Supplementary Material for: Value of diagnosis and management for skin lesions by integration of high-frequency ultrasound in daily practices: a prospective study

Objectives: To identify whether high-frequency ultrasound (HFUS) could correct the misdiagnosis, confirm equivocal skin lesions, and improve the management after clinical examination. Methods: In this study, a total of 574 skin lesions from 552 patients were prospectively enrolled. The specific diagnosis and management decisions (treatment/excision, observation) determined by HFUS after clinical examination were recorded during the clinical practice. The area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the number needed to excise (NNE) before and after HFUS were also evaluated. The pathological results were conducted as golden standards to compare the performance. Results: Among the 574 skin lesions, 290 (50.5%) were malignancies and 284 (49.5%) were benign. The diagnostic accuracy was improved from 77.5% to 90.8% after the HFUS examination. There were 44 lesions wrongfully diagnosed by the initial clinical diagnosis, whereas 28 of 44 lesions (63.6%) were correctly identified by HFUS examination. Of 85 lesions categorized as equivocal skin lesions by clinical examination, 65 (76.5%) were diagnosed correctly after HFUS. Lesion management changed in 72 of 574 (12.5%) after HFUS. Among these lesions, HFUS saved 22 unnecessary excisions and prompted the treatment of 30 malignancies that would be observed based on clinical examination alone. Additionally, the NNE was reduced by 15.4% (NNE, 0.828) after HFUS and 4.6% (NNE, 0.933) before HFUS. Conclusions: HFUS could be a valuable tool in diagnosing equivocal skin lesions, identifying skin cancers missed by clinical examination, and reducing unnecessary excision of benign lesions while improving NNE.