ARRS 2022 Abstracts

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E1437. Contrast-Enhanced T1-Weighted MRI Aids Diagnostic Evaluation in Ulnar-Sided Injuries of the Triangular Fibrocartilage Complex
Authors
  1. Andreas Kunz; University Hospital Würzburg
  2. Jan-Peter Grunz; University Hospital Würzburg
Objective:
With its complex 3D structure, diagnosis of triangular fibrocartilage complex (TFCC) lesions remains a challenging task for radiologists. Originating from the sigmoid notch of the radius is the avascular central disc, whereas the peripheral TFCC is vascularized and consists of a deep and superficial lamina that insert in the ulnar fovea and at the ulnar styloid process, respectively. The aim of this study was to evaluate whether contrast-enhanced T1-weighted turbo spin echo (TSE) provides additional diagnostic value for the detection of TFCC injuries compared to plain T1 and T2-weighted MRI.

Materials and Methods:
Scan protocol included coronal and axial acquisition of T2 TSE, as well as coronal acquisition of T1 TSE before and after intravenous application of gadolinium. Two board-certified radiologists analyzed two randomized datasets for each examination in a blinded fashion. One set comprised only plain sequences, and the other contained additional contrast-enhanced T1-weighted TSE images. Observers assessed the condition of the articular disc and ulnar-sided TFCC periphery in dichotomous fashion, further stating their diagnostic confidence on a five-point scale. Based on signal intensity measurements in ROIs, contrast-to noise ratios (CNR) were calculated in each patient with any form of TFCC discontinuity.

Results:
Lesions of the articular disc and peripheral TFCC were present in 24 and 61 patients. Diagnostic sensitivity for central discus lesions was high, independent of access to gadolinium-enhanced sequences (unenhanced MRI: 0.96/0.96; contrast-enhanced MRI: 0.92/0.88). CNR was highest in T2-weighted sequences (unenhanced T1: 8.7; T2: 13.5; contrast-enhanced T1: 11.2; p < 0.001). For peripheral TFCC injuries, sensitivity (unenhanced MRI: 0.60/0.62; contrast-enhanced MRI: 0.89/0.91; p < 0.001) improved with the addition of contrast-enhanced T1 TSE; CNR was also superior after gadolinium application (unenhanced T1: 7.8; T2: 8.2; contrast-enhanced T1: 30.0; p < 0.001). Diagnostic confidence for ulnar-sided lesions increased when observers had access to contrast-enhanced T1 TSE (all p < 0.001). Interrater reliability indicated by Cohen's kappa was moderate in unenhanced MRI (0.56) and substantial for contrast-enhanced MRI (0.68).

Conclusion:
The ulnocarpal complex consists of several conjoint parts with different vascularization patterns that influence the available treatment in case of discontinuity. Functioning as the main stabilizer of the distal radioulnar joint, detection of TFCC injuries is important for assessing whether surgical refixation is necessary.