Also, US can evaluate for deep venous thrombosis, provide image guidance for fluid aspiration, use color Doppler, and assess for foreign bodies [52,59]. The US appearance of soft tissue gas is typically an echogenic region or foci along the superficial and/or deep fascia with some degree of incomplete posterior acoustic shadowing. The presence of gas causes the posterior acoustic shadowing, and the changes in echotexture does impede sound penetration which can limit visualization of deeper structures [57]. For NF, this may cause US to have a limited role for the evaluation of the deeper intermuscular fascia especially in larger body habitus patients [52,57]. The subcutaneous fat can be thickened and demonstrate overall increased echogenicity due to fat edema and inflammatory change. Also, the fat lobules can form a cobblestone appearance due to the thickening of subcutaneous fat septa [52,57,59,60]. Although these findings are not specific for NF and Suspected Osteomyelitis, Septic Arthritis can be seen in cellulitis or anasarca, finding irregular thickened fascia and abnormal fluid collections in deeper muscle fascia can help differentiate NF [52,60]. Consistent throughout the US literature is the importance of the detection of fluid accumulation and thickened deep intermuscular fascia for diagnosing NF [52,59-62]. The overall sensitivity of US for the diagnosis of NF varies from 42% to 88%, with a specificity of 70% to 94% [52,59,60]. These variations may be due to the amount of deep fascial thickening and fluid accumulation. There is limited evidence regarding the role of US in the diagnosis of NF [52,57,59,60]. Because CT and MRI are more sensitive modalities for visualizing fluid and fascial thickening, a negative US should not exclude the diagnosis of NF [61].
Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. Also, US can evaluate for deep venous thrombosis, provide image guidance for fluid aspiration, use color Doppler, and assess for foreign bodies [52,59]. The US appearance of soft tissue gas is typically an echogenic region or foci along the superficial and/or deep fascia with some degree of incomplete posterior acoustic shadowing. The presence of gas causes the posterior acoustic shadowing, and the changes in echotexture does impede sound penetration which can limit visualization of deeper structures [57]. For NF, this may cause US to have a limited role for the evaluation of the deeper intermuscular fascia especially in larger body habitus patients [52,57]. The subcutaneous fat can be thickened and demonstrate overall increased echogenicity due to fat edema and inflammatory change. Also, the fat lobules can form a cobblestone appearance due to the thickening of subcutaneous fat septa [52,57,59,60]. Although these findings are not specific for NF and Suspected Osteomyelitis, Septic Arthritis can be seen in cellulitis or anasarca, finding irregular thickened fascia and abnormal fluid collections in deeper muscle fascia can help differentiate NF [52,60]. Consistent throughout the US literature is the importance of the detection of fluid accumulation and thickened deep intermuscular fascia for diagnosing NF [52,59-62]. The overall sensitivity of US for the diagnosis of NF varies from 42% to 88%, with a specificity of 70% to 94% [52,59,60]. These variations may be due to the amount of deep fascial thickening and fluid accumulation. There is limited evidence regarding the role of US in the diagnosis of NF [52,57,59,60]. Because CT and MRI are more sensitive modalities for visualizing fluid and fascial thickening, a negative US should not exclude the diagnosis of NF [61].