Splenic implants: evaluation with radionuclide methods

Ultrasound and Doppler features of accessory spleens and splenic grafts

16 splenic grafts and 24 accessory spleens were evaluated with ultrasound, colour Doppler and power Doppler imaging, in order to compare the features of splenic grafts and accessory spleens. 12 splenic grafts (11 surgically implanted, 1 islet of splenosis) were detected in eight patients following splenectomy 6-12 months previously. Four of the surgically implanted splenic grafts were found in three patients following splenectomy 16-18 days previously. 21 accessory spleens were incidentally detected in 20 subjects who had not been operated upon, whereas three enlarged accessory spleens were found in 10 patients who underwent splenectomy 6-12 months previously. The size, shape, rim features, echogenicity, acoustic enhancement and vascularization of the splenic grafts and accessory spleens were evaluated. The splenic grafts were oval with lobulated margins, an inhomogeneous pattern in 36% and acoustic enhancement in 64%. Multiple feeding vessels arising from the surrounding tissue entered the periphery of 10 splenic grafts in the eight patients operated on 6-12 months previously, whereas no vascular signals were detected in the four splenic grafts of the three patients operated on 16-18 days ago. Accessory spleens were round with smooth echogenic margins and a vascular hilum arising from the splenic vessels. In conclusion colour Doppler and power Doppler allow differentiation between accessory spleens and splenic grafts basing on their shape and vascular supply.

SPECT demonstration of splenosis

Splenosis is defined as the heterotopic autotransplantation of splenic tissue. The main cause of splenosis is splenic rupture following abdominal trauma, in which fragments of splenic tissue are seeded throughout the peritoneal cavity. Demonstration of splenosis by scintigraphy or CT imaging has been reported, but there is no previous report of simultaneous demonstration by SPECT and CT imaging. Autotransplantation of splenic tissue in the abdominal cavity forms a solid tumor-like image on CT and is difficult to differentiate from other abdominal masses. In such cases, SPECT demonstration of splenosis is very important for identification of its exact site. A case report of splenosis is presented, in which simultaneous demonstration by SPECT and CT was performed. This was confirmed at laparotomy for gastrectomy.