Figure 1.

Scans from contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) of suspected subdiaphragmatic abscess. In the transverse view (A) and coronal view (B) from CT: an emerging low-density cystic lesion in the subdiaphragmatic region (red arrow); T1-weighted image (T1WI): an area with low-signal intensity (red arrow) (C & D); the T2-weighted image (T2WI): slightly high signals in the lesion (red arrow) (E & F); follow-up CT scans: complete absorption of the lesion on the 28th day after drainage (red arrow) (G & H).

Figure 2.

Contrast-enhanced ultrasound images, and metagenomic next-generation sequencing (mNGS) results from suspected subdiaphragmatic abscess. Ultrasound examination on the day of admission: a cystic lesion in the subdiaphragmatic region (red arrow) (A); the lesion (indicated by the white arrow) did not exhibit enhancement after the injection of SonoVue (B); subsequent contrast-enhanced ultrasound examinations on the 3rd (C & D) and 6th (E) days after the drainage procedure: effective drainage of the abscess, with no signs of residual or recurrent abscess (red and white arrows); abundance of Cutibacterium modestum and other microorganisms by mNGS in the subdiaphragmatic abscess specimen and control (F). C. modestum: Cutibacterium modestum; C. acnes: Cutibacterium acnes; P. aeruginosa: Pseudomonas aeruginosa; K. pneumoniae: Klebsiella pneumoniae; S. dysgalactiae: Streptococcus dysgalactiae; M. doricum: Mycobacterium doricum; E. coli: Escherichia coli; S. maltophilia: Stenotrophomonas maltophilia; HBV: hepatitis B virus; TTV: Torque teno virus.