Ultrasonography Detection of Radiolucent Foreign Bodies in Soft Tissue Compared to Computed Tomography Scan

Abstract

Thirty-one patients with suspected radiolucent foreign bodies (wooden splinters) in soft tissues of extremities were investigated by plain radiography, computed tomography (CT) scan and ultrasonography to the area suspected clinically. Ultrasonography detected and localized radiolucent foreign bodies in 18 of the 31 patients, while only 14 were seen on CT scan. Following surgical exploration, the presence of foreign bodies was confirmed in 20 patients; thus, the accuracy of ultrasonography was 90% while that of CT scan was 70%. The size of foreign body, the presence of infection or the delay in diagnosis had no effect on results. Ultrasonography is clearly a reliable method of detecting radiolucent foreign bodies in soft tissues of extremities. Ann Saudi Med 1995;15 (2) There are various modalities to detect and localize radiolucent foreign bodies in soft tissues, but none of these investigations independently could be considered entirely conclusive.1,2 This paper evaluates the role of ultrasonography to detect and localize nonradiopaque foreign bodies in soft tissues and compare its efficacies over other methods of assessment including clinical, radiographic and CT examinations. Patients and MethodsThirty-one consecutive patients complaining of suspected embedded thorns or wooden splinters in soft tissues of the limbs were investigated. There were 23 males and 18 females. The ages ranged between five years and 41 years (mean 22.8 y). The site of the thorn prick was in the foot in 20 patients, in the hand in three, in the thigh in three, in the forearm in three and in the legs in two patients.The following protocol was followed to detect and localize foreign bodies in the soft tissues before surgical exploration: All patients were clinically examined and the area in question was marked by a radiopaque marker and plain radiographic pictures were taken in two views. Ultrasonography was performed by a radiologist using 5 mHz, RT 3000 linear array transducer in water bath in two planes. Fresh wooden objects show up bright sonographically and cast a distal shadow. If these objects decompose, then secondary signs such as edema may accentuate the object by providing a hyperechoic halo. CT scan of the area was also carried out using 2 mm cuts which clearly distinguished the embedded thorn from the adjacent tissue. Following these investigations, the area in question was explored and the efficacy of each investigation was evaluated in relation to its accuracy in detecting and localizing the foreign bodies irrespective of their size and depth, the time factor and the presence of infection.

Diagnostic Accuracy of Ultrasonography in Retained Soft Tissue Foreign Bodies: A Systematic Review and Meta-analysis

“…After our complete review of these articles and their reference sections and our limited reviews of other databases, we included 17 articles in this metaanalysis (Table 1). All 17 studies [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] reported data for calculation of sensitivity; however, only 13 [23][24][25][26][27][28][29][30][31][32][33][34]36,37 reported data for calculation of specificity.…”

“…Including this study, three studies 26,34,36 reported on only lowerextremity injuries, while three 21,24,29 reported on only upper extremity injuries. Two studies 23,34 reported on exclusively wooden foreign bodies, and two 31,33 examined radiolucent or nonradiopaque foreign bodies.…”

Comparative Sensitivity Assessment of Cone Beam Computed Tomography and Digital Radiography for detecting Foreign Bodies

“…In a study by Al-Zahrani et al in a study on 31 patients with suspected radiolucent wood particles in soft tissues, used CT and ultrasound for foreign body detection and results demonstrated that size of foreign body does not influence their diagnosis. 10…”

Avaliação de métodos radiológicos na detecção de corpo estranho de madeira em modelo animal

“…Na literatura, alguns estudos sugerem que a US seja o melhor método para diagnosticar CE 6,13 . Com utilização de cadáveres, CEs de madeira, plástico, metal e vidro foram avaliados, indistintamente, e a sensibilidade e a especificidade variaram de 89% a 94% e de 94% a 99% 14,15 , respectivamente.…”

“…Em um relato com 39 pacientes, a TC sugeriu a presença de 14 CEs, enquanto a exploração cirúrgica revelou 20 CEs, resultando em uma sensibilidade de 70%. Contudo, neste mesmo estudo, a US foi superior, com uma sensibilidade de 90% 13 . Em nossa pesquisa, a madeira se apresentou como uma imagem hiperdensa à TC (Figura 1C) e, dentre todas as modalidades de exame, este apresentou os mais altos percentuais de sensibilidade e acurácia.…”