Practical signal-to-noise ratio quantification for sensitivity encoding: Application to coronary MR angiography

Jing Yu, Harsh Agarwal, Matthias Stuber, Michael Schär

Research output: Contribution to journalArticlepeer-review


Purpose: To develop and evaluate a practical method for the quantification of signal-to-noise ratio (SNR) on coronary MR angiograms (MRA) acquired with parallel imaging. Materials and Methods: To quantify the spatially varying noise due to parallel imaging reconstruction, a new method has been implemented incorporating image data acquisition followed by a fast noise scan during which radiofrequency pulses, cardiac triggering and navigator gating are disabled. The performance of this method was evaluated in a phantom study where SNR measurements were compared with those of a reference standard (multiple repetitions). Subsequently, SNR of myocardium and posterior skeletal muscle was determined on in vivo human coronary MRA. Results: In a phantom, the SNR measured using the proposed method deviated less than 10.1% from the reference method for small geometry factors (≤2). In vivo, the noise scan for a 10 min coronary MRA acquisition was acquired in 30 s. Higher signal and lower SNR, due to spatially varying noise, were found in myocardium compared with posterior skeletal muscle. Conclusion: SNR quantification based on a fast noise scan is a validated and easy-to-use method when applied to three-dimensional coronary MRA obtained with parallel imaging as long as the geometry factor remains low.

Original languageEnglish (US)
Pages (from-to)1330-1340
Number of pages11
JournalJournal of Magnetic Resonance Imaging
Issue number6
StatePublished - Jun 2011


  • SNR measurement
  • coronary MRA
  • image noise
  • parallel imaging
  • phased array coils

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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