title: Evaluation of blood volume by use of blood oxygen level-dependent magnetic resonance imaging in a cuff-compression model: usefulness of calculated echo time image.
abstract: OBJECTIVE
  Separate assessment of changes in blood oxygenation and blood volume is required in blood oxygen level-dependent (BOLD) imaging. We developed a calculated echo time (TE) imaging technique designed to minimize effects of blood oxygenation and to evaluate blood volume specifically.
  
  
  METHODS
  Dynamic 3T multi-echo BOLD images of calf muscle were acquired from six healthy volunteers by use of a cuff-compression model. Calculated TE images at TE = 0 ms (cTE0) and T2* map (T2*) were calculated from acquired multi-echo images. The time courses of the mean value for the entire calf muscles in cTE0, in acquired BOLD images at TE = 45.2 ms (aTE45), and in T2* were obtained. The Euclidean distances between the two pairs of time courses were calculated: distance between aTE45 and T2* (D at), and that between cTE0 and T2* (D ct). The difference between D at and D ct was tested by use of the Wilcoxon signed rank test.
  
  
  RESULTS
  D at was significantly different from D ct (P = 0.031), indicating that the time course of cTE0 was significantly different from that of blood oxygenation-weighted images (T2* and aTE45).
  
  
  CONCLUSIONS
  The effect of blood oxygenation could be minimized using cTE0. Thus, signal intensity changes of cTE0 reflected changes in blood volume more specifically.
authors.affiliation: Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Nishii
authors.forename: Atsushi K
authors.initials: AK
authors.lastname: Kono
authors.forename: Mizuho
authors.initials: M
authors.lastname: Nishio
authors.forename: Katsusuke
authors.initials: K
authors.lastname: Kyotani
authors.forename: Kouya
authors.initials: K
authors.lastname: Nishiyama
authors.forename: Kazuro
authors.initials: K
authors.lastname: Sugimura
mesh_terms: D000328:Adult; D001811:Blood Volume Determination / Q000379:methods*; D006801:Humans; D007866:Leg / Q000098:blood supply; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010100:Oxygen / Q000097:blood*; D055815:Young Adult
chemical_list: D010100:Oxygen