title: Time-resolved and bolus-chase MR angiography of the leg: branching pattern analysis and identification of septocutaneous perforators.
abstract: OBJECTIVE
  The goal of this study was to compare time-resolved MR angiography (MRA) and bolus-chase MRA in the identification of peroneal artery septocutaneous perforators and for classification of the branching pattern of the arterial tree in the leg in a cohort of candidates for fibular free flap transfer operations.
  
  
  METHODS
  Retrospective analysis was performed on imaging data from 53 legs of 27 patients (age range, 27-88 years) who underwent time-resolved MRA (FLASH; TR/TE, 2.5/1.0; flip angle, 22°; voxel dimensions, 1.54 × 1.25 × 1.5 mm; acquisition time, 2.27 s/frame) and bolus-chase MRA (FLASH; 3.2/1.2; flip angle, 25°; voxel dimensions, 0.94 × 0.89 × 1 mm) at 3 T with gadobenate dimeglumine administered at 0.05 and 0.10 mmol/kg, respectively. The branching pattern was analyzed; the total number of septocutaneous perforators for each leg was calculated from the time-resolved and bolus-chase MRA data; and the results were combined. The total and average number of septocutaneous perforators per leg and the frequency of various branching patterns were calculated. The techniques were compared in terms of branching pattern and number of visible septocutaneous perforators.
  
  
  RESULTS
  A total of 84 septocutaneous perforators (1.58 ± 1.05 [SD] per leg) were identified. Pattern 1A was found in 42 legs; 1B, two legs; 2A, one leg; 2B, one; 3A, four; 3B, one; and 3D, two legs. Classification with time-resolved MRA was successful for 53 legs and with boluschase MRA for 51 legs (Z = 0.713, p = 0.24, one-tailed, not significant). Twenty-two septocutaneous perforators were identified with time-resolved MRA and 82 with bolus-chase MRA.
  
  
  CONCLUSIONS
  MRA of the leg can be used to investigate the branching pattern and identify septocutaneous perforators in a single step. With the imaging parameters and contrast dose used in this study, septocutaneous perforators can be better identified with boluschase MRA, although this result may be partially related to the higher gadolinium dose used in this technique.
authors.affiliation: Department of Radiology, University Hospitals of Cleveland, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: Gurpreet S
authors.initials: GS
authors.lastname: Sandhu
authors.forename: Rod P
authors.initials: RP
authors.lastname: Rezaee
authors.forename: Katherine
authors.initials: K
authors.lastname: Wright
authors.forename: John A
authors.initials: JA
authors.lastname: Jesberger
authors.forename: Mark A
authors.initials: MA
authors.lastname: Griswold
authors.forename: Vikas
authors.initials: V
authors.lastname: Gulani
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001158:Arteries; D005260:Female; D006801:Humans; D007866:Leg / Q000098:blood supply*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013997:Time Factors