MR T1ρ and T2 of meniscus after acute anterior cruciate ligament injuries

Abstract

Objective To evaluate differences in meniscal T1ρ and T2 quantification in patients with acute anterior cruciate ligament (ACL) injuries and to determine correlations of these differences with MR morphological grading and patient-reported outcomes. Design Bilateral knees of 52 patients with acute ACL injury and 20 healthy controls were scanned using 3T MRI T1ρ and T2 mapping in this prospective study. Quantitative analysis of the meniscus was performed in anterior and posterior horns of the lateral and medial menisci. Morphological meniscal damage was assessed using modified whole-organ MRI scores (WORMS). Measurements were compared between injured, uninjured contralateral, and control knees using a mixed-effects regression model. Correlations between meniscal T1ρ/T2, WORMS and Knee Injury and Osteoarthritis Outcome Scores (KOOS) were examined using partial correlation analysis. Results Mean meniscal T1ρ and T2 values were significantly higher in ACL-injured knees compared to control and contralateral knees. Menisci of ACL-injured knees without tears, including those limited to modified meniscal WORMS grade 0, also had significantly higher T1ρ and T2 values compared to menisci of uninjured knees. Within ACL-injured knees, T1ρ and T2 values showed significant positive associations with meniscal WORMS and significant negative associations with KOOS. Conclusion Acute ACL injuries are associated with significantly increased meniscal T1ρ and T2 values in both patients with and without meniscal lesions or tears, suggesting quantitative MRI provides more sensitive measures of meniscal differences compared to traditional morphological MRI sequences. Correlation between meniscal T1ρ/T2 and KOOS suggest that quantitative MRI is reflective of the extent of patients’ clinical symptoms.

Clinical Utility of Advanced Imaging of the Knee

“…2). 15,38 Wang et al 38 reported significantly higher T 1 ρ and T 2 values in the meniscus, especially the posterior horn of the lateral meniscus, after ACL injury, which also correlated with worsening patient symptoms and knee function. In a longitudinal analysis of patients after ACL injuries, Knox et al 39 reported persistent abnormalities of the meniscus T 1 ρ and T 2 signal in the posterior horn of the medial meniscus.…”

“…37 Given the similarities to articular cartilage, T 1 ρ and T 2 mapping allow for detailed evaluation of the meniscus. 38,39 T 2 * has been shown to be significantly longer in degenerative menisci relative to normal meniscal tissue. Intrasubstance degeneration of the meniscus may also be evaluated with dGEMRIC, given its ability to reflect the proteoglycan content of the tissue.…”

Functional knee assessment with advanced imaging

“…In addition to cartilage, Wang et al also found elevation of T 1ρ and T 2 in the menisci of ACL-injured knees (Fig. 3) [59]. While these measurements themselves may not be considered Bfunctional^in the traditional biomechanical sense, this may provide an alternative to estimate joint laxity and the its proceding consequences.…”

Advanced Imaging in Osteoarthritis

“…107 Recently, UTE T2* and T1ρ have been used to analyze deep zones of the cartilage where non-UTE imaging may not be sensitive enough. UTE T2* is able to measure deep layers of cartilage while T2 cannot.…”