title: Normalized spleen/liver ratios on 111In-labelled platelet scintigraphy to predict the outcome of partial splenic embolization in patients with idiopathic thrombocytopenic purpura.
abstract: In this study, we examined the use of 111In-labelled platelet imaging to predict the outcome of partial splenic embolization (PSE) in patients with idiopathic thrombocytopenic purpura (ITP). Thirty-eight patients with a clinical diagnosis of ITP underwent 111In-labelled platelet scintigraphy. Twenty-four patients with intractable ITP underwent PSE after 111In-labelled platelet scintigraphy. The conventional spleen/liver ratio at 1 h and 192 h and the normalized spleen/liver ratio [(spleen uptake at 192 h/liver uptake at 192 h)/(spleen uptake at 1 h/liver uptake at 1 h)] were compared between responders and non-responders to PSE. Patients with ITP showed a significant reduction in platelet counts, increased platelet associated IgG, decreased platelet survival, and an increased conventional spleen/liver ratio at 192 h. No significant difference was found between patients who had and who had not undergone previous medical treatment. A significant difference was observed in the mean conventional spleen/liver ratio at 192 h between responders and non-responders, but there was substantial overlap among individuals. The mean normalized spleen/liver ratio was significantly higher in responders than non-responders; there was less overlap between the two groups with the normalized spleen/liver ratio than the conventional spleen/liver ratio. The therapeutic outcome of PSE is predicted more accurately using a normalized spleen/liver uptake ratio of 111In-labelled platelets in patients with idiopathic thrombocytopenic purpura than a conventional splenic/hepatic uptake ratio on delayed images.
authors.affiliation: Department of Radiology, Chiba University School of Medicine, Japan. uchiday@ho.chiba-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Uchida
authors.forename: S
authors.initials: S
authors.lastname: Minoshima
authors.forename: M
authors.initials: M
authors.lastname: Miyazaki
authors.forename: J
authors.initials: J
authors.lastname: Kuyama
authors.forename: H
authors.initials: H
authors.lastname: Kitahara
authors.forename: H
authors.initials: H
authors.lastname: Ito
mesh_terms: D000328:Adult; D001792:Blood Platelets / Q000378:metabolism; D004621:Embolization, Therapeutic; D005260:Female; D006801:Humans; D007205:Indium Radioisotopes / Q000493:pharmacokinetics*; D008099:Liver / Q000378:metabolism*; D008297:Male; D010976:Platelet Count; D011446:Prospective Studies; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000000981:diagnostic imaging / Q000378:metabolism*; D011877:Radionuclide Imaging; D013154:Spleen / Q000378:metabolism*
chemical_list: D007205:Indium Radioisotopes