MRI Extremity Area of Interest In one study, a large field-of-view MRI was performed to encompass both lower extremities rather than the area of concern [38]. In patients who were later found to have osteomyelitis, 11% had contralateral extremity findings, including contralateral osteomyelitis, and 20% had ipsilateral septic arthritis. Among patients who did not have osteomyelitis, 20% had contralateral abnormalities; most common diagnoses included stress reaction, soft-tissue edema, myositis, sterile joint effusion, and leukemia. Osteomyelitis or Septic Arthritis-Child US Area of Interest US is a highly sensitive method of diagnosing hip joint effusion, and the absence of hip joint effusion virtually excludes septic arthritis; a false negative rate of 5% has been described, noted in patients with a shorter duration of symptoms (<1 day) [40,43,45-47]. US can reportedly detect hip effusions as small as 1 mL [44]. Hip US for the purpose of identifying joint effusion can be performed with high sensitivity and specificity [48]. In one study, nearly 80% of pediatric patients with hip septic arthritis required US imaging alone to guide their management [45]. US in evaluation of osteomyelitis is limited in its ability to assess the osseous structures but can identify abutting inflammatory changes affecting the soft tissues such as periosteal elevation and subperiosteal collections [40,49,50]. Although some studies have shown no significant difference in sensitivity and specificity in diagnosis of osteomyelitis or septic arthritis with or without the use of gadolinium-based contrast agents, contrast has been shown to improve detection of abscesses [32,33]. Decreased femoral head enhancement on early postcontrast imaging has been noted as a reliable feature of septic arthritis not seen in transient synovitis [34]. In addition, MRI has been shown to be useful in evaluating for concurrent musculoskeletal infection.
Osteomyelitis or Septic Arthritis Child Excluding Axial Skeleton PCAs. MRI Extremity Area of Interest In one study, a large field-of-view MRI was performed to encompass both lower extremities rather than the area of concern [38]. In patients who were later found to have osteomyelitis, 11% had contralateral extremity findings, including contralateral osteomyelitis, and 20% had ipsilateral septic arthritis. Among patients who did not have osteomyelitis, 20% had contralateral abnormalities; most common diagnoses included stress reaction, soft-tissue edema, myositis, sterile joint effusion, and leukemia. Osteomyelitis or Septic Arthritis-Child US Area of Interest US is a highly sensitive method of diagnosing hip joint effusion, and the absence of hip joint effusion virtually excludes septic arthritis; a false negative rate of 5% has been described, noted in patients with a shorter duration of symptoms (<1 day) [40,43,45-47]. US can reportedly detect hip effusions as small as 1 mL [44]. Hip US for the purpose of identifying joint effusion can be performed with high sensitivity and specificity [48]. In one study, nearly 80% of pediatric patients with hip septic arthritis required US imaging alone to guide their management [45]. US in evaluation of osteomyelitis is limited in its ability to assess the osseous structures but can identify abutting inflammatory changes affecting the soft tissues such as periosteal elevation and subperiosteal collections [40,49,50]. Although some studies have shown no significant difference in sensitivity and specificity in diagnosis of osteomyelitis or septic arthritis with or without the use of gadolinium-based contrast agents, contrast has been shown to improve detection of abscesses [32,33]. Decreased femoral head enhancement on early postcontrast imaging has been noted as a reliable feature of septic arthritis not seen in transient synovitis [34]. In addition, MRI has been shown to be useful in evaluating for concurrent musculoskeletal infection.