title: Time-resolved MR angiography with generalized autocalibrating partially parallel acquisition and time-resolved echo-sharing angiographic technique for hemodialysis arteriovenous fistulas and grafts.
abstract: OBJECTIVE
  To evaluate the imaging of hemodialysis arteriovenous (AV) fistulas and grafts with use of magnetic resonance (MR) angiography with generalized autocalibrating partially parallel acquisition (GRAPPA) and time-resolved echo-sharing angiographic technique (TREAT) and compare the findings with those of digital subtraction angiography (DSA).
  
  
  METHODS
  The vascular tree directly related to AV fistulas and grafts was divided into nine segments. Images of each segment obtained on GRAPPA MR angiography were evaluated for the presence of stenosis, occlusion, and any other disease (eg, pseudoaneurysm) by two independent observers and compared with a consensus reading of the same segments on DSA imaging. Sensitivity and specificity were calculated with use of DSA as the gold standard modality, and each image on MR angiography and DSA was rated for quality. Linear-weighted kappa scores were calculated as a measure of interobserver variability in the detection of pathologic processes.
  
  
  RESULTS
  A total of 80 segments were evaluated by each observer. For both observers, sensitivity rates for the detection of stenosis, occlusion, and any disease were 100% (95% CI, 52%-100%), 100% (95% CI, 20%-100%), and 100% (95% CI, 60%-100%), respectively. For observer 1, specificity rates for the detection of stenosis, occlusion, and any disease were 96% (95% CI, 88%-99%), 100% (95% CI, 94%-100%), and 96% (95% CI, 88%-99%), respectively. For observer 2, the specificity rates for the detection of stenosis, occlusion, and any disease were 93% (95% CI, 84%-98%), 100% (95% CI, 94%-100%), and 93% (95% CI, 84%-97%), respectively. Linear-weighted kappa values for MR angiography and DSA were 0.78+/-0.084 and 0.62+/-0.152, respectively.
  
  
  CONCLUSIONS
  Time-resolved MR angiography with GRAPPA and TREAT offers excellent image quality and provides an accurate and reliable modality for the detection of pathologic processes in hemodialysis AV fistulas and grafts.
authors.affiliation: Department of Radiology and Feinberg School of Medicine, Northwestern University, and Siemens Medical Solutions, Chicago, Illinois 60611, USA.
authors.forename: Christina
authors.initials: C
authors.lastname: Pinto
authors.forename: Ryan
authors.initials: R
authors.lastname: Hickey
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Carroll
authors.forename: Kent
authors.initials: K
authors.lastname: Sato
authors.forename: Karin
authors.initials: K
authors.lastname: Dill
authors.forename: Reed A
authors.initials: RA
authors.lastname: Omary
authors.forename: Randall
authors.initials: R
authors.lastname: Kroeker
authors.forename: Orlando
authors.initials: O
authors.lastname: Simonetti
authors.forename: James C
authors.initials: JC
authors.lastname: Carr
mesh_terms: D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D001166:Arteriovenous Shunt, Surgical; D002138:Calibration; D003287:Contrast Media; D005260:Female; D006083:Graft Occlusion, Vascular / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D006435:Renal Dialysis; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media