Fig. 1From: Coinfection of Clostridium perfringens and Escherichia coli in gas-producing perianal abscess diagnosed by 16S rDNA sequencing: a case reportUltrasound and CT images of the buttocks showing gas-producing perianal infection. A Anechoic area (1.9 cm × 1.1 cm) detected by ultrasound with a thickened subcutaneous layer. B Multiple liquid and gas zones (red arrows) and gas–liquid planes detected in the muscle spaces in the left hip on the transaxial CT planeBack to article page