title: Supra-aortic low-dose contrast-enhanced time-resolved magnetic resonance (MR) angiography at 3 T: comparison with time-of-flight MR angiography and high-resolution contrast-enhanced MR angiography.
abstract: BACKGROUND
  Low-dose, time-resolved, contrast-enhanced, magnetic resonance angiography (TR-CEMRA) has been described previously; however, a comparative study between low dose TR-CEMRA and time-of-flight MRA (TOF-MRA) in the diagnosis of supra-aortic arterial stenosis has not yet been published.
  
  
  OBJECTIVE
  To demonstrate the feasibility and effectiveness of low-dose TR-CEMRA compared with TOF-MRA, using high-resolution contrast-enhanced MRA (HR-CEMRA) as the reference standard.
  
  
  METHODS
  This prospective study consisted of 30 consecutive patients. All patients underwent TOF-MRA of the neck and circle of Willis and supra-aortic HR-CEMRA, followed by supra-aortic low-dose TR-CEMRA. Gadoterate meglumine (Gd-DOTA, Dotarem(®), Guerbet, Roissy CdG Cedex, France) was injected at a dose of 0.1 mmol/kg for HR-CEMRA, followed by a 0.03 mmol/kg bolus for low-dose TR-CEMRA. Three readers evaluated the assessibility and image quality, and then two readers classified each stenosis into the following categories: normal (0-30%), mild stenosis (31-50%), moderate (51-70%), severe (71-99%), and occlusion.
  
  
  RESULTS
  TR-CEMRA and HR-CEMRA showed a greater number of assessable arterial segments than TOF-MRA (P < 0.01). For TR-CEMRA, 29 cases showed within or better than the diagnostic range, whereas all 30 cases were in the diagnostic range for TOF-MRA and HR-CEMRA. For evaluation of stenosis in a total of 743 arterial segments, both TR-CEMRA and TOF-MRA results agreed with those of HR-CEMRA in 729 segments (98.1%), with excellent inter-observer agreement of TR-CEMRA; stenosis was overestimated in nine segments (1.2%) and underestimated in five segments (0.7%). For diagnosis of stenosis using 30% as the cut-off value on HR-CEMRA, the sensitivity and specificity were 88.2% and 99.3%, respectively, for the TR-CEMRA procedure, versus 94.1% and 99.6%, respectively, for TOF-MRA.
  
  
  CONCLUSIONS
  Low-dose TR-CEMRA is feasible and effective in the diagnosis of supra-aortic arterial stenosis, and could be more useful option than TOF-MRA.
authors.affiliation: Department of Radiology, The Catholic University of Korea, Seoul, Republic of Korea Department of Radiology, Eulji University, Daejeon, Republic of Korea.
authors.forename: Youn-Joo
authors.initials: YJ
authors.lastname: Lee
authors.affiliation: Department of Radiology, The Catholic University of Korea, Seoul, Republic of Korea bumrad@catholic.ac.kr.
authors.forename: Bum-soo
authors.initials: BS
authors.lastname: Kim
authors.affiliation: Department of Neurology, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Ja-Sung
authors.initials: JS
authors.lastname: Koo
authors.affiliation: Department of Radiology, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Bom-Yi
authors.initials: BY
authors.lastname: Kim
authors.affiliation: Department of Radiology, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Jinhee
authors.initials: J
authors.lastname: Jang
authors.affiliation: Department of Radiology, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Hyun Seok
authors.initials: HS
authors.lastname: Choi
authors.affiliation: Department of Radiology, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: So-Lyung
authors.initials: SL
authors.lastname: Jung
authors.affiliation: Department of Radiology, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Kook-Jin
authors.initials: KJ
authors.lastname: Ahn
mesh_terms: D000328:Adult; D000368:Aged; D001018:Aortic Diseases / Q000175:diagnosis*; D001027:Aortography / Q000379:methods*; D001158:Arteries; D003251:Constriction, Pathologic; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013997:Time Factors
chemical_list: D003287:Contrast Media
keywords: Magnetic resonance angiography; contrast media; supraaortic artery