title: Superparamagnetic iron oxide-enhanced MR imaging for early and late radiation-induced hepatic injuries.
abstract: Superparamagnetic iron oxide (SPIO)-enhanced MRI was performed in twenty-one patients undergoing proton-beam radiotherapy for hepatocellular carcinomas. Patients were divided into two groups: early and late phase hepatic injuries. Each group was investigated 3 to 9 weeks and 4 to 65 months after the start of irradiation, respectively. T(1)-weighted, T(2)-weighted, and T(2)*-weighted images were obtained before and after SPIO administration. In all postcontrast sequences in the early phase, irradiated livers demonstrated relatively higher intensity than nonirradiated livers and the radiation-to-liver contrast-to-noise ratio (C/N) was improved. Postcontrast T(2)*-weighted images showed the highest C/N. In the late phase, the irradiated areas showed high intensity on T(2)-weighted images and low intensity on T(1)-weighted images without SPIO, while high intensity on T(1)-weighted images with SPIO. The C/N increased with SPIO in all sequences and postcontrast T(2)-weighted images showed the highest C/N in the late phase. SPIO-enhanced MRI is useful to evaluate this entity both in the early and late phase of clinical studies.
authors: Department of Radiology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Ibaraki, Japan. hir-yosh@md.tsukuba.ac.jp
authors: H
authors: H
authors: Yoshiokaa
authors: Y
authors: Y
authors: Itai
authors: Y
authors: Y
authors: Saida
authors: K
authors: K
authors: Mori
authors: H
authors: H
authors: Mori
authors: T
authors: T
authors: Okumura
mesh_terms: D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000532:radiotherapy; D003287:Contrast Media / Q000378:metabolism; D005260:Female; D005290:Ferric Compounds / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000293:injuries / Q000528:radiation effects*; D008113:Liver Neoplasms / Q000532:radiotherapy; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011832:Radiation Injuries / Q000473:pathology*
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; C000499:ferric oxide