Some investigators have reported that FDG-PET is more accurate than bone scintigraphy and labeled leukocyte and marrow imaging, whereas other investigators have reported the opposite results [61,82,87,88,95,96]. Fluoride PET/CT Skull Base To Mid-Thigh Based on the available data, fluoride PET/CT does not appear to offer any advantages over FDG-PET/CT or 3- phase bone scintigraphy for diagnosing periprosthetic hip infection [97-100]. Image-Guided Aspiration Hip Although both false-positive and false-negative results may occur, joint aspiration with synovial fluid analysis remains probably the most useful test for confirming the presence or absence of infection and identifying the causative organism [101]. A meta-analysis by Carli et al [102] yielded a mean sensitivity of 68.6% and a specificity of 96.4% for joint aspiration culture. Hip aspiration can be performed using fluoroscopic, US, or CT guidance or without image guidance [103-105]. Contrast injection has been described for CT arthrography following joint aspiration [106]. Specific tests of retrieved synovial fluid such as alpha-defensin and polymerase chain reaction for bacteria and leukocyte esterase are beyond the scope of this review [107]. MRI Hip MRI can demonstrate soft tissue and bone features associated with periprosthetic infection, including inflammatory synovitis that may have a lamellated appearance [108], soft tissue edema, lymphadenopathy, fluid collections, bone marrow edema, and periosteal reaction [72,109-112]. IV contrast can be used to differentiate phlegmon from abscess and to define sinus tracts and communicating fluid collections [72]. However, IV contrast is generally not necessary to make the diagnosis of infection [72]. Evaluation of 19 patients suspected of having infection showed noncontrast MRI to be highly reproducible in the detection, localization, quantification, and characterization of fluid collections [113].
Imaging after Total Hip Arthroplasty PCAs. Some investigators have reported that FDG-PET is more accurate than bone scintigraphy and labeled leukocyte and marrow imaging, whereas other investigators have reported the opposite results [61,82,87,88,95,96]. Fluoride PET/CT Skull Base To Mid-Thigh Based on the available data, fluoride PET/CT does not appear to offer any advantages over FDG-PET/CT or 3- phase bone scintigraphy for diagnosing periprosthetic hip infection [97-100]. Image-Guided Aspiration Hip Although both false-positive and false-negative results may occur, joint aspiration with synovial fluid analysis remains probably the most useful test for confirming the presence or absence of infection and identifying the causative organism [101]. A meta-analysis by Carli et al [102] yielded a mean sensitivity of 68.6% and a specificity of 96.4% for joint aspiration culture. Hip aspiration can be performed using fluoroscopic, US, or CT guidance or without image guidance [103-105]. Contrast injection has been described for CT arthrography following joint aspiration [106]. Specific tests of retrieved synovial fluid such as alpha-defensin and polymerase chain reaction for bacteria and leukocyte esterase are beyond the scope of this review [107]. MRI Hip MRI can demonstrate soft tissue and bone features associated with periprosthetic infection, including inflammatory synovitis that may have a lamellated appearance [108], soft tissue edema, lymphadenopathy, fluid collections, bone marrow edema, and periosteal reaction [72,109-112]. IV contrast can be used to differentiate phlegmon from abscess and to define sinus tracts and communicating fluid collections [72]. However, IV contrast is generally not necessary to make the diagnosis of infection [72]. Evaluation of 19 patients suspected of having infection showed noncontrast MRI to be highly reproducible in the detection, localization, quantification, and characterization of fluid collections [113].