Ultrasound elastography assessment of skin involvement in systemic sclerosis: lights and shadows

To assess skin elasticity in systemic sclerosis (SSc) by using a new imaging modality, ultrasound elastography (UE).

Our study included 18 consecutive patients with SSc and 15 healthy controls. Modified Rodnan skin score, physical examination, and assessment of organ involvement were performed. UE was carried out on the middle forearm and on the fingers of the dominant arm. The echo signals recorded in real time during freehand operations of probe compression and relaxation produced images representing tissue elasticity, consisting of translucent colored bands superimposed on the B-mode ultrasonographic images. The color scale varied within a large band spectrum from red, indicative of soft and highly elastic tissue, to blue, which denoted hard and barely elastic tissue.

On the forearm of all patients, UE showed a homogeneous blue area corresponding to the dermis visualized in a B-mode ultrasonographic image; in controls, a blue pattern was never detected and a predominance of green with sporadic areas of pale blue was observed. At sequential evaluations, UE of fingers produced inconstant and changeable colored areas.

The imaging pattern observed in the forearm of patients with SSc may represent the reduction of strain in the dermis due to loss of elasticity. The variable pattern obtained by finger evaluation demonstrated that UE can assess skin involvement in SSc only in those areas where the dermis is known to be thicker and where the bone hyperreflection is minimal. Further studies are needed to confirm our results and determine the validity of this new imaging modality.