They found a sensitivity of 86% to 92% and a specificity of 85% to 87%, with almost perfect interobserver agreement, when using the appearance of lamellated hyperintense synovitis to classify infected versus noninfected TKA. Li [95] also reported a different lamellated and hyperintense appearance of the synovium in infected joints, which can be differentiated from frond- like and hypertrophied synovium associated with particle-induced synovitis and from homogeneous fluid-signal intensity effusion associated with a nonspecific synovitis. MRI with metal artifact reduction technique has also been shown to detect osteolysis that is not visible on radiographs [96,97]. Contrast may provide additional benefit in detecting extracapsular spread of infection and abscess formation when compared to noncontrast MRI. MRI Knee Without IV Contrast MRI may have a role in the workup of periprosthetic infection. Advances in metal artifact reduction may expand the potential role of MRI. Using metal reduction techniques, Potter and Foo found that infected synovium has hyperintense laminar appearance, distinct from the appearance of particle disease [22,93]. They noted that, in selected cases, MRI may be helpful in detecting extracapsular spread of infection and abscess formation. Plodkowski et al [94] examined 28 patients with proven infected TKAs and 28 controls with noninfected TKA. They found a sensitivity of 86% to 92% and a specificity of 85% to 87%, with almost perfect interobserver agreement, when using the appearance of lamellated hyperintense synovitis to classify infected versus noninfected TKA. Li et al [95] also reported a different lamellated and hyperintense appearance of the synovium in infected joints, which can be differentiated from frond-like and hypertrophied synovium associated with particle-induced synovitis and from homogeneous fluid-signal intensity effusion associated with a nonspecific synovitis.
Imaging After Total Knee Arthroplasty. They found a sensitivity of 86% to 92% and a specificity of 85% to 87%, with almost perfect interobserver agreement, when using the appearance of lamellated hyperintense synovitis to classify infected versus noninfected TKA. Li [95] also reported a different lamellated and hyperintense appearance of the synovium in infected joints, which can be differentiated from frond- like and hypertrophied synovium associated with particle-induced synovitis and from homogeneous fluid-signal intensity effusion associated with a nonspecific synovitis. MRI with metal artifact reduction technique has also been shown to detect osteolysis that is not visible on radiographs [96,97]. Contrast may provide additional benefit in detecting extracapsular spread of infection and abscess formation when compared to noncontrast MRI. MRI Knee Without IV Contrast MRI may have a role in the workup of periprosthetic infection. Advances in metal artifact reduction may expand the potential role of MRI. Using metal reduction techniques, Potter and Foo found that infected synovium has hyperintense laminar appearance, distinct from the appearance of particle disease [22,93]. They noted that, in selected cases, MRI may be helpful in detecting extracapsular spread of infection and abscess formation. Plodkowski et al [94] examined 28 patients with proven infected TKAs and 28 controls with noninfected TKA. They found a sensitivity of 86% to 92% and a specificity of 85% to 87%, with almost perfect interobserver agreement, when using the appearance of lamellated hyperintense synovitis to classify infected versus noninfected TKA. Li et al [95] also reported a different lamellated and hyperintense appearance of the synovium in infected joints, which can be differentiated from frond-like and hypertrophied synovium associated with particle-induced synovitis and from homogeneous fluid-signal intensity effusion associated with a nonspecific synovitis.