Role of DWI in Assessment of Anterior Cruciate Ligament Pathology

Abstract Background The anterior cruciate ligament (ACL) is an important structure in maintaining the normal stability of the knee, yet with anterior cruciate ligament being the most commonly injured ligament, differentiation between complete and incomplete tears is crucial to provide non-operative management in incomplete tears patients. Magnetic resonance imaging (MRI) of the knee joint is routinely performed for the diagnosis of tear of cruciate ligaments. However, in some cases, is tough because the ligament fibers maybe obscured by edema. Ligament fibers have been shown to be better visualized on diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) mapping and therefore, ADC mapping may be able to verify if the ligament is continuous or not for accurate diagnosis of incomplete tears. Objective To determine the role of diffusion-weighted (DW) magnetic resonance imaging (MRI) in diagnosing and differentiating between complete and partial anterior cruciate ligament (ACL) tears and to compare it with conventional MRI sequences. Methods This is a prospective study approved by Ain Shams university ethics committee was conducted on 20 patients with clinically suspected ACL pathology from September 2021 to September 2023. Patients were collected by consecutive sampling. All patients underwent MRI with both conventional and DWI/ ADC mapping sequences and the findings on both sequences were assessed independently by two high experienced radiologists in musculoskeletal imaging and the findings were compared with clinical diagnoses, follow up and arthroscopic results when available. Results For partial tears, 10 cases (50%) were identified using arthroscopy/follow-up, while observer 1 identified 12 cases (60%) and observer 2 identified 9 cases (45%) using DWI/ADC. For complete tears, 10 cases (50%) were identified using arthroscopy/follow-up, while observer 1 identified 8 cases (40%) and observer 2 identified 11 cases (55%) using DWI/ADC. Conclusions DWI and ADC are useful tools for diagnosing tears, particularly complete tears, but that caution should be exercised when using these techniques to diagnose partial tears.