MDCT and superparamagnetic iron oxide (SPIO)-enhanced MR findings of intrapancreatic accessory spleen in seven patients

The aim of this study is to retrospectively evaluate intrapancreatic accessory spleen (IPAS) with mutidetector computed tomography (MDCT) and superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance imaging (MRI) with emphasis on the role of SPIO-MRI for the diagnosis of IPAS. Seven patients (four men and three women; mean age, 50.7 years) with IPAS underwent quadriphasic MDCT and SPIO-enhanced MRI. IPAS was diagnosed histopathologically (n=2) or by scintigraphy (n=5). Two radiologists evaluated CT and MRI in consensus for the location and size of each lesion and compared its attenuation on CT and signal intensity (SI) on MRI with those of the pancreas and spleen. For quantitative analysis, another radiologist calculated the mean lesional, pancreatic, and splenic attenuations or SIs on MDCT or MRI in each patient. All lesions were located in the pancreatic tail. The average lesion size was 1.5±0.5 cm. All IPASs except one appeared high-attenuating to the pancreas and were isoattenuating to the spleen on all dynamic CT phases. The IPASs were hypointense and hyperintense compared with the pancreas on unenhanced T1- and T2-weighted images, respectively, and their SI was similar to that of the spleen. On SPIO-enhanced, T2-weighted images, a similar degree of signal drop to that of the spleen was noted in all lesions. The results of the quantitative analysis were compatible with those of the subjective analysis. In most IPASs, the attenuation on CT and SI on MRI were identical to those of the spleen, and on SPIO-enhanced MRI, the degree of the signal drop in all lesions was similar to that of the spleen.