Comparison of Radiographic, Ultrasound, and Magnetic Resonance Imaging for the Detection of Retained Stingray Barb: A Cadaveric Study

Abstract

Introduction-Stingray envenomations are a common marine animal injury for which it is important to identify and remove retained barbs to prevent secondary infection. The optimal imaging modality in stingray foreign body detection is not well characterized in the existing literature. In this study, we compared the accuracy of plain radiography, ultrasound, and magnetic resonance imaging (MRI) in detecting stingray barbs in the human foot and ankle.Methods-This cadaveric study included a 1:1 randomization to the presence or absence of barbs in 24 sample injuries of human cadaveric foot and ankle specimens. Physicians trained in emergency medicine and radiology performed ultrasound examinations on each specimen and interpreted the presence or absence of a barb. Participants also interpreted x-ray images in the same manner. MRI scans were separately interpreted by a musculoskeletal radiology attending. Data were analyzed using McNemar's test.Results-The 19 participants included 14 (74%) trained in emergency medicine and 5 (26%) trained in radiology. Forty-seven percent were residents, 42% faculty, and 11% fellows. X-ray was associated with the highest sensitivity of 94% for the identification of a retained barb, followed by MRI (83%) and ultrasound (70%). MRI was associated with the highest specificity of 100%, followed by x-ray (98%) and ultrasound (73%).Conclusions-Retained stingray barbs can lead to secondary infection after envenomation. In human cadaveric specimens, x-ray demonstrated the highest sensitivity, MRI demonstrated the highest specificity, and ultrasound demonstrated lower sensitivity and specificity.

Management of a stingray barb laceration and suspect envenomation in a dog

“…A recently published study compared radiographs, ultrasound, and MRI in detecting stingray barbs in 12 human cadaveric specimens. Analysis showed radiographs to have the highest sensitivity (94%) and MRI to have the highest specificity (100%) in identification of retained stingray barbs 11 . This is contrary to previous publications which have described MRI as gold standard 1,8,10 However, in this study, the stingray barbs were embedded into cadavers postmortem and therefore there was no soft tissue reaction surrounding the wound site which could enhance its visualisation, and therefore sensitivity, on MRI.…”

“…This is proposed due to their increased experience with musculoskeletal imaging with ultrasound, which emergency physicians do not routinely perfom. In both radiographs and MRI, there was no difference in accuracy between the radiology and emergency physicians 11 …”

“…Ultrasound had the lowest sensitivity (70%) and specificity (73%) for detecting retained barbs 11 . Ultrasound was also user dependent, with radiology physicians having higher accuracy (P = 0.03) than emergency physicians.…”

“…Ultrasound had the lowest sensitivity (70%) and specificity (73%) for detecting retained barbs. 11 Ultrasound was also user dependent, with radiology physicians having higher accuracy (P = 0.03) than emergency physicians. This is proposed due to their increased experience with musculoskeletal imaging with ultrasound, which emergency physicians do not routinely perfom.…”

A technical trick for extracting a stingray spine from hand: a case report

“…Magnetic resonance imaging or ultrasound can be used to detect radiolucent cartilage or sheath fragments. 2 Since these injuries are mostly seen in young people and ulcerated lesions can heal in 2-3 months, they cause morbidity and increase health costs and loss of work. 3 …”