title: R2* Map by IDEAL IQ for Acute Cerebral Infarction: Compared with Susceptibility Vessel Sign on T2*-Weighted Imaging.
abstract: BACKGROUND
  To evaluate the detectability of arterial acute thrombus on R2* map by iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) IQ compared with T2*-weighted imaging (T2*WI).
  
  
  METHODS
  Twenty-six patients with acute cerebral infarction who underwent R2* map and T2*WI were reviewed. We performed visual assessment of each sequence regarding the visibility of susceptibility effect reflecting acute thrombus and quantitative evaluation of the thrombus on R2* map.
  
  
  RESULTS
  Both R2* map and T2*WI showed susceptibility effect reflecting acute thrombi at the occluded site of magnetic resonance angiography (MRA) in 9 patients. R2* map revealed positive while T2*WI showed equivocal findings in 3 patients due to the surrounding vessel signal intensity. Acute thrombus at distal internal carotid artery (ICA) on R2* map was more clearly detected than that on T2*WI without any apparent susceptibility artifact from the skull base in 4 patients. Most of cardiogenic embolic infarction (CEI) and artery-to-artery embolic infarction (A-to-A) demonstrated positive and most of atherothrombotic infarction (ATI) revealed negative findings on R2* map, although quantitative R2* values of thrombi did not show significant differences between CEI (136.6 /msec) and A-to-A (189.9 /msec) (P= 0.332).
  
  
  CONCLUSIONS
  The detectability of acute thrombus on R2* map is comparable to that on T2*WI. Regarding thrombus at distal ICA, its detectability on R2* map is superior to that on T2*WI. R2* map provide additional information to distinguish between embolic and atherothrombotic infarctions.
authors.affiliation: Division of Radiology, Department of Pathophysiological Therapeutic Science, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8503, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Shinohara
authors.affiliation: Division of Radiology, Department of Pathophysiological Therapeutic Science, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8503, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Kato
authors.affiliation: †Division of Clinical Radiology, Tottori University Hospital, Yonago 683-8504, Japan.
authors.forename: Eijiro
authors.initials: E
authors.lastname: Yamashita
authors.affiliation: Division of Radiology, Department of Pathophysiological Therapeutic Science, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8503, Japan.
authors.forename: Toshihide
authors.initials: T
authors.lastname: Ogawa
keywords: central nervous system; embolism/thrombosis; ischemia/infarction; magnetic resonance imaging