Forehead augmentation is performed for improving the upper facial contour. A variety of alloplastic implants have been used for this purpose, including polytetrafluoroethylene and silicone. Often, silicone implants have corrugated edges and central perforations in order to optimize fixation and prevent capsular contraction. Fillers, such as calcium hydroxyapatite, also have a role in forehead augmentation. These materials can be inserted in the midline (Figs. 1.2 and 1.3), lateral brow (Fig. 1.4), or both. Botox is another minimally invasive option for reducing lines and wrinkles.

Cheek augmentation consists of expanding the malar region, submalar region, or a combination of these, often bilaterally. The procedure is performed for soft tissue enhancement or simply for correcting a deficient or atrophic face, including HIV lipoatrophy. A wide variety of materials have been used for these purposes, including coral implants (Fig. 1.5), silicone rubber implants (Fig. 1.6), injectable silicone (Fig. 1.7), injectable calcium hydroxyapatite (Fig. 1.8), polytetrafluoroethylene strips (Fig. 1.9), hyaluronic acid (Fig. 1.10), collagen (Fig. 1.11), alkyl-imide gel polymer (Fig. 1.12), and combination of materials (Fig. 1.13).

Seromas can be present and appear as simple fluid collections surrounding the implants (Fig. 1.14). Seromas typically resolve spontaneously, unless there is superimposed infection. In such cases, the patient may present with fever and purulent drainage. On imaging, stranding of the subcutaneous fat overlying the implant is often evident (Fig. 1.15). Additional manifestations of implant-associated infections include osteomyelitis and draining sinuses (Fig. 1.16). Other complications depend on the type of material used. In particular, liquid silicone can induce extensive inflammation, which appears as stranding or high T2 signal in the subcutaneous tissues (Fig. 1.17). Furthermore, injected nonmedical-grade silicone has a particular propensity to cause scars and granulomas. These complications can develop many years after injection of the filler. Hypertrophic scars can appear as bands of soft tissue within the subcutaneous fat on CT (Fig. 1.18). Granulomas often appear as subcentimeter rounded or oval foci of variable attenuation on CT (Fig. 1.19). Silicone foreign body granulomas can contain microcalcifications or form eggshell calcifications. Implants, such as silicone rubber, can occasionally erode through the bone (Fig. 1.20) and potentially result in sinusitis. Cheek implantation can sometimes induce heterotopic bone formation (Fig. 1.21). Bone grafts can resorb over time, thereby also diminishing cosmetic effect. Migration of fillers or implants can mimic mass lesions and impair vision (Fig. 1.22).