Radiology in NSTIs

 Q: Due to gas formation in tissues which is the best diagnostic modality in necrotizing soft tissue infections (NSTIs)? (select one)

A) CT scan

B) MRI

C) Ultrasound

Answer: A

Though MRI and ultrasound can be performed in NSTIs, they are not as reliable to delineate surgical demarcation as a CT scan. MRI is oversensitive and cannot distinguish well between necrotizing cellulitis and deeper infection. Ultrasound can be used due to the presence of gas but so far evidence for its use is not very supportive. 

CT scan can reliably show gas presence in soft tissues, collection of fluid, heterogeneity of tissue enhancement, and inflammatory changes.

#surgical-critical-care

#radiology

References:

1. Zacharias N, Velmahos GC, Salama A, et al. Diagnosis of necrotizing soft tissue infections by computed tomography. Arch Surg 2010; 145:452. 

2. Schmid MR, Kossmann T, Duewell S. Differentiation of necrotizing fasciitis and cellulitis using MR imaging. AJR Am J Roentgenol 1998; 170:615.