Shear wave elastography-derived scoring system: application in the detection, subdivision and evaluation of systemic sclerosis.

OBJECTIVES:To locate the most valuable sites for shear wave elastography (SWE) evaluation and to develop a clinically applicable scoring system based on SWE for systemic sclerosis (SSc) and to verify the accuracy for detection and subdivision and the correlation by modified Rodnan total skin score (mRTSS). METHODS:SSc patients with limited cutaneous SSc (lcSSc) and diffuse cutaneous SSc (dcSSc) and symptomatic other rheumatic diseases (ORD) patients were included in this cross-sectional study. We assessed the skin stiffness at forehead, chest, abdomen, and bilateral fingers, hands, forearm, arms, thighs, legs, and feet, by palpation and SWE. Logistic regression was used to screen the most valuable sites for detection of SSc and subdivision of lcSSc and dcSSc, on which a scoring system was developed and verified. RESULTS:A total of 49 lcSSc, 51 dcSSc, and 36 ORD patients were included. The SWE-derived scoring system, including finger, hand, foot, arm, chest, and abdomen, reached a sensitivity and specificity of 80.0% and 94.4%, respectively, for diagnosing SSc at the cut-off value >24. The scoring system, including arm, chest, and abdomen, reached a sensitivity of 72.5% and specificity of 98.0% for subdividing dcSSc at the cut-off value >11. The kappa coefficient between the SWE-derived diagnosis and clinical diagnosis was 0.636 (P<0.001). The SWE-derived total scores of six sites had a strong correlation with mRTSS (r=0.757, p<0.001). CONCLUSIONS:The SWE-derived scoring system can be valuable in detection and evaluation of SSc in clinical application.