title: Value of subtraction in fat-saturated three-dimensional contrast-enhanced magnetic resonance angiography of the hemodialysis fistula.
abstract: OBJECTIVE
  To evaluate image subtraction in a three-dimensional contrast-enhanced magnetic resonance angiography (3D CE-MRA) using fat suppression for the hemodialysis fistula.
  
  
  METHODS
  Fifteen patients suffering from hemodialysis fistula dysfunction were imaged with 3D CE-MRA using fat suppression and digital subtraction angiography (DSA). Non-subtracted and subtracted MRA images using maximum intensity projection (MIP) were constructed and the validity of the MRA interpretations of the degree of vascular stenoses was evaluated using DSA as the standard of reference. Image quality was assessed using qualitative analysis (vessel contrast) and quantitative analysis (contrast-to-noise ratio (CNR) of the vessel versus the background).
  
  
  RESULTS
  In the vessels with stenosis of 50% or greater, the sensitivity and specificity of the non-subtracted MRA were 89.5% and 81.8%, respectively, and of the subtracted MRA 89.5% and 86.4%, respectively. There was no significant difference in the detectability of stenoses between either MRA. The vessel contrast of the anterior interosseous artery and the CNR of the anterior interosseous artery versus the background on the subtracted MRA were significantly superior to those on the non-subtracted MRA. With regard to the radial artery and cephalic vein, there was no significant difference in the vessel contrast and CNR between either MRA.
  
  
  CONCLUSIONS
  Both subtracted and non-subtracted MRA techniques are useful in detecting hemodialysis fistula dysfunction.
authors.affiliation: Department of Radiology, University of Tsukuba Hospital, Ibaraki, Japan. nbyktakahashi@yahoo.co.jp
authors.forename: N
authors.initials: N
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Sato
authors.forename: M
authors.initials: M
authors.lastname: Niitsu
authors.forename: Y
authors.initials: Y
authors.lastname: Saida
mesh_terms: D015901:Angiography, Digital Subtraction; D001166:Arteriovenous Shunt, Surgical; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D021621:Imaging, Three-Dimensional; D007275:Injections, Intravenous; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis; D012680:Sensitivity and Specificity; D013382:Subtraction Technique
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA