title: Time-resolved contrast-enhanced magnetic resonance angiography (CEMRA) of the left atrium-pulmonary veins complex with half dose of intravenous gadolinium-based contrast agent. Technical feasibility and comparison with a conventional CEMRA, full contrast dose protocol.
abstract: OBJECTIVE
  To evaluate feasibility and image quality of time-resolved contrast-enhanced magnetic resonance angiography (CEMRA) of the left atrium-pulmonary veins (LA-PV) complex with half dose of intravenous gadolinium-based contrast agent (GBCA) in patients candidate to percutaneous radiofrequency ablation of atrial fibrillation.
  
  
  METHODS
  Fifty-seven patients underwent CEMRA of the LA-PV complex on a 1.5T MRI scanner. On 24/57 patients, a conventional fast-spoiled gradient-echo (FSPGR) CEMRA acquisition was run using 0.2 mL/kg of 0.5M GBCA at 2 mL/s flow rate (protocol A), while in 33/57 patients a time-resolved multiphase CEMRA sequence (Time-Resolved Imaging of Contrast KineticS, TRICKS) was performed after intravenous injection of 0.1 mL/kg of the same GBCA at 3 mL/s flow rate (protocol B). Contrast enhancement was measured in the LA (LAe) and in the PA (PAe), and the LAe/PAe ratio was calculated. Diagnostic quality of Maximum Intensity Projection (MIP), Volume Rendering (VR), and Virtual Endoscopy (VE) reconstructions was also assessed visually using a semiquantitative score.
  
  
  RESULTS
  LAe was comparable with both protocols, while PAe was lower with protocol B than with protocol A (p = 0.0217). Moreover, the LAe/PAe ratio was significantly higher with protocol B than with protocol A (p = 0.0044). Finally, image quality of MIP, VR, and VE reconstructions was significantly better with protocol B than with protocol A (p = 0.0005, p = 0.0001, and p = 0.005, respectively).
  
  
  CONCLUSIONS
  CEMRA of the LA-PV complex is feasible with TRICKS and half-dose GBCA and yields better separation between the LA-PV complex and the PA, as well as better image quality of MIP, VR, and VE reconstructions than a conventional FSPGR sequence performed with full GBCA dose.
authors.affiliation: Diagnostic and Interventional Radiology, Via Paradisa 2, 56100 Pisa, PI, Italy. lfaggioni@sirm.org
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Faggioni
authors.forename: Virna
authors.initials: V
authors.lastname: Zampa
authors.forename: Simona
authors.initials: S
authors.lastname: Ortori
authors.forename: Eugenia
authors.initials: E
authors.lastname: Picano
authors.forename: Raffaele
authors.initials: R
authors.lastname: De Lucia
authors.forename: Ezio
authors.initials: E
authors.lastname: Soldati
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Bongiorni
authors.forename: Emanuele
authors.initials: E
authors.lastname: Neri
authors.forename: Carlo
authors.initials: C
authors.lastname: Bartolozzi
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media / Q000008:administration & dosage; D005240:Feasibility Studies; D006325:Heart Atria / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007275:Injections, Intravenous; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008536:Meglumine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D008875:Middle Aged; D009942:Organometallic Compounds / Q000008:administration & dosage; D011667:Pulmonary Veins / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine