MAGNETIC-RESONANCE-IMAGING OF RETICULOENDOTHELIAL SYSTEM IN PATIENTS WITH IDIOPATHIC THROMBOCYTOPENIC PURPURA

Idiopathic thrombocytopenic purpura (ITP) is characterized by accelera ted platelet destruction in the reticulo-endothelial system (RES). We performed magnetic resonance imaging (MRI) to estimate the degree of a ctivated RES. MRI was performed with a Gyroscan S-15 (1.5 tesla) in 7 healthy volunteers and 22 patients with ITP. The 22 patients included 19 who were at initial diagnosis or were nonresponders to the therapy (non-DX group), and 3 who were responders. For the non-DX group, the T 1 relaxation time of the spleen was initially significantly shorter th an for healthy volunteers, but normalized after responding to be thera py. The initially shorter T1 values of the spleen for ITP patients cor related with a low platelet count (P < 0.05). This condition may indic ate foam cells or fatty components due to platelet destruction. There was no significant relationship between the sequestration in In-111-sc an and T1 values of the liver or spleen. However, MRI is a noninvasive method, and it may be a clinically useful tool in the evaluation of R ES in patients with ITP. (C) 1997 Wiley-Liss. Inc.