Experimental study of artificially induced intramuscular gossypiboma in rabbits: correlation of sequential MRI findings with pathologic findings.

Abstract

The purpose of this study was to evaluate the sequential MRI findings of intramuscular gossypiboma and to correlate them with the pathologic findings in rabbits. Sterile gauze was packed in the hamstring muscles of 12 rabbits, and sequential MR images were obtained 1, 2, and 4 weeks and 2, 6, and 12 months after gauze insertion. Two rabbits were sacrificed at each time point. Their pathologic findings were compared with the MRI findings on each date. At the acute stage, the gossypibomas appeared as areas of heterogeneous low signal intensity on T2-weighted MR images with inflammatory change around the gossypiboma. In the subacute stage, the gossypibomas appeared as areas of peripheral low and central high signal intensity with wavy stripes of low signal intensity on T2-weighted images. On contrast-enhanced fat-suppressed T1-weighted images, the peripheral enhancement of the masses advanced toward the center of the mass as the fibrocollagenization between the gauze bundles progressed centrally. In the chronic stage, on contrast-enhanced fat-suppressed T1-weighted images, central advancement of the peripheral enhancement occurred according to the maturation of the fibrocollagenization. Calcifications around individual gauze fibers were observed 6-12 months after gauze insertion. On sequential contrast-enhanced fat-suppressed T1-weighted images of rabbits, intramuscular gossypiboma exhibited a chronologic centripetal enhancement pattern for 1 year mainly owing to concentric progression of fibrocollagenization between gauze bundles toward the center of the mass.