Description of selected agents used for injection laryngoplasty
| Agents | Longevity | Imaging Findings |
|---|---|---|
| Hyaluronic acid gels (Restylane, Hylaform) | Temporary | Nearly fluid attenuation on CT; T1 hypointense and T2 hyperintense, similar to fluid on MRI; may display peripheral enhancement initially |
| Micronized cadaveric dermis (Cymetra) | Temporary | T1 and T2 hyperintense within the first year of injection |
| Bovine collagen preparations (Zyplast) | Temporary | Generally fluid attenuation on CT; T1 hypointense and T2 hyperintense, similar to fluid on MRI; may display peripheral enhancement initially |
| Calcium hydroxylapatite (Radiesse Voice) | Long-lasting | High attenuation on CT (280–700 HU); hypermetabolic on 18FDG-PET |
| Autologous fat | Long-lasting | Attenuation and signal characteristics of adipose tissue |
| Teflon | Permanent | Globular high attenuation on CT (200–400 HU range) |