Jung-Ah Choi MD, Abstract Co-Author: Nothing to Disclose

Jang Gyu Cha MD, Abstract Co-Author: Nothing to Disclose

Guen Young Lee, Presenter: Nothing to Disclose

Marc Safran MD, Abstract Co-Author: Nothing to Disclose

Garry Evan Gold MD, MSEE, Abstract Co-Author: Consultant, Zimmer Holdings, Inc Consultant, ICON plc Consultant, ArthroCare Corporation Research support, General Electric Company

To evaluate the intactness and signal intensity (SI) of ligamentum teres on direct MRA in patients with clinically suspected FAI and correlate them with arthroscopic findings.

We retrospectively evaluated 162 consecutive direct MRAs that were performed in 2009. Three experienced radiologists evaluated the intactness as present and intact vs. probable high grade or complete tear. and SI of LT on T1- and PDWI on axial and coronal T1-weighted images (WI). One of the three radiologists evaluated axial and coronal dimensions on axial and coronal T1WI. SI were coded as compared to articular cartilage SI for absent, low, iso, high as as 0, 1, 2, 3, respectively. Interobserver agreement regarding intactness of ligamentum teres on MRA was assessed using Kappa values. 77 patients underwent arthroscopic surgery under the clinical impression of FAI by a single experienced orthopedic surgeon, of which the findings were correlated with MRA findings; sensitivity and specificity were obtained.

Out of a total of 77 cases that underwent arthroscopic surgery, there were 5 cases where the LT was completely absent or attenuated to a degree that measurement could not be taken on MR arthrography. On arthroscopy, there were 5 cases with complete tear and 5 with partial tear of the LT. The kappa values for intactness of LT were 0.8821, 0.8505, 0.7372 for observers 1vs.2, 1vs.3, 2vs.3, respectively. The overall average SI was 1.42 and 1.26 on T1- and PDWI, respectively. The kappa values for SI on T1WI were 0.5329, 0.5029, 0.4394, and on PDWI were 0.5615, 0.5849, 0.4468 for observers 1vs.2, 1vs.3, 2vs.3, respectively. Sensitivity was 20.00% (95% CI 3.62%-62.45%) and specificity was 95.83% (95% CI 88.45% - 98.57%).

The evaluation of LT on MRA showed high specificity but low sensitivity when correlated with arthroscopic findings. The interobserver reliability on intactness of LT on MRA was very good although the interobserver reliability on SI of LT was moderate.

MR arthrography shows high interobserver reliability on evaluation of intactness of ligamentum teres and high specificity when correlated with arthroscopy but low sensitivity.

Choi, J, Cha, J, Lee, G, Safran, M, Gold, G, Evaluation of Ligamentum Teres (LT) on MR Arthrography (MRA) in Patients with Clinically Suspected FAI: With Arthroscopic Correlation.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11010512.html