title: Pretreatment evaluation of peripheral vascular malformations using low-dose contrast-enhanced time-resolved 3D MR angiography: initial results in 22 patients.
abstract: OBJECTIVE
  The objective of our study was to assess the feasibility and diagnostic performance of time-resolved MR angiography (MRA) in the pretreatment evaluation of peripheral vascular malformations at 1.5 T.
  
  
  METHODS
  Twenty-two consecutive patients (15 women and seven men; mean age, 22.1 ± 12.1 years) who were known or suspected to have vascular malformations were studied using time-resolved MRA with interleaved stochastic trajectories and parallel acquisition followed by conventional MRA (n = 12). All studies were performed on a 1.5-T whole-body MR system. Image sets of time-resolved and conventional MRA were independently reviewed by two observers for image quality, level of confidence and presence, location, and classification of vascular malformations. The interobserver agreement was calculated using conventional MRA as the standard of reference.
  
  
  RESULTS
  On the basis of time-resolved MRA, nine of the lesions were categorized as high-flow arteriovenous malformations (AVMs), the remaining 13 lesions were categorized as low-flow vascular malformations or hemangiomas. There was no significant difference in the image quality grading scores between the two observers for time-resolved MRA (p = 0.61) and conventional MRA (p = 0.54). The kappa coefficient revealed good agreement (κ = 0.76) between time-resolved MRA and conventional MRA. Both observers visualized fine vascular details with higher confidence in two patients on conventional MRA. The additional functional information regarding feeding artery and flow patterns provided by time-resolved MRA was confirmed by digital subtraction in all nine cases.
  
  
  CONCLUSIONS
  Time-resolved MRA provided the temporal information needed for the appropriate classification of vascular malformations, enabling visualization of both the arterial feeders and draining veins. Furthermore, time-resolved MRA has the potential to be used as an initial and screening diagnostic tool obviating conventional MRA to categorize these lesions and determine their extent to correctly guide treatment.
authors.affiliation: Department Diagnostic and Interventional Radiology, University of Tuebingen, Germany. ulrich.kramer@med.uni-tuebingen.de
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kramer
authors.forename: Ulrike
authors.initials: U
authors.lastname: Ernemann
authors.forename: Michael
authors.initials: M
authors.lastname: Fenchel
authors.forename: Achim
authors.initials: A
authors.lastname: Seeger
authors.forename: Gerhard
authors.initials: G
authors.lastname: Laub
authors.forename: Claus D
authors.initials: CD
authors.lastname: Claussen
authors.forename: Stephan
authors.initials: S
authors.lastname: Miller
mesh_terms: D001165:Arteriovenous Malformations / Q000175:diagnosis*; D003287:Contrast Media / Q000008:administration & dosage; D005240:Feasibility Studies; D005260:Female; D006391:Hemangioma / Q000175:diagnosis*; D006801:Humans; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D016491:Peripheral Vascular Diseases / Q000175:diagnosis*; D018709:Statistics, Nonparametric; D019043:Vascular Neoplasms / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D003287:Contrast Media