title: Practical approaches to the evaluation of signal-to-noise ratio performance with parallel imaging: application with cardiac imaging and a 32-channel cardiac coil.
abstract: In this work, two practical methods for the measurement of signal-to-noise-ratio (SNR) performance in parallel imaging are described. Phantoms and human studies were performed with a 32-channel cardiac coil in the context of ultrafast cardiac CINE imaging at 1.5 T using steady-state free precession (SSFP) and TSENSE. SNR and g-factor phantom measurements using a "multiple acquisition" method were compared to measurements from a "difference method". Excellent agreement was seen between the two methods, and the g-factor shows qualitative agreement with theoretical predictions from the literature. Examples of high temporal (42.6 ms) and spatial (2.1x2.1x8 mm3) resolution cardiac CINE SSFP images acquired from human volunteers using TSENSE are shown for acceleration factors up to 7. Image quality agrees qualitatively with phantom SNR measurements, suggesting an optimum acceleration of 4. With this acceleration, a cardiac function study consisting of 6 image planes (3 short-axis views, 3 long-axis views) was obtained in an 18-heartbeat breath-hold.
authors.affiliation: Department of Clinical Radiology, University Hospitals-Grosshadern, Ludwig-Maximilians-University, Munich, Germany. sreeder@wisc.edu
authors.forename: Scott B
authors.initials: SB
authors.lastname: Reeder
authors.forename: Bernd J
authors.initials: BJ
authors.lastname: Wintersperger
authors.forename: Olaf
authors.initials: O
authors.lastname: Dietrich
authors.forename: Titus
authors.initials: T
authors.lastname: Lanz
authors.forename: Andreas
authors.initials: A
authors.lastname: Greiser
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.forename: Gary M
authors.initials: GM
authors.lastname: Glazer
authors.forename: Stefan O
authors.initials: SO
authors.lastname: Schoenberg
mesh_terms: D005260:Female; D006321:Heart / Q000033:anatomy & histology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D019028:Magnetic Resonance Imaging, Cine / Q000295:instrumentation*; D008297:Male; D019047:Phantoms, Imaging