated for a long time. Most of them focused on the cross-sectional area(CSA) of median nerve. Fewer studies have investigated the vascularity of the median nerve. But there is conflict results because conventional Doppler techniques may fail to show small vessels or slow blood flow. Superb microvascular imaging (SMI) is a new ultrasound technology that can diferentiate blood flow signals from artifacts by using a new algorithm. In carpal tunnel syndrome hypervasularitation of median nerve has showed by SMI. To our best knowledge, there isn't any study assessing median nerve hypervascularity by using SMI in PsA. So we aimed to investigate median nerve hypervasculatitation in psoriatic arthritis (PsA) patients with CTS or without CTS by using SMI, then compare them with normal people.
