CT and MR imaging of carpal tunnel syndrome [CTS]

ABSTRACT

This study was undertaken to determine whether objective structural findings exist on CT and MR images that will permit [a] localization of the source of neurobogic findings to an entrapment of the median nerve in the carpal tunnel, [b] determination of the cause of CTS, and [c] identification of the cause of treatment failure. The CT [n = 18] and MR imaging [n = 18] Eighteen wrists in 13 no selected consecutive patients with clinical symptoms of carpal tunnel syndrome were studied over a 1-year period. Eight patients were women and five were men. They ranged in age from 25 to 54 years, with a mean age of 37 years. In four patients the symptoms were bilateral. In the remaining nine subjects with unilateral symptoms, the night hand was symptomatic in six and the left hand in three. All images were reviewed. Among the 18 standard MR imaging studies, compression of the median nerve was evident Diffuse swelling or segmental enlargement of the median nerve demonstrated [usually seen best at the level of the pisiform] [18 wrists]. The median nerve may flatten [usually demonstrated best at the level of the hamate]. Palmar bowing of the flexor retinaculum may be noted [usually demonstrated best at the level of the hamate] [17 wrists].The calcification were found in the floor of carpal tunnel [i.e., the space between the flexor tendons and the carpal bones] [18 wrists], in the carpal bones [17 wrists], in the radiocarpal joint [17 wrists], in the flexor tendons or tendon sheaths [nine wrists], and in the extensor tendons or tendon sheaths [16 wrists], especially the extensor carpi ulnaris. All the tophi manifested low to intermediate signal intensity compared with muscle, often containing small foci of very low signal intensity on T1-weighted spin-echo images Varying degrees of calcification were noted on CT and MR imaging studies. Gadolinium-enhanced MR studies showed heterogeneous enhancement. Is useful for its ability to display and evaluate the cross-sectional volume of the carpal tunnel and for detecting subtle calcification in the tendons within the canal. CT also provides an excellent tool for evaluating the carnal bones through multiplanar and 3- dimensional reconstructions but CT is limited in its ability to visualize the median nerve and tendons of the carpal tunnel well enough to allow definitive differential diagnoses to be rendered. Therefore, MRI is the best method of visualizing the soft tissues of the carpal tunnel