Composition of intraocular foreign bodies: experimental study of ultrasonographic presentation

Abstract

Purpose: To investigate the reliability of ultrasound in determining the size and identify the sonographic features and artifacts generated by intraocular foreign bodies of different materials. Methods: Experimental study using 36 enucleated porcine eyes. Fragments of nine different compositions (wood, glass, plastic, cardboard, iron, aluminum, lead, powder and concrete) and similar dimensions (4 mm) were implanted via scleral incision into the vitreous cavity of 36 porcine eyes, four eyes were used for each material. Ultrasound examination was performed in all eyes using the contact technique, conductive gel and 10MHz transducer (EZScan, Sonomed). Results: Considering the material fragments of gunpowder, lead, concrete, alu minum, wood and glass, the size determined by ultrasound was considered statistically similar to the actual size. The material iron presented ultrasoundde termined dimension statistically smaller than its actual size. Cardboard and plastic materials showed ultrasounddetermined measurements far greater than the actual. All fragments of intraocular foreign bodies demonstrated hyperreflective interfaces, irrespective of their composition. Whereas the artifacts generated by different materials, it was found that the materials iron, aluminum and lead showed reverberation of great extent. The material wood showed no reverberation. The length of the reverberation artifact for the materials iron, glass, aluminum and cardboard was lower when compared to other materials. All materials presented posterior shadowing artifact, with the exception of aluminum. Conclusion: Ultrasonography was considered a reliable technique to determine the size of intraocular foreign bodies in pigs, with little influence caused by its composition. Ultrasound artifacts generated were considered materialdependent and can assist the examiner to identify the nature of a foreign body of unknown etiology. Ultrasonography aided the surgeon to identify, locate and measure the intraocular foreign body, directing appropriate surgical planning.

Validation of an Algorithm for Nonmetallic Intraocular Foreign Bodies' Composition Identification Based on Computed Tomography and Magnetic Resonance Imaging

“…17,24 Ultrasonography may identify nonmetallic IOFBs, but it does not allow recognition of IOFB composition and has been shown to be unable to discern between metallic and nonmetallic IOFBs. 25 It may also be hazardous to perform in patients with penetrating or perforating ocular injuries. 9 Our previous study has demonstrated that MRI is superior to CT in identifying nonmetallic IOFBs.…”

Ultrasonography for foreign bodies in the soft tissue

“…Some cases have been reported of the use of US for the removal of foreign bodies from the eyelid [9,10,12]. US has also been used for the removal of fish bones from tongues and esophagi [13][14][15], foreign bodies from children's extremities [16,17], and for radiolucent foreign bodies in children's stomachs [18].…”

An artificial pneumoperitoneum created by injection of oxygen may prevent acute mountain sickness

“…However, knowledge regarding the use of US for soft tissue foreign bodies is limited. Mainly, case reports, case series, and experimental studies have been reported [8][9][10].…”

“…Removal of these foreign bodies is sometimes difficult. Some cases have been reported of the use of US for the removal of foreign bodies from the eyelid [9,10,12]. Ultrasonography has also been used for the removal of fish bones from tongues and esophagi [8,13,14], foreign bodies from children's extremities [15,16], and for radiolucent foreign bodies in children's stomachs [17].…”

“…When the needle enters the peritoneal cavity, the trocar is withdrawn to make sure that no blood is present and that the intestines have not been contacted. First, 5 mL of saline are injected into the peritoneal cavity, and then oxygen is injected slowly ensuring that the pressure of peritoneal cavity remains less than 14 mm Hg [10].…”