Necrotizing soft-tissue infections (NSTIs) are serious infections caused by bacteria that can destroy tissues rapidly. These infections can lead to severe illness or even death if not diagnosed quickly. **Indocyanine Green (ICG)** is a special dye used for medical imaging, which helps in detecting these infections by highlighting blood flow in tissues.

This study uses a new imaging technique called **Dynamic Contrast-Enhanced Fluorescence Imaging (DCE-FI)** to better identify NSTIs. The research will be conducted across eight medical centers in the United States. The goal is to compare this new method with current tests to see which is more effective at diagnosing NSTIs. **Machine learning** will also be used in the study to help improve diagnosis accuracy.

• Study length: This is an observational study, meaning no new treatments will be given.
• Visits needed: Participants must visit a medical center for imaging and testing.
• Risks: If you are allergic to ICG or iodine, you cannot join the study.

Participants must be 18 or older and able to give informed consent. Pregnant or nursing women cannot participate. This study aims to improve NSTI detection, ultimately saving lives.