MULTIPLANAR IMAGING IN THE PREOPERATIVE ASSESSMENT OF METALLIC INTRAOCULAR FOREIGN-BODIES - HELICAL COMPUTED-TOMOGRAPHY VERSUS CONVENTIONALCOMPUTED-TOMOGRAPHY

Objective: This study aimed to compare the effectiveness of helical co mputed tomography (CT) versus conventional CT in the preoperative asse ssment of metallic intraocular foreign bodies on axial, coronal, and m ultiplanar reconstruction images in clinical routine. Design: Prospect ive comparative trial, alternate assignment of consecutive patients. P articipants: Eighteen patients with penetrating eye injuries and suspe cted metallic intraocular foreign bodies were studied. Intervention: A lternate patients were assigned to undergo either helical CT or conven tional CT in the axial plane, Both the helical and the conventional da ta were transferred to a workstation, and reconstructions in the coron al and sagittal planes were performed. Additional direct coronal scann ing was performed only when necessary for preoperative assessment. Mai n Outcome Measures: The quality of the directly obtained axial and cor onal, as well as the reconstructed coronal and sagittal images, was as sessed for each imaging method based on the ability to detect and accu rately localize foreign bodies. The size of the foreign bodies was mea sured and compared to the actual diameter. Total examination time and radiation dose delivered to the lens were measured for each imaging me thod. Results: All foreign bodies were detected by each scanning metho d on the axial, the coronal, and on the reconstructed planes. The qual ity of the axial images was similar for helical and conventional CT. T he helical technique provided high-quality reconstructed images compar able in quality to the directly obtained coronal planes in conventiona l CT. Reconstructions by conventional technique were not useful for pr eoperative assessment. The examination time for the total orbital volu me was 18 seconds for helical CT examinations and 52 seconds for conve ntional CT examinations. Radiation dose delivered to the lens for the complete examination was 35 mGy for helical CT axial scanning, 56 mGy for conventional CT axial scanning, and 63 mGy for conventional CT cor onal scanning. Conclusions: Helical CT multiplanar imaging offers seve ral significant advantages for the preoperative assessment of metallic intraocular foreign bodies compared to the conventional CT technique in clinical practice, including short examination time, reduced motion artifacts, reduced radiation exposure, and the ability to obtain diag nostically useful coronal and sagittal reconstruction images without t he need for additional scanning.