Fig. 3

a Axial T1 WI and b axial T2 WI showing a well-defined thick-walled multi-locular cystic lesion displaying low T1 and high T2 signal intensities. c DWI and d ADC map showing restricted diffusion, with the predominant bright areas on DWI corresponding to dark areas on the ADC map (ADC mean = 0.82 × 10⁻³ mm²/s). Ultrasound-guided aspiration cytology revealed pus cells (empyema)