Faisal Siddique Raja BSc, MD, Presenter: Nothing to Disclose

Gregory J. Garvin MD, Abstract Co-Author: Nothing to Disclose

Said Osman MD, Abstract Co-Author: Nothing to Disclose

Mustafa Zafar Khan MD, Abstract Co-Author: Nothing to Disclose

To describe the spectrum and prevalence of abnormalities related to the extensor carpi ulnaris (ECU) tendon in asymptomatic wrists on magnetic resonance imaging (MRI).

MRI was performed on the wrists of 103 asymptomatic volunteers at 1.89T. Coronal T1, proton density (PD), T2, and inversion recovery (IR) as well as sagittal IR, axial T1, and axial IR weighted images were obtained. Images were assessed for adequacy of ECU tendon demonstration, as well as abnormal signal intensity and its characterization and ECU tendon position. All images were read independently by two musculoskeletal radiologists and one musculoskeletal radiology fellow. Chi-squared analysis was used to determine the difference between the observers.

Of the 103 patient examinations, 99 yielded images suitable for ECU evaluation. 65 patients demonstrated abnormal signal intensity (SI) involving their ECU tendons; 6 greater than fluid SI and 59 less than fluid SI. 15 scans were interpreted as showing a tear involving the ECU tendon, 4 of which were complete tears and 11 were partial. The remaining 50 patients had some degree of tendinosis, with mild tendinosis seen in 45 patients and moderate in 4 patients. For the patients with ECU tendon abnormality with SI less than fluid, 34 were characterized as linear, 13 as globular, and 12 as linear/globular. All of these values represent means, with no significant difference between observers. A mean of 45 patients were described as having ECU tendon SI abnormality that communicated with the articular surface, and 14 that did not (significant inter-observer difference, p=0.015). ECU tendon position was described as normal in 70 cases, subluxed in 27 and dislocated in 2 (significant inter-observer difference, p=0.002).

A clear majority (65 percent) of these asymptomatic wrists demonstrated MRI abnormalities with respect to the ECU tendon. The most common abnormality was MRI findings suggestive of tendinosis, affecting 50 percent, the vast majority of which were described as “mild tendinosis”. 15 percent of scans showed MRI findings consistent with an ECU tendon tear. No statistically significant inter-observer difference was noted.

Given the high prevalence of incidental ECU tendon MRI abnormalities, these findings need to be correlated with the patient's actual clinical symptoms to determine whether they are truly relevant.

Raja, F, Garvin, G, Osman, S, Khan, M, Prevalence and Spectrum of Magnetic Resonance Imaging (MRI) Findings Involving the Extensor Carpi Ulnaris (ECU) Tendon in Asymptomatic Wrists.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034533.html