Application of Ultrasound in the Identification of Foreign Bodies in Scalp Wound: A Cross-sectional Study

Introduction: Retained foreign bodies in wounds are among the most challenging problems in the emergency department (ED). They lead to wound infection and abscess, delayed healing, and wound scars.  Therefore, the present study aimed to determine the diagnostic value of ultrasound as an accessible and non-invasive modality in determining foreign bodies in scalp wounds. Methods: This cross-sectional analytical study was performed on 58 ED patients with scalp wounds who needed brain computed tomography (CT) scans and met the inclusion criteria. Firstly, wound exploration and irrigation of visible foreign bodies were performed. Thereafter, an ultrasound was carried out by an emergency medicine resident to detect the hidden foreign bodies (if exist) in the wound. Finally, a CT scan was administered (as the gold standard) to detect any remained foreign bodies. The foreign bodies were removed and the wound was sutured in the end. Sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, disease prevalence, positive predictive value, negative predictive value, and accuracy were assessed. Results: In total, the sensitivity, specificity, and accuracy of ultrasound were estimated as 91.43%, 100%, and 91.55%, respectively. Moreover, the positive predictive value and negative predictive value of ultrasound were reported as 100%and 14.29%, respectively. Conclusion:  As evidenced by the results of this study, ultrasound is a highly sensitive diagnostic method to detect foreign bodies in scalp wounds. In some cases, such as frontal lobe wounds, this modality may not detect all foreign bodies.