A retrospective study by Cecava et al [25] showed that knee radiography is a highly specific screening test for internal derangement in patients <40 years old with acute knee injury. In this patient population, knee effusion >10 mm on lateral radiograph should prompt consideration for the knee MRI examination, which can potentially decrease delayed diagnosis, improve patient outcomes, and decrease disability [25]. Magee et al [26] reported 96% sensitivity and 97% specificity of 3T MRI in the detection of meniscal tears in correlation with arthroscopy. However, a study by Van Dyck et al [21] showed similar high sensitivities and specificities of routine 3T and 1.5T MRI examinations in the evaluation of meniscal and ACL tears with arthroscopic correlation. Routine 3T MRI protocol did not significantly improve accuracy for evaluating the knee menisci and ACL compared with a similar 1.5T MRI protocol. MRI can diagnose the patterns and severity of bone marrow contusions that frequently have an association with the specific mechanisms of injury and can predict associated soft-tissue injuries [27,28]. In a study by Song et al [28], Acute Trauma to the Knee in the setting of the acute noncontact ACL injury, both the presence and the severity of lateral bone contusions were associated with high-grade pivot-shift, concomitant lateral meniscal lesions as well as anterolateral ligament abnormality. Klengel et al [29] found that the apparent diffusion coefficient maps are more sensitive than corresponding proton density-weighted fat-saturated turbo spin-echo MRI sequences for detection of bone marrow lesions after knee trauma and allowed detection of significantly more and larger bone marrow lesions. Additionally, apparent diffusion coefficient map evaluation improved diagnostic performance in regions with insufficient spectral fat saturation, such as the patella.
Acute Trauma to the Knee. A retrospective study by Cecava et al [25] showed that knee radiography is a highly specific screening test for internal derangement in patients <40 years old with acute knee injury. In this patient population, knee effusion >10 mm on lateral radiograph should prompt consideration for the knee MRI examination, which can potentially decrease delayed diagnosis, improve patient outcomes, and decrease disability [25]. Magee et al [26] reported 96% sensitivity and 97% specificity of 3T MRI in the detection of meniscal tears in correlation with arthroscopy. However, a study by Van Dyck et al [21] showed similar high sensitivities and specificities of routine 3T and 1.5T MRI examinations in the evaluation of meniscal and ACL tears with arthroscopic correlation. Routine 3T MRI protocol did not significantly improve accuracy for evaluating the knee menisci and ACL compared with a similar 1.5T MRI protocol. MRI can diagnose the patterns and severity of bone marrow contusions that frequently have an association with the specific mechanisms of injury and can predict associated soft-tissue injuries [27,28]. In a study by Song et al [28], Acute Trauma to the Knee in the setting of the acute noncontact ACL injury, both the presence and the severity of lateral bone contusions were associated with high-grade pivot-shift, concomitant lateral meniscal lesions as well as anterolateral ligament abnormality. Klengel et al [29] found that the apparent diffusion coefficient maps are more sensitive than corresponding proton density-weighted fat-saturated turbo spin-echo MRI sequences for detection of bone marrow lesions after knee trauma and allowed detection of significantly more and larger bone marrow lesions. Additionally, apparent diffusion coefficient map evaluation improved diagnostic performance in regions with insufficient spectral fat saturation, such as the patella.