title: ECG-gated quiescent-interval single-shot MR angiography of the lower extremities: initial experience at 3 T.
abstract: OBJECTIVE
  To evaluate the feasibility of unenhanced electrocardiography (ECG)-gated quiescent-interval single-shot magnetic resonance angiography (QISS-MRA) of the lower extremities at 3 T.
  
  
  METHODS
  Twenty-five patients with known or suspected peripheral arterial disease underwent ECG-gated QISS-MRA and contrast-enhanced MRA (CE-MRA) at 3 T. Two independent readers performed a per-segment evaluation of the MRA datasets. Image quality was rated on a four-point scale (1 = excellent to 4 = non-diagnostic; presented as medians with interquartile range). Diagnostic performance of QISS-MRA was evaluated using CE-MRA as the reference standard.
  
  
  RESULTS
  QISS-MRA and CE-MRA of all patients were considered for analysis, resulting in 807 evaluated vessel segments for each MRA technique. Readers 1 and 2 rated image quality of QISS-MRA as diagnostic in 97.3% and 97% of the vessel segments, respectively. CE-MRA was rated diagnostic in all vessel segments. Image quality of the proximal vessel segments, including the infrarenal aorta, iliac arteries, and common femoral artery, was significantly lower on QISS-MRA compared to CE-MRA [image quality score across readers: 2 (1,3) versus 1 (1,1) p < 0.001]. In the more distal vessel segments, image quality of QISS-MRA was excellent and showed no significant difference compared to CE-MRA [image quality score across readers: 1 (1,1) versus 1 (1,1) p = 0.036]. Diagnostic performance of QISS-MRA was as follows (across readers): sensitivity: 87.5% (95% CI: 80.2-92.4%); specificity: 96.1% (95% CI: 93.6-97.6%); diagnostic accuracy: 94.9% (95% CI: 92.6-96.5%).
  
  
  CONCLUSIONS
  QISS-MRA of the lower extremities is feasible at 3 T and provides high image quality, especially in the distal vessel segments.
authors.affiliation: Department of Radiology, Charité Campus Mitte, Berlin, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Knobloch
authors.affiliation: Department of Radiology, Charité Campus Mitte, Berlin, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Gielen
authors.affiliation: Department of Radiology, Charité Campus Mitte, Berlin, Germany.
authors.forename: M-T
authors.initials: MT
authors.lastname: Lauff
authors.affiliation: Department of Radiology, Franziskus-Krankenhaus, Berlin, Germany.
authors.forename: V C
authors.initials: VC
authors.lastname: Romano
authors.affiliation: Siemens Healthcare, Erlangen, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Schmitt
authors.affiliation: Siemens Healthcare, Erlangen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Rick
authors.affiliation: Department of Radiology, Charité Campus Mitte, Berlin, Germany.
authors.forename: T J
authors.initials: TJ
authors.lastname: Kröncke
authors.affiliation: Imaging Science Institute Charité - Siemens, Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Huppertz
authors.affiliation: Department of Radiology, Charité Campus Mitte, Berlin, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Hamm
authors.affiliation: Department of Radiology, Charité Campus Mitte, Berlin, Germany. Electronic address: moritz.wagner@charite.de.
authors.forename: M
authors.initials: M
authors.lastname: Wagner
mesh_terms: D000368:Aged; D003287:Contrast Media; D004562:Electrocardiography; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement; D035002:Lower Extremity / Q000098:blood supply*; D018810:Magnetic Resonance Angiography / Q000379:methods; D008297:Male; D008875:Middle Aged; D058729:Peripheral Arterial Disease / Q000175:diagnosis* / Q000503:physiopathology; D011446:Prospective Studies; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media