title: Myocardial first-pass perfusion: influence of spatial resolution and heart rate on the dark rim artifact.
abstract: Myocardial perfusion images can be affected by the dark rim artifact. This study aimed to evaluate the effects of the spatial resolution and heart rate on the transmural extent of the artifact. Six pigs under anesthesia were scanned at 1.5T using an echo-planar imaging/fast gradient echo sequence with a nonselective saturation preparation pulse. Three short-axis slices were acquired every heart beat during the first pass of a contrast agent bolus. Two different in-plane spatial resolutions (2.65 and 3.75 mm) and two different heart rates (normal and tachycardia) were used, generating a set of four perfusion scans. The percentage drop of signal in the subendocardium compared to the epicardium and the transmural extent of the artifact were extracted. Additionally, the signal-to-noise and the contrast-to-noise ratios were evaluated. The signal drop as well as the width of the dark rim artifact increased with decreased spatial resolution and with increased heart rates. No significant slice-to-slice variability was detected for signal drop and width of the rim within the four considered groups. signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) ratios decreased with increasing spatial resolution. In conclusion, low spatial and temporal resolution could be correlated with increased extent of the dark-rim artifact and with lower SNR and CNR.
authors.affiliation: Fondazione G Monasterio CNR-Regione Toscana and Institute of Clinical Physiology, Pisa, Italy. antonella.meloni@ifc.cnr.it
authors.forename: Antonella
authors.initials: A
authors.lastname: Meloni
authors.forename: Nidal
authors.initials: N
authors.lastname: Al-Saadi
authors.forename: Geir
authors.initials: G
authors.lastname: Torheim
authors.forename: Nadja
authors.initials: N
authors.lastname: Hoebel
authors.forename: H Glenn
authors.initials: HG
authors.lastname: Reynolds
authors.forename: Daniele
authors.initials: D
authors.lastname: De Marchi
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Positano
authors.forename: Silvia
authors.initials: S
authors.lastname: Burchielli
authors.forename: Massimo
authors.initials: M
authors.lastname: Lombardi
mesh_terms: D000818:Animals; D016477:Artifacts; D006321:Heart / Q000033:anatomy & histology* / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine