title: Quality assessment of cardiovascular magnetic resonance in the setting of the European CMR registry: description and validation of standardized criteria.
abstract: BACKGROUND
  Cardiovascular magnetic resonance (CMR) has become an important diagnostic imaging modality in cardiovascular medicine. However, insufficient image quality may compromise its diagnostic accuracy. We aimed to describe and validate standardized criteria to evaluate a) cine steady-state free precession (SSFP), b) late gadolinium enhancement (LGE), and c) stress first-pass perfusion images. These criteria will serve for quality assessment in the setting of the Euro-CMR registry.
  
  
  METHODS
  Thirty-five qualitative criteria were defined (scores 0-3) with lower scores indicating better image quality. In addition, quantitative parameters were measured yielding 2 additional quality criteria, i.e. signal-to-noise ratio (SNR) of non-infarcted myocardium (as a measure of correct signal nulling of healthy myocardium) for LGE and % signal increase during contrast medium first-pass for perfusion images. These qualitative and quantitative criteria were assessed in a total of 90 patients (60 patients scanned at our own institution at 1.5T (n=30) and 3T (n=30) and in 30 patients randomly chosen from the Euro-CMR registry examined at 1.5T). Analyses were performed by 2 SCMR level-3 experts, 1 trained study nurse, and 1 trained medical student.
  
  
  RESULTS
  The global quality score was 6.7±4.6 (n=90, mean of 4 observers, maximum possible score 64), range 6.4-6.9 (p=0.76 between observers). It ranged from 4.0-4.3 for 1.5T (p=0.96 between observers), from 5.9-6.9 for 3T (p=0.33 between observers), and from 8.6-10.3 for the Euro-CMR cases (p=0.40 between observers). The inter- (n=4) and intra-observer (n=2) agreement for the global quality score, i.e. the percentage of assignments to the same quality tertile ranged from 80% to 88% and from 90% to 98%, respectively. The agreement for the quantitative assessment for LGE images (scores 0-2 for SNR <2, 2-5, >5, respectively) ranged from 78-84% for the entire population, and 70-93% at 1.5T, 64-88% at 3T, and 72-90% for the Euro-CMR cases. The agreement for perfusion images (scores 0-2 for %SI increase >200%, 100%-200%,<100%, respectively) ranged from 81-91% for the entire population, and 76-100% at 1.5T, 67-96% at 3T, and 62-90% for the Euro-CMR registry cases. The intra-class correlation coefficient for the global quality score was 0.83.
  
  
  CONCLUSIONS
  The described criteria for the assessment of CMR image quality are robust with a good inter- and intra-observer agreement. Further research is needed to define the impact of image quality on the diagnostic and prognostic yield of CMR studies.
authors.affiliation: Department of Cardiology, Center of Cardiac Magnetic Resonance (CRMC), University Hospital Lausanne, Lausanne, Switzerland.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Klinke
authors.forename: Stefano
authors.initials: S
authors.lastname: Muzzarelli
authors.forename: Nathalie
authors.initials: N
authors.lastname: Lauriers
authors.forename: Didier
authors.initials: D
authors.lastname: Locca
authors.forename: Gabriella
authors.initials: G
authors.lastname: Vincenti
authors.forename: Pierre
authors.initials: P
authors.lastname: Monney
authors.forename: Christian
authors.initials: C
authors.lastname: Lu
authors.forename: Detlev
authors.initials: D
authors.lastname: Nothnagel
authors.forename: Guenter
authors.initials: G
authors.lastname: Pilz
authors.forename: Massimo
authors.initials: M
authors.lastname: Lombardi
authors.forename: Albert C
authors.initials: AC
authors.lastname: van Rossum
authors.forename: Anja
authors.initials: A
authors.lastname: Wagner
authors.forename: Oliver
authors.initials: O
authors.lastname: Bruder
authors.forename: Heiko
authors.initials: H
authors.lastname: Mahrholdt
authors.forename: Juerg
authors.initials: J
authors.lastname: Schwitter
mesh_terms: D000328:Adult; D016477:Artifacts; D055424:Cardiac-Gated Imaging Techniques; D002318:Cardiovascular Diseases / Q000175:diagnosis*; D003287:Contrast Media; D005060:Europe; D005260:Female; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000592:standards*; D008297:Male; D011785:Quality Assurance, Health Care; D012042:Registries; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio
chemical_list: D003287:Contrast Media