UTE-T2* versus conventional T2* mapping to assess posterior cruciate ligament ultrastructure and integrity-an in-situ study

Lena Marie Wilms; Karl Ludger Radke; David Latz; Thomas Andreas Thiel; Miriam Frenken; Benedikt Kamp; Timm Joachim Filler; Armin Michael Nagel; Anja Müller-Lutz; Daniel Benjamin Abrar; Sven Nebelung

doi:10.21037/qims-22-251

UTE-T2* versus conventional T2* mapping to assess posterior cruciate ligament ultrastructure and integrity-an in-situ study

Quant Imaging Med Surg. 2022 Aug;12(8):4190-4201. doi: 10.21037/qims-22-251.

Authors

Affiliations

¹ Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Dusseldorf, Germany.
² Department of Orthopaedics and Trauma Surgery, Medical Faculty, University Dusseldorf, Dusseldorf, Germany.
³ Institute for Anatomy I, Heinrich-Heine-University, Dusseldorf, Germany.
⁴ Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
⁵ Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
⁶ Department of Diagnostic and Interventional Radiology, University Hospital Aachen, Aachen, Germany.

Abstract

Background: Clinical-standard morphologic magnetic resonance imaging (MRI) is limited in the refined diagnosis of posterior cruciate ligament (PCL) injuries. Quantitative MRI sequences such as ultrashort echo-time (UTE)-T2* mapping or conventional T2* mapping have been theorized to quantify ligament (ultra-) structure and integrity beyond morphology. This study evaluates their diagnostic potential in identifying and differentiating partial and complete PCL injuries in a standardized graded injury model.

Methods: Ten human cadaveric knee joint specimens were imaged on a clinical 3.0 T MRI scanner using morphologic, conventional T2* mapping, and UTE-T2* mapping sequences before and after standardized arthroscopic partial and complete PCL transection. Following manual segmentation, quantitative T2* and underlying texture features (i.e., energy, homogeneity, and variance) were analyzed for each specimen and PCL condition, both for the entire PCL and its subregions. For statistical analysis, Friedman's test followed by Dunn's multiple comparison test was used against the level of significance of P≤0.01.

Results: For the entire PCL, T2* was significantly increased as a function of injury when acquired with the UTE-T2* sequence [entire PCL: 11.1±3.1 ms (intact); 10.9±4.6 ms (partial); 14.3±4.9 ms (complete); P<0.001], but not when acquired with the conventional T2* sequence [entire PCL: 10.0±3.2 ms (intact); 11.4±6.2 ms (partial); 15.5±7.8 ms (complete); P=0.046]. The PCL subregions and texture variables showed variable changes indicative of injury-associated disorganization.

Conclusions: In contrast to the conventional T2* mapping, UTE-T2* mapping is more receptive in the detection of structural damage of the PCL and allows quantitative assessment of ligament (ultra-)structure and integrity that may help to improve diagnostic differentiation of distinct injury states. Once further substantiated beyond the in-situ setting, UTE-T2* mapping may refine diagnostic evaluation of PCL injuries and -possibly- monitor ligament healing, ageing, degeneration, and inflammation.

Keywords: Magnetic resonance imaging (MRI); knee joint instability; posterior cruciate ligament (PCL); quantitative imaging; ultrashort echo-time (UTE)-T2*.